annual report 2004 · 2007. 1. 12. · 2 cerc – annual report 2004 cerc combustion engine...

CERC – Annual Report 20041

CERCChalmers University of Technology

Combustion Engine Research Center

AnnualReport2004


CERCCombustion Engine Research Center

Table of Contents

The coverCut-plane through the center of the spray,

colored and elevated by temperature seen frombelow.

General Background

The Centre of Excellence in Internal Combustion Engines at Chalmers, theCombustion Engines Research Centre (CERC), was formally established onNovember 1, 1995, and inaugurated on March 26, 1996.

The decision to establish the Centre was made by the Board of ChalmersUniversity of Technology and was based on a three-party agreement betweenthe Swedish Board for Technical and Industrial Development (NUTEK), ChalmersUniversity of Technology and a group of five Swedish industrial companies:Husqvarna AB, SAAB Automobile AB, Scania CV AB, Volvo Car Corporation andVolvo Truck Corporation. The agreement defines each party’s responsibilitieswith respect to financial commitment, scientific goals and the use of researchresults.

In 1997 responsibility for co-ordinating the Centre was transferred to the SwedishNational Energy Administration (STEM), later re-named the Swedish EnergyAgency.

The following seven industrial companies are full members of the Centrein Stage 4.

ABB Automation Products ABAB Volvo Penta

Statoil ASVolvo Power Train ABVolvo Car CorporationScania CV ABSaab Automobile Powertrain AB

Stage 4 will span two years, starting from 2004. When it ends, ten years from itsinception, the centre is expected to be less dependent on financial supportfrom STEM and to have greatly strengthened the relationship between theUniversity and industry.

The Centre is defined as one of twenty-eight Competence Centres in Sweden oflong term importance for Swedish industry. It is a forum where joint industrialand academic research is performed. The purpose is to provide and build up aconcentrated inter-disciplinary research group in which the participatingcompanies can actively participate, and gain the benefit of long-term perspectives.

The development of future environmentally friendly vehicles will requireincreased research and the development of new generations of high efficiency,low CO

2, near-zero emission engine combustion processes that can utilize

renewable energy sources.

The Centre’s long-term objectives are to carry out fundamental research ofsignificant industrial interest focused on the Otto and Diesel combustionprocesses, including alternative fuels and control systems with the main targetsto reduce specific fuel consumption and exhaust gas emission. Transfer ofknowledge between the academic community and the industrial members in aninter-disciplinary manner is considered an essential benefit to all partners.Strategically important research areas are decided by the scientists at Chalmersin co-operation with representatives from industry and advice from the ScientificAdvisory Board. The research projects cover areas of both fundamental andapplied interest.

The governing board consists of three members from the academic community,five members from the participating companies and one member from theSwedish Energy Agency (STEM). The chairman is one of the industrialrepresentatives.

2 General background

3 Preface

4 Summary

5 Scientific results and future outlook

6 Modeling of Spray Formation, Ignition andCombustion in Internal Combustion Engines

9 Spray-Guided Gasoline Direct Injection

15 Optical TWO-PHASE diagnostics

21 Theoret ical and Exper imentalInvestigations of Combustion of Shor tDuration Small Diameter Sprays in DilutedAir

24 Torque sensors for engine applications

26 Nanoparticles

28 Injection Strategies

29 Fischer-Tropsch Fuels for Low Emissions inDiesel Engines

31 Human resources

32 Finances during theperiod 2004-2005

34 References


Preface

Fossil fuels for transportation systems are predicted to be available for at leastfor another 50 years before being substituted by hydrogen. In the short tomedium term powertrain optimisation, development of efficient combustionengines and alternative fuels will be required to meet customer demands, andto meet emission legislation and global environmental requirements such asreducing carbon dioxide emissions.The changes that are required to reach these targets are major challenges to theautomotive and energy industry and should have significant influence on theresearch program at CERC. There is also a trend towards closer collaborationbetween industry and universities, giving the universities opportunities to beimportant partners in the required research programs.Within CERC research is focussing on sprays and spray combustion in dieseland gasoline engines with the goals to reduce both fuel consumption andemissions. Internal combustion engine research is extremely multidisciplinary,involving advanced experimental techniques such as laser spectroscopy, numericalmodelling of both mechanical and thermodynamic systems and closed-loopengine control.

Research is currently being carried out in several projects on different types ofspray formation, spray diagnostics and flame propagation, most of which areso-called “horizontal projects” of common interest to many or most of the Centre’smembers.

The CERC competence centre should be a neutral platform in which industrialand academic experts can meet and perform research of common interest. Anexpected outcome is enhanced industrial orientation at the University, whileindustrial concerns should take the opportunity to reduce their basic and appliedresearch costs and to increase their knowledge by participating even moreactively in research programs.

The increased performance demands and complexity of future engines will leadto intensified international collaboration between engine manufacturers. This isa real challenge for CERC. In order to remain a regional and national universitypartner supplying Swedish industry with highly competent engineers we mustalso, at the same time, be part of the elite international research community.

The future research strategy should, if possible, address the whole energy chainof conversion i.e. fuel-combustion-control-catalysis. Several renowned researchgroups, working in close collaboration at Chalmers, would offer a strong nationaland international research partnership for the development of more efficient,environmentally friendly combustion engines for the future.

In addition to the research results and the successful collaboration between theUniversity and industry the education of engineers and scientists for theautomotive industry in Sweden might provide strong enough justification in itsown right to support a high level of combustion research at Chalmers.

CERC has successfully completed nine years of engine combustion researchand its collaboration and partnership with the Swedish motor industry is wellestablished. Discussion concerning future (post-2005) plans has started and allinvolved parties are determined to build on the success to date and to developeven closer integration of the research activities of Swedish industry and theUniversity.

Sivert HiljemarkDirectorCombustion Engine Research Centre


Summary

Long-term objectives of CERC are to perform high quality fundamental and appliedresearch to reduce harmful exhaust gas emissions and fuel consumption based on abetter understanding of the underlying physical combustion processes. The researchshould be relevant to the industry contributing to its development of sustainable energyand transportation systems in the medium term perspective of 10 – 15 years. CERCprojects are interdisciplinary and generally problem-focused, requiring ‘horizontal’networking across traditional university structures.

Since its start nine years ago CERC has generated substantial intellectual knowledge, astate-of-the-art computational and experimental infrastructure, and results that are usedby industry for decision-making and product development. The close involvement of theindustry brings industrial experience and practice to the centre, which is not only extremelybeneficial for the projects, but also for the graduate students, who can easily develop anetwork and benefit from wider interdisciplinary supervision.

In Stage 4 seven companies are supporting and partnering CERC, including all of themajor Swedish engine manufacturers. The scientific output has been significant, withmore than 200 national and international publications, 10 doctoral theses, 13 licentiatetheses and 61 MSc diploma projects since its inception in 1995

The main objectives of the competence centre are to:

provide a forum where industry and academia perform research ofmutual interest.gain fundamental knowledge of the physical processes involved inhigh-pressure spray combustion via experiments and modelling.study new combustion concepts leading to cleaner and moreefficient engines.transfer knowledge to industryeducate engineers and scientists for the engine industry.

In the year 2004 three new PhD research projects were started.Optimisation of the injector strategy to reduce soot and fuel consumption followed byreducing NO

X by large amounts of EGR will be researched by an industrial PhD student

and The influence of Fischer-Tropsch fuels on advanced diesel combustion system withrespect to emission and fuel consumption will be investigated in the other two projects.Statoil will support and participate in the development of suitable FT fuels and the fourpartners from the engine-industries are actively involved in the applied research studiesof the diesel engine. These two Fischer-Tropsch projects are being financially supportedby Emissionsforsknings-programmet (EMFO).

The annual seminar and International Advisory Board meeting in March was attendedby forty engineers and researchers from the university and industrial companies, andProfessor Chris Atkinson from West Virginia University,USA summarised CERC’sachievements and his views on the future as follows.

“In summary, I believe that CERC is fulfilling its mission very well. I see that CERC’scloser alignment with its industrial partners is essential for its ongoing survival as astand-alone organization. CERC continues to conduct a very healthy internal debate onwhat its role as an academic unit should be, and the results of this debate need to betranslated into actions with regard to generating direct financial support from CERC’sindustrial partners and other relevant funding bodies.”

Continued funding from STEM or other national authorities together with ongoingindustrial interest and commitment will be prerequisites for a successful CERC researchprogramme after the year 2005. Combined with further strengthening of the networkbetween the universities, and greater inclusion of the industrial companies will allowsignificant advances in Swedish combustion research to be made.


Worldwide awareness of environmentalissues is increasing and fulfilling theKyoto Protocol agreements from 1997will be very important in order to reduceCO

2 levels and their effect on global

warming.

Legislation on hazardous exhaustemissions is being tightened year by year.Zero emission vehicles are required inCalifornia, and the European carindustries have committed themselves toreducing emissions from the average carto less than 140 g/km CO

2 by 2008.

Fossil fuels are predicted to be availablefor at least another 50 years and theassociated infrastructure and distributionnetworks are reliable and wellestablished. Hydrogen-fuelled vehiclesare considered to be the most viablesolution for producing ‘zero-emission’vehicles and already hydrogen is beingproduced, stored and transported, forinstance to the chemical industry. Inother words, the technology required toproduce and run hydrogen-fuelledvehicles is known, in principal, but itwill take many years to agree, create andestablish a credible supply anddistribution system satisfying therequirements and expectations of theautomotive industry and its customers.

In the meantime, the conventionalcombustion engine will be furtherresearched and developed. New enginetechnologies and combustion processeswill unite the benefits of diesel andgasoline engines, and in combinationwith sophisticated exhaust emissionsystems and alternative fuels it will bepossible to achieve very low emissionlevels (figure 1).The acceptance of and confidence inhybrid vehicles have increased, andhybrid vehicle systems are compatiblewith both improved fuel economy andreduced exhaust emissions.

Scientific resultsand future outlook

However, their cost and weight are stillconcerns. Alternative fuels will increasein importance and most likely besupported by tax incentives.

Cleaner and environmentally friendlyfuels from gas (GTL-fuels such asmethanol, DME and diesel fuel producedby the Fischer-Tropsch process) are ofinterest for the near foreseeable future.Expected future developments willinclude a gradual merger of diesel andgasoline combustion principles.Regardless of its type, the fuel will besupplied directly into the cylinder andthe charge will be partly homogeneous,without rich zones, but stratified.Controlling spraying and mixingparameters will be important under allengine conditions.

Ignition may occur by compression orbe spark-assisted. In the near to mid-term (by ~2015) thermal mechanismswill be used for ignition control, whilein the long-term (beyond 2015) tailor-made fuels may offer interesting

opportunities. Since “HCCI” engines havelow specific power and downsizing is apreferred future trend, efficient high-pressure ratio-charging systems will needto be developed. Control systems willincrease in importance and must bedeveloped to be capable of handling ahuge amount of operational parameterswith feedback control allowing large,rapid jumps in operational conditions(mode changes).

CERC’s research is to a large extentfocussed on the modelling, combustionand control of the fuel spray, which isof great importance to the motorindustry’s need to reduce CO

2 and other

emissions. The future research strategyat CERC after 2005 should, however,address the whole energy chain ofconversion i.e. fuel-combustion-control-catalysis, if possible. Closer collaborationbetween research groups at Chalmers,industrial concerns and other universitieswould strengthen engine combustionresearch both in Sweden andinternationally.

Figure 1

Possible Strategies for future emissions standards


Modeling of Spray Formation, Ignition and Combustionin Internal Combustion Engines

Niklas Nordin, Project leader,

Assist. Professor

Valeri Golovitchev, AssociateProfessor

Jerzy Chomiak, Professor

Emeritus

Fabian Kärrholm, PhD student

Niklas Nordin, Researcher, Ph.D.,Thermo and Fluid Dynamics

I want to create a research-tool for makingreliable spray combustion simulations,where the models behave in a good andexpected manner, so that, someday, realpredictive spray simulations will be possible.As the computational power is increasing,so is the possibility to make more realisticcomputations. This requires, however, thatthe computational tool can take advantageof this ‘power’ and is reliable enough, sothat it can be used to reduce both the timeand cost when developing a new andcleaner engine.

It has already been established by the CERCboard that the main foci of the work shouldbe:

Development of a new atomizationmodelTesting of turbulence models using anLES approachDevelopment of a multi-componentfuel evaporation modelDevelopment of a new CFD platformwith multi-processor capabilities

In the year 2004 the spray/turbulence/meshinteraction problem has been studied ingreat detail. Since modeling Lagrangiansprays is a difficult topic for a new studentit was decided to change the order in whichthe work should be performed, and toswitch the chronological order of the firstand second topics in the above list. It wasmore appropriate for the new Ph.D. student,Fabian Peng Kärrholm, to start byinvestigating how sprays behave at differentmesh-resolutions and in different RANSturbulence models. This is essential formodeling sprays and for understandinghow turbulence affects the spray, and it willalso provide a good foundation for futurework in which LES models will be used.This work has resulted in the paperNumerical Investigation of Mesh/Turbulence/Spray Interaction for DieselApplications, which has been accepted forthe May 2005 SAE Fuels and LubricantsMeeting in Rio de Janeiro, so only the mainconclusions will be summarized here.

The Computational Fluid Dynamics (CFD) codeused is based on the FOAM package. A gooddescription of the FOAM package can be foundin a recent publication by Jasak et al. [189], wherethe advantages of using object-orientation isgiven.

It was suggested in the book Modeling EngineSpray and Combustion Processes, by Stiesch,that the turbulent length scale should belimited in the jet core region. This turbulentlength-scale limiter was implemented in FOAMand tested using different meshes andturbulence models. It was found to have apositive effect, especially on the vaporpenetration and it also reduced the sensitivityto the mesh resolution, integration step andthe initial turbulence parameters. In Figures1 and 2 we can see the difference in resultsobtained with and without a length-scalelimiter. Clearly, in the studied case the mesh-dependency is reduced when a length-scalelimiter is used, since the difference betweenthe vapor penetration for the different meshesis reduced.

This is a significant improvement as it allowsdirect comparison of breakup models, interalia, where the effects of the mesh havebeen reduced to a minimum. Otherwise,model constants in any spray simulationare not really constants, but functions ofthe mesh resolution. This makes modelingin engine processes especially difficult asthe mesh resolution can vary in time.

Simulations with multicomponent treatmentshave been compared with experimental dataacquired by A. Magnusson in the high-pressure/high temperature constant volume vessel usingthe IDEA fuel at Chalmers. The main purposeof the modeling was to verify that the full rangeof pressures representative of early injection fromHCCI to high-pressure, diesel-relevantconditions, could be handled and goodagreement was found between the simulationsand experimental data. Vapor penetrationagreement was reasonable for the lower pressures(4 bar) and very good in the high pressure range(10-61 bar). Future research will focus oninvestigating the effects of cavitation on dropletformation/ spray angles. A cavitation code willbe used to reproduce the experiments made byL. Ganippa in a scaled-up plexi-glass nozzle, andwhen the model/code has been validatedsimulations will be performed on a realistic dieselinjector with the aim to develop a newatomization model that can give betterpredictions of spray angles, velocity and dropletsize distribution, given relevant physicalparameters such as fuel specifications, injectionpressure and fuel injector characteristics.

Fig. 1 Spray simulation results without a length-scale limiter for a coarse, mediumand fine mesh.


To analyze certain new trends in advanced dieselengine development (e.g. DI Diesel HCCI engines,MK combustion, etc.) and evaluate different fuelinjection strategies, the KIVA-3V, rel.2 version ofthe KIVA code was still used, with modificationsof sub-models of diesel combustion including sprayatomization, droplet collisions, evaporationaccounting for multicomponent fuels, coupled withnew versions of chemistry/turbulence interactionmodels, improved formulae and combustionkinetics for diesel oil surrogates. Modifications ofspray atomization and droplet collision models arerequired to simulate the retarded fuel injectionprofiles applied in DI Diesel engines to realize theMK (Modulated Kinetics) combustion regime,which substantially reduces the emissions formedat moderate loads. Improved models were used topredict the combustion development of fuel spraysinjected into the EGR atmosphere, controlled bythe mixture composition obtained with differentinjection rate profiles, including split and multipleinjections.

A more accurate model based on data from theinteractive NIST database (SuperTrapp) wasused to predict thermodynamic and transportproperties of fluid blends representing thecomponents of a real diesel fuel. The modelperforms phase equilibria calculations andreturns key thermo physical (density, enthalpy,etc.) properties of all phases and transport(viscosity, conductivity, etc.) properties of thegaseous components of the “constructed” modelfuel. The model has been described by A.Häggström in her licentiate thesis Modelling andSimulation of Diesel Sprays: LagrangianMulticomponent Fuel Treatment. The results

Fig. 2 Spray simulation results with a length-scale limiter for a coarse, mediumand fine mesh.

substantiate the two-component diesel oilsurrogate model developed for CERC.

As shown in Fig. 3 (a-b), combinations ofdifferent spray (secondary atomization +collision) models can lead to different patternsof combustion development. In particular, acombination of KHRT (linear instability) sprayatomization and new droplet collision (based onsuggestions made by Nordin, 2001) models leadsto diesel flame development at a tip of the spray(see Fig. 3a), while the combination of the

Fig. 3 Predicted temperature distributions for the following combinations: (a) KHRT+new droplet collision models and t=1.75 ms, (b) TAB+O’Rourke model,t=1.75 ms in the 3-D constant volume vessel. Initial volume parameter: P0=50 atm., T0=800 K, 6 mg of fuel (diesel oil surrogate model) was used. Injectiontime = 1.27 ms.


Fabian Kärrholm, PhD studentExperimental Physics

I am new to the spray project, started inthe fall of 2003. My first project will be toexamine different turbulence models, andhow they affect the spray. I have a MSc inPhysical Engineering with mathspecialization.

original KIVA code (TAB+O’Rourke) modelspredicts flame initiation at the side of the spray (seeFig. 3b).

The integrated computer model has been appliedto combustion simulation of the Volvo D12Cengine (six sprays) in the MK regime realizedby late fuel injection (from TDC up to 6-8 CAATDC) and compared with experimental dataprovided by T. Rente in her thesis InjectionStrategies for Heavy Duty DI Diesel Engines.The plots presented in Fig. 4 (a-b) illustrate theresults of such a comparison for in-cylinderpressure and RoHR vs CA histories.

Finally, application of the model to the free-piston advanced energy converter (based ondiesel spray combustion) is presented in Fig. 5,illustrating its applicability to future enginesystems under development.

References 182 - 189 from this project werepublished during 2004.

Fig. 4 Predicted in-cylinder pressures (a)and RoHR vs CA histories (b) comparedwith experimental data for a Volvo D12Cengine with fuel (25 % load) for differentSOI.

Fig. 5. Wall temperature distributions(under adiabatic conditions) in the “free-piston” hybrid engine based on currentdiesel spray combustion technology.


BackgroundIn order to reduce the environmentalimpact of global warming caused byautomotive prime movers, the ACEA(Association des Constructeurs Europeand’Automobile) has committed itself to cutCO2 emissions to 140 g/km (fleet average)by the year 2008 and to assess in 2008 thepossibilities of a further reduction to 120g/km CO2 by the year 2012.

One way of reducing fuel consumption andCO2 emissions from an SI engine is to useGasoline Direct Injection (GDI). The GDIengine can operate in several differentmodes:

At low and medium loads, the engineoperates in stratified mode, in which heatlosses can be reduced by operating theengine globally lean. Also, by running theengine unthrottled at low loads, thepumping losses can be reduced.

At high loads, the engine operates inhomogenous mode. A higher compressionratio than is possible in a PFI engine canbe achieved, due to charge cooling by thelatent heat of the fuel.

Direct injection engines can also beoperated in homogeneous mode across theentire load and speed domain, withsignificant amounts of EGR at low loadsand engine speeds.

Another benefit is that engines’ cold startcharacteristics can be improved as GDIallows better control of the ignition process.Furthermore, using DI the ratio of specificheats will be higher than in homogenouscombustion.

The design of a GDI system is a verycomplex task. The main difficulty lies inthe fact that it is necessary to have anignitable (stoichiometric or slightly rich)mixture near the spark plug at the time ofignition, regardless of the engine speed andload. At the same time, it is crucial to keepthe fuel mixture from hitting the piston orcylinder walls to prevent excessive UBHCemissions.

In recent years three different types of GDIsystem designs have surfaced:

Wall-guided systems. A surface(normally the piston top) is used todirect the fuel mixture towards thespark plug. This is the most commontype of GDI system today and severalcar manufacturers have such systemsin production. Previous work,

Ingemar Denbratt, Professor,

Project Leader

Petter Dahlander, AssosiateProfessor

Mikael Skogsberg, Ph.D student

Ronny Lindgren, Ph.D student

Petter Dahlander, Researcher, Ph. D,Thermo and Fluid Dynamics

I have a got a PhD in CFD at Thermo andFluid Dept., Chalmers, and started workingwith this project in November 2002. I willbe working both with experiments andsimulations of sprays and combustion.

Spray-Guided Gasoline Direct Injection

however, has shown that the gainsin fuel consumption and CO2emissions are considerably lowerthan those theoretically possible (10-15% as compared to the theoretical25% gain). Also, wall-guided systemshave been shown in a previous CERCproject (see below) to produce highamounts of unburned HC and sootemissions, mainly due to poormixture stratification at low loadsand ineffective mixturehomogenization at high loads.Furthermore, the speed/load area inwhich stratified operation is possibleis limited in a wall-guided system.

Air-guided systems. A well-definedgas motion (tumble) is used totransport the air and fuel mixture tothe sparkplug. The geometry issimilar to the wall-guided system, i.e.wide spacing. However, thecombustion is very difficult tooptimize for all loads and speeds.This combustion system must beconsidered as the least likely to beintensively pursued in the future.

Spray-guided systems. The mixtureformation is not dependent on asurface or the in-cylinder air motionto control the stratification. The fuelspray is ignited at the periphery by aspark plug located close to theinjector; at most around 20 mm fromthe injector. Consequently thisconcept is called close spacing. Sincethe fuel concentration gradient alongthe periphery of the spray is verysteep, the spray has to be very stable,regardless of the in-cylinder pressureconditions. This combustion systemis therefore more sensitive than a wall-guided system to injector tolerancesand mounting tolerances. Spray-guided systems have given reportedimprovements in fuel consumption ofaround 25% with relatively low HCemissions, compared to MPFI. Thesoot emissions are comparable tothose obtained with wall-guidedsystems. A major advantage with aspray-guided system is that thestratif ied operating area isconsiderably larger than for a wall-guided system.

This project was initiated in Jan 2002 as acontinuation of a CERC project started in1997 regarding emissions and depositformation in a wall-guided stratified-chargegasoline engine at Chalmers. The previousproject was run under the supervision of

Ronny Lindgren, Ph. D Student,Thermo and Fluid Dynamics

I completed my Licenciate examine in2002 and started in this project inNovember 2002, primarily working withnumerical simulation of spray formation.


Mikael Skogsberg, Ph. D Student,Thermo and Fluid Dynamics

I started working with this project inJanuary 2002 after I got my MSc degree atMechanical Engineering at ChalmersUniversity of technology.

project leader Prof. Ingemar Denbratt andconducted by Dr. Håkan Sandqvist, nowemployed at Volvo Car Corp. The projectresulted in a Ph. D thesis: Emission andDeposit Formation in Direct InjectionStratified Charge SI Engines, ISBN91-7291-075-5.

The sGDI project objectives are

To assess the possibilities andlimitations of spray-guidedcombustion system concepts (closespacing)

To investigate high pressure (multi-rifice) and air-assisted injectors

To establish design criteria for sucha system regarding injectors,geometries and operationalparameters.

The research strategies for this project areto combine experimental work withsimulations iteratively.

Summary of resultsThe spray formation and the consequentspray distribution from direct injectionnozzles are of paramount importance tospray-guided gasoline DI combustionsystems. Since neither support walls (suchas the piston crown) nor in-cylinder air flowis used to control the mixture quality, theinjector itself has to be able to create andmaintain a coherent, ignitable cloud of fuelmixed with air within stoichiometric limitsat the time of ignition within the reach ofsparks generated by the spark plugelectrodes.

Therefore, the work in the sGDI project hasfocused on characterizing sprays fromdifferent gasoline DI injector types toimprove our understanding of the scopeand limitations of spray-guided combustionsystems.

Results with multi-hole nozzlesThe first experiments made using a 6-holesymmetrical multi-hole nozzle operating at100 bars fuel pressure indicated that thistype of injector results in too longpenetration, as the results showed thatmuch of the injected fuel impinged ontothe piston crown, as can be seen in Figure

1, creating potentially high UBHCemissions.

In order for the injector to be usable in aclose-spacing arrangement typical of spray-guided stratified operation, it must providea mixture, at geometrically feasible sparkplug positions, that promotes stable ignitionand flame propagation.

Consequently, LIEF measurements wereperformed in order to qualitativelydetermine and distinguish between gas andliquid phases of the fuel, to identify suitablespark plug positions, and to find ways tominimize liquid fuel penetration. In orderto isolate the phenomena caused by theinjector from the external environment, theinjector was mounted in the High-pressure/High temperature spray chamber.

Figure 2 shows qualitative time-resolvedresults from measurements made atchamber conditions of 10 bar/584 K. Theresults have been processed so that thevapor concentration is illustrated by theheight along the z-axis, and the liquidconcentration is represented by the color.The general sequence of events observedin the LIEF experiments is illustrated in theimages in Fig. 2, which show:

A. The quiescent air in the spray chamberis being displaced by the spray head. Freshair is being entrained at A-1 as a result oflow static pressure caused by the spray’smotion. The vapor phase is contained withinthe liquid phase because the onlymechanism transporting vapor away fromthe liquid phase at this time is diffusion,which is comparatively slow. The air motionat A-3 is low.

B. The axial velocity at B-3 is still relativelylow. Fresh air is still being entrained intothe spray at B-1. This effectively keeps thevapor phase contained within the liquidphase close to the nozzle because theconvection caused by the inwards-movingair is stronger than the diffusionmechanisms which act to push the vaporaway from the liquid. At B-2, a vortex causedby the propagating spray transports vaporaway from the liquid fuel.

Figure 1. Direct imaging results obtainedusing the 50-degree multi-hole nozzlemounted in the optical engine, showingthat the extent of liquid fuel penetrationneeds to be reduced in order to avoidexcessive UBHC emissions since a largeproportion of the injected fue l hits thepiston. The amount of liquid fuelimpacting on the piston could be reducedby heating the intake air, thus promotingits evaporation. Images captured at 335CAD. In-cylinder conditions: 8.2 bar/516K (left image), 7.9 bar/600 K (rightimage).


C. As the injection event progresses, theaxial velocity at C-3 continues to increase,which lowers the pressure at C-3. This staticpressure is now low enough to change theoutwards-rolling vortex into an inwards-moving motion which prevents vaportransport away from the spray cone at C-2.Instead, the pressure at C-3 is low enoughto force the spray at C-2 to start moving inthe opposite direction, effectivelydecreasing the umbrella angle.

D. Injection has ended and traces of post-injection can be seen. The resultingcombustible vapor cloud resides within theumbrella angle of the spray.

The following conclusions can be drawnfrom the above observations:

• Close to the nozzle, vapor is onlyfound in the presence of liquidthroughout the injection.

• At an axial distance of 20 mm fromthe nozzle, the outwards-rollingvortex separates combustiblevapor from the liquid phase of the

Figure 2. Two-phase visualization of a spray using the LIEF technique. The vapor concentration is represented by the height along the z-axis which shows theintensity count of the 8-bit image (0-256). The liquid concentration is indicated by the color.

A B

C D

fuel. Unfortunately, a point at thisdistance would not be a suitablelocation for a spark plug as thedistance between the pistoncrown and the nozzle is less than20 mm in an engine.

• When the injection duration islong, the high axial spray velocitylowers the pressure inside thespray. This prevents vaportransport away from the spray atB-2, and thus reduces the injectorumbrella angle.

These three conclusions, in combinationwith those drawn from the optical enginemeasurements, indicate the need for furtherrefinement of this multi-hole nozzle designin order to ensure appropriate ignition andflame propagation of the mixture occurwithout high UBHC emissions.

The LIEF results presented in Figure 2showed that one of the causes of the spray’sover-penetration was that its umbrella anglewas too small. The small umbrella angle


was also found to cause very sharp air/fuelratio gradients at its outer edges, effectivelylimiting the possible spark plug locationsdue to the risk of wetting the spark plugwith liquid fuel, which can cause misfiring.

Therefore, numerical simulations were doneto find possible ways to reduce both thepenetration and air/fuel ratio gradients nearthe spark plug location. The results, asshown in Figure 2, indicated that the spraypenetration could be reduced if theumbrella angle was increased. Furthermore,the asymmetrical shape of the spraypromoted air entrainment and therebypromoted vapor transport towards the sparkplug, as shown in Figure 3.

Moreover, both results from simulations(Figure 3) and experimental results, shown

in Figure 4, support the hypothesis thatalthough suitable spark plug positions aredifficult to find on the outer edges of thespray plumes from multi-hole nozzles,suitable spark plug positions may be foundbetween adjacent spray plumes.

As well as the geometrical positioning ofthe holes on the injector tip, the effects ofvarying the parameters of the holesthemselves have been studied. The typicalhole on a multi-hole injector can be seenas a cylindrical orifice of length, l, anddiameter, d. A measure of the geometricalproportions of the hole is therefore the ratiobetween the injector hole length anddiameter, l/d.

In order to study the effect of differentorifice geometries, injectors with varying l/d ratios were tested in the high-pressure/high temperature rig. A first study usingthe direct imaging system from AVL® wasundertaken to measure spray angles andspray penetration and to optically determinethe influence of boundary conditions suchas chamber density and back-pressure onthe spray formation.

Later, PDA measurements were performedin order to quantitatively determine the dropsizes and velocities from holes with differentl/d ratios.

The experimental results indicated that thedrop sizes generally decreased as thediameter of the holes was reduced.Furthermore, the effect of reducing theinjector hole sizes in terms of drop sizeswas insignificant compared to the influenceof boundary conditions such as back-pressure and temperature.

One interesting finding that was establishedusing the PDA system was that the dropsize distribution was different for holes ofdifferent diameters. For small holes, theprobability of large drops (drops with adiameter exceeding 8 µm) being generateddecreased significantly.

Since the mass of a drop is proportional toits size, a large drop has higher momentumthan a small drop and consequentlypenetrates further. Also, larger drops needmore time to evaporate due to their smallersurface area to volume ratio. Therefore, theprobability of large drops forming may bea measure of the potential for wall wettingand UBHC emissions.

Figure 2. Numerical simulations show that the spray penetration can be reduced by increasing theumbrella angle.

Figure 3. By positioning the nozzle holes asymmetrically, the resulting vapor cloud is steered towardsthe spark plug location. The image to the right is a planar representation of the conditions betweentwo spray plumes and is a snapshot at approximately 0.3 ms after the end of injection, which maybe a suitable ignition timing for the tested case.


Another valuable finding is that the sprayangle decreases as the l/d ratio increases.This means that the l/d ratio can be usedas a control parameter for the sprayformation. By reducing the hole diameter,thereby increasing the l/d ratio, the sprayangle can be reduced.

Figure 4. MIE/LIF image in a plane between two sprayplumes indicating a large vapor cloud without liquidinterference at 0.3 ms after the end of injection. Thegray areas represent vapor, while the white areasinside the vapor cloud indicate the presence of liquid.

Also, an investigation of the influence offuel pressure on the spray formation formulti-hole nozzles has been performed. Theresults will be published in an upcomingpaper. Figure 5 shows an example of theresults.

Experimental results with air-assisted nozzlesAn Orbital air-assisted injector was testedin order to gain further knowledge aboutthe physical properties of sprays used forspray-guided gasoline DI combustionsystems. The parameters of interest werethe spatial fuel distribution, spraypenetration, spray evaporation rate, dropsizes and drop velocities.

In order to evaluate the abovementionedparameters for the air-assisted injector,direct imaging, PDA, Mie, and LIFmeasurements were taken in the high-pressure/high temperature rig.

The results show that for the air-assistedinjector, the mass of injected fuel has a majorimpact on the spray formation. As the injectoropens outward and the injector tip isdesigned to stabilize the spray at low loads,the spray cloud is kept together by a spray-induced wake downstream of the nozzle,creating a spray pattern as shown in Figure 6.

At higher injected fuel masses (higher loads),the momentum of the injected fuel is highenough to make the spray separate into a

Figure 5. Results from PDA measurements with a multi-hole injector takenat different fuel pressures.

Figure 6. AVL Visioscope single-frame images of events at 0.73, 1.15 and1.9 ms ASOI. The images were obtained at 2.5 bar chamber back -pressureand 384 K temperature. PDA data velocities are shown superimposed onthe images. Units in mm.

Figure 7. AVL Visioscope single-frame images of events at 0.73, 1.15 and1.9 ms ASOI, for chamber conditions representing full load: chamber back-pressure 1.3 bar, temperature 295 K. Units in mm.

hollow cone shape with an umbrella angleof 100 degrees, as can be seen in Figure 7.

Furthermore, a spray-induced vortexgenerated by spray pulsations (enhancedby the low injection rate) was found toincrease air entrainment into the spray. Theincreased air entrainment raised theevaporation rate. This can be seen in Figure8, in which the dark areas show vaporizedfuel devoid of liquid. However, theevaporation rate was still generally low,even at higher chamber back-pressures andtemperatures, prompting speculation that


the low evaporation rate may be caused bypoor atomization.

To test this possibility, PDA measurementswere conducted at different chamber back-pressures and temperatures and the resultsshowed that the atomization was, on thecontrary, quite good, with a mean dropletsize of 8-11 µm. Instead, the evaporation ratewas found to be low because the fuel iscontained within a cold air jet.

This air jet consists of the pressurized airthat is injected by the injector itself, andwas supplied at room temperature duringthe experiments. Therefore, the evaporationrate is likely to be higher in real engineapplications, where the pressurized airsupplied to the injector is pre-heated bythe engine as the air supply lines are thenpackaged within the engine cylinder head.

The cold air jet surrounding the fuel wasalso found to promote the spray’spenetration. This is because the fuel andair have low velocities relative to each other,which effectively reduces the drag and shearforces on the drops and consequentlyreduces secondary break-up.

Thesis projectsIn further work during 2003, a cylinder headwith optical access allowing variable sparkpositioning has been designed andmanufactured. This was done as a thesisproject by Erik Larsson, an undergraduatestudent at Chalmers. In addition, twodifferent pistons with optical accessallowing two different compression ratioshave been designed and manufactured.Furthermore, a second thesis project,performed in 2004 by Joakim Kindströmresulted in a variable swirl/tumble systemfor use in conjunction with the modifiedcylinder head. PIV measurements have beentaken to evaluate the results of different

swirl/tumble settings on the in-cylinder airflow of the engine.

Future ResearchMuch work remains to be done before thesGDI project is concluded. Notably, mostof the work done so far has been focusedon operating the engine in stratified mode.However, this operating mode is feasibleonly for low to medium loads and speeds.It is equally important for spray-guidedcombustion systems to allow robust,efficient and clean operation in the higherload and speed areas too, in which theengine operates with a homogenous charge.

In order to study the injector characteristicsin homogenous mode, measurements areplanned in the near future to study the sprayformation at low chamber temperatures andpressures, providing similar operatingconditions to an engine operating withinjection in the intake stroke running at fullload. Specifically, flash boiling behavior ofsprays at very low chamber pressures (< 1bar) will be studied using high speedphotography.

In parallel, validation of the numericalresults gained in the sGDI project willcommence. Measurements using Mie, LIFand PDA to characterize the spray formationfrom asymmetrically positioned holes ofmulti-hole injectors have been obtained andthe data will be carefully analyzed in thenear future.

The long term outlook is to use our custom-made cylinder head, which allows the sparkplug positioning to be varied, to furtherinvestigate the combustion robustness andphysics of the spray-guided injectors in theoptical engine.


Figure 8. Results from single-frame Miescattering, superimposed onsimultaneously captured LIF images at1.15 and 1.9 ms ASOI. The gray areasindicate areas with only vapor, and noliquid present. PDA velocity vectors arealso superimposed. Units in mm.


Important goals for combustion engineresearch are to develop combustion systemswith low fuel consumption and reducedemissions of NO

x, CO, hydrocarbons and

particulate matter to meet present andfuture emission regulations, and reduce CO

2

emissions. It is difficult to apply allcharacterization techniques in real engines,so experiments are also done in variousmodel systems such as single-cylinderengines with optical access or hightemperature/high pressure cells withconditions similar to those in a combustionengine. Various laser spectroscopictechniques are very useful tools forinvestigating combustion and combustion-related processes. Lasers providemonochromatic light with high intensityand short pulse lengths, allowing individualcombustion species to be detected withhigh time resolution. Furthermore, whenCCD-cameras are used for the detection,two-dimensional imaging with good spatialresolution can be achieved. Similarly, fuelsprays can be visualised by illuminating thespray with laser light and monitoring theabsorption, deflection, scattering or inducedemission. In order to perform suchspectroscopic studies with good accuracyit is necessary to acquire test and calibrationmeasurements of the absorption, emissionand scattering efficiency of the variousspecies in well-defined reference systemssuch as gas- or liquid-containing cells orflames. The goal of the optical two-phasediagnostics project is to extend our earlierstudies of dense sprays, especially usingMie-scattering, to develop techniques forparallel imaging of the distribution of fuelin the liquid and gas phases. The feasibilityof using other techniques is also beingtested in diploma projects.

The goal of the laser-based spectroscopystudies is to extend our knowledge from amacroscopic through microscopic to anano- or molecular understanding, whichalso requires extension of theoreticalanalysis from computational fluiddynamics, CFD, to molecular dynamics, MD.Use of spectroscopic methods providesopportunities not merely to characterize thespray and to study species created in thecombustion, but also to monitor the speciesand changes in flame fronts (and otherfeatures) with time during injectionsequences. The information acquired, andtechniques developed, will allow moredetailed two-, or even three-, dimensionalcharacterisation of the spray and the effectson the combustion species of key variables

of the injector such as the hole diameter d ,

the injector length l , fuel temperature 0T ,

Optical Two-Phase diagnistics

fuel injection pressure Pinj

and conditionsin the combustion volume such as thepressure P and temperature T . The resultscan then be used to calculate the normallyused macroscopic parameters such as thepenetration length, L , and the cone sprayangle, θ .Improved understanding of the investigatedsystems can be obtained by comparingresults from experimental studies withresults obtained from theoreticalsimulations, as discussed in general in arecent article in Physics Today, January2005, p 35-41. Results from such anapproach are very valuable not only forthe technical improvement of existingengines, but also for the development ofnew engines and provide a sound basis forvalidation and improvement of the sprayinjection systems and combustionprocesses.

Laser-based methodsTwo commonly used methods for sprayimaging are Mie-scattering and laser-induced fluorescence (LIF). Mie-scatteringis an elastic scattering process, i.e. thewavelength of the scatted light from smallparticles or droplets is the same as that ofthe incoming laser light. Since the crosssection for Mie scattering is much higherthan that of scattering from individualmolecules (Rayleigh scattering), thescattered light will almost exclusively comefrom fuel droplets. In LIF a fluorescenttracer molecule is added to the fuel, and ifthe tracer co-evaporates with the fuel,images of the fuel distribution in both theliquid and gas phases are obtained. In orderto get reliable results it is important for thetracer and the fuel to have similar physicalproperties. Commonly used tracers for LIFimaging of fuel sprays are ketones. If twosimultaneously recorded Mie- and LIF-images are compared, the penetration ofthe liquid phase can be determined andareas with only gaseous fuel identified.However, in areas where both gaseous andliquid fuel are present, the relativeabundance is difficult to determine.Furthermore, quantification is complicateddue to multiple scattering in dense sprays,variations in scattering efficiency withdroplet size, and the fact that thefluorescence quantum yield depends onpressure and temperature and is affectedby collisional quenching.

Another method of increasing popularityin combustion studies is laser-inducedexciplex fluorescence, LIEF. In LIEF the fuelis doped with two compounds: a monomer,M, and a ground state reaction partner, G.The injected laser light excites M to a higher

Arne Rosén, Professor

Mats Andersson, Assosiate

Professor

Fredrik Persson, Ph.D Student

Stina Hemdal, Project Student

I joined CERC in 2003, but have for severalyears used various spectroscopic methodsto investigate atoms, molecules, clustersand nanoparticles. For a spectroscopist,combustion science offers stimulatingchallenges in setting up experiments toinvestigate the distribution in space andtime of various species inside chambersor engines, which are not always easy toaccess optically. To our help we havesophisticated equipment such as high-power lasers, CCD-cameras andspectrometers, and it is very rewarding tosee how our efforts can contribute toincreased knowledge about the complexprocesses of spray formation andcombustion. For a physicist, it is interestingto work within combustion science, whichconnects several disciplines and requiresthe understanding of phenomena both ona molecular level, and on a macroscopicscale.

Mats Andersson, Ass ProfExperimental Physics


energy level. When the excited monomer,M*, collides with G they react and form anexcited state complex: the exciplex, (MG)*.The proximity of the molecules leads torapid exciplex formation in the liquid phase.Therefore, the exciplex will mainly beformed in the liquid phase, while excitedmonomers in the vapor do not undergocomplex formation. Since the fluorescencefrom the exciplex is red-shifted comparedto the fluorescence of the monomer, thelight emitted from the liquid and vapor canbe spectrally separated and visualized by apair of CCD cameras with appropriatewavelength filters. The LIEF method has thesame high sensitivity as ordinary LIF butalso the same weaknesses, i.e. LIF and LIEFare dependent on temperature, pressureand quenching. The benefit of using LIEFinstead of simultaneous LIF and Mie

measurements is that the monomerfluorescence, when using LIEF, only givesinformation on the gas phase, while LIFmonitors the fluorescence from both theliquid and vapor phases. A schematicoverview of the processes involved in sprayimaging with LIEF is shown in Fig. 1.

Measurements in the high-pressure/high temperature cellIn collaboration with the sGDI project Mie-LIF and LIEF measurements are preformedin the high pressure and high temperaturespray cell. The experimental set-up for thesemeasurements is shown in Fig. 2. Theincoming laser light is spread out in a thinlaser-sheet that enters the chamber. Theoutput signal is divided by a beam splitterand detected by two ICCD cameras. Filters

Figure 1. After excitation by laser radiation the red-shifted exciplex fluorescence comes from the liquid part ofthe spray while monomer emission is dominant in the less dense vapor regions. Therefore it is possible toseparate the fluorescence originating from the two phases.

Figure 2. The experimental set-up for spray imaging in the high temperature and high-pressure chamber.

Stina Hemdal, Project Student,Molecular Physics

Personal Stina HemdalI am working with Cavity RingdownSpectroscopy quantitative measurementsof radicals application to calibration ofLaser-Induced Fluorescence. I am alsoworking with optical two-phasevisualisation of fuel sprays together withFredrik Persson and the supervision ofMats Andersson.


Figure 3. Images of different sprays in the high temperature/pressure cell recorded using the Schlieren, Shadowgraph, Mie/LIF and LIEFspectroscopicmethods.**


in front of the cameras separate thescattered light and the different types offluorescence. In order to compensate forthe pulse-to-pulse fluctuations of the laserpower and the intensity distribution a smallfraction of the laser sheet is directed to adye-containing cell. The fluorescence signalfrom the cell is then captured beside thespray image by one of the cameras.

In addition to the LIEF and LIF/Miemeasurements, exciplex and Mie signalshave been simultaneously captured,allowing direct comparison of the signalsoriginating from the liquid phase. In Fig. 3spray images captured with different laserdiagnostic methods (Schlieren,Shadowgraph, Mie-scattering, Laser inducedfluorescence, Laser induced exciplexfluorescence and corresponding monomerfluorescence) are shown. The differentmethods capture the distribution of fueleither in both the liquid and vapor phasesor in just one of them. The evolution of thetotal fluorescence intensity as a functionof time ASOI for LIEF-monomer and Mie-LIF is shown in Fig. 4. The graphs showthat there are differences between theexciplex and monomer intensities, whilethe LIF and Mie signals follow each othermore closely, demonstrating that LIEF hasgood potential for discriminating betweenthe signals from the liquid and vaporphases.

Figure 4. The total fluorescence intensity as a function of time. The top image shows thedifference between the exciplex (fluorobenzene + triethyl amine) intensity (blue) and the monomerintensity (pink). The lower image shows the intensity of the Mie signal (black) and the 3-pentanone LIF (red).

Figure 5. Mie scattering from falling droplets in thehigh pressure/high temperature chamber. The 3-pentanone doped iso-octane droplets have also beenimaged with the LIF technique.


Spectroscopic studiesEarlier, several exciplex solutions, bothestablished and novel, have been evaluatedby recording emission and excitationspectra. The monomer and exciplexemission wavelengths have been studiedat room temperature and ambient pressureusing a Cary Eclipse fluorescencespectrophotometer. The different dopantsthat have been tested and some results ofthese studies can be found in Refs. 1 and2. These spectroscopic studies areperformed in order to find dopants thatgive good spectral separation and havesimilar physical properties to the fuel usedwith respect to boiling point, vaporpressure and density. Initial measurementsof the temperature dependence of theemission spectra showed that even a smallchange in temperature affects thefluorescence signal. In order to improvethe study a special cell-holder has beendesigned and constructed so that thedifferent solutions can be heated to theirrespective boiling points in a controlled wayinside the spectrophotometer.

Simultaneous Mie LIFmeasurements for average dropletdiameter investigationsIf the diameter, D , of the droplets ensemblein the spray is much larger than the

wavelength,

λ

, of the light, i.e.

, then the intensity of the Mie-scattered signal from a droplet of diameter

can be expressed as .If it can be assumed that the incoming lightilluminates the whole droplet volumeuniformly then the intensity of the LIF

signal is given by .If the LIF signal comes from the liquidphase then the ratio of the measuredfluorescence and the Mie signal is a quantitythat scales proportionally to the diameterof the droplets. The ratio of the LIF and

Mie signals is related to the Sauter meandiameter (SMD

32) of the droplets

by the function

[Laser Sheet Dropsizing of dense sprays”,P. Le Gal,N. Farrugia, D.A. Greenhalg, Opticsand Laser Technology 31 (1999)]. To obtainabsolute values of SMD the value of K hasto be determined by calibration. It shouldbe noted, however, that this method onlygives the average diameter of the droplets,and does not provide information about thesize distribution. We have done somepreliminary studies of droplet generationusing a standard spray injector in the highpressure and high temperature cell.

Intensity measurements ondropletsWhen analysing spray images, calibrationof the experimental data is extremelyimportant, not only to determine featuressuch as the boundary between the sprayand the background, but also in the longterm to measure the concentration ofsprays. Therefore a first step was toconstruct a droplet-generator that could bemounted in the high-pressure/high-temperature chamber. A Mie scatteringimage of droplets is shown in Fig. 5. Fromthese images, spectroscopic properties likethe fluorescence intensity from a dropletwith known concentration andspectroscopic properties like fluorescencesaturation and emission band overlap whenapplying the LIEF technique could bedetermined. In addition, physical factorssuch as droplet evaporation with differenttracers and fuel can be investigated. Ifdroplets with well-known size can begenerated, such information can be usedto calibrate droplet size measurements asdescribed above.

Figure 6. Schematic diagram of the experimental set-up for the Cavity Ringdown measurements with an atmospheric flame.

Fredrik Persson, Ph.D. Student, MolecularPhysics

I am working with laser diagnostics and withLaser Induced Exciplex Fluorescence (LIEF)in particular. It is interesting and challengingto study fundamental physics and then toapply spectroscopic research in engines. Inspite of the fact that LIEF was used as earlyas the middle of 80’s, a lot of questionsremain to be solved before the method isreliable. For example, what is the behaviourat higher temperatures, can we be sure thatit is only the liquid phase that we see andthat there is no disturbing monomerfluorescence?The advantage with using laser spectroscopyin combustion diagnostics is mainly that itis a non-intrusive method and that it ispossible to use the laser-diagnostic techniquefor many different purposes like Ramanscattering and Laser Induced fluorescence.

D


Figure 7. Absorption as a function of height over theburner for the blue and yellow flames, and photos ofthe flames with the measurement zone marked.

Quantitative measurements usingCavity Ringdown SpectroscopyAnother important task in LIF and LIEFinvestigations is calibration, in order toobtain valid quantitative measurements.. Cavity Ringdown Spectroscopy (CRDS) isa multi-pass absorption method with highsensitivity that is suitable for measurementsof transient species in combustion studies.Previously we have used LIF to measurethe OH concentration outside a Pt foil in acombustion chamber. The combination ofLIF and CRDS provides a quantitativedistribution of the target radical and wasused in this study to analyze the quenchingof the LIF signal due to water produced ina catalytic reaction [3]. In our CRDSexperiments we have achieved ppm-levelsensitivity. However, using state-of-artmirrors and lasers sub-ppm sensitivitywould be achievable.

Cavity Ringdown measurements of sootIn the past year we have started to applyCRDS to soot measurements in anatmospheric flame [4]. In our experimentslaser light with wavelengths around 497nm is aligned with the optical cavity. Anatmospheric flame is placed in the centerof the cavity. Due to the very highreflectivity of the mirrors only a smallfraction of light is transmitted in eachroundtrip through the cavity. A photo-multiplier tube detects the transmitted lightat the output mirror as a function of time.A schematic diagram of the experimental

setup is shown in Fig. 6. In order todetermine the losses due to soot absorption,the decay time for a non-sooting (blue)flame is compared to the decay time for asooting (yellow) flame. Typical absorptionvalues for the blue and yellow flames as afunction of height are shown in Fig. 7. TheCRDS results are going to be compared toextinction measurements obtained from thesame system and a further intention is toapply the method to calibration of laser-induced incandescence (LII).

OutlookWe will continue our work on characterisingthe fluorescence properties of tracermolecules, especially combinations ofexciplex-forming tracers. With our new cellholder we have the possibility to investigateliquid samples at elevated temperatures.Reference measurements in cells or ofindividual droplets will be critical forselecting the best tracer combinations andconcentrations and detection wavelengths,as well as for a more quantitativeinterpretation of the results. In theevaluation of spray images we will focuson the possibilities and limitations of LIEFto identify how the fuel is distributed inthe liquid and vapor phases.

The next step for the CRDS project is toapply the method for calibrating LII. Wealso want to use the method for in situmonitoring of exhaust species, measuringppm levels of radicals and soot. These kindsof experiments may best be done incooperation with participants in theNanoparticle project.



Theoretical and Experimental Investigations of Combustion of ShortDuration Small Diameter Sprays in Diluted Air

BackgroundThe main objective of this project is toinvestigate how best to utilize multipleinjections in order to reduce emission, andthus meet the increasingly strict emissionlegislation for diesel engines. A multipleinjection is an injection that is split into twoor more injections. Distinctions are madebetween pilot, post (sometimes called preand after injections) and split injections. Apilot injection is a short injection thatprecedes the longer main injection. A postinjection is a short injection that comes afterthe main injection. A split injection is simplyan injection split into two parts, but forwhich neither the terms pilot nor post areappropriate, it is something in between. Inits simplest form a multiple injection consistsof only one main injection together withone pilot or post injection. A more complexmultiple injection consists of a combinationof various injections. When multipleinjections are applied it follows that theconditions for the subsequent injections willnot be the same as for the first injections.This is because of the combustion of thepreceding injection resulting in low oxygenlevels. Other parameters such as gas motionand temperature are also affected by apreceding injection. This could causeproblems, but it is also believed to contributeto the positive effects of multiple injections.Another phenomenon that has to beconsidered is the dynamic effects in theinjection system caused by pressurefluctuations actuated by the fast openingand closing of the injectors, which may affectthe accuracy of the injection rate.

Two papers concerning results obtainedwithin this project were presented during2004; one in July at the “Vehicles AlternativeFuel Systems & Environmental Protection”conference in Dublin, Ireland, entitled“Numerical and experimental investigationof fuel properties influence on the dynamicbehaviour of a diesel injection system” andthe other in September at ILASS-Europe inNottingham, England, entitled “Experimentalinvestigation of spray behaviour and spray

interaction for diesel multiple injectionapplication”. Most results presented herein this summary were introduced at one ofthose two occasions.

The influence of fuel properties onthe behaviour of a diesel injectionsystemDuring the experimental work within thisproject it became clear that the use ofdifferent fuels affects the results. Theinjector behaviour and transient fuel massrate were influenced by the choice of fuel.This finding is consistent with expectationsif one considers the fuel properties, whichdiffer quite substantially in some cases.Therefore, a more detailed study of theeffects of the fuel properties wasperformed. Different fuels are used inexperiments mainly for two reasons. First,the fuel must be suitable for the measuringmethod employed and second ideally itshould be relatively easy to performnumerical simulations on the fuel.Obviously, the fuel properties should alsoideally resemble those of diesel.

Diesel and n-decane were investigatedexperimentally and numerically to find outhow the dynamic behaviour of a commonrail injection system and the injectioncharacteristics were affected by the choiceof fuel in general and for multiple injectionsin particular. The experiments showed thatthe mass rate was 8 - 9 percent lower forn-decane than for diesel, due to the lowerdensity of n-decane, see Figure 1, left panel.The momentum of the fuel injection, onthe other hand, is not affected by thedensity and could thus be expected to beequal for the two fuels. This is alsoconfirmed by the measurements, althougha small difference is detected; Figure 1, rightpanel. As a consequence of the mass ratebeing dependent on the density while themomentum is not, it is not possible to keepboth the mass rate and the momentum ofan injection constant when going from onefuel to another with a different density.

Figure 1 Measured values of the injectedmass (left panel) and momentum (rightpanel) for 4000 µs single injections atthree different pressures; 700, 1000 and1350 bar; of diesel and n-decane.

Sven Andersson, AssociateProfessor

Rickard Ehleskog, Ph.D.Student

Rickard Ehleskog, Ph.D. StudentDepartment of Applied Mechanics

I am a Ph. D. student since 2002, and myresearch area is diesel engines, andespecially short duration injections andsmall orifice diameters. My work is mainlyexperimental but numerical simulationsare also included in order to look into andunderstand certain phenomena.When trying to find out how a dieselcombustion system works it is mostimportant to have good understanding ofwhat is happening within the injectionsystem. The natural way to work is to startinvestigating the elementary underlyingcharacteristics and systematically continuewith experiments that are more complexwhere the final goal is full-scale enginetests. Up to now, the focus has been onthe more fundamental investigations.Investigations of spray characteristics andthe dynamic behaviour of the injectionsystem has been a central part. The projectis however about to switch into the nextphase where engine test are more central.


Investigations in the two CERC projectsApplied combustion diagnostics andInfluence of cavitation and hydraulicflip on spray formation, ignition delay,combustion and pollutant formationshowed that the fuel jet momentum isthe dominant factor controlling thespray mixing and subsequentcombustion, hence the momentum ofthe injection is of importance.

Discharge coefficientThe discharge coefficient, Cd, is the ratioof the actual and maximum theoretical flowthrough a nozzle. Cd is a flow-dependentquantity, and hence is fuel specific. Thedischarge coefficient could be expressedas

Besides the pressure drop, which isunknown, the area, A, is known and theforce, F(t), caused by the jet impinging ona probe is measured. So, if the transient Cdis to be calculated the pressure in the nozzlemust be estimated. As the pressure of thespray chamber is atmospheric in this casethe pressure drop over the nozzle can beassumed to be equal to the nozzle pressure.However, the nozzle pressure is fluctuating,and in our tests is not measured, so it hasto be estimated. The simplest way is toassume the nozzle pressure is equal to therail pressure, but this generates poorestimates since there are large fluctuationsin the fuel line and consequently also inthe nozzle. A better assumption is to usethe fuel pipe pressure. Measurements showthat the fuel pipe pressure fluctuatesconsiderably, and it can be assumed thatthere are even bigger fluctuations in thenozzle since it is the origin of the pressurewaves, and the diameter of the fuel pipe islarger than the diameters of the lines insidethe injector. This has also been confirmedby calculations, using a 1D flow model forhydraulic applications. In addition the

Figure 2 Discharge coefficients – based on a rail pressure of 1350 bar (left panel), and based on an assumednozzle pressure (right panel).

pressure fluctuations in the fuel pipe aredisplaced in time relative to the nozzle dueto the distance the pressure waves have totravel between them. This means thatassuming the pressure drop to be equal tothe fuel line pressure is also invalid.Another assumption is to start with the pipepressure and translate it to a nozzlepressure by amplifying the fluctuations andmake a phase shift. In Figure 2 this hasbeen done. The graph in the left panelshows the discharge coefficient calculatedwith the rail pressure, with an estimatednozzle pressure based on the fuel pipepressure. The curves in the right panel havea slightly flatter appearance, but are stillquite rough as the high frequencies aredifficult to handle. A problem is that thereis a phase shift between the pressure inthe nozzle and the fuel pipe. Furthermore,the different frequencies have differentphase shifts. To obtain a better estimate ofthe discharge coefficient a more detailedstudy would be needed. To sum up, onecan state that the discharge coefficient isnot affected by the choice of fuel and itdoes not appear to oscillate. It is likely thatif it was possible to determine the nozzlepressure correctly it would result in almostflat Cd-curves over the entire injection.

Spray behaviour and sprayinteractions in multiple injectionsWhen two or more injections are injectedclose to each other in time they will to someextent interact with each other. The fastopening and closing of the injectorgenerates pressure waves which cause thepressure to fluctuate in the pipes of theinjection system as well as in the injector,making accurate fuel addition difficult. Inaddition, the spray following a previous onewill enter the trails of the former spray.The degree of interaction thus engendereddepends factors such as the swirl in thecylinder. A study regarding thesephenomena was performed in the high


Figure 3 LIF images of a double injection. The spray to the far left in each image is the first injection and the three other sprays are second injections withdifferent dwell times.

Figure 4 Spray penetration for a double injection.

pressure/high temperature spray/combustion rig (hp/ht-rig) using Mie-scattering and laser induced fluorescence(lif) analyses. The focus was on sprayinteraction for multiple injections, butspray behaviour during injector openingand closing was also considered. Someof the results were presented inSeptember 2004 in Nottingham at ILASSEurope ’04.

In Figure 3 images for double injections,in which the dwell time between theinjections was varied, are presented. Asthe image timing is relative to the trigsignal for each injection one could expectthree equally long sprays to appear ineach image. However, this was not thecase. In the image to the far left the spraysare captured 500 µs after trig. While thefirst injection is clear and legible, the threeother injections are barely visible. Theinjection with the shortest dwell is theone that seems to be slowest at the startof injection. There are several possiblereasons for this behaviour. One is that thefirst injection creates pressure fluctuationsin the injection system, which can havean impact on the start of the followinginjection. Another possible cause is thatthe injector amplifier may be unable torecover between the injections sufficientlyto open the injector a second time as fastas for the first injection. Stepping forwardin time, the other injections (central andright images, figure 3) gain on the first,i.e. injections coming directly after anotherpenetrate more rapidly. This is alsoconfirmed by the graph in Figure 4, wherethe penetration for a double injection isplotted, and the green curve clearly has asteeper slope than the first. The obviousreason for the faster penetration is that itis promoted by the gas motion in thechamber caused by the preceding spray.

FutureA licentiate thesis will be presented duringthe spring 2005.The project is now progressing to anotherphase in which the focus will be on enginetests and not so much on fundamental tests,i.e. spray rig studies. The results from thefundamental experiments done so far willhere play an important role, in helping tointerpret the engine test results. Theknowledge obtained from the spray studiesis also being used in the design of theengine tests. The first engine test series willinclude investigations of simple multipleinjections with only two injections, i.e. pilotmain and main post injections, in order tosurvey the effects of pilot and postinjections. Later a second engine test serieswith a new piezoelectric injection systemwill be undertaken in cooperation with theCERC project “Nanoparticles”. Additionalspray studies will also be done.

References 198-199 from this project werepublished during 2004.


Mats Viberg, Project leader

Professor

Bo Egardt, Professor

Jonas Sjöberg, Professor

Tomas McKelvey, Docent

Stefan Larsson, PhD.Student

Ingemar Andersson, PhD.

Student

Why feedback comtrol ?Internal combustion engines are used inmost of today’s automobiles. Thecomplexity of such engines is increasingas the demands on combustion efficiencyand emission levels increase. To meet thenew demands it is necessary to optimisethe performance of the engines, allowingmore degrees of freedom. To date, closed-loop engine control systems have been littleused. Instead, map-based open-loop controlstrategies are employed, based oncalibration maps that are optimized for eachpossible operating point. The cost andcomplexity of such calibration is rapidlybecoming unacceptable, and feedbackcontrol appears to be the only possible wayto further increase efficiency. Several typesof sensor for generating feedback signalshave been proposed, including devices formonitoring cylinder pressure, ion currentand crankshaft speed. This project isinvestigating the use of a crankshaftintegrated torque sensor in order to retrievethe required combustion information.Compared to the more common crankshaftspeed measurements, a torque sensor hasthe advantage of measuring at a higherderivative level, thereby circumventing theneed for numerical differentiation of thesignal, which significantly increases thesignal-to-noise ratio.

Project backgroundThe torque sensor project started in 1998,following discussions between Chalmersand ABB on the potential utility of acrankshaft integrated instantaneous torquesensor for automotive applications,especially internal combustion enginediagnosis and control. The torque sensor,named “Torductor-S”, has been developed

and supported by ABB since 1985. Theproject is progressing in the form of twoPhD student projects within the frameworkof CERC, and is financed in part by ABB,Volvo Car Corporation, CERC and CHASE(Chalmers Centre for Mechatronics andSystems Engineering). The overall goals ofthe project are to design, implement andevaluate an automatic control system ofcombustion phasing and internal EGR, withfeedback generated from the torquemeasurement.The research is interdisciplinary, based ona combination of physical modeling, controltheory and system identification techniques,thus linking electrical and mechanicalengineering.

Enginge control based on pressurereconstructionUntil 2003 the work was mostly focussedon physical modelling of the torque signal.Specifically, the model is used to describethe relation between the individual cylinderpressures and the resulting torque in thecrankshaft. The model is validated againsta 5-cylinder SI-engine (Volvo V70),equipped with a crankshaft integratedtorque sensor. The developed model isdiscussed in the SAE paper [1], whichadvocates the idea of pressurereconstruction from the torque sensor basedon the dynamic crankshaft model and asemi-physical pressure model. Using thistechnique, we have been able to estimateparameters such as the peak pressureposition (PPP) with an accuracy of the orderof a degree. This is sufficiently good forcontrol purposes. A control strategy forregulating the spark advance and the valvetiming adaptively using an extremumcontroller was also developed.

Figure 1 Diagram illustrating the stepresponse in the intake valve openingtime, with feedback control to keep thecombustion phasing (TR50) at a constantvalue. Different disturbances wereapplied at cycles 85 and 185. Theexperiment, performed on a Volvo V70engine, demonstrates that the controllercan eliminate “disturbances”, due tofactors such as variations in fuel quality.The response time is of the order of 10cycles.

The engine control field has been in myinterests since I first joined Mecel AB in1995, designing engine control systems forgasoline engines. My urge to learn moreabout the combustion process itselfand how to control it, lead me to theresearch studies at Linköping University.In 2002 I finished my licentiate thesis onionization current modeling there. SinceMay 2002 I am a PhD student at Signalsand Systems.In the torque sensor project the goal is tounderstand the torque signal in such waythat it is possible to extract informationfrom it,usable for engine control. Inparticular, the focus is set on combustionparameters suitable for combustionphasing. For me it is interesting to learnabout the possibilities and limitations ofdifferent sensor approaches, as for me inthe case of torque and ionization currentsensors.

Ingemar Andersson, Ph.D. Student,Signal Processing

Torque sensors for engine applications


The ideas were presented in [2], along witha simulation study of the spark advancecontroller.

Torque ratio conceptThe rationale for reconstructing pressuresignal properties for control had a largelyhistorical basis, and unfortunately hasresulted in a computationally demandingmethod. An interesting alternative is to usethe torque signal in a more direct fashion.To achieve this goal, a concept termedTorque Ratio was introduced in [3]. Thisincludes a measure for the combustionphasing, one of the key properties of thecombustion that should ideally becontrolled to maximise the efficiency of theengine. The concept includes a simplemathematical model of the spark-ignitedcombustion process, but it can besubstituted with models for any othercombustion process of interest. Thealgorithm produces a cylinder-specificestimate of combustion phasing on a cycle-to-cycle basis, named TR50.The torque ratio algorithm needs cylinder-specif ic torque contributions forcombustion phasing estimates. Cylinderseparation of the measured torque signalis therefore important. In [3] and [5] asimple approach is presented which doesnot consider the crankshaft dynamics. Thissimple cylinder separation approach limitsthe operating range of the torque ratio

algorithm to 2000 rpm for our engine. Amore complex approach to cylinderseparation, including the effect of thecrankshaft dynamics, is presented in [4].The proposed technique has givenpromising results with measured data, andwill be implemented in the real-time controlsystem during 2005.

Real-Time controlAn experimental real-time control systemhas been implemented and tested with theVolvo V70 engine ( See figure 1 & 2 ). Theproposed spark advance controller hasbeen verified using cylinder pressuremeasurements. In addition, a controllerbased on the torque-ratio based combustionphasing measure TR50 has been verified[5], but so far only using a stiff crankshaftmodel (i.e. up to 2000 rpm). Our main goalsfor 2005 are (i) to extend this to higherengine speeds based on the method of [4];and (ii) to implement an extremum-seekingcontrol approach, for adaptively adjustingthe combustion phasing setpoint. Theultimate goal is to maximize the efficiencyof the engine. We also plan to investigatethe full control structure, which includes aVVT controller for adjusting the internalEGR.


Figure 2 Diagram illustrating the cylinderbalancing capabilities of the feedbackcontroller. At first, the conventional mapbased ignition angle was utilised,resulting in large variations in themeasured TR50 among the variouscylinders. At cycle 85, the feedbackcontroller was applied. The controller isclearly able to reduce the TR50variations, by applying cylinder-individualignition angles.

Stefan Larsson, Ph.D. Student,Control Engineering

I started my career in the automotiveindustry by doing my Master’s thesis atVolvo Truck Corporation in Göteborg,working with vehicle dynamics. I initiatedmy PhD studies in October 2000 and gotthe opportunity to obtain knowledge aboutengine combustion from John Heywoodhimself during a week at MIT in Boston.This gave me a glimpse of the complexnature of the combustion. I realised thatthe techniques needed to tame the engineusing control systems can be very intricate.In June 2003 I got my Licenciate degreeafter writing a thesis about controlapproaches and system inversion. Sincethen I have been aiming towardimplementation of the control algorithms.With the help of a Master’s Thesis projectwe are writing an entire dedicatedapplication for evaluating controlalgorithms and data acquisition. The actualimplementation is something that I thinkis necessary to make the theoreticalresults trustworthy. With successful resultsthe project wil l show some of thepossibilites that a strategically placedsensor in combination with better controlalgorithms can result in. Hopefully theengine manufacturers will adopt the newcontrol strategies and improve their ownengine efficiency.


Nanoparticles

BackgroundDiesel exhaust particles consist of solidcarbon spherules with irregular shapesagglomerated in chains or clusters onwhich various hydrocarbons, sulphatesand water have condensed. Particlesrange in size from a few nanometersto 10 ?m. Nanoparticles are, bydefinition, particles with a diameter lessthan 50 nm. Particles larger than 50 nmare characteristic of the accumulationstage, which mainly consists ofagglomerates formed duringcombustion. With techniques like theuse of small-diameter, short-durationsprays or modulated kinetics (lateinjection) very low soot emissions canbe obtained, but measurements haveindicated that the number ofnanoparticles increases. This isprobably due to the very shortformation time of the particles, whichare mostly in the nucleation and earlyagglomeration stages. Also,condensation of volatiles, which occursduring the dilution of the exhaust priorto the particle measurementssignificantly contributes to themeasured nanoparticles (HC-emissionsseem to correlate with the number ofnanoparticles). The low soot dieselcombustion techniques currently beingdeveloped are all based on the fact thatat low temperatures, regardless of theequivalence ratio, or under very richor lean conditions, no soot will beformed. However, it is not known howthe size distribution of the formedparticulates is affected by thetemperature and equivalence ratio.

Figure 1. Sketch of the Raylixexperimental setup. Cour tesy ofJanbernd Hentschel at the Institut fürChemische Technik, Karlsruhe University.

Other sources of nanoparticles fromengines can include the engine lube oiland fuel sulphur.

Exhaust particles have gained theattention of research groups due to theenvironmental and health issuesassociated with them. These particles aresmall enough to be drawn into the lungsby breathing and to be trapped in thealveoli because of the incapacity of theupper airways to filter them; therebyincreasing the risk of pulmonarydiseases developing.

Research descriptionThis project is about understanding theformation and behaviour of these smallparticles. Of special interest is to studyhow new injection systems and injectionstrategies (especially short-duration,small-diameter sprays and multipleinjections) can influence the amount andproperties of the particle emissions. Inaddition, the possible effects onemissions will be investigated of usingfuels other than standard diesel (forinstance mixtures of diesel andvegetable oil esters), fuel additives andsulphur additions. The investigationswill be carried out in both researchengines and spray rigs using standardmeasurement methods as well asadvanced optical techniques.

Diagnostic methodsStandard measurement methods, likeextraction methods, involve the use ofsmoke meters and gravimetric filtration,

I started to work on this project in January2004. My research is focused on the studyof nanoparticles produced by a dieselengine, mainly how their behaviour andformation its affected by injectionparameters and fuel constituyents.

Raúl L. Ochoterena Ph.D. studentThermo and Fluid Dynamics

Sven Andersson Associate

Professor

Project Leader

Mats Andersson Associate

Professor

Raúl L. Ochoterena Ph.D.student


techniques that give a measure of themass emitted in the exhaust of anengine, commonly in g/KWh. However,they do not give information on the sizedistribution of particulate emissions,therefore measurement systems likeLow Pressure Impactors (LPI) andScanning Mobility Particle Sizers (SMPS)are needed.

Optical methods are convenient (butcomplex) diagnostic tools that enableus to obtain information about theconcentration and size distribution ofthe particles instantaneously, in situ,without physical sampling.

The optical systems employed may beset into the combustion chamber orexhaust system, requiring optical accesspoints for the laser light pulses andcameras. A method still underdevelopment is the Laser InducedIncandescence method (LII), withvariants such as Tire LII (Time ResolvedLII) and combinations thereof withother optical approaches, such as Raylix(Rayleigh scattering, LII and Extinction).

Work doneDuring the last autumn I worked in thelaboratory of Professor Bockhorn at theInstitut für Chemische Technik,University of Karlsruhe, Germany,learning about optical experimentaltechniques, like Tire LII and Raylix, asmentioned above. Most of the time wasspent doing Tire LII analyses using astreak camera and a single laser pulsestudying an acetylene flame producedby a flat burner under atmosphericconditions. The rest of the time wasused setting up the Raylix system, andperforming experiments in a lowpressure combustion chamber with aflat burner and an air stream as acounter flow in order to obtain a “tophat” flame. These optical techniques willbe applied in our experiments.

Near-future workDuring this spring another visit toUniversity of Karlsruhe will be made inorder to take Raylix measurements in arapid compression machine to studysoot formation using a new injectionsystem.

Later this spring the Raylix techniquewill be implemented in the ChalmersHigh-Pressure/High Temperature (HP/HT) spray rig, enabling the sizedistribution of soot particles to bedescribed as they are formed at theflame. Several factors that might affectthe soot particle size distribution willbe studied, including the injectionpressure, gas pressure, oxygenconcentration (simulated EGR), theinjection pressure and small injectorholes.

After the spray rig campaign, studieson the exhaust pipe gases in thecombustion chamber of the SingleCylinder Research Engine will beperformed. The aim of this stage willbe to study the coagulation time,composition, shape and sizedistribution of the soot particles in theexhaust gases (as well as the effects ofdifferent variables on the primaryinception of the soot particles). Thegoals of this stage will be to study theeffects on particle coagulation ofvarying the temperature, pressure andresidence time using a dilution tunnelinstalled on the diesel engine. Inaddition, the effects on particlemicrostructure of additives (used toreduce soot emissions) and sulphur inthe fuel will be investigated usingTransmission Electron Microscopy(TEM).

This study will be carried out incollaboration with participants in theCERC project Theoretical andExperimental Investigations ofCombustion of Short Duration SmallDiameter Sprays in Diluted Air, whoare studying the effects of smalldiameter injector holes and multipleinjections on particle size distributionsand amounts. Extraction methods willbe used together with opticalmeasurements. Using both of theseapproaches will help to correlate thedata obtained by them, enhancing ourunderstanding of particle matter and thelimitations and similarities of the twotechniques.


Injection StrategiesIngemar Denbratt, Professor,Project Leader

Malin Alriksson, Ph.DStudent

Direct injection diesel combustion has asignificant advantage in terms of fuelconversion efficiency (with respect to CO

2

emissions) compared to other combustionprinciples. However, today’s diesel enginescannot easily meet the Euro 4/5 emissionsstandards without significantly increasingtheir complexity, since exhaust aftertreatment of NO

x and/or particulates is

required, which reduces their fuel efficiency.Even more stringent standards are expectedto be in force in the USA by 2007 (includinga new driving cycle for heavy duty enginesplus a new system for particlemeasurements taking into accountnanometre-sized particles).Heavy duty truck diesel engines have to befurther improved to meet the targets set bythe Kyoto agreement, as well as theabovementioned, very stringent Euro 4/5emission standards, and the current, alreadyvery low carbon dioxide limits (CO

2=670

g/kWh, corresponding to a fuelconsumption of 210 g/kWh). In order tofulfil future requirements advancedtechnologies concerning fuel injection,combustion systems, air management andafter treatment systems have to bedeveloped.

A possible way to reach Euro 4/5 emissionstandards might be to use the so-calledHCCI combustion approach. Numerousinvestigations have shown its potential toreduce soot and NOx emissions to very lowlevels, but unfortunately such reductionsare often accompanied by increases in fuelconsumption. For heavy duty vehicleswhere higher loads dominate the loadspectra, the obtainable reductions inemissions are limited since it is onlypossible to operate up to about half loadin HCCI mode. This is because the measuresthat currently allow HCCI operation (likesmall included spray angles) have adetrimental effect at high load operation,causing particular problems with airutilisation. Furthermore, other measuresaiming at improving the mixing at light/medium load, like small orifice diameters,are associated with air utilisation problemsat high loads.For heavy duty engines it is thereforeimportant to develop alternative dieselcombustion techniques in order to solvethe so-called diesel dilemma (the NO

x-PM

emissions trade-off).Possible ways of reducing NO

x and PM are

to use high charging pressure, high pressurefuel injection and increased levels of cooledEGR.Multiple injections, especially incombination with EGR, have been shownto reduce particulate and NOx emissions

simultaneously. It has been found thatcareful optimisation of both the strategy(number of injections) and dwell arerequired for different operational conditionsin order to obtain the maximum benefit ofthe combined effects. T. Rente at Chalmersfound that at high load conditions a singleinjection or a split injection with zero dwellis preferable, together with a high NOP, butat lower loads pilot or split injections witha long dwell are better. Under these loadconditions NOP is less important than athigh load. The results suggests that spraywall interactions and mixing due to thelarge-scale vortex formed at the spray tipare very important at high loads, while atlower loads the improved mixing originatingfrom the modification of the flow field fromthe first spray is the dominant effect. Thisalso suggests that varying the nozzle flowrate could help optimise the system. Otherimportant parameters include the swirl andpiston bowl shape, since both the radiusand spray impact angle are importantmixing factors.

It is also well known that the temperaturewindow for soot formation is quite narrowand below 1650 K no soot will be formed,regardless of the equivalence ratio. It ispossible to suppress soot formation, at leastat light load, by using large amounts ofcooled EGR.

The objectives for the project, which startedin December 2004 are:

To study the influence of the injectionstrategy (pilot-main-post or single),injection pressure, NOP, nozzlegeometry (including flow rate) andswirl on fuel consumption andemissions formation for a heavy dutydirect-injection engine.

To identify the most importantparameters for minimising soot andNO

x emissions formation, and

maximising air utilisation for max.BMEP.

The work involves collaboration withparticipants in various other projects beingperformed at Chalmers, especially the SmallOrifice Short Duration Multiple Injectionand Modelling of spray formation CERCprojects and the STEM-financed Spray WallInteractions project.

Malin Alriksson, Ph.D StudentThermo and Fluid Dynamics/VolvoPowertrain AB

Ingemar Denbratt, Professor,Thermo and Fluid Dynamics

I obtained a MSc in Mechanical Engineeringin 2004. I began my work at VolvoPowertrain AB in the same year and myPhD studies as well. My project will focuson reducing emissions from heavy dutydiesel engines


Ingemar Denbratt Professor

Börje Gevert Professor

Atlasi Daneshvar Ph.DStudent

Monica Larsson Ph.D student

Recently, in the fall of 2004, I startedparticipating in this project. The work I willperform is to test different Fischer-Tropschfuels in laboratory engines and evaluatehow different fuel and engine parametersinfluence the emissions. I have an MSc inMechanical Engineering, (specializing inenergy issues) from the Royal Institute ofTechnology, Stockholm.

Monica Larsson, Ph. D studentThermo and Fluid Dynamics

My name is Atlasi Daneshvar Mahvelat.Originally, I came from Iran where I studiedChemical Engineering at Sharif Universityof Technology. In 2002, I was accepted asa master’s student in “EnvironmentallySustainable Process Technology” atChalmers University of Technology. I havejust started my Ph.D., participating in theFischer Tropsch project at the departmentof “Chemical and

Atlasi Daneshvar, Ph. D StudentApplied Surface Chemistry

The European legislation passed tominimize harmful emissions from dieselcombustion systems are becomingstricter, for health and environmentalreasons. The standards are forcingadvances to be made to reduceemissions levels from diverse pollutingdevices, including diesel engines.Current research activity in thecombustion field is intense and aninteresting question being consideredis how the specifications of differentfuels affect exhaust emissions. In thefuture, means of controlling emissionsfrom diesel combustion might includethe development of HCCI systems andthe use of alternative fuels with lowcontents of sulphur, nitrogen andaromatics. Due to the limited reservesof fossil fuel there is also strong interestin producing fuel from renewableenergy sources.

Among all the renewable energysources, biomass has the highestpotential and will play a vital role inthe near future. Sweden has abundantbiomass resources that could beconverted to gas. The wet partialoxidation of biomass produces a gascomposed primarily of hydrogen andcarbon monoxide, also called syngas orbiosyngas. The syngas produced frombiomass contains high percentages ofcarbon monoxide (commonly with ahydrogen to carbon monoxide molarratio of around 1:1). Nevertheless it willbe beneficial to utilise this gas as a rawmaterial in the Fischer TropschSynthesis (FTS) process.

Fischer-Tropsch Fuels for Low Emissions in Diesel Engines

Fischer-Tropsch synthesis (FTS) is aprocess for converting syngas, i.e.hydrogen and carbon monoxide, intoaliphatic hydrocarbons. The productsgenerated by FTS synthesis reactionsare strongly influenced by a number ofvariables, such as the catalyst material,catalyst supports/promoters andreaction conditions (temperature,pressure and the ratio of hydrogen tocarbon monoxide). A number of metalsare suitable as catalysts for FTS, but thethe best catalysts for Fischer andTropsch “gasoline synthesis” processare iron, cobalt and ruthenium.. Ironhas the lowest activity and a relativelyhigh temperature during the synthesisis required. Cobolt is more active andabout six times as expansive.Ruthenium is the most active and mostexpensive catalyst.

The Fischer Tropsch process is currentlyused to produce fuels and chemicalsfrom coal and natural gas. The dieselfuel produced by this process hassuperior quality compared with today’sdiesel fuel produced from petroleum,and its sulfur and aromatic levels arelow.

The research will be performed atChalmers as a collaboration betweenthe Surface Chemistry group and theCombustion group within thedepartment for Applied Mechanics, andpartner companies.

The aim of the combustion group’scontribution to the project is to evaluate

Figure 1. An illustration of the differencebetween conventional diesel fuel andFischer-Tropsch diesel fuel [NationalRenewable Energy Laborator y,http://www.nrel.gov/ve

To the left. Fischer Tropsch Syntetic Disel Fuel. To the right.Conventional Disel Fuel.


how a Fischer-Tropsch diesel fuel affectscombustion and emission formation inan advanced diesel combustion system.The work will mainly consist of engineexperiments on a heavy-duty and alight-duty single cylinder engine withdifferent types of Fischer-Tropsch fuels.Diffusion combustion at mean andheavy loads and the fuel’s compatibilitywith HCCI-combustion are key parts ofthe investigation. Information oninjection parameters, including early orlate injection, will be obtained fromother projects being performed atChalmers. The fuel parameters ofgreatest interest for combustion are thecetane number, the molecular structure,and the vaporization curve. The density,viscosity and surface tension influencethe spray, and hence they also stronglyaffect the combustion.

Börje Gevert is an Associate Professor andheads a research group in fuel preparationfrom both synthetic sources andpetroleum. The main objective of theresearch projects is to develop processesfor the catalytic conversion steps involvedin producing more environmentally friendlyfuels than those in current use.

Börje Gevert Associate ProfessorApplied Surface Chemistry

For the Surface Chemistry group, themain objective of the project is todevelop a means for the active cobaltcatalyst to cope with the low hydrogento carbon ratios that arise from thegasification. Environmental and energyissues related to the Fischer-Tropschmethod will be considered in a life cycleanalysis.

The industries that are involved in theproject are Scania, Volvo Powertrain,Volvo Car Corporation, Fiat-GMPowertrain and Statoil. The companieswill help define the specification of theFischer-Tropsch fuels in order togenerate low emissions and promotecontinuously high performance offuture engines. The companies will alsoperform engine tests with fuels of thespecifications finally chosen.


Management of CERC

Within Chalmers Univers i ty ofTechnology, CERC is an independentunit with i ts own budget andaccounting. CERC’s activities aregoverned by its own board of directorsappointed by the President ofChalmers University of Technology inconsultat ion with the membercompanies.

As the head of CERC Director SivertHi l jemark has had the overal lresponsibility of coordination withinthe centre. During 2004 the boardconsisted of the chairman, threeacademic members and fourrepresentatives from our companiesand one member representing STEM:

Urban Johansson

Chairman of the Board

Scania CV AB.

Tommy Björkqvist

SAAB Automobile Powertrain AB.

Derek Crabb

Volvo Car Corporation

Ingemar Denbratt

Chalmers University of Technology.

Bo Egardt


Bernt Gustafsson

Swedish Energy Agency (STEM).

Jan D Nordvall

ABB Automation Products AB

Arne Rosén


Sören Udd

Volvo Powertrain AB.

Research at CERC is pursued asdescribed in this annual report withproject leaders reporting their resultsdirectly to the CERC board.

During this period, Chalmers University of Technology engaged eleven Ph.D. students, nine ofwhom are at the Department of Thermo and Fluid Dynamics, two is at the Department ofPhysics (Molecular Physics Group) and two are at the Department of Signals and Systems(Signal Processing Group and Control Engineering Group).

The senior research project personnel associated with the activities are equivalent to approxi-mately nine full-time positions. The total workload provided by the participating companiescorresponds to approximately two full-time position.Personnel working at CERC during 2004 were:

Senior Research StaffJerzy Chomiak Prof Thermo and Fluid DynamicsIngemar Denbratt Prof Thermo and Fluid DynamicsArne Rosén Prof Experimental PhysicsMats Viberg Prof Signals and SystemsBo Egardt Prof Signals and SystemsJonas Sjöberg Prof Signals and SystemsSivert Hiljemark Director CERCErik Olsson Prof Emer. CERCValeri Golovitchev Assoc. Prof. Thermo and Fluid DynamicsSven Andersson Assoc. Prof Thermo and Fluid DynnamicsAndrei Lipatnikov Assoc. Prof Thermo and Fluid DynamicsTomas McKelvey Assoc. Prof Signals and SystemsNiklas Nordin Assoc. Prof Thermo and Fluid DynamicsPetter Dahlander Ass oc.Prof Thermo and Fluid DynamicsMats Andersson Ass oc.Prof Experimental PhysicsBörje Gevert Ass oc.Prof Applied Surface Chemistry

Ph.D. studentsAndreas Matsson Ph.D..stud Volvo Power Train ABMalin Alriksson Ph.D..stud Volvo Power Train ABMonica Larsson Ph.D. stud Thermo and Fluid DynamicsAtlasi Daneshvar Ph.D. stud Applied Surface ChemistryRaúl L. Ochoterena Ph.D. stud Thermo and Fluid DynamicsMichael Skogsberg Ph.D. stud Thermo and Fluid DynamicsRichard Ehleskog Ph.D. stud Thermo and Fluid DynamicsRonny Lindgren Ph.D. stud Thermo and Fluid DynamicsFabian Kärrholm Ph.D. stud Experimental PhysicsFredrik Persson Ph.D. stud Experimental PhysicsStina Hemdal Ph.D. stud Experimental PhysicsStefan Larsson Ph.D. stud Signals and SystemsIngemar Andersson Ph.D. stud Signals and Systems

TechnichiansSavo Girja Ph.D Thermo and Fluid DynamicsBo Peterson Ph.D Thermo and Fluid DynamicsLars Jernquist Ph.D Thermo and Fluid DynamicsTorbjörn Sima M.Sc. Thermo and Fluid DynamicsAllan Sognell Eng. Thermo and Fluid DynamicsRolf Berg Eng. Thermo and Fluid DynamicsMorgan Svensson Eng. Thermo and Fluid DynamicsIngemar Johansson Eng Thermo and Fluid Dynamics

A number of representatives from the member industries are also indirectly involved inCERC activities working with the project leader as part of expert groups within eachproject. All persons working on projects have signed special secrecy agreements.

Humanresources


Finances during theperiod 2004-2005

Table 2. Actual contributions from participants 2004 (KSEK)

Revenues Total Cash “In kind”ABB Automation Products AB 1210 760 450 *SAAB Automobile AB 1025 500 525 ***

Scania CV AB 525 400 125Den norske stats oljeselskap s.e. 270 100 170

Volvo Powertrain AB 1625 550 1075 **

AB Volvo Penta 150 100 50Volvo Car Corporation 1275 1000 275 ***

STEM 6000 6000EMFO 520 520

Chalmers Univ. of Technology 7480 750 6730

Transfer from previous year 2218 2218TOTAL 22298 12898 9400BUDGET 22468 12898 9570

Comments on “In kind” contributions:* Development of a new torque sensor.

** Industrial PhD student and equipment.

*** Equipment for DI-project and consultations.

See Table 3 for details.

During 2004-2005, the budget following the agreement between the three parties, STEM/ Industry/CTH given in Table 1 wasestablished.In the summary of the budget below some of the revenues from the participating companies are “efforts in kind”. In thesecond half of 2004, EMFO approved two research projects suggested by CERC, which are now included in the CERCeconomy.Table 2 shows actual input of cash respectively “efforts in kind” for the participating companies during the year 2004.In Table 3, the cost of activities at Chalmers during 2004 are given, distributed by cost categories.Table 4 shows a summary of the project expenses for the year 2004.

Table 1. Total budget for 2004-2005 period (KSEK)

Revenues 2004 2005STEM 6000 6000

EMFO 520 1410

SAAB Automobile Powertrain AB 1025 1060Scania CV AB 525 560

Volvo Power Train AB 1625 1660Volvo Car Corporation 1275 1310

Statoil A.S. 270 370ABB Automation Products AB 1210 1210

AB Volvo Penta 150 150

Chalmers Univ. of Technology 7650 7650Transfer from previous year 2218 2194

TOTAL 22468 23574


Table 3. Expenses at Chalmers 2004 (KSEK)Paid by Chalmers

Personnel expenses Total CERC “in kind”Project director 572 572 0Ph.D Student 4 461 3661 800

Professor 1 669 469 1 200

Research engineer 1 919 1 489 430External consultants 177 177 0

Equipment and DevelopmentComputers 57 57 0Soft ware (Program) 0 0 0

Material 100 100 0

Testing (rig. etc.) 3 090 890 2 200Instruments 660 10 650

Miscellaneous equipment 497 497 0

MiscellaneousTravel 74 74 0Overhead 3 807 2 742 1 065

Premises 460 75 385Unspecified 0 0 0

Salaries 8 798 6 368 2 430

Equipment and Development 4 404 1 554 2 850

Miscellaneous 4 341 2 891 1 450

Total 17 543 10 813 6 730

Table 4. Summary of project expenses 2004 (KSEK)

Chalmers Chalmers Chalmers Chalmers Industry OverallSalaries Equipm. Miscellan. Total Budget Cash Total Budget Total Budget

Project:

Spray-guided gasoline direct

injection (sGDI) 2 001 1 194 1 000 4 195 4 195 3 075 620 620 4 815 4 815

Torque sensors forengine applications 1 100 620 580 2 300 2 300 1 170 630 630 2 930 2 930

Optical two phase diagnostics 790 314 286 1 390 1 390 890 80 80 1 470 1 470

Modeling of spray formation,ignition, and combustion in

internal combustion engines 2 000 340 800 3 140 3 140 1 810 130 130 3 270 3 270

Combustion of short duration

small diameter spray 800 524 451 1 775 1 775 1 375 20 20 1 795 1 795

Nanoparticles 900 250 350 1 500 1 500 1 100 20 20 1 520 1 520

Future diesel combustion 210 25 25 260 733 110 950 950 1 210 1 683

Fischer-Tropsch fuels for low

emissions in diesel engines: Engine tests 120 82 50 252 252 252 120 120 372 372

Process developments 50 0 10 60 250 60 100 100 160 350

Administration * 827 1 055 789 2 671 2 800 971 0 0 2 671 2 800

TOTAL 8 798 4 404 4 341 17 543 18 335 11 505 2 670 2 670 20 213 21 005

* including “In kind” CTH equipment


1. Lipatnikov, A.N. and Chomiak, J.“Developing Premixed TurbulentFlames: Part I. A Self-Similar Regimeof Flame Propagation”, CombustionScience and Technology, 162, pp. 85-112, 2001.

2. Lipatnikov, A.N. and Chomiak, J.“Developing Premixed TurbulentFlames: Part II. Pressure-DrivenTransport and Turbulent Diffusion”,Combustion Science and Technology,165, pp. 175-195, 2001.

3. Lipatnikov, A.N. and Chomiak, J.“Modeling of Pressure and Non-Stationary Effects in Spark IgnitionEngine Combustion: A Comparison ofDifferent Approaches”, SAETransactions, Vol. 109, Section 3,Journal of Engines, 2001 (SAE Paper2000-01-2034).

4. Lipatnikov, A.N. and Chomiak, J.“Turbulent Flame Speed and Thicknessas Tools for Multi-DimensionalComputations of Premixed TurbulentCombustion”, Progress in Energy andCombustion Science, 28, pp. 1-73,2002.

5. Lipatnikov, A.N. and Chomiak, J.“Highly Turbulent Combustion andFlame Quenching”, First BiennialMeeting and General Section Meetingof the Scandinavia-Nordic Section ofthe Combustion Institute, Gothenburg,April 18-20, 2001, pp.7-12.

6. Lipatnikov, A.N. and Chomiak, J. “AreSteady Premixed Turbulent FlamesFully Developed?”, Proceedings of theThird Pacific Conference onCombustion ASPACC 2001, Seoul, June24-27, 2001, pp.83-86.

7. Lipatnikov, A.N. and Chomiak, J.“Towards Evaluation of TurbulentFlame Speed”, The Fifth InternationalSymposium on Diagnostics andModeling of Combustion in InternalCombustion Engines, Nagoya, July 1-4,2001. CD.

8. Lipatnikov, A.N. and Chomiak, J.“Simulations of Premixed TurbulentStagnation Flames with a FlameSpeed Closure Model”,18thInternational Colloquium on theDynamics of Explosion and ReactiveSystems, July 29 - August, 3, 2001,Seattle, Washington. CD. ISBN# 0-9711740-0-08.

9. Lipatnikov, A.N. and Chomiak, J. “AMethod for Evaluating Fully DevelopedTurbulent Flame Speed”, InternalCombustion Engines, Proceedings ofthe 5-th International Conference ICE2001, September 23-27, 2001, Capri-Naples. CD CNR - Istituto Motori. PaperSI2 - 2001-01-046.

10. Lipatnikov, A.N. and Chomiak, J.“Testing of Premixed TurbulentCombustion Models for Gas Turbineand Engine Applications”, Combustionand the Environment, XXIV Event of theItalian Section of the CombustionInstitute, September 16-19, 2001, S.Margherita Ligure. pp. VIII.7-VIII.10.

11. Lipatnikov, A.N. and Chomiak, J. “ArePremixed Turbulent Stagnation FlamesEquivalent to Fully Developed Ones?”Proceedings of the SecondMediterranean CombustionSymposium, 6-11 January, 2002,Sharm El-Sheikh, Egypt, Eds. by M.S.Mansour and M. Kamel, Vol. 1, pp.169-171, 2002.

12. Lipatnikov, A.N. and Chomiak, J.“Towards Evaluation of TurbulentFlame Speed”, The Fifth InternationalSymposium on Diagnostics andModeling of Combustion in InternalCombustion Engines, COMODIA2001,Nagoya, July 1-4, 2001, p.31.

13. Lipatnikov, A.N. and Chomiak, J. “AMethod for Evaluating Fully DevelopedTurbulent Flame Speed”, InternalCombustion Engines, Abstracts of the 5-th International Conference ICE 2001,September 23-27, 2001, Capri-Naples.CNR - Istituto Motori, p.89, 2001.

14. Michael Försth, “Laser Diagnostics andChemical Modeling of Combustion andCatalytic Processes”. Ph.D.Thesis,Dep.of Experimental Physics, ChalmersUniversity of Technology, 2001.

15. Rafeef Abu-Gharbieh, “Laser SheetImaging and Image Analysis forCombustion Research”. Ph.D.Thesis,Dep. of Experimental Physics,Chalmers University of Technology,2001.

16. Golovitchev, V.I., Nordin, N., “DetailedChemistry Spray Combustion Model forthe KIVA Code”, The 11th InternationalMultidimensional Engine ModelingUser’s Group Meeting at the SAECongress, Detroit, March 4, pp. 1-6(2001).

17. Golovitchev, V.I., Nordin, N., andChomiak, J., ”On Length of Flame Lift-off and Combustion Zone Structure ofDI Diesel Sprays”, First BiennialMeeting of the Scandinavian-NordicSection of the Combustion Institute,Goteborg, April 18-20, pp. 145-150(2001)

18. Rente, T., Golovitchev, V.I., andDenbratt, I., “Numerical Study of PilotInjection and Ignition of n-HeptaneDiesel Spray”, First Biennial Meeting ofthe Scandinavian-Nordic Section of theCombustion Institute, G¨ oteborg, April18-20, pp. 13-18 (2001)

19. Rente, T., Golovitchev, V.I., andDenbratt, I., “Numerical Study of n-Heptain Diesel Spray Auto-ignition atDifferent Level of Pre-ignitionTurbulence”, The 5th InternationalSymposium on Diagnostics andModeling in Internal CombustionEngines, COMODIA2001, Nagoya, July1-4 (2001)

20. Tao, F., Golovitchev, V.I., and Chomiak,J., “Application of Complex Chemistryto Investigate the Combustion ZoneStructure of DI Diesel Sprays underEngine-like Conditions”, The 5thInternational Symposium onDiagnostics and Modeling in InternalCombustion Engines, COMODIA2001,Nagoya, July 1-4 (2001).

21. Rente, T., Golovitchev, V.I., and

Denbratt, I., “Effect of InjectionParameters on Auto-ignition and SootFormation in Diesel Sprays”, SAEPaper 2001-01-3687 (2001).

22. Golovitchev, V.I., “Revising ”Old” GoodModels: Detailed Chemistry SprayCombustion Modeling Based on EddyDissipation Concept”. The 5thInternational Conference InternalCombustion Engines, ICE2001, Capri-Naples, September 23-27 (2001).

23. Golovitchev, V.I., and Chomiak, J.,“Structure of Combustion Zone andSoot Formation in Lifted DI DieselSpray Flames”, The 24th Event of theItalian Section of the CombustionInstitute Combustion and Environment,S.Marghareta Ligure, September 16-19, pp. IV-7/IV-10 (2001).

24. Golovitchev, V.I., and Chomiak, J.,”Numerical Modeling of HighTemperature Air ”Flameless”Combustion”, The 4th InternationalSymposium on High Temperature AirCombustion and Gasification, Rome,November 26-30 (2001).

25. Stefan Larsson, “Literature Study onExtremum Control”. Teknisk rapport,R007/2001. Control and AutomationLaboratory, Department of Signals andSystems, Chalmers University ofTechnology, Göteborg, Sweden, 2001.

26. Stefan Larsson, “Torque Optimizationin Combustion Engines / A FeasibilityStudy”. Teknisk rapport, R009/2001Control and Automation Laboratory,Department of Signals and Systems,Chalmers University of Technology,Göteborg, Sweden, 2001.

27. Andreas Matsson, “Diesel particulatematter emissions: Background,characterization and reductionproblems”. Lic Thesis 2000. Thermoand fluid dep. Chalmers University ofGothenburg.

28. Andreas Matsson, “The effect of nozzleinlet conditions on fuel consumptionand emissions of a heavy duty dieselengine”. JSAE 20015345.

29. Lionel Christopher Ganippa, AndreasMatsson, Sven Andersson, and JerzyChomiak: “Combustion Characteristicsof Diesel Sprays from Nozzles withSharp and Rounded Inlet Geometries”submitted for combustion symposium2002.

30. Lipatnikov, A.N. and Chomiak, J.“Turbulent Flame Speed and Thicknessas Tools for Multi-DimensionalComputations of Premixed TurbulentCombustion”, submitted to Progress inEnergy and Combustion Science,2000.

31. Lipatnikov, A.N. and Chomiak, J.“Testing Different Models of PremixedTurbulent Flame Development”.Unsteady Combustion and InteriorBallistics. Lectures of the IIIInternational Workshop, June 26-30,2000, Saint Petersburg, Russia, Vol. I,pp.70-80, 2000.

32. Lipatnikov, A.N. and Chomiak, J.“Transition from Gradient to Counter-Gradient Transport in Developing

References


Premixed Turbulent Flames,” OpenMeeting on Combustion. XXIII Event ofthe Italian Section of the CombustionInstitute. Lacco Ameno, Ischia, May 22-25, 2000. CD.

33. Lipatnikov, A.N. and Chomiak, J.“Counter-Gradient Diffusion inPremixed Turbulent Flames: an OldProblem Revisited,” Chemical Physicsof Combustion and ExplosionProcesses. XII Symposium onCombustion and Explosion.Proceedings. IPKhPh RAN,Chernogolovka, Moscow region, Russia.Vol. 1, pp. 185-186, 2000.

34. Lipatnikov, A.N. and Chomiak, J.“Transition from Gradient to Counter-Gradient Transport in DevelopingPremixed Turbulent Flames”, 28th

International Symposium onCombustion. Abstracts of Work-in-Progress Poster Presentations. TheCombustion Institute, Pittsburgh,p.167, 2000.

35. Lipatnikov, A.N. and Chomiak, J.“Testing Different Models of PremixedTurbulent Flame Development,”Unsteady Combustion and InteriorBallistics. International Workshop,June 26-30, 2000, Saint Petersburg,Russia. Proceedings. pp.36-37.

36. Wallesten, J. and Chomiak, J.“Investigation of Spark Position Effectsin a Small Pre-Chamber on Ignitionand Early Flame Propagation”, SAEPaper 2000-01-2839, 2000.

37. Sandquist, H., Denbratt, I., Owrang, F.,and Olsson, J., “Influence of fuelParameters on Deposit Formation andEmissions in a Direct InjectionStratified Charge SI Engine”, SAESpecial Publications, vol. 1629, pp.207 - 218, SAE Paper 2001-01-2028,2001.

38. Sandquist, H., Karlsson, M., andDenbratt, I., “Influence of EthanolContent in Gasoline on SpeciatedEmissions from a Direct InjectionStratified Charge SI Engine”, SAESpecial Publications, vol. 1584, pp. 221- 229, SAE Paper 2001-01-1206, 2001.

39. Sandquist, H. and Denbratt, I., “Cycle-Resolved NO Measurements in theExhaust Port of a Direct InjectionStratified Charge SI Engine”, Paper in“Direkteinspritzung im Ottomotor III”,expert verlag, Renningen, Germany, pp.345 - 361, 2001.

40. Sandquist, H. “Influence of FuelParameters on Deposit Formation andEmissions in Direct Injection StratifiedCharge SI Engine”. Ph. D. Thesis, Dep.of Thermo- and Fluid Dynamics,Chalmers University of Technology.

41. Sandquist, H., Karlsson, M., andDenbratt, I., “Influence of EthanolContent in Gasoline on SpeciatedEmissions from a Direct InjectionStratified Charge”, to be presented at2001 SAE World Congress, March 5-8,Detroit, Michigan, USA, 2001.

42. Lionel C. Ganippa, G. Bark, S.

Andersson, J. Chomiak, ”Structure ofCavitation and its Effect on SprayPattern in a Single Hole Diesel Nozzle”,SAE International Spring Fuels &Lubricants Meeting, Orlando (FL), May2001.

43. Lionel C. Ganippa, G. Bark, S.Andersson, J. Chomiak, ” Comparisonof Cavitation Phenomena inTransparent Upscale Diesel Nozzles”,CAV2001, The Fourth InternationalSymposium on Cavitation, Pasadena(CA), June 2001.

44. Lundström, D, and Schagerberg, S.,“Misfire Detection for Prechamber SIEngines Using Ion Sensing andRotational Speed Measurements”, SAESpecial Publications, vol. 1586, pp. 79- 84, SAE Paper 2001-01-0993, 2001.

45. Abu-Gharbieh, R., Persson, J., Försth M.,Rosén A., Karlström A., Gustavsson T.,“Compensation method for attenuatedplanar laser images of optically densesprays”, Applied Optics 39, 1260(2000).

46. Michael Försth, “Laser Diagnostics ofDense Sprays”, Nordic Symposium onCombustion, Lund April 27, 2000.

47. Arne Rosén, Michael Försth, and JohnPersson, Rafeef Abu-Gharbieh andTomas Gustavsson “Laser Diagnosticsof Dense Sprays”, EdinburghConference, 2000.

48. Michael Försth, “Turbulence andFractal Analysis using Wavelets”,Project work.

49. Michael Försth and Hui Lui, “WaveletMultiresolution Analysis of SprayImages from a Diesel Injector”, 3rdPacific Symposium on FlowVisualization and Image Processing,March 2001.

50. Pär Bergstrand and Michael Försth andIngemar Denbratt “Investigation ofDiesel spray injection into highpressure conditions with reducednozzle orifice diameter”, 2001 JSAESpring Convention in Yokohama, Japan,May 2001.

51. G. Hanehöj, “Laser measurements on adirect injection two stroke Husqvarnaengine”.

52. Golovitchev, V.I., and Chomiak, J.,Comprehensive Chemical Mechanismof Soot Formation for Diesel SprayCombustion Modeling, XXII Event of theItalian Section of the CombustionInstitute, Lacco Ameno, Ischia, May 22-25 (2000).

53. Golovitchev, V.I., Nordin, N., Jarnicki, R.,and Chomiak, J., 3-D Diesel SpraySimulations Using a New DetailedChemistry Turbulent CombustionModel, SAE Paper 200-01-1891(2000).

54. Tao, F., Some Physical and ChemicalAspects of Soot Formation andOxidationin Spray CombustionModeling, Thesis for the degree ofLicentiate of Engineering, ChalmersUniversity of Technology (2000).

55. Tao, F., Golovitchev, V.I., and Chomiak,

J., Self-Ignition and Early CombustionProcess of n-Heptane Sprays UnderDiluted Air Conditions: NumericalStudiesBased on Detailed Che-mistry,SAE Paper 2000-01-2931 (2000).

56. Nordin, N., Complex ChemistryModeling of Diesel Spray Combustion,Thesis for the degree of Doctor ofEngineering, Chalmers University ofTechnology (2000).

57. Jarnicki, A. Teodorczyk, V. Golovitchev,and J. Chomiak, Numerical Simulationof Spray Formation, ignition andCombustion in a Diesel Engine, UsingComplex Chemistry Approach, The26th International Conference onInternal Combustion Engines ”KONES2000”, September 10-13, 2000,Naleczow, Poland.

58. Golovitchev, V.I., and Chomiak, J.,Simple Detailed Chemistry Approachfor Turbulent Spray CombustionModeling, 28th (International)Symposium on Combustion, TheCombustion Institute, Pittsburgh,Abstracts 5-B14 of W-in-P session, p.450 (2000).

59. Golovitchev, V.I., Revising ”Old” GoodModels: Magnussen Turbulent EddyDissipation Concept FormalSubstantiation, Interpretation andApplication to Detailed ChemistrySpray Combustion in ICE. TopicalMeeting ”On Modeling of Combustionand Combustion Processes”, Abo/Turky, Finland, 15- 16 November,(2000).

60. Lipatnikov, A.N. and Chomiak, J. “ASelf-Similar Regime of PremixedTurbulent Flame Development,”submitted to the 28th Symposium(International) on Combustion.

61. Lipatnikov, A.N. and Chomiak, J.“Dependence of Heat Release onProgress Variable in PremixedTurbulent Combustion,” Proceedings ofthe Combustion Institute, 28, in press.

62. Lipatnikov, A.N. and Chomiak, J.“Modeling of Pressure and Non-Stationary Effects in Spark IgnitionEngine Combustion: A Comparison ofDifferent Approaches”, SAE Paper2000-01-2034.

63. Lipatnikov, A.N. and Chomiak, J.“Transient and Geometrical Effects inExpanding Turbulent Flames”,Combustion Science and Technology,in press.

64. Lipatnikov, A.N. and Chomiak, J. “ANumerical Study of the TurbulentFlame Speed Development AfterIgnition,” Joint Meeting of the British,German and French Sections of theCombustion Institute. Abstracts. 18-21 May 1999, Nancy, France, pp. 65-67, 1999.

65. Lipatnikov, A.N. and Chomiak, J.“Burning Velocity at StrongTurbulence: Role of Flame Geometryand Transient Effects”, Proceedings ofthe Mediterranean CombustionSymposium - 99, Eds. by F. Beretta.pp. 1038-1049, 1999.


66. Lipatnikov, A.N. and Chomiak, J. “ANumerical Study of Turbulent FlameSpeed Development in the SphericalCase,” 17th International Colloquiumon the Dynamics of Explosion andReactive Systems, July 25-30, 1999,Heidelberg, Germany. CD ISBN 3-932217-01-2. Paper 026.

67. Chomiak, J. and Lipatnikov, A.N. “OnMechanisms Contributing to theBending of Turbulent Burning VelocityCurve,” Joint Meeting of the British,German and French Sections of theCombustion Institute. Abstracts. 18-21May 1999, Nancy, France, pp. 9-11,1999.

68. Lipatnikov, A.N. and Chomiak, J.“Effects of Turbulence Length Scale onFlame Speed: a Modelling Study,”Engineering Turbulence Modelling andMeasurements 4, Eds. by W. Rodi andD. Laurence, Elsevier, Amsterdam,pp.841-850, 1999.

69. Wallesten, J. “Modeling of FlamePropagation in Spark Ignited Engines”.Licentiate thesis. 1999.

70. Sandquist, H. and Denbratt, I.“Comparison of Homogeneous andStratified Charge Operation in a DirectInjection Spark Ignition Engine”,presented at The 15th InternalCombustion Engine Symposium, Seoul,Korea, 13-16 July, 1999.

71. Sandquist, H. and Denbratt, I.“Influence of Fuel Volatility on Cycle-Resolved Hydrocarbon Emissions froma Direct Injection Spark IgnitionEngine”, presented at the GasolineDirect Injection Engine Congress,Munich, Germany, 16-17 November,1999. CERC – Annual Report 2000 22.

72. Sandquist, H. and Denbratt, I.,“Sources of Hydrocarbon Emissionsfrom a Direct Injection StratifiedCharge Spark Ignition Engine”, SAESpecial Publications, vol. 1547, pp.101 - 111, SAE Paper 2000-01-1906,2000.

73. Andreas Matsson, Lisa Jacobsson,Sven Andersson, ”The Effect ofElliptical Nozzle Holes on Combustionand Emission Formation in a HeavyDuty Diesel Engine ”, SAE 2000,Detroit, Paper 2000-01-1251.

74. Moh’d Abu-Qudais, Andreas Matsson,David Kittelson, ”Combination ofMethods for Characterisation DieselEngine Exhaust Particulate Emissions”,accepted for publication in JSMEjournal.

75. R. Abu-Gharbieh, J. L. Persson, M.Försth, A. Rosén, A. Karlström, T.Gustavsson, “A Compensation Methodfor Attenuated Planar Laser Images ofOptically Dense Sprays, ”Applied Optics(2000), in press.

76. M. Försth, “Laser Diagnostics andModeling of the Coupling betweenHeterogeneous Catalytic and Gas-Phase Oxidation of Hydrogen”, Licentiatethesis (1998).

77. Abu-Gharbieh R. “Laser Sheet Imaging

and Image Analysis Applied to SprayDiagnostics”, Lic. Thesis, TechnicalReport No. 317L, Chalmers Universityof Technology, (1999).

78. M. Försth, P. C. Hinze, P. Miles, ”Onedimensional temperaturemeasurements in an IC engine usingspontaneous Raman scattering”,Article in preparation.

79. Golovitchev, V.I., Nordin, N., Chomiak,J., and Nishida, K., Evaluation ofignition quality of neat DME at Diesel-like conditions. Paper published in theProceedings of the InternationalConference ICE99: InternalCombustion Engines: Experiments andModeling, Capri- Naples, September12-16 (1999).

80. Tao, F., Golovitchev, V.I., and Chomiak,J., Numerical Modeling of Auto-Ignition,Combustion, and Soot Formation in n-Heptane Sprays in a High PressureConstant-Volume Chamber. Paperpublished in the Proceedings of theInternational Conference ICE99:Internal Combustion Engines:Experiments and Modeling, Capri-Naples, September 12-16 (1999).

81. Golovitchev, V.I., Tao, F., and Chomiak,J., Numerical Evaluation of SootFormation Control at Diesel-LikeConditions by Reducing Fuel InjectionTiming, SAE Paper 99FL-388 (1999).

82. Golovitchev, V.I., Nordin, N., DetailedChemistry Sub-Grid Scale Model ofTurbulent Spray Combustion for theKIVA code, Paper published in theProceedings of the ASME 1999 FallTechnical Conference. Session ”In-cylinder Flow CombustionMeasurements and Model-ing”,October 16-20, Ann Arbor, Michigan,USA (1999).

83. Golovitchev, V.I., Nordin, N., KIVA 3-DSimulations Using a New DetailedChemistry Diesel Spray CombustionModel, Paper published in theProceedings of the Workshop”Combustion Modeling in I.C.E.”,December 14-15, Cassino, Italy(1999).

84. B. van Norel, R. I. le Grand, ”How tomeasure the air entrainment in dieselsprays”, Internal report 99/10,Department of Thermo and FluidDynamics, Chalmers University ofTechnology, 1999.

85. Lionel C. Ganippa, S. Andersson, J.Chomiak, ”Transient Measurements ofDischarge Coefficients of DieselNozzles”, SAE paper 2000-01-2788.

86. S. Gjirja, “Engine Design Optimization,a Practical Technology for OptimumPerformance and Emissions of anEthanol Fueled Engine”, Paper No97EL008, International ConferenceProceedings, 30th ISATA, Florence,Italy,1997.

87. S. Gjirja, E. Olsson, “Ether as IgnitionImprover and Its Application onEthanol Fueled Engine”, Internskrift Nr

97/15, Thermo & Fluid Dynamics,Chalmers University of Technology,1997. Also published as KFB-Meddelande 1997:38.

88. S. Gjirja, E. Olsson, A. Karlström, “EtherFumigation, a New Alternative for theNeat Ethanol Diesel Engine” , Paper No98EL008, International ConferenceProceedings, 31st ISATA, Clean PowerSources & Fuels. Special InnovativeConference: Intelligent TransportationSystems, Düsseldorf, Germany, 1998.

89. S. Gjirja, E. Olsson, A. Karlström,“Investigations on Methanol Enginewith DME Fumigation”, Paper99CPE007, 32 nd ISATA, June 14-17,Vienna, Austria, 1999.

90. H. Armbruster, J. Van Gunsteren, S.Stucki, E. Olsson, S. Gjirja, “On-boardconversion of alcohols to ethers forfumigation in diesel engine s”, Paperat International Symposium on AlcoholFuels, ISAF XIII, in Stockholm 3-6 July2000.

91. Lipatnikov, A.N., J. Wallesten, J.Chomiak, and J. Nisbet, “Computationsof Combustion in Bombs and an SI-Engine Using a Turbulent Flame SpeedClosure Model and Modified FIRECode”. Computational Technologies forFluid/Thermal/Chemical Systems withIndustrial Applications, Vol. II, ASME,New York, pp. 199-206, 1998.

92. Lipatnikov, A.N., Wallesten, J., andNisbet J., “Testing of a Model for Multi-Dimensional Computations ofTurbulent Combustion in Spark IgnitionEngines”, COMODIA 98 - The FourthInternational Symposium onDiagnostics and Modeling ofCombustion in Internal CombustionEngines}, JSME, Kyoto, pp. 239-244,1998.

93. Wallesten, J., Lipatnikov, A.N., andNisbet J., “Turbulent Flame SpeedClosure Model: Further Developmentand Implementation for 3-D Simulationof Combustion in SI Engine”, SAEPaper 982613, 1998.

94. Wallesten, J., Lipatnikov, A.N., Chomiak,J., and Nisbet J., “3D Simulation ofCombustion in SI Engine Using aTurbulent Flame Speed ClosureModel”. Expose överförbränningsforskningen i Sverige,Chalmers Institute of Technology,Gothenburg, 21-22 October 1998,p.62.

95. Lipatnikov, A.N. and Chomiak, J.,“Effects of Turbulence Length Scale onFlame Speed: A Modelling Study”,submitted to 4th InternationalSymposium on Engineering TurbulenceModelling And Measurements, Corsica,France, May 24-26, 1999.

96. Lipatnikov, A.N. and Chomiak, J.,“Randomness of Flame KernelDevelopment in Turbulent GasMixture”, SAE Paper, 1998.

97. Lipatnikov, A.N. and Chomiak, J., “LewisNumber Effects in Premixed TurbulentCombustion and Highly PerturbedLaminar Flames”, Combustion Science


and Technology, 1998, in press.

98. Lipatnikov, A.N. and Chomiak, J.,“Burning Velocity at StrongTurbulence: Role of Flame Geometryand Transient Effects”, submitted toMediterranean CombustionSymposium, Antalya, Turkey, June 20-25, 1999.

99. Håkan Sandqvist, Ingemar Denbratt,Åsa Ingemarsson, Jim Olsson,“Influence of Fuel Volatility onEmissions and combustion in a directinjection Spark Ignition Engine”. SAE-paper 982701. SAE Fall meeting SanFransisco. 1998.

100.Åsa Ingemarsson, “Emissions fromcombustion and pyrolysis from liquidand solid fuels investigated using GC/MS and GC/FTIR/FID”. Licentiatethesis 1998. Institutionen förfysikalisk kemi, Chalmers tekniskaHögskola.

101.Åsa Ingemarsson, Jörgen Pedersen,Jim Olsson, “Sampling from n-Heptane/air flames with on-line GC/FID and GC/MS. Two differentsampling strategies”. Internal report1997-03-24.

102.Åsa Ingemarsson, Jörgen Pedersen,Jim Olsson, “Emissions analysis GC/MS on an Ethanol/Ether Fuelledengine”. Internal report 1997-06-23.

103.Åsa Ingemarsson, Jörgen Pedersen,Jim Olsson, “Summary of GC/MSmeasurements on a Methanol/DMEengine”. Internal Report 1998-06-17.

104.Åsa Ingemarsson, Jörgen Pedersen,Jim Olsson, “Identification of keycompounds in gasoline and oxygenateflame combustion”. Internal report1997-04-08.

105.Åsa Ingemarsson, Jörgen Pederssen,Jim Olsson, “Emisionsanalys avoxygenatbränslen. Speciellt etanol/dietyleter blandningar. Metod försnabb analys med mikro GC”. Internalreport 1996 10-25.

106.Åsa Ingemarsson, Jörgen Pederssen,Jim Olsson, “Emissionsanalys avoxygenatbränslen. Speciellt etanol/diethyleter blandningar. Metod för GC/MS analys med GCD”. Internal report1997-03-24.

107.Jörgen Pedersen, Åsa Ingemarsson,Jim Olsson, “Oxidation of RapeseedOil, Rapeseed Methyl Ester (RME) andDiesel Studied With GC/MS”.Chemosphere 1998.

108.Pär Bergstrand och Mattias Marklund,“Design and construction of a sprayrig for investigation of cavitation indiesel injectors”, MSc thesis,Department of Thermo and FluidDynamics, Chalmers University ofTechnology, 1998.

109.Matsson, A., “Different Methods ForCharacterization of Diesel EngineExhaust Particulate Emissions”,Presented at the CERC seminar,Chalmers, Göteborg, 1999-03-03.

110.Golovitchev, V.I., Nordin, N., and

Chomiak, J., “Neat Dimethyl Ether: Is itReally Diesel Fuel of Promise?”. SAEPaper 982537 (1998).

111.Golovitchev, V., and Chomiak, J.,“Evaluation of Ignition Improvers forMethane Autoignition”. Journ.Combust. Sci. and Tech., vol. 135, pp.31-47 (1998).

112.Nordin, N., Golovitchev, V.I., andChomiak, J., “Computer Evaluation ofDI Diesel Engine Fueled with NeatDimethyl Ether”. Proceedings of the22nd CIMAC, 18-21 May, Copenhagen,vol.2, pp. 408-421 (1998).

113.Nordin, N., “Numerical Simulations ofNon-Steady Spray Combustion Usingthe Detailed Chemistry Approach”.Thesis for the degree of Licentiate ofEngineering, Chalmers University ofTechnology (1998).

114.Gjirja, S., Olsson, E., Karlström, A.,Ingemarsson, Å., Berg, R., ”AlcoholEngines with Ether as IgnitionImprovers. Literature Review andSuggestions”. Internskrift Nr 96/27,Thermo & Fluid Dynamics, ChalmersUniversity of Technology, 1996.

115.Gjirja, S., Olsson, E.,”Ether as IgnitionImprover and Its Application onEthanol Fueled Engine”, Internskrift Nr97/15, Thermo & Fluid Dynamics,Chalmers University of Technology,1997. Also published as KFB-Meddelande 1997:38.

116.Golovitchev, V., Nordin, N., Chomiak, J.,”Modeling of Spray Formation, Ignitionand Combustion in InternalCombustion Engines”. Publication Nr98/1, Thermo & Fluid Dynamics,Chalmers University of Technology,1998.

117.Gjirja, S., Olsson, E., ”On-BoardManufactured Ethers as an IgnitionImprover for Alcohol Engines.Reference Test with Poly-Ethylene-Glycol (PEG) Ignition Improver”.Internskrift Nr 98/9, Thermo & FluidDynamics, Chalmers University ofTechnology, 1998.

118.Gjirja, S., Olsson, E., ”OnboardManufactured Ethers as an IgnitionImprover for Alcohol Engines. Effectsof the DME Fumigation on MethanolEngine Performance and EmissionLevels”. Internskrift Nr 98/10, Thermo& Fluid Dynamics, Chalmers Universityof Technology, 1998.Systems,Düsseldorf, Germany, 1998.

119.Gjirja, S., Olsson, E., Karlström, A.,”Considerations on Engine Design andFuelling Technique Effects onQualitative Combustion in AlcoholDiesel Engines”. SAE International FallFuels and Lubricants Meeting, Paper98FL-322, San Fransisco, USA,October 19-22, 1998.

120.CERC – Combustion Engine ResearchCenter ”Annual Report 1996”.Chalmers University of Technology,http://www.tfd.chalmers.se/CERC/(1996).



123.Lipatnikov, A.N. and Chomiak, J., “ASimple Model of Unsteady TurbulentFlame Propagation”, SAE Paper972993 (1997).

124.Lipatnikov, A.N. and Chomiak, J.,”Modeling of Turbulent FlameDevelopment in Spark IgnitionEngines”, Proceedings of 3rd

International Conference on InternalCombustion Engines: Experiments andModeling, Instituto Motori, Naples,pp.75-82 (1997).

125.Lipatnikov, A.N. and Chomiak, J.,”Simulations of the Effect of StrongPerturbations on Laminar Flames”,16th International Colloquium on theDynamics of Explosions and ReactiveSystems. August 3-8, 1997.Conference Proceedings, University ofMining and Metallurgy, Cracow, pp.406-409 (1997).

126.Lipatnikov, A.N. and Chomiak, J.,”Modeling of Turbulent FlamePropagation”, Chalmers University ofTechnology, Göteborg (1997). 1217.Lipatnikov, A.N. and Chomiak, J. ”LewisNumber Effects in Premixed TurbulentCombustion and Highly PerturbedLaminar Flames”, submitted toCombust. Sci. and Tech. (1997).

128.Lipatnikov, A.N. and Chomiak, J.,”Minimum Ignition Energy andRandomness of Flame Development inTurbulent Gas”, XVth InternationalSymposium on Combustion Processes,Zakopane, September, 8-12, 1997.Abstracts Polish Academy of Sciences,p. 20 (1997).

129.Burgdorf, K. and Karlström, A., ”UsingMulti-Rate Filter Banks to DetectInternal Combustion Engine Knock”.SAE Paper 971670 (1997).

130.Karlström, A., Lundström, D. andViberg, M., ”Knock Localization inInternal Combustion Engines UsingMultiple Pressure Sensors”. ChalmersUniversity of Technology, Techn. Report-CTH-TE-66 (1997).

131.Lundström, D., Karlström, A., “TransientIdentification using a FractionalDerivative Model”. Accepted forpublication at the European ControlConference ECC99, August 31 –September 3, Karlsruhe (1999).

132.Andersson, S., Wallesten, J., ”Ethanoland Ether (DEE) Spray Experiments –PDA Measurements and VideoImaging”, Report No 97/23, Dept. ofThermo and Fluid Dynamics, ChalmersUniversity of Technology (1997).

133.Persson, J., Försth, M., Rosén, A.,


”Spray diagnostics 970401”, ReportNo 98/1, Dept. of Physics (theMolecular Physics Group), ChalmersUniversity of Technology (1997).

134.Golovitchev, V. and Nordin, N., ”FIREcode, v6.2b: Droplet EvaporationModels”. Chalmers University ofTechnology, Dept. of Thermo and FluidDynamics, Technical Report 97/22(1997).

135.Nordin, N. and Golovitchev, V.,”Numerical Evaluation of n-HeptaneSpray Combustion at Diesel LikeConditions”. The 7th Internat. KIVAUsers Meeting at the SAE Congress,February 23, 1997, Detroit, Book ofAbstracts, pp.1-5 (1997).

136.Golovitchev, V. and Nordin, N.,”Numerical Evaluation of DualOxygenated Fuel Setup for DI DieselApplication”. SAE Paper 971596(1997).

137.Golovitchev, V., Nordin, N. andChomiak, J., ”Modeling of SprayFormation, Ignition and Combustion inInternal Combustion Engines”. AnnualReport (1997).

138.Golovitchev, V., “Micro-Mixing TimeDefinition in the Eddy DissipationConcept”, Combustion Science andTechnology, accepted for publicationin 2002.

139.Lipatnikov, A.N. and Chomiak, J.“Turbulent Flame Speed andThickness:Phenomenology, Evaluation,and Application in Multi-DimensionalSimulations”, Progress in Energy andCombustion Science, 28, No. 1, pp. 1-73, 2002.

140.Lipatnikov, A.N. and Chomiak, J.“Turbulent Burning Velocity and Speedof Developing, Curved, and StrainedFlames”, Proceedings of theCombustion Institute, 29, in press.

141.Wallesten, J., Lipatnikov, A.N., andChomiak, J.“Modeling of stratifiedcombustion in a DI SI engine usingdetailed chemistry pre-processing”,Proceedings of theCombustion Institute, 29, in press.

142. Golovitchev, V. and Chomiak, J.“Numerical Modeling of High-Temperature Air FlamelessCombustion”, Proceeding of the 6thEuropean Conference INFUB, Lisbon,Portugal, Eds. by Reis, Ward andLeuckel, Vol. 1, pp. 325-340, 2002.

143.Golovitchev, V., “Towards UniversalModel of Turbulent Combustion”, NinthInternational Conference onNumerical Combustion, April 7-10,2002, Sorrento, Italy. pp. 324-325.

144.Golovitchev, V. and Chomiak, J.“Analysis of Main AssumptionsUnderlying the Revised EDC Approachfor Combustion Modeling”, Proceedingof Scandinavian-Nordic Section of theCombustion Institute, September 10-11, 2002, Trondheim, Norway.

145.Tao, F.,and Chomiak, J. “NumericalInvestigation of Reaction ZoneStructure and Flame Lift-Off of DIDiesel Sprays with ComplexChemistry”, SAE Paper 2002-01-1114.

146.Lipatnikov, A.N., Chomiak, J., andWallesten, J. “Modeling of TurbulentFlames Expanding under ElevatedPressures in Combustion Bombs andInternal Combustion Engines”, NinthInternational Conference on NumericalCombustion, April 7-10, 2002,Sorrento, Italy. pp. 155-156.

147.Wallesten J., Lipatnikov, A.N., andChomiak, J. “Simulations of Fuel/AirMixing, Combustion, and PollutantFormation in a Direct Injectiongasoline Engine”, SAE Paper 2002-01-0835.

148.Lipatnikov, A.N. and Chomiak, J.“Transient and Curvature Effects whenDefining Burning Velocity and Speed ofPremixed Turbulent Flames”,Engineering Turbulence Modelling andMeasurements 5, Eds. by W. Rodi andN.Fueyo, Proceedings of the 5thInternational Symposium onEngineering Turbulence Modelling andMeasurements, Mallorca, Spain, 16-18September, Elsevier, 2002, pp. 853-862.

149.Pär Bergstrand, Michael Försth andIngemar Denbratt, “Investigation ofDiesel Spray Injection into HighPressure Conditions with ReducedNozzle Orifice Diameter”, JSAE20015324.

150.Pär Bergstrand, Michael Försth andIngemar Denbratt, “The Influence ofOrifice Diameter on Flame Lift-OffLength”, ILASS-Europe 2002.

151.Ganipa, L, manuscript in preparation.

152.Fredrik Persson, Michael Försth, andArne Rosén, “A Survey of Model FuelMixtures Suitable for Exciplex-Spectroscopy for Liquid/VaporVisualization”, Proceedings of the 18thAnnual Conference on LiquidAtomization & Spray Systems, ILASSEurope, (2002).

153.Mikael Skogsberg, manuscript inpreparation.

154.Pär Bergstrand, Fredrik Persson,Michael Försth and Ingemar Denbratt,”A Study of the Influence of NozzleOrifice Geometries on Fuel Evaporationusing Laser-Induced ExciplexFluorescence”, JSAE 20030217 (SAEPaper 2003-01-1836).

155.Stina Hemdal “Development of CavityRingdown Spectroscopy for FlameAnalysis: Application to Calibration ofLaser-Induced Fluorescence” MasterThesis 2002.

156.Bergstrand P., “Towards th End of theDiesel Dilemma”, Licentiate ThesisChalmers 2001.

157.Larsson S.: “Engine Control UsingTorque Sensors”. Control Meeting,Linköping University, June 2002.

158.Larsson, S.: "A Statistical Analysis ofPressure and Torque Measurements inaSI-engine. Working document.Chalmers, July 2002.

159.Larsson, S.: "SI-Engine Spark AdvanceControl Using Torque Sensors". Draftsubmitted to SAE 2003.

160.Schagerberg, S. and T. McKelvey:"Instantaneous Crankshaft TorqueMeasurements - Modeling andValidation”. SAE paper, 2003. Toappear.

161.Andreas Matsson, Sven Andersson”The Effect of Non-Circular NozzleHoles on Combustion and EmissionFormation in a Heavy-Duty DieselEngine ” SAE 2002-01-2671.

162.Lionel Christopher Ganippa, AndreasMatsson, Sven Andersson, and JerzyChomiak ”Combustion characteristicsof diesel sprays from equivalentnozzles with sharp and rounded inletgeometries”, Combustion Science andTechnology, accepted for publication.

163.Berg, E.v, Alajbegovic, A., Greif, D.,Poredos, A., Tatschl, R., Winklhofer, E.,Ganippa, L.C.(2002) Primary Break-UpModel for Diesel Jets Based on LocallyResolved Flow Field in the InjectionHole, Annual Conference on LiquidAtomization & Spray Systems-Europe,Sep. 9-11 Zaragosa.

164.Berg, E.v, Edelbauer, W., Tatschl, R.,Volmajer, M, Kegl, B., Alajbegovic, A.and Ganippa, L.C. (2003) Validation ofa CFD Model for Coupled Simulation ofNozzle Flow, Primary Fuel JetBreak-upand Spray Formation. ASME InternalCombustion Engine Conference,ICES2003-643, May 11 - 14, Salzburg.

165.Ganippa, L.C., Bark, G., Andersson, S.,and Chomiak, J: (2003a) “Cavitation: acontributory factor in the transitionfrom symmetric to asymmetric jets incross-flow nozzles” Experiments inFluids. (accepted for publication).

166.Ganippa, L.C., Matsson, A., Andersson,S. and Chomiak, J. (2003b)“Combustion Characteristics of DieselSprays from Equivalent Nozzles withSharp and Rounded Inlet Geometries”,Combustion Science and Technology,(in press).

167.Tao, Feng, ”Numerical Modeling of Sootand NOx Formation in Non-StationaryDiesel Flames with ComplexChemistry”, Ph.D thesis, Department ofThermo- and Fluid Dynamics, ChalmersUniversity of Technology (2003)

168.Wallensten, Johan, ”Modeling of FlamePropagation in Spark Ignition Engines”,Ph.D thesis, Department of Thermo-and Fluid Dynamics, ChalmersUniversity of Technology (2003)

169. Tao, Feng, Golovitchev, V.I., andChomiak, J., ”A PhenomenologicalModel for Prediction of Soot Formationin Diesel Spray Combustion”,Combustion and Flame (accepted)(2003)

170.Golovitchev, V.I., Atarashiya, K., Tanaka,L., and Yamada, S., ” Towards UniversalEDC-Based Combustion Model forCompression Ignited EngineSimulations”, SAE Paper 2003-01-1849 (2003)

171.Gustavsson, J., and Golovitchev, V.I., ”Spray Combustion Simulation Basedon Detailed Chemistry Approach forDiesel Fuel Surrogate Model”, SAEPaper 2003-01-1848 (2003)


172.Golovitchev, V.I., ”Compressible IgnitedEngine Modeling. The Possible RoadMap in Solving New Problems”,SAE_NA P6, Plenary lecture at theInternational Conference ICE 2003,Capri-Naples (September 18-21, 2003)

173.Golovitchev, V.I., Nordin, N., Dahlen, L.,Konstanzer, D., and Häggström, A.,”Numerical Simulation of Heat ReleaseRate in DI Diesel Engines at DifferentLoads”, SAE_NA 2003-01-75 (2003)

174.Golovitchev, V.I., and Ogink, R.,”Reaction Mechanisms for Natural Gasand Gasoline in Homogeneous ChargeCompression Ignition (HCCI) EngineModeling”, SAE_NA 2003-01-42 (2003)

175.Jasak H., Weller H., Nordin N., ”In-Cylinder CFD Simulation Using a C++Object Oriented Toolkit”, SAE 2004-01-0110

176.Fredrik Persson, Michael Försth, andArne Rosén, ”A Survey of Model FuelMixtures Suitable for Exciplex-Spectroscopy for Liquid/VaporVisualization”, Proceedings of the 18thAnnual Conference on LiquidAtomization & Spray Systems, ILASSEurope, (2002)

177 Larsson, S.: ”SI-Engine spark advancecontrol using torque sensors”.Licentiate thesis, June 2003. Technicalreport 470L.

178 Schagerberg, S.: ”Torque Sensors forEngine Applications” Licentiate thesis,Sep 2003. Technical report 472L.

179 Schagerberg, S. and T. McKelvey:”Instantaneous Crankshaft TorqueMeasurements - Modeling andValidation. SAE Technical paper no.2003-01-0713, March 2003.

180 Larsson, S. and B. Egardt: ”SI-EngineSpark Advance Control Using TorqueSensors”, IFAC Advances in automotivecontrol, Salerno, Italy, 2004.

181 Larsson, S. and S. Schagerberg: ”SI-Engine cylinder pressure estimationusing torque sensors”, SAE Technicalpaper no. 2004-01-1369, March 2004.

During 2004.

Modeling of Spray Formation, Ignition and Combustion in Internal Combustion Engines

182 Gustavsson,J., and Golovitchev,V.I., 3DSimulations of Multiple Injections in DIDiesel Engine. Paper A8-1,Proceedings of COMODIA 2004, August2-5, Yokohama, p.167 (2004)

183 Golovitchev,V.I., Analysis ofAssumptions Commanding DetailedChemistry EDC Based Model for DieselSpray Combustion. Paper A8-2,Proceedings of COMODIA 2004, August2-5, Yokohama, p.175 (2004)

184 Corcione, F., Golovitchev,V.I., Costa, M.,and Allocca, L., Study of MultipleInjections and Auto-Ignition of DieselSprays in a Constant Volume Vessel,Paper C7-3, Proceedings of COMODIA2004, August 2-5, Yokohama, p.567(2004)

185 Gustavsson,J.,Golovitchev,V.I., andHelmantel, A., 3D Modeling ofConventional and HCCI CombustionDiesel Engine, SAE Paper 04FFL-130(2004)

186 Golovitchev,V.I., Rente, T., andDenbratt, I., Computational andExperimental Study of MK Diesel SprayCombustion. Accepted for publicationin International Journal of VehicleDesign (2004)

187 Häggström, A. “Modelling andSimulation of Diesel Sprays:Lagrangian Multicomponent FuelTreatment”, Thesis for the Degree ofLicentiate in Engineering, CTH,Göteborg (2004)

188 A. Magnusson, S. Andersson and N.Nordin, “A Comparison of Experimentsand Numerical Calculation of DieselSpray Behaviour”, VAFSEP Dublin2004, pp 42-47

189 H. Jasak, H.G. Weller and N. Nordin,“In-Cylinder CFD Simulation Using aC++ Object-Oriented Toolkit”, SAEPaper 2004-01-0110

Spray-Guided Gasoline DirectInjection

190 Skogsberg, M., P. Dahlander, F.Persson, S. Hemdal, and I. Denbratt,Fuel distribution visualization from anair assisted injector in a spraychamber using LIF, MIE, Direct imagingand PDA. JSME No.04-202, No. C3-2,2004.

191 Skogsberg, M., P. Dahlander, R.Lindgren, and I. Denbratt, Effects ofinjector parameters on mixtureformation for multi-hole nozzles in aspray-guided gasoline DI engine. SAETechnical Paper Series, No. 2005-01-0097, 2005

192 Skogsberg, M. Experimentalcharacteristics of spray-guidedgasoline DI sprays. Thesis for thedegree of Licentiate in Engineering.Technical Report no 2005:2,Department of Applied Mechanics,Chalmers University of Technology,ISSN 1652-8565, 2005.

193 Kindström, J. Optical Engine Flow FieldMeasurements for a Modified CylinderHead Using PIV and Designing andManufacturing of a Variable Swirl andTumble System. Diploma work 04/26,Division of Thermo and FluidDynamics, Chalmers University ofTechnology, 2004

Optical Two-Phase diagnistics194 Fredrik Persson, Michael Försth, and

Arne Rosén, “A Survey of Model FuelMixtures Suitable for Exciplex-Spectroscopy for Liquid/VaporVisualization”, Proceedings of the 18thAnnual Conference on LiquidAtomization & Spray Systems, ILASSEurope, (2002)

195 Fredrik Persson, “Studies of the Laser-Induced Exciplex FluorescenceTechnique for Applications in Spray

Research”, Lic. thesis, ChalmersUniversity of Technology, 2004.

196 S. Hemdal, Å. Johansson, M. Försth, M.Andersson, and A. Rosén, “Reactionintermediates in high temperaturecatalytic water formation studied withcavity ringdown spectroscopy”, J. Vac.Sci. Technol. A 22, 1620 (2004).

197 Jens Ekengren and Johan Sjöholm,“Cavity ringdown spectroscopy for sootdetection in premixed and diffusionatmospheric flames” Diplomadissertation, Chalmers University ofTechnology, 2005.

Theoretical and ExperimentalInvestigations of Combustion ofShort Duration Small DiameterSprays in Diluted Air

198 Ehleskog, R. and Andersson, S.,Numerical and experimentalinvestigation of fuel propertiesinfluence on the dynamic behaviour ofa diesel injection system. In AbdulGhani Olabi, editor, VehiclesAlternative Fuel Systems &Environmental Protection, pages 60–65. VAFSEP, Dublin City University, jul2004.

199 Ehleskog, Rickard and Andersson,Sven, Experimental investigation ofspray behaviour and spray interactionfor diesel multiple injectionapplication. In Barry J Azzopardi,editor, 19th Ilass Europe ’04, pages308–313. ILASS-Europe, University ofNottingham, Sept. 2004.

Torque sensors for engineapplications

200 Larsson, S. and S. Schagerberg: “SI-Engine cylinder pressure estimationusing torque sensors”, SAE Technicalpaper no. 2004-01-1369, March2004.

201 Larsson, S. and B. Egardt: “SI-EngineSpark Advance Control Using TorqueSensors”, IFAC Advances inautomotive control, Salerno, Italy,2004.

202 I. Andersson and T. McKelvey, “TorqueRatio Concept for CombustionPhasing Detection of a Spark IgnitedEngine”, IEEE CDC2004 paper WeA09-5, December 2004.

203 I. Andersson and T. McKelvey, “ASystem Inversion Approach on aCrankshaft of an Internal CombustionEngine”, IEEE CDC2004 paperFrC12-1, December 2004.

204 Larsson, S. and I. Andersson: “Anexperimental valuation of torquesensor based feedback control ofcombustion phasing in an SI-engine”,SAE Technical paper no. 2005-01-0060, April 2005.

Editor..........Sivert Hiljemark

Layout....................Hagal AB

Print........Litorapid Media AB

Göteborg - Sweden-2005

The Competence Centre in Internal Combustion Engines

(Combustion Engine Research Center – CERC) was established at

Chalmers University of Technology in co-operation with Swedish

engine manufacturers and the Swedish Board of Technical and

Industrial Development (NUTEK) in 1995. 1997 the co-

ordination is transferred to the Swedish National Energy

Administration. The aim of the centre is to strengthen

the activities concerning the relevant basic industrial research

associated with Internal Combustion Engines.

CERC concentrates on research aiming for reductions both of fuel

consumption and engine exhaust emissions. The projects at the

centre include both experimental validation of models and

systems and new concepts associated with alternative fuels.

Furthermore, new diagnostic tools are used in engine research.

Several projects concentrate on different types of spray formation,

spray diagnostics and flame propagation. Strong competence in

thermodynamics, mass and heat transport, kinetics and

measurement techniques will be built up.

CERC

CERCChalmers University of Technology

SE-412 96 GöteborgSweden

Telephone +46 (0)31-772 1820

Fax +46 (0)31-18 09 76E-mail [email protected]

Internet www.tfd.chalmers.se/CERC/

annual report 2004 · 2007. 1. 12. · 2 cerc – annual report 2004 cerc combustion engine...

Documents