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“ERC Research on Advanced Fueling Strategies for High Efficiency, Low Emission Engines”

Rolf D. ReitzEngine Research Center

University of Wisconsin-Madison

http://www.erc.wisc.edu/

Acknowledgements: Industry Partners: Direct-injection Engine Research Consortium members, Caterpillar, Ford, General Motors. Sandia, Argonne, Oak Ridge National Labs,ARO, DOE, NASA, ONR, Princeton CEFRC.- ERC faculty, staff and students

Engine Research Center2

Founded in 1946 ~70 years ago! Largest academic research center focusing on internal combustion

engines in the U.S. ~$3 million annual research budget – 7 active faculty

- 50-50% Federal-Industry funding, - Direct-injection Engine Research Consortium (DERC) - 36 members

Over 50 graduate students, 10-15 post-docs and visiting scholars, 8-10 research and administrative staff

Engine research– Primary focus is engine performance, combustion, emission control– Diesel, spark-ignition and advanced combustion engine research

• Major themes- Education of students- Use of real engines and diagnostics- Emphasis on interaction between experiments and modeling- Interaction with practicing engineers

Engine Research Center


Development of today’s fuels (1910-1970)

“Early” history of ERC research (1946-1995)

ERC research in advanced fueling strategies– Multiple injections (1994)– Gasoline compression ignition (2001)– Dual fuel RCCI (2009)– Dual injector, dual fuel strategies (2014-15)

Conclusions and future research directions

Outline


Boyd T (1950) Pathfinding in Fuels and Engines. SAE 500175, 4(2) 182-195.

Ignitability affects engine efficiency - limits compression ratio (CR).

Early Spark Ignition (SI) engines were plagued by “spark knock”, CR ~ 4:1.

Cylinder pressure measurements by Midgley and Kettering at DELCO/GM showed different fuels had different knock tendency

e.g., kerosene worse than gasoline

Volatility differences were thought to be the explanation.

Guided by the “Mayflower,” they added a red dye (iodine) to kerosene and knock tendency was greatly reduced!

Unfortunately, tests with other red dyes didnot inhibit knock, disproving the theory.

But, finding powerful antiknock additives was a major serendipitous discovery!

Mayflower – Trailing Arbutus Janein early spring

Lessons from history (1910-20) – “the Mayflower”


Research after WW-I was motivated by national security - Improved fuel efficiency with higher CRs made possible the first

non-stop airplane flight from New York to San Diego in the 1920’s.

GM and US Army studied hundreds of additives and found aromatic amines to be effective knock suppressors.

1920 experimental GM car driven on gasoline with toluidine with CR ~7:1 - 40% better fuel consumption than 4:1.

Engine exhaust plagued by unpleasant odors

Lessons from history (1920-30) – the Amines and TEL

Reitz, Front. Mech. Eng. 1:1, 2015

Much research was devoted to find acceptable additives, - finally leading to tetraethyl lead (TEL)

But, TEL caused solid deposits, damaged exhaust valves and spark plugs.Scavenger additives with bromine and chlorine corrected the problem.

- Partnership with Ethyl-Dow and DuPont to extract compounds from sea water - 10 tons of sea water needed to provide 1 lb of bromine!

- “the goat”!

WW-II aviation engines used iso-heptane (triptane: 2,2,3-trimethyl butane) - allowed CR as high as 16:1.


Lead poisoning was an early concern - In 1926 US Surgeon General determined that TEL poses no health hazards.- Use of lead in automotive fuels has been called “The mistake of the 20th century”

1950: Dr. Arie Haagen-Smit - cause of smog in LA to be HC/NO - Cars were the largest source of UHC/NOx

1950: Eugene Houdry - developed catalytic converter for auto exhaust. - But, lead was found to poison catalytic converters.

20 years later: US EPA announces gas stations must offer "unleaded" gasoline,- Based accumulated evidence of negative effects of lead on human health. - Leaded gasoline was still tolerated in certain applications (e.g., aircraft),

but was permanently banned in the US in 1996, in Europe since 2000

Lessons from history (1930-70) –TEL and the future

Reitz, Front. Mech. Eng. 1:1, 2015

World Wars & national security played a major role to define automotive fuels.

Today’s engines and their fuels would not have been developed without close collaboration between engine OEMs, energy and chemical companies!

A consequence of collaboration between “big” engine and “big” oil is that transformative changes in transportation systems will not occur easily.

A new concept engine must be able to use available fuels, A new fuel must run in existing engines.






Outline

8 Engine Research Center

“Race between compression ratio and octane number”

E. Curtis, 2013

ERC: diesel focus Advanced comb.

WW-II

muscle car:miles/$

clean air act

opec


1930s Profs. G.C. Wilson and R.A. Rose - Pioneered work on pressure pickups and reduction of diesel ignition delay

via use of fuel additives.1942, post-WW-II Profs. P.S. Myers ME*47 and O. Uyehara ChE*45

- studied under Profs. L.A. Wilson and K.M. Watson- 2-color pyrometry in a Fairbanks Morse engine equipped with a window

Uyehara, O.A., Myers, P.S., “Diesel Combustion Temperatures – The Influence of Fuels of Selected Composition,” SAE Trans., Vol. 3, No. 1, pp. 178-199, 1949.

- Led to a $50K WARF grant plus housing in T-25 "war surplus" building andCRC contract to measure end-gas temperatures in SI engines with iodine spectra absorption

Chen, S.K., Beck, N.J., Uyehara, O.A., and Myers, P.S., “Compression and end gas temperatures from iodine absorption spectra,” SAE Trans. 503–526 (1954)

“Phil Anotto” retired ~1986 and produced 48 PhDs and 80 MS graduates

http://www.erc.wisc.edu/theses.php

“A Brief History of Engine Research at the University of Wisconsin-Madison 1946-1995” by G.L. Borman*57

2015: ERC has produced over 500 graduates

www.erc.wisc.edu/documents/BormansERC-Review.pdf

http://www.erc.wisc.edu/theses.php


1949-52 Ignition improvers – Army fuels1949 Emissions - Diesel smoke1951 Drop vaporization1959-63 Heat flux-radiation measurements1962 Super-critical environments1964 Pressure heat release rate1966 End gas knock1977 Total cylinder contents dumping (NOx)1981 Compression-Ignited Homogeneous Charge

Combustion 1982 UHC sampling probe

measurements correlated with model predictions1986 ERC named ARO Center of Excellence for Advanced Propulsion1991 3-D CFD modeling for engine development1991-94 Diesel multiple injection

Major Technologies: Engine diagnostics, drop and spray vaporization, combustion, emissions,chemical kinetics, cycle and CFD modeling, fuels, heat transfer

“A Brief History of Engine Research at the University of Wisconsin-Madison 1946-1995” by G.L. Borman*57

Najt & Foster SAE 830264

Krieger & Borman ASME 1966

Nehmer & Reitz SAE 940668

Johnson, Myers & Uyehara, SAE 1966

Reitz & Rutland SAE 911789

www.erc.wisc.edu/documents/BormansERC-Review.pdf






Outline


ERC: Advanced fueling strategies – multiple injectionsNehmer & Reitz SAE 940668Tow, Pierpont & Reitz SAE 940897Pierpont, Montgomery & Reitz

SAE 950217

1994: Nehmer, D.A., MSMeasurement of the Effect of Injection Rate and Split Injections On Diesel Engine Soot and NOx Emissions

1994: Tow, T., MSThe Effect of Multiple Pulse Injection, Injection Rate and Injection Pressure on Particulate and NOx Emissions from a D.I. Diesel Engine

1994: Pierpont, D.A., MSAn Experimental Study of the Effect of Injection Parameters and EGR on D.I. Diesel Emissions and Performance

[S1]

[D1]

[D2]

[D3]

[D4]

l

l

l l l

H

H

HH H

T

T

TT T

:

:

:: :

G

G

G G

0.020.04

0.060.08

0.10.120.140.160.180.2

3 4 5 6 7 8 9

Part

icul

ate

(g/b

hp-h

r)

NOx (g/bhp-hr)

l [S1] Single .6H [D1] 13-(0)-87T [D2] 16-(0)-84: [D3] 21-(0)-79G [D4] 32-(0)-68

Common-rail injector90MPa injection pressure125 degree spray angle1600 rev/min,75% load

Single injections Han et al. SAE 960633

Split injections

Engine Emissions vs Start of Injection Timing700 RPM PHI=0.22

0

20

40

60

80

100

120

-360 -300 -240 -180 -120 -60 0

Injection Angle (deg ATDC)

CO a

nd U

HC E

mis

sion

s (g

/kg-

fuel

)

0

3

6

9

12

15

18

CO

UHC

NOx

Particulate Matter PM a

nd N

Ox

Emis

sion

s (g

/kg-

fuel

)


ERC: Advanced fueling strategies – fuels and split injectionMarriott & Reitz SAE 2002-01-0418Canakci & Reitz IJER 2003Hanson et al. SAE 2009-01-1442Dempsey & Reitz SAE 2011-01-0356Ra et al. SAE 2011-01-1182

2001: Marriott, Craig D. MSAn Experimental Investigation of Direct Injection for Homogeneous and Fuel-Stratified Charge Compression Ignited Combustion Timing Control

Gasoline-fueled HD diesel engine - Low pressure common rail, hollow cone injector- GCI, PFS, PPC, ….

HCCI Stratified

Marriott & Reitz US Patent 6,668,789 – 2003

0

5

10

15

20

25

30

35

40

700 900 1100 1300 1500 1700 1900Engine Speed (rev/min)

NOx

Emis

sion

s (g

/kg-

fuel

)

85

88

91

94

97

Single Injection NOx Split Injection NOxSingle Injection Comb. Eff. Split Injection Comb. Eff.

Com

bust

ion

Effic

ienc

y (%

)

NOx Emission and Combustion Efficiency Comparison: Single vs Split Injections

Intake Air Temp = 119 C PHI = 0.21

SOI 300100o: SOI1 ~180o (60%); SOI2 ~90o

∆P~100bar

Kalghatgi et al. SAE 2007-01-0006

ERC: Advanced fueling strategies - diesel vs. gasoline Ra et al., "Parametric Study of Diesel Engine Operation with Gasoline," Combustion Science and Technology, Vol. 181, No. 2, pp.350-378, 2009

Engine Research Center

Engineheavy-duty, flat cylinder

head, shallow bowl

Bore x Stroke [mm] 127 x 154

Compression ratio 14.0

Injector hole, dia [µm] 8, 200

Engine speed [rpm] 1200

Swirl ratio 2.4

Intake temp [C], Pressure

[bar]

40, 2.0

Oxygen @ IVC/EGR [%] 15.8/25

Pilot split ratio [%] 30

Diesel vs. gasoline - emissions

Additional time for mixing with gasoline offers significant benefit for soot reduction in CIDI engines

0

0.05

0.1

0.15

0.2

0.25

0.3

-30 -20 -10 0 10 20start of main injection

calc

ulat

ed s

oot [

g/kg

-f]

0

2

4

6

8

10

12

14

16

18

AVL

sm

oke

opac

ity [%

]

Gasoline, calDiesel, calGasoline, expDiesel, exp

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

-30 -20 -10 0 10 20start of main injection [deg atdc]

NO

x [g

/kg-

f]

Gasoline, calGasoline, expDiesel, calDiesel, exp

diesel

gasoline

Soot

NOx


Marriott et al. SAE 2002-01-0419Ra et al. CST 2009

Vishwanathan & Reitz CST 2010

6 bar IMEP, 1300 rpm

0 10 20 30 40 50 600

20

40

60

80

100

250

180 g/kW-hr

MISFIRE

190g/kW-hr

PRF

[-]

EGR Rate [%]

10 bar/deg.

5.6 bar/deg.

Combustion optimization - fuel and EGR selectionHCCI simulations used to choose

optimal EGR rate and PRF (isooctane/n-heptane) blend

Predicted contours agree well with HCCI experiments

Fuel reactivity must change with EGR rate for optimum ISFC

As load is increased the minimum ISFC cannot be achieved with either neat diesel fuel or neat gasoline

170

190

210

230240

Net ISFC [g/kW-hr]

EGR Rate [%]

PRF

Kokjohn et al. SAE 2009-01-2647

Gasoline-diesel“cocktail”

Gas

olin

eD

iese

l


ERC PRF mechanismRa & Reitz, CNF 2008


Direct injected dieselPort injected gasoline

Diesel-80 to -50 -45 to -30

Crank Angle (deg. ATDC)

Inje

ctio

n Si

gnal

Squish Conditioning

Ignition Source

Gasoline

Diesel

Gasoline

Optimized Reactivity Controlled Compression Ignition

CFD with Genetic Algorithms used to optimize multiple injection strategy

GA: Senecal & Reitz SAE 2000-01-1890

Kokjohn et al. SAE 2009-01-2647

ERC: Heavy- and light-duty experimental engines

Engine Heavy Duty Light Duty

Engine CAT SCOTE GM 1.9 L

Displ. (L/cyl) 2.44 0.477

Bore (cm) 13.72 8.2

Stroke (cm) 16.51 9.04

Squish (cm) 0.157 0.133

CR 16.1:1 15.2:1

Swirl ratio 0.7 2.2

IVC (°ATDC) -85 and -143 -132

EVO(°ATDC) 130 112

Injector type Common rail

Nozzle holes 6 8

Hole size (µm) 250 128

LDHD

Engine size scalingStaples, SAE 2009-01-1124


IMEP (bar) 9

Speed (rpm) 1300

EGR (%) 43

Equivalence ratio (-) 0.5

Intake Temp. (°C) 32

Intake pressure (bar) 1.74

Gasoline (% mass) 76 82 89

Diesel inject press. (bar) 800

SOI1 (°ATDC) -58

SOI2 (°ATDC) -37

Fract. diesel in 1st pulse 0.62

IVC (ºBTDC)/Comp ratio 143/16

Computer modeling predictions confirmedCombustion timing and Pressure Rise Rate control with diesel/gasoline ratio

Effect of gasoline percentage

Hanson et al. SAE 2010-01-0864

-30 -20 -10 0 10 20 300

2

4

6

8

10

12

14 Experiment Simulation

Crank [°ATDC]

Pres

sure

[MPa

]

0

200

400

600

800

1000

1200

1400

89%Gasoline

76%

82%

89%

App

aren

t Hea

t Rel

ease

Rat

e [J

/°]

NeatGasoline

NeatDiesel Fuel

Dual-fuel can be used to extend load limits of either pure diesel or gasoline

Experimental validation - HD Caterpillar SCOTE


4 6 8 10 12 14 164548515457

0.000.010.020.030.00.10.20.3

Heavy-duty RCCI (gas/gas+3.5% 2-EHN, 1300 RPM)Heavy-duty RCCI (E-85/Diesel, 1300 RPM)Heavy-duty RCCI (gas/diesel 1300 RPM)

Gro

ssIn

d.Ef

ficie

ncy

Gross IMEP [bar]

Soot

[g/k

W-h

r]

HD Target (~2010 Levels)

NO

x[g

/kW

-hr]

HD Target (~2010 Levels)

RCCI – high efficiency, low emissions, fuel flexibility

Splitter, SAE 2010-01-2167; Hanson, SAE 2011-01-0361, Kokjohn IJER 2011

Indicated efficiency of 58±1%achieved with E85/diesel

Emissions met in-cylinder, without need for after-treatment

Considerable fuel flexibility,including ‘single’ fuel operation

Diesel can be replaced with <0.5% total cetane improver (2-EHN/DTBP) in gasoline- less additive than SCR DEF


Dual-fuel RCCI combustion – controlled HCCI

Heat release occurs in 3 stages Cool flame reactions from diesel (n-heptane) injectionFirst energy release where both fuels are mixedFinal energy release where lower reactivity fuel is locatedChanging fuel ratios changes relative magnitudes of stagesFueling ratio provides “next cycle” CA50 transient control

21-20 -10 0 10 20

0

50

100

150

200

Crank [oATDC]

AH

RR

[J/o ]

Primarly iso-octane

n-heptane+ entrained iso-octane

Iso-octane BurnPRF BurnCool Flame

Primarly n-heptane

80 90 100 110 120 130 140 150 160 17055

60

65

70

75

80

85

90

95

Intake Temperature [oC]

Del

iver

y R

atio

[% is

o-oc

tane

]

d(Del i ver yRati o)d(I nt:Temp:)

= 0:4per cent

KCA50=2 ˚ ATDC

RCCISOI = -50 ATDC

RCCI

Reitz et al. US Patent 8,616,177 - 2013



GM 1.9L Engine Specifications

Multi-cylinder RCCI - transient operation

Engine Type EURO IV DieselBore 82 mm Stroke 90.4 mm Displacement 1.9 liters Cylinder Configuration

Inline 4 4 valves per cylinder

Swirl Ratio Variable (2.2-5.6)Compression Ratio 17.5

EGR System Hybrid High/Low Pressure, Cooled

ECU (OEM) Bosch EDC16 ECU (new) Drivven

Common Rail Injectors

Bosch CRIP2-MI 148° Included Angle7 holes,440 flow number.

Port Fuel Injectors

Delphi2.27 g/s steady flow400 kPa fuel pressure

UW RCCI Hybrid Vehicle

SAE Paper 2015-01-0837

Highway Fuel Economy Testing of an RCCI Series Hybrid VehicleReed Hanson, Shawn Spannbauer, Christopher Gross, Rolf D. Reitz, University of Wisconsin; Scott Curran, John Storey, Shean Huff, ORNL


RCCI operating range – ORNL & ERC

Load expansion via alternativefuels, VVA, dual direct injection, …..

. UDDS/FTP cycle

RCCI offers diesel-like or better BTE across speed-load range

ORNL simulations indicate RCCI offers >20% fuel economy c.f. 2009 PFI engines

Wagner, Aramco Workshop, 2014

ERC: Advanced fueling strategies – RCCI load expansion

Direct injection of both diesel and gasoline Stock piston geometry has 2 zones:

- Squish with high surface/volume ratio, - bowl with low S:V ratio


Lim and Reitz ASME GTP, 136, 2014Lim and Reitz SAE 2014-01-1320

High load/speed simulations ERC KIVA3V-R2, GA optimizationDiscrete Multi-Component fuel evaporationERC PRF mechanism

- 46 species, 142 reactionsGasjet model for reduced grid dependencyBoth injectors at cylinder axis

HD RCCI engine: 21 bar IMEP gasoline/dieselIVC conditions: 3.42 bar, 90°C, 46%EGR

2015: Lim, J., PhDHigh Power Output Operation of RCCI Combustion

ERC: Advanced fueling strategies – DDFS strategy


Caterpillar 3401 SCOTECR=14.9

2015: Wissink, M.L., PhDDirect Injection for Dual Fuel Stratification (DDFS):Improving the Control of Heat Release in Advanced IC Engine Combustion Strategies

Wissink & Reitz SAE 2015-01-0856

RCCI

PPC

PPC

DDFS

ERC: Advanced fueling strategies – DDFS emissions


0

More final late-injected fuel

EPA 2010

ERC: Advanced fueling strategies – DDFS efficiency


~14% reduction ~12% reduction

~1% increase

~30% increase

~13% reduction

DDFS provides high efficiency, lower noise/COV, lower heat loss/increased exhaust loss – reducing turbo requirements

Conclusions and future research directionsAdvanced combustion strategies (e.g., GCI, RCCI and its variants) offer

practical low-cost pathways to >15% improved internal combustion engine fuel efficiency (lower CO2)

Made possible by advances in fuel injectors and computer control

RCCI GTEs in the 58-60% range achieved − within ~94% of theoretical cycle.

Inconvenience of two fuels already accepted by diesel industry (diesel/DEF)RCCI is cost effective and offers fuel flexibility:

- low cost port-injected less reactive fuel (e.g., gasoline, E85, “wet” EtOH, C/LNG) with optimized low pressure DI of more-reactive fuel (e.g., diesel/additized gas)

- reduced after-treatment needed - meet NOx and PM emission mandates in-cylinder- diesel or SI (w/spark plug) operation can be retained (e.g., mixed mode, limp home).

Improved transient control:- proportions of low and high reactivity fuels can be changed dynamically, with same/next-

cycle combustion feedback controlDirect injection of both fuels allows more control of heat release:

- reduced noise, reduced cyclic variability, no efficiency penalty, move waste heat to exhaust

Future directions:- transient engine feedback control, load extension (e.g., via: multiple injection, CR, VVA),- optimized pistons – reduced crevice volumes, insulated pistons.- optimized boost, EGR, charge-air cooling, alternative fuels……

.. and vehicle testing!

28 Engine Research Center, 2013

Splitter et al. SAE 2013-01-0279

2025 and beyond….Voyage to new concepts in engine combustion

California ARB:90% reduction in NOx emissions by 2031 (0.02 g/bhp·hr)80% reduction in GHG emissions (below 1990 levels) by 2050 Governor’s 50% petroleum reduction target by 2030 (renewable fuels), and continued reductions in air toxics & diesel PM (PN 6×1011 1/km).

Backup

High load GA optimization – 21 bar IMEP

NOx [g/kW-hr] 0.026

Soot [g/kW-hr] 0.078

CO [g/kW-hr] 4.4

UHC [g/kW-hr] 2.7

Gross ITE [%, IVC-EVO] 46.0

Gross ITE [%, BDC-BDC] 48.2

CAD @ 10% HR [ATDC] 7.0

CAD @ 50% HR [ATDC] 16.0

CAD 10-90% HR 13.0

Max Pressure [bar] 169.7

PPRR [bar/deg] 12.6

Iso-octane 1 [mg, °ATDC] 149.8 @ -115.6

Iso-octane 2 [mg, °ATDC] 87.8 @ -21.0

N-heptane [mg, °ATDC] 7.4 @ -3.0


Dual fuel, direct injection offers high load, high efficiency operation potentialDual fuel RCCI offers high power with medium load high speed operation

Lim and Reitz ASME GTP, 136, 2014Lim and Reitz SAE 2014-01-1320


Limits of dual fuel RCCI efficiency

Exp. GT POWER

GT POWER

Compression ratio 14.88 14.88 18.6

IMEPn (bar) 8.00 7.86 8.69

Fueling (mg/cyc) 87.13 87.13 87.13

Gross Therm Eff. (%) 54.3 54.5 59.7

Net Therm Eff. (%) 52.0 52.1 57.5

BTE (%) 45.3 45.1 49.1

FMEP (bar) 1.03 1.0 1.2Convection HX N/A 0.4 0.2Comb. Eff. (%) 98 98 99Intake Pressure (bar) 1.5 1.5 1.68Exhaust Pressure (bar) 1.625 1.625 1.75Turbo eff. (air filter + DOC)

67.5 62.3 72.8

Calibrate 0-D code with experimental dataUse to determine:

- initial conditions - geometry

Results:60% GTE possible with:High Cr Lean operation (Φ<0.3)50% reduction in heat transfer &combustion losses

• Deactivate under-piston oil jet cooling

Splitter et al. SAE 2013-01-0279

High efficiency demonstrated

Simulation heat transfer tuned to match data

- 14.88:1 Piston required HX = 0.4

- 18.7:1 required HX = 0.3Pancake design ~1.2 less

surface area18.7:1 without oil cooling

required HX = 0.2

GTE (%) IMEPg (bar) NTE (%) IMEPn

(bar) EXP (pt. 83) 59.1 6.82 55.0 6.27 GT Power HX =0.2 58.8 6.79 54.8 6.25 GT Power HX =0.4 56.7 6.55 52.8 6.02

GTE(%)

IMEPg(bar)

NTE(%)

IMEPn(bar)

Experiment 59.1 6.82 55.0 6.27Model, HX =0100% comb. η 62.4 7.12 58.5 6.85

Model, HX =0100% comb.η,0% EGR

63.4 7.23 61.0 6.95

94% of maximum theoretical cycle efficiency achieved !

-40 -30 -20 -10 0 10 20 30 40-15

0153045607590

105120135150

E85 / 3% EHN+91 PON RCCI43°C intake, 42% EGR, 6.3 bar IMEPn

EXP, Squirter off, 43% EGR, Oil Matrix Point 83 GTPower, HX=0, 100% comb. η, 43% EGR GTPower, HX=0, 100% comb. η, 0% EGR

Pres

sure

(bar

)

Crank Angle (°CA ATDC)

0

150

300

450

600

750

AHR

R (J

/° CA

)

Splitter et al. “RCCI Engine Operation Towards 60% Thermal Efficiency”, SAE 2013-01-0279


Ultra high efficiency, dual fuel RCCI combustion

DI: 3%EHN+91ONPFI: E85TIVC = 43 CEGR = 42%

Operating Condition Low-Load

Mid-Load High-Load

Gross IMEP [bar] 4 9 11 13.5 16 23

Engine Speed [rpm] 800 1300 1370 1460 1550 1800

Intake Press. [bar abs.] 1.00 1.45 1.94 2.16 2.37 3.00

Intake Temp. [°C] 60 60 60 60 60 60

Caterpillar 3401E SCOTEDisplacement [L] 2.44Bore x Stroke [mm] 137.2 x 165.1Con. Rod Length [mm] 261.6Compression Ratio 16.1:1Swirl Ratio 0.7IVC [deg ATDC] -143EVO [deg ATDC] 130

Common Rail Diesel Fuel InjectorNumber of Holes 6Hole Diameter [μm] 250Included Spray Angle 145

o

Design Parameter Minimum MaximumPremixed Methane [%] 0% 100%DI Diesel SOI 1 [deg ATDC] -100 -50DI Diesel SOI 2 [deg ATDC] -40 20Diesel Fraction in First Inj. [%] 0% 100%Diesel Injection Pressure [bar] 300 1500EGR [%] 0% 60%

Natural gas/diesel RCCI

ERC KIVA PRF kineticsNSGA-II MOGA

32 Citizens per generation~9500 Cells @ BDC

UW Condor -Convergence after ~40 genrtns


Nieman, 2012RCCI Fuel flexibility – Alternative fuels

Double vs. triple injection

Results 2 Inj. Optimum 3 Inj. OptimumSoot [g/kW-hr] 0.004 0.004NOx [g/kW-hr] 0.24 0.10CO [g/kW-hr] 10.8 7.3UHC [g/kW-hr] 10.5 3.8ηgross [%] 45.1% 47.1%

4 bar IMEP 23 bar IMEP

Results 2 Inj. Optimum 3 Inj. OptimumSoot [g/kW-hr] 0.079 0.014NOx [g/kW-hr] 0.08 0.17CO [g/kW-hr] 6.0 1.7UHC [g/kW-hr] 9.4 3.3ηgross [%] 44.1% 46.5%

44.1% 42.4%

7.9% 5.6%

46.5%43.0%

8.5% 2.0%0%5%

10%15%20%25%30%35%40%45%50%

Gross Work Exhaust Loss Heat Transfer Combustion Loss

% o

f Fue

l Ene

rgy

In2 Inj. Optimum3 Inj. Optimum45.1%

31.5%

17.1%

6.3%

47.1%

31.9%

18.7%

2.4%0%5%

10%15%20%25%30%35%40%45%50%

Gross Work Exhaust Loss Heat Transfer Combustion Loss

% o

f Fue

l Ene

rgy

In

2 Inj. Optimum3 Inj. Optimum


Nieman MS 2012RCCI Fuel flexibility – Alternative fuels

0° ATDC2° ATDC4° ATDC6° ATDC8° ATDC10° ATDC12° ATDC14° ATDC16° ATDC

• Achieve low soot, despite late 3rd injectiono Combustion starts in squish region, so diesel #3 injects

into a relatively cool environmento Fairly small amount injected

18° ATDC

(Isosurface = 1600K)Isosurface

23 bar IMEP, triple Injection


Nieman MS 2012RCCI Fuel flexibility – Alternative fuels

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