a study of the feasibility and possible impact of …emission standards for heavy duty diesel...
TRANSCRIPT
TRANSPORT A N D ROAD RESEARCH LABORATORY Department of Transport
RESEARCH REPORT 158
A STUDY OF THE FEASIBILITY AND POSSIBLE IMPACT OF
REDUCED EMISSION LEVELS FROM DIESEL ENGINED
VEHICLES
by S Latham (TRRL) and P R Tonkin (Ricardo Consult ing Engineers plc)
The views expressed in this report are not necessarily those of the Department of Transport
Vehicles and Environment Division Vehicles Group Transport and Road Research Laboratory Crowthorne, Berkshire, RG11 6AU 1988
ISSN 0266-5247
Ownership of the Transport Research Laboratory was transferred from the Department of Transport to a subsidiary of the Transport Research Foundation on 1 st April 1996.
This report has been reproduced by permission of the Controller of HMSO. Extracts from the text may be reproduced, except for commercial purposes, provided the source is acknowledged.
CONTENTS
Abstract
1. Introduction
2. Heavy duty diesel usage--current and projected trends 1
3. Current and proposed exhaust emission regulations and test methods 2
4. Emission levels selected for study 3
5. Noise control legislation 4
6. Review of gaseous emission reduction techniques 4
6.1 NOx reduction 4
6.2 Hydrocarbon reduction 4
6.3 Unregulated pollutant reduction 4
7. Review of particulate emission reduction techniques 7
7.1 Effects of fuel composition 9
7.2 In engine reduction techniques 9
7.3 After-treatment techniques 11
8. The impacts of the seven selected emission levels on heavy duty diesel engines 11
8.1 Level 1 (current ECE Reg 24 and ECE Reg 49 limits) 12
8.2 Level 3 (20% reduction for NOx and 30% reduction for HC and smoke from level 1) 12
8.3 Level 7 (63% reduction for NOx and 50% reduction for HC from level 1, 0.1 g/bhp particulate limit) 12
9. Enforcing legislation 12
10. Conclusions 13
11. Reference 13
12. Acknowledgement 13
Appendix A. Bibliography 13
© CROWN COPYRIGHT 1988 Extracts from the text may be reproduced,
except for commercial purposes, provided the source is acknowledged
Page
1
1
A STUDY OF THE FEASIBILITY AND POSSIBLE IMPACT OF REDUCED EMISSION LEVELS FROM DIESEL ENGINED VEHICLES
ABSTRACT
A literature review was carried out to study the technical and economic implications of the introduction in Europe of more stringent exhaust emission standards for heavy duty diesel engines. Trends in engine type and usage and in the quality of diesel fuel, existing and proposed exhaust emission and noise control legislation in Europe, Japan and the USA and methods of reducing the gaseous and particulate emissons from diesel engines were reviewed. The information was used to assess the technology which would be required to achieve seven progressively more severe levels of emission control. All but the most severe level of control were considered achievable using existing technology, although this technology has not been proven in service. The most severe level, which assumed a very low permissible particulate emission rate, would necessitate the use of particulate filtering equipment, which is still experimental. Introduction of the necessary technologies is expected to result in price increases, which, in the longer term, might be absorbed. Regular inspections would be necessary to ensure that the emission standards of new vehicles were maintained in use.
1 INTRODUCTION
This report is a summary of a literature survey conducted by Ricardo Consulting Engineers plc on behalf of the Transport and Road Research Laboratory. The survey considered the impact of various levels of exhaust emission control on the design and operation of heavy duty diesel engines. The study was primarily concerned with engines for use in highway vehicles of greater than 3.5 tonne gross vehicle weight in Europe, although activities in emission control in both the USA and Japan are included largely for comparison.
The work was carried out by analysing and collating published literature and in-house data where confidentiality permitted. Areas where little or no information was located were identified and recommendations for further research into these aspects were made.
Eight major headings were identified for study. They were: --
(i) Heavy duty diesel usage: current and projected trends.
(ii) Current and proposed exhaust emission regulations and test methods.
(iii) Emissions levels selected for study.
(iv) Noise control legislation.
(v) Review of gaseous emission reduction techniques.
(vi) Review of particulate emission reduction techniques.
(vii) The impact of the seven selected emissions levels on heavy duty diesel engines.
(viii) Enforcing legislation.
The main findings under each heading are summarised below, together with a list of references to the source material used. The reference numbers are those given in the complete bibliography (Appendix A). A more detailed report of the study is contained in Vehicles and Environment.Division Working Paper VED/87/39 (Tonkin and Etheridge, 1987).
2 HEAVY DUTY USAGE- - CURRENT AND PROJECTED TRENDS
In Western Europe diesel engine production for truck applications has shown a small decrease of some 3 per cent over the period 1982-1985. Ricardo Consulting Engineers believe that the trend will reverse and a growth of about 5 per cent can be expected over the period to 1991. The truck market is mature with the use of diesels in transport applications being near 100 per cent and fluctuations in the market occuring only as a result of economic conditions.
Except for the lowest weight class vehicles there is a continuing trend to adopt turbocharging as a means of increasing specific power and reducing fuel consumption. For vehicles over 16 tonne GVVV the adoption of turbocharging is almost universal and there is an additional trend in these weight classes towards the use of charge cooling for the same reasons. The current penetration of charge cooled engines is some 40 per cent and is expected to increase.
The trend of technological development and increasing engine complexity will continue as manufacturers strive to achieve legislative requirements and maintain a competitive position. Projected trends show that engines will continue to
become lighter, more compact, more efficient and cheaper for a given power rating and emission standard. This is i l lustrated in Figure 1.
.R
¢Z
r 3 -
2 -
1 -
0 1960
I I I 1970 1980 1990 2000
Year
23o
i 20 210
~200
g 190
180 I I I 1960 1970 1980 1990 2000
Y e a r
I
x
E
.2 0
(J
. _ g ¢z
u~
4
3
2 m
1 -
o 1960
I I I 1970 1980 1990 2000
Year
0.8
3 0.6
m B 0 . 4 m
0 , 2 B
0.0 I I I 1960 1970 1980 1990
Year 2000
Fig 1 P r e d i c t e d t r e n d s in d i e s e l e n g i n e s t o y e a r 2 0 0 0 Source: Millar G H Commercial engine development t o year 2000 and beyond. SAE 840580
2
As the demand for middle distillate transportation fuels increases, fuel quality will become more variable and generally poorer. However, additives, in particular cetane improvers, will be used to prevent this aspect having a major effect on the operation of diesel engines.
[Bibliography references for Section 2: 1-15]
3 CURRENT AND PROPOSED EXHAUST EMISSION REGULATIONS AND TEST METHODS
Exhaust emission legislation in Europe is currently l imited to the control of visible black smoke (ECE Regulation 24, EEC 72/306). The adoption of ECE Regulation 49 at reduced levels to control gaseous exhaust emissions is proposed in Europe during 1988 (1 January in Austria). Draft EC directives based on ECE Regulation 49 have been prepared.
The ECE Regulation 49 test involves the measurement of oxides of nitrogen, hydrocarbons and carbon monoxide at 13 steady state operating conditions and is fundamentally similar to the procedure used in the USA up to 1985, when a transient test became mandatory. This latter test was introduced in an attempt to replicate more accurately actual city driving patterns in the USA, but it is not representative of European driving patterns. Broad empirical correlations have been drawn that allow approximate comparisons of the test methods to be made.
A progressive reduction in the allowable gaseous emission levels is planned in the USA over the period to 1994 with the additional introduction of control of particulate emissions in 1988. There are no proposals to revoke the existing visible smoke emission standard which is based on light obscuration while operating the engine over a simple transient test cycle.
Existing legislation in Japan is based on a 6 mode steady state test with different allowable levels dependant on whether the engine utilises DI or IDI combustion systems. More stringent levels are proposed for the future in Japan.
All current and proposed legislation worldwide is based on engine and not vehicle tests.
It is concluded from this section that, to achieve the required improvements in air quality, the de~/elopment of an engine test method is required that correlates with in-service emission patterns while remaining cost effective in its implementation and enforcement. It is suggested that a test based on the ECE Regulation 49 procedure with the introduction of some transient features is worthy of study. The
possible introduction of particulate standards in Europe requires further research in respect of their desirability, measurement and test methods.
[Bibliography references for Section 3: 16-21]
4 EMISSION LEVELS SELECTED FOR STUDY
Seven emission control levels of generally increasing severity were selected for study, wi th each level comprising a specified HC, NOx and smoke or particulate limit (Figure 2). Levels 1 to 3 covered current and proposed changes to European legislation whi le levels 4 to 7 covered the same theme for the USA and thus also included the introduction of particulate legislation and the use of the US transient test. In this summary levels 1, 3 and 7 are considered, covering the range discussed in the main report.
Level 1 assumes the current ECE Regulation for smoke and the ECE Regulation 49 levels for
hydrocarbons and oxides of nitrogen. Level 3 corresponds to a 20 per cent reduction in oxides of nitrogen and 30 per cent reduct ions in hydrocarbons and smoke from level 1. Level 7 corresponds to a 63 per cent reduction in oxides of nitrogen, a 50 per cent reduction in hydrocarbons and a gravimetr ical ly assessed particulate l imit of 0.1 g /bhp . (US emission levels and European emission levels are based on different test cycles, therefore these reductions can be only considered to be a guide). Levels 2, 4, 5 and 6 assume intermediate reduct ions in the rates of emission.
The selection of the seven s tudy levels was specifically aimed at consider ing the technology required to achieve var ious control standards that are either current or proposed wor ldwide. They should not be considered as proposals for int roduct ion in Europe except where any level encompasses such a proposal. The likely impact of these levels of exhaust emission control on the design, manufacture and operation of heavy du ty vehicles in Europe is considered in Section 8.
"6
Q.
JE
O .== E= .u
O. ( / )
1, F 13 -
12 -
11 -
10 -
9 -
8 "
7 "
6 •
5 •
4 •
3
2 .
1 ,
0 --
I P.M. = Particulate Mass I NO x 13.4
u
13
v
O ~ . ¢ ( N
c t - O O
o1¢~, Q.~ oJ n-n-
L U U J ~ ) ~ ) I l l i l l
HC ' 2.6
v / / L
1
NOx 10.7
I Possible adoption of a gravimetrically
assessed particulate standard I I I I I f I
N O x NO x ,0~ ,0, I I I
I I I I
* t! NOx I~ I ° I! O 7.5 E z " ~ '5 '~ '
~ ° I ° " " I ° I ° I~ NOx °
._==o ~ ... . :~ :~ I_~
-~ ~\\~ 5.0 o~ 5.0
. . . . ).6 3.6 P.M. P.M. ~.~ 7 --7 o1.
3 4 5 6 7
Assumed levels of severity
Note: Comparisons are approximate only; since different cycles and test procedures are used for the various standards
F i g . 2 R a n g e o f e x h a u s t e m i s s i o n l e v e l s s e l e c t e d f o r s t u d y
5 NOISE CONTROL LEGISLATION
Current and proposed noise control legislation was reviewed for Europe, USA and Japan. In each case a drive-by test is employed although test conditions vary. Japan currently has the most stringent legislation. In general, measures taken to control emissions, particularly timing retardation for NOx control, will also reduce noise levels. However, the technique of air/air charge cooling may increase noise whilst reducing NOx and particulate emissions. Ricardo Consulting Engineers consider that measures to reduce exhaust emissions will take precedence in future developments as alternative palliative treatments such as shielding are also available to reduce noise levels.
[Bibliography references for Section 5: 22-25]
6 REVIEW OF GASEOUS EMISSION REDUCTION TECHNIQUES
In general, the technology available to achieve reduced gaseous emission levels has changed little in recent years, but the techniques have been developed fu~her. The main developments have been carried out by component suppliers to provide equipment which encompasses the necessary technology, notable examples being the development of high pressure fuel injection equipment with
electronic control of timing and fuelling levels, variable geometry turbine turbochargers and the introduction of charge cooling. The introduction of this equipment will enable the compromises in the combustion process over the full engine speed range, which were inevitable with conventional equipment, to be significantly reduced.
6.1 NOx REDUCTION NOx formation is enhanced by an increase in combustion temperature, oxygen availability and ignition delay period.
An effective way of reducing NOx emissions is to retard the injection timing such that burning occurs later in the cycle. However, this can increase smoke and fuel consumption (Figure 3). Since NOx emissions are highest at high loads, a flexible timing plan could be introduced. This would vary the injection timing in accordance with the engine conditions to obtain a better trade off between the various pollutant levels. This type of system favours the use of electronic controls which are presently far more expensive than conventional fuel injection equipment.
Charge cooling reduces NOx emissions by reducing the charge temperature. This technique is particularly
attractive owing to the additional benefit of increased power. Typical ranges of NOx and hydrocarbon emission rates for a variety of engine types are shown in Figure 4, where it can be seen that the range of NOx emissions from turbocharged charge cooled DI engines (7-17 g/kW.h) is lower than for naturally aspirated (11-23 g/kW.h) and turbocharged (13-28 g/kW.h) DI engines.
A better trade off between NOx emissions and fuel consumption can be achieved by optimising the mixing process. The swirl level can be adjusted while rematching the combustion chamber and fuel injection characteristics. The use of higher injection pressures reduces the heat release period which allows more retarded timings to be used and leads to a better NOx/fuel consumption trade off.
Other methods of NOx reduction include chemical removal, water injection and exhaust gas recirculation. However, all of these techniques may introduce durability or logistic problems.
All currently proposed NOx levels can be achieved by use of charge cooling in combination with injection retardation and high pressure injection.
[Bibliography references for Section 6. 1: 26-35]
6.2 HYDROCARBON REDUCTION Unburnt hydrocarbons are products of the incomplete combustion of the fuel or lubricating oil. They can be controlled by the correct matching of the air/fuel mixing process and injection equipment. Detailed mechanical developments will reduce oil derived hydrocarbon levels by reducing the amount of oil entering the engine. In extreme cases major structural changes may be required. Other reductions can be made by reducing the nozzle sac/hole volume and the avoidance of secondary injections.
Diesel engines generally emit low levels of hydrocarbons, except under extreme operating conditions. Since these conditions occupy only a small portion of driving cycle time, the majority of engines can achieve all currently proposed limits with little difficulty (see Figure 4).
6.3 UNREGULATED POLLUTANT REDUCTION
Currently unregulated pollutants from diesel engines include polycyclic and nitro-polycyclic aromatic compounds (PAH and nitro-PAH), aldehydes, ketones, sulphur dioxide, hydrogen cyanide, cyanogen and ammonia.
PAH and nitro-PAH are present in a variety of forms which vary considerably in their carcinogenic and mutagenic potential. They can be reduced by decreasing the aromatic content of the fuel. Diesel engines emit significantly more aldehydes and
4
c~
A
~ v
~E ,~ ~n c
3
0 t , n
0
E
Q,.
o =
#.
A
t ' l
v
( . )
"1-
E 0 .
o
300
250
200
4
1.0
0.5
0
1.0
0.5
0
10
O O
A
Rated speed, full load
Max. torque speed, full load
15 rev/s, full load
- 0
Smoke A - - - - A - -
Particulates A
HC' A ~ A O, ~ ~O
e - I
+2 ° 0 - 2 ° Advanced Retarded
Static timing
Fig.3 Ef fect o f stat ic in jec t ion t i m i n g on pe r fo rmance
and emissions: a u t o m o t i v e t u rbocha rged DI engine
1)
3 .0
2) 3 ) -
4) 5) 6) 7 ) - -
2 . 0
o
E
g
1 . 0 - -
0 . 0 0
I
I .D.I N A %
\ %
/ / '
/ /
/ /
/ /
/ I I
t I I
~t D.I. T C A ~ \
/ /
/ /
/ /
/ /
f
/ / i
/ I / I
/ | /
! I I I I
D.I. N A
._1 10 15
(2) (1 _= (6) (5) (3) (7) (4)
i \ J \ !
i \ ' \
/ / \
/ D.I. TC / / )
I , /
2" "
/
20 25 30
Ox ides o f n i t rogen emission rate (g/kW.h)
Note : Numbers in brackets refer to levels def ined in Section 4 D.I. N A = Di rect In ject ion Natura l ly Aspirated D.I. TC = Di rect In ject ion Turbocharged D.I. T C A = Di rect In ject ion Turbocharged A f te rcoo led I.D.I N A = Ind i rect In ject ion Natura l ly Aspirated
Fig. 4 Hydrocarbon and oxides of nitrogen emissions for different engine types (European 13 mode test)
6
ketones than comparable gasoline engines. Aldehyde emissions are largely responsible for diesel odour and cause irritation of the nasal passages and eyes. The emissions are strongly related to total hydrocarbon emissions and can be controlled by the same techniques. Sulphur dioxide emissions are the result of naturally occuring sulphur in the fuel and can only be reduced by lowering the fuel sulphur content. Hydrogen cyanide, cyanogen and ammonia are present only in small quantities in diesel exhaust and are unlikely to become regulated.
[Bibliography references for Section 6.3: 36-56]
7 REVIEW OF PARTICULATE EMISSION REDUCTION TECHNIQUES
The control of exhaust particulate emissions is considered separately from gaseous emissions control
as, at present, there are no proposals for particulate controls for heavy duty engines in Europe although stringent controls are proposed in the USA.
Particulate matter arises largely from the mode of combustion used in diesel engines. This results in fuel rich zones in which carbon particles are formed. These later absorb organic compounds during the exhaust gas cooling and dilution process. These compounds include hydrocarbons, oxygenated hydrocarbons, polycyclic aromatic hydrocarbons and sulphuric acid. The hydrocarbons originating from the unburnt lubricating oil contribute signif icantly (up to 40 per cent) to heavy duty diesel particulate emissions.
Particulate emission is related to smoke and hydrocarbons although there is no direct correlation. Particulate emission is assessed gravimetrical ly while smoke is measured by a light obscuration technique.
A JE:
4-J
4-,
~L
"13
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Aromatics (per cent)
50 30 10
I I ! I 0.1 0.2 0.3 0.4 0.5
Sulphur (per cent)
Note: T90 = Temperature below which 90per cent of fuel is evaporated at atmospheric pressure
Fig. 5 Effect of fuel properties on weighted brake specific particulate emissions from a turbocharged D.I . diesel engine
Source: Wall J C and S K Hoekman. Fuel composition effects on heavy duty diesel particulate emissions. SAE 841364
1 O0
Doped fuels
Percentage Additive
o.~ o.s 1.o 2.0 3.0
(soomyl nitrate 0 (~ (~ (~ •
Aniline ./~ • • A •
Cyclohexane [ ] r;1 rn i t •
Undoped fuels
Fuel A B E F G
Key V [ ] e ~ •
E
== o
o 03
90
80
70
60
50
40
30
20
10
A
[]
131
m
Full load
! ! I I ! I I 20 30 40 50 60 70 80
Cetane number
Fig. 6 Smoke versus cetane number for a range of fuels with and without ignit ion improving additives
Source: Moul ton D S and N R Sefer. Diesel fuel quality and effects of fuel additives. Transpo~at ion Research Board, Washington DC, 1984
90
8
7.1 EFFECT OF FUEL COMPOSIT ION Fuel composition has an important effect on particulate emissions from diesel engines. The aromatic content and volatility primarily affect the carbonaceous material whereas the sulphur content determines the amount of sulphate formed (Figure 5). Fuel with a higher cetane number provides lower smoke whether of high initial quality or additive improved (Figure 6).
Studies have shown that fuel desulphurisation may be cost effective relative to other control measures, while reducing aromatic content is not considered to be a cost effective way of controlling particulate emissions.
[Bibliography references for Section 7. 1: 41, 50, 60-68, 74-80]
7.2 IN ENGINE REDUCTION T E C H N I Q U E S
High efficiency turbocharging such as variable geometry turbochargers (VGT) and charge cooling increase the air / fuel ratio and so lead to a reduction in particulate under most engine condit ions (Figure 7). Conventional turbocharging can lead to increased peak smoke levels during transient operations owing to turbocharger inertia effects. Controls which modulate the fuell ing according to the boost pressure can be fitted to engines to limit this effect.
High pressure fuel injection (Figure 8) and the use of re entrant bowl pistons are effective in reducing fuel derived particulate, largely by reducing the carbon fraction. Significant improvements can be made in smoke emission and fuel consumption by optimising
0.8
0.6
A CL J~ .Q 0.4
g_
0.2 m
0 2
Level 4
Level 6
Level 7
~ I ~ ~ / / / / B e s t conventional D.,. TC + AC ~ I
\ \ r
~ ~ Electronic timing TC + AC I
J - ~ --~ :Ss ::::: ~ It~:P °il c°ns" I
, I , I , , I 4 6 8 10 10.7
NO x (g/bhp) Fig. 7 Estimated particulates - NO x trade-off over heavy duty
transient test cycle for heavy duty diesel engines
14
12
8 x
0 z (/3
4
4
3
_~ 2
o~
1
0
220
210
"~ 200
u_
¢n 190
180
170
I I I I 030 20 10 0
I I I i 30 20 10 0
Pumping rate Low
High O - l l ~
[ ] O High + High NOP
I I I i 30 20 10 0
Start of injection (Before Top Dead Centre)
Note: ISNO x = Indicated Specific Oxides of Nitrogen ISFC = Indicated Specific Fuel Consumption NOP = Nozzle Outlet Pressure
Fig. 8 E f fec t of in ject ion rate on smoke and N O x emissions f rom a heavy d u t y d i rect inject ion diesel engine
10
the swirl ratio as a function of engine speed (Figure 9). The changes required to implement this technique in present engines would be expensive and complicated, but future engines could be developed in this way.
The reduction of the fuel and oil derived hydrocarbon fraction can be achieved by the methods discussed earlier (Section 6.1).
[Bibliography references for Section 7.2: 28, 32, 60, 70-73]
7.3 A F T E R T R E A T M E N T T E C H N I Q U E S Two general techniques, filtering and precipitation agglomeration, are available for the removal of particulates from the exhaust.
Particulate filter systems are required to trap particles within a certain size range and to oxidise them to prevent the filter system from becoming clogged. This regeneration can be achieved by two methods:
(i) The temperature of the exhaust stream can be increased periodically beyond that normally encountered. Burner systems or exhaust throttling can be used.
(ii) The regeneration temperature can be reduced by the use of catalysts. These can be in the fuel, sprayed onto the filter or permanently coated on the filter.
Precipitation agglomeration devices rely on the fact that soot particles carry a significant electrical charge and can therefore be removed by a electrostatic trap. The collected particles can be recycled to the engine or manually disposed of.
For large reductions in particulate, filtering techniques are required. However, none of the types of trap tested has yet demonstrated the durability and reliability consistent with heavy duty truck requirements.
[Bibliography references for Section 7.3: 81-108]
8 THE I M P A C T OF THE SEVEN S E L E C T E D E M I S S I O N L E V E L S ON HEAVY DUTY DIESEL ENGINES
The likely impact of the seven exhaust emission levels discussed in section 4 on the design, manufacture and operation of heavy duty vehicles in Europe is considered. In this summary only three example levels are described; the full details are given in Tonkin and Etheridge (1987).
~.Qe== Variable swirl inlet port ! O Conventional inlet port
3 -
2
o
-1
15
~ 10
N s
0 - - • " " -
I I I --5 2 3
Swirl ratio Engine speed 2200 rev/min Load 100%
A
O
03 m ~
1
0
--1
5
0
--5
v
I I 2 3
I 1 2 3
Swirl ratio Engine speed 1400 rev/min Load 100%
O
1
0
--1
--2
10
5
0
--5
--10
t I I I 2 3 4
I ! I 2 3 4
Swirl ratio Engine speed 600 rev/min Load 100%
Fig. 9 Full load performance o f a variable swirl inlet port
Source: Shimada T, K Sakai and S Kurihara. Variable swirl inlet system and its effects on diesel per- formance and emissions. SAE 861185
11
8.1 LEVEL 1 (CURRENT ECE R E G U L A T I O N 24 A N D ECE R E G U L A T I O N 49 L IMITS)
The introduction of Level 1 exhaust emission limits would pose no real'problems for the majority of heavy duty diesel engines with the possible exception of some older designs. They could easily be adjusted by retarding the injection timing to meet the NOx limit.
8.2 LEVEL 3 (20 PER CENT R E D U C T I O N FOR NOx A N D 30 PER CENT R E D U C T I O N FOR HC A N D S M O K E FROM LEVEL 1)
Level 3 emission limits would present a major technical problem to diesel engine manufacturers. Naturally aspirated engines would have to be derated to meet the smoke level. Turbocharging would generally be necessary to maintain the required rating. For turbocharged engines, one or more of the following features would have to be adopted:
(i) Rematching of the turbocharger to give increased low speed airflow using wastegating or a variable geometry turbocharger.
(ii) Remote control of the fuelling curve and a more complex timing schedule, probably using electronic control.
(iii) Increased injection pressures with suitably rematched nozzles and combustion bowl dimensions.
The reliablility and durability of these techniques have yet to be proven for production and their costs are relatively high at present.
8.3 LEVEL 7 (63 PER CENT R E D U C T I O N FOR NOx A N D 50 PER CENT R E D U C T I O N FOR HC FROM LEVEL 1, 0.1 G / B H P P A R T I C U L A T E LIMIT)
Level 7 would pose severe problems to manufacturers as the particulate limit can at present only be met by after-treatment techniques. Since the durability and reliability of the necessary equipment have yet to be proved, this level of control cannot be considered feasible at present. However, the gaseous emission levels could be achieved by incorporating the following technological features:
(i) Good base engine design with low friction
(ii) High efficiency turbocharging, probably incorporating VGT (Variable Geometery Turbocharging)
(iii) Low temperature charge cooling, possibly modulated
(iv) Well matched combustion system with re- entrant combustion chamber
(v) High pressure fuel injection with electronic control of timing and fuelling
(vi) Injectors with low sac volume or sacless nozzles with the valve covering the orifice (VCO).
(vii) Low oil consumption
Introduction of the above technologies is expected to produce an initial increase in prices. In the longer term this increase may well be masked by other economic factors, for example; the electronic systems on which the emission control technology relies are unlikely to increase in cost as rapidly as the rest of the vehicle. Improved manufacturing techniques and increased production levels may also reduce component costs but the size of the heavy duty market will limit the gains available. Many of the features identified may be introduced to improve fuel economy in markets without emission controls and will help to obviate the worsening of fuel economy that is inevitable with stringent emission performance. In the case of electronic control systems, where high levels of accuracy and reliability are required from the input transducers, costs are expected to remain significant. Other measures such as turbocompounding, advanced transmission systems and vehicle streamlining may also be introduced to assist in retaining good fuel consumption.
[Bibliography references for Section 8: 25, 27, 32, 110-113]
9 E N F O R C I N G L E G I S L A T I O N
Because of the increasing use of diesel engines and the type of pollutants they emit, stricter legislation is necessary to maintain acceptable standards of air quality. As legislative requirements become tighter, emissions control techniques tend to become more complex and doubts concerning their reliability and durability are raised. The enforcement of the emission rates of new model vehicles will not ensure that their performance is maintained during service.
There are various ways in which the emissions performance of vehicles can deteriorate, including extension of their useful life combined with the neglect of regular maintenance, incorrect or incompetent maintenance, wear of emission related components and deliberate tampering. Regular vehicle inspections would be needed to ensure that vehicles are adequately maintained and their engine controls not tampered with. It would seem appropriate that such inspections be carried out in conjunction with the annual saftey check, although the effectiveness of annual inspection is uncertain because of the high mileage accumulation rates of trucks. Emission related components should be designed to discourage tampering between inspections.
12
In-service testing of vehicles demands that the tests and their results can be related to the legislative standards to which they were manufactured. Satisfactory accuracy of smoke measurement cannot be obtained from a free acceleration test. Controlled road testing or chassis dynamometer testing is preferable. The increasing complexity of certification tests makes it very difficult to achieve the essential requirement for a correlation between these and the much simpler in-service procedures.
[Bibliography references for Section 9: 80, 122-142]
10 CONCLUSIONS
In recent years there has been a small decrease in Western European production of diesel engines for truck applications. This trend is expected to reverse. The increased application of advanced technology, particularly turbocharging and charge cooling of heavy duty engines, allows the production of lighter more compact, more efficient and cheaper units for a given power output and emission standard.
The quality of diesel fuel is expected to deteriorate but the use of additives will minimise adverse effects.
Emission legislation for commercial vehicles in Europe is currently limited to the control of visible smoke, although gaseous standards are proposed. A cost effective test method is required that correlates with in-service emission patterns.
Technologies are now available to reduce emissions from heavy duty diesel engines:
--NOx emissions can be reduced by retarding the injection timing and optimising the fuel/air mixing process. Higher injection pressures and an automated timing plan would enable this to be accomplished without increasing other emissions. Charge cooling also reduces NOx emissions.
--Hydrocarbon emissions can be reduced by suitable design of the fuel injection equipment and mechanical developments to the engine to minimize the consumption of lubricating oil.
--Unregulated pollutants can be reduced by decreasing the aromatic and sulphur content of the fuel and by techniques for reducing hydrocarbons.
--Particulate emissions can be reduced by changes in the fuel, by engine modifications and by exhaust after-treatment. Lower emissions are produced from fuel that is more volatile and has reduced aromatic and sulphur content. Beneficial engine modifications include high efficiency turbocharging, charge cooling, high pressure fuel injection and improvements to the air/fuel mixing process. Two categories of exhaust
treatment device can be used: precipitation agglomerators or particulate filters. Filters require auxiliary equipment or a catalyst to oxidise the trapped particles.
All current heavy duty diesel engines can meet both present and proposed European standards for gaseous emissions with little or no adjustment. To achieve further reduction in smoke or particulate, whilst also reducing gaseous emissions; it would be necessary to incorporate technically feasible, but unproven technologies. These would presently impose a significant cost penalty. The most severe emission level considered in this study would pose considerable problems to engine manufacturers. Current technologies cannot achieve the particulate reduction required while retaining the durability and reliability needed for heavy duty operation.
Regular vehicle inspections would be necessary to ensure that in-service emissions are kept within acceptable limits. In-service tests and results must relate to the legislative standards to which the vehicles were manufactured. However, because of the possible complexity of certification tests and the requirement for simple in-service procedures, such a correlation could be very difficult.
11 REFERENCE
TONKIN P R and ETHERIDGE P 1987. A new study of the feasibility and possible impact of reduced emission levels from diesel engined vehicles. Working Paper VED/87/39: Transport and Road Research Laboratory, Crowthorne. (Unpublished paper available on direct personal application only)
12 A C K N O W L E D G E M E N T
The work described in this report was carried out by Ricardo Consulting Engineers plc under contract to the Vehicles and Environment Division of the Vehicles Group of TRRL.
A P P E N D I X A B I B L I O G R A P H Y
The following reference list does not contain all the information normally included in a TRRL RR. Information was limited to the original contractors report on which this listing is based.
1. PRS Autodata 1980-1985 Planning Research and Systems PLC 44-48 Dover St London W l X 3RF tel: 01-409-1635
(This is a database, not a citation)
13
2. World trends in vehicular diesel production Schultz, R High speed diesel report, 1986 May/June
pp20, 22, 24 ISSN: 0730-5303 Publisher: Diesel and Gas Turbine Publications
13555 Bishop's Court Brookfield WI 53005 USA
3. Automotive news work outlook Data Resources Inc In Automotive News, 1986 May 26 p50 (ISSN 0005-1551 ) Publisher: Automotive News
1400 Woodbridge Detroit Michigan MI 48207 USA
4. The future of the world motor industry Krish Bhaskar Nichols Publishing Company 1980
5. World motor vehicles Predicasts Inc. May 1978.
6. World motor vehicle data Chase Econometrics 1981 Edition.
Refs 4 -6 Extracted from: World motor vehicle demand
Westenberg Schaeffer
US Dept of Transportation
August 1982
7. Fuels challenges and opportunities Paramins Fuels Additives Seminar 1985/86 29 October 1985. Paramins European Demand Forecast Paramins Fuel Seminar 85/86
8. Energy policies and programmes of lEA countries 1984 review
Paris: Organisation for Economic Cooperation and Development, 1986
ISBN: 92-64-12783-6
9. Transport statistics Great Britian 1975-1985 Department of Transport (HMSO Sept 1986, 213pp)
10. Sawer J M, A review of diesel engine emissions in Europe (Ricardo DP 86/1946 Restricted)
11. Millar G H, Commercial engine development to year 2000
and beyond. (SAE 840577)
12. Bernstein L S European automotive Fuels for the.80's and 90's (SAE 845047)
13. Trends in future automotive fuels on the German market
Dabelstein, WEA and Reglitzky, AA Groupement Francais de Coordination, European
Automotive Fuels and Lubricants Symposium, 3-4 October, 1984, Neuilly, France
14. Technology Interchange in fuels and lubricants (Automotive Engineer Jun/Jul 1986, pp 52-55)
15. Diesel fuel--European quality survey Ethyl Corporation (Brussels, Belgium, Ethyl Corporation, Survey
No 3, Winter 1983) (Ethyl Symposium, Geneva, February 1984,
Survey No 4, Winter 1984-5)
16. The Council of the European Communities. Proposal for a council directive 9037/86 Add 1, Rev 2. Brussels 10.11.86
17. United Nations Agreement concerning the adoption of Regulation No 49 (May 10, 1983) Intereurope.
18. US Code of Federal Regulations. Volume 40 Parts 81-99. Revised as of July 1, 1986.
19. Osenga M Business Notes (Diesel Progress North American, March 1987,
p48)
20. Japanese Ministry of Transport. Prevention of emission of smoke, bad smelling
and harmful gases (Sept. 1975) Intereurope.
21. Japanese Ministry of Transport MOT News. Target values for truck and bus NOx emissions
reduction, 21 July 1986.
22. Commission directive 70/157/EEC. The permissible sound level and the exhaust
system of motor vehicles. Official Journal of the European Communities,
23 Feb 1970.
23. Transportation equipment noise emissions controls--medium and heavy trucks.
Federal Register Vol 41 No 72, 13 April 1976.
24. Japan Ministry of Transport. Automobile Type Approval Test Division. 'Partial revision of noise test procedure for road
vehicles'. TRIAS 20-1980.
14
25. Winsor R E, VanderBok A J, Hammer W G, The new DEDEC series 60 diesel engine. SAE 870616.
26. Nightingale, D R, A fundamental investigation into the problem of
NO formation in diesel engines (SAE 750849)
27. Schwartz, R, Robert Bosch High pressure injection pumps with electronic
control for heavy duty diesel engines (SAE 850170)
28. Shimada T, Sakai K, and Kurihara S, Mitsubishi Motors Variable swirl inlet system and its effect on
diesel performance and emissions (SAE 861185)
29. Truck engine for the 1990's Needham, J R and Sandford, M H Paper presented at the Energy Sources
Technology Conference and Exhibition, 15-20 February, 1987, Dallas, Texas USA
ISSN: 0402-1215
30. High BMEP diesel engine with variable geometry turbocharging and turbochargers
Yokota, K, Shimizu, M, Furukawa, H, Hattori, H Third International Conference on Turbocharging
and Turbochargers, 6-8 May, London, 1986 ISSN: 0144-0799
31. Ishida A, Kanamoto T, and Kurihara S, Mitsubishi Improvements of exhaust gas emissions and cold
startability of heavy duty diesel engine by new injection-rate control pump
(SAE 861236)
32. Cartellieri W P, and Wachter W F, Status report on a preliminary survey of
strategies to meet US-1991 HD diesel emission standards without exhaust gas aftertreatment
(SAE 870342)
33. Cadnam W, and Johnson J H, The study of the effect of exhaust gas
recirculation on engine wear in a heavy-duty diesel engine using analytical ferrography
(SAE 860378)
34. Gladden J R, Ammonia/fuel ratio control system for reducing
nitrogen oxide emissions (International Patent Application No. PCT/US81/00845 Published 6 January 1983)
-35. Perry R A, and Siebers D L, Rapid reduction of nitrogen oxides in exhaust
gas streams (Nature; 18-25 December 1986, pp 657-658)
36. Particulate polycyclic organic matter National Academy of Science (Published; Washington DC 1972)
37. Dipple A, Chemical carcinogens ACS Monograph 173 (Published; American Chemical Society
Washington DC 1976 pp 245)
38. Kotin P, Falk H L, and Thomas M, Aromatic hydrocarbons III prescence in the
particulate phase of diesel engine exhausts in the carcinogencity of exhaust extracts (American Medical Association, Arch. Ind. Health, 1955, Vol II, pp 113-120)
39. Kotin P, Falk H L, and Thomas M, Aromatic hydrocarbons AMA Arch. Ind. Health Vol. 9 pp 164 (1954)
40. Mills G A, Howarth J S, and Howard A G, The effect of diesel fuel aromaticity on
polynuclear aromatic hydrocarbon exhaust emissions
(Journal of the Institute of Energy, March 1985 pp 273-286)
41. Barry E G, McCabe L J, Gerke D H, and Perez J M,
Mobil; Caterpillar Tractor Heavy-Duty diesel engine/fuels combustion
performance and emissions--a cooperative research program
(SAE 852078)
42. Shore P R, Alternative fuel effects on diesel engine PAH
and nitro-PAH emissions (Ricardo DP86/1687; Unrestricted)
43. Shore P R, Alternative fuel effects and diesel particulate
compostition. (Ricardo DP85/1159; Restricted)
44. Schuetzle, D, and Perez, J M, Factors influencing the emissions of nitrated-
polynuclear aromatic hydrocarbons (Nitro- PAH) from diesel engines
(J. Air Pollution Control Assoc. 33 (1983) 751-755)
45. Gaddo, P, Settis, M and Giacomelli, L Artifact formation during diesel particulate
Collection (Paper presented at 8th Symposium on
Polynuclear Aromatic Hydrocarbons, October 1983, Battelle, Columbus, OH.)
15
46. Pitts, J N Jr, Van Cauwenberghe, K A Grosjean, D, Schmid, J P, Fitz, D R, Belser, W L Jr, Knudson, G B and Hynds, P M,
Atmospheric reactions of polycyclic aromatic hydrocarbons: facile formation of mutagenic nitro derivatives
(Science 202 (1978) 515-519)
47. Risby, T H and Lestz, S S Is the direct mutagenic activity of diesel
particulate matter a sampling artifact? (Environ. Sci. Technol. 17 (1983) 621-624)
48. Springer K J, and Baines T M, Emissions from diesel versions of production
passenger cars (SAE 770818)
49. Mogan J P, Dainty E D, Vergeer H C, Lawson A, Westaway K C, Weglo J K, and Thomas L R,
Investigation of the CTO emission control system applied to heavy duty diesel engines used in underground mining equipment
(SAE 850151 )
50. Environmental Protection Agency 40 CFR PART 86
(AMS-FRL-2947-50) Standards for emissions from methanol-fuelled motor vehicles and motor vehicles engines
EPA (Federal Register, Aug. 1986. Vol. 51 No. 168;
pp 30984-30998)
51. International agency for research on cancer formaldehyde
in: monographs on the evaluation of the carcinogenic risk of chemicals to humans, no 29 pp 345-389
Lyon: International Agency on Research on Cancer, 1982
ISBN: 92-832-1529-X
52. Lesley S L, and French C C J, Diesel exhaust and odour (SAE 760554)
53. Cernansky N P, Diesel exhaust odour and irritants--A review (Journal of the Air Pollution Control Association
Vol. 33 No. 2, 1983 pp 97-104)
54. Cernansky N P and Petrow E D, A comparison of the odourous emission from a
direct injection and indirect injection diesel engine
(International Journal of Vehicle Design, March 1985 pp 183-198)
55. Council directive of 15th July 1980 on air quality limits values and guide values for sulphur dioxide and suspended particles.
Official Journal of the European Communities 30 August 1980. (I ?~9/30-1 :)99/48)
56. Derwent R G, and Hough A M, Ozone precursor relationship's in the United
Kingdom (Harwell, Oxfordshire, AERER 12408 Dec 1986,
HL86/1471 [C10] p71)
57. Norris-Jones S R, Hollis T, and Waterhouse C N F ,
A study of the formation of particulates in the cylinder of a direct injection diesel engine
(SAE 840419)
58. Cuthbertson R D, Stinton, H C, and Wheeler R W,
The use of a thermogravimetric analyser for the investigation of particulates and hydrocarbons in diesel engine exhaust
(SAE 790814)
59. Cuthbertson R C, Shore P R, Sundstr6m L and Heden P-O,
Direct analysis of diesel particulate-bound hydrocarbons by gas chromatography with solid sample injection.
(SAE 870626)
60. Wall J C, and Hoekman S K, Chevron Research Fuel composition effects on heavy duty diesel
particulate emissions (SAE 841364)
61. Sawer J M, Final summary report of the European Future
Diesel Fuels Consortium Programme (Ricardo DP86/1103 Restricted)
62. Environmental Protection Agency 40 CFR Parts 79, 80 and 86 (AMS-FRL-3038-8) Diesel fuel quality effects on
emissions, durability, performance and costs; Availability of a draft study. (Federal Register June 1986 Vol 51, No 124,
pp 23437.
63. British Standard 2869:1983 Specification for fuel oils for oil engines and
burners for non-marine use.
64. Draft minutes of the Diesel Engine Technical Committee Meeting held on 12 November 1986.
(SMMT DE/86/38)
65. Ingham M C, Warden R B, Cost-effectiveness of diesel fuel modifications for
particulate control (SAE 870556)
16
66. Tennyson T A, and Parker C K, Locomotive radioactive ring studies of fuel,
lubricant and operating variables. (SAE 700892)
67. Weaver C S, Miller C, Johnson W A, and Higgins T S,
Reducing the sulphur and aromatic content of diesel fuels--costs, benefits and effectiveness for emissions control.
(SAE 860622)
68. Annual Report 1985 CONCAWE (The Hague, Netherlands; CONCAWE, February
1986, Report 1/86, pp12)
69. Callahan T J, Ryan T W, Dietzmann H, and Waytulons R,
The effects of discrete transients in speed and load on diesel engine exhaust emissions
(SAE 850109)
70. Kamimoto T, Aoyagi Y, Matsu T, and Matsuoka S,
The effect on some engine variables on measured rates of air entrainment and heat release in a DI diesel engine.
(SAE 800253)
71. Wade W R, Hunter C E, Trinker F N, and Hansen S P,
Future diesel and engine combustion systems for low emissions and high fuel economy
(SAE 865012)
72 lida N, Suzuki Y, Takeshi Saito G, and Sawanda T,
Effects of intake oxygen concentration on the characteristics of particulate emissions from a DI diesel engine.
(SAE 861233)
73. Takeshi Saito G, Daisho Y, Uchida N, Ikeya N, Effects of combustion chamber geometry on
diesel combustion (SAE 861186)
74. UIIman T L, Hare C T, and Baines T M, Emissions from two methanol-powered buses (SAE 860305)
75. Weaver C S, Klausmeier R J, Erickson L M, Gallagher J , and Hollman E ,
Feasibility of retrofit technologies for diesel emissions control
(SAE 860296)
76. UIIman T L, and Hare C T, Emissions from direct injection heavy duty
methanol-fuelled engines (one dual-injection and one spark ignited) and a comparable diesel engine
(SAE 820966)
77. Lencero T S, Valderrama F, and Munoz A, Alcohols as diesel fuels (Symposium on Combustion in Heat Engines,
Polytechnic University of Madrid 20-22 March 1985; Paper 7, 22 pp)
78. Moulton D S, and Sefer N R, Diesel fuel quality and effects of fuel additives,
Transportation Research Board (Published: Washington DC May 1984 70 pp)
79. Apostolescu N D, Matthew R D, and Sawyer R F,
Effects of a barium-based fuel additive on particulate emissions from diesel engines
(SAE 770828)
80. Collins D, Cuthbertson R D, Gawen R W, and Wheeler R W,
The use of a constant volume sampler and dilution tunnel to compare the total particulates from a range of Automotive Engines.
(SAE 750904)
81. Abthoff J, Schuster H D, Langer H J, and Loose G,
The regenerable trap oxidizer--an emission control technique for diesel engines
(SAE 850015)
82. Takama K, Kobashi K, Oishi K, Inoue T, and Kogiso T,
Regeneration process of ceramic foam diesel-- particulate traps
(SAE 841394)
83. Sachder R, Wong V W, and Shahed S M, Analysis of regeneration data for a cellular
ceramic particulate trap (SAE 840076)
84. Howitt J S, Particulate control technology for light and
heavy duty diesel powered vehicles. (Forum International sur les Nouvelles
Technologies Automobiles, Monte Carlo, 29 Jan-2 Feb 1985, AT85037, pp 207-219
85. Gulati S T Strength and thermal shock resistance of
segmented wall-flow diesel filters (SAE 860008)
86. Hardenberg H O, Daudel H L, Erdmannsdorfer H J,
Experiences in the development of ceramic fiber coil particulate traps
(SAE 870015)
87. Gulati T S, and Merry R P, Design considerations for mounting material for
ceramic wall-flow diesel filters (SAE 840074)
17
88. Hardenberg H O, Urban bus application of a ceramic fiber coil
particulate trap (SAE 870011 )
89. Hardenburg H O, Daudel H L, Edmannsdorfer H J,
Catalytic control of diesel particulate (SAE 870016)
90. Enga B E, Buchman M F, and Lichtenstein I E, Catalytic control of diesel particulate (SAE 820184)
91. Enga B E, Plakash J F, Budd A E R, and Jaffray C,
The evaluation of catalyst particulate control on buses
(SAE 850146)
92. Rijkeboer R C, van Ling J A N and van der Weide J,
The catalytic trap oxidiser on a city bus: a Dutch demonstration program
(SAE 860134)
93. Hickman A H, Jaffray C, Performance and durability of a catalyst trap
oxidiser installed in a city bus for 65000 miles of revenue service.
(SAE 860138)
94. Danis A M, Partridge P A, and Cernansky N P, Effect of ceramic monalith particulate filters on
diesel exhaust odourant and irritant species (SAE 850011 )
95. Westerholm R, Alsberg T, Strandell M, FromeUin A, Grigoriadis V, Hantzaridou A, Maitra G, Winquist L, Rannug U, Egeback K- E, and Bertilsson T,
Chemical analysis and biological testing of emissions from a heavy-duty diesel truck with and without two different particulate traps
(SAE 860014)
96. Watabe Y, Irako K, Miyajima T, Yoshimoto T and Murakami Y,
'Trapless" trap--a catalytic combustion system of diesel particles using ceramic foam
(SAE 830082)
97. Kiyota Y, .'l'suji K, Kume S, and Nakayama O, Development of diesel particulate trap oxidiser
system (SAE 860294)
98. Environmental Protection Agency Request for proposals Engineering of diesel particulate trap
regeneration control strategies (EPA. RFP Doc. C186-A812, January 1987)
18
99. Polach W, and Hagele K-H, Initial results of the use of an electrostatic soot
separator on an automotive diesel engine (SAE 845080)
100. Kittelson D B, Pui D Y H, and Moon K C, Electrostatic collection of diesel particles (SAE 860009)
101. Arai M, Mujashita S, and Sato K, Development and selection of diesel particulate
regeneration system (SAE 870012)
102. Pattas K M, Stamatellos A M, Patsatzis N A, Kikidis P S, Aidarinis J K, and Samaras Z C,
Forced regeneration by exhaust gas throttling of the ceramic diesel particulate trap
(SAE 860293)
103. Niura Y, Ohkubo K, and Yagi K, Study on catalytic regeneration of ceramic
diesel particulate filter (SAE 860290)
104. Lawson A, Vergeer H C, Drummond W, Mogan J P, and Dainty E D,
Performance of a ceramic diesel particulate trap over typical mining duty cycles using fuel additives
(SAE 850150)
105. RaoVD, WhiteJ E, WadeWR, Aimone M G, and Cikanek H A,
Advanced techniques for thermal and catalytic diesel particle trap regeneration
(SAE 850014)
106. Environmental Protection Agency Test procedure issues for trap-based particulate
standards and the use of fuel additives for particulate trap regeneration systems. Staff analysis paper ECTD/SDSB
(EPA Workshop, Vehicle Emissions Laboratory, 4th Paper Attachment IV July 1985, p21)
107. Dainty E D, Lawson A, Vergeer H C, Manicom B, Kreuzer T P, and Engler B H,
Diesel emissions reduction by ceramic filters employing catalysts or a fuel additive
(SAE 870014)
108. McCabe R W, and Sinkevitch R M, Oxidation of diesel particulates by catalysed
wall-flow monolith filters (SAE 870009)
109. Committee of Common Market Automobile Constructors
Diesel commercial vehicle emissions--evolution of regulations (Society of Motor Manufacturers and Traders TEC/943/1985. Annex II, September 1985)
Restricted to members only
110. Blakemore T Detroit chips in with an overhead camshaft six (Commercial Motor, 14 March 1987, p 23)
111. Environmental Protection Agency 40 CFR Parts 86 and 600
Control of Air Pollution from new motor vehicles and new motor vehicle engines; Gaseous emissions and particulate emission regulations
(Federal Register March 1985 Vol. 50, No 51 pp 10630)
112. Rajan J, Singh M K, and Moses D O, Analysis of the costs of particulate trap-oxidiser
systems for heavy-duty diesel vehicles. (Argonne National Laboratories, Illinois, USA,
1986 CONF--860606-16, DE86014496/WEP, 17 pp)
113. Transport Engineer, January 1987.
114. Huisingh J L, Bradow R, Jungers R, Claxton L D, Zweidinger R, Tejada S, Bumgarner J, Duffield F, Waters M, Simmon V F, Hare C, Rodrigues C, and Snow L,
Application of short-term bioassays in the fractionation and analysis of complex environmental mixtures
Waters et al (Eds), pp 1-32 U.S. Environmental Protection Agency EPA-600/9-78-027, (1978)
115. Broome M G, What the bugs can't tell us Arthur G Little (Presented at CRC Chemical Characterisation of
Diesel Exhaust Emissions) Workshop II, 4-6 March 1985, Dearborn (unpublished)
116. Shore P R, Tesh J M, and Bootman J, Application of short-term bioassays to the
assessment of engine exhaust emissions (SAE 870627)
117. Ball, D, Black lungs and black walls (New Scientist: 12 February 1987 p 28)
118. Diesel may fuel London's bladder cancers New Scientist 23.1.86 pp 24.
119. Brightwell J, Fouillet X, Cassano-Zoppi A L, Gatz R, Duchosal F,
Neoplastic and functional changes in rodents after chronic inhalation of engine exhaust emissions
Developments in Toxicology and Environmental Science, 1986 13 pp 471-485
ISSN: 0165-2214
120. Monaghan M L, Comments on TNO report R86/038. (Ricardo DP 86/1485, Restricted)
121. Van Der Hout K D, Rijkeboer R C, Diesel exhaust and air pollution (Delft, The Netherlands, 23 January 1986,
TNO Report R86/038, 34 pp)
122. Holman C, Air pollution from diesel vehicles--A Friends of
the Earth report (Friends of the Earth, Feb, 1987, 33 pp)
123 Goldstein E A, and Paly M, The diesel problem in New York city (Natural Resources Defense Council, New York
April 1985, 48 pp)
124. State of California Air Resources Board Reasonable efforts program Proposed emission reduction goals for motor
vehicles. Sept 1985.
125. Black F, Braddock J, Bradow R, and Ingalls M, Highway motor vehicles as sources Of
atmospheric particles: projected trends 1977 to 2000
(Environmental International, Vol II, pp 205-233, 1985)
126. Transport statistics Great Britian 1975-1985 Department of Transport (HMSO, Sept 1986, 213 pp)
127. Weaver C S, and Klausmeir R F, Inspection and maintenance for heavy-duty
diesel vehicles Part 1 - Evaluating the Need. (SAE 861546)
128. Hames R J, Straub R D, and Amann R W, DDEC Detroit Diesel Electronic Control (SAE 850542)
129. Moncelle M E, and Fortune G C, Caterpillar 3406 PEEC (Programmable Electronic
Engine Control) (SAE 850173)
130. Klausmeier R, Gallagher J, Barrett R and Holman E,
The Colorado Diesel Emissions Control Program-- Stage 1.
(SAE 850149)
131. Austin T C, and Hussan L, Design and Enforcement of I /M programs for
maximum effectiveness (SAE 852108)
132. Potter C J, Savage C A, and Simmonds A C, The development and validation of an on-board
diesel particulates sampler. (Warren Spring Laboratory, Report LR 549
(AP)M IS B N 0 85624 404X
19
133. Alkidas A C, Relationships between smoke measurements
and particulate measurements. (SAE 840412)
134. Vuk T C, Jones A M, and Johnson J H, The measurement and analysis of the physical
character of diesel particulate emissions. (SAE 760131)
135. Armitage A, Report of the Inquiry into lorries, people and
the environment. (HMSO, 1980)
136. Royal Commission on Environmental Pollution Tenth Report, Chairman--Sir Richard
Southwood. Tackling pollution--experience and prospects. (HMSO, 1984)
137. Pitman R J, A practical method of measuring the smoke
emission of diesel engined vehicles in service. (I Mech E, C370/80, 1980)
138. Progress Report to ISO/TC22/SC5 On the Work of WGI--Opacimeters. April 1974.
Work carried out under 'Road vehicles--lug down test for measurement of opacity of exhaust gas from diesel engined vehicles'
Draft ISO Proposal DP7644 (ISO/TC22/SC5 N439)
139. Pitman R J, A practical method of measuring the smoke
emission of diesel engined vehicles in service. (I Mech E, C370/80, 1980)
140. Italian standpoint on alternatives to the free acceleration mode for spot road inspections of diesel-engined vehicles.
(Submission to 3rd Meeting of BPICA GEPE, Paris, January 1980)
141. National Swedish Environment Protection Board Working Group 179/4
The measurement of diesel exhaust smoke on vehicles in service.
(Swedish Institute of Mechanical Engineers, 22 September 1984, 71 pp)
142. CEC CF-11 Status report of test programme on particulate
emissions measurement transmitted by CEC CF-11 working group.
(Co-ordinating European Council CF-11, 31 October 1985, VE/CEC/1, 28 pp)
143. Danielson E R, Draft recommended practice for measurement
of gaseous and particulate emissions from heavy duty diesel engines under transient conditions.
(EPA SD1SB-79118, 1979)
144. Springer K J, and Stahman R C, Removal of exhaust particulates from a
Mercedes 300D Diesel car (SAE 770716)
145. Lipkea W H, Johnson H J, and Vuk C T, The physical and chemical character of diesel
particulate emissions. Measurement Techniques and Fundamental Considerations.
(SAE 780108)
146. Murphy M J, Hillenbrand L J, and Trayser D A, Assessment of diesel particulate control: direct
and catalytic oxidation. (EPA 600/7-79-2326, 1979)
147. Frey J W and Corn M, Physical and chemical characteristics of
particulates in diesel exhaust. (American Industrial Hygiene Association
Journal, September-- October 1967)
Printed in the United Kingdom for Her Majesty's Stationery Office (2677188) Dd8222739 11188 03 C426 10170
20