Effects on Particulate Emissions And

PARTICULATES

Characterisation of Exhaust Particulate
Emissions from Road Vehicles

Deliverable 14:

Effects on particulate emissions and

relevance of fuel quality for emission factors

Version 2 – 09/2003

A project sponsored by:

EUROPEAN COMMISSION

Directorate General Transport and Environment

In the framework of:

Fifth Framework Programme

Competitive and Sustainable Growth

Sustainable Mobility and Intermodality

Contractors

LAT/AUTh:AristotleUniversity of Thessaloniki, Laboratory of Applied Thermodynamics - EL

CONCAWE:CONCAWE, the oil companies' European organisation for environment, health and safety - B

VOLVO:AB Volvo - S

AVL: AVL List GmbH - A

EMPA: Swiss Federal Laboratories for Material Testing and Research - CH

MTC: MTC AB - S

TUT: TampereUniversity of Technology - FIN

TUG: Institute for Internal Combustion Engines and Thermodynamics, Tech.UniversityGraz - A

IFP: Institut Français du Pétrole - F

AEAT: AEA Technology plc - UK

JRC: European Commission – Joint Research Centre - NL

REGIENOV: REGIENOV - RENAULT Recherche Innovation - F

INRETS:Institut National de Recherche sur les Transports et leur Securité - F

DEKATI: DEKATI Oy - FIN

SU:Department of Analytical Chemistry, StockholmUniversity - S

DHEUAMS: Department of Hygiene and Epidemiology, University of AthensMedicalSchool -
EL

INERIS:Institut National de l’ Environment Industriel et des Risques - F

LWA:Les White Associates - UK

TRL:Transport Research Laboratory - UK

VKA:Institute for Internal Combustion Engines, AachenUniversity of Technology – D

VTTVTT ENERGY – Engine Technology and Energy in Transportation - FI

A project sponsored by:

EUROPEAN COMMISSION

Directorate General Transport and Environment

In the framework of:

Fifth Framework Programme

Competitive and Sustainable Growth

Sustainable Mobility and Intermodality

Publication data form

1. Framework Programme
European Commission – DG TrEn, 5th Framework Programme
Competitive and Sustainable Growth
Sustainable Mobility and Intermodality / 2. Contract No
2000-RD.11091
3. Project Title
Characterisation of Exhaust Particulate Emissions from Road Vehicles
(PARTICULATES) / 4. Coordinator
LAT/AUTh
5. Deliverable Title
Effects on particulate emissions and relevant emission factors
of fuel quality / 6. Deliverable No
14
7. Deliverable Responsible
CONCAWE/MTC / 8. Language
English / 9. Publication Date
{September 2003}
10. Author(s)
D Hall, N Thompson
With contributions from AVL, Volvo, TUG, VTT, LAT, Shell, AVL-MTC (IFP data not yet included in the data-base) / 11. Affiliation
CONCAWE….
12. Summary
{See report summary}.
13. Notes
{Version Notes}.
14. Internet reference
{
15. Key Words / 16. Distribution statement
FREE
17. No of Pages / 18. Price
FREE / 19. Declassification date
{DATE} / 20. Bibliography
NO

Table of Contents......

1.Summary......

2.Introduction / Objectives of “Particulates”......

3.Test fuels......

3.1.Background......

3.2.Fuel Matrices......

3.3.Lubricant Selection......

4.Engines, vehicles and after treatment technologies tested......

4.1.Overall programme plan......

5.Drive cycles and test conditions......

6.Test Results and Discussion......

6.1.General......

6.2.Heavy Duty Diesel......

6.3.Light Duty Diesel......

6.4.Gasoline......

7.Conclusions......

8.References......

1.Summary

The Particulates programme (part of the ARTEMIS cluster) aimed to improve understanding of particulate emissions and to provide input to ARTEMIS on representative particulate emissions factors for road vehicles and fuels. A harmonised exhaust particulate sampling and testing protocol was developed which has been used to evaluate particulate emissions from a range of engine and vehicle technologies, exhaust after-treatment technologies and fuels. This protocol was designed to measure solid, dry carbonaceous particles (dry branch) as well as the total particle stream (wet branch) which included volatile, nucleation mode particles.

This Deliverable discusses fuel effects on particulate emissions, based on results from tests carried out by those partners who tested more than one fuel. Effects are considered for both light duty and heavy duty vehicles. Fuel quality effects are described in context with effects of different vehicle technologies and operating conditions.

The data provide a basis for future development of emissions factors for particulate mass and if required, size/number of “solid” particles. The significant progress being made through the introduction of advanced vehicle technologies and sulphur-free fuels is clear.

Application of emissions factors to particulate size and number is complex, especially for the volatile nucleation mode, which is highly influenced by ambient variability, set-up and conditioning of equipment. Reduction of fuel sulphur content helps reduce nucleation mode particles, but the nature and formation mechanisms of these particles requires further understanding before meaningful emissions factors could be generated. More research is needed on the atmospheric fate and health effects relating to particles, especially those in the nucleation mode.

2.Introduction / Objectives of “Particulates”

Health effects of particulate emissions from road transport have been of interest for many years. To date, particulate emissions from vehicles have been controlled via legislation based on particulate mass. Recent studies have however suggested that adverse health effects may not only be dependent on total particulate mass, but on other metrics including size, number and surface area. Smaller particles have been claimed by some to cause more adverse effects than large particles. This has led to revision of the particulates Air Quality Standard in the U.S.A to include measurement of finer particulates (PM10 PM2.5) and to further evaluation of the best metric for air quality standards worldwide. In Europe, further tightening of controls on particulate emissions from vehicles is being effected through the Euro-3 and Euro-4 standards for light duty vehicles and Euro-3, 4, and 5 standards for heavy duty vehicles [1,2].

Alongside the reduction in particulate mass emissions from vehicles, measurement methodologies are being enhanced to improve the accuracy of the measurement at these very low emissions levels. Additionally, there has been a focus on the development of methodologies to measure the size and number of particulate emissions as well as mass. It is now generally accepted that automotive particle emissions fall into two broad categories:

“Accumulation” mode particles, mainly carbonaceous in nature and greater than ca. 30 nm in particle size
“Nucleation” mode particles, generally below 30 nm particle size, comprising predominantly condensed volatile material, mainly sulphate and heavy hydrocarbons

The presence of nucleation mode particles has been related to the concentration of carbon and hydrocarbons in the exhaust. Under conditions where carbon emission is reduced, there is a greater tendency to produce nucleation mode particles. The extent of this formation has been shown to be dependent on engine and fuel technology, the use of after-treatment, operating conditions and also strongly linked with sampling and measurement conditions [3].

The “Particulates” project was established to develop further knowledge on particulate emissions from motor vehicles, especially in terms of characterisation of particulate size and number emissions with current and future vehicles and fuels. It was set-up as part of the ARTEMIS project cluster [4] which aimed to update emissions factors for regulated pollutants from road transport. The main aims of “Particulates” were :

to increase knowledge and understanding of particulate emissions from motor vehicles,
to provide a harmonised particulate sampling and measurement methodology,
to provide input on representative emissions factors for particulates to enhance air quality modelling tools and help explain health effects,
to assess the effectiveness of technical measures for reducing particulate emissions.

A critical first step in the Particulates programme was the definition of the exhaust aerosol properties to be examined and the identification of suitable instruments and measurement techniques to be used. A major decision of the consortium was to tackle the difficult challenge to measure both accumulation mode and nucleation mode particles, under transient as well as steady state conditions. The nucleation mode particles presented a major challenge as they were known to be highly sensitive to test conditions.

A review of the available instrumentation and sampling techniques was carried out and reported in Deliverable 2 [5]. A harmonised sampling and testing methodology for the measurement of automotive particulate emissions, including measurement over transient test cycles, was then developed and documented in Deliverable 3 [6].

After initial assessment and roll-out of the methodology through a round robin exercise [7], a number of partners took part in adetailed measurement campaign, where the developed protocol was applied to study particulate emissions from current and near future vehicle technologies and fuels. This represented the time that such a comprehensive harmonised particulate sampling and measurement protocol (mass, size, number, surface area) had been run in multiple laboratories. This Deliverable describes the results obtained regarding fuel effects on particulate emissions, based on the results from those partners which tested more than one fuel.

3.Test fuels

3.1.Background

The core test fuels were selected based on the objectives to develop input on representative emissions factors for current and future vehicle fleets as well as to enhance understanding of fuel effects. Existing knowledge indicated fuel sulphur as a key fuel effect on particle emissions, both in terms of enabling new exhaust after-treatment technology and as a direct effect on sulphate emissions.

In view of the importance of fuel sulphur in enabling advanced exhaust after-treatment systems, the recent update to the EU Fuels Directive [8] requires 50 mg/kg max sulphur content in both gasoline and diesel fuels from 2005, with “appropriate geographic availability” of sulphur-free fuels (10 mg/kg max sulphur content) from the same date, progressing to 100% coverage of sulphur free fuels by 2009 (this date being subject to a further review for diesel). No other fuel property changes are required for 2005, except for the already agreed reduction in gasoline aromatics to 35% max.

3.2.Fuel Matrices

In view of the above, the test fuels were mainly designed around the sulphur effect, using base fuels with other properties held as close as possible to average year 2000/05 levels, but with as low a sulphur content as possible. Sulphur levels were adjusted to typical current, 2005 and 2009 levels by doping with sulphur compounds, thiophene and di-tertiarybutyl-di-sulphide. The target levels for the base fuel properties were derived from work on the development of reference fuel specifications for 2005 and beyond, and should therefore provide a firm basis for the development of emissions factors.

For diesel fuel, an additional sulphur-free fuel, Swedish Class 1, was also included, in order to demonstrate any further potential benefits from extreme changes to other fuel properties. Two additional diesel fuels, one at the current (year 2000) sulphur level but with higher density and aromatics content and the second, a 5% RME blend were also included in the tests by CONCAWE and AVL. A 1500 mg/kg sulphur (pre-1996 EN 590) diesel fuel was also included in the Volvo tests to estimate the previous air quality impact of older heavy duty diesel engines which operated on such fuel.

Tables 1 and 2 show the analysis data for the gasoline and diesel fuels described above.

Table 1Diesel Fuel Analyses

Fuel Code / D-1 to D-4 / D-5 / D6 / D7
Diesel Fuel Description / Units / Sulphur Matrix / Swedish
Class 1 / pre-2000 / 5% RME Blend
Characteristic / Result / Result / Result / Result
Cetane Number / 54.0 / 55.1 / 46.5 / 54.5
Cetane Index / 51.1 / 51.7 / 46.7 / 50.6
Density / kg/m3 / 845 / 810 / 856 / 846
T50 / °C / 282 / 226 / 279 / 284
T95 / °C / 358 / 282 / 366 / 358
FBP / °C / 368 / 294 / 373 / 367
Flash point / °C / 68 / 66 / 71
CFPP / °C / -33 / -39 / - 14 / - 33
KV @ 40 C / mm2/s / 3.04 / 1.79 / 3.15 / 3.08
Poly-aromatics / % m/m / 4.3 / <0.1 / 7.3 / 5.0
Mono-aromatics / % m/m / 14.1 / 1.7 / 31.0 / 12.9
Carbon / % m/m / 86.8 / 85.9 / 87.1 / 86.3
Hydrogen / % m/m / 13.2 / 14.4 / 12.9 / 13.1
C/H ratio / 1.82 : 1 / 2.01 : 1
LHV / MJ/kg / 42.8 / 43.9 / 42.4 / 42.5
Cu corrosion / 1a / 1b / 1a / 1a
Conradson Carbon / % m/m / 0.0 / <0.01 / <0.01
Ash / % m/m / 0 / <0.01 / <0.01 / <0.01
Water / mg/kg / 36 / 35 / 50 / 40
Acid No. / mg KOH/g / 0.01 / <0.01 / 0.02 / 0.01
Oxidation Stability / g/m3 / <1 / 10 / 0.2 / 0.3
HFRR / µm / 375 / 386 / 389 / 237
FAME / Nil / Nil / Nil / 5% v/v
Sulphur / mg/kg / 3 / 307 / 7
D-1 / EN 590 :
pre-1996 / 1550
D-2 / EN 590 :
2000 / 280
D-3 / EN 590 :
50 ppm S / 38
D-4 / EN 590 :
10 ppm S / 8

Table 2Gasoline Analyses

Fuel Code / G-1 / G-2 / G-3
Fuel
Description / Units / EN 228:
Year 2000 / EN 228:
50 ppm S / EN 228:
10 ppm S
Characteristic / Result / Result / Result
RON / 96.4 / 96.8 / 96.8
MON / 85.3 / 86.0 / 86.0
Density / kg/m3 / 753 / 749 / 748
RVP / kPa / 58.7 / 57.7 / 57.7
E70 / % v/v / 29.4 / 32.5 / 32.5
E100 / % v/v / 50 / 51.2 / 51.2
E150 / % v/v / 85.5 / 86.1 / 86.1
FBP / °C / 195 / 193 / 193
Residue / % v/v / 1.0 / 1.1 / 1.1
Olefins / % v/v / 8.8 / 9.9 / 9.9
Aromatics / % v/v / 35.4 / 33.4 / 33.4
Benzene / % v/v / 0.8 / 0.6 / 0.6
Sulphur / mg/kg / 143 / 45 / 6
Induction time / minutes / 693 / >480
Existent gum / mg/100ml / <1 / <1
Cu Corrosion / OK / OK
Lead / mg/l / <1 / <1 / <1
Phosphorus / mg/l / <1 / <1 / <1
Carbon / % m/m / 86.3 / 86.0 / 86.0
Hydrogen / % m/m / 13.0 / 13.2 / 13.2
Oxygen / % m/m / 0.7 / 0.8 / 0.8

Due to the differing tasks of the partners, not all partners tested all fuels. Some partners also tested alternative fuels, including RME (neat and blends), oxygenated fuels and natural gas.

TUG tested a neat biodiesel (RME)
VTT tested a 30% blend of RME in D5
VTT and MTC tested a 10% ethanol blend in D5
MTC tested 2% used engine oil in D5 as a simulation of high oil consumption

3.3.Lubricant Selection

A common batch of lubricant was used for the programme in order to minimise effects from differing lubricants. The lubricant was selected as being representative of current typical European lubricant quality, i.e. a good quality, high volume, conventional mineral oil formulation, meeting the following specification :

-15W-40

-ACEA Class A3 / B3 for light duty

-ACEA Class E3 for heavy duty

-Sulphur content : 0.4 – 0.8% m/m

This oil was suitable for use in both light duty gasoline and diesel engines and in heavy duty diesel engines. Analytical details on the lubricant are shown in Appendix 1

4.Engines, vehicles and after treatment technologies tested

4.1.Overall programme plan

Selection of the engines, vehicles and exhaust after-treatment technologies to be tested in the overall programme was made in view of the objectives to develop representative emissions factors for current and future vehicle fleets. The potential benefits available from those technologies expected to be used to meet the emissions control requirements of Euro-4 and beyond would also be identified. A range of vehicle technologies from Euro-1 through to Euro 4-5, including a range of engine and combustion system types and a range of exhaust after-treatment technologies were included in the test matrix.. The overall programme plan for the measurement campaign was documented in Deliverable 5 [9].

The engines and vehicles considered in this Deliverable only include those from partners who tested more than one fuel and hence where fuel effects can be investigated. These tests are shown in the measurement matrix in Tables 3-5

Table 3Heavy duty diesel engines/vehicles measurement matrix

Partner / Engine Type / Emission Class / Vehicle /
Engine Model / Model Year / Cubic capacity [dm3] / Injection System / Power [kW] / rpm [min-1] / Exhaust after-treatment / Fuels tested
AVL / HDD engine / EU 3 / Scania / 2002 / 11.7 / Unit inj / 300 / 1800 / None / D2, D3, D4, D5, D6, D7
HDD engine / EU 4 / AVL prototype / 2002 / 10.6 / Unit inj / 300 / 1900 / cooled EGR / CRT / D3, D4, D5, D7
HDD engine / EU 5 / AVL prototype / 2002 / 11.7 / Unit inj / 300 / 1800 / SCR / urea / D3, D4, D5, D7
TUG / HDD vehicle / EU 3 / IVECO / None / D2, D4, D5 & RME
HDD Bus / EU 3 / Merc Citaro / None / D2, D4, D5 & RME
HDD Bus / EU3 + / Merc Citaro / Oxi-cat / D2, D4, D5 & RME
HDD Bus / EU 3 + / Merc Citaro / Particulate cat / D2, D4, D5 & RME
HDD Bus / CNG / Evobus / CNG
Volvo / HDD engine / EU 1 / Volvo / 1992 / 11.97 / DI / 247 / 1900 / None / D1, D4, D5
HDD engine / EU 3 / Volvo / 2000 / 12.13 / DI / 380 / 1800 / None / D2, D4, D5
HDD engine / EU 3+ / Volvo / 2000 / 12.13 / DI / 380 / 1800 / CRT / D5, D4
VTT / HDD engine / EU 2 / Volvo DH10 / 9.6 / 210 / 2000 / None / D2, D4, D3, D5
HDD engine / EU 4 / Volvo DH10 / 9.6 / 210 / 2000 / CRT / D4, D3
HDD engine / EU 3 / Scania DC11 / 10.6 / 250 / 1900 / None / D2,D4, RME30
HDD engine / EU 4-5 / ScaniaDC 11 / 11.6 / 251 / 1900 / SiNOx / D4

Table 4Light duty diesel vehicle measurement matrix

Partner / Engine Type / Emission Class / Vehicle/Engine Model / Model Year / Cubic capacity [cm3] / Injection System / Power [kW] / rpm [min-1] / Exhaust after-treatment / Fuels tested / Test Temperature
CONCAWE / DI diesel / EU 3 / VW Golf 1.9 Tdi / 2002 / 1896 / ? / Oxi-cat / D2,D3,D4,D5,D6, D7 / Standard
DI diesel / EU 3 / P-607 2.2 HDI / 2001 / 2179 / Common rail / 101 kW / Additised DPF / D2,D3,D4,D5,D6, D7 / Standard
IFP / Diesel / EU3 / VW Golf TDI / 1.9 / DI / Oxi-cat / D2,D3,D4,D5 / Standard
Diesel / EU3+ / P-307 HDI / 2 / Common rail / PM trap / D2,D3,D4,D5 / Standard
MTC / Diesel / EU 3+ / P-607 / HDI / DPF / D2, D5 / Standard
Diesel / EU 3 / P-406 / Common Rail / Oxi-cat / D2, D5 / Standard, -7, -15
" / " / " / EtOH-D5 / Standard
Diesel / EU 3 / VW Golf / DI / D2, D5 / Standard, -7, -15
LAT / Diesel / EU 1 / VW Golf / 1.9 / None / D2,D3,D4,D5 / Standard
Diesel / EU 2 / VW Golf / 1.9 / oxi-cat / D2,D3,D4,D5 / Standard
Diesel / EU 3 / R. Laguna / 1.9 / DI / None / D2,D3,D4,D5 / Standard
Diesel / EU 3+ / R. Laguna / 1.9 / DI / Cat DPF / D2,D3,D4,D5 / Standard
Diesel / EU 3+ / R. Laguna / 1.9 / DI / Add DPF / D2,D3,D4,D5 / Standard

Table 5Gasoline vehicle measurement matrix

Partner / Engine Type / Emission Class / Vehicle/Engine Model / Model Year / Cubic capacity [cm3] / Injection System / Power [kW] / rpm [min-1] / Exhaust after-treatment / Fuels tested / Test Temperature
CONCAWE / DI gasoline, stoichiometric / EU 3 / R. Megane, 2.0 ide / 2001 / 1998 / DISI / 104 kW / TWC / G1,G2,G3 / Standard
DI gasoline, lean burn / EU 3 / C-5 2.0 HPI / 2002 / 1997 / DISI / 107 kW / NOx storage / G1,G2,G3 / Standard
IFP / Gasoline MPI / EU 3 / R. Megane / 1.6 / MPI / TWC / G1, G2, G3 / Standard
DI gasoline, lean burn / EU 3 / C-5 HPI / 2 / DISI / TWC + NOx trap / G1, G2, G3 / Standard
MTC / Gasoline MPI / ULEV / Honda Accord / MPI / TWC / G1,G3 / Standard, -7, -15
DI gasoline, stoichiometric / EU 3 / Mitsubishi Charisma / DISI / TWC / G1,G3 / Standard, -7, -15
LAT / Gasoline MPI / EU 1 / BMW 318 / MPI / TWC / G1,G3 / Standard
Gasoline MPI / EU 3 / Toyota Corolla / 1.8 / MPI / TWC / G1,G3 / Standard

5.Drive cycles and test conditions

The specific detailed sampling and testing protocol for the measurement of exhaust gas particulate emissions was as described in the report of Work Package 300 [6].

The details on the driving cycles used for the tests were described in Deliverable 5 from Work Package 400 [9]. In all cases the standard legislative emissions test cycles for light duty vehicles and heavy duty engines were used [1,2]. These were supplemented by some “real world drive cycles” which were developed under the ARTEMIS programme, and several steady state conditions.

For light duty vehicles, the following basic daily test sequence was used:

Fuel change
Conditioning : Gasoline cars 1*ECE + 2*EUDC, diesel cars 3* EUDC
Cold soak
NEDC test
Hot start NEDC test
ARTEMIS road test
ARTEMIS urban test
ARTEMIS motorway test
Steady state tests : 50 km/h, 90 km/h, 120 km/h
End of test

For heavy duty engines, the relevant legislative heavy duty engine emissions test cycles, ESC and ETC tests, were used, together with a series of extended steady state modes covering both on-cycle and off-cycle measurement points. A common test sequence was required in order to obtain comparable results from different fuel/engine combinations. This general daily test sequence was as below:

Heavy Duty Engine Test Sequence / Measurements
Warm-up(Road load, followed by 0,5 h at full load, rated speed)
Dummy ESC

/ Full “Particulates” measurement suite
(WP 300 protocol).
Regulated gaseous and PM emissions

/ Full “Particulates” measurement suite
(WP 300 protocol).
Regulated gaseous and PM emissions
Extended Steady States (Range of on-cycle and off-cycle conditions*)

SS1 - ECE R-49 Mode 2

SS2 - ESC Mode 5 (50% load, speed A)
SS3 - ESC Mode 12 (75% load, speed C)
SS4 - Road load, speed 50/50 A/C
SS5 - 25% load, speed A-10%
SS6 - 50% load, 50% speed

/ Full “Particulates” measurement suite
(WP 300 protocol).
SMPS in place of CPC to provide size distribution on wet branch
NOTE : For SMPS measurements at all extended steady state conditions

Stabilise engine, temperatures, gaseous emissions
Run series of 2 minute SMPS scans
Stop after 3 stable SMPS scans are achieved

For heavy duty vehicles, in addition to steady state modes, specific transient test cycles were employed, selected by TUG from the ARTEMIS cycles, according to the measurement results in ARTEMIS, to cover the most interesting engine operating regimes. Specific city bus cycles were also defined by TUG.