Development & Implementation of Particle

Number Measurement for Vehicle Emissions

Regulation

8 - 9 June 2010 : Metrology of Airborne

Nanoparticles, Standardisation and

Applications (MANSA)

Current Vehicle Emissions Regulations

• New cars and vans: Euro 4 (Directive 70/220/EEC as amended or ECE Regulation 83.05)

• Engines of new HGVs and buses: Euro V (Directive 2005/55/EC as amended or ECE Regulation 49.05)

• These standards all control particle emissions by means of limits on total Particulate Mass

• Measurement technique involves passing a sample of diluted exhaust through two filter papers in series and

measuring change in mass of (conditioned) filter papers

UNECE Working Party 29 & GRPE

• WP.29 is the United Nations working party with the mandate to develop harmonised regulations on motor

vehicle construction/performance e.g. UNECE

Regulations 49 and 83 on vehicle emissions.

• The Working Party on Pollution and Energy (GRPE) is

the subsidiary body of WP.29 that prepares regulatory proposals on pollution and energy efficiency.

• Within GRPE proposals are developed by “informal

groups” tasked with work on specific subject areas.

Particle Measurement Programme

• Concerns of health experts over nano-particles

• Concerns over the sensitivity of PM at advanced technology emissions levels and its ability to drive technology capable of efficiently controlling nanoparticles

• Decision taken to develop new metrics which would enable legislation to force highly efficient particle emissions controltechnologies, IF a political decision was taken to do so

• PMP established as a GRPE informal group in 2001 to develop these

Particle Measurement Programme Mandate

• To develop new techniques to replace or complement Particulate Mass measurement;

– Including a description of the test procedures, sampling and measurement equipment.

– Applicable to Light & Heavy Duty testing

– Suitable for use on transient test cycles

• To provide data on the performance of different

technologies, including wall-flow Diesel Particulate Filter

equipped vehicles, according to the new measurement procedures

PMP Participants

Governments

• France, Germany, Greece, Japan, Korea, Sweden,

Switzerland & UK

• European Commission DG JRC

Industry

• AECC, CONCAWE, OICA

Laboratories

• AEA, EMPA, JRC, LAT, AVL-MTC, NMVERL, NTSEL,

Ricardo, RWTUV, Shell, UTAC, Volvo, VTT,

Environment Canada, Daimler

PMP Phases I & II Identification &

Evaluation of Candidate Techniques

Sampling/Conditioning Systems

• Full flow dilution (+ secondary dilution)

• Full flow dilution + thermodenuderor thermodiluter

• Rotary dilution

• Raw exhaust

Measurement Techniques

• Gravimetric (modified US 2007)

• Filter + chemical analysis

• TEOM

• Laser Induced Incandescence

• QCM

Measurement Techniques (cont)• Photoacoustic absorption

• Coulometric

• Photoelectric charging

• Light extinction

• Laser Light Scattering

• Differential Mobility Spectrometer

• Optical counter (CPC)

• Electrical Mobility

• ELPI

• Diffusion battery

• Diffusion charger

Recommended Technique – Particle

Number

• Full or Partial Flow Dilution System with HEPA & HC filtered dilution air

• Cyclone Pre-classifier

• Sample thermal conditioning: heated dilution, evaporation tube, dilution

• Condensation Particle Counter 23nm (50%) cut point

Merits of Recommended Technique

• Excellent sensitivity at low emissions levels

• Acceptable particle losses

• Fully compatible with existing regulatory emissions sampling systems

• Robust in a type approval environment

• Good repeatability

• Good reproducibility through good sample definition by sample pre-conditioning & defined CPC cut-point

• Availability of components

PMP Phase III - Validation

• Separate Light & Heavy Duty Validation Exercises

Aims

• Assess repeatability and lab-lab reproducibility of proposed technique

• Assess performance levels of different vehicle/engine technologies

• Assess performance of various measurement systems

Overview

• Measurements at ≥5 laboratories

• Bookend testing at DG-JRC

• Golden Engineer, Golden Vehicle/Engine & Golden System

• Optional additional vehicles & systems

• Additional industry Round Robin in parallel to Heavy Duty Validation Exercise

Light Duty Results – All vehicles

1.0E+09

1.0E+10

1.0E+11

1.0E+12

1.0E+13

1.0E+14A

u-D

PF

DP

F#

1

DP

F#

2

DP

F#

3

DP

F#

4

DP

F#

5

MP

I

GD

I#1

GD

I#2

GD

I#3

no

n-D

PF

#1

no

n-D

PF

#2

no

n-D

PF

#3

no

n-D

PF

#4

no

n-D

PF

#5

no

n-D

PF

#6

Pa

rtic

le N

um

be

r E

mis

sio

ns

[#

/km

]

0%

20%

40%

60%

80%

100%

Co

V (

%)

31%

35%33%

27%

78%

32%

25%

6%

26%

8%

2% 4%5%

3%

7%

4%

x 7

x 40-140x 350-700

Repeatability levels improved as emissions levels increased across all vehicle types

Below 2x1011/km

0.3-1x1013/km

>2x1013/km

PN Sensitive To DPF Fill State

0

2E+10

4E+10

6E+10

8E+10

1E+11

1.2E+11

1.4E+11

1.6E+11

0 20 40 60 80 100 120 140

Distance (km)

Pa

rtic

les

/km

NEDC [#/km]

• DPF Regeneration occurred prior to first test

• PN decreased from test to test as DPF filled contributing to

apparent poor repeatability

Light Duty Validation Conclusions

• Particle number measurement equipment presented no significant functional or maintenance challenges during the programme

• Particle number

– DPF diesels emit ~1011 /km, similar to conventional petrols

– GDIs emit 1012 – 1013 /km

– Non-DPF diesels emit ~5x1013 /km

• Particle number sensitive to DPF fill state, preconditioning of the vehicle and DPF porosity - ‘true repeatability’ masked

• Vehicle/DPF stabilisation recommended

June 2007 GRPE

• Adoption of Particle Number measurement in Regulation 83 (passenger car emissions) proposed

• Several nations expressed a view that proposal was premature with remaining issues to be resolved in particular regarding;

– calibration procedures

– VPR & PNC specifications

– Potential system to system offsets

• Proposal not adopted by GRPE

• GRPE endorsed a ‘Road Map’ of activities to allow a revised proposal to be considered by GRPE in Jan 2008

PMP Road Map

• Compile additional PN results from outside of the PMP Validation exercise

– Data was received from AECC, CARB, JAMA, Sweden, Concawe, UK, Toyota and Volkswagen

• Improve calibration procedures

• Analyse accumulation of errors/system tolerances

• Demonstrate improved calibration procedures

Consolidation of Particle Number Data

1.00E+09

1.00E+10

1.00E+11

1.00E+12

1.00E+13

1.00E+14

Au-DPF

DPF-aCord

DPF-a

Cord-D

PF-b

Cord-D

PF-c

Cord-D

PF-d

Cord-D

PF-e

Cord-D

PF-f

Cord-D

PF-g

Cord-D

PF-h

Cord-D

PF-hM

PI-aM

PI-bM

PI-cG

DI-aG

DI-b

GDI-c

GD

I-dG

DI-eG

DI-fG

DI-fnon-D

PF-anon-D

PF-bnon-D

PF-cP

art

icle

Nu

mb

er

Em

iss

ion

s [

#/k

m]

Matter/TSI results shown shaded, Horiba SPCS results shown unshaded

DPFs MPIs

GDIs

non-DPFsCARB

VW

DfT/Ricardo

JAMA/Toyota

AECC/AVL-MTC

Improved Calibration Procedures

• The following key revisions to the procedures were agreed

– VPR will be calibrated for “particle concentration reduction factor” (a combination of particle losses and dilution) which must not be excessively size dependent

– PNC will be calibrated to reference electrometer level, either directly or indirectly

• Correcting out differences in particle losses and PNC response reduces potential offset between systems

• EMPA, METAS, TSI & AEA undertook measurements demonstrating the improved calibration procedures and their repeatability

PNC Gradient Calibration

PNC All Validations - Gradient

0.7

0.75

0.8

0.85

0.9

0.95

1

TSI 3010

s/n

70410281

TSI 3010

s/n 2400

w ith

primary cal

factor

TSI 3010

s/n 2400

TSI 3010

s/n

70410281

TSI 3010

s/n 2435

TSI 3010

s/n 2400

TSI 3010

s/n

70410281

TSI 3010

s/n 2435

TSI 3790

s/n

70725185

TSI 3790

s/n

70725186

Grimm

5.403 s/n

54300307

Gra

die

nt

EMPA METAS

TSI

AEA

Validations by Secondary Procedure (reference PNC) Shaded

VPR pcrf Repeatability

• Repeatability very good at pcrf settings used for DPFs (typically

~150) and GDIs (typically ~600)

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

98 115 111 114 320 819 1151 2181

particle concentration reduction factor

Co

V (

%)

EMPA

METAS

AEA

Accumulation of Errors Analysis

• Analysis performed by the UK National Physical Laboratory according to ISO Guide to the Expression of

Uncertainty in Measurement (GUM) taking account of improvements made at August & October PMP

meetings.

• Uncertainty at typical settings for post DPF

measurement was estimated to be around 15%.

• The most significant factors contributing to uncertainty

are the PNC calibration and the allowable tolerance on

VPR pcrf validation checks

January 2008 GRPE & Reg692/2008

• Revised proposal inserting Particle Number

measurement into Regulation 83 adopted by

GRPE & subsequently by WP29 in June 2008

• EU Regulation 692/2008 adopted a PN limit for

diesel cars and vans of 6x1011 /km as part of the

Euro 5 standard

• PN limit for GDI petrol cars to be adopted at

Euro 6 (2015)

Heavy Duty Validation Exercise

• Golden Engine Euro III + CRT

• Two Horiba SPCS Golden

Systems

• Participating Labs: JRC, AVL-

MTC, Ricardo, UTAC, EMPA

• Matrix of 5 test cycles including

steady state, transient, hot start,

cold start, current & future regulatory cycles

• Jan 2008 – Nov 2009

Heavy Duty Key Observations

1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

0 300 600 900 1200 1500 1800

Time [s]

PN

[c

m-3

]

JRC

AVL_MTC

RCECVS

Hot W HTC• Dilution system background significant over low emission cycles in some labs

5.3E+09

4.2E+102.8E+10

6.2E+09

7.7E+10

3.7E+11

0.0E+00

5.0E+10

1.0E+11

1.5E+11

2.0E+11

2.5E+11

3.0E+11

3.5E+11

4.0E+11

WHTC Cold WHTC Hot WHTC

Combined

WHSC ETC ESC

Cycle

Pa

rtic

les

/kW

h

All data

• Highest emissions from cold start test cycle

Agreement of PN Measurement Systems From Different Suppliers

• Calibrated systems generally agreed with Golden Particle

Measurement System within ±15%.

Heavy Duty Validation Conclusions

– PN emission levels over cold WHTC were ~4×1011 #/kWh. At these emission

levels, dilution system background levels are insignificant.

– PN emission levels over hot start WHTC and ETC cycles were <2×1010 #/kWh.

– Passive regeneration occurring over the WHSC and ESC cycles results in an

increase of the emissions, up to 6×1010 #/kWh, and in variability due to

influence of initial DPF fill state

– Background in some labs/dilution systems was a substantial influence on hot

start cycles

– Alternative systems correlated closely with the GPMS

– Repeatability and reproducibility levels, respectively ranged from:

• ~20% and ~40%, respectively, over cold WHTC

• ~70% and ~80%, respectively, over WHSC, due to passive regeneration

related emissions.

Ongoing Issues

• Adoption of PN Measurement & Limits in Heavy

Duty Emissions legislation

• Further investigation of factors influencing

“particle concentration reduction factor”

calibration. Improvement & simplification of

procedures

• Investigation of significance of <23nm solid

particles

Thank you

Acknowledgements

Jon Andersson – Ricardo Consulting Engineers

Penny Dilara, Giorgio Martini, Barouch Giechaskiel, Thanasis Mamakos – DG JRC

Ian Marshall - AEA

Dirk Bosteels, John May – AECC; Markus Kasper – Matter Engineering;

Les Hill, Daniel Scheder – Horiba; Ken Rose - Concawe

Paul Quincey, Richard Gilham – NPL; Juerg Schlatter – METAS

All PMP Working Group Members