Development & Implementation of Particle Number Measurement for Vehicle Emissions Regulation

Transcription

1 Development & Implementation of Particle Number Measurement for Vehicle Emissions Regulation 8-9 June 2010 : Metrology of Airborne Nanoparticles, Standardisation and Applications (MANSA)

2 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

3 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.

4 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 control technologies, IF a political decision was taken to do so PMP established as a GRPE informal group in 2001 to develop these

5 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

6 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

7 PMP Phases I & II Identification & Evaluation of Candidate Techniques Sampling/Conditioning Systems Full flow dilution (+ secondary dilution) Full flow dilution + thermodenuder or 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

8 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

9 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

10 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

11 Light Duty Results All vehicles 1.0E E E E E E % 80% 60% 40% 20% 0% Au-DPF DPF#1 DPF#2 DPF#3 DPF#4 DPF#5 MPI GDI#1 GDI#2 GDI#3 non-dpf#1 non-dpf#2 non-dpf#3 non-dpf#4 non-dpf#5 Particle Number Emissions [#/km] non-dpf#6 CoV (%) 31% 35%33% Repeatability levels improved as emissions levels increased across all vehicle types x 7 27% 78% 32% Below 2x10 11 /km 0.3-1x10 13 /km 25% 6% x % 8% >2x10 13 /km x % 4% 5% 3% 7% 4%

12 PN Sensitive To DPF Fill State 1.6E E+11 NEDC [#/km] 1.2E+11 Particles/km 1E+11 8E+10 6E+10 4E+10 2E Distance (km) DPF Regeneration occurred prior to first test PN decreased from test to test as DPF filled contributing to apparent poor repeatability

13 Light Duty Validation Conclusions Particle number measurement equipment presented no significant functional or maintenance challenges during the programme Particle number DPF diesels emit ~10 11 /km, similar to conventional petrols GDIs emit /km Non-DPF diesels emit ~5x10 13 /km Particle number sensitive to DPF fill state, preconditioning of the vehicle and DPF porosity - true repeatability masked Vehicle/DPF stabilisation recommended

14 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

15 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

16 non-dpf-b non-dpf-c Consolidation of Particle Number Data Matter/TSI results shown shaded, Horiba SPCS results shown unshaded 1.00E E E E E+10 CARB VW DfT/Ricardo JAMA/Toyota AECC/AVL-MTC DPFs MPIs GDIs 1.00E+09 non-dpfs Particle Number Emissions [#/km] Au-DPF DPF-a CordDPF-a Cord-DPF-b Cord-DPF-c Cord-DPF-d Cord-DPF-e Cord-DPF-f Cord-DPF-g Cord-DPF-h Cord-DPF-h MPI-a MPI-b MPI-c GDI-a GDI-b GDI-c GDI-d GDI-e GDI-f GDI-f non-dpf-a

17 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

18 PNC Gradient Calibration PNC All Validations - Gradient Validations by Secondary Procedure (reference PNC) Shaded 1 EMPA METAS TSI AEA Gradient TSI 3010 s/n TSI 3010 s/n 2400 w ith primary cal factor TSI 3010 s/n 2400 TSI 3010 s/n TSI 3010 s/n 2435 TSI 3010 s/n 2400 TSI 3010 s/n TSI 3010 s/n 2435 TSI 3790 s/n TSI 3790 s/n Grimm s/n

19 VPR pcrf Repeatability Repeatability very good at pcrf settings used for DPFs (typically ~150) and GDIs (typically ~600) 14.00% 12.00% 10.00% AEA CoV (%) 8.00% 6.00% 4.00% 2.00% EMPA METAS 0.00% particle concentration reduction factor

20 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

21 January 2008 GRPE & Reg 692/2008 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 6x10 11 /km as part of the Euro 5 standard PN limit for GDI petrol cars to be adopted at Euro 6 (2015)

22 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

23 Heavy Duty Key Observations Particles/kWh 4.0E E E E E E E E E E E E E E+09 All data 7.7E+10 WHTC Cold WHTC Hot WHTC WHSC ETC ESC Combined Cycle Highest emissions from cold start test cycle Dilution system background significant over low emission cycles in some labs PN [cm -3 ] 1.0E E E E E E E+00 Hot W HTC JRC AVL_MTC CVS RCE Time [s]

24 Agreement of PN Measurement Systems From Different Suppliers Calibrated systems generally agreed with Golden Particle Measurement System within ±15%.

25 Heavy Duty Validation Conclusions PN emission levels over cold WHTC were ~ #/kwh. At these emission levels, dilution system background levels are insignificant. PN emission levels over hot start WHTC and ETC cycles were < #/kwh. Passive regeneration occurring over the WHSC and ESC cycles results in an increase of the emissions, up to #/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.

26 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

27 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