Feasibility report on the extension of the RDE procedure to particle number Progress update Francesco Riccobono, Barouch Giechaskiel, Pierre Bonnel Institute for Energy and Transport Joint Research Centre 03 February 2014

Outline Introduction Comparison of PMP systems Comparison of PEMS-PN systems vs PMP On-road tests Extreme conditions Moped (Oil particles) Regeneration Calibration issues Conclusions

Scope and methods Aim of the feasibility study: Assess and validate the application and performance of portable PN instrumentation relative to each other and to a standard instrument. Evaluation criteria: -Linearity of the portable system with the reference system on-dyno -Stability and performance of long sampling on-road

Experimental setup 5 candidate PEMS-PN instruments 5 vehicles (3 GDI, 1 MPI and 1 Diesel w/DPF) 5 cycles (NEDC, WLTP, RDE, ARTEMIS, Steady State) at 8 and 23 C 94 tests on-dyno, 283 sub-cycles Comparison of PEMS-PN (all in parallel) with CVS reference, calibration 8 tests on-road (GDI vehicle) 4 PEMS-PN candidates (1 at a time) + 1 Reference candidate instrument always on board + gas PEMS Two types of tests: 1 and 2 hour long

Comparison of PMP systems CVS vs Tailpipe: Good correlation until CVS detection limit

Detection limit PMP

PMP systems Differences +/-25% MPI

PEMS-PN vs PMP

PEMS-PN vs PMP

On-road tests All instruments demonstrated to be stable over long sampling tests on-road (2 hours) All instruments showed similar deviations from the reference PEMS-PN on-road and on-dyno

Moped tests (extreme condition 1) Volatile artifacts with PMP + 3 nm CPC Cut-off size important CPC CPC PEMS PN with VPR

Regeneration (extreme condition 2) Volatile artifacts with PEMS-PN without VPR VPR important PN (cm-3) PN (cm-3)

Detailed analysis of extreme cases Ideally the system should have both VPR and 23 nm cut-off Minimum temperature of 200°C can be accepted with enough residence time (info from manufacturers needed) or other technologies (e.g. catalytic stripper) Cut-off size requirement will apply

Calibration and sensitivity analysis Preliminary results show the sensitivity to bigger particles (impactor or cyclone might be required)

Calibration and sensitivity analysis Sensitivity analysis to be conducted Calibration procedures to be defined Volatile removal efficiency tests to be done

Specific conclusions 1/2 PMP systems (CVS vs tailpipe) within ± 25% On-road tests showed consistent results with lab tests (i.e. similar deviation from the reference PEMS-PN) Good stability over long sampling on-road PEMS-PN vs PMP: Accuracy within a factor 1.4-2 Low ambient temperature tests indicated sometimes big deviation from PMP

Specific conclusions 2/2 The diffusion charging principle was shown to be an acceptable technique alternative to CPC Extreme conditions (moped, regeneration) confirmed the need of proper thermal pre-treatment and suitable cut-off size Temperature ≥200°C Residence time requirement and/or other techniques Cut-off around 23 nm Lab calibration identified the need of larger sizes cut-off To be discussed cut-off above 500nm

Summary PEMS-PN 1 PEMS-PN 2 PEMS-PN 3 PEMS-PN 4 PEMS-PN 5 Pass vs PMP 23°C (<6e11 km-1) Fail vs PMP 23°C (>6e11 km-1) Pass vs PMP 8°C (<6e11 km-1) Fail vs PMP 8°C (>6e11 km-1) Regeneration On-road PEMS-PN 1 PEMS-PN 2 PEMS-PN 3 PEMS-PN 4 PEMS-PN 5

Thanks for your attention!