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
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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
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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
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94 tests on-dyno, 283 sub-cycles
Comparison of PEMS-PN (all in parallel) with CVS reference,
calibration
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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)
PN (cm-3)
PN (cm-3)
• Volatile artifacts with PEMS-PN without VPR
• VPR important
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
Pass vs PMP
23°C
(<6e11 km-1)
PEMS-PN 1
PEMS-PN 2
PEMS-PN 3
PEMS-PN 4
PEMS-PN 5
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
Thanks for your attention!