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Post Euro 6/VI activities
focusing on particle number
B. Giechaskiel, T. Lahde, M. Clairotte, V. Valverde, J. Pavlovic, R. Suarez-Bertoa, T.
Grigoratos, A. Zardini, A. Perujo, A. Marotta, P. Bonnel, G. Martini, P. Dilara
Joint Research Centre, European Commission
2
•Current (solid) particle number (SPN) regulations
•Post Euro 6/VI topics
•Going below 23 nm?
•Going to the tailpipe?
•Particle number PEMS
•Periodical inspection
•Non-exhaust emissions
•Conclusions on particle number
Overview
Paper # (if applicable) 3
(Solid) Particle Number (SPN) regulations
Giechaskiel et al. 2018, Combustion engines, 174, 3-16
(for some categories)
4
New type-approval framework Reg. 2018/858 (replaces Dir. 2007/46/EC)
applicable from 2020 and introduces market surveillance
•Will focus on environmental performance and safety (20% of tests)
•Raise the quality level and independence of type-approval and testing
before a car is placed on the market
–Member states will be able to take measures in their national markets,
instead of having to wait for the type-approval authority of the country
that issued the vehicles’ type-approval certificate.
–National type-approval authorities will be subject to a peer review
•Increase checks of cars that are already on the EU market by Member
States
•European oversight: Forum for exchange of information on enforcement
Market surveillance
5
•Relative good
agreement between
lab and on-road (tests
before SPN-PEMS
introduction)
•No particular issue for
GDIs fulfilling the
6x1012 p/km
•Differences could be
explained in most
cases (e.g. mass,
ambient temperature,
DPF fill state etc)
Lab vs on-road SPN measurements
Giechaskiel et al. 2015, Frontiers, 3, 82
6
Stakeholder event
•Took place in Brussels on the 24th October 2019 with the participation of
more than 120 experts. Preceded by a meeting of academic experts
Main topics
•In use performance monitoring for compliance and enforcement over the
lifetime of the vehicle
•Pollutant emissions to be considered along with CO2/GHG emissions
•Currently non-regulated emissions should also be considered
Emission standards for the future
Presentations are available:
http://ec.europa.eu/growth/content/stak
eholder-event-preparing-future-european
-emission-standards-light-and-heavy-dut
y-vehicles_en
7
•Fuel and technology neutral regulations and emission standards
•Intelligent geo-fencing
•Investigate if and how Remote Sensing can complement the existing
regulatory arsenal
•Investigate if OBD is still necessary in the emissions regulation or it is
only a duty of the OEM towards its clients
•Evaporation losses: to further investigate for fuel neutrality and running
losses
•Two big studies in 2019-2020 to address the issues identified
•Legislative process in Europe can be long. At least two years from the
proposal to the final rule should be estimated.
•Lead time for the industry to adapt its products
Additional topics
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•Emphasis on continuous emission monitoring, but care should be taken
on privacy rules
•Link regulations with impacts: towards averages and (lifetime) totals, and
reducing risks
•Substantial increase in the durability requirements, including Market
Surveillance and In-Service Conformity requirements
•Closer links with On-Board Diagnostics (OBD) and the developments
therein. Regulatory emphasis and signalling for further exhaust emission
sensor development.
•Modelling and cloud monitoring should also be accounted for improved
accuracy and performance
In-use performance monitoring
9
•The Commission is analysing
that the current OBD
requirements (based on NEDC
demonstrations) can be
applied to WLTP (OBD
requirements with WLTP
compulsory from Jan 2022).
•For post-Euro 6/VI legislation,
there is the intention to push
toward OBM (monitoring).
•More focus on ISC and market
surveillance and less at type
approval.
Monitoring particles
GDIs without GPF
OBD limit
Meaningful OBD, SEMS
Giechaskiel et al. 2012, AST, 46, 719-749
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•Help address the question: How much emission control needed and what
expense on fuel consumption is acceptable?
•Air and climate pollutants should not be dealt separately
•No separate standards for different types of fuels and or engines
•Address non-CO2 greenhouse gas emissions
•Energy consumption and CO2 emissions in normal use, including lights,
auxiliaries, winter tires, options, deterioration, etc.
Pollutant and CO2/GHG emissions
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•Sub 23 nm particles and total (i.e. solid and volatile) particles
•NH3 – Ammonia (hazardous, PM precursor, significant contributor to the
formation of Secondary Organic Aerosols)
•HNCO (isocyanic acid)
•NO2 - Less direct NO2 helpful to reduce exposure – Maybe sufficient to be
reported for AQ modelling purposes
•N2O – Nitrous oxide (High GHG potential, ozone depleting substance)
•CH4 – Methane (High GHG potential)
•PAHs – polycyclic aromatic hydrocarbons and Aldehydes
•Brake, tire, and road wear emissions: particle sizes and composition.
Non-regulated emissions
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•Diesel: <50%
•GDIs: 20%
•CNG: 100%
•Motorcycles: >60%
•Fractions are very
important only when
emissions are close
to the SPN limit
Is there a need to regulate SPN <23 nm?
Giechaskiel et al. 2018, Combustion engines, 174, 3-16
Giechaskiel 2018, IJERPH, 15, 304
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•Extreme example of PMP systems
•The difference between the systems increases at lower particle sizes.
•The final result depends on the CMD (median size) of the size distribution
Can we measure SPN <23 nm (accurately)?
Giechaskiel et al. 2017, AST, 51, 626-641
Assumed size
distribution
14
•Volatile artefact: Renucleation of volatiles after the evaporation tube or the
catalytic stripper results in volatile particles being counted as solid
•Cold start (high amount of volatiles), DPF equipped vehicles (low soot).
•Even with catalytic stripper volatile artifact at the 3 nm range can appear
Volatile artifact
Giechaskiel et al. 2017, AST, 51, 626-641
15
•Solid artefact: Measurement of solid particles that are formed after the
vehicle tailpipe (typical sizes at 10 nm or lower)
•Typically at high exhaust gas temperatures at unconditioned sampling lines
•DPF regenerations, Steady states of gasoline vehicles/motorcycles
Non-volatile (solid) artifact
Giechaskiel et al. 2018, Combustion engines, 174, 3-16 Giechaskiel et al. 2015, SAE 2015-24-2512
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•Light-duty inter-laboratory exercise with two golden instruments with
catalytic stripper measuring both >10 nm and >23 nm
–European phase finished
–Japan, China and maybe US will participate
•Heavy-duty inter-laboratory exercise with one golden instrument with
catalytic stripper measuring both >10 nm and >23 nm
–European phase will finish in June
–China and US will participate
•Horizon 2020 projects exploring other sampling methodologies, counting
principles and minimum size
–DownToTen
–Sureal
–PEMS4Nano
Sub-23 nm activities
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Objective: Introduction to heavy-duty engines type approval
•First analysis of potential benefits/issues presented (heavy-duty)
–Primary dilution (cold / hot)
–Losses (thermophoresis, agglomeration)
–Volatile removal efficiency (CS or ET)
–Pressure effects, Time alignment etc.
•Correlation with other methods (CVS and partial flow system) and
advantages/disadvantages to be checked
•An inter-laboratory correlation exercise is on-going (European part to be
finalised in June). China and US will follow
•To be extended to light-duty vehicles
Raw exhaust sampling (fixed dilution)
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Uncertainty SPN PEMS:
40 – 65%. Today:
•At the higher end HDV
•In the middle LDV
•At the lower end CPC
based systems
Robust for most
conditions (regeneration,
ambient temperatures,
volatiles, fuels) however
until recently still some
issues were observed
SPN PEMS: overview of all results
Giechaskiel et al. 2018, Combustion engines, 174, 3-16
Giechaskiel et al. 2018, JAS, 123, 161-170
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•No CVS uncertainty was subtracted because the evaluation was done
compared to PMP systems
•Size dependency is higher than 15% when GMD is lower <30 nm or >75 nm
•Particle losses are typically lower than 25%
Preliminary SPN margin evaluation (HDV)
Giechaskiel et al. 2018, Env Research, 166, 251-260
Giechaskiel et al. 2019, Sustainability, 11, 1067
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Objective: Tamper-proof
methods for exhaust
assessment
Initiative of VERT
supported by Switzerland,
the Netherlands, Belgium,
Germany and EU
Proposal: Particle number
for DPF (TNO)
Technical specifications
New Periodical Technical Inspection (NPTI)
Giechaskiel et al. 2018, Combustion engines, 174, 3-16
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PMP on brakes focuses on the development of a standardized test
procedure for sampling and measuring brake wear particles (January 2020).
Major steps taken
•Development of a real-world braking test cycle (July 2018)* - There is a
dedicated Task Force (TF1) led by JRC working on the cycle related
aspects
•Provide a set of minimum requirements for the emissions setup (January
2020) - There is a dedicated Task Force (TF2) led by JRC working on the
cycle related aspects
Regarding tyre wear particles there is a decision to wait for the development
of the abrasion rate method and then examine the relationship between
abrasion rate (material loss per km) and particle emissions
Non-exhaust particle emissions
https://data.mendeley.com/datasets/dkp376g3m8/1
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•For some technologies there is a significant fraction of particles below 23
nm. In some cases absolute levels seem to be critical, i.e. high emitters
cannot be identified with the PMP 23nm procedure
•Extreme differences between lab and on-road were not identified for
particle number (non-GPF GDIs); this need to be verified for Euro 6d
vehicles
•Decreasing the lower size to 10 nm seems possible with minimum risks:
definition of PCRF (losses), artifacts, equipment investment (PMP and
PEMS)
•Decreasing the lower size below 10 nm has high risk (today’s
instruments). Input is needed from Horizon 2020 projects
Conclusions
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•PEMS and PMP systems can have differences 40-65%. Although up to
35% can come from the particle detector another 20% can come from the
different location
•Particle “losses” (e.g. agglomeration, thermophoresis), but also solid
particle formation (solid artefact) have been seen (affecting sub-10 nm
measurements)
•Tailpipe sampling is investigated for type approval and seems a step
forward (less prone to artifacts and particle transformations). However
improper setup has shown artefacts from condensation.
•Future regulations will focus on best available technology but they will
also be technology neutral.
Conclusions
