Future Powertrain Conference 24 th February C 2016 HORIBA Ltd. All rights reserved.

Recent and Future Developments In The Legislation and Measurement of Particle Number for Type Approval, In Service Conformity and Real Driving Emissions Future Powertrain Conference 24 th February 2016 C 2016 HORIBA Ltd. All rights reserved.

Introduction The Rise of Particle Number (PN) Measurement in Exhaust Emissions Legislation The applications of PN counting have increased since its original creation under the GRPE PMP Working Group in the early 2000s EU Light Duty Vehicles (original application) EU HD Onroad NRMM Stage V (scheduled 2019) Measurement from raw (undiluted) exhaust for some applications Originally PN sampling only from CVS or from Partial Flow Dilution Systems Increasing interest to reduce the size of particles counted from 23nm to 10nm In the case that new combustion techniques / after-treatments generate smaller particles?

Why Particle Number? In the late 1990s, the Particle Measurement Program (PMP) was formed under GRPE at the UNECE to review PM measurement PM emissions were an increasing concern for public health New diesels vehicles were producing lower PM mass but there were concerns over possible increase in nano-particles that may be harmful PM emissions from new engine/vehicle technologies were considered to be reaching the limit of the existing legislative gravimetric measurement technique. It was considered necessary to review the available PM measurement principles and instrumentation for possible future legislation requiring reduction of PM emissions After a 10 year program of research, development, validation and correlation, the PMP method of PN measurement was accepted as a supplement to gravimetric PM mass measurement

Particulate Mass or Particle Number? India / China etc Signatories of UN-ECE EURO 5/6 PM and PN Limits (2011) PM Mass Only PM / PN Methods defined

Particulate Mass or Particle Number? India / China etc Signatories of UN-ECE PM Mass Only EURO 5/6 6*10 11 p/km equivalent to < 1mg/km PM / PN Methods defined EURO 5/6 PM and PN Limits (2011)

EPA Mandated Legislation Process

EPA Mandated Legislation Process Little historical epidemiological data on atmospheric PN and its effects on health at the present time so no limits on which to base sources of PN emission limits (unlike PM mass) PM Mass at 1 mg/mile is difficult to measure reliably with sufficient accuracy and precision California Air Resources Board will consider a PN alternative to PM mass during a Mid Term Review on measurement methods

EURO 5/6 PN Limit Defined From Vehicle Data PN limit defined to enforce the use of high efficiency (wall-end) diesel particulate filters

EURO VI HD PN Limit From Engine Data Similar process was applied to HD Onroad PN legislative emission limits Proposed NRMM Stage V of 1 * 10 12 P/kWhr adopted from Switzerland regulation Number includes PN from DPF regeneration. (not as Light Duty currently)

Why Solid Particles? Source : D.Kittelson

Why Solid Particles? Source : D.Kittelson Nuclei mode volatile particle number depends on a variety of conditions and measurement parameters and are not reliably reproducible Unlike solid (non-volatile particles) which predominate above 23nm for diesel vehicles

Light Duty : PMP Method for Solid PN from CVS

Heavy Duty PN Sampling from HD CVS No technical issues associated with PN sampling from CVS systems Unfortunately, fewer HD CVS systems are in use for HD engine emission testing

HD Engine PN Sampling from PM Mini-Tunnel Measuring PN from PM minidilution tunnels (partial exhaust flow dilution) can cause problems - sampling PN removes PM mass and so it must be corrected for PN sample flow - PN sample flow can affect the fast dynamic control of dilution ratio (even though correction is applied for the PN sample flowrate) - Is it essential to measure PN from the PM dilution system? As PN measurement is being applied to NRMM in 2019, this issue is under review

HD Engine PN Sampling From Exhaust Already used for PN R&D purposes PMP Working Group now working to compare direct measurement of PN from exhaust with the legislative prescribed measurement of PN from diluted exhaust As PN measurement systems have real time CPC detectors with a similar response time to gas analysers, the method should be applicable If successful and legislation is updated, would simplify Type Approval for PN and PM Mass This method is also the basis for Portable PN Measurement Systems (PN-PEMS) required for RDE for LD vehicles (and potentially In Service Conformity for HD vehicles)

EU Call for PN-PEMS Systems for RDE

HORIBA Prototype PN-PEMS System Combined approach of TSI / HORIBA for PN-PEMS system using a portable type CPC and miniature dilution / conditioning Good performance in the JRC testing programs incl good correlation to Laboratory PMP systems Participated in the Inter-Laboratory Correlation Exercise (round robin) organised by the JRC on a GDI vehicle The PN-PEMS system is now being proposed for ISC on HD engines used in On-Road vehicles (JRC program started 15/11/2015) If successful, then PN also for NRMM In Service Conformity could be possible On Board Capable ~ 15 kg, ~ 150W power

HORIBA Production OBS-ONE-PN Module Detail design modified and improved following the results and experience from the Inter Laboratory Correlation Exercise and other industry validation programs

PN-PEMS For RDE Latest Status Latest draft PN-PEMS specification close to finalisation (v7c) Key open issue is the uncertainty of the PN-PEMS instrument (CF factor = 1.0 +??) No additonal allowance for the vehicle PN emissions under real world driving conditions (or for market fuel) Expected to be discussed at next PEMS for RDE meeting Feb 29 th? Data from PN-PEMS Inter Laboratory Exercise under analysis Draft report to be issued by end of February Results summarised as being very satisfactory CPC detector more sensitive to PN concentration and less sensitive to PN size than Diffusion Charger detector Particle size changes on GDI from cold start / hot operation / full load etc Better correlation of CPC based PN-PEMS for HD Vehicle PN measurement No problems related to the CPC operation on board vehicle Final legislation proposal by end of March to be included in RDE 3 rd package submission

PMP WG Activities for PN > 10 nm Measurement of sub 23 nm solid particles has been discussed Reports of significant sub-23nm particles from HCCI (low temperature combustion) Metal oxide particles from lube DPF coatings can also release sub 23 nm precious metal particles JRC said that > 50 % of solid particles from PFI is < 23 nm Significant technical problems in calibration / measurement due to higher losses would need to be solved Possibility to require measurement of solid particles < 23 nm would be considered in the future should the vehicle powertrain technology require it PMP WG has reviewed the practical implications of sub 23 nm solid particle measurement down to 10 nm Non-Volatile Particle Number (nvpn) emissions from aircraft engines are already defined for > 10 nm (method SAE AIR6241)

Modified PMP System for PN < 23 nm Evaporator Tube was replaced by Hot Catalytic Stripper Active oxidation of volatile HCs and adsorption of sulphate CPC with D 50 below 23 nm is applied Commercially available instruments are available Design of sampling system to reduce losses of small particles (higher losses at 10 nm than 23 nm) Particle Transfer Tube VPR D 50 : 23 nm CPC-100 PNC D 50 : 4 nm 3775 PNC Short to reduce losses PND1 (191 ºC) To suppress the formation of volatile particles Hot Catalytic Stripper (350 ºC) For removal of volatile particle species and no artefact particle residue or formation PND2 (Room temp.) To minimize particle loss and re-nucleation SAE 2014-01-1604

EU Call H2020-GV-02-2016 for PN > 10 nm New generation of non-hybrid engines based on existing engine technologies (short term developments): proposals will address the optimal combination of innovative engine and robust after-treatment technologies as well as modelling and testing to improve the design and control capability. Special attention should be given to the assessment and reduction of particle emissions below 23 nm, particularly for direct injection gasoline and diesel engines. Future combustion engines for electrified powertrains (longer term developments): new combustion processes, sensing, control and after treatment systems, supported by advanced modelling technologies where needed to allow these engines to meet future ambitious energy and emission targets simultaneously. Special attention should be given to the assessment and reduction of particle emissions below 23 nm, particularly for direct injection gasoline and diesel engines. Development (based on current direct injection engines) of the related measurement procedures down to 10nm, providing a contribution to future regulation on particle emissions, in particular in real driving conditions. HORIBA contributed to a Consortium Proposal to meet the call....

PM in Europe Source : REBRAKE submission to PMP WG About 50% of traffic related air pollution comes from abrasion (brakes etc.) EURO 5/6 : < 1 mg/km Brakes / Tyres (urban) : ~ 3 mg/km 2011 HORIBA, Ltd. All rights reserved.

Research into Brake Particle Emissions Measurement of brake particle emissions on brake test dynamometer systems - Complete collection of brake dust plume without affecting brake operation - Adapting standard brake test cycles Variety of brake emission measurement parameters can be measured - PN (down to 23 or 10 nm) - Particle Size - Particle Composition - Particle Mass etc

Brake Dust Collectors In Future?

Summary Particle Number (PN) measurement is expanding More exhaust emissions applications (LD, HD, NRMM) Into potentially more countries (via GTR 4, GTR 11 and GTR 15 - WLTP) On-Board PN measurement for Real World Vehicle Emissions (RDE, ISC, Surveillance etc) is now a practical technology The PN counting size range may be extended in the future To cope with new combustion technologies, engine or after-treatments that might produce more particles smaller than 23 nm 10 nm is a reasonable compromise between particle size and ease of measurement (though still a significant challenge) PN is also being applied to non-engine related applications such as brakes and tyres...

Thank you and any questions? les.hill@horiba.com