Technologies for low emission light duty powertrains HORIZON 2020 Call: H2020-GV-2016-2017 Technologies for low emission light duty powertrains Action: “Measuring automotive exhaust particles down to 10 nanometres – DownToTen” 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

In collaboration with: Project Partners In collaboration with: The University of California at Riverside, National Traffic Safety and Environmental Lab (Japan) and National Metrology Institute (Japan) 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Aim of the project To propose a robust approach for the measurement of particles from about 10 nm both for PMP and RDE, complementing and building upon regulation development activities and addressing topics not tackled so far The objective is a PN-Portable Emission Measurement System (PEMS) demonstrator with high efficiency in determining PN emissions of current and future engine technologies in the real world 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Why measure sub-23nm Particle Number? <23nm particles detected on regulatory cycles; levels relatively low (except 2T!) – but are there unexplored cases where levels are high? Sub-23 nm fraction of solid particles estimated by differences between 10 nm & 23 nm CPCs Loss corrected (between x1.7 and x2) Vertical dashed line 6x1011 p/km limit for particles >23 nm Other line indicates 6x1011 p/km limit for particles >10 nm All mopeds were 2-stroke unless otherwise specified in the figure B. Giechaskiel, J. Vanhanen, M. Väkevä & G. Martini (2017): Investigation of vehicle exhaust sub-23 nm particle emissions, Aerosol Science and Technology 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Some interesting results: <23nm non-volatile PN from diesel fuel cuts and >23nm particles derived from urea-SCR Driving events and ECT can produce <23nm particles: further investigation required Light-duty (1.4L, 66kW) turbocharged diesel engine Amanatidis et al. (2017) J Aerosol Sci Amanatidis et al. (2014) ES&T 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Questions to be answered within the new size range What is the number fraction of exhaust particles below 23 nm? What is the specific chemistry of the particles? How to define the particle species: accumulation – nucleation mode, volatile – non-volatile, solid –liquid, Black Carbon – Elemental Carbon (BC-EC) What fraction of exhaust particles corresponds to which species? Which is the appropriate exhaust particle cut size? How potentially un-regulated particles are linked to secondary aerosol formation How to robustly correlate raw exhaust sampling suitable for both RDE engine development with dilution methods and sampling approaches employed during engine and vehicle type approval? 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Exhaust emission related particle types Manifold out (ms) … Tailpipe out/dilution (s) … Atmosphere (h) Time lag? 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

DownToTen structure and WP interaction 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Synthesis and evaluation of testing results, incl. metrology (WP5) Concepts and approach Equipment and sampling set-up (WP2 & WP3) Modelling particle transformation (tailpipe-out to the inlet of the measurement equipment) (WP3) Synthesis and evaluation of testing results, incl. metrology (WP5) Testing (emphasis on technologies that will be developed in the parallel projects (WP4) 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Exhaust aftertreatment Fuels Cycles Source of the test vehicles Vehicle class Engines Exhaust aftertreatment Fuels Cycles Source of the test vehicles Passenger cars GDI & PFI 3WC with and without GPF Reference Petrol and biofuel admixtures NEDC, WLTC, 3 RDE cycles; real PEMS trips uPGrAdE, PaREGEn SI-Hybrid A hybrid from GV-2-2016 Diesel SCR and/ or NSC with DPF Reference diesel and biofuel admixtures DiePeR CI-Hybrid SCR/NSC with DPF CNG Different qualities GasON HDV SCR and DPF WHVC, standard CO2-vehicle test cycles; PEMS trips To be decided Not decided yet 2-wheelers >500ccm 3WC WMTC, RDE cycles, PEMS test for >500ccm Suggestions from the German programme 50ccm   AVL Research Networking Day 2017

Overview of key project results WP Exploitable knowledge Exploitable product(s) or measure(s) Sector(s) of application Timetable for commercial use Owner & other partners involved WP2 Proposal for system to generate laboratory-grade exhaust-type of aerosol Device and method to generate aerosol (demonstrator in month 14) Calibration institutes, users of aerosol instruments 2020 TUT, TUM Instrument benchmarking below 23 nm Knowledge on instrument performance Exhaust aerosol measurement labs Not relevant TUT, AVL, LAT/AUTh, RICARDO WP3 Understanding formation, properties and characteristics of PN <23 nm PN <23 nm definition for regulatory purposes Standardization and regulatory bodies 2018 Entire consortium PN <23 nm sampling configuration for laboratory testing and PEMS Demonstrator (in month 17) PN <23 nm measurement configuration Instrumentation to be proposed WP4 DownToTen PN PEMS demonstrator unit Device and Test protocol (demonstrator in month 22) Exhaust aerosol measurement labs, regulatory authorities TUG, AVL, LAT/AUTh, RICARDO, TUT Evaluation procedures for RDE particle number Software code and method (demonstrator in month 32) 2019 TUG, AVL, LAT/AUTh, RICARDO, JRC WP5 Emission performance of late and forthcoming vehicle types Emission factors to be used in models and estimates Air quality research, policy making LAT/AUTH, TUG, TUT, TUM Calibration procedures for measuring PN<23 nm Calibration test protocols TUT, TUG, TUM, JRC Modelling of exhaust particle processes from emission to dilution Simulation model Researchers, manufacturers 2021 LAT/AUTH, TUT Months 1 –Month 14 Currently at Month 14 Months 7 –Month 21 Currently at Month 14

Planned progress per work task, including milestones and deliverables Device and method to generate aerosol - November 2017 PN <23 nm sampling config. Feb. 2018 DownToTen PN PEMS demonstrator unit - July 2018 Evaluation procedures for RDE PN May 2019 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Progress in the first year of the project 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP2: Sampling setup for testing in the synthetic aerosol laboratory (1) A setup was designed to maximize the penetration of non-volatile particles below 23 nm, while avoiding the creation of gaseous artefacts Important factors like robustness against artefacts (re-nucleation, growth of sub-cut particles), losses of (solid) particles, storage/release effects of gas phase compounds are being assessed in detail 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP2: Testing in the synthetic aerosol laboratory Silver particle generation Nano DMA Sample treatment (CO2 addition, mixing) CPC, cut size 2.5 nm Continuous measurement of dilution ratios Upstream / Downstream measurements with same tube Sampling systems used in the tests: HPCE: hot porous tube cold ejector CPCE: cold porous tube cold ejector HECE: hot ejector cold ejector (plus) CS: Catalytic Stripper Tampere Technical University 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017 PMP Meeting March 2017

WP2: Identified losses with the 1st gen WP2: Identified losses with the 1st gen. system (silver particle tests at TUT) Temperature 350 ˚C Thermophoretic losses are mainly caused by cooling down the sample with an ejector diluter (ED). Use of PTD for cooling reduces thermophoretic losses to almost zero. The catalytic stripper (CS) is the dominant source of diffusional losses. They are reduced by downsizing the CS. 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP2 - Conclusions and recommendations Nonvolatile particle losses Identified loss issues with components Diffusion: mostly at the CS Thermophoresis: in prototype cold ED Possible solutions Cooling dilution with porous tube (minimize thermophoresis) Optimising the CS size Artefact formation The HPCE system appeared to be artefact free at 10 nm. However, HC content in real exhaust aerosol could cause particle growth into the measured range. The CS effectively reduced particle growth.  Secondary aerosol sampling The system can be used for secondary aerosol emission characterization by using a separate line after the first dilution stage Meeting on the Particle Measurements Projects (DownToTen, PEMS4Nano, SUREAL-23), Brussels. June 29, 2017

2 systems produced, more on the way… WP3: 2nd gen. DTT system to contain two porous tube diluters (PD1 & PD2) was built for chassis dynamometer testing purposes (TUG and Ricardo) 2 systems produced, more on the way… 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

APG WP3: Preliminary calibration investigations (AVL) Setup 4 nm Full flow (0.3 lpm) 4 nm Full flow (0.3 lpm) TSI 3775 APG CS@350C 85Kr 85Kr 85Kr TSI 3775 DMA 3081 DMA 3081 DTT TSI 3790 23 nm TSI 3792 10 nm Two configurations of the DTT system (2nd gen.) were tested: Porous diluter + CS AVL @ 350 C + Porous diluter + Ejector Porous diluter + CS AVL @ 350 C + Porous diluter 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: Preliminary calibration investigations (AVL) (2) PCRF (particle concentration reduction factor) results DTT system enables several configurations to achieve required dilution approach Particle losses are configuration dependent; but main influence is flow rate through CS Particle penetration is better than commercial 10nm system PCRF takes into account losses and dilution ratio 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: Further calibration investigations (Ricardo) (1) 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3:Further calibration investigations (Ricardo) (2) PCRF’s in line with expectations of PMP systems Penetration with ejector diluter ~15% less efficient than the commercial PMP systems Penetration efficiency is very similar for CS and ET, but evaporation tube performs slightly better when hot Tests without ejector diluter would be of interest 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: PCRF to PMP requirements + 15nm calibration (Ricardo) Calibration with CAST soot 15nm, 30nm, 50nm, 100nm monodisperse aerosol Normal system operating parameters as used from CVS (used without ejector) PTD1 350°C – CS1 350°C – PTD2 23°C 2 slpm sampled (2 x 1 slpm CPCs) 3 slpm drawn from CVS (mfc flows differ by 1splm) 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: PCRF Results (without ejector dilutor) (Ricardo) Results similar to AVL (w/o Ej) 100nm PCRF = 141.9 50nm PCRF = 147.0 30nm PCRF = 159.7 15nm PCRF = 230.0 Flow dilution = 140.2 (26dil +3) – (27dil +2) 29/3 * 29/2 = 140.2 Low losses >50nm Open question: how to apply PCRF correction including <23nm? 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Preliminary chassis dynamometer investigations (Ricardo) SPCS v DTT correlation with 23 nm PNC Average concentration data from cumulative transient tests, and sub-cycles Good linear agreement between DTT system and Horiba 2000SPCS above 1 #/cm3 (at the PNC) across wide concentration range Larger differences below this point DTT reports ~ 14% lower than SPCS No PCRF correction applied to this yet 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Regulatory emission cycles: NEDC, WLTC, JC08, US06 WP3: “Regulatory cycle testing” of diesel technologies and one gasoline vehicle (Ricardo) Regulatory emission cycles: NEDC, WLTC, JC08, US06 Several emissions control system variants on diesels Few tests show either > 23 nm or > 4(7) nm levels above 6x1011 #/km One GDI + TWC test just above limit value Highest emissions (but less than 10x limit) from test containing DPF regeneration Ki factor would reduce this to well below the limit Generally, non regenerating DPF tests < 2% of limit value < Euro 6c limit 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: Evaluation of the DTT system with real exhaust (AVL) Cycle-averaged ratios of particle number emission rates Cycle-average mean particle diameter measured with the EEPS The mean particle size of all diesel vehicles (66 to 81 nm) was consistently higher from that of the GDI counterparts (26 to 40 nm) In a first set of tests, the DTT system was connected on the CVS tunnel in parallel with an AVL Particle Counter (APC) plus CS and allowed for parallel measurement with a 10 and a 23 nm CPC. In addition a TSI Engine Exhaust Particle Counter (EEPS) was connected on the CVS tunnel, sampling downstream of a catalytic stripper (also operating at 350 C) and a subsequent cold dilution of 10:1. The EEPS allowed for a calculation of the cycle-average mean particle size of the emitter particles 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

WP3: Raw vs Dilute Particle Sampling Modelling (AUTh) AIM: To understand the relationship between the final quantification of raw-sampled “regulated particles” and dilute sampled ones Critical for fundamental understanding and determining influence of measurement approach on conformity factors Achieved via simulation and modelling Overall aim: to couple aerosol dynamics model with commercial CFD code CFD simulations: flow, mixing heat transfer Aerosol dynamics simulations will address porous tube dilution and aging / mixing stages 2-D and 3_D simulations will address inflow boundary conditions, including impacts of flow instabilities 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Basic CFD analysis of Porous Tube Dilutor (AUTh) Critical components will be identified, in which to perform CFD. For example, flow and mixing unsteady 3D CFD simulations are performed for the PTD and mixer shown below by TU Graz. Evaluate pressure fluctuation effects on dilution – no particle impacts assessed yet; work on-going 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Modeling delayed primary: aerosol formation in the exhaust (CFD model) (AUTh) Modelling of particle formation rates in exhaust requires determining the spatial profiles of temperature, humidity, vapours and particles. In work by TUT, an in-house model CFD-TUTEAM, was developed and applied to a PTD dilution system with FLUENT. 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Next steps in the project More engine exhaust aerosol tests for the system (dilute and raw) Functional pressure/temperature/dilution evaluations in laboratory Construct several DTT systems for partners to enable more parallel testing at the later stages of the project For certain identified vehicle technologies: dedicated campaign(s) for characterization of chemical composition, semi-volatile particle emissions, secondary aerosol formation… Investigate possible <23nm sampling artefacts in CVS-diluted and raw exhaust Targeting towards PN-PEMS demonstrator, RDE capable measurement system Implementation and verification of modal approach for homogeneous aerosol Particle Dynamics Coupling of implemented Particle Dynamics model with CFD code 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017

Any questions? 45th PMP Meeting, Joint Research Centre, Ispra, November 7-8, 2017