37 TH PMP MEETING Institute for Energy and Transport Joint Research Centre B. Giechaskiel, G. Martini 7 Oct 2015

PMP meetings : PMP 30 th : PMP 31 st telco : PMP 32 nd telco : PMP 33 rd : PMP 34 th (Geneva summary) : PMP 35 th : PMP 36 th telco : PMP 37 th

NRMM Presentation of potential issues related to the measurement of PN (30 th ) Guidance for PN testing (31 st )

Raw exhaust (tailpipe) sampling Is there a need to develop an additional option for PN measurement in the case of HD engines? Issues summarized by Ricardo Limited number of comments Program suggestion (presentation Ricardo)

Raw exhaust (tailpipe) sampling Experimental program Primary dilution Losses Volatile removal efficiency Pressure effects Time alignment JRC will wait for experimental data Limited number of tests from PN-PEMS for HD program

WLTP PM/PN definitons The term ‘particle’ is conventionally used for the matter being characterised (measured) in the airborne phase (suspended matter), and the term ‘particulate’ for the deposited matter. "Particle number emissions" (PN) means the total number of solid particles emitted from the vehicle exhaust quantified according to the dilution, sampling and measurement methods as specified in this gtr. "Particulate matter emissions" (PM) means the mass of any particulate material from the vehicle exhaust quantified according to the dilution, sampling and measurement methods as specified in this gtr;

Calibration of PN systems Review of open issues (30 th ) Presentation of key areas (33 rd ) Questionnaire sent for optimizing procedures and minimizing areas of future investigation Participants presentations Summary of first replies (35 th )

Calibration topics overview Is there a need? Based on PMP 33th presentation optimized calibration procedures can improve the differences between PN systems 7-12% PNC open issues VPR open issues Decision based on MINIMUM extra work Lower size of 10nm should be kept in mind

Participants presentations No presentations

PNC Reference PNC: ISO Slope: 0.9 to 1.1, residuals ±4% (from 10%) k factor: should be included (and reported) – to be confirmed Material: soot, emery oil -> TSI, AVL, JRC workshop ISO 27891: Should be adopted, with applic. notes Steepness criteria: needs addition of another size Drift: Monitored (as WLTP)

VPR Calibration PNC: calibrated, Require CE 23nm >90% One or two PNC method: Concerns with two PNCs method due to non linearity  Intercalibrated Stability: Decrease from 10% to 3% (5%?) Neutralizers: One Material: Stable Penetration and DF: Input needed Polydisperse validation: GMD 50nm, GSD 1.8 input? C40: Require air for generation, d 50% =10nm, higher initial concentration, add bigger size  to be investig

Volatile removal efficiency The legislative tetracontane tests were easily passed by all systems (concentration >10^4 p/cm 3, monodisperse 30 nm, mass 0.15 μg/m 3 ). Polydisperse aerosol with GMD of 120 nm was also easily passed (mass 1.5 mg/m 3 ). SystemPMPPMP (CS) CS + CPC 30 nm (mono), 10^4 p/cm 3, 0.15 mg/m 3 100% 120 nm (poly), 10^6 p/cm 3, 1.5 mg/m 3 100%

Volatile removal efficiency Atomized emery oil >100 nm polydisperse aerosol Residuals <10nm

Volatile removal efficiency Atomized emery oil >100 nm polydisperse aerosol Three CS were tested in different configurations

Volatile removal efficiency A 2-stroke moped emits >15 mg/m3 at cold start Summary of different combinations

Sub23nm measurements Is there a need? Literature review: Emission levels of sub23nm (30 th ) There are particles <23nm Experimental investigation at JRC (30 th – 32 nd +) There are particles <23nm Sometimes they are an artifact “Real particles” are on average 30-40% on average over a test cycle Monitoring of newer technologies goes on (at JRC)

Sub 23nm update (>10nm) 4 moped 7 motorcycles 7 diesel with DPF 2 diesel w/o DPF 13 GDIs (9 Euro 6) 9 PFIs (4 Euro 6) Typically 5-10 tests per vehicle

Sub23nm: Monitoring Tendency of higher ratio at lower concentrations DPF (no) No extremes -2s-wheelers

Sub23nm measurements Can we measure <23nm? Theoretical investigation: Feasibility of existing PN systems to measure <23nm (30 th ). Experimental investigation at JRC Artifacts were confirmed Existing systems with small modification can measure below 23nm (from 10 nm) Below 10 nm the measurements will have high uncertainty From 10 nm some areas need investigation like: -PCRF definition -Catalytic stripper -Specification of >10nm systems -New need of calibration procedures

Catalytic stripper: Losses Catalytic instruments (CS, no sulfur trap) + CPCs AVL (ET + CSst + CD) + EEPS AVL (HD + ET + CSst +CD) + CPCs PMP CPC = Condensation Particle Counter EEPS = Engine Exhaust Particle Sizer HD = Hot Dilution (150°C) ET = Evaporation Tube (300°C or 350°C) CS = (Hot) Catalytic stripper (st=sulfur trap) CD = Cold Dilution

Catalytic Stripper: PCRF PCRF (30, 50, 100) of total setup: approx. 1.4

VPR(PMP) vs CS Similar (normalized) penetration curves (incl. CPC)

Catalytic stripper: Measurements 3 moped 2 motorcycles 1 diesel w/o DPF 5 diesel with DPF 10 GDIs (7 Euro 6) 3 PFIs (1 Euro 6) Typically >5 tests per vehicle

Catalytic stripper: Results No difference between PMP_23nm and CS_23nm No differences between PMP_10nm and PMP/CS_10nm Small difference between PMP_10nm and CS_10nm due to the different counting efficiency of the CPC3010 at the CS_10nm

Catalytic stripper: Results Similar differences over the cycle Examples of cycles with cold start (two vehicles)

PMP vs PMP+CS (tailpipe) No differences observed for a GDI even with both instruments connected to the tailpipe (23nm)

Existing CS specifications Input for SO2 to SO3?

Sub 23nm: Error estimation Assumptions >23nm measurement correct Difference >10nm and >23nm are the 10-23nm Penetration of 15nm can give the mean losses in the 10-23nm region Thus the PCRF of 15nm is the extra correction need for the sub23nm measurement Thus the percentages presented have to be corrected with values of approximately 1.7

PCRF selection The mean 30,50,100nm PCRF could remain, although the 15,30,50,100nm PCRF is more accurate for smaller sizes

Regeneration Presentation of potential issues related to the measurement of PN during regeneration (30th) Summary of potential areas of investigation (30 th ) Euro 6 vehicles, robustness of PMP, emission levels Proposal of experimental plan at JRC (31 st ) WLTP input if regeneration at the end of the test Preliminary tests at JRC confirm robustness of PMP Robustness of PMP 10 nm (35 th )

Regeneration PMP 23 nm and PMP 10 nm robustness

Regeneration (Forced every 200km) Existence of sub23nm sometimes Could be desorption from tubes until CVS due to high T. Tailpipe measurements didn’t see this (subsequent test) Important: Robustness of PMP even at 10 nm.

Key conclusions Raw exhaust sampling for HD  Input to JRC is needed based on suggested program Calibration PMP: Open: Material for PNC, Volatile Removal efficiency  Next meeting Sub-23 nm: Percentages tend to increase compared to diesel. Not critical (except 2-s engines) Sub-23nm systems: Ready. Minor details missing for CS investigations (SO 2 -SO 3 conversion) Regeneration: Robustness of PMP systems down to 10 nm