37TH PMP MEETING

Institute for Energy and Transport Joint Research Centre

B. Giechaskiel, G. Martini

7 Oct 2015

PMP meetings

• 2014-04-03: PMP 30th

• 2014-05-12: PMP 31st telco• 2014-07-14: PMP 32nd telco• 2014-09-30: PMP 33rd • 2015-01-08: PMP 34th (Geneva summary)• 2015-03-04: PMP 35th • 2015-05-11: PMP 36th telco• 2015-10-07: PMP 37th

NRMM

• Presentation of potential issues related to the measurement of PN (30th)

• Guidance for PN testing (31st)

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 (30th) • Presentation of key areas (33rd)• Questionnaire sent for optimizing procedures and

minimizing areas of future investigation• Participants presentations• Summary of first replies (35th)

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 CE23nm>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, d50%=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/cm3, monodisperse 30 nm, mass 0.15 μg/m3).

• Polydisperse aerosol with GMD of 120 nm was also easily passed (mass 1.5 mg/m3).

System PMP PMP (CS)

CS + CPC

30 nm (mono), 10^4 p/cm3, 0.15 mg/m3 100% 100% 100%

120 nm (poly), 10^6 p/cm3, 1.5 mg/m3 100% 100% 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 (30th)

There are particles <23nm

• Experimental investigation at JRC (30th – 32nd +)There are particles <23nmSometimes 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 (30th).• Experimental investigation at JRC

Artifacts were confirmedExisting systems with small modification can measure below 23nm (from 10 nm)Below 10 nm the measurements will have high uncertaintyFrom 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)

Catalytic Stripper (CS) Requirements (under evaluation)* Description Oxidation, sulfur trap

Residence time s 0.25-0.4s

Operation temperature °C 350°C

PCRF ratio 15 nm to 100 nm %, how tested, material <2

PCRF ratio 30 nm to 100 nm %, how tested, material <1.3

PCRF ratio 50 nm to 100 nm %, how tested, material <1.1

Penetration 100 nm how tested, material >70%** Oxidation efficiency (gas) Gas, efficiency 99% with propane** Oxidation efficiency (particles) 30 nm Tetracontane particles 99.9% with concentration >50.000 p/cm3

*** Sulfur removal efficiency (gas) 5 ppm SO2 or SO3 99.9% with concentration >5 ppm SO2 or SO3

**** Sulfur removal efficiency (gas) >15 nm H2SO4 particles 99.9% with concentration >50.000 p/cm3

***** Sulfur capacity (gas) with 5 ppm SO2, total s stored >5 mg****** Sulfur capacity (particles) with 5 ppm SO2 >2.5 mg

total S stored before particle formation

* Tests have to be confirmed with for CS technologies with and without sulfur trap** Carrier gas: air to ensure enough oxygen for the CS*** No suggestion yet: Difficult test without saturating the CS**** H2SO4 formation needs suggestions (method, humidity)***** 5 ppm SO2 test means 2 weeks testing-->100ppm alternative. This total capacity, particles are formed earlier****** Note: 2.5 mg correspond to 90 h of operation for the CS (assuming 10 ppm sulfur fuel, 2500 ppm sulfur lubricant)

Existing CS specificationsCatalytic Stripper (CS) AVL Catalytic Instr.

Description Oxidation, sulfur trap Oxidation

Residence time 0.25 s 0.25 s

Operation temperature 350°C 375°C

PCRF ratio 15 nm to 100 nm <2 <2

PCRF ratio 30 nm to 100 nm <1.3 <1.3

PCRF ratio 50 nm to 100 nm <1.1 <1.1

Penetration 100 nm >70% >70%

Oxidation efficiency (gas) >99% with decane >99% with propane

Oxidation efficiency (particles) >99.9%, C40 >50000 p/cm3 >99.9%, C40 >50000 p/cm3

Sulfur removal efficiency (gas) - -

Sulfur removal efficiency (gas) - -

Sulfur capacity (gas) >6 mg -

Sulfur capacity (particles) >2.5 mg -

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

PCRF 30,50,100 30,50,100 15,30,50,100GMD GSD PMP 23nm PMP 10nm PMP 10nm

10 1.3 0% 22% 26%20 1.4 30% 69% 81%30 1.6 62% 85% 100%40 1.7 78% 93% 110%50 1.8 88% 98% 116%60 1.8 95% 102% 120%70 1.9 98% 104% 123%80 1.9 102% 106% 125%90 2 104% 107% 127%

10 + 50 1.3 + 1.8 44% 60% 71%

Regeneration

• Presentation of potential issues related to the measurement of PN during regeneration (30th)

• Summary of potential areas of investigation (30th)• Euro 6 vehicles, robustness of PMP, emission levels

• Proposal of experimental plan at JRC (31st)• WLTP input if regeneration at the end of the test• Preliminary tests at JRC confirm robustness of PMP

• Robustness of PMP 10 nm (35th)

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 (SO2-SO3 conversion)

• Regeneration: Robustness of PMP systems down to 10 nm