UNECE WLTP Durability Task Force Status of experimental work at JRC A. Zardini, B. Giechaskiel, G. Martini European Commission - Joint Research Centre Directorate for Energy, Transport and Climate Sustainable Transport Unit UNECE-DTF phone conference June 20, 2017 Contact: alessandro.zardini@ec.europa.eu
Objective Comparison of the thermal load to after-treatment devices of passenger cars driven over different driving cycles (SRC and WLTC) Since the AMA cycle is considered obsolete, the focus will be on the SRC and on the WLTC (World-wide harmonized Lightduty Test Cycle)
Test protocol Test vehicles (planned) PFI gasoline engines with TWC GDI stoichiometric and, if available, lean-burn GFI with TWC, Lean NOx Trap (LNT) and GPF Diesel engines with different after-treatment devices: DPF+LNT, DPF+SCR, DPF+LNT+SCR Driving cycles SRC and WLTC Fuel Diesel B7 and petrol E10 Preconditioning 3x EUDC using the reference fuel. Or for PI engines only: 1x UDC followed by 2x EUDC. Test sequence Day 1: Preconditioning Gasoline vehicle: Day 2: 1 WLTC cold +2WLTC hot Day 3: 1 SRC cold +1SRC hot Diesel vehicle: Day 2 to day x: 1 WLTC cold +2WLTC hot +nwltc hot (until regeneration takes place) Day (x+1) to z (end): 1 SRC cold +1SRC hot +nsrc hot (until regeneration takes place)
Data handling Equivalent ageing time for reference temperature R = thermal reactivity of the pollution control device. TWC: 17 500 Diesel oxidation catalyst (DOC): 18 050 Catalysed DPF: 18 050 SCR or ammonia oxidation catalyst (AMOX) based on iron-zeolite (Fe-Z): 5 175 SCR copper-zeolite (Cu-Z): 11 550 SCR Vanadium (V): 5 175 LNT (lean-nox trap): 18 050 T r = reference temperature, in K. T i bin = mid-point temperature, in Kelvin, of the temperature bin i to which the pollution control device is exposed during the data collection phase, registered in the temperature histogram. t i bin = the time, in hours, corresponding to the temperature Ti bin adjusted to a full useful life basis. t i e = the equivalent ageing time in hours needed to achieve, by exposing the pollution control device at the temperature T r, the same amount of ageing as the one that would result from exposure of the pollution control device at the temperature T i bin during the time ti bin. i = bin number, where 1 is number for the bin with the lowest temperature n = the i-value for the bin with the highest temperature.
Data handling Total equivalent ageing time (AT) AT is the total equivalent ageing time, in hours, needed to achieve, by exposing the pollution control device at the temperature T r,thesame amount of ageing as the one that would result from exposure of the pollution control device, over its useful life, to the temperature T i bin during the time t i bin of each one of the i bins.
Test Cell The vehicle was tested in the facility VELA 1 of the Vehicles Emissions Test Laboratories, European Commission - Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, Ispra (VA), Italy Basic technical specification: Climatized test cell: -7 C or 25 C Dyno: Zoellner 48, 0-200 km/h Inertia: 350-2500 kg Constant Volume Sampler: 1.5-11.2 m 3 /min Analyzers: AVL i60 2 nd series / 7372
Installation Installation of pre-cat thermocouple (red circle) close to engine-out lambda sensor (blue circle)
Vehicles & Tests Vehicle Technical specifications Vehicle Make Model Code Year EURO Fuel Displacement [cm3] Cylinders Power [kw] Transmission Gears Mileage [km] Injection After Treatment 1 FIAT Panda FT059 2016 EURO 6 E5 1242 4 51 MT 5 2500 PFI TWC 2 Summary of tests with relevant parameters Test Code Veh Cycle Cold start 1 170407_01 1 NEDC Y Notes Comparison Vela2 T pre T post T tailpipe T oil Y Y Y Y 2 170412_02 1 WLTC Y Pre-test Y Y Y Y 3 170418_02 1 WLTC Y 1st cold Y Y Y Y 4 170418_03 1 WLTC N 2nd hot Y Y Y Y 5 170418_04 1 WLTC N 3rd hot Y Y Y Y 6 170419_01 1 SRC Y 1st cold Y Y Y Y 7 170419_02 1 SRC N 2nd hot Y Y Y Y
Test example - signals WLTC cycle Test 3, Cold start, Distance: 23.19 km, Raw tailpipe sampling (T=190 C), T precat, postcat, tailpipe, oil. T profiles T range (hot): 400-800 C
Test example T distribution WLTC cycle Test 3, cold start Vela1_170418_WLTP_02 Speed [km/h] 0 20 40 60 80 100 120 real scheduled Temperature [C] 0 200 400 600 800 Pre Cat Post Cat TP Oil Sampling frequency Bin size Useful life 1 Hz 10 deg 160000 km 0 500 1000 1500 Time [s] 0 500 1000 1500 Time [s] Frequency 0 20 40 60 80 100 Cum. Frequency 0 500 1000 1500 Equivalent ageing time for each temperature bin extrapolated to useful life 0 200 400 600 800 T Pre Cat [C] 0 200 400 600 800 T Pre Cat [C] Frequency 0 20 40 60 80 100 Cum. Frequency 0 500 1000 1500 Total equivalent ageing time 0 200 400 600 800 T Post Cat [C] 0 200 400 600 800 T Post Cat [C]
Summary Total equivalent ageing time Reference T for Arrhenius: 400, 700, 800 C Thermal Reactivity for 3-way cat, R = 17 500 Test No. Vehicle Fuel Technology Cycle Cold start Comment T oil start AT-pre-400 AT-pre-700 AT-pre-800 AT-post-400 AT-post-700 AT-post-800 [C] [h] [h] [h] [h] [h] [h] 3 1 G TWC WLTC Y 1st cold 24.5 3.68E+06 1215.4 227.5 7.21E+06 2383.2 446.1 4 1 G TWC WLTC N 2nd hot 99.0 3.91E+06 1292.5 241.9 7.41E+06 2452.0 459.0 5 1 G TWC WLTC N 3rd hot 100.8 3.22E+06 1065.9 199.5 7.03E+06 2323.3 434.9 6 1 G TWC SRC Y 1st cold 22.6 3.72E+06 1229.1 230.1 7.14E+06 2360.8 441.9 7 1 G TWC SRC N 2nd hot 95.5 4.23E+06 1397.9 261.7 8.15E+06 2696.2 504.7
Summary single tests Hours 0 200 400 600 800 Total equivalent ageing time Reference temperature, Tr : 800 C Thermal reactivity for 3-way cat, R = 17 500 different driver AT-pre-800.h AT-post-800.h WLTC Cold WLTC Hot WLTC Hot SRC Cold SRC Hot Test
Summary combined tests Hours 0 100 200 300 400 500 600 AT-pre-800 AT-post-800 comparison WLTC Cold WLTC Hot WLTC Hot SRC Cold SRC Hot 2xWLTC C+H 2xWLTC H+H Test3 Test4 Test5 Test Test3+Test4 Test4+Test5
Discussion 1. Driving style (drivers) Strong effect on Temperature even when speed traces are the same 2. SRC Driving instructions To be implemented 3. SRC Gear shift strategy on-going at JRC 2. and 3. would improve temperature profiles reproducibility
Example of effect on Temperature Test 4 (hot WLTP) VS Test 5 (hot WLTP): speed and temperature profiles Speed Temperature WLTP hot WLTP hot Speed [km/h] 0 40 80 120 Test4 170418_03 170418_04 Test5 0 500 1000 1500 Delta -8-4 0 4 Delta -250-100 0 100 T Pre Cat [C] 300 500 700 Test4 170418_03 170418_04 Test5 0 500 1000 1500 Time [s] Time [s] 0 500 1000 1500 0 500 1000 1500 Time [s] Time [s] Speed traces are similar T profiles are NOT similar
Thanks for your attention