1. Emissions testing with PEMS versus random laboratory driving cycles
- Preliminary results
Pierre Bonnel
Martin Weiss
Joint Research Centre (JRC)
IES - Institute for Environment and Sustainability
Ispra – Italy

2. JRC emissions testing
Euro 5 diesel vehicle (4 cylinders; 55 kW; 49.8 kW/t; start-stop; DPF; 108 g CO2/km)
PEMS emissions testing on three routes (rural-motorway; rural-urban; rural-uphill/downhill)
Laboratory emissions testing based on NEDC, Artemis, two fixed driving cycles and one random driving cycle

3. PEMS emissions testing
NOx CO

4. PEMS emissions testing
Averaging window NOx emissions: exceedance of the Euro 5 emissions limit (0.18 g/km) by all windows

5. PEMS emissions testing
Accuracy of PEMS is comparable to laboratory equipment (tailpipe emission measurements) - PEMS uncertainty NOx ± 4% of reading; CO2 ± 3% of reading - different calibration gases

6. Lab emissions testing
(i) speed trace urban driving in Rome (low-medium severity) (ii) speed trace urban driving in Rome s of the Artemis urban cycles + 2x128 s of the US06 cycle (medium-high severity) (iii) free cycle based in defined idling periods and constant speed points (1,200s; 15 km; 46 km/h)

7. Lab emissions testing
Cycles (i) and (ii): - easily implemented; standard gear-shifting procedure - prescribed speed trace - good drivability despite severe acceleration (>0.8 m/s2)

8. Lab emissions testing
Cycles (i) and (ii): - easily implemented; standard gear-shifting procedure - prescribed speed trace - good drivability despite severe acceleration (>0.8 m/s2)

9. Lab emissions testing
Cycle (iii): Free cycle

10. Lab emissions testing
Speed trace free-cycle

11. Lab emissions testing
Speed trace free-cycle

12. Lab emissions testing
Speed trace free-cycle

13. Lab emissions testing
Emissions random cycles

14. Conclusions
Test procedures: - PEMS accuracy comparable to laboratory equipment - Fixed speed traces easily implemented; quick cycle design; gear shift prescriptions taken from the NEDC - Drivability (acceleration ~ 0.8 m/s2) has not been an issue - Free-cycle: more challenging with respect to implementation and execution - Free-cycle: variability of speed traces is limited (variability is difficult to achieve; drivers are used to follow prescribed speed traces)

15. Thank you!

16. Overall CO2 emissions
Overview: CO2 emissions

17. Conclusions
Emissions: - on-road NOx emissions substantially exceed Euro 5 emissions limit - CO2 emissions slightly elevated; average tested emissions vary between g CO2/km