Comparison of PM exhaust emissions measured at a chassis dynamometer and on-road chasing Rainer Vogt, Volker Scheer, Roberto Casati Ford Forschungszentrum Aachen GmbH Barouch Giechaskiel, Zissis Samaras LAT, Aristotle University Thessaloniki

2 Overview Objectives of the study On-road chasing method Results of on-road chasing Laboratory experimental setup Results of chassis dyno work, comparison of instruments Comparison of lab and chasing Conclusions

3 Objectives To measure the PM emissions of the VW TDI by chasing the exhaust plume with the Ford Mobile Laboratory (FML) at three constant speeds and fixed distance on a test trace To measure the PM emissions of the VW TDI with the PARTICULATES dilution system at the FFA chassis dynamometer at the same constant speeds and during the NEDC To compare the results obtained with the PARTICULATES dilution system with real-world dilution measured during chasing the exhaust plume with a special focus on nucleation particles

4 On-road chasing of exhaust plume Test vehicle: VW Golf TDI 1.9 l speed, fuel consumption EN590 diesel (280 ppm S) Ford Mobile Lab: SMPS, CPC, NOx, CO 2 T and RH Test track: high speed oval, 4 km/lap 14 m distance: 0.4 s (120 km h -1 ) 1 s (50 km h -1 )

5 In-let for on-road sampling inlet: 4 mm (15 cm) transfer line: 10.3 mm (420 cm) total residence: 1.4 s

6 Constant speed tests T= 3-6 °C, RH= % (February 2003) 10 min warm-up at 120 km h -1 8 min at 120, 100, 50 km h -1

7 Geometric Mean diameter

8 Speed ramp tests

9

10 Comparison: Lab & On-road chasing 50km h -1 PFSS: PDR: 12.5 DT: 32°C LR

11 Laboratory experimental setup Results of chassis dyno work comparison of instruments - Makis part -

12 Comparison: Lab & On-road chasing 100km h -1

13 Comparison: Lab & On-road chasing 120km h -1

14 Conclusions (1) The PARTICULATES system is suitable to study the influence of the dilution parameters on nucleation Longer residence time favours the growth of the nucleation particles and shifts the nucleation mode to larger diameters Lower dilution air temperature enhances the formation of nucleation particles, with increased number and a distinct mode is formed at lower speed. Chasing and lab experiments show that nucleation is not stable in a time scale of several minutes; dependent on vehicle history as shown in speed ramp tests

15 Conclusions (2) The particle size distributions (only soot mode present) measured during chasing at 50 km/h were in very good agreement with dynamometer measurements At about 100 km/h nucleation particles occur during the chasing experiment. The occurrence and in general the emission rate of these particles can be reproduced with the PARTICULATES system, if the dilution parameters are chosen in order to match the ambient conditions. At 120 km/h a strong nucleation mode is observed in the exhaust plume. While the PARTICULATES system is capable to reproduce the soot mode very well, it shows a nucleation mode, which is somewhat lower in particle number, but larger in diameter.

16 - Back-up -

km h -1 simulated % grade Effect of chassis load

18 Effect of chassis load 120 km h -1 simulated % grade