Results of the preliminary research phase 1 of the Swiss contribution to GRPE Particulate Measurement Program
Peugeot with SiC-Diesel particle filter (DPF) has much lower emissions of nanoparticles, than generally supposed until now. The usual SMPS measurements from the CVS dilution tunnel estimate the background concentrations in the CVS dilution air, which are about 40 times higher, than the concentrations of finest particles in the exhaust gas of the vehicle. This fact was stated at the Laboratory for Exhaust Gas Control of the University of Applied Sciences, Biel/CH during the measurements which contributed to the GRPE Particulate Measurement Program in charge of the FOEFL (Swiss Federal Office for Environment, Forests and Landscape - BUWAL) , , .
During the trials there was sampling at different points of the exhaust gas analyzing system, Fig. 1.
Figure 1. Sampling and measuring set-up for nanoparticulates on the chassis dynamometer
Beside the heating of the sampled gas probe the MD19 NanoMet minidiluter, Fig. 2, makes it possible to realize very high dilution ratios (until 3000) in one step and this enables the aerosol to be fit in the measuring system almost without changes. The dilution air of the minidiluter is absolutely filtered (< 0.2 part./cm3).
Figure 2. NanoMet minidiluter at the tailpipe
Due to the air filter of the CVS air inlet there are about 2 times lower particle count concentrations in the CVS air than in the ambient air, Fig. 3. This is represented in relationship to a modern diesel engine without DPF at a part load operating condition.
Figure 3. Integrated particle counts: ambient, CVS, non treated exhaust gas
With the particle filter (with Peugeot 607), Fig. 4, the particle counts measured in the CVS tunnel decrease with the increasing vehicle speed, because the exhaust gas flow increases. The particle count-concentration in the exhaust gas is about 18 times lower, than in the CVS dilution air. Due to that both gases change the roles: the CVS air is the emission source and the exhaust gas acts as the dilution air. The represented relationships could be confirmed thanks to the application of the NanoMet minidiluter.
Figure 4. Particle counts in the CVS tunnel and at tailpipe with the Peugeot 607 FAP
Dr. J. Czerwinski
Lab. for Exhaust Emission Control, University of Applied Sciences Biel-Bienne
Tel. 0041 32 321 64 26, Fax. 0041 32 321 59 34
Dr. M. Kasper
Matter Engineering AG
Tel. 0041 56 618 66 38, Fax. 0041 56 618 66 39