ACEA Programme on the Emissions of Fine Particulates from Passenger Cars(2) Part 2: Effect of Sampling Conditions and Fuel Sulphur Content on the Particle Emission

The results of an investigation of the influence of the sulphur fuel content and different dilution techniques on fine particulate emissions are reported in this paper. Fuels with two different sulphur contents (<10 ppm and approx. 200 ppm) were used for a Diesel and a gasoline vehicle in order to compare four different dilution procedures. These comprised the standard CVS tunnel and two pre-heated and one non-heated direct dilution systems. Various particulate measurement instruments were employed simultaneously, including SMPS, CPC, and ELPI for number and size, the standard gravimetric filter method for mass. In addition, Soxhlet extraction for chemical composition was carried out.

A higher fuel sulphur content was found to clearly increase particulate emissions from the Diesel and the gasoline vehicle for higher load. The increase in emissions was due to the contribution of condensed material and most of it could be clearly brought into relation with to sulphur compounds. The comparison between the different dilution systems showed a good agreement for the accumulation mode in number and size. Drastic differences were observed concerning the nucleation mode for the tests with high sulphur fuel. Whereas the pre-heated dilution systems do not show a nucleation at all, the total number concentration was increased up to an order of magnitude for the non-heated systems.