The DETR/SMMT/CONCAWE Particulate Research Programme was designed to investigate the effects of vehicle/engine technology level, fuel specification and various operating conditions on emissions of particle mass, number and size. Results from the heavy duty part of the programme and details of the measuring protocols have already been published. This paper gives the results of the light duty study. This consisted of six vehicles and eight fuels covering gasoline, Diesel and LPG technologies.
These six vehicles represented Euro II (1996) and Euro III (2000) technologies. Diesel fuels included EN590 (1996), EN590 (2000), UK ultra low sulphur Diesel (UK ULSD) and Swedish Class I Diesel, while gasoline fuels comprised EN228 (1996), EN228 (1999) and UK ultra low sulphur gasoline (UK ULSG).
Particle mass measurements were undertaken via the regulated method while the mass weighted size distribution was determined with a Micro Orifice Uniform Deposit Impactor (MOUDI) covering a size range from <56nm to 10μm. Particle number measurements and number-size distributions were performed with a Scanning Mobility Particle Sizer (SMPS). In addition to the particulate mass, the other regulated emissions were measured on a mass basis. Chemical analysis of selected particulate samples was also performed.
This paper concludes that in general, when viewing conventional Diesel, gasoline direct injection (G-DI), multipoint injection gasoline (MPI) and particulate filter equipped Diesel vehicles (DPF) together, vehicle technology effects were observed to be larger than fuel effects for total particle number. Total particle number was sub-divided into nucleation mode particles (nominated in this study as particles <50nm) and accumulation mode particles (>50nm). Observations concerning the accumulation mode particle numbers reflect those made for particulate mass.
Overall, integrated particle number emissions levels were generally highest from the conventional Diesel technologies, lower from the gasoline direct injection and lowest from the MPI gasoline and DPF equipped Diesel vehicles. However, particle size distributions and mass emissions differed greatly. Some fuel effects were also identified in specific vehicle technologies, but these were relatively small.