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Procedures for the measurement of aromatic hydrocarbons in undiluted Diesel exhaust gases were developed and compared. In the first one, hydrocarbons are trapped on sorbents, then analysed by thermal desorption coupled to GC/FID. Eight monoaromatic hydrocarbons and eleven PAHs from two to four aromatic rings have been detected. The second procedure uses three media: a filter, a condenser and a resin cartridge. After extraction, samples are purified and analysed by GC/FID or by HPLC/Fluorescence. Fourteen PAHs of two to six aromatic rings have been thus quantified. The two procedures are in agreement for the common species measured. The procedure using the analysis by HPLC/Fluorescence is both more selective and more sensitive. It allows an estimate to be made of the influence of load and speed on PAH emissions.

An experimental study of diesel spray / wall interaction is conducted in a pressurized bomb using Phase Doppler Anemometer and high speed shadowgraphy. The instantaneous droplet sizes and velocities are measured in the impingement region, without combustion, in the plane located at 3 mm from the wall, for four wall temperatures 20, 200, 300 and 400 °C. A droplet wall interaction model has been developed and incorporated in the Kiva II code. The model accounts for droplet atomization and heat transfer. The computed spray penetration, the shape contour and the SMD are compared respectively to spray photographs and PDA measurements.