IN-CYLINDER DIESEL PARTICLE CONCENTRATION MEASUREMENTS.

Although many studies of the particle emissions from diesel engines have been made, the mechanisms of particle formation and removal within these engine are not well understood. The particles present in the exhaust of a diesel engine result from a complex set of formation and removal processes. Although relatively little can be learned about these processes from exhaust measurements, diesel engine combustion models are routinely validated against exhaust measurements. Our understanding of diesel particles in general and our ability to test combustion models in particular would be greatly enhanced by in-cylinder particle concentration histories. This paper describes part of a long term study aimed at obtaining reliable in-cylinder particle measurements. It describes recent particle measurements made with an improved in-cylinder sampling system and describes a preliminary comparison of the measurements with particle concentration histories predicted with a stochastic combustion model.