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Particulate matter (PM) emission of non-road diesel engines is more and more stringently restricted by US, EU, Japan, etc. In order to achieve these emission regulations, diesel particulate filter (DPF) system is applied. However DPF system requires extra fuel consumption in order to burn accumulated particles. Furthermore, since it is difficult to install large DPF systems in limited packaging space of non-road applications, compact DPF system is desirable. Reducing soot emission with engine technology is effective for reducing PM emission, which results in reducing extra fuel consumption and downsizing or removing of DPF system. Soot emission level mainly depends on excess air ratio (EAR), and can be reduced by keeping EAR high (lean combustion). However, lean combustion under the limited amount of air and maximum in-cylinder pressure requires decrease in fuel injection quantity, and yields decrease in engine power.

The main objective of the present paper is the application of a detailed kinetic model to study diesel combustion in an optical accessible engine equipped with a common rail injection system. Three different injection schedules made of one to three consecutive injections are considered from both the numerical and the experimental point of view. The numerical model is assessed in such a way to assure its portability with respect to changing injection strategies. The employed detailed kinetic mechanism consists of 305 reactions involving 70 species and is included in the KIVA-3V code. The considered fuel has the liquid phase properties of the diesel oil, the vapor phase properties of C14H28. It is subsequently decomposed into n-heptane and toluene. The chemical solver is based on the use of the reference species technique and on the Partially Stirred Reactor (PaSR) hypothesis. These allow maintaining the computational cost within acceptable limits.