Simulation of CI engine flow processes for prediction of performance and emissions with different fuels

Diesel-fuelled direct injection compression ignition engines yield high fuel conversion efficiency due to the use of high compression ratios and thus find their place in varied applications. However, tail pipe emissions of conventional diesel engines are a major source of high levels of oxides of nitrogen (NOx) and particulate matter. Owing to stringent emission legislation, manufactures and researchers are facing tough competition to make them eco-friendly. The present paper deals with a simulation of extensive numerical experiments carried out on a single-cylinder diesel engine by varying timing of inlet valve closing (25 degrees-55 degrees ABDC) and fuels; rapeseed methyl esters and diesel fuel. For this purpose, a zero-dimensional thermodynamics-based model in C++ was developed. The model takes into account the engine speed, fuel injection timing and equivalence ratio, temperature-dependent specific heat ratio and inlet valve close timing. The engine performance is evaluated in terms of thermal efficiency, in-cylinder pressure, heat release rate, and NO and soot emissions. It is observed that a significantly delayed closing of the inlet valve would result in loss of charge, and rapeseed methyl ester could be an attractive and viable alternative to petro-diesel fuel.