Effect of Compression Ratio on Petro-DEE Fuelled HCCI Engine

Abstract

In compression ignition engines, soot-NOx paradox is extremely challenging issue, which remains to be resolved. Homogeneous charge compression ignition is a new combustion concept that gives benefits such as diesel like efficiency and resolves the problem of high level of NOx and PM simultaneously. It gives very high rate of heat release which cannot be easily controlled. The present work deals with development of HCCI engine and experimental investigations on petrol fuelled with DEE as ignition enhancer under two different compression ratios. Homogeneous mixture preparation is the most critical part of the HCCI combustion concept. To achieve homogeneous mixture of fuel and air, diethyl ether was used due to its low evaporating temperature around 35^oC. The mixture was inducted through a nozzle into the intake manifold specially fabricated for the engine under consideration. Constant speed experiments were performed to observe behaviour of HCCI combustion. The engine’s load carrying capacity was controlled by regulating the fuel flow. It was observed that engine could run smoothly at lower loads but knocking was noticed at higher loads. Compared to neat diesel fuel operation, at the same power, concentration of NOx and smoke opacity were observed to be reduced by 80% and 93% respectively.