Prechamber and main chamber insulation effects on the performance of an IDI diesel engine coupled to power turbine

Abstract

A thermodynamic simulation of a diesel engine cycle presented in this study which serves the purpose to examine the effects of insulating the main chamber and the prechamber, on the performance characteristics of a naturally aspirated, IDI (indirect injection), diesel engine. The insulation of both combustion chambers is taken into account by the corresponding rise of wall temperature, since this is the final result of insulation useful for the present study. It is found that an improvement of efficiency is achieved when insulating only the prechamber. However, when insulating the main chamber, a serious decrease of engine volumetric efficiency is observed which leads to a decrease of efficiency. The improvement in efficiency rises when a power turbine is incorporated at the engine exhaust, converting (recovering) partially the high energy of exhaust gases to mechanical power, which is transferred to the engine crankshaft via a gearbox (turbocompounding).