Combustion in a Direct Injection Diesel Engine with Increased Clearance Volume

The aim of the investigation was to analyse the effects of an increased clearance volume on the performance of a high-speed direct injection (DI) diesel engine, and to seek ways of ameliorating problems with combustion. Tests were carried out on a high-speed DI engine at the standard and at a lower compression ratio, and the problems with combustion were analysed. Modifications made to the fuel injection system and engine operating conditions at the lower compression ratio resulted in substantial improvements in power output and fuel economy. This investigation is relevant to DI diesel engines operating with variable compression ratio.