Abstract
With regard to their use in passenger cars, spark-ignition and diesel engines are currently involved in a technology competition.
Wheras the spark-ignition engine is boosting its efficiency towards that of a diesel engine, the diesel engine, in turn, is catching up with the spark-ignition engine in terms of power output and refinement.
In view of the forthcoming direct injection technology for spark-ignition engines the question arises as to the extent to which the diesel engine may be able to maintain its traditional advantage against this innovative generation of petrol engines.
This topic is covered in the following paper. The main differences in efficiency are established by means of thermodynamic analysis of the petrol and diesel engine combustion processes. The results show that as far as efficiency is concerned the direct-injection diesel engine is certain to maintain its lead against direct-injection spark-ignition engine in the future.