A Design Strategy for Volumetric Efficiency Improvement in a Multi-cylinder Stationary Diesel Engine and its Validity under Transient Engine Operation

Abstract

This paper proposes an approach to improve engine performance of volumetric efficiency of a multi cylinder diesel engine. A computer simulation model is used to compare volumetric efficiency with instantaneous values. A baseline engine model is first correlated with measured volumetric efficiency data to establish confidence in the engine model's predictions. A derivative of the baseline model with exhaust manifold, is then subjected to a transient expedition simulating typical, in-service, maximum rates of engine speed change. Instantaneous volumetric efficiency, calculated over discrete engine cycles forming the sequence, is then compared with its steady speed equivalent at the corresponding speed. It is shown that the engine volumetric efficiency responds almost quasi-steadily under transient operation thus justifying the assumption of correlation between steady speed and transient data. The computer model is used to demonstrate the basic gas dynamic phenomena graphically. The paper provides a good example of the application of computer simulation techniques in providing answers to real engineering questions. In particular, the value of a comprehensive analysis of fundamental physical phenomena characterizing engine mass flow is demonstrated.