Modelling of turbocharged diesel engines in transient operation. Part 2: Wave action models for calculating the transient operation in a high speed direct injection engine

Abstract

Part 1 of this paper analysed the physical phenomena involved in the transient operation of turbocharged diesel engines, together with the principles of diesel combustion characterization during the transient process. This second part describes a calculation model developed to predict engine transient performance based on an existing wave action code. Relevant improvements introduced are combustion process simulation and modelling of heat transfer, variable geometry turbine behaviour and mechanical losses. Experimental load transient tests with a high speed direct injection engine have been performed, with the aim of assessing the model accuracy. The main evaluation parameters were instantaneous variation during turbocharger rotating speed transient, boost pressure, air mass flow, injected fuel and exhaust pressures.