The modelling of an engine injector mechanism as a dynamic gain element and its application†

Abstract

The recent availability of extensive experimental results on the frequency response testing of a diesel engine has lead to an investigation of the influence of the injector mechanism on the dynamic behaviour. It is shown that this mechanism can be modelled as a dynamic gain element which, together with the authors' previously developed models for this type of engine, shows why difficulties were experienced in obtaining the frequency response plots. Additionally, the developed theory shows why diesel engines tend to exhibit unstable behaviour when lightly loaded.