Diesel Engine Model with Multi-Model Correction of Intake Manifold Pressure

Abstract

A simulation model of a diesel engine is widely applied to evaluate the engine controller before a vehicle test because controller error can be observed by the engine model. For diesel engine modeling, an adiabatic model is commonly used to express intake manifold pressure because it is a powerful method to depict pressure dynamics. However, the adiabatic model is vulnerable to steady state error, as it neglects the heat exchange. In order to solve this issue, we propose a multi-model correction algorithm for the diesel engine model. The proposed diesel engine model consists of two submodels to calculate the exact intake manifold pressure. The first model is adiabatic, which is used for describing the pressure dynamics. The additional parameter that indicates the heat exchange of the intake manifold is added to compensate steady state error of the model. The second model is the pressure ratio model between intake and exhaust manifolds, used to adjust the additional parameter to reduce the steady state error. The proposed model is validated using 216 steady state conditions with a root mean square error of 3.17 %. The transient performance of the model is also demonstrated by a comparison with the engine experimental results.