A multiple locally-linearized diesel engine model

The simulation of a diesel engine power source for off-road vehicle powertrains can be simplified by controlling an electric motor to mimic the operation and response of the engine to changes in loading and governor setting. The objective of this research was to develop a diesel engine model to be used to control an electric motor so that it produced torque-speed characteristics closely matching those of a diesel engine. A multiple locally-linearized submodel approach was applied to a turbocharged diesel engine with nine submodels being used to represent the engine dynamics over discrete segments of the engine operating range. A bumpless transfer method was used for modeling the process and ensuring a smooth transition between submodels when the engine operating point was switching from one operating zone to another. The model was verified by comparing the simulation and experimental results over the complete range of engine speed and load. The results showed that the model could represent engine dynamics successfully in both a transient phase and steady state. The advantages of linear models for controller design and real-time implementation were retained through this model.