AN ENGINE-STARTING SIMULATION WITH FRICTION ESTIMATION: BACKGROUND AND MODEL VALIDATION

摘要

This paper describes an engine-starting simulation that uses models of the electrical, engine dynamics and engine thermodynamics subsystems combining them with engine friction models. One of these friction models uses the physical parameters of the engine as basis for estimating the friction torque. This allows engine performance prediction, hence the ability to size the electrical starting system, without engine availability. The resultant simulation is developed using SIMULINK/MATLAB~(TM) and it has been validated for two engines; the first is a 4-cylinder engine with a conventional valve train, and relatively high friction by today's standards, and the second is a more recent 3-cylinder engine with low-friction. Validation of the first engine was done based on matching its published starting tests with results obtained using this paper's simulation. The validation of the second engine was carried out by comparing engine test results with simulation results. Tests in the first case were for engine starting including firing and in the second case were for cranking only conditions.