A transient SI engine model for vehicle dynamic simulation

This study details an investigation into the modeling and simulation of SI engines, engine components, and vehicle powertrain systems. The work expands on previous studies in three areas: the description of powertrain system and its components, the formulation of spark-ignition (SI) engine component models and overall engine model, and lastly, the sensitivity analysis of the engine model and the simulation of powertrain systems.; A mathematical model of SI engines, with either carburetor, single-port fuel injection, or multi-port fuel injection systems, is derived. In the present engine model, the engine internal torque is a function of air/fuel ratio, engine speed, and throttle plate position. This engine model can account for the sudden change in throttle plate angle and estimate the engine transient behavior. The powertrain subsystems are also described to a certain extent, and the integration of the present engine model and a specific powertrain system is verified by further computer simulation.; The Taguchi Method is applied in sensitivity analysis (constant engine speed) which allows for an understanding of the engine parameters that are necessary to include in the model. In addition, the control variables which affect the engine dynamics and states can be examined. Using the simulation results, a simple fuel enrichment strategy is derived in order to compensate air-fuel mixture lean/rich tendency when the throttle plate is opened/closed rapidly. This confirms the controllability of the present engine model. Furthermore, a flywheel is attached to the engine crankshaft to emulate a powertrain system and account for the change in engine speed. Finally, the present engine model and a specific powertrain system are integrated and simulated to demonstrate their application in full-vehicle simulation.