The Position Control of a Gasoline Engine during Shutdown 2017-01-1630

Since the first stop-start system introduced in 1983, more and more vehicles have been equipped with this kind of automatic engine control system. Recently, it was found that there is strong correlation between engine resting position and the subsequent engine start time. The utilization of the synchronization time working from a required engine stop position prior the engine start request was shown to reduce start times. Hence the position control of an engine during shutdown becomes more significant. A naturally aspirated engine was modelled using the GT-Suite modelling environment to facilitate the development of position controllers using Simulink ®. The use of respectively the throttle and a belt mounted motor generator to provide a control input was considered. Proportional-Integral-Differential (PID), sliding mode and deadbeat control strategies were each used in this study. The control simulation results show that the PID control and sliding mode control can achieve accurate position control with deviations less than 0.1 degree from the target. However, the deadbeat control which was designed using an identified engine model gives poor tracking performance of a constant speed reference and unstable tracking of the constant deceleration reference. This study has produced two feasible control solutions to accurately position the crank shaft at the engines top dead centre location after shutdown. This allows the use of direct or assisted direct starting techniques which yield benefits in the quality of automatic stop/start systems.