Improved dynamic performance of turbocharged SI engine power trains using clutch actuation

This article proposes a new model-based optimal control strategy that is able to substantially reduce the torque lag present in spark-ignited turbocharged engine systems. The key idea is to utilize an automated wet clutch as an additional control actuator.The optimal control signals are obtained using a mean value model of the combined engine-power-train system and numerical optimization methods. The optimization problem is defined by choosing a representative test case and an objective function that parametrizes the trade-off between fast torque dynamics and comfort.The proposed control strategy achieves a reduction of the time lag to reach 90% of full load torque by up to 70%. These results are experimentally confirmed on an engine dynamometer for a downsized and turbocharged SI engine.