Reduction of engine torque ripple at starting with belt driven integrated starter generator

This paper describes a control method of belt driven integrated starter generator (ISG) to reduce the engine torque ripple at starting, especially before combustion. It presents an analytical model of an engine and a belt without considering combustion, and proposes a control algorithm that manipulates the torque of ISG to reduce a vibration of the engine based on the estimated engine torque ripple and the belt dynamics between the engine and ISG. This method does not require any other information except crankshaft angle and ISG speed which are already available in the vehicle. Using proto type ISG and engine system, some simulations and experiments are carried out to verify the algorithm. The experimental results reveal more than 50% reduction of the ripple torque.