Energy conversion analysis for mild hybrid electric vehicles equipped with an electric supercharged SI engine via multi-domain acausal modeling

•Multidomain model of mild hybrid electric vehicle with electric supercharged engines.•Equivalent circuit model for an integrated starter generator with a belt drive.•Regenerative electric power utilization for an electric supercharging (eSC) system.•Energy conversion analysis for fuel, mechanical, electrical, and thermal fluid.•Fuel consumption and dynamic performance improvement quantification by the eSC.