US Patent 7849840 Electric motor assisted mechanical supercharging system

This apparatus and method introduces to the internal combustion engine, with a centrifugal compressor or positive displacement air supercharger, a high speed electric motor/generator which is drivingly coupled to a drive shaft system for the purpose of acceleration and generation of pressurized air at low engine speeds and incorporation of one-way and/or magnetic clutches to provide maximum power to the engine operation at all times. The motor/generator when not driving the supercharger is putting energy back into the engine battery.