Supercapacitor-based torque booster for downsized ICE vehicle

An effective approach for improving the fuel economy and reducing the emission of CO/sub 2/ and other harmful pollutants from ICE vehicles is to employ a down-sized supercharged engine. However, supercharged ICEs exhibit a relatively low torque capability at low engine speeds. In order to overcome this problem, an electrical torque boost may be applied for short periods, whilst accelerating and changing gear. The paper describes the operational requirements of a torque boost system which employs a super-capacitor energy storage buffer, and considers the design and sizing of the electrical machine.