US Patent 7216617 Engine starting assist system

An engine starting assist system includes an auxiliary ECU having a voltage booster, an engine ECU, a starter relay, and a starter that allows the engine to be started when a current flows through the starter relay. The auxiliary ECU and the engine ECU are powered by a battery and supply currents to the starter relay. When the engine ECU resets the supply of the current to the starter relay because of a voltage drop of the battery during starting of the engine, the auxiliary ECU increases the voltage supplied from the battery using the booster, thereby supplying the current to the starter relay.