The present invention is an installation of an emergency starting switching device and/or direct current boosted boost circuit device. When the power of the starting battery is insufficient, the electric energy of the auxiliary battery is used to drive the starting motor in order to start the engine by operating the emergency starting switching device. And when the engine is started, the voltage of the ignition device or the fuel injection device is stepped up to strengthen its starting capability by means of a voltage boost by the direct current boosted boost circuit device.