The electric fuel pump conveyed by an oil pump installed in the tank is transported through the filter in the pipeline to the oil channel assembly. The oil pump is designed to provide the fuel pressure that is higher than the regulating pressure required by the nozzle. The excess fuel will go back to the oil pipe and return to the tank. The detection terminal of the oil pump is located in the engine room. When the engine stops running, the battery voltage can be applied on the detection terminal to make the oil pump start and operate.