High-pressure common rail EFI technology refers to an oil supply method that completely separates the generation of injection pressure from the injection process in a closed-loop system composed of high-pressure oil pump, pressure sensor and electronic control unit (ECU). It uses the high-pressure oil pump to deliver high-pressure fuel to the common rail, and realizes accurate control through the oil pressure in the common rail, so that the pressure of the high-pressure oil pipe has nothing to do with the engine speed, which can greatly reduce the degree that the fuel supply pressure of the diesel engine changes with the engine speed.