直噴ガソリンエンジン用高圧燃料ポンプの開発

抄録

Direct injection (DI) is becoming increasingly popular among gasoline automotive engines, due to its benefits for fuel consumption and engine output. A key component of a DI system is the fuel pump, which must deliver fuel at much higher pressures than a conventional spark ignition (SI) engine. For a DI fuel pump, maximum fuel flow rate, maximum operation speed, electrical power consumptions and noise are conflicting requirements. This paper describes the development of a compact single-cylinder DI fuel pump which achieves increased fuel flow rates while consuming decreased electrical power and generating less noise, compared to conventional DI fuel pumps currently in the market. This is achieved by the introduction of a new concept for the flow rate control valve, so called normally close valve. The construction of this valve allows it to have smallest air gap between magnetic surfaces at valve open position, which makes it possible to generate high magnetic force with less electrical energy. Moreover, the magnetic force is used for handling hydraulic force, which makes it possible to handle higher flow rate. In addition, the flow rate control valve moves passively by the hydraulic forces, such that the impact noise at valve opening is reduced significantly.