| 摘要 |
PURPOSE:To control a fuel injection pressure to a given value, by constituting a device such that a plunger is reciprocated by alternately exerting a high pressure force and a low pressure force on a pressure chamber, and this causes boosting of fuel in a high pressure chamber, into which fuel from a fuel tank is fed, to supply the fuel to a fuel injection valve. CONSTITUTION:A plunger 4, having one end engaged with a high pressure chamber 2 so that it is slidable thereinto, is disposed in a casing 3 provided, inside, with a pressure chamber 1 having a wide cross section area and a high pressure chamber 2 having a narrow cross section area, and the other end thereof is mounted to a diaphragm 6 fastened in the casing 3. A chamber, positioned opposite to the pressure chamber 1 of the diaphragm 6, is open to the atmosphere through apertures 7. A shaft 8, turning in synchronism with a crank shaft, is fitted in a hole 9 in the casing 3, and through rotation of the shaft 8, a port 11 communicated with an air pump 13 and a port 12 communicated with the atmosphere are alternately connected to the pressure chamber 1. Reciprocation of the plunger 4 causes boosting of fuel fed from a fuel pump 15 to supply it to fuel injection valves 19-22. |
