| 摘要 |
A fuel injection system (10) for injecting fuel into the combustion chamber of an internal combustion engine includes a multi-way valve (30), a solenoid (42) for controlling the operation of the valve, a shuttle valve (38) that is moved within a shuttle chamber (37) in response to the change of state of the solenoid, and an intensifier piston (62) having an upper cylinder (62) movable within actuating chamber (49) and a lower cylinder (66) movable within metering chamber 50. The position of the shuttle valve, in turn, regulates the admission of pressurized fuel from a high pressure pump (152) into the actuating chamber (49) to drive the intensifier piston in a first direction. The lower cylinder 66 of the piston 62 is movable within the metering chamber (50) to amplify the pressure of the fuel to a level several times greater than supply pressure prior to introducing same into a fuel injector (78) for discharge into the combustion chamber. A T-shaped passage (70) in the piston (66) allows the injection phase of the cycle of operation to be terminated sharply by a rapid dissipation of the pressure buildup. Variable restrictions (144, 146) such as a needle valve, are disposed in a return conduit that allows the fuel in the actuating chamber (49) to be returned to the fuel reservoir (39) and to regulate the volume of fuel that can return to the reservoir per unit of time during the metering phase of operation.
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