Volume reducer for pressurizing the common rail in i.c. engine fuel injection systems to improve starting

摘要

A hydraulically activated fuel injection system (10) uses a common rail (12) that is maintained at relatively high pressure by a pump (11) when the engine (9) is running. During start-up, a volume reducer (39) is used to pressurize the common rail (12) until the pump (11) can take over. A member (41) of the volume reducer (39) protrudes through one end of the common rail (12) and is movable into and out of the common rail (12). When the ignition is activated, the member (41) advances into the common rail (12) causing the fluid volume to decrease and the pressure within the hydraulic system (10) to increase, thereby allowing activation of the fuel injectors (13) and starting the engine (9) before the system pump (11) is able to supply high pressure fluid to the common rail (12). Once the pump (11) is able to sustain system pressure to the desired level, the member (41) can retract to its original position.