Abstract: A fuel system for supplying pressurised fuel to a plurality of fuel injectors (14a-14f) comprises an accumulator assembly (16) having first and second accumulator volumes (18, 20) defined within a common accumulator housing (22), supply means (42) for supplying fuel at a supply pressure level to the first accumulator volume (18) and a plurality of unit pumps (10a-10f). Each unit pump is arranged to receive fuel at the supply pressure level from the first accumulator volume (18) and pressurises said fuel to an injectable pressure level for supply to the second accumulator volume (20). Each unit pump (10a-10f) includes a pumping plunger (50) for pressuring fuel within an associated pump chamber (52) and being integrated with the accumulator housing (22) so as to permit communication between the first accumulator volume (18) and the pump chamber (52) internally within the accumulator housing (22).

Abstract: A fuel injection system for supplying pressurized fuel to a fuel injector, the fuel injection system comprising an accumulator volume for supplying fuel at a first injectable pressure level to the fuel injector through a fuel supply passage, a pump arrangement for increasing the pressure of fuel supplied to the injector to a second injectable pressure level, and a valve arrangement operable between a first position in which fuel at the first injectable pressure level is supplied to the injector and a second position in which communication between the injector and the accumulator volume is broken so as to permit fuel at the second injectable pressure to be supplied to the injector. The injection system may include a valve arrangement in the form of a three-position valve or may include a shut off valve for controlling the supply of fuel through the fuel supply passage.

Abstract: A fuel system for use in an internal combustion engine comprising a fuel pump having a pumping cycle during which fuel is pressurised to a high level within a pumping chamber for delivery to an injector. The injector is arranged to provide a primary fuel injection event, and a secondary fuel injection event within the same pumping cycle. The injector includes a valve needle which is engageable with a valve needle seating to control fuel delivery and an injection control valve arrangement for controlling movement of the valve needle so as to control the primary and secondary fuel injection events. The fuel system further comprises an accumulator volume for storing high pressure fuel for delivering the secondary fuel injection quantity, and additional valve arrangement for controlling the supply of fuel stored within the accumulator volume to the injector for the secondary injection event.

Abstract: A fuel injection system for supplying pressurised fuel to a fuel injector, the fuel injection system comprising an accumulator volume for supplying fuel at a first injectable pressure level to the fuel injector through a fuel supply passage, a pump arrangement for increasing the pressure of fuel supplied to the injector to a second injectable pressure level, and a valve arrangement operable between a first position in which fuel at the first injectable pressure level is supplied to the injector and a second position in which communication between the injector and the accumulator volume is broken so as to permit fuel at the second injectable pressure to be supplied to the injector. The injection system may include a valve arrangement in the form of a three-position valve or may include a shut off valve for controlling the supply of fuel through the fuel supply passage.

Abstract: A fuel system for use in an internal combustion engine comprising a fuel pump having a pumping cycle during which fuel is pressurised to a high level within a pumping chamber for delivery to an injector. The injector is arranged to provide a primary fuel injection event, and a secondary fuel injection event within the same pumping cycle, in use. The injector includes a valve needle which is engageable with a valve needle seating to control fuel delivery and an injection control valve arrangement for controlling movement of the valve needle so as to control the primary and secondary fuel injection events. The fuel system further comprises an accumulator volume for storing high pressure fuel for delivering the secondary fuel injection quantity, and additional valve arrangement for controlling the supply of fuel stored within the accumulator volume to the injector for the secondary injection event.

Abstract: A pump/injector includes a high pressure pump which delivers fuel to an inwardly opening fuel injection nozzle. Also provided is a spill valve which is connected to the pumping chamber of the pump and through which the pumping chamber is filled with fuel from a source by way of a first non-return valve. Connected intermediate the spill valve and the non-return valve is a branch passage to the spring chamber of the nozzle and the pressure in the spring chamber when the spill valve is opened to terminate delivery of fuel is controlled by a valve.