Patent ID: 7584747

Claim:
A fuel system for an internal combustion engine comprising: a plurality of nozzle groups, each of the nozzle groups having a nozzle body with a fuel inlet and at least one nozzle outlet, a control passage, a nozzle supply passage and a drain, each of the nozzle groups further including a needle check movable between a first check position blocking the at least one nozzle outlet from the nozzle supply passage and a second check position where the at least one nozzle outlet is open to the nozzle supply passage, and each needle check further having a closing hydraulic surface exposed to a fluid pressure of the corresponding control passage; a common rail fluidly connecting with the fuel inlet of each of the nozzle groups and configured to supply a pressurized fuel to the nozzle supply passage of each of the nozzle groups at a first pressure; a plurality of pump groups each configured to supply a pressurized fuel to the nozzle supply passage of one of the nozzle groups at a second, higher pressure, each pump group including a mechanically actuated pressure intensifier having a tappet; each of the nozzle groups further including an electrically actuated needle control valve configured to control the needle check and being movable between a first needle control valve position blocking the control passage from the drain, and a second needle control valve position at which the control passage is open to the drain; and each of the pump groups further including an electrically actuated pump valve comprising a spill valve movable between a first pump valve position at which fuel is displaced from the pump group to a low pressure space and a second pump valve position at which fuel is displaced from the pump group to the nozzle supply passage of the corresponding nozzle group; and the fuel system further including a plurality of check valves each being positioned fluidly between one of the plurality of pump groups and the nozzle supply passage of one of the plurality of nozzle groups and blocking fluid flow from the common rail to the corresponding pump group.