Pump system with high pressure restriction

A method of controlling a pump system for a fuel injection system, the pump system having a body defining a high pressure pumping chamber, a plunger disposed in the pumping chamber for pressurizing fuel, a high pressure outlet, a high pressure fluid line connecting the pumping chamber to the outlet, and a control valve along the fluid line, the control valve including a first valve body movable between a closed position in which pressurized fuel is routed from the pumping chamber to the outlet and an open position in which pressure relief is provided to the fluid line, the method comprising:

• controlling a valve and restriction arrangement along the fluid line, including a restriction and a second valve body, the second valve body being movable between an open position in which fuel flow from the pumping chamber is generally unrestricted by the restriction and a closed position in which fuel flow from the pumping chamber is significantly restricted by the restriction to store energy in the pumping chamber, the valve and restriction arrangement being controlled so as to control fuel flow from the pumping chamber to the outlet.