Fuel injection system

A shut off valve for use in a fuel injection system including an injector, the shut off valve control valve including a shut off valve member that is operable between open and closed operating positions to control the supply of fuel to the injector, the shut off valve member having a surface exposed to fuel pressure within a shut off control chamber, the shut off valve further comprising a control valve for controlling fuel pressure within the shut off valve control chamber, thereby to control movement of the shut off valve member between the open and closed operating positions.

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 three position valve operable between a first position in which fuel at the first injectable pressure level is supplied to the injector, 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 and a third position in which the pump arrangement communicates with a low pressure drain, thereby to permit spill-end of injection.