Abstract: A control system for the fuel system of an engine which has electrically operated valves which control the quantity of fuel supplied to the combustion chambers of an engine includes a disablement controller which in a test situation can operate to prevent the supply of fuel to the combustion chambers in turn. The system also includes a comparator which observes the variation of an engine operating parameter e.g. fuel level during the test and trim circuit which acts to modify the amount of fuel supplied to the individual combustion chambers on the basis of signals provided by the comparator, so that each combustion chamber contributes substantially equally to the power output of the engine.

Abstract: A control valve for use in a fuel injection system of an engine comprises a valve member of plate like form and movable in an inlet chamber between a first seating and a second seating on opposite sides of the valve member. The first sealing is smaller in diameter than the second seating and surrounds a spill flow passage. The inlet chamber connects in use with the pump chamber of a fuel pump. When the valve member is in contact with the second seating a control chamber is formed which is connected by a restricted passage to the pump chamber. Flow of liquid from the control chamber is controlled by a valve element which is movable by an actuator and which conveniently controls flow through an opening in the valve member. In the closed position of the valve member it engages the first seating and the opening is closed by the element.