Abstract: The invention relates to a fuel injection pumping apparatus which includes a feed pump the output pressure of which is controlled by valve. The feed pump supplies fuel to an injection pump under the control of a shuttle which is movable in a bore. The extent of movement of the shuttle determines the amount of fuel supplied by the injection pump to the associated engine. In addition, a fluid pressure operable device is provided to control the timing of injection of fuel to the engine, and the pressure for controlling the device is obtained from a point intermediate a fixed restrictor and a variable restrictor constituted by a groove formed in the shuttle and a port formed in wall of the bore accommodating the shuttle. Fuel from the outlet of the pump flows through the fixed and variable restrictors.

Abstract: A fuel pumping apparatus for supplying fuel to an internal combustion engine includes an injection pump which delivers fuel through a delivery passage which includes a spring loaded delivery valve. A vent conduit extends from the delivery passage, and communicates with a vent conduit during a delivery stroke of the injection pump. The vent conduit communicates with the delivery passage intermediate the injection pump and the delivery valve, and the vent passage includes a screwed plug at its end and a valve element which is resiliently loaded into contact with a seating. The seating is positioned adjacent the vent conduit so that the amount of fuel in the conduit during normal operation of the apparatus, is as small as possible.

Abstract: An electrical inverter comprises positive and negative supply lines, first and second thyristors the anodes of which are connected to the positive line and the cathodes of which are connected respectively to the anodes of third and fourth thyristors. An oscillatory commutating circuit including a capacitor and an inductor is provided and which is connected between the anodes of the third and fourth thyristors and also a firing circuit is provided to provide gate signals to the first, fourth, third and second thyristors in that order. In addition, means is provided to over-damp the oscillatory circuit thereby to limit the commutating voltage.

Abstract: A fuel injection pumping apparatus includes an injection pump to which fuel is supplied by means of an axially movable shuttle which is contained within a cylinder. Fuel is supplied to one end of the cylinder through a metering valve from a first source of fuel under pressure. The fuel contained in said one end of the cylinder is displaced to the injection pump by applying fuel under pressure to the other end of the cylinder containing the shuttle from a further source of fuel under pressure. The pressure of the further source of fuel is higher than that of the first mentioned source.