Abstract: A fuel injector for a compression ignition engine comprises a fuel injection nozzle, a valve controlled fuel supply chamber located behind the injection nozzle for storing a quantity of fuel, a port for admitting fuel to the supply chamber, a fuel piston operating in the supply chamber for compressing the fuel stored therein and expelling the fuel therefrom via the injection nozzle, and a hydraulic actuator means responsive to engine cylinder pressure for actuating the fuel piston. The hydraulic actuator means includes a spring loaded shuttle valve arranged to reciprocate between two limit positions in accordance with cyclical variations of gas pressure in the engine cylinder, and pumping means for controlling the supply of pressurized hydraulic fluid to actuate the fuel piston in accordance with the position of the shuttle valve.

Abstract: A pressurized hydraulic sump system comprises a sump manifold to which a variable volume reservoir is connected, and is characterized by a piston which is displaceable by hydraulic means to vary the volume of the reservoir in accordance with the position of a valve which is responsive to sump pressure so that the piston is displaced in one or other direction according to whether the sump pressure is greater or less than a predetermined value.

Abstract: In a system comprising first and second drive units each including one or more hydraulic motors, a two-position valve is provided in circuit with the motors of one drive unit, the motors of the other drive unit being supplied independently of the valve; the valve has a first operative position for blocking flow of working fluid to the one drive unit and a second operative position for permitting flow of working fluid to the one drive unit, the valve being operable between its first and second positions for selective operation of one or both drive units.