Fuel injector

A fuel injector for an internal combustion engine of a compression ignition type, comprising in combination:

• 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, a supply of pressurized hydraulic fluid, and hydraulic actuator means responsive to engine cylinder pressure for actuating the fuel piston, the actuator means including 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, the spring-loaded shuttle valve being slidable in a valve cylinder having an inlet for pressurized hydraulic fluid and an outlet communicating with the fuel piston, said pumping means comprising a reciprocatory free piston operating in a cylinder providing a pump chamber communicating with said valve cylinder, said pump chamber being connected to said inlet in one limit position of the shuttle valve and being connected to said outlet in the other limit position of the shuttle valve.