Fuel injection systems

Claim 1

A fuel injection system for supplying fuel to an internal combustion engine comprising a displacment piston movable within a first cylinder for generating a first fluid pressure, an outlet from one end of the cylinder, a valve engageable by said piston during the movement of the piston towards said one end of the cylinder, said valve when operated by said piston acting to lower the first pressure in said one end of the cylinder, a second cylinder for generating a second fluid pressure, a stepped valve member slidable in said second cylinder, the narrower end of said valve member being shaped to co-operate with a seating defined at one end of said second cylinder to control the flow of fuel through an orifice from said one end of the second cylinder, the wider end of said valve member being subject to said second fluid pressure to urge the valve member into contact with the seating, the area defined between the narrower and wider portions of the valve member being subject to said first pressure at said outlet whereby when said first pressure is sufficiently high the valve member will be lifted from its seating to permit flow of fuel, and a push pin interposed between said valve and said valve member, whereby during continued movement of the displacement piston after engaging said valve, the push pin will transmit motion between said displacement piston and said valve member whereby the valve member will be positively moved in the direction to prevent flow of fuel through said orifice.