Liquid fuel pumping apparatus

A fuel injection pumping apparatus comprising a cylinder, a displacement piston located in said cylinder, a fuel outlet from one end of said cylinder, an inlet through which fuel can be admitted to said one end of the cylinder, a further cylinder, a fluid pressure operable member mounted within said further cylinder for moving said piston towards said one end of the first-mentioned cylinder thereby to cause fuel flow through said outlet, means operable upon movement of the piston to a predetermined position in said first-mentioned cylinder during delivery of fuel through said outlet to terminate flow of fuel through the outlet, valve means operable to place an end of said further cylinder in communication with a source of fluid under pressure to effect movement of the displacement piston in a direction to cause delivery of fuel through said outlet, further valve means operable to place said one end of the further cylinder in communication with the source of fluid under pressure to effect movement of the displacement piston in a direction to deliver fuel through said outlet, the apparatus also including a restricted orifice interposed between said further valve means and said one end of said further cylinder, whereby said further valve means may be operated before said first-mentioned valve means when it is required to supply fuel through the outlet, said orifice determining the rate of fuel supply through said outlet, said firstmentioned valve means being operated when the full rate of fuel supply through said outlet outlet is required.