A quantity regulating valve having a control slide valve for a fuel injection system

A quantity regulating valve for a direct injection fuel injection system for an internal combustion engine comprises a longitudinal slide 50 which is moveable in a housing 21 between a spring chamber 24 and a control chamber 23 and controls fuel flowing from a low pressure pump to a high pressure pump. Fuel is supplied to the control chamber 23 by way of a restrictor 66 or diaphragm valve. The slide 50 has two piston regions 53, 54 and an annular groove 60. In the closed position piston region 53 blocks inlet bore 31 and partially blocks outlet bore 33 allowing bore 33 to communicate with a fuel return bore 34. When pressure builds in control chamber 23 the slide 50 opens against the force of a spring 65, piston 53 allows inlet bore 31 to communicate with outlet bore 33 via groove 60 and the piston 53 prevents outlet bore 33 from communicating with the return bore 34. The outlet is controlled to open wider by a control edge formed on piston 53.