Mechanical membrane fuel pump with stepped piston for the fuel supply of combustion engines, especially injection engines

摘要

The pump consists of an upper housing (12) with a fuel inlet pipe (14), an outlet pipe (18) leading to the injection system, and an excess fuel and gas return pipe (16), leading back to the fuel tank. The pump also has a return pipe (38) for surplus fuel from the injection system, situated at the top of the pump housing in line with the pump return pipe (16) and joining it slightly ahead of the pump return orifice (22). The section of the injection system return pipe (38) is made in the shape of a Venturi tube with a section which reduces towards the orifice and in the direction of the fuel flow. The pump also has a pressure regulating accumulator (30), with the two return pipes (16,38) situated above it, comprising a flat membrane with a rigid centre (32) stuck or moulded to its surface.