Intensified high-pressure common-rail supply pump

Abstract

A fuel pump, a fuel-pressure intensifier sub-assembly and a method of producing intensified high-pressure fuel are disclosed. The pump has a metered fuel circuit, a plurality of low-pressure bores with low-pressure plungers disposed therein, an intensifier bore with a piston disposed therein, a resilient bias member acting on the piston, a high-pressure bore with a high-pressure plunger at least partially disposed therein and a fuel outlet port. The pump operates in alternating fuel-in-take and fuel-pumping phases of operation under the influence of a rotary drive shaft with a cam and cooperating cam followers. By selecting the pumping surface areas of the low-pressure plungers and the high-pressure plunger, it is possible to select the fuel-pressure generated by the fuel pump. This pressure differs from the pressure generated by the low-pressure pumping plungers alone by an amount which is equal to the ratio of the aggregate surface area of the low-pressure pumping plungers to the surface area of the high-pressure pumping plunger.