Patent ID: 7802557
Filing Date: 2010-09-28
Classification: F02M,F04B

Abstract:
1. An electronic-injection fuel-supply system for an internal-combustion engine that comprises at least one injector having a desired fuel-supply pressure, a fuel pump, and a connection pipe connecting the fuel pump hydraulically to the at least one injector; the fuel pump comprising: a variable-volume pumping chamber; a one-way intake valve; a one-way delivery valve; a mobile piston is coupled to the variable-volume pumping chamber to vary cyclically the volume of the variable-volume pumping chamber and the piston integrates within it the one-way intake valve; and an electromagnetic actuator device, which impresses a reciprocating motion on the piston, comprises an electromagnetic actuator for actuating the piston during an intake phase, and comprises a spring for actuating the piston during a delivery phase, wherein the electromagnetic actuator comprises: a coil; a fixed magnetic pole, which is set within a housing body and has a central hole to enable flow of fuel along a central supply channel of the housing body; and a mobile anchor, which is set within the housing body and has a central hole to enable flow of the fuel along the supply channel, is rigidly connected to the piston and is designed to be magnetically attracted by the fixed magnetic pole when the coil is excited, wherein the spring is sized so that the force of pre-loading exerted by the spring on the piston is equal to the useful area of the piston multiplied by the desired fuel-supply pressure so that the spring is able to push the fuel out of the variable-volume pumping chamber through the one-way delivery valve and towards the connection pipe giving out into the at least one injector only if a pressure of fuel within the connection pipe is lower than the desired fuel-supply pressure, and wherein the spring is set within the central hole of the mobile anchor and is compressed between the fixed magnetic pole and the piston.