Patent ID: 7509947
Filing Date: 2009-03-31
Classification: F02M

Abstract:
1. A fuel pump for use in an internal combustion engine, the fuel pump comprising: a pump housing provided with a plunger bore and a pump outlet that is configured for connection to a fuel injector via a fuel supply line, a pumping plunger that is movable within the plunger bore by means of a cam drive arrangement to perform a pumping stroke to pressurise fuel within a pumping chamber, an outlet valve arranged and configured to control the flow of fuel from the pumping chamber to the pump outlet, a cam follower arrangement interposed between the cam drive arrangement and the pumping plunger so as to transmit a drive force of the cam drive arrangement to the pumping plunger, wherein the cam follower arrangement includes a timing advance piston for advancing or retarding the timing of the pumping stroke, and a controller for controlling the timing advance piston so as to advance or retard the timing of the pumping stroke, wherein the timing advance piston is provided with a groove on its outer surface for receiving fluid, thereby to provide a centralising force to the timing advance piston in use.