Advance and retard system for fuel injector pump - has sprung pistons slidable in coaxial different dia. cylinders linked by bore with push rod

摘要

The advance retard mechanism consists of a first piston (1) able to slide inside a cylinder (3) against a return spring (4) when its pressure chamber (5) is subjected to engine speed dependant fuel pressure (6). The piston movement is transferred to the fuel pump advance retard lever (7). A fuel return flow (15) is provided at the spring end of the cylinder. A second piston (8) slides inside a second cylinder arranged in tandem to the first cylinder. The two pistons are joined by a push rod (11) passing through a boring (11a) in the cylinder dividing wall. A restricted bore (13) allows fuel pressure from the first pressure chamber (5) to act on the second piston. The corresponding fuel pressure return pipe (16) has a temp. dependant restrictor valve (17).