Compression ignition engine fuel pump - has superimposed staged double piston arrangement with spring loaded second piston

摘要

The IC engine fuel injection pump has a superimposed arrangement of two pistons. The piston controls the working space. The second piston is spring loaded and has a longitudinal orifice which interconnects the pump working space with the pump pressure chamber. The second piston has a pressure contact area which after closure of a control orifice in the first piston isolates the piston spaces and thus generates a steep sudden rise in the working pressure of the pump. Both pistons have a staged configuration, and the annular contact area, contacts a counter stop at a free clearance distance between the two pistons.