Apparatus for regulating the timing of fuel injection in internal combustion engines

Claim 1

Apparatus for regulating the timing of fuel injection into the cylinders of an internal combustion engine wherein the injection is effected by a fuel injection pump which is adjustable to regulate the timing of fuel injection and receives fuel from the outlet of a fuel pump at a pressure which is a function of the rotational speed of the engine, comprising hydraulic timer means connected with the outlet of the fuel pump and having adjusting means connected with the fuel injection pump to regulate the timing of fuel injection as a function of changes in fuel pressure at the outlet of the fuel pump; adjustable regulating means for changing the fuel pressure at the outlet of the fuel pump; and control means for adjusting said regulating means as a function of changes in the load upon the engine, said control means comprising an electromagnet having an armature movable between a plurality of positions each indicative of a different load upon the engine and said regulating means comprising a pressure regulating valve having a valve member movable between a plurality of positions each corresponding to a different fuel pressure at the outlet of the fuel pump and each depending on a different position of said armature, said pressure regulating valve further comprising a cylinder for said valve member, resilient means arranged to bias said valve member in a given direction with a force which is a function of the position of said armature and conduit means connecting said outlet with said cylinder so that the fuel in said conduit means exerts on the valve member a force tending to move the valve member counter to said given direction, said cylinder having at least one relief port which is controlled by said valve member and communicates with said conduit means to an extend which is a function of the position of said valve member.