Compression operated injector with fuel injection control

In a compression operated diesel fuel injector, for an internal combustion engine, of the type having a housing means with a compression operated piston means therein, the piston means having a cylinder means thereon;

• a pump plunger fixed in the housing means and operatively associated with the cylinder means, the cylinder means and pump plunger defining an injection pump chamber and said piston means defining with the housing means a fuel control chamber;
• the housing means having a supply passage to the fuel control chamber for supplying fuel thereto and, a fuel return passage from the control chamber for the return of fuel to a source of low pressure fuel;
• and, a solenoid valve means operatively positioned to normally block flow of fuel from the fuel control chamber to the fuel return passage, the improvement wherein a variable flow orifice means is operatively associated with said fuel return passage next adjacent to said solenoid valve means whereby to control the pressure of fuel in said fuel return passage upstream of said variable flow orifice means as a function of engine speed and load when the solenoid valve means is energized, said variable flow orifice means thus being operative so as to regulate the flow of fuel from the control chamber whereby to control engine compression operation of the cylinder means for corresponding regulation of the rate of fuel injection from the fuel injector as a function of engine speed and load.