Injection timing control system for fuel-injection pump for engine

An injection timing control system for a fuel-injection pump for an engine, comprising:

• a phase angle regulator for varying the rotational phase angle of a drive shaft of the fuel-injection pump, said regulator including an input shaft adapted to be driven by the engine and an output shaft for driving the drive shaft of the fuel-injection pump, with a cylindrical extension of one of said input and output shafts coaxially surrounding an end portion of the remaining shaft in spaced apart relationship, a male spline formed on said end portion of said remaining shaft and a female spline formed on said cylindrical extension of said one shaft, at least one of said male and female splines having a helical spline configuration, a slider located in an annular space between said male spline and female spline and formed with splines meshing with said male spline and female spline, respectively, an annular cylinder formed between said cylindrical extension and said end portion, with a piston reciprocally received in said annular cylinder, and rigidly attached to said slider for joint movement therewith;
• said annular cylinder comprising a double chamber type cylinder including a first chamber portion in fluid communication with a first end surface of said piston and further including a second chamber portion in fluid communication with a second end surface of said piston;
• said phase angle regulator further including first port means in fluid communication with said first chamber portion and second port means in fluid communication with said second chamber portion and means for selectively supplying a stream of pressurized fluid to either said first chamber portion or said second chamber portion to selectively move said piston within said double chamber type cylinder, whereby said integrally attached slider is caused to move relative to said male and female splines to eliminate any deviation between an actual rotational phase angle of the fuel injection pump drive shaft and an optimum rotational phase angle for prevailing engine operating conditions.