Oil regulating pump for lubricating engines and method of controlling thereof

An oil regulating pump for supplying oil to an engine, comprising:

• a pump housing provided with a suction route and a discharge route;
• a drive shaft disposed in said housing and rotated by the engine;
• a primary plunger rotated by the drive shaft;
• a secondary plunger inserted into a hole provided in an end of the primary plunger and forming a pump chamber communicable with the suction route and the discharge route;
• a stepper motor having a rotor and output shaft and provided with a mechanism for converting rotation of the rotor into linear movement of the output shaft;
• a cam shaft abutting an end of said drive shaft and linearly disposed by the output shaft in order to reciprocate said drive shaft and to change the reciprocation stroke of said drive shaft;
• a stopper disposed adjacent to said stepper motor for stopping displacement of the output shaft in a standard position;
• and
• control means for positioning the output shaft to a desired command control position;
• said control means further including correction means for periodically returning the output shaft, in accordance with predetermined conditions, to the standard position prior to recommencing a command control position.