RPM regulator for fuel injection pumps

In an rpm regulator for use with a fuel injection pump associated with an internal combustion engine, said regulator including a housing within which a suction chamber is defined, an intermediate lever, a regulating spring means coupled to the intermediate lever, a guide shaft, a centrifugally operating governor sleeve positioned about the guide shaft and having its front end adjacent the intermediate lever for transmitting an rpm signal to the intermediate lever in opposition to a force exerted by the regulating spring means, and a working chamber defined by a space between an end of the guide shaft and the inside surface of the governor sleeve, the improvement comprising:

• a. a throttle aperture formed in the wall of the governor sleeve for providing fluid communication between the working chamber and the suction chamber;
• and
• b. at least one controllable relief bypass means connected to the governor sleeve for providing selective fluid communication between said working chamber and said suction chamber over a portion of the relative positional range of said governor sleeve with respect to said guide shaft whereby damping is effective over a predetermined load range.