Device for automatic speed control of a diesel engine

A device for control of fuel flow for automatic speed control of an associated diesel engine having an associated fuel control device for controlling the fuel to the diesel engine which comprises:

• a working cylinder and a working piston, said working piston being movable responsive to fluid pressure on each side thereof;
• means coupling said working piston to the associated fuel control device to vary the quantity of fuel delivered to the associated diesel engine as a function of the working piston position;
• a first fluid conduit in fluid communication with said working cylinder and one side of said working piston;
• a second fluid conduit in fluid communication with said working cylinder and the other side of said working piston;
• a first valve element disposed in series with said second fluid conduit;
• means for balancing two fluid pressures between first and second parts thereof without mixing the two fluids under pressure, one part of said means for balancing being in fluid communication with said second fluidconduit;
• fluid conduit;
• a first valve in fluid communication with said second part of said means for balancing which selectively connects said second part of said means for balancing to ambient or an associated source of fluid pressure;
• a second valve in fluid communication with said first fluid conduit which selectively connects said first fluid conduit to ambient or the associated source of fluid pressure;
• means for producing a first signal which is a function of the speed of the associated diesel engine;
• means for producing a second signal which is a function of a predetermined engine speed;
• means for comparing said first signal and said second signal;
• and
• means for controlling said first valve element, said first valve and said second valve responsive to said means for comparing.