Speed governing device (governor) of engine

The speed governing device (governor) is a device for recovering the original engine speed when the engine speed changes due to fluctuation of the load applied to the engine in the constant rotation and constant output state. By this device, the engine maintains the set speed regardless of some load fluctuation.

In general, an air-cooled gasoline engine or a diesel engine uses a centrifugal mechanical governor using the balance between centrifugal force of a governor weight rotating in synchrony with engine rotation and tensile force of a governor spring, and the structure is shown in the drawing. The governor is often equipped on the cam shaft in the air-cooled gasoline engine, on the crank shaft in the horizontal diesel engine, and on the fuel cam shaft in the vertical diesel engine.

Centrifugal force of the governor weight has a function of decreasing the engine speed, and tensile force of the governor spring has a function of increasing the engine speed, and when they are balanced, engine rotation is stabilized.

For adjusting rotation, movement of the governor lever changes the amount of fuel injection by opening and closing the throttle valve of the carburetor in the air-cooled gasoline engine and by moving the control rack of the injection pump in the diesel engine.

For example, when the engine speed decreases due to increase of the engine load, centrifugal force of the governor weight decreases so that tensile force of the governor spring overpowers, which increases the amount of fuel and recovers the original engine speed. When the engine load decreases, the opposite operation is performed.

In general, many of vertical diesel engines and the like use two governor levers or multiple governor springs to achieve more stable and precise control.