GOVERNOR: Flywheel which minimizes fluctuations of speed within the cycle but it cannot minimize fluctuations due to load variation. This means flywheel does not exercise any control over the mean speed of the engine. To minimize fluctuations in the mean speed which may occur due to load variation, the governor is used.

• The governor automatically controls the supply of working fluid to the engine with the varying load conditions and keeps the mean speed within certain limits.
• The function of a governor in automobiles is to limit fuel to the engine to a maximum safe speed when unloaded and to maintain a relatively constant speed despite changes in loading.