Simplified Operation of the Governor

Diesel Engine Fundamentals DOE-HDBK-1018/1-93 DIESEL ENGINE SPEED, FUEL CONTROLS, AND PROTECTION Simplified Operation of the Governor The governor controls the fuel rack position through a combined action of the hydraulic piston and a set of mechanical flyweights, which are driven by the engine blower shaft. Figure 28 provides an illustration of a functional diagram of a mechanical-hydraulic governor. The position of the flyweights is determined by the speed of the engine. As the engine speeds up or down, the weights move in or out. The movement of the flyweights, due to a change in engine speed, moves a small piston (pilot valve) in the governor's hydraulic system. This motion adjusts flow of hydraulic fluid to a large hydraulic piston (servo-motor piston). The large hydraulic piston is linked to the fuel rack and its motion resets the fuel rack for increased/decreased fuel. Figure 28 Simplified Mechanical-Hydraulic Governor Rev. 0 ME-01 Page 35