Page 49 - Introduction to Marine Engineering

56 Diesel engines

-Speed
adjustment

Flyweight

Power
Oil
supply piston
Oil
drain-

Figure 2.22 Mechanical governor

weights outwards; this lifts the vertical spindle and compresses the
spring until an equilibrium situation is reached. The equilibrium
position or set speed may be changed by the speed selector which alters
the spring compression.
As the engine speed increases the weights move outwards and raise
the spindle; a speed decrease will lower the spindle.
The hydraulic unit is connected to this vertical spindle and acts as a
power source to move the engine fuel controls. A piston valve connected
to the vertical spindle supplies or drains oil from the power piston which
moves the fuel controls depending upon the flyweight movement. If the