COVER AS-CENTER 3777885 - Caterpillar

Illustration 10 g01027696
Mechanical governor (1) Collar (2) Bolt (3) Lever assembly (4) Upper spring seat (5) Weights (6) Governor spring (7) Lower spring seat (8) Thrust bearing (9) Valve (10) Upper oil passage in piston (11) Piston (12) Lower oil passage in piston (13) Sleeve (14) Oil passage in cylinder (15) Drive assembly (16) Cylinder (17) Pin (18) LeverThe governor has governor flyweights (5) driven by the engine through the drive assembly (15). The governor has governor spring (6), valve (9) and piston (11). The valve and the piston are connected to one fuel rack through pin (17) and lever (18). The pressure oil for the governor arrives from the governor's oil pump that is on top of the injection pump housing. The oil that is used is from the engine lubrication system. Pressure oil flows through passage (14) and around sleeve (13). The throttle lever (governor control) controls the compression of governor spring (6). Compression of the spring always pushes down in order to provide more fuel to the engine. The centrifugal force of governor flyweights (5) always pulls in order to reduce the amount of fuel to the engine. When these two forces are in balance, the engine runs at the desired rpm (governed rpm).The governor valve (9) is shown in the position when the force of the governor spring is in balance.When the engine load increases, the engine rpm decreases and the rotation of governor flyweights (5) will slow. The governor flyweights will move inward. Governor spring (6) moves valve (9) downward. This allows the oil flow from the lower passage (12) around the valve (9) and through the upper passage (10) to fill the chamber behind piston (11). This pressure oil pushes the piston (11) and the pin (17) downward in order to deliver more fuel to the engine. The upper portion of the valve inhibits the oil flow around the valve. Engine rpm goes up until the rotation of the governor flyweights is fast enough to be in balance with the force of the governor spring.When there is a reduction in engine load, there will be an increase in engine rpm and a corresponding increase in the rotation of governor flyweights (5). This will move valve (9) upward. This stops oil flow from the lower passage (12). Further, the oil that is above piston (11) flows around valve (9). Now, the pressure between the sleeve (13) and piston (11) pushes the piston and pin (17) upward. This causes a reduction in the amount of fuel to the engine. Engine rpm will decrease until the centrifugal force (rotation) of the governor flyweights is in balance with the force of the governor spring. When these two forces are in balance, the engine will run at the desired rpm (governed rpm).When engine rpm is at low idle, a spring-loaded plunger in lever assembly (3) comes in contact with a shoulder on the adjustment screw for low idle. To stop the engine, push