FUEL SYSTEM
SYSTEMS OPERATION
the bushing and plunger. The pilot valve plunger has a land that controls the oil flow through the ports in the bushing. When the pilot valve plunger is moved down, high pressure oil goes to the bottom of the power piston and the power piston will move up. When the pilot valve plunger is moved up, the oil on the bottom of the power piston is released to the sump and the power piston moves down. When the pilot valve plunger is in the center (balance) position, the oil port to the bottom of the power piston is closed and the power piston will not move. The pilot valve plunger is moved by the ballhead assembly.
When the engine is in operation at a steady speed the land on the pilot control valve is in the center of the control port of the bushing. A decrease in load will cause an increase in engine speed. With an in- crease in engine speed the flyweights move out and raise the speeder rod and floating lever. This raises the pilot valve plunger and releases oil from the bottom of the power piston. As the power piston moves down, the output terminal shaft moves in the decrease fuel direction. When the output terminal shaft moves, the actuating compensation piston moves up and causes a suction on the oil under the receiving piston which moves down. The floating lever is pulled down by the receiving piston and the lever moves the pilot control valve down to close the control port. The output terminal shaft and power piston movement is stopped. As the engine speed returns to normal, the flyweights move in and the speeder rod moves down. When the oil pressure in the compensation system and the sump oil become the same through the needle valve, the receiving compensation piston moves up at the same rate as the speeder rod moves down. This action keeps the pilot valve plunger in position to close the port.
The ballhead assembly has a ballhead, flyweights, speeder spring, thrust bearing, speeder plug and speeder rod. The ballhead assembly is driven by a gear and shaft from the driven gear of the oil pump. The speeder rod is fastened to the thrust bearing which is in contact with the flyweights. The speeder rod is connected to the pilot valve plunger by a lever. The speeder spring is held in position on the thrust bearing by the speeder plug. As the ballhead turns, the flyweights move out due to centrifugal force. This will make the flyweight toes move up and cause compression of the speeder spring. When the force of the speeder spring and the force of the flyweights are equal the engine speed is constant. The speeder plug can be moved up or down manually to change the compression of the speeder spring which will change the speed of the engine.
An increase in load will cause a decrease in engine speed. When engine speed decreases, the flyweights move in and lower the speeder rod and floating lever. This lowers the pilot valve plunger and lets pressure oil go under the power piston. The power piston moves up and turns the output terminal shaft in the increase fuel direction. When the output terminal shaft moves, the actuating compensation piston moves down and causes a pressure on the receiving piston which moves up. The floating lever is pushed up by the receiving piston and the lever moves the pilot valve plunger up to close the control port. The output terminal shaft and power piston movement is stopped.
The compensation system gives stability to engine speed changes. The compensation system has a needle valve and two pistons-an actuating piston and a receiving piston. The actuating piston is also con-nected to the output terminal shaft by the compensa- tion adjusting lever and linkage system. A fulcrum that is adjustable is on the lever. When the position of the fulcrum is changed, the amount of movement possible of the actuating piston is changed.
A change to the speed setting of the governor will give the same governor movements as an increase or decrease in load.
The receiving piston is connected to the pilot valve plunger and the speeder rod by a lever.
A lever on the speed adjustment shaft is used to change the engine speed. The speed adjustment shaft moves the speeder plug up and down to change the force of the speeder spring.
The needle valve makes a restriction to oil flow between the oil sump and the two pistons.
This governor is also equipped with speed droop, however, it must be adjusted inside the governor.
When the actuating piston moves down, the piston puts a force on the oil under the receiving piston and moves it up. When the receiving piston moves up it raises the pilot valve plunger to stop the flow of oil to the bottom of the power piston.
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