3883614 Volvo.Penta Pipe

3161 Governor
Refer to Caterpillar 3161 Governor Service Manual, Form No. SENR3028 for additional information.
3161 Generator Set Governor
(1) Manual speed setting control. (2) Speed adjusting motor head. (3) External droop adjustment.The 3161 Governor is a mechanical-hydraulic governor that senses (feels) engine speed and is connected to the carburetor by mechanical linkage. The governor controls the rate of fuel and air that is mixed in the carburetor. The fuel air mixture enters the inlet manifold and then goes into the cylinders for combustion as needed for engine loads.The speed adjusting motor is located on the governor cover and runs on 24 volt DC power. When the motor is actuated, it rotates a speed adjusting screw to adjust the position of the governor speed adjusting lever.Engine speed can be increased or decreased by the slotted speed setting adjustment located on the front of the governor. Turn the speed setting adjustment clockwise to increase the speed setting, and counterclockwise to decrease the speed setting. The high and low speed stops will limit the adjustments.Droop and compensation can be adjusted on the governor as needed for stability of engines with different rates of engine speed changes.The 3161 Governor has a maximum of 8 N m (6 lb ft) of torque output over the full 42 degrees of terminal (output) shaft rotation in both the fuel ON and OFF directions. Because the governor terminal shafts are moved in both directions by hydraulic pressure, no return spring is used on the outside of the governor. A 1.4 N m (1 lb ft) spring inside the governor moves the terminal shafts to the full shutoff position when the governor is not in operation.The recommended travel (rotation) of the terminal shafts is approximately 30 degrees from low idle to full load. This gives extra travel at each end for the governor to make a complete shutdown and gives maximum fuel when needed.The 3161 Governor is connected to the engine lubrication oil system. The oil supply (under pressure) is sent to the governor through an orifice and internal passages. The governor keeps the correct oil level and drains excess oil back into the engine, this gives a constant flow of oil through the governor.After removal or overhaul, the governor must be filled with approximately 1.8 liters (2 U.S. qts) of clean engine oil before engine startup. The oil fill plug on the 3161 Governor is located on the top cover.
Schematic of the 3161 Governor (Increased Fuel Position)Operation Of The 3161 Governor
Refer to Caterpillar 3161 Governor Service Manual, Form No. SENR3028 for additional information.Make reference to the 3161 Governor Schematic for use with the system operation that follows. The schematic shows the governor pilot valve in the increased fuel position.The 3161 Governor uses engine lubrication oil for its hydraulic system. The oil supply (under pressure) is sent to the governor oil reservoir through an orifice which can be removed from the governor housing for cleaning. The oil goes through internal passages to the suction side and then to the pressure side of the gerotor pump as the drive shaft is turned by the engine. An accumulator spring and piston keeps the pump pressure at approximately 690 kPa (100 psi). The accumulator piston moves up in its cylinder until the pump pressure is 690 kPa (100 psi). At this time, ports in the piston are opened to control the pump pressure.The pump pressure, as set by the accumulator, controls the work output of the governor.Increase In Speed Setting
When the speed setting shaft is turned clockwise, the speed setting of the governor is increased. The high idle screw limits the high speed setting of the governor. As the speed setting shaft turns, the speed setting lever pushes down on the floating lever which is fastened to the speeder plug. The downward pressure on the speeder plug puts the speeder spring under compression. The speeder spring force then becomes greater than the centrifugal force of the ballhead flyweights, and the ballhead pilot valve plunger is moved down. This increases the governor speed setting.As the pilot valve plunger is moved down, pressure oil moves under the power piston and pushes the piston up. This moves the terminal lever up and the output shafts are turned in the "increase" fuel direction to increase the engine speed.Before the engine gets to the new set speed, the compensation system starts to move the pilot valve plunger back to its center position and put the governor under stable control as follows.The oil above the power piston is connected to the upper side of the buffer piston and lower side of the pilot valve compensation land. As the power piston moves up the oil pressure moves the buffer piston down and increases the compression of the lower buffer piston spring. The force of the spring works against the buffer piston movement and this results in a small increase in oil pressure on the upper side of the buffer piston. This higher pressure is directed to the lower side of the pilot valve compensation land and makes a force to push the pilot valve plunger up toward its center position. This stops the flow of pressure oil to the lower side of the power piston and movement of the piston is stopped.As the pilot valve plunger is returned to its center position and the power piston movement is stopped, there is oil leakage through the needle valve orifice. This lets the oil pressure above and below the pilot valve compensation land become equal and the pilot valve plunger movement is stopped and the engine speed is returned to a stable condition. As the pressure above and below the compensation land become equal, the buffer springs return the buffer piston to its center position. An increase or decrease in engine load will give the similar governor movement as an increase or decrease in governor speed setting.Shutdown
The limit/shutdown pilot valve is located in the pump oil pressure supply line to the ballhead pilot valve. When the engine shutdown system is activated,