CONTROL GP-HANDLE 4913721 - Caterpillar

Illustration 1 g01271604
Rear view of engine
(1) Turbocharger
(2) Accumulator
(3) Check valve
(4) Oil supply tube Accumulator (2) provides lubrication to the turbocharger bearings during shutdown when the engine oil pressure is reduced but the turbocharger wheels are still rotating. This helps increase the service life of the turbocharger (1).After start-up, engine oil pressure rises and pressurized oil from the engine block flows upward through oil supply tube (4). The oil flows through check valve (3) to accumulator (2).
Illustration 2 g01271636
Inside of the accumulator
(5) Piston
(6) Chamber
(7) Valve The accumulator has a chamber (6) that is filled with nitrogen gas. Valve (7) is used to fill the chamber and the valve is used to measure the pressure in the chamber.Piston (5) is moved by differential pressures. Nitrogen gas in the lower part of the chamber pushes up on the piston. During engine operation, the engine oil pressure becomes greater than the nitrogen gas pressure. Pressurized engine oil pushes the piston downward. The upper portion of the chamber fills with oil until the pressure of the oil and the pressure of the nitrogen gas are equalized.The piston's outer diameter is sealed in order to prevent the flow of gas or oil between the upper and lower portions of the chamber. The upper portion of the chamber remains filled with oil during engine operation.When the engine shuts down, the pressure of the nitrogen gas becomes greater than the pressure of the engine oil. The piston is pushed upward and the oil is forced out of the upper chamber.The oil supply line has a check valve that closes the oil passage from the cylinder block. This prevents the oil from draining into the cylinder block. The oil is directed to the turbocharger. After the turbocharger bearings are lubricated, the oil drains into the crankcase through the rear housing.Oil from the accumulator continues to lubricate the turbocharger until the nitrogen gas pushes the piston to the fully upward position and the supply of oil from the chamber is exhausted.