LINES GP-BOOM CYLINDER 3471200 - Caterpillar

Hydraulic Pump Flow and Pressure Control System
Illustration 3 g03814506
Pump compartment (26) Fan pump (27) Pilot pump (28) Front pump (30) Rear pump (79) Delivery line (rear pump) (80) Delivery line (front pump)This machine is driven and controlled by the following systems.
The main hydraulic system controls the cylinders, the travel motors, and the swing motor.
The pilot hydraulic system supplies oil to the main control valve, the swing brake, the travel motors, and the pilot operated control circuits.
The electronic control system controls the outputs of the engine, pumps, and main control valve.
The separate cooling system supplies oil to the fan motors in order to cool the hydraulic oil temperature.The main hydraulic system delivers oil flow from rear pump (30) and front pump (28) in order to control the following systems: bucket system, stick system, boom system and the swing system.
Illustration 4 g03814516
Main control valve (41) Stick IMV section (49) Main relief valve (rear pump)(stick and right travel) (54) Main relief valve (front pump)(boom, bucket, and left travel) (65) Bucket IMV section (74) Boom IMV section (78) Main control valve center manifoldMain control valve (4) is an Adaptive Control System (ACS) valve. The ACS valve is an electronically controlled hydraulic system that adjusts performance through software. The main control valve consists of several Independent Metering Valves (IMV), a center manifold, and two end plates. Each IMV section contains two, pump-to-cylinder (P-C) proportional hydraulic modulation valves (PHMV) and two, cylinder-to-tank (C-T) PHMV's which are electrically controlled. The machine software adjusts pump-to-cylinder and cylinder-to-tank ports to provide optimum efficiency and control for different front linkage weights and operating conditions. The end plates contain valves that are used for the automatic warm-up procedure.For more information concerning the ACS main control valve, refer to Systems Operation, "Main Control Valve".Front pump (28) and rear pump (30) are variable displacement piston pumps. The performance of both pumps is equal, and the pumps are arranged in series. The output flow is electronically controlled by one power shift pressure PRV and two negative flow control PRV's.Front pump (28) is directly connected to the engine by a flexible coupling. Rear pump (30) is connected to the front pump. The front pump and the rear pump deliver oil to main control valve center manifold (78). The rear pump delivers oil to the right travel control valve, the stick independent metering control valve, and the swing control valve. The front pump delivers oil to the left travel control valve, the bucket independent metering control valve, and the boom independent metering control valve. Pilot pump (27) is a gear pump that supplies oil to the pilot hydraulic system. Pilot pump (27) is mechanically connected to fan pump (26) through a splined shaft. All engine output is used to drive these four pumps.As the load pressure increases during working conditions, the main pumps increase the delivery pressure and the pumps decrease the flow rate. The hydraulic horsepower remains constant even though the delivery pressure and the flow rates change. The hydraulic horsepower is identical to the