VALVE GP-MAIN CONTROL 4202243 - Caterpillar

Illustration 1 g03674396
Illustration 2 g03674398
(1) Hydraulic oil cooler
(2) Electrohydraulic controls
(3) Implement Valve
(4) Lift Cylinder
(5) Tilt Cylinder
(6) Hydraulic Tank
(7) Return flow filter
(8) Implement controls The 980M and 982M Wheel Loaders are electrohydraulically controlled. The machine uses hydraulic power that is controlled by electronics to move the actuators. The electrohydraulic system is composed of the following systems: the main hydraulic system, the pilot hydraulic system, the implement electronic control system, the kickout system and the hydraulic fan system.The hydraulic tank is common to all of the systems.The 980M and 982M Wheel Loaders are equipped with a proportional priority pressure compensated 3PC electrohydraulic implement system. The 3PC electrohydraulic system will sense a demand for a flow change and the implement pump will upstroke or destroke to provide the demanded flow. The 980M and 982M Wheel Loaders are equipped with a full return flow filtration system. The return oil from the implement valve, the steering valve, and the optional axle oil cooling system flows through the return oil filter in the hydraulic tank. A new load sense relief/purge valve limits the maximum load signal pressure sent to the implement pump allowing a constant purge in the load signal circuit. With the constant purge system, the signal duplication valve and signal relief valve have been eliminated. The resolver valves have been eliminated and the anti-drift valves are now pilot operated.The implement electronic control system consists of the following components: solenoid valve (hydraulic lockout), solenoid valves (pilot proportioning), implement piston pump, implement ECM, joystick control and control levers, switches and sensors.The main hydraulic system consists of the following components: main control valve, tilt cylinder, lift cylinders, load sensing signal relief valve and implement piston pump. The pilot system consists of the following components: the control manifold, pressure reducing valve, hydraulic oil filter and hydraulic pump (brake, pilot, fan). The pilot control actuators are attached to the main control valve. The actuators control the shifting of the stems. Also, the main control valve is equipped with a shuttle valve (ball resolver) and a pressure reducing valve (lowering control). The shuttle valve and the pressure reducing valve are used to supply pilot oil to the pilot control actuators allowing the work tool to be lowered with a dead engine.The kickout system consists of the following components: pressure reducing valve, implement ECM, control levers or joystick control, lift linkage position sensor and tilt linkage position sensor.The hydraulic fan system is standard on all 980M and 982M Wheel Loaders. The hydraulic fan system is an on-demand fan control system. As the need for more cooling arises, the fan system supplies more air flow through the radiator. The output of the hydraulic fan system is used to meet different cooling requirements during high ambient conditions or a light work application. For additional information about the hydraulic fan system, refer to the Systems Operation, "Hydraulic Fan System".The ride control system consists of the following components: lift cylinders, ride control valve, dual accumulators and power train ECM. The dual accumulators and a balancing