RADIATOR & HYD OIL COOLER AS 1428879 - Caterpillar

Illustration 1 g06323900
(1) Fan pump
(2) Hystat charge
(3) To oil cooler
(4) Makeup valve
(5) Flow control valve
(6) Demand fan valve
(7) Reversing valve
(8) Fan motorThe hydraulic fan system contains fixed displacement gear pump (1) and fixed displacement gear motor (8). The speed of the fan motor depends on the amount of flow that is allowed through demand fan valve (6). The engine ECM uses input from three temperature sensors to determine the flow:
ATAAC outlet temperature
Hydraulic oil temperature
Engine coolant temperatureWhen the engine is started, hydraulic oil is drawn from the tank by fixed displacement gear pump (1). Using data from the temperature sensors, the ECM sends a command to valve (6). If the fan does not need to turn at max RPM, the ECM will open valve (6) to allow oil to bypass the motor. The speed of the fan depends on the amount of current that is sent to valve (6).Reversing solenoid (7) is also controlled by the engine ECM. When the reversing function is desired, the Engine ECM energizes reversing solenoid (7). The reversing function can be activated manually or through the automatic configuration option.The following features can be configured:
"Enable/Disable"
"Purge cycle duration"
"Purge cycle interval"Refer to the OMM for your product for more configuration information.The oil that leaves the fan motor travels to the hystat pumps to provide charge oil (2). From the pumps, the same supply of oil travels to the hystat motors to provide charge oil, flushing, and cooling.The fan motor also distributes oil to the oil cooler through passage (3).