ROD-CARBURETOR CONTROL 1115031 - Caterpillar

Illustration 1 g03720997
(A) Standard fan
(B) Optional reversing fan
(1) Fixed displacement gear pump
(2) Oil cooler outlet
(3) Hystat charge
(4) Flow control valve
(5) Makeup valve
(6) Fan drive gear motor
(7) Relief valve
(8) Fan reversing valve
(10) Makeup valve
(11) Flow control valve The hydraulic fan system contains fixed displacement gear pump (1) and fixed displacement fan drive gear motor (6). The hydraulic fan system also includes either the standard fan (A) or reversing fan (B).Standard Fan
Illustration 2 g03721013
(A) Standard fan
(4) Flow control valve
(5) Makeup valve
(6) Fan drive gear motor When the engine is started, hydraulic oil is drawn from the tank by fixed displacement gear pump (1). Flow control valve (4) is controlled by the engine ECM. The speed of the fan motor depends on the amount of flow that is allowed through flow control valve (4). The control of the fan speed is based on the value of the following conditions:
Air inlet temperature
Hydraulic oil temperature
Engine coolant temperature
Illustration 3 g03831813
Standard demand fan
(12) Hydraulic oil temperature sensor
(13) Machine ECM
(14) Demand fan solenoid
(15) Engine ECM
(16) Air inlet temperature sensor
(17) Engine coolant temperature sensor Engine ECM (15) controls the command to demand fan solenoid (14). The engine ECM uses input from the three temperature sensors in order to determine the command. Air inlet temperature (16) and engine coolant temperature (17) are communicated to engine ECM (15) directly. Information from the hydraulic oil temperature sensor (12) is sent through machine ECM (13) to engine ECM (15). Flow control valve (4) closes in order to restrict the flow of oil through the flow control valve. When the flow of oil through the flow control valve is restricted, oil must flow through fan drive gear motor (6). Thus causing the fan motor to turn faster. The speed of the fan depends on the amount of current that is sent to the demand fan solenoid valve.When the machine requires less air flow, the engine ECM will increase the amount of electric current to demand fan solenoid (14) in order to shift the flow control valve more open. When the flow of oil through the control valve is increased, the flow of oil from the hydraulic fan pump will flow through the flow control valve instead of flowing to the fan motor. Thus causing the fan motor to turn more slowly. The speed of the fan depends on the amount of current that is sent to the demand fan solenoid valve.Makeup valve (5) prevents cavitation of the fan motor during deceleration.Reversing Fan (If Equipped)
Illustration 4 g03831903
(B) Reversing fan (forward)
(C) Reversing fan (reverse)
(6) Fan drive gear motor
(7) Relief valve
(8) Fan reversing valve
(9) Flow control valve
(10) Makeup valve
(11) Flow control valve
(12) Hydraulic oil temperature sensor
(13) Machine ECM
(14) Demand fan solenoid
(15) Engine ECM
(16) Air inlet temperature sensor
(17) Engine coolant temperature sensor
(18) Reversing fan switch
(19) Reversing fan solenoid The machine can be equipped with a reversing fan. The cooling capacity of the machine is diminished when any of the following components are obstructed with debris:
The radiator
The hydraulic oil cooler
The air-to-air aftercooler (ATAAC)
The screens in the enclosure doorsFlow control valve (11)