Illustration 1 | g06611625 |
Fan Control (1) Machine ECM (2) Display (3) Hydraulic oil temp sensor (4) Engine ECM (5) ATAAC temp sensor (6) Coolant temperature sensor (7) Fan solenoid |
Note: The blue lines in the above illustration indicate an input signal. The red lines indicate an output signal. The green and yellow lines indicate CAN communication. The arrowheads on the end of the lines indicate the direction of communication.
Note: The above illustration shows the general layout of the steering system with components and wire connectors. Refer to the machine electrical schematic for detailed wiring information.
Engine ECM (4) monitors input signals from the following devices to control fan solenoid (7):
- Hydraulic oil temperature sensor (3) via machine ECM (1)
- ATAAC air temp sensor (2)
- Engine coolant temp sensor (4)
Machine ECM (1) receives inputs from hydraulic oil temperature sensor (3). The machine ECM transmits this information to engine ECM (4) via CAN lines.
Engine ECM (4) controls fan speed through fan solenoid (7), which is mounted on the fan motor. Once the engine ECM calculates the target fan speed, the ECM generates a proportional output signal to the solenoid.
The signal sent to fan solenoid (7) is inversely proportional to the fan speed. The greater the output signal, the slower the speed of the fan. The minimum and maximum solenoid currents can be adjusted with the AVSpare ET software.
Software in engine ECM (4) contains the fan control logic. This logic uses an open-loop strategy for fan speed control.
The fan control logic compares the temperature values from the sensors to the programmed set points. When the temperature values are less than the corresponding set point value, engine ECM (4) operates the fan at minimum speed. If the temperature value of a monitored parameter exceeds the set point, the engine ECM increases the fan speed.