The working principle of automotive electronic fans
The automotive electronic fan is controlled by a thermostat or a thermal switch. It starts cooling when the engine coolant temperature reaches the preset upper limit and stops when it drops to the lower limit. At the same time, the air conditioning is turned on, which also triggers its operation.
Core working principle of
The core control mechanism of the automotive electronic fan is based on temperature sensing and circuit linkage, and mainly consists of the following links:
Youdaoplaceholder0 temperature triggers :
The thermal switch (usually installed on the water tank) monitors the coolant temperature in real time. When the water temperature rises to the preset upper limit (such as 90°C at low speed or 95°C at high speed), the switch connects the power supply and the fan starts.
When the temperature drops to the lower limit, the switch cuts off the power supply and the fan stops working.
Youdaoplaceholder0 air conditioning linkage :
When the air conditioner is turned on, the signals of the condenser temperature and refrigerant pressure will force the electronic fan to start to assist in heat dissipation.
Youdaoplaceholder0 control module and signal transmission
Youdaoplaceholder0 Electronic control unit (ECU) : Some models receive sensor signals through the ECU, make comprehensive judgments, and then send instructions to the fan control module (such as J293) to adjust the high and low speed gears.
Youdaoplaceholder0 Dual system independent control : The air conditioning system (J301) and the electronic fan system (J293) achieve coordination through signal interaction, but the heat dissipation logic still mainly relies on water temperature.
Youdaoplaceholder0 Mechanical structure and energy efficiency optimization
Youdaoplaceholder0 motor-driven : The fan is directly driven by a motor to rotate the fan blades, eliminating the need for traditional belt drive and reducing energy loss.
Youdaoplaceholder0 graded speed : The design of high and low speeds strikes a balance between heat dissipation requirements and energy consumption. The low speed meets daily heat dissipation needs, while the high speed responds to extreme working conditions.
The common reasons for the continuous operation of automotive electronic fans include cooling system failure, circuit component damage or sensor abnormality, etc. Youdaoplaceholder0, which can be specifically classified into six core issues: insufficient coolant, radiator leakage, thermostat failure, relay contact adhesion, radiator dust accumulation, and water temperature sensor damage.
Youdaoplaceholder0 cooling system failure
Youdaoplaceholder0 Insufficient coolant : When the coolant level is too low, the engine cannot dissipate heat effectively, and the electronic fan will keep running to assist in cooling. Coolant needs to be replenished to the standard level in a timely manner.
Youdaoplaceholder0 water tank leakage : The water tank is damaged or the rubber hose is loose, causing coolant leakage, which leads to a decrease in heat dissipation efficiency and triggers the fan to keep working. It is recommended to inspect and repair the leakage point.
Youdaoplaceholder0 thermostat failure : A faulty thermostat can cause poor circulation of coolant, abnormal increase in engine temperature, and the fan may run for a long time at this time. The thermostat needs to be replaced to restore the circulation function.
Youdaoplaceholder0 circuit and sensor failure
Youdaoplaceholder0 water temperature sensor damage : When the sensor fails to accurately detect water temperature, it may continuously send high-temperature signals, causing the fan to misjudge its operation. The sensor needs to be replaced.
Youdaoplaceholder0 relay contact adhesion : Due to erosion and adhesion of the relay contacts, the circuit cannot be disconnected, and the fan will continue to be powered on and operate. The relay needs to be repaired or replaced.
Youdaoplaceholder0 Circuit fault : A short circuit or open circuit in the control circuit of the electronic fan may cause abnormal signals. It is necessary to check and repair the wiring harness connection.
Youdaoplaceholder0 other factors
Youdaoplaceholder0 Dust accumulation on the radiator : Dust accumulation on the surface of the radiator will reduce the heat dissipation efficiency, and the fan will need to work for a longer time. Regular cleaning can prevent this problem.
Youdaoplaceholder0 Air conditioning on or transmission oil temperature too high (for automatic transmission models) : When the air conditioning is running or the transmission oil temperature is abnormal, the fan may continue to operate to assist in cooling. If the air conditioner still operates after being turned off, it is necessary to check for faults.
Youdaoplaceholder0 special circumstances statement :
It is a normal phenomenon for the fan to run briefly after the engine is turned off (to help dissipate the residual heat).
If the water temperature is normal but the fan keeps rotating, the temperature control switch or relay should be checked first.
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