1. Importance of overheat protection mechanism
It is very necessary to equip Car Air Conditioner Heater Heating Element with overheat protection mechanism. During the operation of the car, its electrical system and environmental conditions are complex and changeable. The heating element generates heat when it continues to work. If there is no overheat protection mechanism, the temperature of the heating element may continue to rise once an abnormal situation occurs, such as a failure of the cooling system, long-term high-load operation or excessive ambient temperature. This excessive heat accumulation will not only reduce the performance of the heating element itself and cause it to fail prematurely, but may also cause serious safety hazards, such as fire or damage to other components in the car air conditioning system. For example, excessively high temperatures may melt nearby plastic pipes or damage the insulation layer of wires, thereby affecting the normal operation of the entire car air conditioning system.
2. Common overheat protection methods
Car Air Conditioner Heater Heating Element usually uses a variety of methods to achieve overheat protection. One of the common methods is to use a thermistor. Thermistors have the characteristic that the resistance value changes with temperature, especially negative temperature coefficient (NTC) thermistors, whose resistance value drops rapidly with increasing temperature. In the circuit of the heating element, a suitable thermistor is connected in series or in parallel. When the temperature of the heating element rises to a certain threshold, the change in the resistance of the thermistor will be detected by the control chip in the circuit. According to the preset program, when the control chip detects that the resistance of the thermistor reaches the value indicating overheating, it will cut off the power supply circuit of the heating element, thereby stopping heating and preventing the temperature from rising further.
Another way is to use a temperature fuse. A temperature fuse is a one-time protection device. It is installed near or inside the heating element. When the ambient temperature exceeds its rated fuse temperature, the metal wire inside the fuse will melt, thereby disconnecting the circuit of the heating element. This method is simple and direct, and can effectively protect the heating element and the entire system when the overheating situation is more serious.
3. Set temperature of overheat protection mechanism
The set temperature of the overheat protection mechanism is a key parameter. The setting of this temperature requires comprehensive consideration of many factors. First of all, the material properties of the heating element itself should be considered. Different heating element materials (such as the material of the resistance wire) can withstand different maximum temperatures. Generally speaking, in order to ensure the long-term stable use of the heating element, the set temperature will be lower than the critical temperature of its material. For example, for some common resistance heating materials, the set temperature of the overheat protection mechanism may be between 180 - 220 ° C. At the same time, the overall operating environment and safety requirements of the automotive air-conditioning system should also be considered. If the set temperature is too high, it may cause potential risks to other components in the system; if the set temperature is too low, it may cause the heating element to stop working frequently, affecting the normal heating function of the air conditioner.
4. Collaboration with the automotive air-conditioning system
The overheat protection mechanism works with other parts of the automotive air-conditioning system to ensure the safe and efficient operation of the entire system. When the overheat protection mechanism is triggered and the heating element stops working, the control unit of the automotive air-conditioning system will receive the corresponding signal. In this case, the system may take a variety of measures, such as reducing the speed of the blower to reduce the need for heat dissipation, and displaying a fault prompt of the air-conditioning heating system on the dashboard to remind the driver to check. In addition, once the temperature of the heating element drops to a safe range, the overheat protection mechanism will allow the heating element to work again, but the system will monitor the working status of the heating element more closely to prevent overheating from occurring again. This collaborative working mechanism helps to maintain the normal heating function of the car's air-conditioning system as much as possible while ensuring safety.
