It's hot in summer, and you can't drive without air conditioning. Some car owners know little about car air conditioners, and during operation they may encounter various problems, some of which are related to operation, and some are related to operation of air conditioners.
In fact, many problems can be easily solved if you know a little about car air conditioners. So, today we will share some knowledge related to car air conditioners.
1. How does a car air conditioner work?
Strangers need to get to know each other first time they meet. If we want to understand an automobile air conditioner, we must also have a general understanding of how it works.
The working principle of a car air conditioner can actually be described in very simple terms, that is, compressor makes refrigerant circulate in air conditioner piping, part of air conditioner piping is inside car, and other part is outside car. The refrigerant turns from liquid to gas in evaporator inside car, evaporates and absorbs heat to create a low temperature, then gaseous refrigerant is compressed by compressor, liquefied in external condenser, releases heat and becomes liquid again, and then enters car again gasification absorbs heat. Thus, heat in car is gradually transferred to outside, and inside of car naturally becomes cooler.
Therefore, if you want to improve cooling effect of car, you should keep condenser outside car and evaporator inside car clean to improve heat exchange efficiency.
2. Types of automotive air conditioner compressors
Although car compressors look similar, differences between them are quite large. At present, air conditioning compressors in domestic vehicles can be divided into two types according to their design: reciprocating compressor and scroll compressor. According to working mode, it can be divided into fixed displacement compressor and fixed displacement compressor. Reciprocating compressors are very similar to car engines, they use reciprocating pistons to suck in and compress refrigerant. The mechanical loss of reciprocating compressor is relatively large, but its design can realize variable displacement function after a special design. Therefore, now many cars are equipped with piston-type variable displacement compressors. The mechanical loss of scroll compressor is very small, but displacement is fixed. At present, almost all fixed displacement compressors on family cars are scroll type, simple structure and low loss.
3. A/C compressor not running all time
For fixed displacement compressors, compressor does not run all time when air conditioner is on, but runs for a while and stops for a while. Because if compressor runs all time, liquid refrigerant will continue to evaporate and absorb heat in evaporator, and there will be a lot of condensate on surface of evaporator, at temperatures close to zero, condensate will freeze and completely block evaporator. , air conditioner will not blow.
So there is a temperature sensor on A/C evaporator, and when evaporator temperature approaches icing temperature, compressor clutch is disengaged. This phenomenon is most pronounced when air conditioner is turned on in place. Standing outside car, sound of compressor electromagnetic clutch continuously turning on and off is clearly audible.
Sometimes when car body unexpectedly starts to move forward while driving, this is mainly due to fact that compressor is turned off. And after more than ten seconds, body of car suddenly seemed to pull, which is probably due to fact that compressor was turned on again.
4. Temperature control principle of "deceiver"
If your vehicle has a fixed displacement compressor, it is most economical to run A/C at lowest temperature.
Because this type of air conditioning system regulates outlet air temperature by controlling amount of mixed air. If you set a higher temperature, air conditioning system will send some of cold air into warm air water tank for heating and then mix with cold air so that air outlet temperature is not so low that it actually wastes some of cooling power. A variable displacement compressor can control temperature by reducing compressor's operating power.
Therefore For fixed displacement compressors, lowest temperature is most economical. Variable displacement compressor - higher temperature setting, more economical fuel consumption.(a small program has been added here, go to Dianchedi client to view it)