What is the operating principle of automobile air conditioning compressor

As a perennial car user, it is important to understand the operating principle of car air-conditioning compressors.

The season of using cold air conditioning is coming: how to use the A/C switch and the operating principle of the car air conditioning system. These two points are necessary for car users to understand some knowledge; especially the switching method of internal and external circulation, which is very effective in different modes. The ability of air purification and filtration will vary greatly. Let's talk about the air conditioning system of a car.

Fuel-powered automobile air conditioning system

The "power source" of the cold air-conditioning system is the compressor, and the role of this machine can be understood as driving the flow of refrigerant. Refrigerant is a chemical substance with extremely low boiling point, which will also evaporate into gaseous state at room temperature. The reason for air-conditioning refrigeration is to use the two forms of refrigerant conversion. First, the compressor provides driving force to push the refrigerant to the condenser. After cooling down, the refrigerant goes to the drying tank for water separation. At this time, the refrigerant is still in a low-temperature gaseous state. Under the continuous push of the compressor, the refrigerant will reach the expansion valve. At this time, the refrigerant will become a low-temperature liquid, and finally the refrigerant will reach the "evaporator".

"Evaporation heat absorption" is the most common physical phenomenon. As the saying goes, "snow does not become cold and snow becomes cold". The principle is that the evaporation of snow absorbs the heat in the air to cool down during the chemical process. In the same way, the refrigerant returns to the normal temperature environment after reaching the position of the evaporator. At this time, the refrigerant with a very low boiling point will quickly evaporate and absorb the heat of the evaporator during the evaporation process. The evaporator that becomes cold becomes a "cooling box" for warm air. The hot air is blown through the evaporator by the blower to cool down, and after being sent into the car, it is called "cold air". The operating principle of the automobile air-conditioning system is like this. The refrigerant circulates back and forth under the driving force of the compressor, and the refrigeration is practiced with changes in form. The key point-where does the power of the compressor come from?

The circulation of refrigerant in the pipeline requires a lot of driving force to achieve, and its normal operation power often requires 2~3kw, which is 2.72~4.08PS (commonly known as horsepower) when converted into horsepower. Such a large power cannot be driven only by the battery of the vehicle. For a fuel vehicle, only the engine can bring such a large driving force; therefore, the compressor of the car air conditioner must be connected to the crankshaft of the engine, and it is driven by the operation of the crankshaft. Synchronous operation. This is the reason why the use of automobile air-conditioning will increase fuel consumption, because the compressor takes up 2~4 horsepower of the engine. When the vehicle is idling, it needs to increase the speed (increase the fuel injection) to compensate for these horsepower in order to stabilize the idling speed without stalling.

Key point: In order to save fuel, there is no need to use compressors when not using air conditioners or heating air conditioners; car heaters use "hot water" of high-temperature coolant to warm the wind water tank, and use water heating to heat cold air. A system does not increase the operating load of the engine, so fuel consumption will not increase. So how to turn off the compressor in these two states? The A/C button on the car plays this role. When the A/C switch is not lit, the compressor separates the pulley from the compressor. At this time, the pulley is idling with the engine crankshaft. After the A/C switch is turned on, the one-way electromagnetic clutch of the compressor is energized. After the passage, the electromagnetic clutch will transfer the torque of the pulley to the compressor to run, and the engine will start to increase power consumption.

The above content is the operating principle and structural characteristics of the car air conditioner. For the user, only need to understand and master the switching of the A/C switch. The second is the switch between the inner and outer circulations. The outer circulation directly introduces the outside air into the car without filtering, but it will also undergo cooling treatment. The inner circulation is to filter the air through the filter element to remove impurities, or filter some germs through the PM2.5 filter element and then send it into the car; the outer circulation can be used on the high-speed sections with good air quality, otherwise, the inner circulation needs to be used.

Note: The functions of the internal and external circulation systems of electric vehicle air conditioners are the same as those of fuel vehicles. The difference is that the compressor is changed from an internal combustion engine to an electric compressor driven by electricity. The operating principle is the same but the power source is different. Secondly, there are differences in the heating and air-conditioning system. Because electric vehicles do not have an internal combustion engine, there will be no "high-temperature waste heat" of the coolant that can be used. Therefore, the coolant can only be heated by electric heating, and then the circulating heating water tank can be used to heat the air. Electric vehicles use warm air to consume a lot of electricity, while cold air is the opposite. This is the characteristic of the air-conditioning system of the two vehicles.