1. Structure and principle of automobile air-conditioning and refrigeration system
1. Air-conditioning pipeline: It is made of aluminum hard pipe and rubber hose, which is connected to the various parts of the refrigeration system. part.
2. Refrigerant: The vaporization of the refrigerant in the evaporator absorbs the heat of the air in the cabin to achieve refrigeration, and the condensation in the condenser releases heat to the outside air
3. Evaporator: The low-temperature and low-pressure refrigerant liquid continues to evaporate and vaporize, absorb the heat of the air flowing through the evaporator, and cool the air in the cabin. The evaporator is arranged in the vehicle compartment and is usually supplied with air by a centrifugal fan.
4. Expansion valve: Throttle the high-pressure refrigerant liquid from the liquid storage dryer to reduce the pressure and reduce the temperature to form a low-temperature and low-pressure mist refrigerant, which is sprayed into the evaporator. The flow of refrigerant injected into the evaporator can be automatically adjusted according to the temperature of the refrigerant vapor at the outlet of the evaporator.
5. Liquid storage dryer: When the refrigeration system is running, it filters, dries, absorbs moisture and temporarily stores the liquid refrigerant. There is often a sight glass above it to observe whether the refrigerant charged is sufficient and whether the flow is normal (the refrigerant should be free of foam and flow smoothly).
6. Compressor: Driven by the engine, it continuously inhales the low-temperature and low-pressure refrigerant vapor generated by the endothermic vaporization in the evaporator, and after compression, it forms a high-temperature and high-pressure refrigerant vapor, which is discharged to the condenser, which is used for the refrigerant in the evaporator. Continued condensation and heat release in the condenser creates high pressure conditions. At the same time, it overcomes the circulating flow resistance of the refrigerant in the refrigeration circuit.
7. Condenser: The heat contained in the high temperature and high pressure refrigerant vapor discharged from the compressor is released to the outside air flowing through the condenser, and the refrigerant vapor is condensed into a refrigerant liquid with a certain degree of subcooling. Most of the condensers are arranged in front of the radiator water tank at the front of the car, and are cooled by the cooling fan and the windward airflow generated by the driving of the car.
Second, the working principle of automobile air conditioning compressor
1, Fixed displacement compressor
The displacement of the fixed displacement compressor increases proportionally with the increase of the engine speed, it cannot automatically change the power according to the cooling demand output, and the impact on engine fuel consumption is relatively large. Its control generally collects the temperature signal of the air outlet of the evaporator. When the temperature reaches the set temperature, the electromagnetic clutch of the compressor is released and the compressor stops working. When the temperature rises, the electromagnetic clutch is engaged and the compressor starts to work. The fixed displacement compressor is also controlled by the pressure of the air conditioning system. When the pressure in the pipeline is too high, the compressor stops working.
2, Variable displacement air conditioner compressor
The variable displacement compressor can be The set temperature automatically adjusts the power output. The air-conditioning control system does not collect the temperature signal of the air outlet of the evaporator, but controls the compression ratio of the compressor according to the change signal of the pressure in the air-conditioning pipeline to automatically adjust the air outlet temperature. In the whole process of refrigeration, the compressor is always working, and the adjustment of the refrigeration intensity is completely controlled by the pressure regulating valve installed inside the compressor. When the pressure at the high-pressure end of the air-conditioning pipeline is too high, the pressure regulating valve shortens the piston stroke in the compressor to reduce the compression ratio, which will reduce the refrigeration intensity. When the pressure at the high pressure end drops to a certain level and the pressure at the low pressure end rises to a certain level, the pressure regulating valve increases the piston stroke to improve the refrigeration intensity.
Three, the performance of the car air conditioner compressor is broken
The main manifestation of the car air conditioner compressor broken is that the air conditioner does not cool.
A simple way to judge is to see if the engine speed will increase when the AC switch of the air conditioner is turned on (you can look at the tachometer in the cab). If the engine speed increases after the air conditioner is turned on, it means the compressor control circuit Yes, if the engine speed does not rise, it means that the compressor control circuit is good, or the electromagnetic clutch of the compressor is broken.
There is another case where the engine speed increases and the compressor clutch also pulls in, but the air conditioner compressor locks up and is scrapped and broken. If the compressor is bad, it may be the refrigerant water or oil seal Well, it causes incompressible liquid to enter the compressor, causing damage to the compressor piston. However, this situation is not common, and most compressors do not work mainly because of electromagnetic clutches.
Fourth. Can the car air conditioner compressor be repaired?
The car air conditioner compressor can be repaired, it is recommended to ask professional maintenance personnel to test it Repair according to the actual situation.
Auto Air Conditioning Compressor Fault Detection and Repair
Auto Air Conditioning Compressor Abnormal Noise Maintenance The necessary equipment of the car, but many car owners and friends found abnormal noise of the car air conditioner compressor during driving. They don’t know what to do. How to repair it? What are the ways to repair the abnormal noise of the car air conditioner compressor?
Automobile air-conditioning compressor It plays a very important role in compressing and transporting refrigerant vapor in automobiles. The normal operation of automobile refrigeration system is also inseparable from its role. There are many reasons for the failure of automobile air conditioner compressors. As a high-speed rotating working part, the air conditioner compressor has a relatively high probability of failure. Next, we will introduce several common faults for you to solve easily.
1. The most common fault is abnormal sound
When the car air-conditioning compressor makes a strange sound during work, you need to pay attention, Don’t be careless, this is the most direct place of failure, so you must pay attention, the strange sound is because the electromagnetic clutch of the compressor is generally installed close to the ground, and often shifts from low speed to high speed under high load During operation, it will inevitably come into contact with rainwater and soil, and abnormal noise will occur when the bearing in the electromagnetic clutch is damaged.
First check the air conditioning belt, whether the installation screws are loose, whether the belt is oily, and whether the belt is worn. If there is a problem with the electromagnetic clutch, just replace the electromagnetic clutch instead of the clutch assembly. If it still can’t be solved, you need to continue to make further judgments.
2. Stuck at work
During the working process of the air conditioner compressor, the compressor is stuck sometimes, and the reason for the stuck Mainly due to poor lubrication. When there is often a lack of lubricating oil, it is necessary to pay attention, because serious abnormal noise may occur inside the compressor, and even cause the compressor to be worn out and scrapped.
When this happens, you should check for clutch slippage or a belt problem.
3. Compressor leakage
Refrigerant leakage is the most common problem in air conditioning systems. There are two types of compressor leakage, oil leakage and air leakage. The leaking part of the compressor is usually at the junction of the compressor and the high and low pressure pipes. The internal pressure of the air conditioning system is very high. There are pressure relief protection valves on the air conditioning compressors. The pressure relief protection valves are usually used for one-time use. After the pressure is released, the pressure relief valve should be replaced in time.
There are many reasons for the failure of automobile air-conditioning compressors. Generally, when a failure occurs, it is not recommended that you solve it by yourself. Requirements and operations should be noted. And good habits in daily use should also be developed, which is the best secret to ensure that your car air conditioner will last longer.
Abnormal noise maintenance of car air conditioner compressor Have some insurance!
