The inspection of automotive air conditioning equipment

The automotive air conditioning device mainly consists of the following components: automotive air conditioning compressor, condenser, throttling expansion structure, evaporator, inlet pipe, pipeline, and exhaust pipe.

Automotive air conditioning compressor: It is the heart of the automotive refrigeration system and the power source that drives the continuous circulation of refrigerant in the refrigeration system Exhaust pipeline: connecting pipeline between compressor and condenser, high-pressure pipe. The refrigerant flows from the compressor to the condenser Condenser: A heat exchange device that releases high-temperature and high-pressure superheated refrigerant vapor from the compressor and releases heat to the air outside the condenser through metal wall tube fins, thereby condensing the superheated gaseous refrigerant into high-temperature and high-pressure liquid

Liquid inlet pipe: condenser and expansion saving tissue connecting pipeline, high-pressure pipe. Refrigerant flows from the condenser to save swelling tissue

Throttling expansion structure: It plays a role in saving and reducing pressure in the entire system, and is the boundary component between high and low pressure in the entire system Evaporator: It is a low-temperature and low-pressure liquid refrigerant that has been saved through the expansion saving structure. During this process, it absorbs heat and vaporizes to achieve refrigeration Suction pipeline: The connecting pipeline between the evaporator and the compressor. The refrigerant flows from the evaporator to the compressor

Inspection of Automotive Air Conditioning Devices

1. Fixation Inspection of Refrigeration Hoses

1.1 The pipeline should be deburred and protected with a protective sheath in the area where it passes through the cutting edge.

1.2 The refrigerant hose should be fixed with clamps and ties, with a fixed distance of less than 600mm. When laying the pipeline, it should avoid hot parts by 150mm, and the distance between it and other parts should be greater than 40mm

2. Function inspection of air conditioning unit

2.1 Air conditioning switch function

The air conditioning can be turned on or off normally.

2.2 Function key detection on the air conditioning controller

Air volume selection: Adjust the air volume selection switch to detect changes in air volume.

Temperature control selection: Adjust the air volume selection switch. When it is placed in the off position, you can feel that the air outlet only supplies air without cooling

3. Detection of indicator light on the air conditioning controller

When the power is turned on, the air volume switch is placed in the open gear (any gear of the third gear wind speed), and the temperature control switch is placed in the open gear, the corresponding operation indicator light lights up.

4. Pressure maintenance function detection

The wiring of the pressure switch was manually disconnected. It was found that the compressor clutch was disconnected due to power outage, refrigeration was stopped, and the fan was supplying air normally.

. (Pay attention to wiring restoration after testing)

5. Detection during refrigeration operation

There is a significant temperature difference at the air inlet and outlet of the air conditioner. The observation window shows no significant bubbles (a small amount of bubbles is allowed when the environmental temperature is higher than 35 ℃), and the drainage of the air conditioning drainage pipe is normal

Pressure detection at the inlet and outlet of the air conditioning compressor (refer to the ambient temperature of 20-35 ℃)

Low pressure (normal value): 0.6~2.5 kgf/cm2

High pressure (normal value): 13~2.4 kgf/cm2

6. Inspection of refrigeration dose:

(1) Select an engine with a temperature above 20 ℃, operate the engine at low speed, set the temperature control switch to the coldest position, set the wind speed to the maximum position, and set the intake control switch to the inner circulation position, Turn on the air conditioning switch (A/C) and operate the engine at a speed of 1500r/min for about 5 minutes. Then, investigate the refrigerant activity through the sight glass

(2) Investigation of the sight glass of the dry liquid storage filter:

1. Moderate refrigerant storage: the hole is clear and clear, and there are no bubbles when the speed is stable. Occasionally, bubbles appear when the speed changes, and the enclosed air conditioning bubbles immediately, and then gradually disappear.

. There is a temperature difference on both sides of the inlet and outlet, with high pressure side heating and low pressure side cooling 2. Excessive refrigerant filling: The temperature difference between the high and low pressure sides is significant, and no bubbles can be seen. After closing the air conditioning, there are still no bubbles present, and the remaining refrigerant should be discharged

3. Lack of refrigerant stock: bubbles and constant foam. The cause should be identified and refrigerant should not be added casually

4. There is air in the refrigerant: there are bubbles and foam flows continuously, and there are many foam 5. Severe shortage of refrigerant: see a series of bubbles, with almost no temperature difference between high and low pressure sides 6. Completely free of refrigerant: no bubbles can be seen, and there is no temperature difference between high and low pressure 7. Excessive refrigerant oil: There are striped oil stains on the glass of the investigation hole