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What are the common faults and maintenance methods of car air conditioners

What are the common faults and maintenance methods of car air conditioners

Whenever the hot summer arrives, the air conditioner becomes one of the most frequently used components in the car. As the service life continues to increase, many car owners will find that the air-conditioning system occasionally has some minor problems of one kind or another, such as lack of fluorine. In fact, the reason for this situation is largely due to our inadequate care of our car. Next, Suzhou Zhongcheng New Energy Technology Co., Ltd. will give you a detailed introduction to some issues that need to be paid attention to during the use and maintenance of automobile air conditioning systems.


Whenever the hot summer arrives, the air conditioner becomes one of the most frequently used components in the car. As the service life continues to increase, many car owners will find that the air-conditioning system occasionally has some minor problems of one kind or another, such as lack of fluorine. In fact, the reason for this situation is largely due to our inadequate care of our car. Next, Suzhou Zhongcheng New Energy Technology Co., Ltd. will give you a detailed introduction to some issues that need to be paid attention to during the use and maintenance of automobile air conditioning systems.

1. In daily use, it is often checked

Next, let's take a look at how to test the air conditioning system of our car during daily use. Compared with professional repair shops, as general users, we have limited tools and time, so we can only check it through some conventional methods. Next, we will introduce you to several simple but effective troubleshooting methods for air conditioning systems.


The use of the condensate can be checked through the glass observation hole and the low-pressure pipeline


First of all, check whether the refrigerant is sufficient, which is what we usually call "fluorine deficiency". The use of the refrigerant can be checked through the glass observation hole on the liquid storage dryer in the engine compartment. If a large number of bubbles are generated in the observation hole after the air conditioner is started, it means that the refrigerant is insufficient. Another simpler method is to touch the low-pressure tube with your hands. If it feels cold to the touch and condensation occurs, you can basically determine that this part of the system is operating normally. However, if the air conditioning system is started for a period of time and it feels similar to the ambient temperature to the touch, it is likely to be fluorine-deficient.


While checking the above two items, we can also visually check whether the refrigerant is leaking. Since the oil and refrigerant in the compressor are mixed and transmitted in the entire air conditioning system, when the refrigerant leaks, part of the oil will inevitably be taken out, leaving oil traces at the leak. Therefore, we only need to check whether there are oil traces at the hoses and joints to determine whether the refrigerant is leaking. If oil traces are found, they should be dealt with as soon as possible.


Next, let's take a look at the power transmission part of the compressor. The electromagnetic clutch of the air-conditioning compressor is composed of a pressure plate, a pulley and an electromagnetic coil. When the power is turned on, current flows in the coil of the electromagnetic clutch, and the magnetized iron core generates suction, which adsorbs the iron on the end of the belt pulley, and drives the compressor shaft to rotate through the spring plate combined with the disc, so that the entire air-conditioning system is operated. When we turn off the air conditioning system, the power supply is cut off, the current in the electromagnetic clutch coil disappears, and the suction force of the iron core is also lost. The iron is returned under the action of the spring plate, and the compressor stops working. At this time, the compressor pulley is only affected by the engine. Drive and idling. Therefore, when we start the air conditioner and find that the electromagnetic clutch of the compressor is not working properly, it proves that the component has failed. This is also one of the main reasons why the vehicle air conditioning system cannot operate normally. So when we find the fault This part should be overhauled in time.


As a part of the air-conditioning transmission system, the compressor belt also requires us to regularly check its tightness and usage status. If the side that is in contact with the belt is found to be shiny, it means that the belt is likely to have slipped. In addition, you can press the inside of it with your fingers. If it can have a curvature of 12-15mm, it is normal. If the belt is shiny and the degree of curvature exceeds the specified value, the ideal cooling effect cannot be achieved. You should correct it in time. The part is replaced.


Finally, let's take a look at the condenser, which is also easily overlooked. The location of the condenser is generally at the front end of the car. It uses the air blown from the front of the car to cool down the refrigerant in the pipeline. The mechanism of this component is that the high-temperature, high-pressure liquid refrigerant from the compressor passes through the condenser and becomes a medium-temperature and medium-pressure state. The refrigerant passing through the condenser itself is a very effective cooling process. If the condenser fails, it may cause pipeline pressure imbalance and malfunction of the air-conditioning system. The structure of the condenser is similar to the radiator, which is designed to increase the contact area so that the air-conditioning refrigerant can achieve maximum heat exchange in the smallest possible position.


Therefore, regular cleaning of the condenser is also very necessary for the overall effect of air-conditioning and refrigeration. We can visually observe whether there are bent warped pieces or foreign objects on the front of the condenser. If available, use pliers to straighten the warped pieces or use a stiff brush to straighten them. The foreign body is removed. In addition, if oil stains are found on the condenser, it is very likely that a leak has occurred. However, as long as the vehicle does not crash during normal driving, the condenser will basically not have serious failures.


2. Working principle and precautions for use

Although the air conditioning structure of different vehicles is different, the working principle is basically the same. Simply put, it is to use refrigeration to lower the temperature in the car to achieve a comfortable ambient temperature for the driver and passengers. Under normal circumstances, heat always flows from the high temperature area to the low temperature area, and the purpose of the air conditioner is to transfer the heat in the air in the car to the higher temperature atmosphere, so that the temperature in the car has been maintained at a lower temperature. This is a reverse cycle of heat flow, so it needs to be done with the help of a refrigeration mechanism.


The refrigerant in automobiles mainly adopts compression refrigerant, which uses the principle of heat absorption by liquid refrigerant to achieve the purpose of cooling. The refrigeration system is mainly composed of four major assemblies: compressor, condenser, expansion valve and evaporator. The high-temperature and high-pressure refrigerant from the compressor enters the condenser through the high-pressure hose. Since the outside temperature of the vehicle is lower than the temperature of the refrigerant entering the condenser, most of the heat of the refrigerant in the condenser is removed from the outside of the vehicle with the help of the cooling fan. The air is taken away, condensing the high-temperature, high-pressure gas into a high-temperature, high-pressure liquid.


When the condensed high-temperature, high-pressure liquid flows through the throttle expansion valve, due to the throttling effect, the volume suddenly increases and the pressure drops, and it becomes a low-temperature, low-pressure mist that enters the evaporator and vaporizes under a certain pressure. When the refrigerant vaporizes in the tube, the temperature is lower than the circulating gas in the car outside the evaporator tube, so the heat in the air outside the tube is automatically absorbed, so that the temperature of the air flowing through the evaporator is reduced, and finally the effect of cooling and cooling is achieved. The vaporized refrigerant is sucked and compressed by the compressor, turned into a high-temperature, high-pressure gas, and then sent to the condenser through a high-pressure hose, thus completing the entire thermal cycle of the refrigeration system.


Next, we talk about how to use the air conditioner correctly. In the eyes of most consumers, the use of air-conditioning systems does not seem to have any technical content, but as everyone knows, we can easily overlook some details. For example, in order to open the operation sequence, many people often keep the A/C, that is, the refrigeration button, always on for the sake of convenience, and do not turn off the wind speed switch first when the vehicle is stopped. In fact, this is not very theoretically speaking. specification.


If you don't want to be disturbed by sudden wind noise after starting, please reset the cooling button before turning off the car, and then turn off the wind speed completely. The order when turning on is exactly the opposite. You must turn on the wind speed button first, then turn on the A/C button, and adjust the temperature to the appropriate gear according to the temperature in the car and your needs. Of course, there are already many cars equipped with automatic air-conditioning systems, which is more convenient for operators. Just adjust the mode to automatic state, and then set the temperature value to be "isolated". What a scorching sun outside.


In addition, some careful consumers may find that when the air conditioner or cooling fan is turned on, the pointer on the idle speed indicator will jitter very slightly. In fact, this phenomenon is normal. You don’t have to worry about whether there is any problem with the vehicle, because all the power required for the operation of the air-conditioning compressor and cooling fan comes from the engine, which will cause the power output of the engine to split instantly, so it appears. The phenomenon that idling speed is temporarily unstable. However, this situation does not happen in all models. For example, in cars with larger displacement engines, the rated power required by the compressor and electronic fan is very small compared to the engine power value, so when they start It will not significantly affect the power output of the engine, so the pointer on the tachometer will not swing up and down.


3. What problems should be paid attention to when adding fluoride

If the refrigerant is missing, it is of course essential to add fluoride to the air-conditioning system in order to prevent yourself from doing a "sauna" in the car during the unbearably hot summer. Next, let's analyze what we can do to supervise the operator during the process of adding refrigerant.


At present, most passenger cars running on the road use R134a refrigerant. I believe that consumers who have been driving for a long time still remember the refrigerant R12, so what are the differences between it and R134a, and why almost all vehicles have now eliminated the refrigerant R12? Below, let's take a look at these two refrigerants in detail. The refrigerant used in automobile air-conditioning compressors is represented by the English letter "R" internationally. If there is a two-digit number after R, it is freon derived from methane, such as R12. If R is followed by a three-digit number, it is expressed as a Freon derivative of ethane, propane, butane series, such as R134.


The R12 refrigerant that has been used a few years ago has colorless, non-irritating odor; under normal circumstances, it is not toxic and has no direct harm to the human body; it does not burn or explode; it has good thermal stability and does not decompose at room temperature. . However, when it comes into contact with an open flame and the temperature is higher than 400℃, it will produce poisonous gas and phosgene that have a violent effect on the human body. In addition, it is also a kind of refrigerant that is easy to manufacture, abundant in raw materials, relatively low in price, and recyclable. However, it has a certain destructive effect on the atmospheric ozone layer, so it has been gradually replaced by the R134a currently used.


Since 1996, R134a, which is more environmentally friendly, safer, and more stable, has been used as refrigerants for automotive air conditioners. Because the physical characteristics of the refrigerants R134a and R12 are different, the functional components and compressors related to the two refrigerant cycle systems Each oil has its own characteristics. Therefore, it is absolutely forbidden to exchange the two refrigerants, even using a small amount will cause the refrigerant to precipitate and damage the compressor. Vehicle owners can generally distinguish by observing the warning signs affixed to the car's air-conditioning system. The warning signs for R134a air-conditioning systems are usually "R134a USE ONLY."


Next, let's talk about the process of adding fluoride. If the average consumer sees the fluoride bottle and the pressure gauge set, will they have an idea? "Forget it, let a professional maintenance technician do such a complicated project." Yes, we don't want to repeat the complicated precautions and various data parameters in the process of adding fluoride here. Introduce a few points to note:


1. Before adding fluoride, you should check the entire air-conditioning system for leaks by visual inspection. The specific method has been mentioned in the first half of this article.

2. If there are no leaks found by visual inspection, further testing should be done by vacuuming. The entire process of vacuuming generally takes more than 10 minutes. Therefore, if you open the fluorine tank as soon as the technician comes up while adding fluoride, the editor recommends that you better change the ground immediately.

3. If no leaks are found after the final inspection, you can start adding fluorine with confidence. If there are leaks, you should deal with the malfunctioning parts first.

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