Just before the summer season, specialized car services dealing with the air conditioning system in vehicles are under siege. Driving a vehicle on hot days certainly affects the comfort of the truck driver, but it also has a significant impact on safety.
Studies conducted in high temperature conditions among bus drivers indicate, similarly to industrial psychology, that high temperature can reduce the excitability of the central nervous system, weaken the body's thermoregulatory functions and promote heat stroke. When the body temperature rises above 38°C, this effect is even stronger. If we lower the body temperature to 37 ° C, we can see a reduction in the number of mistakes made 1 .
As we can see, thermal comfort is not only convenience, but even compulsion. However, in order to take advantage of the positive features of an air-conditioned truck cabin, we should take care of the proper operation of the air conditioning system. The following tips will help us with this.
1. The basic activity is the initial interview with the vehicle user. Properly asked questions allow you to assess the condition of the air conditioning system and identify the elements that are worth paying attention to in the first place. For example, the questions "When was the system last serviced", "Is it cooling?".
2. Tapping the air conditioning . The password that appears very often during the user's conversation with the service technician. We must remember that the air conditioning system is a system of a certain size, so the amount of refrigerant present in it is specified by the vehicle manufacturer and it is this amount that allows the compressor and other system components to work without problems. Therefore, refrigerant replenishment should be done using the appropriate tool, which is the air conditioning service station, and using the refill database (the database can be downloaded free of charge at https://www.mahle-aftermarket.com/eu/ ). Too much refrigerant can wash off the oil film on the compressor components. Another danger is the increase in pressure in the system, as well as the effect of liquid blockage, which leads to damage to the compressor. In turn, too little refrigerant can lead to insufficient lubrication of the compressor components, because it is the refrigerant that is the carrier medium for the oil.
3. In addition to the refrigerant, the air conditioning system also uses oil. Its task is to lubricate the compressor elements and protect the walls of the system elements against corrosion. How much should we put into the system? The right principle is equality "what we download, we put in" . Too much oil can cause serious effects. Blockage of refrigerant flow in the evaporator, or worse, mechanical damage to the air conditioning compressor.
4. Another chemical substance that we can encounter during the routine maintenance of the air conditioning system is contrast. This substance is designed, together with the lamp emitting UV radiation, to help detect leaks. Remember, already 1g of contrast in the system allows you to use the previously mentioned lamp. Excess contrast changes the physical parameters of the oil, thins it, which negatively affects its lubricating properties.
5. Leaks are a common problem that often occurs in the air conditioning system. Even an efficient system without leaks is at risk of refrigerant loss. The reason for this are micro leaks, but also a phenomenon called diffusion. But what if the leak is excessive? In this case , an air conditioning sealant is often used. It works by reacting with the air surrounding the leak and changing its state from liquid to solid. Remember, however, that improper use of sealant can lead to damage to the compressor. In addition, the current regulations say that in the event of a loss of refrigerant in the system above 40 g (in the case of one evaporator) and 60 g (in the case of two evaporators), the system should be inspected and repaired, and the repair should be documented.
6. One of the processes during system operation is creating (and maintaining for about 20 minutes) a vacuum . This stage allows not only to properly replenish the system with factor, but most importantly, it allows you to remove moisture from the system. The vacuum should be created and maintained for 20-30 minutes. This time allows the water molecules to change state of aggregation, the liquid turns into a gaseous state. In this way, we can remove the moisture present in the system. Often, you can encounter a situation where this time is drastically reduced to 10 minutes or less. This is an obvious mistake and you should avoid this practice. We should also remember that the process of maintaining the vacuum should be carried out at a temperature close to 200C. Lower temperatures (below 120C) will not ensure proper removal of moisture.
7. Use an identifier or a refrigerant analyzer. This equipment allows for a quick assessment of the chemical composition of the contents of the air conditioning system. In vehicles traveling on our roads, we can meet not only systems in which the r1234yf factor has been replaced with r134a, but we can also meet with a mixture of hydrocarbons. An example would be a mixture of gases, propane and butane. The oils that we use in the system have been developed for "classic" refrigerants. Their combination with hydrocarbons can shorten the life of system components, including the compressor. It should also be remembered that hydrocarbons are flammable, and this poses a risk not only of damage to the air conditioning station, but also, most importantly, drastically reduces safety in the event of a traffic accident and poses a threat to the personnel operating the system.
8. Remember to replace the cabin filter and properly disinfect the system. These two activities not only make us breathe cleaner air, with a reduced amount of PM2.5 dust, but also ensure microbiological safety in the vehicle cabin.
1. Study "Moods of bus drivers and their ability to react in high temperatures" acc. Sun Xinolong, Zhao Hui, Feng Shuminb, Li Zhenning.
