Summer is coming soon, and turning on the air conditioning as soon as you get in the car will become the norm. If the air conditioning fails and cannot be used, the hot temperature will seriously affect the driver's driving safety.
Summer is coming soon, and turning on the air conditioning as soon as you get in the car will become the norm. If the air conditioning fails and cannot be used, the hot temperature will seriously affect the driver's driving safety.
If one can understand the structure and principles of the air conditioning system, it will help to quickly determine the cause of air conditioning failures, accelerate the progress of troubleshooting, and also avoid air conditioning maintenance personnel charging arbitrarily.
The commercial vehicle air conditioning system is actually a relatively independent system, and it is not closely related to other car systems. Therefore, even if a fault occurs, troubleshooting the cause will be relatively simple. For card enthusiasts with strong hands-on and learning abilities, it is recommended to collect and save it.
Air conditioning structure
Commercial vehicle air conditioning mainly consists of three components: compressor, condenser, evaporator, and a series of auxiliary components including expansion valve, liquid storage dryer, pipeline, condensing fan, blower, and temperature sensing bulb.
Main component functions
The compressor is driven by the engine through a belt, and its function is to suck in low-temperature and low-pressure refrigerant vapor, compress it to the required pressure, and send it to the condenser, which is the power source of the entire air conditioning refrigerant cycle. The higher the engine speed, the faster the refrigerant circulation and the greater the cooling power.
The function of a condenser is to transfer the heat of high-temperature and high-pressure gaseous refrigerant to the outside air, causing the refrigerant to condense into liquid.
The condensation effect of the condenser on the refrigerant directly determines the refrigeration efficiency of the air conditioner. There are usually three ways to improve the condensation effect: 1. Increase the flow rate of air through the condenser; 2. Reduce the temperature of the air passing through the condenser; 3. Keep the surface of the condenser clean and free from contamination.
The evaporator is usually installed inside the cab, and its function is to absorb heat from the cab, causing the liquid refrigerant to absorb heat and vaporize into gas.
The main function of a liquid storage dryer in an air conditioning system is to filter, dry, dehumidify, and store excess refrigerant.
Expansion valves and temperature sensors are generally installed on evaporators, with the temperature sensor typically located at the outlet of the evaporator to detect the outlet temperature of the evaporator, automatically adjust the opening of the expansion valve, control the flow rate of the refrigerant, and maintain stable temperature inside the cab.
Working principle of refrigeration
When the compressor is running, the low-temperature and low-pressure refrigerant vapor generated in the evaporator is sucked in and compressed, and then discharged into the condenser under high temperature and pressure. It is cooled by the condenser fan, and the cooled liquid refrigerant flows into the storage dryer from the bottom of the condenser.
After removing moisture and impurities, the pure refrigerant is throttled and cooled down through an expansion valve. The low-temperature and low-pressure liquid refrigerant flows into the evaporator to absorb heat and cool, and is blown into the cab by a blower to lower the temperature inside the cab. The gaseous refrigerant passes through the evaporator and is then sucked back in by the compressor. This cycle transfers the heat inside the cab to the outside.
The core principle of air conditioning refrigeration is that the refrigerant liquefies and releases heat in the condenser, and vaporizes and absorbs heat in the evaporator.
The above is the structure and cooling principle of important components in a simple air conditioning system. Only by understanding the structure and principle of the air conditioning system can cardholders better determine the cause of air conditioning failures