Why does the solenoid valve work normally but the motor does not rotate when the air conditioner is cooling and heating normally?
The refrigeration principle of automobile air conditioners is the same as that of other refrigeration devices. The refrigerant working fluid absorbs heat in the evaporator for cooling in the liquid state. The low-temperature liquid absorbs the latent heat of vaporization and becomes refrigerant gas, which is sucked and compressed by the compressor. The pressure and temperature of the compressed gas increase, and then flow into the condenser, and the condenser Air-cooled car air conditioners all use air-cooled snow to condense the refrigerant gas. The condensed high-temperature and high-pressure liquid is stored at the bottom of the condenser and the liquid reservoir. The heat released during condensation is taken out by the fan and dispersed outside the vehicle. , when the high-temperature and high-pressure liquid flows through the expansion valve, it enters the evaporator in a low-temperature and low-pressure liquid state to absorb the latent heat of vaporization and cool it, thus completing the refrigeration cycle.
Car air conditioners are the same as other air conditioners and refrigeration. Lowering the temperature through artificial means (or transferring the temperature from a higher object to a lower object) is called "artificial refrigeration", or "refrigeration" for short.
The vapor compression cycle refrigeration (air conditioning) system is completed through four processes. That is: throttling process - evaporation process - compression process - condensation process.
Throttle, through the throttling device, that is, the throttle valve (also called a regulating valve or expansion valve, usually called an expansion valve or orifice in automobile air conditioners). The high-pressure liquid of the refrigerant passes through the narrow passage of the valve, causing its flow and pressure to be throttled and reduced, and becomes a low-pressure liquid entering the evaporator. At this time, although the flow and pressure of the refrigerant have changed, the liquid form of the refrigerant has not changed.
Evaporation, through the heat exchange device, that is, the evaporator. The low-pressure liquid exchanges heat with the heat in the outside (cab) (i.e., transfers heat, actually absorbs heat) to produce boiling (vaporization). As a result, the temperature of the space is continuously reduced. Low-pressure refrigerant vapor is produced after boiling (vaporization), thereby changing the form of the refrigerant from a low-pressure liquid to a low-pressure gas, but the pressure does not change.
Compression, through a gas compression device, that is, a refrigeration compressor. Low-pressure and low-temperature refrigerant gas is sucked into the compressor, compressed, and turned into high-pressure and high-temperature gas and discharged. During this period only the pressure changes, but the shape of the gas remains unchanged.
Condensation, through the heat exchange device, that is, the condenser (also called the radiator). The high-pressure and high-temperature refrigerant gas transfers heat to the outside world (actually releases heat) and condenses (cools) into a high-pressure liquid, thereby changing the form of the refrigerant from high-pressure vapor to high-pressure liquid, but the pressure does not change.
The entire refrigeration process is completed by forming a circulation system through these four devices. The system is connected by pipes. The refrigerant circulates repeatedly in this system, thereby continuously reducing the temperature.
In order to ensure normal refrigeration, a liquid storage dryer (usually called a drying filter or drying bottle) is added to the system between the condenser and the expansion valve. Dry and filter the moisture and impurities in the refrigerant, and store the refrigerant required for the refrigeration cycle.
In addition, there are some ancillary devices, such as electronic cooling fans for condensers and blowers for evaporators, which are all essential. Some also add a gas-liquid (oil) separator between the low-pressure side evaporator and the compressor. In order to enable the air conditioning system to operate safely and automatically, the system is equipped with pressure controllers (pressure switches) on the high and low pressure sides respectively; a temperature controller (temperature sensor or sensor) is installed on the evaporator on the low pressure side; the entire electrical system is controlled by a computer or Controlled by a controller to achieve automated operation.
In fact, there is what you commonly call an external unit, but it is hidden and arranged. Different types of air conditioning systems are arranged differently. At present, integrated heating and cooling air conditioning systems are widely used in cars. Its layout is to assemble the evaporator, warm air radiator, centrifugal blower, control mechanism, etc. together, which is called the air conditioner assembly.