The purpose of air conditioning in passenger cars is to ensure the optimum temperature, humidity, dust level, and amount of oxygen in the air.
Optimum sanitation
According to standards, in a passenger car it is necessary to maintain the following air values:
- temperature 22 degrees Celsius;
- relative humidity 40 - 60%;
- air flow per passenger in the warm season 25 cubic meters per hour, in the cold season 20 cubic meters per hour;
- the content of dust particles is not more than 1 gram per cubic meter of air;
- carbon dioxide content of 0.1%.
All parameters should be controlled automatically. On Russian Railways, air conditioning in wagons is carried out year-round, but the systems do not affect air humidity. Therefore, such air conditioning in passenger cars is considered incomplete.
Air conditioning equipment
Air conditioners for cars are specially designed to work in the heat and under the bright scorching rays of the sun. The single-channel equipment with recirculation, of a paracompression type, works on HFC-12 as a refrigerant.
Compressors in air conditioners for cars can be glandless or stuffing box. The first type is installed with a built-in AC motor. The second is suitable for DC compressors.
Electricity is supplied to the air conditioning installation of passenger cars centrally or autonomously from a generator located in the car. The generator starts when the wheels move.
The scheme of the air conditioner in a passenger car
The fan draws in air from the premises, mixes it with the outside in a ratio of 1: 3, passes it through a filtration system. After which the air is cooled passing through the evaporator. The evaporator of the air conditioning system for passenger cars is a coil of a ribbed tube that evaporates refrigerant. After the evaporator, air is supplied to the car through the supply air openings.
In the cold season, air heating is carried out by a heater located in the duct.
Air conditioning in cars of foreign production is carried out using single-channel units with bypassing and recirculation. In such a device there is a bypass duct with a valve controlled by automation. The valve prevents recirculation air from reaching the fan directly, bypassing the cooling or heating system.
