33.2.
Air Distribution System
The air distribution system is basically a mechanical system, and consists of blower fans to remove air, ducts to carry air, and valves to control the air flow. The fans are driven by electric motors and air valves are adjusted by the vacuum adjusters or by mechanical means. Air distribution system differs among automobile manufactures, models and types of air conditioner. However, they fall into three basic types of air-conditioning systems.
In the simplest type, the air conditioner is self contained and its air distribution system is completely separated from the automobile heater system. In this case, air flow is controlled by the fan speed and louvers control the air flow direction.
In the second type, factory-installed air conditioners are manufactured to combine the air distribution system with the heater air distribution system. This arrangement is shown schematically in Fig. 33.1. A combination of cooling, which removes moisture and dirt, followed by desired reheating, provides ideal air-conditioning. Reheating takes place, if air is cooled more in the evaporator, by directing some or all of the cool air across the heater core.
The third type of the air conditioning system is quite complex and is factory installed having fully automatic air distribution system. Once desired temperature is set by the driver, the controls maintain the temperature within maximum cooling to maximum heating limits with proper balance between cooling, heating and blower speed.
