Air Distribution System

Air distribution system

General




The air distribution system distributes the air to the passenger compartment. It is used jointly by the heating system and the cooling system in the climate control system. The blower fan draws
air into the system.
Fresh air is taken from through the gap between the hood and the windshield.
The air passes through the filter and the evaporator, past the temperature damper and possibly though the heat exchanger, before being released into the passenger compartment through the vents.
After circulating, the air disappears out of the passenger compartment though air vents at the rear of the vehicle.

The dampers
The task of the dampers is to control the amount of air that goes to each air duct and on out into the passenger compartment.
The temperature damper controls how much air goes through or outside of the heat exchanger. The split temperature damper on vehicles with electronic climate control (ECC) means that it is
possible to set different temperatures on the driver's side and passenger side.

Recirculation
The recirculation damper regulates the amount of incoming fresh air. The recirculation function makes it possible to prevent outside air from entering the passenger compartment, for example
when the ambient air is contaminated with exhaust fumes, smoke, etc. This function can also be used for rapid heating or cooling of the passenger compartment.
If the recirculation function is used for an extended period, the air humidity in the passenger compartment increases. This is due to the moist air exhaled by the passengers. This can result in
mist on the windows.
In the max. cooling control position, approximately 85% of the incoming air is taken from the passenger compartment and approximately 15% from outside. This produces more rapid cooling of the
passenger compartment air.
In vehicles with an air quality system (AQS), the transition to recirculation takes place automatically if the level of contaminants in the outside air increases.

Dashboard vents




The vents are adjustable so that the air can be throttled, blocked or steered in the desired direction.
If the side vents are aimed at the side windows, they help to remove mist from the windows.

Defroster vents
Mist forms easily on the windows in cold, damp weather. The defroster vents release air towards the front windows. The air flow removes the mist that forms. As the air is dry, the airflow also
prevents moist air from the passenger compartment reaching the glass, so countering misting. The air conditioning contributes significantly to these functions by dehumidifying the air at temperatures
above 0 °C.

Floor vents
The four floor vents release heated or cooled air at the feet of the driver and passenger.

Evacuation valves
The evacuation valves are used to even out the pressure in the passenger compartment.
The rubber dampers in the evacuation valves open when the air pressure is slightly higher in the passenger compartment than outside. When the air pressure is the same on the inside and the
outside, the rubber dampers close. This prevents water from penetrating the passenger compartment.