Air Intake

IHKA E38 AIR INTAKE

As on E32 and E31 vehicles, the IHKA Systems can take in fresh air, recirculate air already in the interior, or do both at the same time (recirc. flaps fully open/fresh air flaps 30% open).

Fresh air enters the IHKA E38 system through inlet grilles at the trailing edge of the hood. It flows downward and forward into a plenum which houses the activated-charcoal micro- filter. After flowing through the filter, the air flows rearward and downward into the housing through air intake ducts.







To prevent objects from falling into the fresh air intake ducts while the hood is open, a spring-loaded flap is placed at the entrance to each duct. As the hood is opened, the flaps close automatically When the hood is closed, pushrods mounted to the underside of the hood force the flaps open.

Any water which enters the air intake ducts will flow to an area just ahead of the fresh air flaps. Rubber tubing then directs the water to the evaporator area of the housing, where it drains with any evaporator condensate.


NOTE: System operation should not be checked or evaluated while the hood is open.







As on previous IHKA systems, the fresh air flaps close with increasing vehicle speed to counteract the ram air effect. On E38 vehicles, however, blower speed also influences the amount the flaps close. At low blower speeds, the fresh air flap throttling effect is most pronounced (fresh air flap only 30% open at very high speeds). At higher blower speeds, however, the throttling effect is less significant.







Vehicle Speed Influence on Fresh Air Flap Position