Where does the outside air circulation exit from?
2 Answers
The air inside the vehicle during outside air circulation is primarily expelled through ventilation holes in the vehicle's interior trim and trunk. The interior of the vehicle has several ventilation holes connected to the outside through the interior trim and trunk. The external breathing ports are hidden behind the fenders above the tires or within the side covers of the rear bumper. These ventilation holes (breathing ports) serve two purposes: first, they help release the air pressure from the outside air circulation of the air conditioning system; second, they prevent pressure buildup inside the vehicle when doors are closed quickly, which could otherwise cause discomfort or injury to passengers' eardrums due to pressure waves or even shattered glass. These ventilation holes are equipped with filters to prevent dust or insects from entering and also provide some damping effect to reduce external noise. When the outside air circulation is activated, the air intake located at the firewall is opened by the air conditioning system's computer. The vehicle's blower then draws outside air through a micro-dust filter into the two heat exchangers (for cooling and heating) inside the evaporator. The air, after passing through the heat exchangers, is blown out through the air vents.
I've been driving for over ten years and often use the fresh air mode to ventilate the cabin. When outside air comes in, the stale air inside exits through vents located at the bottom and rear of the car body. These vents are designed to balance pressure and prevent stuffiness. In fact, there are hidden ventilation holes near the floor pan or rear bumper where air naturally flows out—much less noticeable than the intake vents below the windshield. At highway speeds, wind noise also indicates airflow movement. Remember, if you don’t use the fresh air mode for extended periods, cabin air can become stale and cause dizziness. It’s best to check these vents for blockages during every car wash to ensure the system works smoothly, as this directly impacts cabin comfort.
