What do the internal and external air circulation modes in a car mean?
2 Answers
Internal and external air circulation modes in a car represent: 1. Internal circulation means the air inside the car is heated or cooled and then recirculated back into the car; 2. External circulation means the air outside the car is heated or cooled and then brought into the car, allowing gas exchange between the inside and outside of the car. The internal circulation mode closes the airflow passage between the inside and outside of the car, forming an internal airflow circulation, which can effectively and promptly prevent external dust and harmful gases from entering the car and maintain the internal temperature. The external circulation mode uses a fan to draw outside air into the car, and even if the fan is not turned on, airflow will still be drawn into the car while driving, replenishing the car with fresh air.
As a seasoned long-distance driver, I believe the recirculation and fresh air modes are simply two ventilation settings in the car's AC system, with straightforward differences. Recirculation mode means the existing cabin air gets repeatedly drawn into the AC system to be heated or cooled before being blown back inside, without bringing in outside air. This allows faster cooling in summer and quicker heating in winter, making it fuel-efficient and comfortable on highways. The fresh air mode works oppositely by drawing in outside air, processing it, then circulating it inside - ideal when ventilation is needed, like during prolonged window-closed driving or foggy conditions. For instance, I use recirculation in tunnels or dusty areas to block odors, but switch to fresh air in clean environments to replenish oxygen and prevent drowsiness. Remember not to overuse recirculation as stale air may cause oxygen deprivation; I periodically switch to fresh air for ventilation, ensuring safer and healthier driving. The key lies in judicious toggling between modes!
