What does the internal circulation A mean?

[StAngela]

Internal circulation A stands for automatic. Here is more related information: 1. Car circulation: (1) Internal circulation: The air conditioning system adjusts the air quality inside the car, allowing the internal air to circulate within the vehicle. (2) External circulation: The air conditioning system adjusts the air quality outside the car, continuously bringing fresh air into the vehicle to replace the internal air. 2. Difference between internal and external circulation: The difference between internal and external circulation is simply the closing of the air intake channel. To put it simply, it's like blowing an electric fan in a closed room. Since the airflow circulates in a closed environment, the exhaled air will be inhaled again, making it an unhealthy ventilation method.

[DiAxel]

I've been using this recirculation mode for over a decade in my car, so I know it best! It makes the AC circulate only the air inside the car, completely isolating it from the outside. It's especially useful on rainy days or when passing through dusty construction sites—it instantly prevents window fogging and keeps dust out. When encountering truck exhaust on highways or bad odors in tunnels, just hit the recirculation button—it's much faster than closing the windows. But be careful: using it too long can make the air stuffy, especially when cooling the car in summer. It's best to use recirculation for the first ten minutes to cool down quickly, then switch to fresh air mode for ventilation once it's comfortable—this helps avoid drowsiness. Never use recirculation for entire long tunnels—oxygen deprivation can be dangerous!

[MacHope]

From a technical perspective, the recirculation mode closes the air intake flap of the air conditioning system, preventing external air from entering the cabin. When sensors detect excessive pollutant levels outside, some premium models automatically switch to this mode. Activating it can improve cooling/heating efficiency by approximately 30%, similar to closing windows when heating a room. However, continuous use exceeding two hours may elevate in-vehicle CO2 concentration above 2,500ppm (compared to 400ppm outdoors), potentially causing driver fatigue. Therefore, many vehicles feature automatic switching functions, with manufacturers generally recommending single-use durations under 40 minutes - particularly important during driving.

[McAbel]

Ladies, remember this! The recirculation mode is like letting your car breathe its own air. If you've just bought some deodorizing bamboo charcoal for your car, turning on recirculation will make the fragrance last longer as it circulates inside. When your car turns into a sauna after being baked by the summer sun, press that button with the arrow inside the car to activate recirculation—it cools down super fast. But keeping it on the whole way when driving your kids to school can make the car stuffy and increase their chances of getting carsick. Here's a big secret—using recirculation with the heater in winter saves fuel! However, never leave the AC on recirculation for too long while parked and waiting, especially if you're taking a nap—there have been accidents reported in the news. And remember, if the windshield fogs up, turn it off immediately!