What is the difference between internal and external air circulation in a vehicle?
2 Answers
The difference between internal and external air circulation in a vehicle lies in the air intake vents. Different locations of the air intake vents result in different airflow movements. Below is a related introduction to external and internal air circulation: 1. Internal air circulation: The air intake vent is inside the vehicle, meaning outside air cannot enter, and inside air cannot exit. Prolonged use of internal air circulation can lead to stale air, decreased oxygen levels, and symptoms such as heat discomfort, fatigue, and anxiety, which can affect driving safety. 2. External air circulation: The air intake vent is located below the front windshield wiper, at the junction between the front windshield and the engine hood. Simply put, it draws outside air into the vehicle. External air circulation ensures proper airflow inside the vehicle and is suitable for use when the outside air quality is good.
Let me tell you, the air recirculation function is super useful in daily driving! When stuck in traffic or passing by a garbage dump, quickly switch to recirculation mode to keep outside odors and dust from entering the cabin. It helps the AC cool faster in summer and improves heating efficiency in winter. But don't keep recirculation on constantly - prolonged use increases CO₂ concentration inside, which may cause drowsiness, especially during long trips. I usually switch to fresh air mode in tunnels for ventilation, and it helps quickly defog windows on rainy days. The smartest approach is alternating between modes: use fresh air when outdoor air quality is good, then immediately switch to recirculation when encountering truck exhaust or smog. Remember to switch to fresh air for 5 minutes after every 40 minutes of recirculation - this keeps driving comfortable and safe.
