What is the difference between the car's internal circulation and external circulation?
4 Answers
The difference between internal circulation and external circulation in a car: Internal circulation refers to the air inside the car being heated or cooled and then recirculated back into the cabin. External circulation refers to drawing air from outside the car, heating or cooling it, and then introducing it into the cabin, effectively exchanging air between the inside and outside of the vehicle. Relevant information about car air conditioning is as follows: Introduction: The car air conditioning device (air-conditioning-device), commonly referred to as car air conditioning. Function: It is used to regulate and control the temperature, humidity, air cleanliness, and airflow within the car cabin to optimal conditions, providing a comfortable environment for passengers and reducing travel fatigue; it also creates favorable working conditions for the driver and plays a crucial role in ensuring safe driving as a ventilation device.
I often think about the difference between recirculation and fresh air modes while driving, as it directly impacts comfort. Recirculation mode closes the external air vents, circulating only the air inside the car without bringing in fresh air. The advantage is that when you turn on the AC, whether heating or cooling, it reaches the set temperature quickly because the system doesn't need to adjust to external air changes. For example, in summer when the car feels like an oven, I use recirculation with the AC button, and cool air quickly lowers the temperature; it works similarly in winter. The downside is prolonged use can make the air stuffy, with CO2 buildup causing drowsiness. Fresh air mode draws outside air into the cabin, providing oxygen. This is great for defogging on humid days—opening fresh air mode when windows fog up brings in dry air that clears mist fast, improving visibility instantly. However, in city traffic, fresh air mode can suck in exhaust fumes, which isn't healthy. So I usually switch to fresh air mode for ventilation every hour or use auto mode for smart switching. Remember, this also reduces AC load, saving energy.
I think the key difference between recirculation and fresh air modes lies in who controls the air source. Recirculation locks in the cabin air, repeatedly filtering and circulating it without letting outside dust or pollution enter. This is most suitable for heavy traffic or poor air quality areas, preventing exhaust inhalation. I use recirculation more often on long drives because the AC works more efficiently – the system doesn't need to work hard to heat or cool new air, saving some fuel or electricity. But its drawback is the lack of fresh air replenishment, which can make the cabin stuffy over time and affect the interior environment. Fresh air mode does the opposite, introducing outside air to regulate oxygen levels and prevent drowsiness. It's most effective for defogging on rainy days because when humid cabin air meets dry fresh air, the fog disappears quickly. However, heating may be slower in winter. I usually balance both: using recirculation more in extreme heat for faster temperature adjustment, while normally keeping fresh air mode on to maintain air circulation – this makes driving more comfortable and safer.
As a health-conscious individual, I see the internal and external air circulation as matters of air quality and in-car environment. The internal circulation only recirculates the air inside the car, which is good for filtering pollen and dust, but it tends to accumulate carbon dioxide, giving me headaches during long drives. The external circulation brings in fresh air, providing ample oxygen for more refreshing breathing, though it may introduce pollutants. On smoggy days, I use internal circulation plus an air filter to protect my health, while on clear days, I switch to external circulation to stay alert. When it comes to defogging, external circulation wins—dry fresh air helps prevent moisture-induced fogging. Remember to switch between them regularly to avoid stale air.
