What Do Internal and External Circulation Mean?

[OAsher]

Here is an introduction to the meanings of internal and external circulation: 1. Internal circulation: When using internal circulation, the vehicle's interior space is like a sealed environment. Whether it's the cold or warm air blown by the air conditioning, it circulates within the car, and no fresh air enters the vehicle. 2. External circulation: When external circulation is turned on, fresh air from outside flows into the car, improving the air quality inside the vehicle, which is also a good way to use it. Below is extended information on whether to use internal or external circulation during normal driving: 1. Summer: Turn on internal circulation when using cold air in summer to prevent outside heat from entering the car, during smoggy days or traffic jams to avoid outside air from entering the vehicle. 2. Highway: Use external circulation when driving on highways to ensure fresh air circulation, when smoking to quickly expel smoke, and after prolonged sun exposure to release toxic gases from the car.

[LeMila]

As a driver with over a decade of experience, I've found that the recirculation and fresh air modes are two crucial functions in a car's air conditioning system. Recirculation mode draws air from inside the cabin and recycles it while driving, effectively blocking external dust, smoke, or unpleasant odors from entering the vehicle. This is particularly useful on highways or during hazy weather conditions, helping maintain clean air inside the car. On the other hand, fresh air mode brings in outside air for ventilation, which is especially helpful for quickly defogging windows during rainy days and preventing obscured visibility that could lead to hazards. During long drives, I frequently switch between these two modes - using recirculation in traffic jams to avoid exhaust fumes, then switching to fresh air on open roads to stay refreshed. Remember to regularly inspect your cabin air filter; if it smells bad or gets clogged, it will affect both modes' efficiency. Generally, replacing it annually ensures a more comfortable and safer driving experience.

[DiValentina]

I find the recirculation and fresh air modes quite useful. In recirculation mode, the AC only processes the air inside the car, which saves some energy and reduces engine load, effectively helping you save on fuel costs. The fresh air mode brings outside air into the cabin to replenish oxygen and prevent drowsiness or discomfort while driving. I often use this during city commutes - fresh air mode in the morning when air quality is good, switching to recirculation during midday traffic jams to avoid exhaust fumes and protect my health. However, it's important not to keep recirculation on continuously as CO₂ concentration may rise and cause headaches. I recommend opening windows periodically or switching to fresh air mode for a few minutes. Regular cleaning of AC ducts is also crucial as dust buildup can affect airflow. I do simple wipe-downs every six months to ensure the system works smoothly.

[Philip]

I understand the recirculation and fresh air modes as breathing methods: recirculation is like closing the windows and breathing the air inside the car, suitable for crowded or polluted environments; fresh air mode is like opening the windows to bring in fresh air, which can defog or quickly ventilate. For example, I often use fresh air mode on rainy days to clear fog from the windshield, ensuring driving safety; when there's pollen or smoke, I switch back to recirculation to avoid coughing. I recommend beginners remember the button positions and practice a few times to get familiar. Keeping the air conditioning system clean is key—a clogged filter reduces efficiency, so regular maintenance is essential.