Under what circumstances are internal circulation and external circulation used?

Under normal circumstances, cars use external circulation mode in ventilated weather and internal circulation mode in high temperature and haze weather.

In the internal circulation mode, the air in the car does not introduce fresh air from the outside, but circulates through the air conditioning system. In this mode, the air in the car can be used for cooling or heating, which can reach the required temperature faster. However, it should be noted that long-term use of internal circulation may lead to stale air, lack of oxygen and even odor in the car.

In the external circulation mode, the air in the car will automatically introduce fresh air from the outside, enter the refrigeration/heating system for treatment and be released. This mode can keep the air in the car fresh and is suitable for use when there is odor or smoke in the car. However, it should be noted that when using external circulation, if the environment outside the car is polluted or the temperature difference is too large, the temperature control effect inside the car may be affected.

Therefore, in actual driving, it is necessary to choose the internal circulation or external circulation mode according to the actual situation. In ventilated weather, external circulation can be used; In the case of high temperature, strong wind and smog, the internal circulation mode is more suitable.

Precautions:

1. Choose the mode according to the actual situation: under the condition of suitable temperature and fresh air, you can choose the external circulation mode to keep the air circulation in the car. In high temperature, strong wind, smog and other environments, the internal circulation mode should be selected to prevent outdoor pollutants from entering the car.

2. Replace the air conditioner filter regularly: Long-term use of the internal circulation mode will make the air inside the car stale. In order to avoid the smell in the car and the deterioration of air quality, the air conditioning filter should be replaced frequently.

3. Pay attention to timely window ventilation: if the internal circulation mode is used for too long, the air inside the car will become sultry and oxygen-deficient, which is not conducive to health. Therefore, it is also necessary to properly open the window for ventilation.

4. Avoid using the internal circulation mode in traffic jams or closed garages: In these cases, the oxygen content circulating in the air conditioning system is not enough to meet the needs of the human body. If you continue to use the internal circulation mode, it may lead to physical discomfort and even affect safe driving.