What is the usage method of the car air conditioning's internal and external circulation modes?
3 Answers
Car air conditioning's internal and external circulation modes can be switched by pressing the circulation mode button on the control panel. Use internal circulation mode when driving in congested urban roads, and switch to external circulation mode for long-distance or highway driving. Car air conditioning refers to the air conditioning device installed in vehicles, which can cool, heat, ventilate and purify the air inside the cabin, providing a comfortable environment for passengers, reducing driver fatigue and improving driving safety. The car air conditioning system mainly consists of compressor, electronically controlled clutch, condenser, evaporator, expansion valve, receiver-drier, pipelines, condenser fan, vacuum solenoid valve, idle speed controller and control system.
The car's air conditioning system has distinct uses for its internal and external circulation modes. Internal circulation is ideal for rapid cooling or heating—I simply press the button on the dashboard (usually an icon with an arrow circulating inside the car) to switch. Especially after the car has been baking in the summer sun, I activate internal circulation first for 5-10 minutes to let the cold air recirculate inside without drawing in hot air, allowing the AC to cool faster. In winter, if the windows fog up, turning on internal circulation before increasing the heater setting works better. In heavily polluted areas like traffic jams or tunnels, I keep internal circulation on to avoid inhaling exhaust fumes. External circulation draws in fresh air from outside, which I often use during highway driving to improve ventilation and ensure sufficient oxygen supply; or for dehumidifying after rainy days to prevent window fogging. Remember not to use internal circulation exclusively for long periods to avoid stuffy air or health impacts—it's better to switch to external circulation every half hour on average for air exchange. Regularly cleaning the AC filter is also crucial.
I prioritize energy efficiency and fuel economy, and mastering the use of the car's air conditioning recirculation mode can help you save money. When using the recirculation mode, the AC system doesn't have to process hot outside air, reducing engine load and improving fuel efficiency. I often use recirculation mode to quickly cool down the cabin before long summer drives to minimize fuel consumption. However, don't overuse it - I switch to fresh air mode every 20 minutes when using recirculation to prevent CO2 buildup. Fresh air mode is ideal during spring and autumn when opening windows isn't practical, like on low-pollution rural roads where it brings in fresh air for better comfort. Combining this with automatic climate control works best - pressing the AUTO button intelligently balances both modes. Regular maintenance extends your AC's lifespan and prevents malfunctions.
