1. The working principle of internal and external circulation
The inner and outer circulation are controlled by a switch. The current car supports three mode settings: automatic, inner circulation, and outer circulation. The automatic mode is mainly inner circulation. The outer circulation is controlled by the air conditioning sensor in a timely manner to ensure that the air quality in the car is not reduced. There is a decline in air quality (decreased oxygen content, increased pollution), etc.
Internal and external circulation, as the name implies, is that the car air conditioning system uses the air in the cabin to cool and circulate. At this time, the air blower inlet is closed, and the exhaust vent at the rear of the cabin is also closed. Due to the isolation from the outside, the oxygen content in the air will follow the inside of the cabin. The breathing of the personnel gradually decreases, so the inner circulation of the car cannot be turned on for a long time. If the manual mode is selected, the outer circulation needs to be turned on regularly to update the air quality in the cabin.
The outer circulation means that the car air conditioner cools the outside air into the cabin through the blower, and then discharges it through the exhaust port at the rear of the cabin. Obviously, the outer circulation has to cool the outside air with maximum power, which will consume a lot of engine power. In addition, although the car air conditioner is equipped with a filter element, such as car exhaust outside the cabin, toxic gases, etc. cannot be filtered by the air conditioning filter element, so in these cases, it is necessary to activate the internal circulation to ensure the air quality in the cabin.
It can be seen that whether it is external circulation or internal circulation, the air quality in the cabin can be improved at an appropriate time. The two are complementary and indispensable.
2. Tips for using internal and external circulation
(1) The car air conditioner should be cleaned/replaced regularly. If possible, the air duct can be cleaned by the way. In addition, for the current serious PM2.5 pollution, users can also use PM2.5 high efficiency air filters to improve the car environment .
(2) Check whether the air inlet is blocked in time. Fallen leaves, shopping bags, etc. usually fall everywhere. If they happen to fall on the outside air inlet of the air conditioner, they may be sucked into the air inlet of the air conditioner. If it is not cleaned for a long time, the fallen leaves will rot and deteriorate, which will contaminate the air conditioner filter and produce peculiar smell.
(3) The car air conditioner needs a certain temperature condition to turn on. The refrigeration system must ensure that the outside temperature is not lower than 10℃, otherwise the air conditioning system will not work. Of course, when the outside temperature is lower than 10℃, the cabin does not need to use air-conditioning for cooling. .
(4) Do not set the air conditioner to internal circulation all the time. Although internal circulation helps to save fuel, the air in the cabin will become turbid or even lack of oxygen over time.
(5) Do not smoke in the car when it is circulating inside or outside. If you must smoke, you need to open a certain amount of air attack on the glass by the window to let disgust spread away.
(6) Try not to stop and turn on the air conditioner to take a rest. When parking, the gasoline in the cylinder may not be completely burned, resulting in high concentration of carbon monoxide, which may cause poisoning or even death. When the car is driving, the air passes through the air-conditioning equipment to produce convection, and the concentration of carbon monoxide in all air-conditioned cars is very low.