The car air conditioner blows the wind into the car, and then from where does it get out of the car? How is the air convection cycle formed?
It is estimated that many people will have such questions. We all know that there is an air inlet in the lower right corner of the front windshield of the car, and the air outside the car enters the car from here, and after filtering through the air conditioning filter, it flows through the evaporation box or the warm wind and water box to cool or heat the air, which forms a cold and warm air conditioner. However, the space inside the car is limited, and the air outside continues to enter the car, if it is not discharged, the inside of the car is not going to explode.
In addition, people need to breathe in the car, need to replenish fresh oxygen in time, and discharge the exhaled carbon dioxide and other dirty exhaust gases in time to avoid suffocation. Therefore, the car must have an outlet to discharge the dirty air in the car. But we looked through the whole car and couldn't see the air outlet, so how did this dirty air get out of the car?
Some people say that it is discharged from various door seams, trunk door seams, etc. But this is not possible. If you think about it, when it rains, rain can't get into the car through these gaps, so how can the air drain quickly from these parts? We sat in the car, closed the door, almost isolated from the outside world, the gaps in each door are extremely small, even if a small amount of air can be discharged, it is not enough to meet the requirements of human breathing. So it is impossible for air to be discharged from here.
So where is this outlet?
The location of this outlet is so hidden that we couldn't see it at all outside. You need to remove the rear bumper, or remove the decorative panels and soundproof cotton on both sides of the trunk, and on the body under the sides of the trunk, there is a square hole, which is the air outlet of the car car, also known as the pressure relief hole, the ventilation hole or the ventilation window. Plastic meshes or blinds are installed on top of it to block outside dust, water and other debris from entering the compartment, but air can enter and exit freely from here.
With air inlets and outlets, air can circulate normally in the car. When the car is driving, the front is a positive pressure area, and the fresh air continues to enter from the air inlet; the back is the negative pressure area, and the dirty air in the carriage is "pumped" out from the air outlet, which forms a good air circulation and ensures the freshness of the air in the car. If the blower is turned on, it will speed up the flow of air in the cabin, allowing the air to be replaced more quickly and thoroughly. This process of circulating air in the car is called car ventilation, which is a relatively important design content in car design.
Even if the car is parked in place and the doors and windows are closed, the air can circulate in the car. People breathe in the car, they inhale oxygen, and exhale carbon dioxide. When the air pressure in the car is lower than the external atmospheric pressure, the air outside the car will enter the car from the air inlet; when the person exhales too much carbon dioxide, the temperature and pressure inside the car rise, which is greater than the external atmospheric pressure, the dirty air in the car will be discharged from the outlet, and then the fresh air outside the car will be replenished. In this circular flow, the ventilation in the car is realized. It is often questioned whether sleeping in a car with doors and windows closed will suffocate to death. From this analysis, it is impossible. As for the suffocation death of some children locked in the car in the summer, it is all heat death, not suffocation.
In addition, the ventilation design of this car can also affect the sound of the car closing the door. When we close the door, we will seal a part of the outside air in the car, and the air pressure in the car will increase rapidly in a short period of time, and it is difficult for the door to close smoothly. If the car ventilation is well designed, reasonably control the speed and direction of air flow at the air outlet, you can smoothly discharge the excess air out of the car, the door can be closed smoothly, and the sound of closing the door will be better. The sound of many luxury cars closing the door is extremely pleasant, not necessarily the door sheet metal is done well, and the ventilation system also has a great credit.