What are the symbols for the internal and external circulation of car air conditioning?

[Reyes]

Usually, it is a side view of a small car shape with an arrow passing from the front windshield into the car, indicating external circulation. If there is a rotating arrow inside the car, it indicates internal circulation. Below is relevant information: 1. Car internal and external circulation refers to the direction of air intake for the air conditioning, either from inside or outside the car. Simply put, internal circulation means the air inside the car is heated or cooled and then recirculated back into the car; external circulation means air from outside the car is heated or cooled and then sent into the car, allowing gas exchange between the inside and outside of the car. 2. External circulation mode uses a fan to draw air from outside the car into the interior, meaning the air passages between the outside and inside of the car are connected. The air blown by the fan comes from outside the car, and even if the fan is not turned on, airflow is still drawn into the car while driving, replenishing the fresh air inside.