When the engine is working, the coolant heated by the engine cylinder at high temperature enters the heat exchanger through the water inlet pipe under the action of the water pump returning to the engine cooling system, and the heat emitted by the coolant is sent to the carriage or windshield by the air blown by the blower, so that the temperature in the carriage is raised.
Extended data:
Matters needing attention in the use of automobile warm air:
Don't turn on the warm air when you get on the bus. The car warm air blows the residual heat of the engine into the car through the blower. When the engine was just started, the engine did not generate enough temperature. In this case, it is not only impossible to turn on the warm air, but also increases the discharge capacity of the battery.