Which button is the one-touch defogging function in Audi?

[EdwardAnn]

FRONT button is for front windshield defogging. In winter, due to the large temperature difference between the inside and outside of the car, fog is prone to form on the windshield, obstructing the view. If you manually wipe off the fog while driving, it can easily distract you and affect driving safety. Turning on this function can conveniently and quickly remove the fog. The principle of the car defogging button: Physical principle of cold air: After the liquid refrigerant absorbs the heat of the cooled object in the evaporator, it vaporizes into low-temperature and low-pressure steam, which is sucked in by the compressor and compressed into high-temperature and high-pressure steam, then discharged into the condenser. In the condenser, it releases heat to the cooling medium (water or air) and condenses into high-pressure liquid, which is then throttled by the throttle valve into low-temperature and low-pressure refrigerant, and then enters the evaporation device again to absorb heat and vaporize, achieving the purpose of cyclic refrigeration. In this way, the refrigerant completes the refrigeration cycle in the system through four basic processes: compression, condensation, throttling, and evaporation. Physical principle of hot air defogging: When gas containing fog flows through the defogger at a certain speed, due to the inertia of the gas, the liquid droplets accumulated due to the collision of fog with the wave plate are large, and the gravity generated by the droplets exceeds the combined force of gas lift and liquid surface tension, causing the droplets to separate from the surface of the wave plate. Methods to prevent window fogging: Preventive methods such as spraying anti-fog agents: Spray a little defogging agent on the window and then wipe it clean to remove dirt and spots on the glass. When polishing the glass, a thin transparent protective film is formed on the glass, which can effectively prevent water vapor from condensing on the glass and forming a fog layer, especially suitable for cold winters. Air conditioning refrigeration method: Use the air conditioning dehumidification function to reduce air humidity and remove fog. Turn on the air conditioning to blow cold air forward, use the air conditioning dehumidification function, and you can remove the fog vapor on the front windshield. However, if the humidity is too high, the effect of the air conditioning is not obvious, and you can slightly open a small window to quickly reduce the humidity in the cab. Air conditioning heating method: Use the method of reducing the temperature difference to eliminate fog. In winter, use warm air to blow hot air onto the glass to quickly increase the temperature of the front glass and reduce the difference between the inside and outside surfaces of the window, which can prevent the fog vapor on the front windshield in time. However, the back and side temperatures of the glass rise slowly, so it takes a long time to eliminate all the fog.