What is the use of the air inlet in front of the car? Is it engine cooling or air conditioning ventilation?

I don't know what kind of air net you are talking about. One is medium net, usually radiator, water tank and fan. Engine cooling. Second, the air filter, that small hole, is also in front of the nose, controlled by the throttle, and mixed with oil and gas. Third, the air inlet of the air conditioner is generally under the windshield, and the hot and cold air is controlled by the blower. Basically, these three. A better car may have a turbocharger.