Multifunctional HVAC (heating, ventilation and air conditioning) system of vehicle

The invention provides an air circulating system of a vehicle. The air circulating system comprises a controller, an internal condition sensor, an instrument panel and an extensible ventilator assembly. The internal condition sensor is connected with the controller, and the extensible ventilator assembly is connected to the controller and is pivotally connected to the instrument panel. The ventilator assembly comprises a first ventilator and a second ventilator and can move between a closed position and an open position, and the first ventilator is sunken into the instrument panel and is shielded when the ventilator assembly is located at the closed position, and is extended when the ventilator assembly is located at the open position. The second ventilator is kept from being shielded no matter whether the ventilator assembly is located at the closed position or the open position. The air circulating system has the advantages that cooling conditions can be directionally controlled by the extensible ventilator; the extensible ventilator can descend into the instrument panel once required conditions are met, wide openings can be provided for other ventilators, accordingly, top air can be guided at a low speed, and air can be prevented from being directly blown to passengers while a compartment keeps nice and cool.