A stream of air (or another fluid) outgoing from a nozzle tends to follow a nearby curved or flat surface: this fluid-dynamic effect is called Coanda effect. Using the Coanda effect, air distribution is obtained without any direct mechanical obstruction of the ducts, and it is selectable using external control signals. These features are used to improve thermal comfort in a simple and cheap manner. The main idea consists in using air flow from defroster diffuser rather than that one from traditional central outlets in order to realize the ventilation mode. The defroster air flow is deflected toward passenger compartment  thanks to Coanda effect on cockpit skin. When defroster mode is requested a movable blade, powered by traditional electric motor, outgoes from diffuser and detaches air flow from dashboard. In defroster mode the Coanda diffuser works as traditional deiceing/defogging system.

The functionality of central air-flow outlets is replaced by using Coanda air-diffusers coupled with side ventilation outlets; in this manner is possible to get space-saving on dashboard center line in order to place entertainment system or storage boxes.