It is known to provide a device comprising a cold-air duct, a hot-air duct housing a heating radiator, a mixing chamber communicating with respective air outlets of said ducts, and mixing means suitable for controlling said air outlets in chosen proportions so as to set the temperature of the air in the mixing chamber.
Devices of this type make it possible to mix a flow of cold air originating from the cold-air duct and a flow of hot air originating from the hot-air duct in controlled proportions in order to obtain an airflow at an adjusted temperature in the mixing chamber.
This airflow is then distributed into the passenger compartment of the vehicle by appropriate distribution means, comprising ducts terminating in various vents arranged at chosen locations in the passenger compartment.
The mixing means generally comprise a mixing flap, of the butterfly type, mounted pivotably about a spindle situated close to the heating radiator and including two wings suitable for controlling the outlets of the cold-air and hot-air ducts respectively.
Such a flap can be deflected from one to the other of two extreme positions comprising a "hot" position (in which the outlet of the cold-air duct is closed and the outlet of the hot-air duct is open) and a "cold" position (in which the outlet of the hot-air duct is closed and the outlet of the cold-air duct is open).
Such a device, with a mixing flap of the butterfly type, has the particular drawback that, when the flap passes from the "hot" position to the "cold" position, cold air enters the mixing chamber from a region of the outlet of the cold-air duct which is located close to a free edge of the butterfly flap. This particular region lies exactly on the opposite side to the region of the outlet of the hot-air duct through which the hot airflow enters the mixing chamber, that is to say close to an opposite edge of the butterfly flap. It results therefrom that the cold airflow and the hot airflow have a tendency to be layered, so that mixing of them can occur only a long way from the heating radiator, which requires an increase in the volume of the mixing chamber and hence of the device.
The object of the invention is essentially to surmount such a drawback.
Hence the invention envisages promoting the meeting and the effective mixing of the cold airflow and of the hot airflow in a region closer to the heating radiator, so as to leave space, downstream of the heating radiator, for the distribution of the air.