The invention relates in general to an air-conditioning device for motor vehicles.
It relates more specifically to a device for air-conditioning a cabin of a motor vehicle, comprising an air-conditioning unit installed in front of the dashboard, able to be supplied with external air and/or with recycled air taken from the cabin and passing through a recycling pipe arranged in said dashboard, and able to deliver to the rear region and the cabin a flow of conditioned air through a delivery pipe connecting said unit to a vent.
Certain air-conditioning devices actually comprise a supply shutter which, in a particular position known as the recycling position, allows the vehicle cabin to be supplied in an closed or an almost closed circuit. This mode of operation is particularly used when the vehicle passes through polluted areas. This mode of operation is also useful in cold weather, when starting the vehicle, so as to allow the vehicle to warm up more quickly, and also when the external air is very hot, to allow energy savings. In almost all vehicles equipped with recycling means, the recycled air intake is arranged in the dashboard.
EP 0 645 267 describes an air-conditioning device for motor vehicles in which the recycled air intake is in the rear region of the cabin and the recycling pipe is arranged in part in the floor of the cabin. However, this device described in this document has no pipe for delivering conditioned air to the rear region of the cabin.
In vehicles which have an air vent in the rear region of the cabin, the corresponding air delivery pipe is generally arranged in the floor of the cabin and the air delivered flows from the conditioning unit to the vent.
The purpose of the invention is to propose a conditioning device such as mentioned in the introduction which makes it possible, on demand, to take recycled air from the rear region of the cabin.
According to the invention, the device is one wherein there is provided, in the dashboard, a branch pipe connecting said recycling pipe to said delivery pipe, said branch pipe dividing the delivery pipe into an upstream portion situated between the unit and the junction with the branch pipe, and into a downstream portion situated between said junction and the vent and, in said junction, a rear recycling shutter able to adopt at least two positions, a first position in which it closes off the entrance to the branch pipe, and a second position in which it closes off the exit from the upstream portion of the delivery pipe so as to allow air to be taken from the rear region of the cabin for recycling.
Thus, conditioned air from the unit flows into the downstream portion of the delivery pipe when the rear recycling shutter is in the first position, and air taken from the rear region of the cabin flows in the opposite direction in this downstream portion when the rear recycling shutter is in the second position.
Advantageously, the rear recycling shutter can adopt a third position in which it places the upstream portion in communication with the branch pipe.
This arrangement makes it possible, under extreme conditions, to inject colder or hotter air back into the recycling pipe in order to more quickly reduce or increase the temperature of the air leaving the vents provided in the dashboard.