Ventilation – Vehicle – Having inlet airway
Reexamination Certificate
2002-08-09
2003-08-19
Boles, Derek (Department: 3744)
Ventilation
Vehicle
Having inlet airway
C454S069000, C454S159000
Reexamination Certificate
active
06607433
ABSTRACT:
The invention relates to devices for heating and/or air-conditioning the cabin of a motor vehicle.
More specifically, it relates to a mixing device for distributing, in variable proportions, a main air stream, particularly a stream of air flowing through an apparatus for heating and/or air-conditioning the cabin of a motor vehicle, between at least one hot air duct and at least one cold air duct.
It also relates to an apparatus for heating and/or air-conditioning particularly the cabin of a motor vehicle, comprising a casing delimiting a passage through which an air stream flows, this passage splitting into at least one hot air duct and at least one cold air duct.
Apparatuses for heating the cabin of a motor vehicle generally comprise a casing housing a blower for blowing an air stream through the casing and then distributing it into the cabin. A heater matrix, mounted as a bypass in a heating-air duct, allows the air to be heated before it is introduced into the cabin when the outside temperature is low, for example in the winter.
In order to allow the user to set the air temperature to suit him, the ventilation and heating apparatus is equipped with a device for mixing the air which allows the air stream to be distributed in variable proportions between the hot air duct and the cold air duct. The mixing device also allows the ventilation and heating apparatus to be operated in a “hot” mode in which the cold air duct is entirely shut off so that all of the air passes through the heater matrix, and in a “cold” mode in which the hot air duct is entirely shut off so that all of the air avoids the heater matrix. The mixing devices, in order to operate satisfactorily, need to meet a certain number of requirements.
First of all, the device needs to guarantee perfect sealing of the hot air and cold air ducts. In the cold mode, this involves avoiding drawing in hot air which would have the effect of heating up the air introduced into the cabin of the vehicle. In the hot mode, it involves avoiding drawing in any cold air so as to make best use of the heating capability of the matrix.
The device has to allow flexibility in the aerothermal optimization of the heating apparatus. What happens is that this apparatus has several outlets, particularly a deicing outlet, an outlet level with the dashboard and an outlet level with the feet of the driver and of the front-seat passenger. In better-equipped vehicles, it also comprises an outlet for the rear seats. The mixing device needs to be able to duct and to direct the air stream toward preferred points so as to distribute it correctly among the various outlets. It has also to allow the relative amount of hot air and of cold air to be adjusted precisely and to allow the hot and cold air streams to be mixed correctly.
Furthermore, the apparatus has to be as compact as possible in order to reduce its bulk. This is why there have been proposed (EP 0 958 951) mixing devices which use a shut-off plate arranged roughly at right angles to the air stream and sliding in slideways of the casing. Although it has the advantage of being compact, this device does have numerous disadvantages.
Sealing is afforded by a seal. The squashing of this seal generates a high friction force upon sliding of the plate in the slideway. This friction force entails a very high control force.
The use of a single shut-off element does not allow the amount of hot air and cold air to be adjusted in order to meet the required temperature conditions for intermediate positions of the control. Furthermore, given that the shut-off plate is in one piece, the regions of the matrix which lie behind it are not crossed by the air stream. This arrangement does not encourage good mixing of the air and aerothermal optimization of the heating apparatus.
The need to seal the device dictates the use of tight tolerances on the components and fits. These tolerances are difficult to achieve with the methods and materials generally used for producing heating and air-conditioning apparatuses. The cost of manufacture is therefore increased.
The subject of the present invention is a mixing device which solves these disadvantages. These objectives are achieved, according to the invention, through the fact that the mixing device comprises at least one panel comprising a perforation arranged in the hot air duct and a shut-off plate that can move between an open position in which it does not cover the perforation in the panel and a shut-off position in which it shuts off the perforation in the panel; at least one shutter for adjusting the passage cross section of the cold air duct that can move between an open position and a shut-off position, and a control mechanism for controlling, in synchronism, the movement of the shut-off plate and the movement of the shutter for adjusting the passage cross section of the cold air duct between their open position and their shut-off position.
These movements are synchronized in such a way that the passage cross section of the hot air duct increases when the passage cross section of the cold air duct decreases, and vice versa. Furthermore, the hot air duct is completely open when the cold air duct is completely closed, and vice versa.
Thus, the device comprises two independent adjusting elements, one for the hot air duct and the other for the cold air duct. The design of these elements and the logic dictating their movement make it possible for all the characteristics of the air mixing function to be satisfied in an optimum manner. It guarantees flexibility of adjustment of the quantity and of the localization of the air stream to be injected into the hot air duct and into the cold air duct. It makes it possible to produce highly permeable hot air and cold air circuits, that is to say circuits in which the pressure drop is low. The air stream from the blower, or from the evaporator if the heating apparatus has one, passes directly through the matrix without undergoing any significant change in direction.
This device guarantees perfect sealing of the cold air circuit. The latter is indeed shut off by a specific closure shutter, which can be adjusted independently of that of the hot air circuit. The movement of this shutter is preferably a rotational movement which, at the end of travel, generates a closure force in the direction of the shutter bearing surfaces.
As a preference, the panel comprises a number of perforations and the shut-off plate has a number of cutouts, the perforations in the panel and the cutouts in the shut-off plate being arranged with respect to one another in such a way that the hot air duct is shut off when the shut-off plate is in its shut-off position.
By virtue of this preferred feature, the air let into the hot air duct is distributed over the entire frontal surface of the matrix whereas, in the prior art mentioned earlier, there are regions of the matrix which the air stream does not reach.
Furthermore, the number, location, direction, shape and dimensions of the perforations in the panel and of the cutouts in the shut-off plate constitute parameters that can be altered in order to aerothermally optimize the apparatus. Furthermore, this arrangement allows the shut-off plate a small-amplitude excursion, less than half the height of the matrix. This small-amplitude excursion makes it easier for the mixing device to be incorporated into the low-volume apparatuses. It also makes it possible to observe a significant distance between the bottom of the shut-off plate and the end of the casing. This arrangement has the advantage of generating a large working volume for creating a tray for collecting condensate from the evaporator, to make it easier for this condensate to flow toward a discharge orifice and avoid placing the shut-off plate sealing system in contact with the condensate. This then gets around the problems of smell which may result from the presence of this condensate. There is an air passage possibility allowing good supply to the hot air and cold air circuits.
Also as a preference, the shut-off plate moves in a combined movement o
Boles Derek
Liniak Berenato & White
Valeo Climatisation
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