Ventilation – Vehicle – Having inlet airway
Reexamination Certificate
2000-08-22
2002-08-13
Joyce, Harold (Department: 3744)
Ventilation
Vehicle
Having inlet airway
Reexamination Certificate
active
06431977
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to an air inlet for a heating or air-conditioning system of a motor vehicle having at least one air inlet opening which is arranged in an area below a windshield in which a ram pressure occurs during the drive of the motor vehicle. Certain embodiments relate to such system having at least one air inlet opening which, in an area below a windshield, is arranged laterally of a vehicle center plane.
In the case of the known air inlets, a blower is used when the vehicle is stopped and at a low speed of the vehicle in order to generate an air throughput in the interior of the motor vehicle, while, as the driving speed increases, a ram pressure is generated in the area below the windshield—the so-called cowl—by means of which ram pressure the outside air automatically enters the heating or air-conditioning system. This ram pressure is a function of the speed, so that, at higher vehicle speeds, the air inlet must be throttled in order to counteract undesirably high flow rates in the vehicle interior. The throttling can take place manually, as known, for example, from German Patent Document DE 44 14 036 A1 (corresponding to U.S. Pat. No. 5,645,479), or by means of an automatic speed-dependent control. The throttling causes additional expenditures, particularly in the case of the automatic control which is to be preferred for reasons of comfort and where precise low-hysteresis kinematics are required in order to achieve a precisely reproducible position of the throttle valve because only very small passage cross-sections remain at high vehicle speeds. In addition, the cross-sections, which are highly throttled at higher vehicle speeds, may be the starting point of noises in the air inlet area.
In many vehicles, the air inlets are arranged in the lateral frame area of the windshield because a lower ram pressure occurs here, as illustrated, for example, in the representation of FIGS. 1 and 2 of French Patent Document FR 1,165,665 A. Nevertheless, at higher vehicle speeds, as a rule the ram pressure is so high also in the case of exterior air inlets that a throttling is required.
It is an object of the invention to provide a simply constructed air inlet for a motor vehicle, in the case of which the ram pressure is essentially independent of the vehicle speed.
This object is achieved according to certain preferred embodiments of the invention by providing an air inlet for a heating or air-conditioning system of a motor vehicle, having at least one air inlet opening which is arranged in an area below a windshield in which a ram pressure occurs during the drive of the motor vehicle, wherein a device is provided which partitions off the air inlet opening with respect to an area with a relatively high ram pressure and simultaneously causes the air supply from an area of the motor vehicle in which a relatively low pressure exists during the drive of the motor vehicle. This object is achieved according to other preferred embodiments by providing an air inlet for a heating or air-conditioning system of a motor vehicle, having at least one air inlet opening which, in an area below a windshield, is arranged laterally of a vehicle center plane, wherein a device is provided between the air inlet opening and the vehicle center plane, which device partitions off the air inlet opening with respect to air flows extending approximately transversely to a vehicle forward driving direction.
According to certain embodiments of the invention, the air inlet opening is insulated with respect to the area in which an excess pressure toward the vehicle interior forms during the drive of the motor vehicle, and the outside air is fed from an area with a low pressure level, such as the lateral area of the cowl of the vehicle body where, during the driving of the motor vehicle, a lower ram pressure occurs with respect to the vehicle interior (see French Patent Document FR 1,165,665 A). As the result, the pressure level at the air inlet opening is reduced, so that, as the vehicle speed rises, the air throughput does not increase or increases only relatively slightly. In view of the fact that, at higher driving speeds, a slightly increased air throughput is even desirable, in the case of the air inlet according to the invention, a ram air flap can be eliminated.
The system according to the invention comprises, for example, of a covering over the air inlet opening which is open only toward a side area of the vehicle body.
In modern motor vehicles, the air inlet openings are often situated in a covered manner in the area below the rearward end sections of the front flap. In the case of certain preferred embodiments of the invention, the invention can be implemented in a particularly simple manner by inserting a separating wall for sealing off the gap between the front flap and the windshield. Naturally, a partition of the duct cross-section toward the vehicle center is also required in order to insulate the air inlet opening with respect to this area of a high ram pressure. The partition according to the invention is hardly visible from outside the vehicle and can be provided at low expenditures in the case of new vehicle models as well as retrofitted in the case of existing vehicles.
Below the rearward end section of the front flap, the windshield wipers for cleaning the windshield are in many cases arranged in a hidden manner. In the case of windshield wipers constructed in pairs, the driving axis of the driver-side wiper is as a rule arranged on the exterior of the vehicle so that, in the case of a construction of the invention according to certain preferred embodiments, the partition extending above the air inlet opening must be provided with openings for the passing-through of the windshield wiper. In certain preferred embodiments, it is provided that an air inlet on the driver side be eliminated and a correspondingly dimensioned air inlet be provided only on the front passenger side.
While naturally a flow extending approximately in the driving direction flows against the center area of the windshield of a motor vehicle and the air flow flows off almost completely via the vehicle roof, so that the highest ram pressure occurs in the center below the windshield, a lateral flow also increasingly takes place around the lateral areas of the windshield because the air flow flows partially off in the direction of the vehicle side areas. As a result, a decreasing ram pressure occurs in the direction of the exterior side of the vehicle. As a result of the pressure difference between the vehicle center and the exterior side of the vehicle, an air flow extending transversely to the driving direction occurs in the area below the windshield. Here preferred embodiments of the invention provide a device for partitioning off this flow extending transversely to the driving direction. As a result, an exterior air inlet opening is insulated from the “transverse flow” and thus a clear reduction is achieved of the dependence of the air throughput in the heating or air-condition system from the driving speed.
In the case of motor vehicles whose air inlet openings are arranged in a hidden manner in the area below the rearward end sections of the front flap, preferred embodiments of the invention can be implemented in a particularly simple manner by inserting a transverse wall into the duct below the windshield formed by the front-flap and other adjacent components. This division of the duct is hardly visible from outside the vehicle and can be provided at low expenditures in the case of new vehicle models as well as retrofitted in the case of existing vehicles.
In addition to the partitioning walls according to the above described embodiments, further partitioning can be provided, for example, if the air inlet opening is not situated sufficiently far on the exterior side of the vehicle. Such additional partitioning walls also prevent backflows from the windshield and disturbing air swirls at the air inlet opening.
By means of a further development of preferred embodiments of the
Bayerische Motoren Werke Aktiengesellschaft
Boles Derek S.
Crowell & Moring LLP
Joyce Harold
LandOfFree
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