Abstract:
A ventilation controlling apparatus for feeding windshield defrost outlets and side window demist outlets in motor vehicles with one or more air passages and respective doors for each outlet. The apparatus supports a mode in which the demist door opens up to a predefined angle without the defrost door opening, too, with the predefined angle depending on the design of a cam attached to the demist door and a pin engaged with that cam and attached to the defrost door.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a ventilation controlling apparatus and a method for controlling ventilation, particularly for feeding defrost and side window demist outlets in motor vehicles. 
         [0002]    In motor vehicles at moderate outside temperatures (up to 25° C.) passengers usually prefer using the bi-level ventilation mode of a heating, ventilation and air conditioning (HVAC) unit. In this mode vent and floor outlets are at least partially open. When air humidity is high as it tends to be the case the more passengers are inside the side windows are prone to fog up. To keep passengers comfortable in this situation the side windows demist outlets have to be open while the defrost outlets remain closed. Otherwise there could emerge a fogged up spot on the outside of the windshield. 
         [0003]    There are different approaches known for solving this problem. One is the usage of a film door inside the ventilation controlling apparatus as in US 2002/0197951 A1. A film door is a film which is moved by two coils, one of them spring loaded. The film has openings stamped out such that the cross sectional open area allows for air to flow through. A ventilation controlling apparatus with such a film door can easily be designed so it solves the aforesaid problem. The disadvantage is its need for space in order to package the two coils as well as the challenge to seal the moving film reliably. 
         [0004]    Furthermore the sealing can lead to a wiping or scratching noise during operation which is annoying for the passengers. 
         [0005]    Another approach as in DE 197 57 280 A1 uses moving doors or butterfly valves equipped with sealing foam wiping on a surface and thus keeping air from flowing to the defrost outlet while the synchronously turned door for the side window demist outlet is already open in this mode. However the wiping or scratching noise problem applies to this solution, too. 
       SUMMARY OF THE INVENTION 
       [0006]    It is accordingly an object of the invention to provide an improved ventilation controlling apparatus and a method for controlling ventilation to allow for providing an air flow to a side window demist outlet in bi-level mode while the defrost outlet is kept closed. 
         [0007]    With the foregoing and other objects in view there is provided, in accordance with the invention a ventilation controlling apparatus, comprising:
       a casing for forming at least one sealable first air passage and at least one sealable second air passage, said air passages separated from each other by at least one partition wall;   each of said first air passages sealable by turning one respective first door attached to a pivoted first shaft to a respective door stop position;   each of said second air passages with one respective second door attached to a pivoted second shaft to a respective door stop position;   a drive element attached to said first shaft;   a mechanical link causing the angle of said second shaft to be a function of the angle of said first shaft in such a way that said second door remains in its respective door stop position as long as said first door has an angle ranging from its respective door stop position where it seals tight said first air passage to a predefined aperture angle and that said second door opens when said first door has an angle exceeding said predefined aperture angle.       
 
         [0013]    The predefinition of this predefined aperture angle is achieved by an appropriate design of said mechanical link. Each shaft can be one-piece or split so its respective door is attached to two of its sections interrupted in the region of the door, so the door has to perform the task of the shaft here. Furthermore a shaft can be made in one piece with its respective door especially if they are made of a mouldable or castable material like metal or plastics: In the same way it is possible to make the drive element in one piece with the first shaft. Alternatively shafts, doors and drive element can be single parts, too. 
         [0014]    In other words, according to the invention, when the first door is in its door stop position the second will be, too. The second door will stay so, as long as the first door is turned by means of the drive element between its door stop position and a predefined aperture angle. As soon as the first door is moved beyond that predefined aperture angle the second door will open, too. When feeding vehicle side window demist outlets with air flow from the first door and a windshield defrost outlet with air from the second one and turning the drive element to said predefined aperture angle by selecting bi-level mode, the side window demist outlets are given an air flow while the windshield defrost door is not, thus avoiding fogging of the side windows and fog spots on the outside of the windshield. 
         [0015]    According to another feature of the invention, the drive element is a gear in order to ease setting its angle. 
         [0016]    According to yet another feature of the invention, the mechanical link comprises a cam and a pin engaged in the cam, so that turning of the first shaft or the attached drive element causes the second shaft to turn in a way predefined by the cam track. A cam is one of the easiest ways to achieve this behavior. The cam can be attached to the first shaft, to the drive element or to one of the first doors for this purpose and can also be made in one piece together with the part to which it is attached or incorporated in the drive element. The pin can be attached to one of the second doors or to a lever again attached to the second shaft. Again it is possible to make the pin in one piece with the part to which it is attached and so it is for the lever. Alternatively cam, pin and lever can be single parts, too. 
         [0017]    In an alternative embodiment of the invention, the second shaft or a part of it is arranged coaxially inside a hollow section of the first one or vice versa. The mechanical link comprises a loaded spring engaged with both shafts in this case. This way the ventilation controlling apparatus can be built compactly. 
         [0018]    According to a preferred feature of the invention, the shafts parallel each other, which saves space. 
         [0019]    In a particularly preferred embodiment of the invention, the ventilation controlling apparatus comprises two first air passages and two second air passages with their respective doors separated by partition walls from each other, wherein the two first doors are attached to a common first shaft and the two second doors to a common second shaft, so they turn synchronously. 
         [0020]    According to another feature of the invention, the two second air passages are arranged adjacently to each other in a central region of the casing and the two first air passages are arranged beside them adjacently to one second air passage and to one outboard wall of the casing each, so the apparatus is fit for providing an air flow to two or more central outlets by the second air passages and one lateral outlet on both sides by the first air passages. According to yet another feature of the invention, the first shaft has its bearings in two outboard walls of the casing and the second shaft has its bearings in two partition walls between first and second air passages. 
         [0021]    The preferred use of the ventilation controlling apparatus is with a motor vehicle, wherein the first air passages feed the side window demist outlets and the second air passages feed the defrost windshield outlet. 
         [0022]    The predefined aperture angle is preferably within a range of 5° to 60°, particularly 10° to 40°. 
         [0023]    In a preferred embodiment of the invention, the predefined angle equals 18° as required by some car manufacturers&#39; specifications. 
         [0024]    The angle of the drive element and thus the first shaft is preferably controlled by the ventilation mode selected by the vehicle operator so that the first door is turned to its predefined aperture angle when bi-level mode is selected. When vent mode is selected, the first door is turned to its door stop position to keep air from flowing to the side window demist outlets and thus the first door remains closed, too. 
         [0025]    Although the invention is illustrated and described herein as embodied in a ventilation controlling apparatus, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0026]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1A  is a bottom view of a first embodiment of a ventilation controlling apparatus according to the invention with two first doors, one second door, a cam attached to the first shaft and a pin attached to the second door and engaged in the cam in a state with all doors closed; 
           [0028]      FIG. 1B  is a side view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0029]      FIG. 1C  is a front view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0030]      FIG. 1D  is another side view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0031]      FIG. 1E  is a top view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0032]      FIG. 1F  is a back view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0033]      FIG. 1G  is a perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A ; 
           [0034]      FIG. 2A  is a bottom view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A  in another state with the first doors partially open and the second door closed; 
           [0035]      FIG. 2B  is a side view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0036]      FIG. 2C  is a front view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0037]      FIG. 2D  is another side view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0038]      FIG. 2E  is a top view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0039]      FIG. 2F  is a back view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0040]      FIG. 2G  is a perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 2A ; 
           [0041]      FIG. 3A  is a bottom view of the embodiment of a ventilation controlling apparatus according to  FIG. 1A  in yet another state with all doors open; 
           [0042]      FIG. 3B  is a side view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0043]      FIG. 3C  is a front view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0044]      FIG. 3D  is another side view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0045]      FIG. 3E  is a top view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0046]      FIG. 3F  is a back view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0047]      FIG. 3G  is a perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 3A ; 
           [0048]      FIG. 4A  is a perspective view of a preferred embodiment of a ventilation controlling apparatus according to the invention with two first doors, two second doors, a cam attached to the drive element, a lever attached to the second shaft with an attached pin engaged in the cam in a state with all doors closed; 
           [0049]      FIG. 4B  is another perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 4A ; 
           [0050]      FIG. 5A  is a perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 4A  in a state with the first doors partially open and the second doors closed; 
           [0051]      FIG. 5B  is another perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 5A ; 
           [0052]      FIG. 6A  is a perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 4A  in a state with all doors open; 
           [0053]      FIG. 6B  is another perspective view of the embodiment of a ventilation controlling apparatus according to  FIG. 6A ; and 
           [0054]      FIG. 7  is a perspective view of a cut-out of an alternative embodiment of a ventilation controlling apparatus with a first shaft arranged inside a second shaft, both engaged with a loaded torsion spring. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0055]    Referring now to the figures of the drawings in detail and first, particularly, to  FIG. 1A  thereof, there is shown the bottom view of a first embodiment of a ventilation controlling apparatus  1  according to the invention with two first doors  2 , one second door  3  and a cam  4  attached to the first shaft  5  to which the first doors  2  are also attached. A pin  6  is attached to the second door  3  and engaged in the cam  4 . The air passages (not shown in their entirety) sealable by the doors  2 ,  3  are separated by partition walls  7  where a second shaft  8  (only shown in the top view in  FIG. 1E  and the perspective view in  FIG. 1G ) molded in one piece with the second door  3  has its bearings. 
         [0056]    The first shaft  5  is turned by means of the drive element  9  to an angle which causes the first doors  2  attached to that first shaft  5  to take a so called door stop position, meaning they are aligned horizontally where they seal tight their respective air passages, which are designed accordingly. This becomes clear when regarding  FIGS. 1B and 1D , which are side views of the ventilation controlling apparatus  1  and  FIGS. 1C and 1F  which are front and back view, respectively, thereof. 
         [0057]    In  FIG. 1G , which is a perspective view of the ventilation controlling apparatus  1 , it is shown that the cam  4  is designed to hold the pin  6  in a position in this state where it keeps the second door  3  closed and aligned horizontally, too. The first doors  2  supply side window demisting outlets of a motor vehicle with an air flow. The second door  3  feeds the defrost windshield outlet. 
         [0058]    In the condition described here and shown in  FIG. 1A to 1G  neither one of these outlets is given an air flow, as it is required when a vehicle operator selects, e.g., vent mode. There is a conventional means for setting an angle of the drive element  9 , which can be a gear, for instance, according to the ventilation mode selected. 
         [0059]    When the operator selects bi-level mode, this causes the drive element  9  to be turned to a predefined aperture angle α, preferably within a range of 5° to 60°, e.g. 18°, as shown in  FIG. 2A to 2G , which show the same views as in  FIG. 1A to 1G  but with that different angle. The predefinition for α is achieved by an appropriate design of the cam  4 . The first shaft  5  attached to the drive element  9  and first doors  2  take a position partially opening the first doors  2  and thus allowing an air flow to the side window demist outlets. This becomes particularly clear when regarding  FIGS. 2B ,  2 D and  2 G. The second door  3  is kept closed because the cam  4  is designed to keep the pin  6  in the respective position up to this predefined aperture angle α, which is best shown in  FIG. 2G . 
         [0060]    When the operator selects, e.g., defrost mode, the drive element  9  is turned to an angle beyond that predefined aperture angle α as shown in  FIG. 3A to 3G , which again show the same views of the ventilation controlling apparatus as in  FIG. 1A to 1G  but that angle being bigger than α. The first doors  2  are opened wider than in  FIG. 2A to 2G  and the cam  4  pushes the pin  6  and thus causes the second door  3  to open, too. 
         [0061]    The first shaft  5  has its bearings in the outboard walls of the casing (not shown in detail). In this embodiment of the invention the shafts  5 ,  8  are both one-piece, but they could alternatively be split so their respective doors  2 ,  3  would be attached to two sections of a shaft  5 ,  8  interrupted in the region of the door  2 ,  3 , so the door  2 ,  3  would have to perform the task of the shaft  5 ,  8  here, transmitting torque for instance. Although the second shaft  8  is made in one piece with the second door  3  and the pin  6 , they could be separate parts, too. The same applies to the first shaft  5 , the first doors  2 , the cam  4  and the drive element  9  attached thereon. 
         [0062]      FIG. 4A  shows a perspective view of a preferred embodiment of a ventilation controlling apparatus  1  according to the invention. Two second doors  3  are cast in one piece with the sections of a second shaft  8 , which has its bearings in the partition walls  7  between the second and the first air passages and a lever  10  with a pin  6  is located on one end of the second shaft  8  outside one of these partition walls  7 . Two first doors  2  are attached to a first shaft  5  which has its bearings in the outboard walls of the casing and which has a drive element  9  with an incorporated cam  4  at one end, in which the pin  6  is engaged as, best shown in  FIG. 4B , which is a perspective view from another point of view. 
         [0063]    The drive element  9  can be a gear. In the condition shown here, i.e., when vent mode is selected by the vehicle operator, the first shaft  5  is turned by means of the drive element  9  to an angle which causes the first doors  2  to take a horizontal door stop position where they seal tight their respective air passages. The cam  4  is designed to hold the pin  6  in a position in this state where it keeps the second doors  3  closed too. The first doors  2  supply the side window demisting outlets of a motor vehicle with an air flow. The second doors  1  feed the defrost windshield outlet(s). In the condition described here and shown in  FIGS. 4A and 4B , neither one of these outlets is given an air flow. 
         [0064]    When the operator selects bi-level mode and thus causes the drive element  9  to be turned to a predefined aperture angle α, e.g. 18°, as shown in  FIG. 5A , the attached first shaft  5  and first doors  2  will take a position partially opening the first doors  2  and thus allowing an air flow to the side window demist outlets.  FIGS. 5A and 5B  show the ventilation controlling apparatus from the same points of view as in  FIGS. 4A and 4B , but with the different angle. The second doors  3  are kept closed, because the cam  4  is designed to keep the pin  6  in the respective position up to this predefined aperture angle α(see  FIG. 5B ). 
         [0065]    When the operator selects, e.g., defrost mode, the drive element  7  is turned to an angle beyond that predefined aperture angle α, as shown in  FIGS. 6A and 6B . These figures show the ventilation controlling apparatus from the same points of view as in  FIGS. 4A and 4B  but with an angle bigger than the predefined aperture angle α. The first doors  2  are opened wider than in  FIGS. 5A and 5B , and the cam  4  pushes the pin  6  and thus causes the second doors  3  to open, too. 
         [0066]      FIG. 7  shows a portion of an alternative embodiment of a ventilation controlling apparatus  1  according to the invention, with a first shaft  5  arranged coaxially inside a second shaft  8 , both engaged with a loaded torsion spring  11  by appropriate tappets  12 . 1  and  12 . 2 . The loaded spring has to have a prestressing that causes the second door (not shown) attached to the second shaft  8  to remain in its door stop position when the first door (not shown) is opened up to the predefined aperture angle α. In other words α is predefined by the prestress of that loaded spring  11 , so the loaded spring is relaxed when the angle of the first door is equal to the predefined aperture angle α.