Abstract:
A tire adjustment system and utilization means therefor includes a vehicle having at lone or more electronic vehicle control systems such as an anti-lock brake system; steering wheel control system, electronic stability system; suspension control system; global positioning system. An electronic valve system is mounted to operatively adjust on a tire-by-tire basis the inflation pressure within each tire cavity responsive to an electronic input signal from at least one of the vehicle control systems. The inflation adjustment of each tire alters the tire tread footprint configuration to optimally correlate with one or more identified current road condition(s) traversed by the vehicle.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to a vehicle system having air maintenance capability for adjusting inflation in vehicle tires and, more specifically, to a vehicle system and method for automatically making such adjustments. 
       BACKGROUND OF THE INVENTION 
       [0002]    Changes in road conditions can cause the performance of the vehicle tires to become less than satisfactory and result in driver dissatisfaction. For example, tires on a vehicle are optimally expected to contribute to maximum fuel efficiency on dry, straight roads; maximum handling performance is desired on roads having severe curves; and wet traction performance is sought on water covered roads. To achieve a tire having a versatility to perform satisfactorily on all possible road conditions has to date proven problematic. 
       SUMMARY OF THE INVENTION 
       [0003]    According to an aspect of the invention, a tire adjustment system and utilization means for a tire-mounted vehicle includes a vehicle having at least one electronic vehicle control system taken from the group: anti-lock brake system; steering wheel control system, electronic stability system; suspension control system; global positioning system; and an electronic valve system mounted to operatively adjust on a tire-by-tire basis the inflation pressure within each tire cavity responsive to an electronic input signal from at least one of the vehicle control systems. 
         [0004]    In another aspect, the vehicle control system operatively detects in real time from a set of predetermined identifiable road conditions one or more identified current road condition(s) traversed by the vehicle and operatively actuates the electronic valve system to adjust the inflation pressure within each tire to an optimal inflation for the identified current road condition. 
         [0005]    In a further aspect, the electronic valve system includes one or more pairs of coupled compressor units and valve members, the compressor unit pumping air responsive to an electronic input signal through the valve member and into a tire cavity. 
         [0006]    The set of predetermined identifiable road conditions, according to another aspect of the invention, includes road curvature, road surface condition, and road friction characteristics and the electronic valve system adjusts the inflation pressure within each tire to operatively reconfigure the tire tread into an optimal tire tread performance configuration for the identified current road condition(s). 
       Definitions 
       [0007]    “Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW) multiplied by 100 percent for expression as a percentage. 
         [0008]    “Asymmetric tread” means a tread that has a tread pattern not symmetrical about the center plane or equatorial plane EP of the tire. 
         [0009]    “Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire. 
         [0010]    “Chafer” is a narrow strip of material placed around the outside of a tire bead to protect the cord plies from wearing and cutting against the rim and distribute the flexing above the rim. 
         [0011]    “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. 
         [0012]    “Equatorial Centerplane (CP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of the tread. 
         [0013]    “Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure. 
         [0014]    “Groove” means an elongated void area in a tire dimensioned and configured in section for receipt of a an air tube therein. 
         [0015]    “Inboard side” means the side of the tire nearest the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
         [0016]    “Lateral” means an axial direction. 
         [0017]    “Lateral edges” means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the lines being parallel to the equatorial centerplane. 
         [0018]    “Net contact area” means the total area of ground contacting tread elements between the lateral edges around the entire circumference of the tread divided by the gross area of the entire tread between the lateral edges. 
         [0019]    “Non-directional tread” means a tread that has no preferred direction of forward travel and is not required to be positioned on a vehicle in a specific wheel position or positions to ensure that the tread pattern is aligned with the preferred direction of travel. Conversely, a directional tread pattern has a preferred direction of travel requiring specific wheel positioning. 
         [0020]    “Outboard side” means the side of the tire farthest away from the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
         [0021]    “Peristaltic” means operating by means of wave-like contractions that propel contained matter, such as air, along tubular pathways. 
         [0022]    “Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire. 
         [0023]    “Rib” means a circumferentially extending strip of rubber on the tread which is defined by at least one circumferential groove and either a second such groove or a lateral edge, the strip being laterally undivided by full-depth grooves. 
         [0024]    “Sipe” means small slots molded into the tread elements of the tire that subdivide the tread surface and improve traction, sipes are generally narrow in width and close in the tires footprint as opposed to grooves that remain open in the tire&#39;s footprint. 
         [0025]    “Tread element” or “traction element” means a rib or a block element defined by having a shape adjacent grooves. 
         [0026]    “Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0028]      FIG. 1  is a perspective view of a vehicle employing the subject adjustment system. 
           [0029]      FIG. 2  is a diagrammatic view of the system. 
           [0030]      FIG. 3  is a plan view of a tread footprint in a low inflation setting. 
           [0031]      FIG. 3B  is a plan view of a tire tread footprint in a normal inflation setting. 
           [0032]      FIG. 3C  is plan view of a tire tread footprint in a raise inflation setting. 
           [0033]      FIG. 4  is a diagrammatic view of the system in a one valve system configuration. 
           [0034]      FIG. 4A  is a sectional view through the valve unit of  FIG. 4  taken along the line  4 A- 4 A. 
           [0035]      FIG. 5  is a diagrammatic view of the system in a two valve system configuration. 
           [0036]      FIG. 5A  is a section view through the valve assembly of  FIG. 5  taken along  5 A- 5 A. 
           [0037]      FIG. 5B  is a section view through the exhaust valve of  FIG. 5  taken along  5 B- 5 B. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0038]    Referring initially to  FIGS. 1 and 2 , a vehicle  10  of conventional construction is mounted on tires  12 ,  14 ,  16 , and  18 . While a passenger car configuration is shown, the subject invention can likewise find application in alternate vehicle categories such as off-road equipment and commercial trucks. The vehicle  10  is conventionally equipped with an on-board computer  20  and one or more systems are incorporated into the vehicle such as an anti-lock brake system (ABS)  22 , an electronic suspension program (ESP)  24  and/or a global positioning system (GPS)  26 . Such systems are electronically connected to the computer  20  and provide control of vehicle systems or generation of user-enabling information for vehicle operation. For example, the ABS system provides for control of vehicular braking in certain operational conditions; the ESP provides an automated suspension adjustment to the vehicle; and the GPS information to the operator useful for route calculation and positioning. 
         [0039]    As seen in  FIGS. 4 and 5 , the tires  12 ,  14 ,  16 , and  18  are of conventional construction, each having a pair of sidewalls  42 ,  44  extending from a respective bead  48 ,  50  to a circumferential tire tread  46 . The tire encloses a cavity  52  that is inflated to a desired air pressure and each tire mounts to a rim  54 . During operation of the vehicle, each tire forms a tire footprint against the ground surface. As seen in  FIGS. 3A through 3C , the surface area of the tire footprint as measured in millimeters varies according to the inflation level of the tire;  FIG. 3A  showing the footprint  32  generated on opposite sides of the tire centerline CL from a low inflated tire;  FIG. 3B  showing the footprint  38  generated on opposite sides of the tire centerline CL from a normal inflated tire; and  FIG. 3C  showing the footprint  40  generated on opposite sides of the tire centerline CL from a raised inflation tire. The surface area of footprint  32  is greater than footprint  38  which is then greater than footprint  40 . In general, the greater a tire inflation level, the smaller a footprint generated by the tread pattern will be produced. 
         [0040]    The tire tread forming the footprints of  FIGS. 3A through 3C  is constructed from a pattern of grooves  34  and siping elements  36 . Differing tire inflation levels generate different footprints by the tread pattern as seen from  FIGS. 3A through 3C , each of which being preferred for a respective set of road and road surface conditions. For example, the footprint  32  of  FIG. 3A , being the largest footprint created by an underinflated tire, will result in a tire exhibiting moderate rolling resistance performance, standard handling performance, and excellent dry/wet gripping characteristics. On a road following a curved path and/or wet surface conditions, the footprint of  FIG. 3A  may be preferred. The footprint  38  of  FIG. 3B  produced by a normally inflated tire, on the other hand, will result in a tire exhibiting normal level of rolling resistance, outstanding handling, and normal level of wet/dry gripping. The footprint  40  of  FIG. 3C  produced by an raised inflation level will be more rounded and result in a tire exhibiting very good rolling resistance and handling and wet/dry grip at a normal level. Depending on the road topography and surface conditions, accordingly, one of the three footprint configurations may be deemed preferable over the other two. It is self understood that also intermediate footprint configurations might be desirable and inflation pressure adjusted to achieve those. 
         [0041]    The electronic systems of a vehicle such as ABS and ESP and GPS can be utilized to identify the road topography and surface conditions encountered by a vehicle in real time. A set of predetermined identifiable road conditions may be programmed into the computer  20 . The ABS, ESP, and GPS systems may be used to input road condition information into the computer in real time from which an identified current road condition may be ascertained from the stored set of identifiable road conditions. Once an identification of the current road condition (topography and surface conditions), a preferred footprint for each of the tires may be determined best suited to meet the current road condition. 
         [0042]    Pursuant to the invention, with reference to  FIGS. 4 and 4A , each of the tires  12 ,  14 ,  16 , and  18  is equipped with one or more remotely controlled electronic valve systems  30 . The valve system(s)  30  are used to adjust the inflation pressure of each individual tire position, according to the input of the vehicle electronic control system (ABS, ESP, steering wheel, GPS route calculation and position location). The valve system  30  may be a single valve system for inputting and outputted air from the tire cavity  52  as shown in  FIGS. 4 and 4A , or for faster response there can be one valve for inflating and a separate valve for deflating the tire quickly according to the suspension control of the vehicle as shown in  FIGS. 5 ,  5 A and  5 B. In the one valve system, the valve system includes an elongate valve body  62  mounted to extend through the rim  54 . The body  62  includes an enlarged retention cap  64  abutting an outer surface of the rim  54 , a retainer flange  66  abutting an inner surface of the rim  54  and the body  62  extends a forward end  68  into the cavity  52 . An axial air passageway  70  extends through the body  62  and allows external air to flow through the body  62  and into the cavity  52  as shown by arrow  58  and allow air to flow in a reverse direction through the body  62  from the cavity  52  as shown by arrow  60 . 
         [0043]    In the valve body  62 , a small pump/compressor  72  coupled to an open/shutoff valve  74  of a type commercially available are housed. The pump/compressor is electronically controlled to increase or reduce tire inflation by the directional passage of air through the valve  74  into and from the tire cavity. The electric power for the compressor  72  may be supplied through wire or wireless known techniques. 
         [0044]      FIGS. 5 ,  5 A, and  5 B show a two valve system in which an intake valve member shown in  FIG. 5B  incorporates an intake valve  86  coupled to transceiver  80  opens to allow air to flow into the cavity  52  as indicated at arrow  58 . A second valve member is mounted into the rim  54  and includes the pump/compressor  84 , valve component  82 , and a transceiver  80 . The second valve member shown in  FIG. 5A  opens to allow air to flow through the valve passageway in direction  60  to reduce the air pressure within the tire. More valve assemblies  30  than the number shown may be employed to increase the speed of inflation adjustment if desired. 
         [0045]    From the foregoing, it will be appreciated that the footprint adjustment made to each tire by changing inflation pressure accomplishes multiple advantages. The performance, environmental and safety of the vehicle is enhanced by real time adjustment to tire inflation pressure. Through the inflation adjustment system, the vehicle may be made to operate at maximum fuel efficiency when road topography and surface conditions permit. On curvy roads, the system adjusts tire inflation pressure and footprint to allow the vehicle to operate at maximum handling characteristics. During rain or on wet road conditions, the system adjusts tire inflation pressure and footprint to operate a maximum gripping level. In addition, the system will be useful to keep a desired inflation pressure, or footprint, of the tires even in the case of a defective tire which might lose air. In such case, the inflating compressor/pump will pump air into the tire more frequently or continuously to compensate for the air loss due to a leak. Thus, this system also contributes to extended mobility of the vehicle. 
         [0046]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.