Abstract:
A method and system for extending the range of run-flat tires by providing ride height control. When the vehicle has a damaged tire or tires the ride height of an appropriate suspension system(s) is capable of being adjusted to achieve a level attitude for the vehicle thus preventing destructive loads from being placed on the damaged run-flat tire(s).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. application Ser. No. 11/430,771, filed May 9, 2006 and incorporated herein by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT  
       [0002]     This invention was made and funded by the U.S. Government, specifically by the U.S. Army Tank-Automotive &amp; Armaments Co. under Contract W56HZV-05-9-0002. The U.S. Government has certain rights in the invention. 
     
    
     FIELD OF THE INVENTION  
       [0003]     The present invention relates generally to the field of vehicles, and, more particularly, to extending the range of run-flat tires.  
       BACKGROUND OF THE INVENTION  
       [0004]     The majority of vehicles, including some tactical military vehicles, travel on inflatable tires that are vulnerable to damage. Damage may arise from a number of sources in a military environment, including munitions projectiles such as enemy fire, rocks, pot holes, and sharp objects lying in the road. Commonly, the result of an encounter of a tire with such an object is a deflated tire.  
         [0005]     The response to a deflated tire may include two options. The tire may be replaced at the site where the damage occurred. However, safety issues may preclude replacement at the site. A military vehicle operating under enemy fire lacks an option of stopping to replace a damaged tire and must continue its movement to leave the hostile area.  
         [0006]     A second option is continuation of travel, albeit at a reduced speed, to a location having conditions more suitable for replacing the damaged tire. Making this possible are conventional run-flat tires, which are capable of running flat when deflated. Generally, run-flat tires have a run-flat insert that allows rotation of the wheel on which the run-flat tire is mounted while support for the vehicle continues.  
         [0007]     However, run-flat tires by themselves are just a stop gap measure. In addition to imposing a limitation on the speed of the vehicle, run-flat tires have a limited range. Since the radius of a deflated run-flat tire is considerably less than the radii of the remaining inflated and undamaged tires, the vehicle tilts toward the deflated run-flat tire and, as a result, shifts part of the load previously carried by the inflated tires onto the now deflated run-flat tire. Even if such load shifting and side loading are design considerations for the tire, such forces may still restrict the operating range of a deflated run-flat tire.  
         [0008]     Thus, in vehicles utilizing run flat inserts in their tires, the range such a vehicle can travel with a flat tire is limited due to the eventual total destruction of the tire. This destruction is accelerated by the fact that once a tire has been flattened the vehicle assumes a tilted attitude toward that flat and thus shifting additional weight and side loads onto the already damaged tire.  
         [0009]     For the above reasons, it would be beneficial to provide a method and system to extend the range of a vehicle operating on run-flat tires before destruction of the tire or insert occurs rendering the vehicle immobile.  
       SUMMARY OF THE INVENTION  
       [0010]     The needs of the invention set forth above as well as further and other needs and advantages of the present invention are achieved by the embodiments of the invention described herein below.  
         [0011]     The present invention provides a method to control the vehicle&#39;s attitude to prevent additional weight and side loads from being placed on the damaged tire and thus increase the range that the vehicle can travel.  
         [0012]     Such a remedy is provided by individual wheel station ride height control. This is possible on vehicles such as the LM FTTS due to its 4-corner independent suspension and adjustable ride height capabilities. When the vehicle has a damaged tire or tires the operator would adjust the ride height of the appropriate wheel stations appropriately to achieve a level attitude for the vehicle thus preventing additional destructive loads from being placed on the damaged tire(s). This process may be automated so that one push of a button would adjust each wheel station appropriately.  
         [0013]     In one embodiment, a method for extending the operating range of a deflated run-flat tire on a vehicle, comprises the steps of determining that a tire on the vehicle is deflated, and adjusting one or more of a plurality of adjustable supports. One example, although not limited thereto, is utilizing existing suspension height adjustment to compensate for tilting of the vehicle due to the deflated tire. Such adjustment may be only necessary in one corner (suspension) of the vehicle.  
         [0014]     The step of adjusting may include adjusting one or more of the plurality of adjustable supports by a distance substantially equal to a difference in radius between an inflated run-flat tire and a deflated run-flat tire.  
         [0015]     The vehicle may include a pair of parallel wheels with separate run-flat tires having separate wheels located opposite each other on opposite sides of the vehicle and mounted on respective suspension components attached to a chassis of the vehicle, wherein the plurality of adjustable supports may include a separate adjustable support located to determine a suspension height adjustment between each respective wheel and the chassis, and further wherein the step of adjusting may include adjusting either one or both of the plurality of adjustable supports to compensate for tilting of the vehicle caused by a single deflated tire. The step of adjusting may include shortening an adjustable support corresponding to a tire that is still inflated to compensate for tilting of the vehicle caused by a deflated tire. The step of determining that a tire is deflated may include monitoring air pressure in one or more tires of the vehicle. The step of adjusting may include monitoring vehicle tilt.  
         [0016]     In another embodiment, a system for extending the operating range of a deflated run-flat tire on a vehicle, comprises means for detecting an existing suspension height adjustment of the vehicle, and means for adjusting one or more of a plurality of adjustable supports on the basis of a detected existing suspension height adjustment to compensate for tilting of the vehicle due to the deflated tire.  
         [0017]     The means for adjusting may be adapted to adjust one or more of the plurality of adjustable supports by a distance substantially equal to a difference in rolling radius between an inflated run-flat tire and a deflated run-flat tire.  
         [0018]     The vehicle may include a pair of parallel wheels having separate wheels located opposite each other on opposite sides of the vehicle and mounted on respective suspension components attached to a vehicle chassis, wherein the plurality of adjustable supports may include a separate adjustable support located to determine a suspension height adjustment between each respective wheel and the chassis.  
         [0019]     The vehicle may include a second pair of parallel wheels having separate wheels located opposite each other on opposite sides of the vehicle and mounted on respective suspension components attached to the chassis, said second pair of parallel wheels being longitudinally separated along the vehicle chassis from the first recited pair of parallel wheels, wherein the plurality of adjustable supports may include a separate adjustable support located to determine a suspension height adjustment between the chassis and each respective wheel of the second pair of parallel wheels. The means for adjusting may be adapted to compensate for tilting in a longitudinal direction of the vehicle.  
         [0020]     The system may further comprise means for detecting a deflated run-flat. The means for detecting a deflated tire may include a pressure sensor associated with one or more tires of the vehicle. The means for adjusting may be adapted to use compressed air or pressurized liquid to control the plurality of adjustable supports. The vehicle may, but not necessarily, be a military tactical vehicle.  
         [0021]     In yet another embodiment of the present invention, a vehicle may have a system for extending the operating range of a deflated run-flat tire, comprising means for detecting an existing suspension height adjustment of the vehicle, and means for adjusting one or more of a plurality of adjustable supports on the basis of a detected existing suspension height adjustment to compensate for tilting of the vehicle due to the deflated tire.  
         [0022]     The means for adjusting may be adapted to adjust one or more of the plurality of adjustable supports by a distance substantially equal to a difference in radius between an inflated run-flat tire and a deflated run-flat tire.  
         [0023]     The vehicle may include a pair of parallel wheels having separate wheels located on opposite sides of the vehicle and mounted on respective suspension components attached to a vehicle chassis, wherein the plurality of adjustable supports may include a separate adjustable support located to determine a suspension height adjustment between each respective wheel and the chassis.  
         [0024]     The vehicle may include a second pair of parallel wheels having separate wheels located on opposite sides of the vehicle and mounted on respective suspension components attached to a vehicle chassis, said second pair of parallel wheels being longitudinally separated along the vehicle chassis from the first recited pair of parallel wheels, further wherein the plurality of adjustable supports may include a separate adjustable support located to determine a suspension height adjustment between the chassis and each respective wheel of the second pair of parallel wheels. The means for adjusting may be adapted to compensate for tilting in a longitudinal direction of the vehicle.  
         [0025]     For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a schematic illustration of a vehicle according to an embodiment of the present invention having adjustable supports and run-flat tires;  
         [0027]      FIG. 2  is a cross-sectional schematic illustration of a portion of a run-flat tire;  
         [0028]      FIG. 3  is a schematic illustration of an embodiment according to the present invention showing a system for adjusting or compensating for the tilt associated with a vehicle having a deflated run-flat tire;  
         [0029]      FIG. 4  is a schematic illustration of a vehicle according to an embodiment of the invention having a deflated run-flat tire;  
         [0030]      FIG. 5  is a flow chart of a method according to an embodiment of the present invention for identifying deflated run-flat tires and for adjusting adjustable supports;  
         [0031]      FIG. 6  is a flow chart of a method for adjusting adjustable supports;  
         [0032]      FIG. 7A  is a schematic illustration of a vehicle operating on a deflated run-flat tire with an off-road suspension height;  
         [0033]      FIG. 7B  is a schematic illustration of a vehicle according to an embodiment of the present invention operating on a deflated run-flat tire with an off-road suspension height after adjustment of at least one adjustable support;  
         [0034]      FIG. 8A  is a schematic illustration of a front view of a vehicle operating on a deflated run-flat tire with an on-road suspension height;  
         [0035]      FIG. 8B  is a schematic illustration of a front view of a vehicle according to another embodiment of the present invention operating on a deflated run-flat tire with an on-road suspension height after adjustment of at least one adjustable support; and  
         [0036]      FIG. 9  is a perspective view of a sample independent suspension unit capable of use with various embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]      FIG. 1  illustrates a vehicle according to an embodiment of the present invention. The vehicle  100  is capable of carrying a load  105 . Each wheel  110  of vehicle  100  contacts the ground or terrain  120  with a tire  115  and is supported by an independent suspension  112 . Each tire  115  (shown in its inflated condition in  FIG. 1 ) is typically a run-flat tire. The body, chassis or sprung portion  125  of the vehicle  100  is suspended above each wheel  110  by an adjustable support  130 , illustrated in schematic fashion in  FIG. 1  to work in parallel with the independent suspension  112  and which may include an air spring or a hydraulic strut. The adjustable support  130  provides a variable suspension height for the vehicle body or chassis  125 . Controls  135  for the selective expansion of the adjustable supports  130  may be in the vehicle  100  and operated manually by the operator  140  of the vehicle  100 .  
         [0038]      FIG. 2  contains a cross-sectional view of a portion of a wheel  110 , including a run-flat tire  115  with a run-flat insert  210 . In  FIG. 2 , the run-flat insert  210  is fixed to a rim  215  of the wheel  110  and projects approximately half way between the rim  215  and the tire tread  220 . In other embodiments of the present invention, the run-flat insert  210  may be integral with the run-flat tire  115 . When the run-flat tire  115  is inflated, pressurized air within the tire  115  suspends the wheel rim  215  above the tread  220 . Should the run-flat tire  115  lose air pressure and deflate, the rim  215  falls toward the ground  120  until the outer surface  225  of the run-flat insert  210  rests against the back  230  of the tread  220 . In such a situation, the run-flat insert  210  supports the weight of the vehicle  100  carried by that wheel  110 . Although a deflated run-flat tire incorporating the run-flat tire insert  210  may continue to support the vehicle  100  in rolling mode, the run-flat insert  210  does not offer a permanent solution.  
         [0039]     The vehicle  100  may run on the run-flat insert  210  for only a limited distance without damaging or destroying the tire  115  ( FIG. 1 ) or the run-flat insert  210 . Ordinarily, the sprung body or chassis  125  of the vehicle  100  is level with, that is, parallel to the terrain or ground  120  over which the vehicle  100  moves. However, when the vehicle  100  runs or operates on the run-flat insert  210 , additional weight is transferred from the inflated run-flat tires unto the deflated run-flat tire. The additional weight on the deflated run-flat tire imposes a further load that may accelerate damage to the deflated run-flat tire and to the run-flat insert  210 . The present invention can delay damage incurred by a deflated run-flat tire and the run-flat insert  210  and therewith extend the range of travel of the vehicle  100  running on the deflated run-flat tire and the run-flat insert  210 .  
         [0040]      FIG. 3  contains a schematic illustration of the components of an embodiment according to the present invention. Each wheel  110  enumerated in  FIG. 3  as, front left  302 , front right  304 , rear left  306 , and rear right  308  is provided with an adjustable support  130  ( FIG. 1 ) in the form of an air spring or a hydraulic strut for front left  312 , front right  314 , rear left  316 , and rear right  318  collectively supporting the sprung portion  125  ( FIG. 1 ) over each wheel  110 .  
         [0041]     The pressurizing device  350  may be a compressor supplying a compressed gas such as compressed air, or it may be a pump supplying a pressurized liquid such as pressurized hydraulic fluid, to a storage tank  352  for use in expanding the adjustable supports  312 ,  314 ,  316 ,  318 . Pressure indicators  322 ,  324 ,  326  and  328  are interposed, respectively, between adjustable supports  312 ,  314 ,  316 ,  318  and controller  358 . The storage tank  352  is connected with a front valve  354  and with a rear valve  356 . The front valve  354  selectively provides pressurized fluid to the front left and right air spring/hydraulic struts  312 ,  314 , and the rear valve selectively provides pressurized fluid to the rear left and right air spring/hydraulic struts  316 ,  318 .  
         [0042]     A controller  358  furnishes signals to the front valve  354  and to the rear valve  356 , allowing selective expansion or contraction of the front left  312 , front right  314 , rear left  316 , and rear right  318  air spring/hydraulic strut. Where the adjustable supports  130  are air springs, for example, expansion corresponds to inflation of the air springs and contraction corresponds to deflation of the air springs. The adjustable supports  130  may also be any suitable driveable mechanisms. Lateral and longitudinal tilt sensors  360 ,  362 , respectively, may be linked to either controller  358  or an overall suspension control system  364 .  
         [0043]     As diagrammed in  FIG. 4 , operator assessment or a signal from a central tire inflation system (CTIS) may indicate the presence of a deflated tire  342 . In some circumstances, the tilt of the vehicle  100 , that is, the angle that the sprung portion  125  makes with the terrain  120  or unsprung portion  127  in the longitudinal or rear-to-front direction and in the lateral or right-to-left direction as observed or even automatically sensed, may also indicate the possibility of a deflated or under inflated tire. Longitudinal tilt  405  refers to tilt from back to front and lateral tilt refers to tilt from right to left. A tilt where the rear  425  of the vehicle  100  is lower than the front  430  of the vehicle  100  relative to the ground or terrain  120  is positive and a tilt where the rear  425  of the vehicle  100  is higher than the front  430  of the vehicle  100  relative to the ground or terrain  120  is negative. A tilt where the right side  435  of the vehicle  100  is lower than the left side  440  relative to the ground or terrain  120  is positive and a tilt where the right side  435  of the vehicle  100  is higher than the left side  440  relative to the ground or terrain  120  is negative. Right and left reflect the orientation of the operator  140  ( FIG. 1 ) of the vehicle  100  facing forward.  FIG. 4  illustrates a vehicle  100  with a negative longitudinal tilt  405  and a negative lateral tilt  410  as a result of deflated front left run-flat tire  342 .  
         [0044]      FIG. 5  contains a flow chart of a method  500  according to an embodiment of the invention for compensating for vehicle tilt caused by a deflated or under inflated tire  342  ( FIG. 4 ). In step  510 , a deflated tire  342  is detected. Detection may be the result of observation by the operator  140  ( FIG. 1 ) or a CTIS error message. In step  515 , there is, under certain circumstances, determination of a suspension height adjustment, or off-road status of the vehicle  100 , whether the vehicle  100  ( FIG. 1 ) is adjusted for off-road operation where the sprung body or chassis  125  is at an extended suspension height. The current suspension height is used to determine the proper compensation of the deflated tire. If the sprung body or chassis  125  is not adjusted to the extended height, the adjustable support  312  of the deflated tire  342  is expanded (step  520 ). If the sprung body or chassis  125  is adjusted to the extended suspension height, the adjustable supports of the inflated tires are contracted (step  525 ).  
         [0045]     To determine whether the tilt of the vehicle  100  has been eliminated and the vehicle  100  is level with the terrain  120 , adjustment of the adjustable supports  312 ,  314  continues until the tilt of the sprung body or chassis  125  substantially matches the tilt of the terrain  120 . An operator  140  may observe the tilt of the vehicle  100 , either with or without reference to tilt sensors  360 ,  362 , and discontinue adjustment of the adjustable supports  312 ,  314  when the sprung body or chassis  125  is level with the ground  120 .  
         [0046]     Still another approach is to use the difference in rolling radius between an inflated run-flat tire  115  and a deflated run-flat tire  342  as provided by the manufacturer of the run-flat tire to determine the adjustment to the appropriate adjustable supports  312 ,  314 ,  316 ,  318  necessary to level the vehicle  100  with the terrain  120 .  
         [0047]      FIG. 6  contains a flow chart of an example of a method  600 , where the deflated run-flat tire is detected by the operator  140  ( FIG. 1 ) or by the CTIS. Once the identity of the deflated run-flat tire resting on its run-flat insert  210  ( FIG. 2 ) has been determined either by lateral or longitudinal tilt or other type of sensing such as by a decrease in tire air pressure or other operator assessment, the orientation of an appropriate corner of the sprung body or chassis  125  may be adjusted.  
         [0048]     In order to provide an illustrative example of, for instance, where run-flat tire  342  (used as an example) is deflated, reference is now made, but not limited to,  FIGS. 4, 6 ,  7 A,  7 B,  8 A and  8 B. Therefore, in the flow chart shown in  FIG. 6 , decision boxes  608  and  616  provide a direct flow through to decision box  624 , which is the decision box used with the example of deflated run-flat tire  342 . If the longitudinal tilt  405  is less than zero, that is, if the front  430  of vehicle  100  is lower than the rear  425  of vehicle  100 , and if the lateral tilt  410  is less than zero (see  624 ), that is, if the left side  440  of the vehicle  100  is lower than the right side  435  of the vehicle  100 , then, for example, the front left run-flat tire  342  has been deflated. If the vehicle suspension is in on-road condition, that is, if the suspension has not been elevated and still corresponds to the on-road level, then, to even the level of the sprung body or chassis  125 , the specific adjustable support  312  over the front deflated left run-flat tire  342  is extended (see  628 ). If the vehicle suspension is in an off-road condition where the suspension has been expanded to raise the sprung body or chassis  125 , then, the front right  314 , rear right  318 , and rear left  316  adjustable supports are contracted (see  630 ) to bring the sprung body or chassis  125  to a position even or level with the ground  120 .  
         [0049]     It is not necessary to provide separately for both off-road and on-road conditions, since the present invention operates properly without such special arrangements. However, if desired, such a feature may be provided as discussed below.  
         [0050]     An example of an embodiment of the present invention where the front left run-flat tire  342  is deflated is illustrated in  FIG. 7A  and  FIG. 7B  for an off-road condition and in  FIG. 8A  and  FIG. 8B  for an on-road condition. The suspension components are very generally represented in  FIGS. 7A, 7B ,  8 A,  8 B for purposes illustrating the functionality of adjusting the suspension for a deflated tire. Details of suspension components are described in respect to  FIG. 9  and described in more detail below. In  FIGS. 7A and 7B , the vehicle  100  is shown in the off-road condition, where the front left run-flat tire  342  is deflated and is running on insert  210  and where the vehicle  100  has assumed a tilt toward the front left run-flat tire  342 . Since the vehicle suspension is raised for off-road travel, the adjustable supports, including the front left  312 , have substantially no additional capacity for extension. Since the vehicle suspension is adjusted for off-road, the level of the sprung body or chassis  125  is evened with the terrain, as shown in  FIG. 7B , by having the adjustable supports  314  for the inflated front right tire  344  ( FIG. 3 ), as well as supports  316 ,  318  for the rear left tire  346 , and rear right tire  348 , respectively ( FIG. 3 ) contracted as shown in  FIG. 7B .  
         [0051]      FIGS. 8A and 8B  illustrate the vehicle  100  adjusted for on-road operation and the adjustable supports are contracted. As in  FIG. 7A  and  FIG. 7B , in  FIGS. 8A and 8B  the front left run-flat tire  342  is deflated and is supported on its run-flat insert  210 . To make the sprung portion  125  even with the terrain, the adjustable support  312  for the deflated front left run-flat tire  342  is extended appropriately while the other adjustable supports remain substantially in the contracted positions as shown in  FIG. 8B .  
         [0052]     Referring back to  FIGS. 3, 4  and  6 , in the event, for example, that the rear right run-flat tire  348  is deflated, the longitudinal tilt  405  is greater than zero and the lateral tilt  410  is greater than zero (see  616 ), that is, the rear  425  is lower than the front  430  and the right side  435  is lower that the left side  440 . If the vehicle  100  is adjusted for on-road operation, leveling of the sprung body or chassis  125  is accomplished by extending the rear right adjustable support  318  (see  620 ). If the vehicle suspension is adjusted for off-road operation, evening the level of the sprung body or chassis  125  involves decreasing the heights of the front right  312 , front left  314 , and rear left  316  adjustable supports associated with the front right  304 , front left  302 , and rear left  306  wheels (see  622 ).  
         [0053]     If, for example, the longitudinal tilt  405  is less than zero, that is, if the front  430  is lower than the rear  425 , and the lateral tilt  410  is greater than zero (see  632 ), that is, if the right  435  is lower than the left  440 , then the front right run-flat tire  344  is deflated. If the vehicle suspension is adjusted for on-road operation, leveling of the sprung body or chassis  125  involves extending the front right adjustable support  314  (see  636 ). If the vehicle suspension is adjusted for off-road operation, then leveling the sprung body or chassis  125  involves contracting the front left  312 , rear left  316 , and rear right  318  adjustable supports (see  638 ).  
         [0054]     If, for example, the longitudinal tilt  405  is greater than zero, that is, if the rear  425  is lower than the front  430 , and if the lateral tilt  410  is less than zero (see  608 ), that is, if the left side  440  is lower than the right side  435 , the rear left run-flat tire  346  is deflated. Leveling of the sprung body or chassis  125  involves extending the rear left adjustable support  316  (see  612 ) for a vehicle suspension adjusted for on-road operation. If the vehicle suspension is adjusted for off-road operation, then leveling involves contracting the front left  312 , front right  314 , and rear right  318  adjustable supports (see  614 ).  
         [0055]     The following examples set forth other run-flat tire deflated conditions and are described without the use of additional flow charts but with reference to, but not limited to,  FIGS. 3 and 4 . For example, deflation of two adjacent run-flat tires is identifiable by an absence of either longitudinal tilt  405  or lateral tilt  410 , but not both. If the longitudinal tilt  405  is greater than zero, and the lateral tilt  410  is substantially equal to zero, then the rear left  346  and the rear right  348  run-flat tires are deflated. If the vehicle suspension is adjusted for on-road operation, extension of the rear left  316  and the rear right  318  adjustable supports levels the sprung portion  125  with the ground  120  or the unsprung portion  127 . If the vehicle suspension is adjusted for off-road operation, leveling of the sprung portion  125  is accomplished by contracting the front right  314  and front left  312  adjustable supports.  
         [0056]     If, for example, the longitudinal tilt  405  is less than zero, that is, if the front  430  is lower than the rear  425 , and if the lateral tilt is substantially zero, the front left  342  and front right  344  run-flat tires are deflated. If the vehicle suspension is adjusted for on-road operation, the sprung body or chassis  125  is restored to be level with the ground  120  by extension of the front left  312  and front right  314  adjustable supports. If the vehicle suspension is adjusted for off-road operation, the sprung body or chassis  125  is made level with the ground  120  by contraction of the rear right  318  and rear left  316  adjustable supports.  
         [0057]     If, for example, the longitudinal tilt  405  is substantially zero and the lateral tilt is greater than zero, that is, if the left side  440  is higher than the right side  435 , then the rear right  348  and front right  344  run-flat tires are deflated. If the vehicle suspension is adjusted for on-road operation, the sprung body or chassis  125  is made level with the ground  120  by extension of the front right  314  and rear right  318  adjustable supports. If the vehicle suspension is adjusted for off-road operation, the sprung body or chassis  125  is made level with the ground  120  by contraction of the rear left  316  and front left  312  adjustable supports.  
         [0058]     In addition, it should be realized that the present invention is also applicable, for example, in situations where three run flat tires are deflated or even where two run-flat tires diagonally opposed from each other are deflated. Upon identification of such conditions, leveling of the spring body or chassis  125  is accomplished in the following manner. In the on-road operation, the sprung body or chassis  125  is restored to level with the ground  120  by extension of the adjustable supports associated with the deflated run flat tires. In the off-road operation, the sprung body or chassis  125  is restored to level with the ground  120  by contraction of the adjustable support associated with the inflated run-flat tires.  
         [0059]     If the longitudinal tilt  405  is substantially zero and the lateral tilt is less than zero, that is, if the left side  440  is lower than the right side  435 , then the rear left  346  and front left  342  run-flat tires are deflated. If the vehicle suspension is adjusted for on-road operation, the sprung body or chassis  125  is made level with the ground  120  by extension of the rear left  316  and front left  312  adjustable supports. If the vehicle suspension is adjusted for off-road operation, the sprung body or chassis  125  is made level with the ground  120  by contraction of the rear right  318  and front right  314  adjustable supports.  
         [0060]      FIG. 9  shows a perspective view of a sample independent suspension unit  700  suitable for use with the various embodiments of the present invention. Generally included are a wheel hub  702 , an upper suspension arm  706 , a lower suspension arm  708 , a pair of shock absorbers  710  and an adjustable compressed air bag type of device, such as an air spring  712 . Upper and lower suspension arms  706 ,  708 , respectively, are adapted to maintain a vertical orientation for wheel hub  702  and a wheel mounted thereon while the wheel hub is allowed to move up and down in response to various conditions. Shock absorbers  710  provide support to lower suspension arm  708  from chassis connection points (not shown) to provide dampening of suspension movement. Air spring  712  is adapted for connection to the chassis at one end  704 . Air spring  712  is also adapted for connection to lower suspension arm  708  through a connecting member  718 . In this manner, inflation of air spring  712  causes the lowering of wheel hub  702  with respect to the chassis to thereby provide a higher suspension height for a vehicle.  
         [0061]     Although the invention has been described with respect to various embodiments, it should be realized that this invention is also capable of a wide variety of further and other embodiments within the spirit and the scope of the appended claims. For example, use of this system may be applicable to any vehicle having a real time independent adjustable suspension system and not limited to vehicles with on-road/off-road capability.