Abstract:
A method for integrating tire identification data into a vehicle information system comprises the steps: mounting a tire to a production line vehicle chassis, the tire having tire data storage for storing tire identification data; connecting the tire stored data to a vehicle electronic control unit (ECU) having ECU data storage; reading tire identification data from the stored tire data into the ECU stored data; and uploading the tire identification data from the ECU stored data to an OEM database. The method may optionally include incorporating a tire pressure monitoring system into the tire; and including tire pressure monitoring system identification data in the tire identification data. The vehicle identification data may be incorporated into the ECU stored data and uploaded with the tire identification information to an OEM database at a preferred point in the vehicle assembly line sequence that coincides with the execution of an end-of-line diagnostic test on the vehicle.

Description:
FIELD OF THE INVENTION 
   The invention relates generally to a method for integrating tire data into the information system of a vehicle and, more specifically, within tire systems comprising a tire pressure monitoring system. 
   BACKGROUND OF THE INVENTION 
   Safe, efficient and economical operation of a vehicle depends, to a significant degree, on maintaining the correct air pressure in the tires of the vehicle. Failure to promptly correct faulty air pressure may result in excessive tire wear, blowouts, poor gasoline mileage, and steering difficulties. Hence, it is generally desirable to provide a low pressure warning system within the vehicle to alert the driver to the loss of air in a pneumatic tire. The means for warning a driver may comprise a light on the dashboard or an audible alarm. 
   To this end, a number of electronic devices and systems are known for monitoring the pressure of pneumatic tires, and providing the operator of the vehicle with either an indication of the current tire pressure or alerting the operator when the pressure has dropped below a predetermined level. It is known, for example, to monitor tire pressure with a transponder that is capable of receiving and transmitting radio frequency signals and impressing variable information (data) in a suitable format upon the transmitted signal indicative of one or more measured conditions such as pressure and temperature. A “tag”, as used herein, refers either to a transponder having transmitting and receiving capability or to a device that has only transmitting capability. Generally, a tire pressure monitoring system (TPMS) indicates an overall system comprising tags within the tires and a receiver disposed within the vehicle. 
   It is known to mount a tag and associated condition sensor within each tire of a vehicle and collect information from each transponder with a receiver mounted to the vehicle. The tag may be mounted to a valve stem or attached to an inner liner of the tire. Data received from the tag by the receiver is transmitted to a display unit for alerting the vehicle operator on the status of each tire. Electronic data processing circuitry for receiving and interpreting sensor data for appropriate display is typically part of the TPMS. A common approach within the industry is to implement a transponder as an integrated circuit chip on a printed circuit board within the tag. An application specific integrated circuit (ASIC) is typically employed and may include memory for storing measurement or transponder identification data. Data from the transponder to a reader is typically facilitated by radio frequency (RF) signal transmission. 
   It is common within the industry for the tag and transponder to be manufactured by an electronics entity and supplied to a tire manufacturer for incorporation into a tire. The tire, having the transponder and tire tag operatively coupled thereto, is then transferred to an original equipment manufacturer (OEM) and mounted to a production line vehicle. The tires for any given vehicle are generally mounted to the chassis frame at some point in the assembly line and proceed with the chassis down the assembly line to an end point. 
   It is further a standard practice in the vehicle manufacturing processes used by the industry to incorporate a vehicle electronic control unit (ECU) within the vehicle to control and monitor vehicular electronic systems. The ECU is incorporated within the vehicle during the assembly process and interconnected to electrical components and systems upon their installation. At or near the end point of the assembly process, the vehicle electronic control unit (ECU) conducts a system diagnostic test, testing components and systems for operational performance. Typically, data from the diagnostic test is then uploaded to an OEM data base and retained for future reference should the need arise. 
   The identity of the transponder and tag is designated by the manufacturer of such components by an identification code. Likewise, the tire manufacturer maintains an information system database that identifies each tire it produces by an identification code. Similarly, the OEM utilizes a vehicle-specific identification code, commonly referred to as a vehicle identification number (VIN). The VIN is maintained in an information system database and provides the basis for tracking a given vehicle throughout its operational life. The vehicle electronic control unit (ECU) that electronically controls the operation of sundry systems within the vehicle may further be encode with the VIN identification number. The OEM may further employ a part number for identifying the specific tire that is mounted to any given vehicle. The part number is typically used for inventory control and re-ordering procedures. 
   It is generally desirable for an OEM to maintain tire identification information so as to enable the OEM cross-reference the particular tires with the assembly line vehicles to which the tires are mounted. Such tire identification data may be manually inputted into a database but such a procedure is inefficient and labor intensive, whereby undesirably adding to the manufacturing cost. Alternatively, the manufacturer (OEM) may employ readers along the assembly line to read tire identification off the tires as the tires pass the reader. Employing such a dedicated system of tire readers along the assembly line for the sole purpose of reading tire identification codes is, however, expensive and inefficient. 
   The aforementioned division of responsibility between the transponder/tag, tire, and vehicle manufacturers generally works well with each party operating within respective spheres of expertise and maintaining respective databases identifying the products produced by each manufacturer. Heretofore, however, there has been no systematic method or process for conveniently integrating data from the transponder/tag, tire, and vehicle manufactures into a single readily accessible database. Specifically, there has been no systematic method or process for conveniently and readily associating the transponder/tag, tire, and vehicular identification codes and operational parameters into a single database for future reference by those parties having a need to cross-reference such data. Those parties having such a need can include the manufacturer of the transponder/tag, tire, or vehicle, or down stream dealers responsible for the sale and maintenance of the vehicle. 
   There is, therefore, a long felt need for a system to gather and maintain positive tire identification data without the need for external dedicated antenna and reader systems along the assembly line. Further, a needs exist for a method and procedure for effectively and efficiently gathering and storing in a single database transponder/tag, tire, and vehicle identification data and related information so as to be readily accessible by interested parties. Vehicle dealers would thereby be in a position to conveniently access and retrieve tire information from the database for determining, by way of example, whether a given tire has been changed or replaced. Such a capability, if available, would be desirable in affording the transponder, tire, and vehicle manufacturers, as well as the vehicle dealer selling and servicing the vehicle, with means for tracking the history of the various components comprising the TPMS. In the event of a system or component failure, specific information would thus be available to determine the identity of the various components that were originally combined to create the TPMS. Moreover, the replacement or substitution of all or portions of the TPMS could be monitored throughout the life of the vehicle in order to aid in failure analysis in the event of system malfunction or damage. 
   SUMMARY OF THE INVENTION 
   The present invention provides a method for integrating tire data into the information system of a vehicle. According to one aspect of the invention, the method comprises the steps of mounting a tire to a production line vehicle chassis, the tire having tire data storage means for storing tire identification data; connecting the tire data storage means to a vehicle electronic control unit (ECU) having ECU data storage means; reading tire identification data from the tire data storage means into the ECU data storage means; and uploading the tire identification data from the ECU data storage means to an OEM database. According to another aspect of the invention, the method includes incorporating a tire pressure monitoring system into the tire; and including tire pressure monitoring system identification data in the tire identification data. Pursuant to a further aspect of the invention, tire pressure monitoring system operational parameters are incorporated within the tire identification data. According to yet a further aspect of the inventive method, vehicle identification data is incorporated into the ECU data storage means and uploaded to an OEM database. A further aspect of the invention reads tire identification data from the tire data storage means into the ECU data storage means substantially coincidental with the running of a diagnostic test by the ECU substantially at the conclusion of vehicular assembly. 
   Definitions 
   “Axial” and “axially” means the lines or directions that are parallel to the axis of rotation of the tire. 
   “Bead” or “bead core” generally means that part of the tire comprising an annular tensile member of radially inner beads that are associated with holding the tire to the rim; the beads being wrapped by ply cords and shaped, with or without other reinforcement elements. 
   Circumferential” most often means circular lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial directs; it can also refer to the direction of the sets of adjacent circular curves whose radii define the axial curvature of the tread, as viewed in cross section. 
   “Inner” means toward the inside of the tire and “outer” means toward its exterior. 
   “Lateral” means in a direction parallel to the axial direction. 
   “Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire. 
   “Shoulder” means the upper portion of sidewall just below the tread edge. 
   “Sidewall” means that portion of tire between the tread and the bead. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a representative tire, antenna, and transponder apparatus with portions of the tire removed for the purpose of illustration. 
       FIG. 2  is a sectional schematic of a tire mounted to a rim and illustrating alternative locations in which to mount the subject annular apparatus. 
       FIG. 3  is an enlarged perspective view of a tire portion having a transponder and antenna assembly positioned against a tire sidewall surface. 
       FIG. 4  is a sectional schematic view of a tire and wheel assembly mounted to a vehicle frame. 
       FIG. 5  is an enlarged perspective view of a representative antenna projecting through a transponder module. 
       FIG. 6  is an enlarged perspective view of a portion of a representative annular assembly. 
       FIG. 7  is a front perspective view of a representative transponder module. 
       FIG. 8  is an exploded perspective view thereof. 
       FIG. 9  is a top plan view thereof. 
       FIG. 10  is a longitudinal section view through the transponder module of  FIG. 9  taken along the line  10 — 10 . 
       FIG. 11  is a transverse section view through the transponder module of  FIG. 9  taken along the line  11 — 11 . 
       FIG. 12  is a perspective view of the module circuit board. 
       FIG. 13  is a perspective view of the receiver module. 
       FIG. 14  is a block diagram of the car transceiver and tire monitoring system. 
       FIG. 15  is a simplified block diagram of a TPMS installed on a vehicle. 
       FIG. 16  is a schematic illustration of a multiplexed TPMS installed on a vehicle. 
       FIG. 17  is a block diagram illustrating the subject tire tag initialization procedure. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As used herein, a “transponder” is an electronic apparatus (device) capable of monitoring a condition such as air pressure within a pneumatic tire, and then transmitting that information to an external device. The external device can be either an RF (radio frequency) reader/interrogator or, simply an RF receiver. A simple receiver can be used when the transponder is “active”, and has its own power source. A reader/interrogator would be used when the transponder is “passive” and is powered by an RF signal from the reader/interrogator. In either case, in conjunction with the external device, the transponder forms a component of an overall tire-condition monitoring/warning system. A toroidal body composed of a material of high electro-magnetic permeability is coupled to the transponder by a winding. In conventional systems, the antenna is coupled to the toroidal body by means of a primary winding and the transponder is coupled to the toroidal body by means of a secondary winding. As explained below, the primary winding is eliminated in accordance with the practice of the subject invention. The “secondary” winding that couples a transponder to the toroidal body hence is referred to herein as merely the “winding”. For the purpose of the subject disclosure and the invention, the annular system is not transponder specific. That is, a wide range of commonly available transponders, sensors, and associated electronics may be packaged and utilized with the subject invention. 
   As used herein, a “toroid” is a body formed from material having a high elector-magnetic permeability by a continuous curved surface and includes a central through bore. The toroidal body may be cylindrical, oblong, symmetrical, or asymmetrical without departing from the invention herein set forth. As used herein, a “toroidal body” thus includes a transformer having one or more windings. 
   In order to send or receive RF signals, a transponder must have an antenna. The antenna is annular in configuration in the subject invention and may either be incorporated into the tire during manufacture or affixed to the tire by way of a post manufacture procedure. As used herein, an “annular antenna” may be circular, oblong, symmetrical, or asymmetrical without departing from the subject inventive principles. However, the preferred configuration of the antenna is circular and sized to overlap the tire sidewall region to which it attaches. The antenna may comprise a single wire or a plurality of strands. Various commercially available transponders, sensors, and other electrical devices deployed in combination with an annular antenna formed from conventional conductive materials are suitable for use in conformance with the principles of the subject invention. 
   Acceptable materials for the antenna wire include steel, aluminum, copper or other electrically conducting wire. As disclosed in this patent document, the wire diameter is not generally considered critical for operation as an antenna for a transponder. For durability, stranded steel wire consisting of multiple strands of fine wire is preferred. Other wire options available include ribbon cable, flexible circuits, conductive film, conductive rubber, etc. 
   Referring initially to  FIG. 1 , a preferred embodiment  10  of a TPMS is shown deployed within a tire  12 . The tire  12  is formed from conventional materials such as rubber or rubber composites by conventional means and may comprise a radial ply or bias ply configuration. A typical tire  12  is configured having a tread  14 , a shoulder  16 , an annular sidewall  18 , and a terminal bead  20 . An inner liner  22  is formed and defines a tire cavity  24 . The tire  12  is intended for mounted location upon an annular rim  26  having a peripheral rim flange and an outer rim flange surface  30 . Rim  26  is conventionally configured and composed of a suitably strong metal such as steel. 
   An annular antenna  32  is provided and, in the preferred embodiment, embodies a sinusoidal configuration. Antenna  32  may be alternatively configured into alternative patterns or comprise a straight wire(s) if desired and may be filament wire, or cord or stranded wire. Acceptable materials for the wire include steel, aluminum, copper or other electrically conducting wire. As mentioned previously, the wire diameter is not generally considered critical for operation as an antenna and multiple strands of fine wire is preferred. The curvilinear form of antenna  32  provides flexibility and minimizes the risk of breakage during manufacture and use explained below. 
   With continued reference to  FIG. 1 , a transponder module  34  of the general type described above is provided and may include means for sensing tire parameters such as pressure and temperature. Included as part of the apparatus  10  is a carrier strip of material  36  formed into the annular configuration shown. Carrier strip  36  is formed of electrically insulating, preferably semi-rigid elastomeric material common to industry such as rubber or plastic. The strip  36  is formed to substantially encapsulate the antenna wire(s)  32  and at least a portion of the transponder module  34  in the manner described below. In the post manufacturing state, therefore, the apparatus  10  comprising antenna  32 , transponder module  34 , and carrier strip  36 , in a unitary, generally circular, semi-rigid assembly that is readily transportable and handled for attachment to tire  12 . The diameter of the apparatus assembly  10  is a function of the size of the tire  12  and the preferred attachment location thereon. 
     FIG. 2  illustrates a preferred location for annular apparatus  10  on a tire. The tire  12  is mounted to a rim  26  in conventional fashion. The bead  20  of tire  12  is disposed within the rim  26  against flange  28 . Upper surface  30  of the flange  28  is located above a lower edge of the tire bead  20 . As will be appreciated, the flange  28  shields the lower portion of the tire  12  comprising bead  20  and defines an “RF INTERFERENCE” region  38  of the tire. A region  40  of tire  12  above region  38  at the sidewall  18  is further defined as a “HIGH STRAIN AMPLITUDE” region. As sidewall  18  flexes during operation of the tire on a vehicle, region  40  experiences a high level of strain. The region  42  located at the tread portion of the tire is referred to herein for explanatory purposes as a “COMPRESSIVE STRAIN” region. It is at region  42  that the tire  12  experiences a high level of compressive strain as the tire is operatively utilized. 
   In combined reference to  FIGS. 1 and 2 , the apparatus  10  is affixed to liner  22  of the tire  12  either during manufacture of the tire or, as preferable, in a post-manufacture assembly operation. Attachment may be by means of an adhesive or the apparatus may be embedded into the tire itself during manufacture. Adhesives commonly utilized in the industry for tire patch and repair may be employed. The location on the tire to which apparatus  10  is attached pursuant to the instant invention is region  44  in  FIG. 2 , located between the RF INTERFERENCE region  38  and the HIGH STRAIN AMPLITUDE region  40 . It will be appreciated that region  38  would be equitable from a mechanical perspective since tire region  38  is relatively rigid, protected by rim flange  28 , and, experiences a relatively low strain level during operation of the tire. From an electrical perspective, however, region  38  of the tire  12 , shielded by rim flange  28 , is ill suited as a location for the transponder  34 . 
   Location of the apparatus  10  within region  40  of the tire sidewall  18  is an option. Such a location would avoid the RF Interference caused by the rim. However, the tire sidewall  18  experiences high levels of strain during operation of the tire. Consequent damage to or breakage of components affixed to the sidewall may occur. Similarly, location of the apparatus  10  at the tread region  42  of tire  12  would avoid RF Interference from the rim but the tread region experiences high compression strain during operation of the tire. Location of tire monitoring system devices in such a location would be therefore be undesirable from a mechanical perspective. 
   Consequently, apparatus  10  is preferably located within region  44  of the tire  12 . Region  44  is generally an annular region located substantially between 10 to 30 millimeters above the upper surface  30  of the rim flange  28  when tire  12  is mounted to rim  26 . Within region  44 , the apparatus is free from RF Interference from the flange  28  of rim  26 . Region  44  is further a relatively low strain amplitude region of the tire  12 . Thus, region  44  of the tire  12  represents an optimal location for apparatus  10  that balances the need for minimal RF Interference from the rim while mechanically protecting the apparatus  10  from damage due to strain forces introduced into the tire during its operation. 
     FIG. 3  illustrates an alternative embodiment of the subject apparatus  10  in which the carrier strip  36  is eliminated and the antenna  32  and transponder  34  are embedded directly within the tire  12  during its manufacture. The location of the antenna  32 , again, is within region  44  described as optimal in the preceding paragraph; that is, approximately 10–30 millimeters above the rim flange surface  30  when tire  12  is mounted to rim  26 . Attaching the apparatus  10  into tire  12  during its manufacture is possible pursuant to the invention but is not preferred since such a procedure would necessarily expose the transponder  34  and antenna to potentially damaging forces as the tire is formed. Also, implanting an exposed annular antenna  32  and transducer  34  makes replacement and repair of the assembly in the event of damage or breakage problematic. Consequently, it is preferable to attach the apparatus  10  to the tire  12  in a post manufacture process by adhesives or the like. The advantages of post manufacture assembly is that the apparatus  10  is spared the stress of the tire manufacturing process and the apparatus  10  may readily be removed and replaced in the event of breakage. Moreover, the unitary apparatus  10  shown in  FIG. 1  may readily be retrofitted by adhesive to pre-manufactured or used tires. Finally, the annular apparatus is a unitary assembly and may be conveniently inventoried in a range of diametric sizes so as to fit various sized pre-manufactured tires. 
     FIG. 4  shows the transponder  34  located at its preferred location on a tire  14  and exposed to the tire cavity  24 . The transponder may include pressure and temperature sensors for monitoring the status of the cavity  24  and communicate such information to a remote transceiver  48  mounted to the vehicle frame  46 . The transceiver  48  is positioned opposite the antenna of the apparatus  10  and is in continuous communication therewith throughout the 360 degrees rotation of the tire  14 . Transceiver  48  is of a type commercially available in the industry and is electrically connected by lead  50  to conventional logic, processing and display electronics of the vehicle. As described previously, the position of the transponder module  34  is above the rim flange  28  so that RF communication between the transponder and the transceiver  48  is not impaired. 
   With collective reference to  FIGS. 5–12 , the configuration of the annular apparatus  10  will be explained in greater detail. The transponder module generally comprises a base housing  52  formed of rubber or plastic material by conventional means. The housing  52  includes opposite sidewalls  54 ,  56  joining along a radiused bottom surface  55  to opposite vertical end walls  58 ,  60 . The walls  54 ,  55 ,  56 ,  58 , and  60  define a central compartment  62 . A through bore  64  extends through lower portion of the end walls  58 ,  60  in communication with the compartment  62 . 
   The housing  52  further includes a cap member  68  likewise formed of conventional rubber or plastic material by conventional means such as injection molding. The cap member  68  includes an upper protrusion or “snout”  70  comprising vertical sidewalls  72  terminating at a horizontal upper surface  74 . A sensor port or aperture  76  is positioned at the middle of surface  74  and extends therethrough. A flange  78  peripherally defines a lower boundary of cap  68  and provides a horizontal ledge surface  80  that merges at a right angle with the vertical sidewalls  72 . The flange  78  is dimensioned to rest upon the upper end of the module base housing  52  as will be appreciated. The horizontal ledge surface  80  of cap  68  is disposed between the flange  78  and the vertical sidewalls  72 . Upper sidewall portions  81  are provided that taper inwardly toward upper surface  74 . The tapered profile of the cap  68  facilitates convenient and reliable manufacture of the apparatus  10 . 
   In the illustrated embodiment, the transponder module  34  further includes a toroidal body (toroid)  82  composed of a material, such as a ferrite, having a high electro-magnetic permeability. The body  82  generally comprises a cylinder having an elliptical cross-sectional configuration. The elliptical sectional configuration of body  82  serves to reduce its vertical dimension and allows for a more compact packaging of the body  82  within a transponder module. The body  82  includes a winding  84 , as shown, terminated to conductor leads  86 . A central through bore  88  projects through the body  82  in an axial or longitudinal direction. 
   A protective sleeve member  90  is further provided sized for receipt and residence with the bore  88  of body  82 . The sleeve  90  comprises generally an elongate cylinder having an elliptical cross-section. The sleeve  90  further includes a circumferential sidewall  92  and an axial or longitudinal through bore  94 . Bore  94  is offset relative to the longitudinal axis of the sleeve  90  so as to create a wall  95  of increased thickness at an outward side of the sleeve  90 . An outwardly open longitudinal channel  96  is formed within the wall  95  as shown. The sleeve  90  is closely received within bore  88  of body  82  and winding  84  is received within the channel  96  of sleeve  90 . 
   With continued reference to  FIGS. 5–12 , a circuit board  98  mounts within the central compartment  62  of the transponder base housing  52 . Circuit board  98  is typically configured to comprise an electronic package  100  mounted to an upper surface  102  and may include an electronic package  106  mounted to an underside  104 . The packages  100 ,  106  are commonly referred to as an “application specific integrated circuit” or ASIC. An ASIC includes memory wherein identification data identifying the components of the TPMS may be entered, stored, and retrieved. The electronic packages  100 ,  106  are generically depicted in  FIGS. 5–12  and include the transponder sensors, logic, memory, and RF transmitting systems necessary to perform tire cavity monitoring activity. The subject invention method is not transponder design specific and any one of multiple conventional transponder systems may be utilized and mounted to one or both surfaces  100 ,  104  of circuit board  98 . The board  98  further includes lead receiving channels  108  fabricated within a board side. 
   Assembly of the transponder module proceeds generally as follows. The sleeve  90  is inserted within the through bore  88  of the toroidal body  82  which is then inserted into the chamber  62  of the housing base  52 . Situated within chamber  62 , the through bore  94  of sleeve  90  and the bore  99  of body  82  co-axially align with housing through bore  64 . The winding  84  of body  82  is received within channel  96  of the sleeve  90  and leads  86  are routed upward. The number of turns in winding  84  is designed to impedance match the transponder electronics in a conventional manner. The board  98  mounts horizontally in the preferred embodiment within the housing  52  above the sleeve  90  and the toroidal body  82  through passage. Leads  86  from the winding  84  are routed into the channels  108  and electrically connected to the electronics  100 ,  106  on circuit board  98 . The peripheral flange  78  of the cap member  68  is thereafter positioned upon the upper surface  66  of the housing  52  and the interface is sealed by application of a suitable adhesive. 
   In the assembled condition, the transponder module  34  is as shown in  FIG. 7 . The transponder module housing, internal assembly, and component orientation may be varied if desired in the practice of the invention. The transponder module  34  thus comprises a sealed self contained unit that includes circuit board and transponder electronics for monitoring parameters of a tire cavity such as pressure and temperature. The electronics of the transponder module  34  may further include tire identification information. The toroidal body  82  is electro-magnetically and mechanically coupled to the transponder package  24  via winding  84 . Alternatively, the body  82  may be eliminated and the antenna  32  electrically coupled directly to the transponder. The resultant annular assembly would likewise be positioned in the optimum location described above in a tire. A further alternative would be to couple the antenna  32  to the transponder through a transformer of conventional configuration having primary and secondary windings. 
   The antenna  32  is routed through the transponder module  34  as seen best from  FIG. 5  and comprises a continuous loop. The antenna  32  in the preferred embodiment is formed into a sinusoidal configuration, the sinusoidal shape serving to provide antenna elongation capacity with which to counter strain forces in the tire from its operation. The antenna  32  projects through bore  94  of sleeve  90 , the bore  88  of body  82 , and the through bore  64  of housing  52  in non-contacting manner. The antenna  32  is thus mechanically decoupled from the transponder module  34 . It will be noted that the toroidal body  82  functions as a transformer in which the primary winding is eliminated. The antenna loop  32  is passed directly through the through bore  88  of the toroid  82  and couples magnetically with the body absent a primary winding. Electrical coupling occurs between the loop  32  and the toroidal body  82 , and therefore into the winding  84  because the current induced in the loop antenna  32  from the transceiver  48  magnetic field creates a magnetic near the loop. The magnetic field is induced directly into the toroidal body  82  that closely surrounds the antenna loop wire(s)  32 . 
   Such a coupling, designated herein as Direct Magnetic Coupling (DMC), affords several distinct advantages. The DMC approach allows the antenna loop to pass through the transponder package without a mechanical connection and therefore eliminates the problems with making and maintaining a connection between the loop wire and the transponder package discussed previously. The winding  84  turn ratio may be varied to accommodate optimum impedance matching. Secondly, the DMC technique provides a high energy coupling. Furthermore, the process of attaching the antenna loop to a transponder is simplified rendering the remote coupling between wire bundles or cables and transponders substantially less difficult. Moreover, the magnetic coupling between annular antenna and transponder using the DMC technique is maintained in a continuous 360 degree read and dead zones in the interrogation area are avoided. 
   As discussed previously, the assembly of  FIG. 5  may be embedded into a tire during its manufacture, resulting in the tire assembly shown in  FIG. 3 , although it is not preferable to do so. Incorporation of the annular apparatus during tire build imposes substantial strain into the tire monitoring components and may result in component breakage. In a post cure state, removal of an annular assembly or any component therein may be difficult or impossible. Consequently, it is preferred that the subject annular assembly be affixed to a tire as a post tire build operation. 
   To do so, the antenna  32  and transponder module sub-assembly are first embedded within a rigid or semi-rigid carrier strip  36  shown in  FIGS. 1 and 6 . The strip  36  is formed from a non-conductive encapsulant material such as rubber or plastic and an annular assembly results that is unitary and readily transported, stored, and handled. Creation of a unitary combination of antenna, transponder, and carrier strip facilitates ease of incorporation of the annular assembly into a tire in a post build procedure. The assembly is positioned against the tire liner  22  at a location within the optimum region  44  discussed previously. The strip  36  is adhered to the tire by application of commonly available adhesives. Should the antenna transponder module break in transit or malfunction, the assembly  10  may be removed and replaced without damaging the tire. Moreover, the encapsulant material further serves to maintain the antenna and the toroidal body in their intended mutual orientation. 
   In order to facilitate the ready incorporation of the transponder module  34  into the carrier strip  36 , the housing of the transponder  34  comprising cap  68  and base housing  52  are of a unique stepped and tapered configuration. The cap comprises the tapered snout  70  at an upper end defined by inward tapering surfaces  81 . The cap  68  steps outward at the lower peripheral edge flange  78 . As best viewed from  FIGS. 7 and 11 , the housing snout  70  is received within a cavity  112  within a mold block  110 . The tapered profile renders the transponder housing self registering and centers the housing within cavity  112  prior to introduction of the carrier strip material. In the centered position, sidewalls  114  of the mold block  110  closely abut against cap surfaces  72  and lower surfaces  115  of block  110  abut the upper surface  80  of cap flange  78  to isolate and protect the snout  70  of cap  68  within the mold cavity  112 . A bottom half of the mold block (not shown in  FIG. 11 ) closes against the lower surfaces  115  of block  110  and material to form the carrier strip  36  is introduced into the mold cavity. Sealing abutment between mold block surfaces  114 ,  115  and cap surfaces  72 ,  80  prevent the carrier material from entering cavity  112  and thereupon invading the transponder aperture  76 . Material forming the carrier strip  36 , it will be appreciated, is filled up to the surface  80  of the flange  78 , entirely encapsulating the antenna  32  and partially encapsulating the base  52  of the transponder module  34 . 
   The mold halves are separated and the annular carrier strip with integrally captured antenna and transponder package removed from the mold. The subject annular assembly is thereafter affixed to the inner liner  22  of the tire  12  in the manner described previously and shown in  FIGS. 1 and 6 . The transponder module  34  may be oriented flat against the carrier strip as shown in  FIG. 3  or oriented on end as shown in broken line at  34 ′. Whichever orientation is utilized, the strip material  36  serves to maintain the transponder and antenna in a preferred optimal mutual orientation and the transponder module  34  in an optimal orientation relative to the tire cavity. The port  76  in the upper surface  74  of the cap  68  is exposed to the tire cavity  24  free of the carrier strip  36 . Direct communication between the tire cavity  24  and sensors mounted to the circuit board  98  is thereby facilitated through port  76 . The stepped and tapered configuration of the transponder module  34  is preferred in order to make the module self centering in the mold and to allow a seal to be established between the mold and outer surfaces of the transponder module. The annular path defined between ledge surface  80  and vertical surface, sidewalls  72  of cap  68  and the inward facing surfaces of mold sidewalls  114  deters the flow of carrier material into cavity  112 . Were the flow of material not inhibited, the material could enter cavity  112  and proceed through port  76  to the circuit board  90 . The electronics and sensors mounted upon circuit board  98  are thus protected during the process of molding carrier strip  36  around the transponder module base  52  by the stepped configuration of the transponder housing. 
   In practice, the annular apparatus consisting of the antenna and coupled transponder is typically manufactured and assembled to a tire by the tire manufacturer form purchased components. The transponder  34 , transceiver  48 , and antenna wire  32  are sourced from supplying parties. The supplier typically identifies the components by identification data that may be stored within ASIC RAM memory in the transponder module  34 . The tire manufacturer then assembles the transponder  34 , antenna  32 , and encapsulating ring  32  together to create the finished annular assembly. The annular assembly is thereafter affixed to a tire by the alternative methods described above. Pursuant to the invention, it is advantageous for the tire manufacturer to input tire identification data into ASIC memory whereby the identity of the tire and transponder components may be stored, cross-referenced, and retrieved as necessary. 
   The annular assembly  10  is affixed to tire  12  and, with a corresponding transceiver  48 , supplied to a vehicle manufacturer. At some point along the production line, the tires are mounted to a specific vehicle and the transceiver  48  of each tire  12  mounted to the body of the vehicle opposite the antenna ring. The transceiver  48  is then either hard wired or connected via wireless transmission to a display unit. The display unit may either be a dedicated unit to the TPMS or visual and/or audible communication of measured data from transponders  34  may be integrated into dashboard displays. 
   While the method of the invention is practiced preferably by the annular antenna and transponder assembly described previously, the invention is not intended to be so limited. Other TPMS, such as valve stem mounted transponders, that communicate tire information by various means may utilized and practice the claimed method. Tire information generally measured in TPMS include pressure and temperature. However, the subject method is functional regardless of the specific physical properties of the tire that are monitored. 
     FIG. 15  illustrates a typical TPMS  200  installed on a motor vehicle  202  (shown in dashed lines) having four pneumatic tires  204   a  . . .  204   d  installed on four respective wheels (not shown). A transponder  206   a  . . .  206   d  of a type described previously or alternatively configured in a manner known to the industry is associated with each of the tires  204   a  . . .  204   d , respectively. Each transponder impresses variable information (data) in a suitable format upon the transmitted signal indicative of a measured condition such as tire pressure or conditions (e.g. tire pressure, temperature, revolutions), as well as optionally impressing fixed information (e.g. tire ID, transponder I.D.) on the transmitted signal, as well as optionally responding to information which may be present on a signal which is received by the transponder. 
   The transponders  206   a  . . .  206   d  are preferably passive transponders as described above that obtain their operating power from an RF signal which is provided by an on-board interrogator  208  that is mounted within the vehicle. 
   The interrogator  208  comprises an RF transmitter  212  (e.g. for powering passive transponders), an RF receiver  214 , control logic  216  which may include a microprocessor (uP), and a display device  218  such as a visual display and optionally including an audible alarm. Antennas (ANT)  210   a  . . .  210   d  are disposed on the vehicle  202 , preferably adjacent the tires  204   a  . . .  204   d , respectively, such as in the wheel wells of the vehicle. The antennas  210   a  . . .  210   d  are suitably ferrite loopstick antennas. In this manner, closes coupling can be effected between the transponder annular antennas and the vehicle antennas, thereby facilitating identifying which of the several wheels on a vehicle has a sensed low pressure condition. 
   In use, the interrogator  2108  powers the transponders  206   a  . . .  206   d  which, in turn, transmit data indicative of a measured condition (e.g. tire air pressure) back to the interrogator  208 . In any such system, it is desirable to have efficient and effective coupling of signals between the fixed antennas  210   a  . . .  210   d  and the moving transponders. The annular antennas coupled to the transponders facilitate such an effective and efficient coupling. Communication between the transceivers  210   a  . . .  210   d  and the central receiver  214  may by means of hardwire or by means of an RF communications link. 
     FIG. 16  illustrates an alternative embodiment of a TPMS  300  installed on a vehicle  302  (shown in dashed lines), such as a typical passenger vehicle having four pneumatic tires  304   a  . . .  304   d  installed on four respective wheels (not shown). The installation may occur along a production assembly line in the case of an OEM application or as replacement tires in a post-manufacturing environment. 
   The vehicle  302  is preferably equipped with an RS-485 (or equivalent) multiplexed serial data bus  306  controlled by an on-board vehicle computer  308  having an RS-485 interface  310 . Computer  308  is commonly referred to as an electronic control module or “ECU”. The data bus and computer network are installed during production line OEM assembly of a vehicle. A central display unit  312  is connected either directly to the computer  308  or is operatively connected (as shown) to the computer  308  via the data bus  306 . In the absence of an existing vehicle data bus, a dedicated data bus may be provided so as to allow communication between the TPMS and the vehicle ECU. 
   Each of the four tires  304   a  . . .  304   d  is equipped with an electronic module (“Tag”)  320   a  . . .  320   d , as described previously, and associated sensor (not shown) capable of monitoring one or more conditions such as air pressure and air temperature within the tire and transmitting a radio frequency (RF) signal indicative of the monitored conditions within the respective vehicle tire. 
   The system  300  comprises four TPMS wheel station readers  330   a  . . .  330   d , each associated with a respective one of the tires  304   a  . . .  304   d  and located in close proximity therewith, such as mounted within the wheel wells of the vehicle. Each reader  330   a  . . .  330   d  comprises an antenna (not shown) that is attached at a fixed position on the vehicle adjacent the tire, within the near field of the respective tag  320 . Each reader  330  is connected to a source of power (as indicated by the lines terminating in circles and triangles) and is connected to the multiplexed serial data bus  306  for individually communicating with the on-board computer  308 . Each reader  330   a  . . .  330   d  comprises a suitable data transceiver such as the DS36277 Dominant Mode Multipoint Transceiver by National Semiconductor to facilitate two-way data transmission via the data bus  306 . 
   In this manner, monitored condition information carried by the RF signals from the respective tags  320  can be decoded and provided to the on-board computer  308  for subsequent display  312  to the operator of the vehicle. Regarding communications occurring over the serial data bus  306 , multiplex (MUX) wiring, or networking, is generally well known, and has been introduced in automotive applications to address the increase in complexity and the number of onboard electronic devices in automobiles. 
   The tags  320  are commonly a transponder, an antenna, a receiver, a transmitter, a pressure sensor, a temperature sensor, and an ASIC chip that preferably has a unique identification (ID) number associated therewith. The tags are typically manufactured and assembled by an electronics manufacturer. The manufacturer of the tires  304   a  . . .  304   d  pursuant to the invention sources the tags  320  and incorporates a tag  320  into a respective tire  304  either by means of an annular assembly as described above or other known alternative means. The tire manufacturer pursuant to the invention may load a unique tire identification (ID) number into the transponder ASIC chip whereby the transponder and tire identification is cross-referenced. 
   In an OEM application, a vehicle manufacturer typically mounts the tires  304  to the vehicle tire to the vehicle body at some point along the assembly line. An OEM commonly maintains a database containing a unique identification (ID) number for each vehicle manufactured. At the conclusion of the assembly process, it is common to run a diagnostic test of the ECU systems for the vehicle in order to assure proper operational capability. The result of such a diagnostic test is then down loaded into the OEM central database and maintained as part of a permanent vehicle record. 
   Referring to  FIG. 17 , the subject tire tag initialization procedure  400  is illustrated in block diagram form. The initialization procedure proceeds generally from tag to vehicle. Responsibility for certain steps in the procedure is divided preferably between the tag manufacturer  402 , the tire manufacturer  404 , and the OEM  406  as shown. However, the invention is not intended to be so restricted. Responsibility for every step in the process may be consolidated into one party if desired. Alternatively, the steps within the procedure may be realigned and assigned to more or less contributing parties if desired. 
   The tag manufacturer  402  as shown in  FIG. 17  operates in the performance of steps  408 ,  410 , and  412 , culminating in a transfer of the tire tag to the tire manufacturer in step  414 . Step  408  comprises the manufacture of the transponder and tag and may include such components in a housing of the type described above herein. The calibration  410  of the pressure and temperature sensors within the transponder and tag and the date for tag functions is next performed. The Tag ID and calibration data is then written into memory in step  412 , followed by the transfer  414  of the tag to the tire manufacture. 
   The tire manufacturer  404  (preferably but not necessarily) continues the procedure by the manufacture of the tag and antenna assembly, indicated as step  416 . As described above, an annular apparatus provides distinct advantages in communication between the tag and a vehicle mounted reader. However, other tag and antenna configurations are possible such as valve stem mounted transponders. The tire tag and antenna assembly is then integrated into a tire  418  and the tire identification data is loaded into ASIC memory  420 . An OEM part number(s) for the tire and tag/antenna assembly may also be loaded into ASIC memory  422 . The tire may thereafter be conveyed  424  to the vehicle OEM  406 . After incorporation of the tire into an assembly line vehicle and interconnection of the tag reader into the vehicle data bus line, the OEM proceeds with system initialization  426  including writing the VIN (vehicle identification number) into tire tag ASIC memory and reading tire information data from the ASIC memory into vehicle ECU memory (step  428 ). The tire identification data is then uploaded (step  430 ) from the ECU to an OEM database where the information is maintained for future reference. The car, post assembly, is then transferred (step  432 ) typically to a vehicle dealer. The dealer, servicing party, or any other party having a need, may thereafter have the capability to read identification data for each tire and rewrite VIN data from the vehicle (step  434 ). 
   The advantages of the subject method are manifold. First, integrating tag, transponder, tire, and vehicle identification data into a single accessible database affords a convenient means for tracking the history of each component throughout the useful life of the vehicle. Substitution of parts or tires for original equipment can be ascertained in the event of an accident to aid in accident reconstruction or analysis. Moreover, when replacement of tires or tag/transponder parts becomes necessary, identification of original components will ensure the suitability of replacement parts. Thus, there will always be a capability to cross-reference the identity of the vehicle with the identity of the tires and TPMS components via the database created at the vehicle assembly stage. 
   Further, the subject method affords a means for creating such a database efficiently and effectively with minimal inconvenience to the sundry manufactures in the chain. The tag manufacturer can conveniently incorporate tag information into the ASIC memory prior to transfer of the tag to the tire manufacturer. Likewise, the tire manufacturer may incorporate tire identification information (including optional OEM part numbers) into the ASIC memory prior to transferring the tire to the OEM. The OEM also is provided with a convenient time and means for reading the tire and tag identification information into ECU memory and uploading such information to the OEM database. No dedicated external readers and antennas are required along the production line for reading tire tag identification transmissions. Rather, the reading of tire identification data is preferably deferred until an end-of-line diagnostic is conducted on the ECU and related systems. Access to data from the tire TPMS (ASIC) is thereby timely and efficient and such data may be uploaded to a database for future reference. 
   While the above sets forth a preferred embodiment and alternative embodiments of the subject invention, the invention is not intended to be so limited. Other embodiments that will be apparent to those skilled in the art and which utilize the teachings herein set forth, are intended to be within the scope and spirit of the present invention. By way of example, with no intent to limit the range of alternative embodiments, the subject correlation between tire identification and vehicle identification is not limited to passive sensor systems. Active systems, that is, systems including a tire or wheel mounted power source may be devised and employed using the subject method. For example, a valve stem sensor device having a battery supply can be deployed. In addition, while the embodiments discussed employ a tire mounted transponder and sensor package, the invention need not be so limited. A valve stem or wheel mounted transponder device may be utilized in the practice of the invention if so desired.