FIELD OF THE INVENTION

[0001] The present subject matter concerns Tire Pressure Monitoring Systems (TPMS) for use with vehicle tires. More particularly, the present subject matter concerns enhancements to such systems, especially apparatus and methodology for automatically identifying the location of each tire with respect to each wheel position associated with a vehicle.

BACKGROUND OF THE INVENTION

[0002] The incorporation of electronic devices with pneumatic tire and wheel structures yields many practical advantages. Tire electronics may include sensors and other components for relaying tire identification parameters and also for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, tread wear, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate proper tire parameters or vehicle systems operation and/or performance.

[0003] Yet another potential capability offered by electronics systems integrated with tire structures corresponds to asset tracking and performance characteristics for commercial as well as other type vehicular applications. Commercial truck fleets, aviation craft and earth mover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Radio frequency identification (RFID) tags can be utilized to provide unique identification for a given tire, enabling tracking abilities for a tire. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems.

[0004] One particular area of concern with regard to Tire Pressure Monitoring Systems (TPMS) and their associated sensors relates to methodologies for designating the relationship of the sensors to the vehicles. More particularly, it may be significant to the proper operation of a particular application to know the physical location of the sensors with respect to their location relative to the vehicle. More precisely, it may be important or even critical to a particular application to know the specific physical location of each tire/wheel combination with respect to the particular vehicle on which the tires are mounted. [0005] One example of such location sensitive applications may include tire pressure- monitoring applications wherein it may be important to a vehicle operator to know that the right front tire, for example, as opposed to a rear tire, is currently experiencing a low-pressure condition. Such a low-pressure condition may become of critical importance if the low- pressure condition suddenly becomes extreme upon occurrence of, for example, a rapid air loss, which may affect directional control or stability of the vehicle especially if the vehicle is being operated at highway speeds. An additional example of a sensor location significant application is one where the tire sensors may be actively employed in the real time control of certain functions of the vehicle. Examples of these functions may include anti-lock or antiskid braking systems.

[0006] In conventional implementations of Tire Pressure Monitoring Systems, the issue of tire/wheel location identification has been recognized and has generally been addressed in one of three ways. In a first implementation of tire location identification systems, the relative location of particular tire/wheel combinations has been entered manually into a memory or storage element associated with the TPMS. Examples of systems employing this technique may be found in U. S. Published Applications US 2003/0128108 Al to Knapp, published July 10, 2003 and US 2003/0164031 Al to Nantz et al., published September 4,

2003. In the '108 device, either a detected change in pressure or a predetermined sequence of tire rotation triggers a request to manually enter data relative to new tire locations on the vehicle. In the '031 device, following tire rotation or replacement, when the vehicle is stationary, a sequence is initiated wherein each tire on the vehicle is physically struck in a predetermined sequence so that a sensor in or on the tire detects the impact and reports an identification of the struck tire which is recorded as a specific vehicle location for future use. [0007] A second previously known methodology for identifying vehicle specific tire locations involves what may be described as interrogator/responder type systems. U.S. Published Applications US 2002/0067285 Al to LiU, published June 6, 2002; U.S. 2002/0084895 Al to Dixit et a!., published July 4, 2002; U.S. 2002/0084896 Al to Dixit et ajL, published July 4, 2002; and US 2002/0196137 Al to Poirier et a!., published December

26, 2002, exemplify such interrogator/responder type systems. According to this second

) methodology, a transceiver associated with a particular tire sensor periodically transmits a request to a tag physically located in a tire well to transmit information contained within the tag. The contained information may include previously stored information relating to the specific location of the wheel well on the vehicle. The transmitted information is then received by the tire sensor associated transceiver and stored for future use. [0008] A third previously known methodology for identifying vehicle specific tire locations relates to methodologies for automatically determining relative tire location based on operational characteristics of the tires during specific operations of the vehicle. Generally these methodologies involve the determination of specific tire locations based on differences in wheel rotational speed during turns. More specifically, the vehicle may be driven in one or more specific patterns and the TPMS device determines the specific location of each tire/wheel combination based on knowledge of the specific direction(s) driven by the vehicle and measurements of the differing speeds of the tire/wheel combinations. U.S. Published Applications US 2002/0092345 Al to Van Niekerk et a!., published July 18, 2002; US 2002/0092347 Al to Niekerk et a!., published July 18, 2002; and US 2003/0076222 Al to Fischer et al.. published April 24, 2003 representatively illustrate this third methodology for identifying vehicle specific tire locations.

[0009] While various implementations of vehicle tire location identifying arrangements have been developed, and while various combinations of location information recording methodologies have been provided using conventional technologies, no design has emerged

that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.

SUMMARY OF THE INVENTION

[0010] In view of the recognized features encountered in the prior art and addressed by the present subject matter, an improved methodology for identifying mounting locations for tire/wheel combination on a vehicle has been developed. It should be noted that although the principal portion of the remainder of the present disclosure may refer to the use of permanent magnet based arrangements integrated with or proximate to a wheel mounting location structure and paired with appropriate sensors to detect magnetic fields generated by the permanent magnets, such use is not intended to represent a limitation of the present technology as, in fact, such arrangements may be provided as combinations with a variety of other devices or elements producing and/or detecting fields other than magnetic fields as will be more fully described later. Further, it should be borne in mind that the relative positions of field generating and field sensing elements may be interchanged. Thus, for example, in the non-limiting example of using permanent magnets and magnetic field sensing elements, the only requirement is that such elements are respectively associated with relatively moving components. In addition, although the term "wheel well" may be used herein, such should be construed to include not only the physical structure of what is commonly referred to as a wheel well, but also the general area proximate to an area of a vehicle where tire and wheel combinations may normally be mounted. Note, for example, that so called "flat bed" trucks as well as other vehicles may not actually have a "well" partially surrounding a tire/wheel combination even though the tire/wheel combination is physically mounted to, for example, an axle attached to the vehicle.

[0011] In an exemplary configuration, a wheel mounting location specific tag is placed in or proximate to one or more of a vehicle's wheel mounting locations (e.g. wheel wells). In an exemplary embodiment, such wheel well specific tags may comprise one or more magnets configured to provide a unique magnetic pattern associated with each wheel well. More generally, an exemplary wheel well specific tag may comprise an encoded field generator designed to uniquely identify a wheel well in which the tag may be affixed. As previously

mentioned, the present technology is principally directed to an encoded array of permanent magnets; however, such is not a limitation of the present technology. [0012] In further exemplary embodiments of the present technology, encoded arrays of various field generating devices or mechanisms may be employed to provide wheel well specific identification tags. Non-exhaustive examples of such include not only the permanent magnets previously mentioned but also electro-magnets, both paired with appropriate sensors for detecting the generated magnetic or electromagnetic fields. Non-exhaustive examples of appropriate sensors for detecting magnetic or electromagnetic fields include the following: Fluxgate, Superconducting Quantum Interference Device (SQUID), Hall Effect, Magnetoresistive, Proton Precession, and Optically Pumped sensors. It should be clearly understood that the present technology is not limited to magnetic or electromagnet fields and paired sensors but rather envisions the use of any available field generating device or mechanism paired together with appropriate field sensors. Such field generating devices or mechanisms and sensors may include, but are not limited to the use of, magnetic and electromagnetic fields, optical wavelength radiation, nuclear radiation, and acoustic wavelength radiation. As should be readily apparent to those of ordinary skill in the art in light of the present disclosure, the present technology may make use of virtually any detectable field producing element, device or system to implement the present technology. [0013] With more specific reference to an exemplary embodiment of the present subject matter, an array of permanent magnets may be configured to produce a unique magnetic pattern in each wheel well. The unique magnetic pattern provides a coded informational identification of the location of the various wheel wells. Sensors associated with a tire mounted on a wheel within the wheel well detect the unique magnetic pattern in each wheel well when the tire rotates and, thereby, positively identifies the exact location of the tire relative to the vehicle on which it is mounted.

[0014] Positive aspects of this form of information transmission methodology include circuit simplification and power savings. For example, instead of requiring the tire pressure monitoring system circuitry associated with the tire to transmit an interrogation signal and listen for a transmitted response as in some previously known systems, the sensed encoded information is conveyed through the detection of continuously produced magnetic fields. Such methodology provides for the transmission of encoded location information without the necessity of providing an additional power source.

[0015] Another positive aspect of this type of information transmission is that the information transmitted is not subject to human data entry error as may occur with other previously known systems. For example, in the previously known systems wherein manual entry of data is required, such data may be entered incorrectly or not at all. In addition, even in those known systems wherein an automatic determination of tire/wheel combination location is undertaken, such determinations must be initiated through human interaction and relies on specific human actions such as operating the vehicle in a specific manner so as to provide an opportunity for the previously known automatic detection systems to perform their detection operations.

[0016] In accordance with aspects of certain embodiments of the present subject matter, methodologies have been developed to lessen the influence of human error and/or oversight on the accuracy of tire/wheel combination location detection devices and systems. More particularly, methodologies have been developed to lessen the possibility of data entry errors and/or non-entry of data in Tire Pressure Monitoring Systems wherein the accurate identification of tire/wheel combination locations is of importance to the operation of vehicle devices and systems.

[0017] In accordance with certain aspects of other embodiments of the present subject matter, methodologies have been developed to lessen any influence resulting from improper operation of a vehicle during a tire/wheel location identification phase of a setup or calibration operation associated with a Tire Pressure Monitoring System following tire replacement or periodic tire rotation.

[0018] In accordance with yet still further aspects of other embodiments of the present subject matter, methodologies have been provided to lessen the overall electrical power requirements for Tire Pressure Monitoring Systems that include tire/wheel location identification requirements for proper operation.

[0019] Additional aspects of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variations to the specifically illustrated, referred and discussed features and elements hereof may be practiced in various embodiments and uses of the present subject matter without departing from the spirit and scope of the subject matter. Variations may include, but are not limited to, substitution of equivalent means,

features, or steps for those illustrated, referenced, or discussed, and the functional, operational, or positional reversal of various parts, features, steps, or the like. [0020] Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of the present subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents (including combinations of features, parts, or steps or configurations thereof not expressly shown in the figures or stated in the detailed description of such figures). Additional embodiments of the present subject matter, not necessarily expressed in the summarized section, may include and incorporate various combinations of aspects of features, components, or steps referenced in the summarized objects above, and/or other features, components, or steps as otherwise discussed in this application. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the remainder of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

[0022] Figure 1 diagrammatically illustrates an operational relationship between a field generating tag assembly mounted in a wheel well and a sensor associated with a Tire Pressure

Monitoring System in accordance with the present technology;

[0023] Figure 2 diagrammatically illustrates the relative motion between the unique field generators of the present technology past a field sensor device;

[0024] Figures 3 (a) - 3(d) diagrammatically illustrate basic configurations of a unique field pattern generating tag device with which the methodologies of the present subject matter may be implemented; and

[0025] Figures 4(a) - 4(d) illustrate corresponding exemplary waveforms produced by a sensor associated with the automatic tire location detection component of a Tire Pressure

Monitoring System in accordance with the preset technology.

[0026] Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features or elements of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] As discussed in the Summary of the Invention section, the present subject matter is particularly concerned with methodologies for tire/wheel location data entry in Tire Pressure Monitoring Systems wherein the specific location of the various tires mounted on a vehicle is of importance to vehicle or system operations.

[0028] Selected combinations of aspects of the disclosed technology correspond to a plurality of different embodiments of the present subject matter. It should be noted that each of the exemplary embodiments presented and discussed herein should not insinuate limitations of the present subject matter. Features or steps illustrated or described as part of one embodiment may be used in combination with aspects of another embodiment to yield yet further embodiments. Additionally, certain features may be interchanged with similar devices or features not expressly mentioned which perform the same or similar functions. [0029] Reference will now be made in detail to the presently preferred embodiments of the subject auto-location systems and methodologies. Referring now to the drawings, Figure 1 diagrammatically illustrates a tire 10 mounted to a wheel 20 within a wheel well 30. Unique field pattern generator 40 is secured within the wheel well 30 such that a field- detecting sensor 50 mounted internally of tire 10 may detect the unique field pattern generated by the unique field pattern generator 40. Field-detecting sensor 50 may be included as a part of a tire pressure monitoring system (TPMS) or may be a stand-alone sensor that may or may not be associated with a TPMS. It should be kept in mind that while it is significant to the present technology that the unique field pattern generator 40 and field- detecting sensor 50 are provided to uniquely identify the location of a particular tire/wheel combination on a vehicle and the technology is herein presented for use in or with a TPMS, such use is not necessarily limiting to the present technology as such location information may be useful in any number of environments.

[0030] Referring still to Fig. 1, it will be observed that field-detecting sensor 50 has been illustratively displayed as mounted in the crown portion of tire 10 while unique field

generator 40 has been illustrated as mounted in a corresponding location on the inside surface of wheel well 30. Fig. 1 also illustrates alternative mounting locations for the field-detecting sensor and unique field pattern generator so that field-detecting sensor 50' may be located in a side wall portion of tire 10 while unique field pattern generator 40' may be located in a portion of the wheel well facing the side wall portion of tire 10. In practice field-detecting sensor 50 or 50' and unique field pattern generators 40 or 40' may be located in any portion of the tire and wheel well respectively or on the contrary, so long as the selected locations provide for relative motion between the two devices upon rotation of the tire with movement of the vehicle.

[0031] Referring now to Fig. 2, diagrammatically illustrated therein is a representation of the relative locations for field-detecting sensor 50 and unique field pattern generator 40. As indicated by arrow 70, in use, field-detecting sensor 50 and unique field generator 40 move relative to each other such that individual field generating elements 80, 82, 84, 86 move past field-detecting sensor 50 seriatim so that field-detecting sensor 50 produces a series of signals, as will be more fully described later, to generate a unique location identifying signal. [0032] With further reference to Fig. 2, unique field pattern generator 40 has been represented as comprising a plurality of individual field generating elements 80, 82, 84, 86 mounted on a carrier or support surface 60. In practice, one or more of the field generating elements 80, 82, 84, 86 may not actually be physically present, as will be explained more fully later. Moreover, the illustrated support surface 60 may, in fact, comprise the inside surface of the wheel well, per se, or may comprise an actual support surface to which the individual field generating elements are attached, which support surface 60 may then be secured to the inside surface of a wheel well.

[0033] Referring now to Figs. 3(a) - 3(d), illustrated therein is an exemplary arrangement of a first embodiment of unique field pattern generator 40. In this exemplary embodiment, a plurality of permanent magnets may be employed as the field generating elements. Each of Figs. 3 (a) - 3(d) individually represent a unique arrangement of individual field generating elements that may represent, respectively, a left front tire, a right front tire, a left rear tire, and a right rear tire. In this exemplary embodiment, the unique field pattern generating element arrangement representing a left front tire is illustrated in Fig. 3 (a) by two permanent magnets 100, 130 oriented to present their respective south poles directed toward field-detecting

sensor 50. Field generating elements 110, 120 in this example, comprise null elements, that is, these positions are empty and, thereby, characterized by a null field. [0034] Referring now to Fig. 3(b), an exemplary configuration for a unique field pattern representing a right front tire is illustrated. In this example, field generating elements 200 and 230 are similar to elements 100 and 130 respectively of Fig. 3 (a) and, in like manner, may be implemented as permanent magnets oriented to present their respective south poles directed toward field-detecting sensor 50. As in the Fig. 2(a) arrangement, field generating element 210, like field generating element 110 comprises a null element so that a null, i.e., no, field is generated at that location. Field generating element 220, on the other hand, may be embodied as a permanent magnet oriented to present its north pole directed toward field- detecting sensor 50. The unique field pattern thus present by the "right front" tire unique field pattern generator is represented sequentially as a south pole, a null, a north pole, and a south pole. These pole or null representations are illustrated symbolically in Figs 3(a) - 3(d) as circles with respective over struck characters "X" representing a south pole, "+" representing a north pole and "/" representing a null or no field (i.e., no magnet present). [0035] With reference then to Figs. 3(c) and 3(d) it will be understood that Fig. 3(c), representing a unique field pattern indicating a left rear tire is sequentially represented by elements 300, 310, 320, and 330 each respectively implemented by a south pole, a north pole, a null, and a south pole. Fig. 3(d), in a similar manner, represents a unique field pattern indicating a right rear tire by sequential presentation of elements 400, 410, 420, and 430 representing respectively a south pole, a north pole, a north pole and a south pole. [0036] It should be understood that the arrangements illustrated in Figs. 3(a) - 3(d) are exemplary only both as to pole and null configuration as well as total number of field generating elements. For example, different unique combinations as well as different numbers of field generating elements may be employed. Such variations might be occasioned by a desire to provide symmetrical coding for reasons that will be explained more fully later, as well as a desire to accommodate more than four tire positions. Again, it should also be borne in mind that the implementation of the field generators in this embodiment as permanent magnets is exemplary only as the use of many other types of field generators is also anticipated as previously noted.

[0037] Attention is now directed to Figs. 4(a) - 4(d) that display representations of an exemplary form of detected signal produced by field-detecting sensor 50. As is evident from

their symmetry with respect to Figs. 3(a) - 3(d), respectively, Figs. 4(a) - 4(d) display a relatively negatively going pulse in those instances where a south pole of the field generating permanent magnet is presented to the field-detecting sensor 50, a relatively positively going pulse in those instances where a north pole of the field generating permanent magnet is presented to the field-detecting sensor 50, and no pulse when a null field, i.e. no magnet, is presented to the field-detecting sensor 50.

[0038] Returning briefly to Figs. 3(a) - 3(d), it will be remembered that, in each instance, the sequence of fields generated all began and ended with a magnetic south pole (represented in the figures by a circle over struck with an "x") being presented to the field-detecting sensor 50. Such presentation of a south pole to the field-detecting sensor functions as both a "start" pulse for the sequence as well as an "end" pulse. The use of such a unique field at the beginning and end of each sequence coupled with the omission of such unique field as one of the possible pulses which might be considered the "data" portion of the sequence provides a relatively simple mechanism for detecting the beginning and ending of a data sequence. [0039] Finally, there is the possibility of misinterpretation of the data generated by the unique field pattern generating elements as sensed by the field-detecting sensors depending on the rotational direction of the tires. It is often the case that a vehicle will begin motion in a "reverse" direction, as, for example, by "backing out" of a parking location. The present technology addresses this issue by providing two solutions. A first alternative is to select a symmetrical code as the individual unique field patterns generated. Such a selection would completely avoid the issue of determining the travel direction of the vehicle. A second alternative solution might involve the use of information obtained from an onboard vehicle local area network (LAN) that, for other purposes, may be aware or informed of the direction of travel of the vehicle. In this instance the tire/wheel location determination system could be directed to either ignore readings from the unique field pattern generator if the vehicle is traveling in a reverse direction or be directed to decode readings from the unique field pattern generator in reverse order to obtain the correct data.

[0040] While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude

inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.