Improved tyre pressure sensor

Abstract

A tyre pressure sensor connectable to a valve stem of a tyre so as to sense a pressure of a gas within the tyre. The sensor has a radio transmitter indicating a position of a wheel on which it is installed in relation to a vehicle. The radio transmitter may transmits (i) a wheel position, or (ii) a sensor identifier to a receiving unit, the sensor identifier correlating to a position of a wheel in relation to a vehicle. The tyre pressure sensor may have a human comprehensible wheel position indicator defining a position of a wheel in relation to a vehicle.

Description

IMPROVED TYRE PRESSURE SENSORFIELD OF THE INVENTION

[0001] . The present invention relates generally to the field of tyre pressure monitoring devices, systems, and methods of implementing same. In particular, the invention relates to implementation in relation to vehicles having large numbers of tyres such as trucks and trailers.BACKGROUND TO THE INVENTION

[0002] . It is well accepted for reasons of safety, economy and vehicle performance that pneumatic tyres on a vehicle should be maintained within limits.

[0003] . Tyre pressure sensors that are able to report pressure data in real time have played a crucial role in enhancing vehicle safety, fuel efficiency, and overall performance.

[0004] . The concept of monitoring tyre pressure dates back to the late 1980s when automakers recognized the importance of maintaining optimal tyre pressure for safety and performance. Early systems were indirect, relying on the anti-lock braking system (ABS) to detect changes in wheel rotation speed, indirectly inferring tyre pressure variations.

[0005] . The first direct tyre pressure monitoring systems (TPMS) emerged in the late 1990s, employing pressure sensors installed inside each tyre to directly measure the pressure. These sensors transmitted data to a central receiver, alerting the driver when tyre pressure deviated from the recommended levels.

[0006] . In the early 2000s, concerns over road safety and fuel efficiency led to regulatory initiatives. In the United States, the TREAD (Transportation Recall Enhancement, Accountability, and Documentation) Act mandated the inclusion of TPMS in all light vehicles (under 10,000 pounds) manufactured after September 1, 2007.

[0007] . TPMS sensors evolved from simple pressure switches to more sophisticated sensors, including piezoelectric and capacitive sensors, offering better accuracy and reliability.

[0008] . Early sensors used replaceable batteries, but advancements led to the development of sensors with longer-lasting, non-replaceable batteries.

[0009] . As technology progressed, TPMS became an integral part of a vehicle's overall control systems. Integration with on-board computers allowed for real-time monitoring, data logging, and integration with other safety features.

[0010] . Modern TPMS utilizes wireless communication protocols such as Bluetooth and Radio-Frequency Identification (RFID) for transmitting data between sensors and the vehicle's electronic control unit (ECU). This enables more efficient and reliable data transfer.[Oi l]. Aftermarket TPMS typically comprise a series of sensors, each of which sealingly screws onto the inflation valve stem of each tyre. The sensor depresses the core of the tyre valve thereby exposing a pressure transducer in the sensor to the pressurised gas (nitrogen or air) within the tyre. The sensor may be of the flow-through type that includes a gas input port to allow for tyre inflation while the sensor is fitted. Alternatively, the sensor may be of the dead-end type which must be removed from the valve stem to allow for tyre inflation.

[0012] . Monitoring tyres vehicles that have large numbers of wheels (and therefore tyres) such as trucks, trailers, caravans and the like presents particular problems. . Upon installation, each sensor must be paired (generally by BlueTooth™) to the receiver / display unit in the driver’ s cabin. Furthermore, the position of each tyre sensor must be correlated to the position displayed to the driver such that the driver knows which pressure value pertains to which tyre. As will be appreciated this can be an involved task where many wheels are involved.

[0013] . It is often the case that a truck may tow a number of different trailers, and accordingly the where a new trailer is connected the receiver / display unit in the truck cabin must be reconfigured to correlate each sensor device with the respective tyre position.

[0014] . A further problem arises when a sensor device must be replaced, and again there presents a need to correlate the relevant tyre position as represented on the receiver / display unit with the replacement sensor.

[0015] . These difficulties generally dissuade transport fleet managers from implementing TPMS technology at the expense of safety, economy and performance.

[0016] . It is an aspect of the present invention to provide an improvement to prior art tyre pressure sensors, sensor systems, and methods for implementing same. It is a further aspect of the present invention to provide a useful alternative to prior art tyre pressure sensors, sensor systems, and methods for implementing same.

[0017] . The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.SUMMARY OF THE INVENTION

[0018] . In a first aspect, but not necessarily the broadest aspect, the present invention provides a tyre pressure sensor connectable to a valve stem of a tyre so as to sense a pressure of a gas within the tyre, the sensor comprising a radio transmitter configured to indicate a position of a wheel on which it is installed in relation to a vehicle.

[0019] . In one embodiment of the first aspect, the radio transmitter transmits (i) a wheel position, or (ii) a sensor identifier to a receiving unit, wherein the sensor identifier correlates to a position of a wheel in relation to a vehicle.

[0020] . In one embodiment of the first aspect, the tyre pressure sensor comprises or is associated with a human comprehensible wheel position indicator defining a position of a wheel in relation to a vehicle.

[0021] . In one embodiment of the first aspect, the wheel position indicator is displayed on or about the tyre pressure sensor, or forms a part of the tyre pressure sensor, or is completely or partially enclosed within the tyre pressure sensor.

[0022] . In one embodiment of the first aspect, the wheel position indicator is displayed on a tag attached to the tyre pressure sensor, or on packaging associated with the tyre pressure sensor.

[0023] . In one embodiment of the first aspect, the wheel position indicator is comprehensible by way of output by an electronic device in data communication with the tyre pressure sensor

[0024] . In one embodiment of the first aspect, the wheel position indicator is comprehensible by visual, tactile, or audio means.

[0025] . In one embodiment of the first aspect, the sensor identifier is correlated with the position of a wheel position by way of a remote device in data communication with the tyre pressure sensor.

[0026] . In one embodiment of the first aspect, the remote device has stored thereon a lookup table correlating the sensor identifier with a wheel position indicator.

[0027] . In one embodiment of the first aspect, the remote device is an output device configured to output pressure information in a human-comprehensible form.

[0028] . In one embodiment of the first aspect, the wheel position indicator indicates the position by way of any one or more of a numeral, a letter, a graphic, an icon, a symbol, a drawing, and a sound.

[0029] . In one embodiment of the first aspect, the sensor identifier is a computer-readable string.

[0030] . In one embodiment of the first aspect, the sensor identifier is unique in relation to the identifier of other tyre pressure sensors within a set of sensors operable in relation to a single receiving unit.

[0031] . In one embodiment of the first aspect, the tyre pressure sensor comprises an orientation indicator configured to output a variable orientation in response to the rotation of a wheel on which the tyre pressure sensor is installed.

[0032] . In one embodiment of the first aspect, the tyre pressure sensor comprises a gas input port and a gas output port, wherein the gas input port is configured to input a tyre inflating gas and the gas output port in configured to output the tyre inflating gas into the tyre valve stem.

[0033] . In a second aspect, the present invention provides a collocation of tyre pressure sensors, each of the tyre pressure sensors according to any embodiment of the first aspect.

[0034] . In one embodiment of the second aspect, each of the tyre pressure sensors are tethered together or disposed within a volume.

[0035] . In one embodiment of the second aspect, the volume is defined by a holding vessel, a transport vessel, a product package, a retail package, a transport package, a postal package, a courier package, a “click and collect” package, and a bag.

[0036] . In one embodiment of the second aspect, each sensor identifier is unique and each wheel position indicator is unique within the collocation.

[0037] . In one embodiment of the second aspect, each of the wheel position indicators together define each of the wheel positions in a wheeled apparatus.

[0038] . In one embodiment of the second aspect, the wheeled apparatus has greater than 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 wheels.

[0039] . In one embodiment of the second aspect, the wheeled apparatus is selected from: a heavy vehicle, a truck, a van, a trailer, and a caravan.

[0040] . In one embodiment of the second aspect, the wheeled apparatus is not a passenger vehicle.

[0041] . In a third aspect, the present invention provides a tyre pressure monitoring system comprising: a plurality of tyre pressure sensorseach of which comprises a radio transmitter, and a receiving unit configured to receive a radio signal encoding a sensed pressure value, the receiving unit being further configured to receive (i) a wheel location, or (ii) an identifier, or (iii) a signal strength from each of the plurality of tyre pressure sensors, wherein the wheel location, the identifier, the signal strength or a variation in signal strength is used to identify the wheel location of one or more of the plurality of tyre pressure sensors.

[0042] . In one embodiment of the third aspect, each of the plurality of tyre pressure sensors is according to any embodiment of the first aspect.

[0043] . In one embodiment of the third aspect, the plurality of tyre pressure sensors is 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 tyre pressure sensors.

[0044] . In one embodiment of the third aspect, the receiving unit is configured to output in human comprehensible form, a wheel position and a tyre pressure value sensed by a sensor at that wheel position, as transmitted by each of the plurality of tyre pressure sensors.

[0045] . In one embodiment of the third aspect, the receiving unit is configured to correlate an identifier or a signal strength, or a signal strength variability with a wheel position.

[0046] . In one embodiment of the third aspect, the correlation is facilitated by an electronic lookup table access correlating the sensor identifier or the signal strength, or the signal strength variability with a wheel position.

[0047] . In one embodiment of the third aspect, the receiving unit is configured to discern the wheel position by reference to the identifier or the signal strength, or the signal strength variability.

[0048] . In one embodiment of the third aspect, the receiving unit is configured to store the sensor identifier, the signal strength or the signal strength variability of a signal transmitted by the radio transmitter of each of the plurality of tyre pressure sensors.

[0049] . In one embodiment of the third aspect, the receiving unit is configured to correlate each of the saved sensor identifiers, signal strengths, or signal strength variabilities with a wheel position.

[0050] . In one embodiment of the third aspect, the tyre pressure sensor comprises an orientation indicator configured to output a point or a region in the angular rotation of a wheel on which the tyre pressure sensor is installed.

[0051] . In one embodiment of the third aspect, the signal strength is determined at a predetermined point or region in the angular rotation of a wheel on which the tyre pressure sensor is installed.

[0052] . In one embodiment of the third aspect, upon introduction of a new tyre pressure sensor, or upon reintroduction of an existing tyre pressure sensor, into the system the receiving unit by processor means: compares (i) the signal strength or the signal strength variability of a signal transmitted by the radio transmitter of the new or the reintroduced tyre pressure sensor to (ii) one or more of the stored signal strengths or signal strength variabilities, identifies a stored signal strength or signal strength variability that is the same as, or the most similar to, the signal strength of a signal or signal strength variability transmitted by the radio transmitter of the new or the reintroduced existing tyre pressure sensor, and correlates the new or the reintroduced tyre pressure sensor to the wheel position correlated with the identified stored signal strength or signal strength variability.

[0053] . In one embodiment of the third aspect, the step of correlating comprises correlating an identifier of the new tyre pressure sensor with the wheel position correlated with the identified stored signal strength.

[0054] . In one embodiment of the third aspect, the step of correlating comprises maintaining an existing correlation between the identifier of the reintroduced tyre pressure sensor and a wheel position.

[0055] . In a fourth aspect, the present invention provides a wheeled apparatus having any embodiment of the third aspect fitted thereto, wherein each of the plurality of tyre pressure sensors is fitted to the valve stem of a tyre mounted on a wheel at the wheel position according to the sensor identifier of the respective tyre pressure sensor.

[0056] . In one embodiment of the fourth aspect, each of the plurality of tyre pressure sensors is fitted to a valve stem of a tyre mounted on a wheel at the wheel position according to the sensor identifier of the respective tyre pressure sensor.

[0057] . In one embodiment of the fourth aspect, each of the tyre pressure sensors comprises or is associated with a human comprehensible wheel position indicator defining a position of a wheel in relation to a vehicle, and each of the plurality of tyre pressure sensors is connected to a valve stem of a tyre mounted on a wheel at the wheel position according to the wheel position indicator of the respective tyre pressure sensor.

[0058] . In one embodiment of the fourth aspect, the receiving unit is located such that a driver of the vehicle is able to comprehend an output therefrom.

[0059] . In one embodiment of the fourth aspect, the receiving unit is located in or about a driver cabin of the vehicle.

[0060] . In one embodiment of the fourth aspect, the wheeled apparatus is selected from: a heavy vehicle, a truck, a van, a trailer, and a caravan.

[0061] . In one embodiment of the fourth aspect, the wheeled apparatus is not a passenger vehicle.

[0062] . In a fifth aspect, the present invention provides a method of installing a tyre pressure monitoring system on a wheeled apparatus, the method comprising the steps of: providing the system of any embodiment of the third aspect, for each of the plurality of tyre pressure sensors locating a wheel of the wheeled apparatus which correlates therewith by reference to the sensor identifier or the wheel position indicator, and connecting each of the sensors to the valve stem of the tyre mounted on its correlating wheel.

[0063] . In one embodiment of the fifth aspect, the method comprises locating the receiving unit in or about a driver cabin of the wheeled apparatus.

[0064] . In one embodiment of the fifth aspect, he wheeled apparatus is selected from: a heavy vehicle, a truck, a van, a trailer, and a caravan.

[0065] . In one embodiment of the fifth aspect, the wheeled apparatus is not a passenger vehicle.

[0066] . In a sixth aspect, the present invention provides a method of replacing a tyre pressure sensor of the tyre pressure monitoring system of any embodiment of the third aspect when installed on a wheeled apparatus, the method comprising the steps of: identifying a wheel of wheeled apparatus to which the tyre pressure sensor to be replaced is installed, providing a replacement tyre pressure sensor having a sensor identifier or a wheel position indicator that correlates to the position of the wheel, removing the tyre pressure sensor to be replaced, and installing the replacement tyre pressure sensor to the tyre on the wheel.

[0067] . In a seventh aspect, the present invention provides a method of automatically identifying a wheel position of a tyre pressure sensor having a radio transmitter, the method comprising the steps of: by a radio receiver unit, determining a signal strength or a variability in signal strength, correlating the determined signal strength or signal strength variability to a signal strength or signal strength variability expected or previously determined for a tyre pressure sensor installed to a wheel position.

[0068] . In one embodiment of the seventh aspect, the signal strength is determined at a point or within a range of the angular rotation of the wheel on which the tyre pressure sensor is installed.BRIEF DESCRIPTION OF THE FIGURES

[0069] . FIG. 1 illustrates diagrammatically a preferred tyre pressure monitoring system of the present invention as applied to a vehicle having 6 wheels. The dashed lines represent radio communication connections.

[0070] . FIG. 2 illustrates diagrammatically a preferred means for the automatic identification of the wheel position for a tyre pressure that is a replacement for a previously installed sensor, or for a sensor that has been reinstalled.

[0071] . FIG. 3 illustrates a preferred flow-through type of aftermarket tyre pressure sensor of the present invention.

[0072] . FIG. 4A illustrates a preferred dead-end type of aftermarket tyre pressure sensor of the present invention.

[0073] . FIG. 4B is an alternative view of the tyre pressure sensor of FIG. 4A

[0074] . Unless otherwise indicated herein, features of the drawings labelled with the same numeral are taken to be the same features, or at least functionally similar features, when used across different drawings.

[0075] . The drawings are not prepared to any particular scale or dimension and are not presented as being a completely accurate presentation of the various embodiments.DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

[0076] . After considering this description it will be apparent to one skilled in the art how the invention is implemented in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example only, and not limitation. As such, this description of various alternative embodimentsshould not be construed to limit the scope or breadth of the present invention. Furthermore, statements of advantages or other aspects apply to specific exemplary embodiments, and not necessarily to all embodiments, or indeed any embodiment covered by the claims.

[0077] . Throughout the description and the claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.

[0078] . Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may.

[0079] . The present invention is predicated at least in part on the inventors’ discovery that improvements in after-market or retro-fitted tyre pressure monitoring systems are found where each pressure sensor of the system is uniquely configured so as to guide the installer to fit the each sensor to a certain vehicle wheel. For example, a truck may have three axles (front, center, and rear) with each axle having two wheels (passenger-side, and driver-side). In that circumstance the system comprises six tyre pressure sensors: a first sensor to be fitted to the passenger-side wheel of the front axle, a second sensor to be fitted to the driverside wheel of the front axle, a third sensor to be fitted to the passenger-side wheel of the center axle, a fourth sensor to be fitted to the driver-side wheel of the center axle, a fifth sensor to be fitted to the passenger-side wheel of the rear axle, and a sixth sensor to be fitted to the driver-side wheel of the rear axle

[0080] . Each of the first to sixth sensors may bear a unique marking informing the installer as to which wheel the sensor is to be fitted. Having regard to the marking on each sensor, the installer fits each sensor to its respective wheel (more particularly, to the valve stem of the tyre on the respective wheel).

[0081] . Each of the first to sixth sensors may comprise a radio transmitter configured to transmit a unique sensor identifier to a receiver / display unit of the system. The receiver / display unit will, from the sensor identifier, correlate the sensor concerned to a certain wheel of the vehicle. That correlation can be safely made because the installer has, by reference to the sensor markings, installed each sensor on a certain wheel.

[0082] . Each of the first to sixth sensors may also transmit a sensed tyre pressure to the receiving unit. Based on the sensor identifier of the sensor transmitting the sensed tyre pressure, the receiving unit is able to display a wheel position (e.g. front axle, driver-side) and the pressure of the tyre mounted at the wheel position (e.g. 8.5 bar).

[0083] . The arrangement described above is applicable to vehicles having more than six wheels, and is readily scalable to vehicles having 18 wheels or even more. In the case of an 18 wheel vehicle, the truck portion typically has 10 wheels and the trailer portion typically has 10 wheels.

[0084] . Reference is made to FIG. 1 showing a tyre pressure monitoring system as fitted to a six wheel vehicle. The vehicle has 3 axles (10, 15, 20), and 6 wheels (25, 30, 35, 40, 45, 50) each of which has a pneumatic tyre fitted thereto. Each wheel (25, 30, 35, 40, 45, 50) is fitted with a tyre pressure sensor (55, 60, 65, 70, 75, 80).

[0085] . Each sensor (55, 60, 65, 70, 75, 80) is unique within the system insofar that each is marked visually to define a certain wheel position, as follows:

[0086] . The first numeral in the marking (1, 2 or 3) identifies the axle (first, second and third respectively, counted from the front of the vehicle). The second numeral in the marking ( 1 or 2) identifies the wheel of the axle concerned (first and second, counted from the left side of the vehicle, in plan view).

[0087] . An exemplary tyre pressure sensor (60a) for that marked 60 in FIG. 1 is shown in the drawing. The sensor (60a) is marked “12” indicating the wheel position, being on the first axle and being second from the left. It is contemplated that other schemes may be used for indicating the wheel position. For example, letters may be used with the axles marked A, B, C, and the wheels (i) or (ii).

[0088] . As will appreciated, an axle may have more than two wheels and in which case the respective wheels may be identified 1, 2, 3, 4 etc; or A, B,C, D; or by any other suitable means.

[0089] . In some embodiments, a graphic may be used to indicate the wheel position. Such an embodiment may be a graphic of plan view of a vehicle with an arrow directed to the relevant wheel position.

[0090] . In other embodiments, the sensor may be configured to output a synthesised human voice that speaks the wheel position upon actuation of a sensor button.

[0091] . The wheel position indicator may be marked on the sensor body, or formed into the sensor in some manner such as by embossing.

[0092] . In some embodiments the sensor itself does not display any wheel position indicator. One example is where the sensor is presented in vendible form within packaging, and the packaging is marked with the wheel position indicator for the sensor contained therein. As another example, the sensor may be presented with a removable tag or stickerwhich bears the wheel position indicator. In another example, the sensor forms a wired or wireless data connection with a smartphone of the installer, and the smartphone receives the wheel position indicator from a memory module of the sensor and displays the wheel position indicator on the touchscreen. Another possibility is that the sensor comprises an RFID tag encoding the wheel position indicator, the RFID tag being readable by a competent device. In another example, the sensor is marked with an optical code, such as a QR code which is captured by a smartphone camera, which in turn causes the smartphone to interrogate a remote server via the Internet to obtain the wheel position indicator for that sensor, and the indicator is displayed on the smartphone touchscreen.

[0093] . Each sensor has a sensor identifier that is unique within the system. The sensor identifier is transferred wirelessly to a receiver / display unit (85), and is typically digitally encoded. The sensor identifier may be a representation of a string of numbers, letters, symbols, and the like. An exemplary encoding system is the American Standard Code for Information Interchange. In that regard, the sensor identifier may be a coded version of the wheel position indicator although such embodiments may have the disadvantage of requiring storage and transmission more than is necessary data. More typically, the sensor identifier is a simple string of binary.

[0094] . The sensor identifier may be used to pre-program and configure each sensor in a system to accord to their respective wheel locations in the system.

[0095] . The sensors may be one of two types - General Purpose (GP) sensor, or Last Byte (LB) sensor. Both serve as integral parts of the autolocation mechanism (i.e. the means by which the receiver / display unit discerns the wheel position location of a sensor) to be discussed further infra

[0096] . 1. GP Sensors: These devices are programmed with a unique ID code as the sensor identifier, allowing them to be used across various positions in a vehicle fleet. The autolocation logic, driven by the 5 Most Significant Bits (5x MSB), provides precise positioning for GP sensors, making them suitable for targeted orders.

[0097] . 2. LB Sensors: Operating based on the 8 Least Significant Bits (8x LSB), LB sensors follow a specific algorithmic rule for position assignment. This approach enables sequential manufacturing, ensuring efficient production runs for diverse positions, overcoming the impracticality of ordering specific runs for each position.

[0098] . The autolocation mechanism may operate with either the 5 Most Significant Bits (5x MSB) for GP sensors or the 8 Least Significant Bits (8x LSB) for LB sensors. The first 5 bits of the ID code distinguish GP sensors, and if these bits are all zeros, the sensor is identified as LB.

[0099] . GP Sensor Position Assignment:

[0100] . The autolocation logic for GP sensors assigns positions based on the predetermined numbering convention related to wheel position and axle. This convention, intricately linked to the 5x MSB, ensures that each GP sensor is assigned a specific identifier, simplifying the manufacturing and integration processes.

[0101] . The first 5 bits of the ID code are designated for GP sensors.

[0102] . There are 24 distinct positions based on the first 5 bits, accurately identified by the axle and position numbers.

[0103] . Positions are determined by the logic outlined below:

[0104] . Type Position DEC HEX 5x MSB

[0105] . GP SENSOR POS 11 1 01 00001

[0106] , GP SENSOR POS 12 2 02 00010

[0107] , GP SENSOR POS 13 3 03 00011

[0108] , GP SENSOR POS 14 4 04 00100

[0109] , GP SENSOR POS 21 5 05 00101

[0110] , GP SENSOR POS 22 6 06 00110

[0111] . GP SENSOR POS 23 7 07 00111

[0112] , GP SENSOR POS 24 8 08 01000

[0113] . GP SENSOR POS 31 9 09 01001

[0114] , GP SENSOR POS 32 10 0A 01010

[0115] , GP SENSOR POS 33 11 OB 01011

[0116] , GP SENSOR POS 34 12 0C 01100

[0117] , GP SENSOR POS 41 13 0D 01101

[0118] , GP SENSOR POS 42 14 0E OH IO

[0119] , GP SENSOR POS 43 15 OF 01111

[0120] , GP SENSOR POS 44 16 10 10000

[0121] , GP SENSOR POS 51 17 11 10001

[0122] , GP SENSOR POS 52 18 12 10010

[0123] , GP SENSOR POS 53 19 13 10011

[0124] , GP SENSOR POS 54 20 14 10100

[0125] , GP SENSOR POS 61 21 15 10101

[0126] , GP SENSOR POS 62 22 16 10110

[0127] , GP SENSOR POS 63 23 17 Wi l l

[0128] , GP SENSOR POS 64 24 18 11000

[0129] . LB sensors, on the other hand, operate based on the 8 x LSB, employing an algorithmic rule for position assignment. This sequential logic allows for efficient production runs, overcoming challenges associated with specific manufacturing orders for each position.

[0130] . If the first 5 bits are all zeros, the position is encoded in the LB.

[0131] . The LB positions follow a sequential numbering algorithm, resulting in uneven distribution.

[0132] . There are still 24 positions available, assigned based on the algorithmic rule following:

[0133] . LB Decimal LB HEX LB Binary Position

[0134] , 0 00 00000000 POS 12

[0135] . 1 01 00000001 POS 13

[0136] , 2 02 00000010 POS 21

[0137] , 3 03 00000011 POS 22

[0138] . 4 04 00000100 POS 23

[0139] , 5 05 00000101 POS 24

[0140] . 6 06 00000110 POS 31

[0141] , 7 07 00000111 POS 32

[0142] , 8 08 00001000 POS 33

[0143] . 9 09 00001001 POS 34

[0144] , 10 0A 00001010 POS 12

[0145] . 11 OB 00001011 POS 13

[0146] , 12 OC 00001100 POS 21

[0147] , 13 OD 00001101 POS 22

[0148] . 14 OE 00001110 POS 23

[0149] . 15 OF 00001111 POS 24

[0150] . 16 10 00010000 POS 31

[0151] . 17 11 00010001 POS 32

[0152] , 18 12 00010010 POS 33

[0153] . 19 13 00010011 POS 34

[0154] , 20 14 00010100 POS 12

[0155] . 21 15 00010101 POS 13

[0156] . 22 16 00010110 POS 21

[0157] , 23 17 00010111 POS 22

[0158] . 24 18 00011000 POS 23

[0159] , 25 19 00011001 POS 24

[0160] . 26 1A 00011010 POS 31

[0161] . 27 IB 00011011 POS 32

[0162] , 28 1C 00011100 POS 33

[0163] . 29 ID 00011101 POS 34

[0164] , 30 IE 00011110 POS 12

[0165] , 31 IF 00011111 POS 13

[0166] , 32 20 00100000 POS 21

[0167] , 33 21 00100001 POS 22

[0168] , 34 22 00100010 POS 23

[0169] , 35 23 00100011 POS 24

[0170] , 36 24 00100100 POS 31

[0171] . 37 25 00100101 POS 32

[0172] , 38 26 00100110 POS 33

[0173] , 39 27 00100111 POS 34

[0174] , 40 28 00101000 POS 12

[0175] , 41 29 00101001 POS 13

[0176] , 42 2A 00101010 POS 21

[0177] , 43 2B 00101011 POS 22

[0178] , 44 2C 00101100 POS 23

[0179] , 45 2D 00101101 POS 24

[0180] , 46 2E 00101110 POS 31

[0181] . 47 2F 00101111 POS 32

[0182] , 48 30 00110000 POS 33

[0183] , 49 31 00110001 POS 34

[0184] , 50 32 00110010 POS 12

[0185] , 51 33 00110011 POS 13

[0186] , 52 34 00110100 POS 21

[0187] , 53 35 00110101 POS 22

[0188] , 54 36 00110110 POS 23

[0189] , 55 37 00110111 POS 24

[0190] , 56 38 00111000 POS 31

[0191] . 57 39 00111001 POS 32

[0192] , 58 3A 00111010 POS 33

[0193] , 59 3B 00111011 POS 34

[0194] , 60 3C 00111100 POS 12

[0195] , 61 3D 00111101 POS 13

[0196] , 62 3E 00111110 POS 21

[0197] , 63 3F 00111111 POS 22

[0198] , 64 40 01000000 POS 23

[0199] , 65 41 01000001 POS 24

[0200] , 66 42 01000010 POS 31

[0201] , 67 43 01000011 POS 32

[0202] , 68 44 01000100 POS 33

[0203] , 69 45 01000101 POS 34

[0204] , 70 46 01000110 POS 12

[0205] , 71 47 01000111 POS 13

[0206] , 72 48 01001000 POS 21

[0207] , 73 49 01001001 POS 22

[0208] , 74 4A 01001010 POS 23

[0209] , 75 4B 01001011 POS 24

[0210] , 76 4C 01001100 POS 31

[0211] . 77 4D 01001101 POS 32

[0212] , 78 4E 01001110 POS 33

[0213] , 79 4F 01001111 POS 34

[0214] , 80 50 01010000 POS 12

[0215] , 81 51 01010001 POS 13

[0216] , 82 52 01010010 POS 21

[0217] , 83 53 01010011 POS 22

[0218] , 84 54 01010100 POS 23

[0219] , 85 55 01010101 POS 24

[0220] , 86 56 01010110 POS 31

[0221] , 87 57 01010111 POS 32

[0222] , 88 58 01011000 POS 33

[0223] , 89 59 01011001 POS 34

[0224] , 90 5A 01011010 POS 12

[0225] , 91 5B 01011011 POS 13

[0226] , 92 5C 01011100 POS 21

[0227] , 93 5D 01011101 POS 22

[0228] , 94 5E 01011110 POS 23

[0229] , 95 5F 01011111 POS 24

[0230] , 96 60 01100000 POS 31

[0231] , 97 61 01100001 POS 32

[0232] , 98 62 01100010 POS 33

[0233] , 99 63 01100011 POS 34

[0234] , 100 64 01100100 POS 12

[0235] , 101 65 01100101 POS 13

[0236] , 102 66 01100110 POS 21

[0237] , 103 67 01100111 POS 22

[0238] , 104 68 01101000 POS 23

[0239] , 105 69 01101001 POS 24

[0240] , 106 6A 01101010 POS 31

[0241] , 107 6B 01101011 POS 32

[0242] , 108 6C 01101100 POS 33

[0243] , 109 6D 01101101 POS 34

[0244] , 110 6E 01101110 POS 12

[0245] , 111 6F 01101111 POS 13

[0246] , 112 70 01110000 POS 21

[0247] , 113 71 01110001 POS 22

[0248] , 114 72 01110010 POS 23

[0249] , 115 73 01110011 POS 24

[0250] , 116 74 01110100 POS 31

[0251] , 117 75 01110101 POS 32

[0252] , 118 76 01110110 POS 33

[0253] , 119 77 01110111 POS 34

[0254] , 120 78 01111000 POS 12

[0255] , 121 79 01111001 POS 13

[0256] , 122 7A 01111010 POS 21

[0257] , 123 7B 01111011 POS 22

[0258] , 124 7C 01111100 POS 23

[0259] , 125 7D 01111101 POS 24

[0260] , 126 7E 01111110 POS 31

[0261] , 127 7F 01111111 POS 32

[0262] , 128 80 10000000 POS 33

[0263] , 129 81 10000001 POS 34

[0264] , 130 82 10000010 POS 12

[0265] , 131 83 10000011 POS 13

[0266] , 132 84 10000100 POS 21

[0267] , 133 85 10000101 POS 22

[0268] , 134 86 10000110 POS 23

[0269] , 135 87 10000111 POS 24

[0270] . 136 88 10001000 POS 31

[0271] , 137 89 10001001 POS 32

[0272] , 138 8A 10001010 POS 33

[0273] . 139 8B 10001011 POS 34

[0274] , 140 8C 10001100 POS 12

[0275] , 141 8D 10001101 POS 13

[0276] , 142 8E 10001110 POS 21

[0277] , 143 8F 10001111 POS 22

[0278] . 144 90 10010000 POS 23

[0279] . 145 91 10010001 POS 24

[0280] , 146 92 10010010 POS 31

[0281] , 147 93 10010011 POS 32

[0282] , 148 94 10010100 POS 33

[0283] , 149 95 10010101 POS 34

[0284] , 150 96 10010110 POS 12

[0285] , 151 97 10010111 POS 13

[0286] , 152 98 10011000 POS 21

[0287] , 153 99 10011001 POS 22

[0288] , 154 9A 10011010 POS 23

[0289] , 155 9B 10011011 POS 24

[0290] , 156 9C 10011100 POS 31

[0291] , 157 9D 10011101 POS 32

[0292] , 158 9E 10011110 POS 33

[0293] , 159 9F 10011111 POS 34

[0294] , 160 AO 10100000 POS 12

[0295] , 161 Al 10100001 POS 13

[0296] , 162 A2 10100010 POS 21

[0297] , 163 A3 10100011 POS 22

[0298] , 164 A4 10100100 POS 23

[0299] , 165 A5 10100101 POS 24

[0300] , 166 A6 10100110 POS 31

[0301] , 167 A7 10100111 POS 32

[0302] , 168 A8 10101000 POS 33

[0303] , 169 A9 10101001 POS 34

[0304] , 170 AA 10101010 POS 12

[0305] , 171 AB 10101011 POS 13

[0306] , 172 AC 10101100 POS 21

[0307] , 173 AD 10101101 POS 22

[0308] , 174 AE 10101110 POS 23

[0309] , 175 AF 10101111 POS 24

[0310] , 176 BO 10110000 POS 31

[0311] . 177 Bl 10110001 POS 32

[0312] , 178 B2 10110010 POS 33

[0313] , 179 B3 10110011 POS 34

[0314] , 180 B4 10110100 POS 12

[0315] , 181 B5 10110101 POS 13

[0316] , 182 B6 10110110 POS 21

[0317] , 183 B7 10110111 POS 22

[0318] , 184 B8 10111000 POS 23

[0319] , 185 B9 10111001 POS 24

[0320] , 186 BA 10111010 POS 31

[0321] , 187 BB 10111011 POS 32

[0322] , 188 BC 10111100 POS 33

[0323] , 189 BD 10111101 POS 34

[0324] , 190 BE 10111110 POS 12

[0325] , 191 BF 10111111 POS 13

[0326] , 192 CO 11000000 POS 21

[0327] , 193 Cl 11000001 POS 22

[0328] , 194 C2 11000010 POS 23

[0329] , 195 C3 11000011 POS 24

[0330] , 196 C4 11000100 POS 31

[0331] , 197 C5 11000101 POS 32

[0332] , 198 C6 11000110 POS 33

[0333] , 199 C7 11000111 POS 34

[0334] , 200 C8 11001000 POS 11

[0335] , 201 C9 11001001 POS 14

[0336] , 202 CA 11001010 POS 11

[0337] , 203 CB 11001011 POS 14

[0338] , 204 CC 11001100 POS 11

[0339] , 205 CD 11001101 POS 14

[0340] , 206 CE 11001110 POS 11

[0341] , 207 CF 11001111 POS 14

[0342] , 208 DO 11010000 POS 11

[0343] , 209 DI 11010001 POS 14

[0344] , 210 D2 11010010 POS 11

[0345] , 211 D3 11010011 POS 14

[0346] , 212 D4 11010100 POS 11

[0347] , 213 D5 11010101 POS 14

[0348] , 214 D6 11010110 POS 11

[0349] , 215 D7 11010111 POS 14

[0350] , 216 D8 11011000 POS 11

[0351] , 217 D9 11011001 POS 14

[0352] , 218 DA 11011010 POS 11

[0353] , 219 DB 11011011 POS 14

[0354] , 220 DC 11011100 POS 11

[0355] , 221 DD 11011101 POS 14

[0356] , 222 DE 11011110 POS 11

[0357] , 223 DF 11011111 POS 14

[0358] , 224 E0 11100000 POS 41

[0359] , 225 El 11100001 POS 42

[0360] , 226 E2 11100010 POS 43

[0361] , 227 E3 11100011 POS 44

[0362] , 228 E4 11100100 POS 41

[0363] , 229 E5 11100101 POS 42

[0364] , 230 E6 11100110 POS 43

[0365] , 231 E7 11100111 POS 44

[0366] , 232 E8 11101000 POS 41

[0367] , 233 E9 11101001 POS 42

[0368] , 234 EA 11101010 POS 43

[0369] , 235 EB 11101011 POS 44

[0370] . 236 EC 11101100 POS 41

[0371] , 237 ED 11101101 POS 42

[0372] , 238 EE 11101110 POS 43

[0373] . 239 EF 11101111 POS 44

[0374] , 240 FO 11110000 POS 41

[0375] , 241 Fl 11110001 POS 42

[0376] , 242 F2 11110010 POS 43

[0377] , 243 F3 11110011 POS 44

[0378] . 244 F4 11110100 POS 41

[0379] . 245 F5 11110101 POS 42

[0380] , 246 F6 11110110 POS 43

[0381] . 247 F7 11110111 POS 44

[0382] , 248 F8 11111000 POS 51

[0383] . 249 F9 11111001 POS 52

[0384] , 250 FA 11111010 POS 53

[0385] . 251 FB 11111011 POS 54

[0386] , 252 FC 11111100 POS 61

[0387] , 253 FD 11111101 POS 62

[0388] . 254 FE 11111110 POS 63

[0389] . 255 FF 11111111 POS 64

[0390] , According to this rule each 256 LB sensors produced will have the following position spread:

[0391] . Position Count each 256

[0392] , POS H 12

[0393] , POS 12 20

[0394] , POS 13 20

[0395] , POS 14 12

[0396] , POS 21 20

[0397] , POS 22 20

[0398] , POS 23 20

[0399] , POS 24 20

[0400] , POS 31 20

[0401] , POS 32 20

[0402] , POS 33 20

[0403] , POS 34 20

[0404] , POS 41 6

[0405] , POS 42 6

[0406] , POS 43 6

[0407] , POS 44 6

[0408] , POS 51 1

[0409] , POS 52

[0410] , POS 53 1

[0411] , POS 54 1

[0412] , POS 61 1

[0413] , POS 62 1

[0414] , POS 63 1

[0415] , POS 64 1

[0416] . This particular means of identifying wheel position based on a GP or LB sensor enables easier manufacturing, allowing for ordering a specific GP sensor position, or a combination of positions based upon the LB rule.

[0417] . In terms of radio transmission of the sensor identifier to the receiver / display unit(85), the sensor may utilise any prior art means such as BlueTooth™ or Ant+™. Low energy implementations are preferred so as to extend the battery life of the sensor. In any event, the sensor may comprise a radio communications module in operable connection with a compact antenna.

[0418] . The sensor may additionally comprises electronic memory that is non-volatile for the permanent storage of the sensor identifier. The electronic memory is in operable connection with the radio communications module, to allow the latter to input the former for transmission to the receiver / display.

[0419] . The sensor comprises an electronic pressure transducer, being any type deemed suitable by a skilled artisan. The transducer produces a digital output that is representative of a gas pressure sensed from within the tyre. The radio communications module of the sensor may be configured to input also the digital sensor output of the pressure transducer.

[0420] . As shown in FIG. 1 and in respect of sensor (30), the sensor identifier and pressure value are both transmitted by radio means to the receiver / display unit (85). Such transmission also occurs for the other sensors (25, 35, 40, 45, 50) although in each case the sensor identifier is different. The receiver / display unit (85) may be configured tosequentially input data from each of the sensors (25, 30, 35, 40, 45, 50), such that at any instant the received data is known to originate from a single sensor. By such operation, the sensor identifier of one sensor is never associated with the pressure value output by another sensor. Alternatively, the sensor identifier and pressure value may be transmitted as a data packet to the receiver / display unit (85), and upon input of the data packet by the receiver / display unit (85), the contents of the single data packet is taken to originate from a single sensor.

[0421] . The receiver / display unit (85) comprises a radio communication module configured to receive the sensor identifier and the pressure value transmitted to it by each of the sensors (25, 30, 35, 40, 45, 50). The receiver / display unit (85) comprises program instructions stored in electronic memory and being executable by an on-board processor to discern the wheel position of the sensor (25, 30, 35, 40, 45, 50) from which the pressure value originates. The sensor identifier is a key element in performing that task, functioning as an input for the program instructions. In some embodiments the program instructions refer to a lookup table stored in non-volatile electronic memory. The lookup table associates a sensor identifier with a wheel position, and given the sensor identifier that is received and input into the program instructions is able to discern from which wheel position any associated pressure value has originated.

[0422] . In some embodiments, a lookup table is not required and the sensor identifier itself provides sufficient information to locate the relevant wheel. For example, the sensor identifier may be “11” (in binary: 00001011), and in which case the program instructions may be configured to separate that string into a first character (“1”) and a second character (“1”) and identify the relevant wheel position as the first wheel on the first axle (i.e. sensor 25 in FIG. 1). In this regard, the sensor identifier may function also as the wheel position indicator, given that the former and latter should both be unique within the system.

[0423] . The receiver / display unit (85) of the system drawn in FIG. 1 is intended to be mounted in the vehicle cabin, and in visual and optionally audio proximity to the vehicle driver. The receiver / display unit (85) comprises a visual display (90) (such as a TFTscreen) displaying a graphic (95) representing the axles and positions of the vehicle wheels of the vehicle. For each wheel, the display (90) displays a pressure value (one indicated, 100), typically expressed in units of PSI or Bar.

[0424] . In the example drawn in FIG. 1, the driver’s side tyre on the third axle (i.e. the tyre(50) having the sensor (80)) is below the expected pressure and an alarm icon (105) is therefore displayed. To draw the driver’s attention to the abnormally low tyre pressure, a speaker (110) emits a tone.

[0425] . The system may be configured to automatically relearn a specific sensor’s wheel position in the event of sensor replacement or reinstallation. This function significantly simplifies maintenance procedures.

[0426] . When a sensor is replaced or reinstalled, the receiver / display unit can be prompted by the user to select the corresponding wheel location from a list, and the chosen wheel location is from that point in time associated with the new sensor's identification number, enabling accurate and reliable monitoring of tyre pressure.

[0427] . Alternatively the system may be configured to automatically detect the presence of a new sensor and assigned its position according to a numbering convention and the predetermined sensor identifier (GP, LB or other).

[0428] . Reinstallation or replacement may also be facilitated by a consideration of theReceived Signal Strength Indicator (RSSI) of a sensor introduced into the system as compared to the RSSI of the previous sensor. At first setup a learning the system incorporated into the receiver / display unit learns the RSSI received by the sensors in the positions learnt. Each sensor will typically be a different distance and / or have different materials between it and the receiver / display unit. Accordingly, the RSSI for each sensor as detected at setup should be unique. A replacement sensor, before being assigned to the same position of a previously missing, should have an RSSI measurement comparable to that learnt for that position at system setup.

[0429] . Accuracy in wheel location detection by way of RSSI may be improved by measuring the signal strength of a sensor (for both an original sensor and a reinstalled or replaced sensor) when the sensor is at a predetermined point or region with reference to its 360 degrees of angular rotation about the wheel axle. As will be appreciated, the signal strength for a sensor as received by the receiver unit changes as the wheel rotates becoming weaker as the sensor is rotated away from the receiver unit and stronger as it rotates toward the receiver unit. Measuring the signal strength at a predetermined angular position (for example, at the 12 o’clock position) removes the signal strength variability arising from rotation of the wheel to which the sensor is attached. More faithful detection of the wheel position is therefore expected.

[0430] . In these embodiments, the sensor may be fitted with angular rotation position detection means configured to indicate the position of the sensor. For example, the angular rotation detection means may indicate that the sensor is at the highest point in its travel (the 12 o’clock position, or 0 degrees for example), or the lowest point (the 6 o’clock position, or 180 degrees, for example), or at any other point in its travel. To that end, the sensor may comprise an orientation indicator. The output of the orientation indicator changes as the wheel rotates and the orientation of tyre pressure sensor rotates. Such indicators include are magnetometers, accelerometers, and gyroscopes, as well as various combinations of these devices often referred to as IMUs (inertial measurement devices). An IMU suitable for this application may be a MPU-9255 (Invensense Inc; CA), being a multi-chip module (MCM) consisting of two dies integrated into a single QFN package. One die houses the 3-Axis gyroscope and the 3-Axis accelerometer. The other die houses the AK8963 3-Axis magnetometer from Asahi Kasei Microdevices Corporation. Hence, the MPU-9255 is a 9 axis MotionTracking device that combines a 3-axis gyroscope, 3-axis accelerometer, 3- axis magnetometer and a Digital Motion Processor™ (DMP) all in a small 3x3xlmm package available as a pin-compatible upgrade. In the present application, all functionality of the MPU-9255 may not be required.

[0431] . The signal strength may be measured a single angular rotation position, or at multiple positions (such a 12 o’clock, 3 o’clock, 6 o’clock and 9 o’clock). The signal strength may be recorded against each angular rotation position for the original sensor, and also for a reinstalled or replaced sensor. In determining the position of a reinstalled or replaced sensor, the signal strengths at each of the angular rotation positions are compared with the signal strengths originally recorded for that wheel position.

[0432] . In addition or alternatively to any scheme described supra, the variation in signal strength alone for a sensor as the wheel rotates may be used to uniquely identify the wheel position, and without any reference to the angular rotation of the wheel. The variability may be considered in terms of a maximum and a minimum signal strength, an amplitude of signal strength variation, or a graph of signal strength, or a mathematical function of signal strength having a time domain, or any other manner of qualitatively or quantitatively describing the signal variability. In such embodiments, the need for an orientation indicator in the tyre pressure is obviated.

[0433] . In the embodiments above reliant on signal strength data and angular rotation data to automatically determine wheel location, the data is preferred stored in linked association in electronic memory. The electronic memory may reside within the receiver / display unit.

[0434] . As will be appreciated, embodiments reliant on a variation in signal strength require the wheel concerned to be in rotation so as to generate the signal strength variability required for wheel position identification.

[0435] . Reference is made to FIG. 2 showing a wheel (30) having a tyre pressure sensor(60) installed thereon. The tyre pressure sensor (60) is shown in four alternative angular rotation positions (60a, 60b, 60c, 60d) as occurs upon rotation of the wheel (30). The tyre pressure sensor (60) comprises an orientation indicator capable of determining when the tyre pressure sensor (60) is at each of the four angular rotation positions (60a, 60b, 60c, 60d), and a radio transmitter. A receiver unit (85) fixedly mounted on the vehicle receives a radio signal from each of the four angular rotation positions (60a, 60b, 60c, 60d). Thestrength of the received signal at each angular rotation position (60a, 60b, 60c, 60d) is different given the differing intervening distances dl, d2, d3 and d4. The four signal strengths form a “fingerprint” that is likely unique to the location of the wheel (30) on the vehicle. The fingerprint for wheel (30) is stored in the receiving unit (85). Where the tyre pressure sensor (60) is replaced, rotation of the wheel (30) with the new sensor generates a new fingerprint. Because the new fingerprint correlates to the stored fingerprint, the receiving unit (85) determines that the new sensor must, or is likely to be, installed on the wheel (30).

[0436] . Multi Trailer Logic - New Trailer ID learningThe system may be installed on a vehicle comprising a truck having a certain number of wheels, and a trailer having a certain number of wheels. However, in the course of fleet operation a truck may be used to pull any of a number of expected trailers. Accordingly, the system may be configured to remain operable irrespective of which of the expected trailers is connected to the truck, such that the tyre pressure sensors fitted to each of the expected trailers is operable with the sensors of the truck and the receiver / display unit mounted in the truck cabin. When the system is in a stable state (i.e. with the truck associated with any of the expected trailers) the system remains in that stable state unless it detects that one of the expected trailers is missing. If one of the expected trailers is not missing, no system action is performed.

[0437] . A missing trailer is detected as follows. If the receiver / display in the truck cabin receives no information for any of the sensors of its expected trailers for a certain configurable time (say, 5 minutes), the system will flag a missing trailer.

[0438] . If the receiver / display in the truck cabin is receiving information for any of the sensors of its expected trailers and a new trailer (being fitted with new sensors) is added on the end, the system will not detect it as the system is configured to assume a sable state only for the expected trailers. The tyre pressure sensors of the new trailer may therefore need to admitted into the system by a fresh setup procedure.

[0439] . Reference is made to FIG. 3 showing in greater detail an exemplary tyre pressure sensor, and in the drawing being the sensor marked (60) in FIG. 1. The sensor (60) includes an internally threaded tyre connection port (130) configured to threadingly and sealingly engage with the valve stem of the intended tyre. The body (135) houses therewithin the pressure transducer, microprocessor, electronic memory having program instructions and the sensor identifier, communications module, battery and any other electronics required for operability.

[0440] . The sensor (60) is of the flow-through type and therefore further comprises an externally threaded tyre inflation port (140) comprising a valve and configured to connect to the output of a tyre inflation apparatus. The thread allows for connection of protective cap (145).

[0441] . The ports (130) and (140) are in gaseous connection allowing for a tyre inflating gas to pass from port (140) to port (130) and thereafter into the tyre connected to port (130). Conversely, the tyre may be deflated by manually actuating the valve in port (140).

[0442] . FIG. 4A and FIG. 4B show a dead-end type of tyre pressure sensor in accordance with the present invention. This type of sensor lacks the inflation port and protective cap of the embodiment illustrated in FIG. 3, and accordingly must be removed to effect tyre inflation.

[0443] . The system is supplied to a purchaser having the requisite number tyre pressure sensors and with each sensor having the required wheel position indicator. A receiver / display unit having a communications module capable of pairing with the communications module of each sensor is also provided. In some cases, the purchaser will require only a set of sensors (for example, to be fitted to a new trailer) for use with an existing receiver / display unit mounted in an existing truck. In any event, the set of sensors may collocated so as to remain together until such time that an installer seeks to fit the sensors to a vehicle.

[0444] . The present invention, in certain embodiments provides advantage over the prior art in the form of wheel auto-location system for heavy-duty vehicle trailers, comprising self-pairing tyre pressure sensors with a 24-bit ID code, a predetermined numbering convention, and a self-learning mechanism for adaptive maintenance procedures.

[0445] . The use of a particular 24-bit identifier provides for efficient wheel position identification.

[0446] . To facilitate manufacture, a Sequential Numbering (SN) approach for Last Byte(LB) sensors is provided, ensuring sequential production with diverse position coverage.

[0447] . General Purpose (GP) logic for positions are encoded in the Most Significant Byte(MSB), allowing app-controlled autolearn and adaptability.

[0448] . Moreover, RSSI plausibility is implemented to facilitate the pairing of new sensors and receivers in a tyre pressure monitoring system.

[0449] . The present invention is described mainly by reference to the drawn embodiments.It will be understood that any feature described in relation to the drawn embodiments may be freely applied to any other embodiment of the invention.

[0450] . Those skilled in the art will appreciate that the invention described herein is susceptible to further variations and modifications other than those specifically described. It is understood that the invention comprises all such variations and modifications which fall within the spirit and scope of the present invention.

[0451] . Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.

Claims

CLAIMS:

1. A tyre pressure sensor connectable to a valve stem of a tyre so as to sense a pressure of a gas within the tyre, the sensor comprising a radio transmitter configured to indicate a position of a wheel on which it is installed in relation to a vehicle.

2. The tyre pressure sensor of claim 1 , wherein the radio transmitter transmits (i) a wheel position, or (ii) a sensor identifier to a receiving unit, wherein the sensor identifier correlates to a position of a wheel in relation to a vehicle.

3. The tyre pressure sensor of claim 1 or claim 2, comprising or associated with a human comprehensible wheel position indicator defining a position of a wheel in relation to a vehicle.

4. The tyre pressure sensor of any one of claims 1 to 3, wherein the wheel position indicator is displayed on or about the tyre pressure sensor, or forms a part of the tyre pressure sensor, or is completely or partially enclosed within the tyre pressure sensor.

5. The tyre pressure sensor of any one of claims 1 to 4, wherein the wheel position indicator is displayed on a tag attached to the tyre pressure sensor, or on packaging associated with the tyre pressure sensor.

6. The tyre pressure sensor of any one of claims 3 to 5, wherein the wheel position indicator is comprehensible by way of output by an electronic device in data communication with the tyre pressure sensor.

7. The tyre pressure sensor of any one of claims 3 to 6, wherein the wheel position indicator is comprehensible by visual, tactile, or audio means.

8. The tyre pressure sensor of any one of claims 2 to 7, wherein the sensor identifier is correlated with the position of a wheel position by way of a remote device in data communication with the tyre pressure sensor.

9. The tyre pressure sensor of claim 8, wherein the remote device has stored thereon a lookup table correlating the sensor identifier with a wheel position indicator.

10. The tyre pressure sensor of claim 8 or claim 9, wherein the remote device is an output device configured to output pressure information in a human-comprehensible form.

11. The tyre pressure sensor of any one of claims 3 to 10, wherein the wheel position indicator indicates the position by way of any one or more of a numeral, a letter, a graphic, an icon, a symbol, a drawing, and a sound.

12. The tyre pressure sensor of any one of claims 2 to 11, wherein the sensor identifier is a computer-readable string.

13. The tyre pressure sensor of any one of claims 2 to 12, wherein the sensor identifier is unique in relation to the identifier of other tyre pressure sensors within a set of sensors operable in relation to a single receiving unit.

14. The tyre pressure sensor of any one of claims 1 to 13 comprising an orientation indicator configured to output a variable orientation in response to the rotation of a wheel on which the tyre pressure sensor is installed.

15. The tyre pressure sensor of any one of claims 1 to 14, being of (i) the flow-through type and comprising a gas input port and a gas output port, wherein the gas input port is configured to input a tyre inflating gas and the gas output port in configured to output the tyre inflating gas into the tyre valve stem, or (ii) the dead-end type and comprising a gas input port..

16. A collocation of tyre pressure sensors, each of the tyre pressure sensors according to any one of claims 1 to 15.

17. The collocation of claim 16, wherein each of the tyre pressure sensors are tethered together or disposed within a volume.

18. The collocation of claim 17, wherein the volume is defined by a holding vessel, a transport vessel, a product package, a retail package, a transport package, a postal package, a courier package, a “click and collect” package, and a bag.

19. The collocation of any one of claims 16 to 18, wherein each sensor identifier is unique and each wheel position indicator is unique within the collocation.

20. The collocation of any one of claims 2 to 19, wherein each of the wheel position indicators together define each of the wheel positions in a wheeled apparatus.

21. The collocation of claim 20, wherein the wheeled apparatus has greater than 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 wheels.

22. The collocation of claim 20 or claim 21, wherein the wheeled apparatus is selected from: a heavy vehicle, a truck, a van, a trailer, and a caravan.

23. The collocation of any one of claims 20 to 22, wherein the wheeled apparatus is not a passenger vehicle.

24. A tyre pressure monitoring system comprising: a plurality of tyre pressure sensors each of which comprises a radio transmitter,, and a receiving unit configured to receive a radio signal encoding a sensed pressure value, the receiving unit being further configured to receive (i) a wheel location, or (ii) an identifier or (iii) a signal strength from each of the plurality of tyre pressure sensors, wherein the identifier or the signal strength or a variation in signal strength is used to identify the wheel location of one or more of the plurality of tyre pressure sensors.

25. The tyre pressure monitoring system of claim 24, wherein each of the plurality of tyre pressure sensors is according to any one of claims 1 to 15.

26. The tyre pressure monitoring system of claim 24 or claim 25, wherein the plurality of tyre pressure sensors is 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 tyre pressure sensors.

27. The tyre pressure monitoring system of any one of claims 24 to 26, wherein the receiving unit is configured to output in human comprehensible form, a wheel position and a tyre pressure value sensed by a sensor at that wheel position, as transmitted by each of the plurality of tyre pressure sensors.

28. The tyre pressure monitoring system of any one of claims 24 to 27, wherein the receiving unit is configured to correlate an identifier or a signal strength, or a signal strength variability with a wheel position.

29. The tyre pressure monitoring system of claim 28, wherein the correlation is facilitated by an electronic lookup table correlating the sensor identifier, or the signal strength, or the signal strength variability with a wheel position.

30. The tyre pressure monitoring system of any one of claims 24 to 29, wherein the receiving unit is configured to discern the wheel position by reference to the sensor identifier or the signal strength, or the signal strength variability.

31. The tyre pressure monitoring system of any one of claims 24 to 30, wherein the receiving unit is configured to store the sensor identifier, the signal strength or the signal strength variability of a signal transmitted by the radio transmitter of each of the plurality of tyre pressure sensors.

32. The tyre pressure monitoring system of claim 31, wherein the receiving unit is configured to correlate each of the saved sensor identifiers, signal strengths, or signal strength variabilities with a wheel position.

33. The tyre pressure monitoring system of any one of claims 24 to 32, wherein the tyre pressure sensor comprises an orientation indicator configured to output a point or a region in the angular rotation of a wheel on which the tyre pressure sensor is installed.

34. The tyre pressure monitoring system of any one of claims 24 to 33, wherein the signal strength is determined at a predetermined point or region in the angular rotation of a wheel on which the tyre pressure sensor is installed.

35. The tyre pressure monitoring system of any one of claims 32 to 34, wherein upon introduction of a new tyre pressure sensor, or upon reintroduction of an existing tyre pressure sensor, into the system the receiving unit by processor means: compares (i) the signal strength or the signal strength variability of a signal transmitted by the radio transmitter of the new or the reintroduced tyre pressure sensor to (ii) one or more of the stored signal strengths or signal strength variabilities, identifies a stored signal strength or signal strength variability that is the same as, or the most similar to, the signal strength or signal strength variability of a signal transmitted by the radio transmitter of the new or the reintroduced existing tyre pressure sensor, and correlates the new or the reintroduced tyre pressure sensor to the wheel position correlated with the identified stored signal strength or signal strength variability.

36. The tyre pressure monitoring system of claim 35, wherein the step of correlating comprises correlating an identifier of the new tyre pressure sensor with the wheel position correlated with the identified stored signal strength or signal strength variability.

37. The tyre pressure monitoring system of claim 35 or claim 36, wherein the step of correlating comprises maintaining an existing correlation between the identifier of the reintroduced tyre pressure sensor and a wheel position.

38. A wheeled apparatus having the system of any one of claims 24 to 37 fitted thereto, wherein each of the plurality of tyre pressure sensors is fitted to the valve stem of a tyre mounted on a wheel at the wheel position according to the sensor identifier of the respective tyre pressure sensor.

39. The wheeled apparatus of claim 38, wherein each of the plurality of tyre pressure sensors is fitted to a valve stem of a tyre mounted on a wheel at the wheel position according to the sensor identifier of the respective tyre pressure sensor.

40. The wheeled apparatus of claim 38 or claim 39, wherein each of the tyre pressure sensors comprises or is associated with a human comprehensible wheel position indicator defining a position of a wheel in relation to a vehicle, and each of the plurality of tyre pressure sensors is connected to a valve stem of a tyre mounted on a wheel at the wheel position according to the wheel position indicator of the respective tyre pressure sensor.

41. The wheeled apparatus of any one of claims 38 to 40, wherein the receiving unit is located such that a driver of the vehicle is able to comprehend an output therefrom.

42. The wheeled apparatus of claim 41, wherein the receiving unit is located in or about a driver cabin of the vehicle.

43. The wheeled apparatus of any one of claims 38 to 42 that is selected from: a heavy vehicle, a truck, a van, a trailer, and a caravan.

44. The wheeled apparatus of any one of claims 38 to 43 that is not a passenger vehicle.

45. A method of installing a tyre pressure monitoring system on a wheeled apparatus, the method comprising the steps of: providing the system of any one of claims 24 to 37,for each of the plurality of tyre pressure sensors locating a wheel of the wheeled apparatus which correlates therewith by reference to the sensor identifier or the wheel position indicator, and connecting each of the sensors to the valve stem of the tyre mounted on its correlating wheel.

46. The method of claim 45 comprising locating the receiving unit in or about a driver cabin of the wheeled apparatus.

47. A method of replacing a tyre pressure sensor of the tyre pressure monitoring system of any one of claims 24 to 37 when installed on a wheeled apparatus, the method comprising the steps of: identifying a wheel of the wheeled apparatus to which the tyre pressure sensor to be replaced is installed, providing a replacement tyre pressure sensor having a sensor identifier or a wheel position indicator that correlates to the position of the wheel, removing the tyre pressure sensor to be replaced, and installing the replacement tyre pressure sensor to the tyre on the wheel.

48. A method of automatically identifying a wheel position of a tyre pressure sensor having a radio transmitter, the method comprising the steps of: by a radio receiver unit, determining a signal strength or a variability in signal strength, correlating the determined signal strength or signal strength variability to a signal strength or signal strength variability expected or previously determined for a tyre pressure sensor installed to a wheel position.

49. The method of claim 48, wherein the signal strength is determined at a point or within a range of the angular rotation of the wheel on which the tyre pressure sensor is installed.

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