Abstract:
A multi-tire vehicle tire monitoring system includes a plurality of tire monitoring units mounted to measure at least one measured tire parameter of a respective tire on a vehicle and transmit measured tire parameter data responsive to the tire parameter measurement. The system further includes antennae for receiving the measured tire parameter data from tire monitoring units within a respectively assigned zone of tires of the vehicle, each zone encompassing a plurality of tires, and communicating the received measured tire parameter data to a data processing unit. Each antenna is fixedly mounted in an operable spatial relationship to a respective assigned zone of tires. A display may be operatively coupled to the vehicle data processing unit to visually indicate to a user a status of measured tire parameters of tires by zone.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to tire monitoring systems for vehicles and, more specifically, to tire monitoring systems for multi-wheeled vehicles such as in tractor-trailer applications. 
       SUMMARY OF THE INVENTION 
       [0002]    According to an aspect of the invention, a multi-tire vehicle tire monitoring system includes a plurality of tire monitoring units mounted to measure at least one measured tire parameter of a respective tire on a vehicle and transmit measured tire parameter data responsive to the tire parameter measurement. The system further includes antennae for receiving the measured tire parameter data from tire monitoring units within a respectively assigned zone of tires of the vehicle, each zone comprising a plurality of tires, and communicating the received measured tire parameter data to a data processing unit. Each antenna is fixedly mounted in an operable spatial relationship to a respective assigned zone of tires. A display may be operatively coupled to the vehicle data processing unit to visually indicate to a user a status of measured tire parameters of tires by zone. 
         [0003]    In a further aspect, the antennae and/or the data processing unit are mounted to a chassis of the vehicle and the display may be user activated. The tires of a vehicle such as a coupled tractor and trailer may be grouped into at least one steer tire zone and at least one drive tire zone, the antennae each receiving tire parameter data from an assigned tire zone and the display utilized to separately indicate to a user the status of measured tire parameters of tires within the steer tire zone and the drive tire zone. 
         [0004]    The vehicle system in another aspect may mount the display within the interior of a vehicle cab. The data processing unit may be a dedicated processor incorporated into the display unit or be incorporated into the vehicle electronic control unit. 
       DEFINITIONS 
       [0005]    “Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW) multiplied by  100  percent for expression as a percentage. 
         [0006]    “Asymmetric tread” means a tread that has a tread pattern not symmetrical about the center plane or equatorial plane EP of the tire. 
         [0007]    “Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire. 
         [0008]    “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. 
         [0009]    “Equatorial Centerplane (CP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of the tread. 
         [0010]    “Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure. 
         [0011]    “Groove” means an elongated void area in a tread that may extend circumferentially or laterally about the tread in a straight, curved, or zigzag manner. Circumferentially and laterally extending grooves sometimes have common portions. The “groove width” is equal to tread surface area occupied by a groove or groove portion, the width of which is in question, divided by the length of such groove or groove portion; thus, the groove width is its average width over its length. Grooves may be of varying depths in a tire. The depth of a groove may vary around the circumference of the tread, or the depth of one groove may be constant but vary from the depth of another groove in the tire. If such narrow or wide grooves are substantially reduced depth as compared to wide circumferential grooves which the interconnect, they are regarded as forming “tie bars” tending to maintain a rib-like character in tread region involved. 
         [0012]    “Inboard side” means the side of the tire nearest the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
         [0013]    “Lateral” means an axial direction. 
         [0014]    “Lateral edges” means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the lines being parallel to the equatorial centerplane. 
         [0015]    “Net contact area” means the total area of ground contacting tread elements between the lateral edges around the entire circumference of the tread divided by the gross area of the entire tread between the lateral edges. 
         [0016]    “Non-directional tread” means a tread that has no preferred direction of forward travel and is not required to be positioned on a vehicle in a specific wheel position or positions to ensure that the tread pattern is aligned with the preferred direction of travel. Conversely, a directional tread pattern has a preferred direction of travel requiring specific wheel positioning. 
         [0017]    “Outboard side” means the side of the tire farthest away from the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
         [0018]    “Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire. 
         [0019]    “Rib” means a circumferentially extending strip of rubber on the tread which is defined by at least one circumferential groove and either a second such groove or a lateral edge, the strip being laterally undivided by full-depth grooves. 
         [0020]    “Sipe” means small slots molded into the tread elements of the tire that subdivide the tread surface and improve traction, sipes are generally narrow in width and close in the tires footprint as opposed to grooves that remain open in the tire&#39;s footprint. 
         [0021]    “Tread element” or “traction element” means a rib or a block element defined by having a shape adjacent grooves. 
         [0022]    “Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0024]      FIG. 1  is a perspective view of a wheel unit component of the subject system. 
           [0025]      FIG. 2  is a perspective view of a wheel unit mounted to a wheel rim. 
           [0026]      FIG. 3  is a perspective view of a tire pressure monitoring system electronic control unit (ECU). 
           [0027]      FIG. 4  is a perspective view of an antenna unit component of the subject system. 
           [0028]      FIG. 5  is a plan view of a driver-viewed display unit employed is a tractor truck application. 
           [0029]      FIG. 6  is a schematic of a system configured pursuant to the invention. 
           [0030]      FIG. 7  is a schematic representation of a system employing a drive over reader. 
           [0031]      FIG. 8  is a perspective view of a tractor trailer deploying a trailer-based visual display unit. 
           [0032]      FIG. 9  is a schematic representation of an alternative system employing telematic transmission of data to a remote receiver. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Referring to  FIG. 1 , the subject tire pressure monitoring system for commercial truck application is configured from multiple components including one or more wheel-based sensor units  10  that measures pressure and/or temperature of a tire and transmits pressure, temperature, and wheel unit identification to an antenna unit. The sensor units  10  are of a type commercially available and are battery powered and configured having a casing  12  formed of suitably durable material and including support flanges  14  at opposite ends. 
         [0034]    The units  10  are mounted to a respective wheel rim  16  by a strap  20  that is positioned to circumscribe a central region  18  of the rim. The unit  10  may be mounted to the rim prior to mounting a tire. So mounted at region  18 , the unit  10  is exposed to the interior of the tire mounted to the rim and is operatively located to measure the temperature and air pressure within the tire cavity. The device  10  may include programmable memory into which the wheel unit identification number can be stored for subsequent access as required. 
         [0035]    A second component  22  utilized in the system is shown in  FIG. 3 . One or more tire pressure monitoring system electronic control units (ECU)  22  are configured having interface connectors  24 ,  26  that connect with circuit board(s) (not shown) within the ECU 22 . Each ECU  22  has a pair of mounting flanges  28  extending from opposite sides, each flange  28  having a centered mounting aperture  30 . The ECU is of a type commercially available and operably hosts system functions/intelligence within the system. The flanges  28  and mounting apertures  30  facilitate a chassis mounting of the ECU to a trailer chassis. 
         [0036]    An antenna unit  32  constitutes a further system component as shown in  FIG. 4 . It is contemplated that multiple antenna units  32  will be utilized in a vehicle implementation. Each antenna unit  32  mounts to a chassis by means of flanges  34  and mounting apertures  36  in a position from which to operably communicate with a respective wheel unit component  10 . Each antenna unit  32  comprises a smart radio frequency (RF) antenna/receiver of a type commercially available and connects by means of wireless transmission or hard wire transmission with an ECU  22  through connector interface  37 . 
         [0037]      FIG. 5  illustrates a display unit  38  suitable for mounting within the cab of a vehicle such as a commercial tractor. The display unit  38  has separate visual indicia for each group or zone of tires being monitored; for example as shown, the status of drive tires are communicated visually by indicator  40  and the steer tire zone is communicated by means of indicator  42 . 
         [0038]    An “on” button  44  activates the unit  38  for initial operation and a button  46  is provided to activate on demand to initiate a sensor reading of the tire status within each tire zone. The in-cab display thus provides an automatic tire identification by axle group; continually monitors tire health and warns the driver of problems. The readiness function allows the driver/maintenance to get the status of tire health with a touch of the button  46 . Telematics of data reflecting tire status and health may be used to transmit data continuously to a fleet data processor, if desired, whereby allowing tire health to be monitored continuously. 
         [0039]    The “on” button  44  may be color coded by LED illumination or other known devices to visually show a steady green light, for example, to indicate the system is working. The drive and steer indicators  40 ,  42 , respectively may be off to indicate no problem is being detected. The readiness button  46  may be depressed for maintenance operations. When the sensors within a zone (e.g. an axle) of tires detects that the axle has tires that are a preset percentage below recommended cold pressure, say, for example, ten percent, the indicator lights  40  and/or  42  may be made to emit a steady yellow light. When the tires within a zone (axle) are at a greater percentage below recommended cold pressure (e.g. 20 percent), the light emitted from indicators  40 ,  42  may change to a steady orange. Still further, the lights  40 ,  42  may be configured to blink to indicate a system malfunction in the drive or steer tire axle tires, respectively. 
         [0040]      FIG. 6  shows in schematic form one implementation of the subject invention for a commercial tractor. A tractor  50  is equipped with eight drive tires  52  in a tandem axle configuration and two steer tires  54 , respectively. A communication link  56  extends between a front-mounted antenna unit  32 B and an ECU Tire Pressure Monitor  22  and a rear-mounted antenna unit  32 A communicates with the Monitor  22  by means of communication link  58 . The ECU Tire Pressure Monitor  22  is connected via link  60  to a display unit  38  mounted within the cab of the tractor  50  so as to be visible to an operator of the unit. Each of the drive wheel units  52  has a tire equipped with a wheel unit sensor unit  10  that measures tire pressure and communicates pressure by transmission to the antenna unit  32  A which, in turn, relays the data to the ECU Monitor  22 . The ECU Monitor  22  analyzes the data and displays by, preferably, color coded actuation, tire pressure status information to the user by means of display  38  as described previously. It will be appreciated that the antenna unit  32 A services an axle zone comprising a plurality of drive wheel units  52 , each having one or more tire pressure sensor unit(s)  10 . Accordingly, a user may ascertain from display  38  by drive axle zone the pressure status of tires within such zone. 
         [0041]    Similarly, the antenna unit  32 B services an axle zone comprising a plurality of steer wheel units  54 , each having one or more tire-based pressure sensor unit(s)  10 . Information from such units is communicated to antenna unit  32 B and therefrom to the ECU Monitor  22 . A user may ascertain from display  38  by steer axle zone the pressure status of tires within such zone. The user will thus be able to discern by zone whether the tires within a zone are all properly inflated or whether one or more tires is in an under-inflated condition requiring remedial action. 
         [0042]      FIG. 7  illustrates a read station in which the tire pressure sensor units  10  may be read as a truck (either a box truck or a tractor trailer as shown in  FIG. 7 ) pass through the station. An antenna loop  62  is situated within a read station and includes electrical interconnections  54  to a receiver/transmitter  66 . The antenna loop  62  may be buried or situated on a pad within the station. One or more antenna loops  62  may be located within the station in series. The antenna loop(s)  62  are located such that the tractor trailer  48 ,  50  passes over the loop within the station and thereby allows the wheel unit sensor units  10  to transmit data to the transceiver  66 . The transceiver  66  can through wired or wireless transmission transmit such data to a processor such as computer  68 . The processor  68  can thereby accept and process data relating to tire inflation status, tire identity, and vehicle identity while the tractor trailer moves through the station. The operator of the tractor can therefore be accessing and assessing the status of tire pressure from the cab of the tractor as described previously while the data is communicated through transceiver  66  for data storage and processing by computer  68 . 
         [0043]    A visual tire status indicating display  70  may be mounted to the trailer unit to all the status of tires on the trailer  48  to be visually communicated while the trailer is connected to the tractor  50  and while the trailer  48  is disconnected. The display  70  is mounted to an external surface of the trailer  48  in a location preferably visible to the operator of the tractor  50  from the cab and from the ground such as by maintenance personnel. The display  70  in  FIG. 8  consists of an L-shaped mounting bracket  72  that attaches by suitable means to a forward corner of the trailer  48  at a height visible to the operator through the rear mirror of the tractor  50  and to a person situated along side the trailer. A second display unit  70  may be mounted to the opposite forward corner of the trailer if so desired. 
         [0044]    The bracket  72  is configured having a side panel  73  extending along a side of the trailer  48  and a forward directed front panel  74 . The panels  73 ,  74  intersect at right angles to form the bracket  72 . Secured to the front panel  74  is a display  76  comprising light emitting devices such as LED&#39;s. The display  76  may further be configured to include electronic devices that are selectively activated to emit light of different colors, depending on the status of the tires in the trailer unit. The external display  76 , being positioned on the nose portion of the trailer, is visible from the driver&#39;s rear view mirror. The display  76  visually indicates the monitored tire status and warn the driver of problems in tire inflation. An “on” button  78  may be positioned to reflect the on status of the system. A readiness function is achieved by activation of a button  80  positioned adjacent the display  76 . The readiness function allows the driver or maintenance associate to get a visual indication of the last reported tire status report with a push of the button  80 . 
         [0045]    As shown in  FIG. 9 , the ECU monitor control unit  22  may be powered by a battery  82  and is wired to the display  76 . The inflation status of tires  52  is measured by the wheel unit component  10  for each tire and transmitted to the antenna unit  32  assigned to each tire zone. From the antenna  32 C the data is transmitted to the ECU control unit  22  and may, if desired, be communicated by telematics to a remote data processing unit  68 . A record of tire inflation status and tire identification may thereby be preserved for fleet management. In addition, a visual indication of the status of the tires may be transmitted to the display  76  from the ECU unit  22  to indicate tire status to a driver and/or ground maintenance personnel. 
         [0046]    The display  76  and on button  78  may be configured to emit light of different colors to indicate status. For example, without limitation intended, the “on” button  78  may emit a steady green light to indicate the system is working and no light if the system is not. No light emitted from display  76  may indicate the absence of a problem with the tires of the trailer unit. A yellow light emitted from the display may indicate that one or more tires is a preset percentage (e.g. 10 percent) below recommended cold tire air pressure. An orange display light may indicate that one or more tires within a zone is a preset greater percentage (e.g. 20 percent) below recommend pressure. A blinking display  76  or “on” button  78  may indicate a malfunction on the trailer or within the trailer monitoring system. 
         [0047]    The reported pressures of tires within each tire zone are preferably temperature compensated for improved accuracy of the tire inflation status measurement. The function of the trailer monitoring system is coupled from the ECU  22  to the display  38  within the cab of the tractor by telematic transmission to allow the driver to visually monitor trailer tire zone status with the monitoring of tractor tire zone status. 
         [0048]    Depressing the readiness button  46  may initiate a system display of the status of tires based on data collected within the time period in which the tractor or trailer is parked. The data received from the sensor(s) within each tire may be temperature compensated to ensure the accuracy and legitimacy of warnings conveyed by the light signals emitted from indicators  40 ,  42 . 
         [0049]    The system described previously consists of pressure/temperature sensors, antennas, an electronic control unit (ECU) and a telematics unit. Typically a sensor module will be assigned and operatively mounted for each tire. An antenna is assigned for each region or zone on the vehicle such as drive, steer, and trailer tires. Preferably there will be at least two ECU&#39;s and two telematics units, one each for the tractor and one each for the trailer. 
         [0050]    The pressure/temperature measurements are transferred wirelessly from the wheel unit sensor to the antenna and on to the ECU and then to the telematics unit. The information is then sent to the fleet operator or other maintenance facility. Normally this information would not be displayed for the driver or local maintenance personnel but it may be done if so desired. The tire information provides local information for the driver or local maintenance personnel. For this, the tractor trailer tires are grouped into three zones. The first two zones are steer and drive for the tractor and the third zone is the trailer tires. 
         [0051]    The tractor display is mounted on the interior dash and includes three indicators. One is to indicate that the system is on and functioning properly. The other two indicators are for the inflation status for the tires in the steer and drive zones. The display for the trailer is mounted on the front corner of the trailer so that it is visible in the driver&#39;s rearview mirror. Two indicators are present for the trailer display; one for the system status and the other for the inflation status of the trailer tires. Each display also has a readiness button that can be used to query the last known inflation status for the tires in the zones monitored by that display unit. This allows for a check on the tire status for the trailer before it is loaded and for the tractor before it leaves the terminal. 
         [0052]    In one embodiment, a microcontroller is within the display rather than in the ECU. An advantage of placing local intelligence in the display module is that display behavior can be changed without reprogramming the system ECU. A communications port may be added to the display and use its local intelligence to filter and format data communication to telematic or other systems. In this manner, specific interfaces for drivers and telematics solutions can be delivered without changing system ECU programming. 
         [0053]    The system thus monitors the condition of the tires on the tractor unit as well as the trailer unit and conveys measured data to a fleet operator or maintenance facility. The information is further used to provide the operator and local maintenance personnel with tire status by means of a display within the cab of the tractor and a display mounted to the trailer. Measured tire parameters may include monitoring the pressure or temperature within each tire utilizing a pressure/temperature sensor mounted to the tire or wheel rim. One or more sensor module is employed for each tire. The pressure/temperature measurements from each tire are transferred wirelessly from the wheel unit sensor to an antenna and on to a processing unit such as the vehicle electronic control unit (ECU) and/or a microcontroller within each display unit. From the ECU, the data is transferred to a telematics unit. 
         [0054]    The system deploys a sensor module for a group or region of tires. A separate first display within the cab of the tractor communicates the status of tractor drive and steer tires to the operator while a second display unit mounted to the trailer communicates the status of trailer zone tires to the operator visually by means of a rearview mirror. The sensor(s) from each tire within a group or region transmits data. The grouping of tires may be, for example, the tires of the tractor and a second or third group for the trailer. An under inflated tire on either the tractor or the trailer may be identified and a warning provided to the driver through first and second display units. Such information allows for corrective action to be taken before it becomes a safety issue. Running with properly inflated tires increases fuel economy and decreases treadwear. Properly inflated tires provide better vehicle handling and increased tire durability. 
         [0055]    The system eliminates the need to conduct a teaching procedure that registers, and registers with each tractor/trailer change, each sensor and its wheel position from a tractor and trailer in the ECU. Since the status of the trailer tires is communicated by a self-contained display mounted to the trailer, any operator of a tractor coupled to that trailer can ascertain the status of the trailer tires by looking at the display in a rearview mirror. The system eliminates the need to re-register each tire if any tires are replaced or their positions rotated and avoids system failure resulting in a failure to properly identify each tire. The system in avoiding the need for repetitive teaching procedures to teach the system which tires are in use and where; saves time and avoids the need for additional equipment. In so doing, the system improves efficiency and reduces costs associated with the operation of a commercial trucking fleet. 
         [0056]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.