Patent Application
20110043343
The invention relates generally to tire pressure monitoring systems for vehicles and, more specifically, to tire pressure monitoring and display systems for multi-wheeled vehicles such as in tractor-trailer systems.
In one aspect of the invention, a tandem tractor and trailer system includes a tractor having a cab and one or more trailers, each having multiple wheel units, each wheel unit having a mounted tire and a tire pressure measuring device. A first display unit mounts within the cab of the tractor and an additional display unit(s) to the exterior of the trailer(s), each display unit operating to communicate to an operator of the tractor a visible indicia of tractor and trailer tire inflation pressure status, respectively, based upon pressure measurements of the tractor and trailer tire pressure measuring devices, respectively.
In another aspect, the second display unit mounts to a forward end of the trailer at a mounting location operatively visible by differentiated colored light emission through a rear view mirror to the operator of the tractor during operation of the tractor and the trailer.
According to a further aspect, the system further includes one or more receivers operatively mounted to the tractor and trailer to receive measured tire inflation pressure data from the tractor and trailer tire pressure measuring devices, respectively, and communicate the received measured tire inflation pressure data by hard wire or wireless transmission to a commonly shared or, alternatively, local data processing unit(s), as preferred in a given application. The data processing unit(s) may be based within each display unit or be configured as part of a vehicle centered electronic control unit and may include an operator-controlled reset function to re-process the tractor and/or trailer tire pressure data on demand.
“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.
“Asymmetric tread” means a tread that has a tread pattern not symmetrical about the center plane or equatorial plane EP of the tire.
“Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire.
“Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction.
“Equatorial Centerplane (CP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of the tread.
“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.
“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.
“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.
“Lateral” means an axial direction.
“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.
“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.
“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.
“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.
“Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire.
“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.
“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's footprint.
“Tread element” or “traction element” means a rib or a block element defined by having a shape adjacent grooves.
“Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread.
The invention will be described by way of example and with reference to the accompanying drawings in which:
Referring to
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.
A second component 22 utilized in the system is shown in
An antenna unit 32 constitutes a further system component as shown in
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.
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.
Similarly, the antenna unit 32B 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 32B 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.
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
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'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'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.
As shown in
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.
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.
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.
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's and two telematics units, one each for the tractor and one each for the trailer.
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.
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'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.
In one embodiment, a microcontroller is a component of the display unit rather than a coupled tractor and trailer based 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.
The system thus may monitor 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 component of each display unit. From the ECU, the data is transferred to a telematics unit. A reset button may be deployed as a component of each display unit, whereby an operator may initiate a recalculation and display of tractor and trailer tire inflation status before and after loading a trailer. The reset button may further be used to initiate a recalculation and display as the tractor and trailer tandem leaves a read station. Departure data can then be uploaded to a read station data processor by wireless transmission and thereby be maintained as a record of tire inflation status when the tandem unit departed from the terminal.
The system preferably 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.
The system configured to incorporate a microprocessor component within each of the tractor and trailer display units 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. 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.
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.
