Backup for tire pressure monitoring system

Abstract

The present disclosure provides a backup for a tire pressure monitoring system. A computer includes a processor and a memory, and the memory stores instructions executable by the processor to: in response to a speed at which a vehicle travels exceeding a vehicle speed threshold, determine a difference between wheel speeds of different wheels of the vehicle; and in response to the difference exceeding a difference threshold, outputting a message indicative of a low pressure of a tire of one of the wheels.

Description

Technical Field

[0001] This disclosure relates to tire pressure monitoring systems. Background Technology

[0002] A tire pressure monitoring system (TPMS) is a system used to monitor the air pressure of a vehicle's tires. When the TPMS detects that one of the vehicle's tires is below a threshold pressure, an indicator light on the dashboard illuminates to notify the driver about the tire pressure. TPS uses pressure sensors mounted on the inner or outer surface of each tire. Pressure sensors mounted inside the tire communicate using short-range wireless signals. Summary of the Invention

[0003] This disclosure provides a technique for functional redundancy in a tire pressure monitoring system (TPMS) for a vehicle. In other words, the task of monitoring tire pressure can still be performed even if the TPMS is inactive. If the TPMS is inactive, the vehicle's computer is programmed to determine the difference between the wheel speeds of the different wheels of the vehicle in response to the vehicle's speed exceeding a vehicle speed threshold; and in response to the difference exceeding a difference threshold, output a message indicating low pressure in one of the tires. If one tire rotates faster than the others, that tire has a smaller diameter and may therefore be underinflated. Wheel speeds can be reported by wheel speed sensors on each wheel. The measurements from the wheel speed sensors may experience large fluctuations at lower speeds. The use of a vehicle speed threshold helps to ensure that the difference between wheel speeds is accurate enough for monitoring tire pressure.

[0004] A computer includes a processor and a memory, and the memory stores instructions executable by the processor to: determine a difference between the wheel rotation speeds of different wheels of the vehicle in response to the vehicle's speed exceeding a vehicle speed threshold; and output a message indicating low tire pressure of one of the wheels in response to the difference exceeding the difference threshold.

[0005] In one example, the instructions may further include instructions for performing the following operation: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's steering angle being within a steering angle range. In another example, the steering angle range may include a straight-line forward steering angle.

[0006] In one example, the instructions may also include instructions to determine the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's tire pressure monitoring system being inactive.

[0007] In one example, the vehicle may include a corresponding tire pressure monitoring system for each tire, and the instructions may also include instructions to determine the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and at least one of the tire pressure monitoring systems being inactive.

[0008] In one example, the instructions may also include instructions for performing the following operation: in response to the speed exceeding the vehicle speed threshold for at least a certain time threshold, determining the difference between the wheel rotation speeds.

[0009] In one example, the instructions may also include instructions for performing the following: in response to the speed exceeding the vehicle speed threshold and the vehicle's current operating mode being a first operating mode, determining the difference between the wheel rotation speeds.

[0010] In one example, the difference can be between the fastest wheel speed and the slowest wheel speed. In another example, the fastest wheel speed and the slowest wheel speed can occur simultaneously.

[0011] In another example, the difference can be expressed as a proportion of the slowest wheel speed.

[0012] In one example, the instructions may further include instructions to set a flag in the memory in response to the difference exceeding the difference threshold. In another example, the instructions may further include instructions to output a message indicating low tire pressure in response to the vehicle starting with the flag set.

[0013] In another example, the instructions may also include instructions to remove the flag in response to the difference being less than the difference threshold for at least a certain period of time after the flag is set.

[0014] One method includes: determining a difference between wheel rotation speeds of different wheels of the vehicle in response to the vehicle traveling at a speed exceeding a vehicle speed threshold; and outputting a message indicating low tire pressure of one of the wheels in response to the difference exceeding the difference threshold.

[0015] In one example, the method may further include: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's steering angle being within a steering angle range.

[0016] In one example, the method may further include: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's tire pressure monitoring system being inactive.

[0017] In one example, the vehicle may include a corresponding tire pressure monitoring system for each wheel, and the method may further include: determining the difference between the wheel rotational speeds in response to the speed exceeding the vehicle speed threshold and at least one of the tire pressure monitoring systems being inactive.

[0018] In one example, the method may further include: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold for at least a certain time threshold.

[0019] In one example, the method may further include: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's current operating mode being a first operating mode.

[0020] In one example, the difference could be between the fastest wheel speed and the slowest wheel speed. Attached Figure Description

[0021] Figure 1 This is a schematic top view of an exemplary vehicle.

[0022] Figure 2 This is a flowchart of an exemplary process for determining the tire pressure of a vehicle. Detailed Implementation

[0023] Referring to the accompanying drawings, wherein the same reference numerals denote the same parts throughout several views, computer 105 includes a processor and a memory, and the memory stores instructions that can be executed by the processor to: determine the difference between the wheel rotation speeds of different wheels 110 of vehicle 100 in response to vehicle 100 traveling at a speed exceeding a vehicle speed threshold; and output a message indicating low pressure in the tire 115 of one of the wheels 110 in response to the difference exceeding the difference threshold.

[0024] refer to Figure 1 Vehicle 100 can be any passenger or commercial vehicle, such as a sedan, truck, SUV, crossover, van, minivan, taxi, bus, etc. Vehicle 100 may include wheels 110, tires 115, computer 105, communication network 120, tire pressure monitoring system (TPMS) 125, wheel speed sensor 130, speedometer 135, steering angle sensor 140, and user interface 145.

[0025] Computer 105 is a microprocessor-based computing device, such as a general-purpose computing device (including a processor and memory, electronic controller, etc.), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or a combination thereof. Typically, hardware description languages ​​such as VHDL (VHSIC (Very High Speed ​​Integrated Circuit) Hardware Description Language) are used in electronic design to describe digital and mixed-signal systems such as FPGAs and ASICs. For example, an ASIC is manufactured based on VHDL programming provided before manufacturing, while the logic components inside an FPGA can be configured based on VHDL programming (e.g., stored in memory electrically connected to the FPGA circuitry). Therefore, computer 105 may include a processor, memory, etc. The memory of computer 105 may include media for storing instructions executable by the processor and for electronically storing data and / or databases, and / or computer 105 may include structures such as those providing programming capabilities. Computer 105 may be multiple computers interconnected.

[0026] Computer 105 can send and receive data via communication network 120. Communication network 120 can be a controller area network (CAN) bus, Ethernet, WiFi, local area network (LIN), on-board diagnostic connector (OBD-II), and / or any other wired or wireless communication network. Computer 105 can be communicatively connected to TPMS 125, wheel speed sensor 130, speedometer 135, steering angle sensor 140, user interface 145, and other components via communication network 120.

[0027] Vehicle 100 includes a plurality of wheels 110, typically four wheels 110. Each wheel 110 is rotatable relative to the body 150 of vehicle 100. Wheels 110 are radially symmetrical and include two radially symmetrical flanges (not shown) for mounting tires 115. Wheels 110 may be formed of a non-flexible material, such as a metal (e.g., steel or aluminum).

[0028] Vehicle 100 includes tires 115 mounted on each wheel 110. Each tire 115 is an inflatable ring mounted to the corresponding wheel 110. Tires 115 provide shock absorption and traction. Tires 115 and wheels 110 define annular air chambers that can be filled with a compressible expansion medium, such as air. The air chambers have annular shapes. Tires 115 may be formed of synthetic or natural rubber, or other elastic materials that provide sufficient elasticity, durability, and grip. Tires 115 may also include cords (not shown) extending through the elastic material and / or compounds added to the elastic material.

[0029] Vehicle 100 includes a corresponding TPMS 125 for each tire 115. TPMS 125 may be a direct TPMS sensor (i.e., a pressure sensor). Each TPMS 125 may be positioned to monitor the pressure of a corresponding inflation chamber defined by the corresponding tire 115. TPMS 125 may communicate with communication network 120 and computer 105 using wireless short-range signals.

[0030] Vehicle 100 includes a corresponding wheel speed sensor 130 for each wheel 110. Each wheel speed sensor 130 can use a magnetic field detector to count interruptions in the magnetic field via a ferromagnetic toothed induction ring (also called a speed pulse wheel) disposed on the wheel 110. The wheel speed sensor 130 can be a passive sensor comprising a ferromagnetic rod having a permanent magnet at one end and being wound in a wire. Rotation of the induction ring induces a current in the wire, which serves as the output of the wheel speed sensor 130. Alternatively, the wheel speed sensor 130 can be an active sensor, which also includes a signal conditioning circuitry system for encoding the output. The output of each wheel speed sensor 130 is a periodic wave (e.g., a sine wave or a square wave) from which the number of revolutions of the wheel 110 can be counted.

[0031] Speedometer 135 can be any sensor suitable for measuring the speed of vehicle 100, such as a known mechanical or eddy current speedometer, or a vehicle speed sensor. The vehicle speed sensor can use a magnetic field detector to count interruptions in the magnetic field via a toothed metal disc positioned on the drive shaft of vehicle 100. Alternatively, wheel speed sensors 130 can also be used as speedometer 135. For example, the speed of vehicle 100 can be derived from the average wheel speed.

[0032] Steering angle sensor 140 detects the steering angle of vehicle 100. The steering angle is the angle formed by the direction of rotation of the front wheels 110 and the longitudinal axis of vehicle 100. Steering angle sensor 140 may be a position sensor positioned to detect the orientation of steering wheel 155 of vehicle 100. For example, steering angle sensor 140 may be mounted to steering column (not shown). Steering angle sensor 140 may be, for example, a Hall effect sensor, a rotary encoder, etc. The steering wheel angle reported by steering angle sensor 140 can be converted into a steering angle based on the known steering ratio of vehicle 100.

[0033] User interface 145 presents and receives information to and from the operator of vehicle 100. User interface 145 may be located, for example, on a dashboard in the passenger compartment 160 of vehicle 100, or anywhere easily visible to the operator. User interface 145 may include dials, digital readout devices, screens, speakers, etc., for providing information to the operator, such as known human-machine interface (HMI) elements. User interface 145 may include buttons, knobs, keypads, microphones, etc., for receiving information from the operator.

[0034] In general, computer 105 is programmed to determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the satisfaction of multiple conditions. These conditions may include at least one TPMS 125 being inactive, the vehicle 100 traveling at a speed exceeding a vehicle speed threshold, the vehicle 100's steering angle being within a steering angle range, and / or one or more of the vehicle 100's current operating modes being pre-defined operating modes, as described below in sequence. In response to the satisfaction of all conditions, computer 105 uses wheel rotation speed to determine whether any of the tires 115 has low pressure, as described below. In response to the non-satiation of at least one of the conditions, computer 105 may avoid using wheel rotation speed to determine whether any of the tires 115 has low pressure. In this case, computer 105 may use data from TPMS 125 (if active) to determine whether any of the tires 115 has low pressure, or computer 105 may avoid determining whether any of the tires 115 has low pressure.

[0035] Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to TPMS 125 being inactive (e.g., in response to at least one of TPMS 125 being inactive). For example, computer 105 can determine that one of the TPMS 125 is inactive by receiving a message indicating that TPMS 125 is inactive (e.g., a Diagnostic Trouble Code (DTC)). As another example, computer 105 can determine that TPMS 125 is inactive in response to not receiving data from TPMS 125 for at least a time threshold (which will be referred to as the first time threshold, since other time thresholds are discussed below). The first time threshold can be selected to be longer than the rate at which TPMS 125 transmits data. If active, TPMS 125 can provide a more accurate determination of whether the tires 115 have low pressure.

[0036] Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the vehicle 100 traveling at a speed exceeding a vehicle speed threshold. Computer 105 can receive speed from speedometer 135. The vehicle speed threshold can be selected to be high enough to provide accurate results from wheel rotation speed sensor 130, and low enough to be exceeded during typical driving of vehicle 100 (e.g., 15 mph). For example, computer 105 can determine whether any of the tires 115 has low pressure in response to the speed exceeding the vehicle speed threshold for at least a second time threshold. The second time threshold can be selected to be long enough to average fluctuations in wheel rotation speed reported by wheel rotation speed sensor 130, thereby improving accuracy.

[0037] Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the steering angle of vehicle 100 being within a steering angle range. Computer 105 can receive the steering angle from steering angle sensor 140. The steering angle range can be selected to cover typical variations in steering angle when vehicle 100 is traveling straight. Therefore, the steering angle range includes the straight-ahead steering angle (i.e., the steering angle that occurs when the current wheel 110 is oriented parallel to the longitudinal axis of vehicle 100). For example, the steering angle range could be from –15° to +15°, where 0° is the straight-ahead steering angle. The use of the steering angle range ensures that the wheel 110 on one side of vehicle 100 does not cover more ground (and therefore rotate faster) than the wheel 110 on the other side.

[0038] Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the current operating mode of vehicle 100 being a first operating mode. For the purposes of this disclosure, an "operating mode" is defined as data or datasets indicating how one or more components of vehicle 100 operate. Vehicle 100 may have multiple current operating modes at any given time. Each of the current operating modes can be selected or determined from a set of stored operating modes (e.g., the current operating mode of a component can be selected from a first operating mode, a second operating mode, and a third operating mode). For example, an operating mode may indicate whether the traction control system is engaged, so the current operating mode may be "traction control system engaged" or "traction control system disengaged". Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the current operating mode being "traction control system disengaged" rather than in response to the current operating mode being "traction control system engaged". As another example, an operating mode may indicate whether the ignition is on, so the current operating mode may be "on", "off", or "accessory power". Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the current operating mode being "on" rather than in response to the current operating mode being "off" or "accessory power". For example, the current operating mode could be factory mode (used when vehicle 100 is being assembled), transport mode (used when vehicle 100 is being transported to its destination), or operator mode (used for typical operator driving). Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the current operating mode being operator mode rather than in response to the current operating mode being factory mode or transport mode. For example, the operating mode could indicate whether the parking brake is on or off. Computer 105 can determine whether any of the tires 115 has low pressure based on wheel rotation speed in response to the current operating mode being parking brake off rather than in response to the current operating mode being parking brake on. Using the current operating mode ensures that vehicle 100 is not in a current operating mode that could lead to a false low pressure alarm.

[0039] In response to all conditions being met, computer 105 determines whether any of the tires 115 has low pressure based on wheel rotation speed. As a general overview, computer 105 determines whether the difference between the wheel rotation speeds of the different wheels 110 exceeds a difference threshold. If so, one of the tires 115 is considered to have low pressure, and computer 105 may set a flag indicating low pressure in tire 115 in memory and output a message indicating low pressure in tire 115.

[0040] Computer 105 determines the difference between the wheel speeds of different wheels 110 of vehicle 100. This difference can be between the fastest and slowest wheel speeds. The fastest and slowest wheel speeds can occur simultaneously. In other words, within time... t The fastest wheel speed at the location oh 快 ( t ) can be in time t The maximum value of the four wheel speeds of the corresponding wheel 110 reported (i.e., oh 快 ( t ) = max( oh 1( t ), oh 2( t ), oh 3( t ), oh 4( t In time t The slowest wheel speed oh 慢 ( t ) can be in time t The minimum of the four wheel speeds of the corresponding wheel 110 reported (i.e., oh 慢 ( t ) =min( oh 1( t ), oh 2( t ), oh 3( t ), oh 4( t Using the fastest and slowest wheel speeds ensures the widest possible distribution and thus detects most low tire pressure situations (e.g., including one, two, or three tires with low pressure 115). Difference Δ oh ( t This can be expressed as the proportion of the slowest wheel speed, such as in the following expression: Standardizing the difference by using the slowest wheel speed allows the difference in wheel speeds to be comparable across different vehicle speeds.

[0041] Computer 105 determines the difference Δ oh ( t Does it exceed the difference threshold? oh th (that is, Δ) oh ( t )> oh thThe difference threshold can be a preset value stored in the memory of computer 105. The difference threshold can be selected to indicate that the pressure of tire 115 with the slowest wheel speed is lower than the recommended tire pressure of tire 115. In response to the difference exceeding the difference threshold, computer 105 can set a flag in memory and / or output a message indicating low pressure of tire 115.

[0042] In response to a difference exceeding a threshold, computer 105 may set a flag in memory indicating low pressure in tire 115. For example, the flag could be a first value of a binary variable. The first value of the binary variable (e.g., 1) indicates that at least one of tires 115 has low pressure, and a second value of the binary variable (e.g., 0) indicates that none of tires 115 has low pressure. As another example, the flag could be a Diagnostic Trouble Code (DTC), which can be formatted according to standards such as On-Board Diagnostics II (OBD-II). According to OBD-II, a DTC is formatted as a letter followed by four numbers, a combination that can identify a specific problem with vehicle 100, such as a fault associated with a vehicle component.

[0043] In response to a difference exceeding a difference threshold, computer 105 may output a message indicating low tire pressure in tire 115. For example, computer 105 may output the message in response to a setting flag (which occurs in response to a difference exceeding a difference threshold). Computer 105 may output the message by actuating user interface 145. Computer 105 may actuate user interface 145 to illuminate a light on the dashboard of vehicle 100. The light may be a light specifically for low tire pressure. Alternatively or additionally, computer 105 may actuate user interface 145 to emit a sound, such as a bell, through a speaker on user interface 145. Alternatively or additionally, computer 105 may actuate user interface 145 to display a message on the screen of user interface 145. The message may state that one of the tires 115 has low pressure.

[0044] The indicator can persist in memory throughout the entire ignition cycle of vehicle 100. For example, when vehicle 100 is turned off and then started, the binary variable can retain its value, or the DTC can retain its setting. Computer 105 can be programmed to output a message indicating low tire pressure 115 in response to vehicle 100 starting with the indicator set. Thus, the operator can be alerted to low pressure until the indicator is removed.

[0045] Computer 105 can be programmed to remove the flag in response to the difference being less than the difference threshold for at least a third time threshold after the flag is set. The third time threshold can be selected as longer than the random fluctuation of tire pressure. The third time threshold can be the same as or different from a second time threshold. Computer 105 can determine that the difference is less than the difference threshold for at least a third time threshold after the flag is set (i.e., for a period from...). t 标志 arrive t 标志 + T of t Δ oh ( t )< oh th If true, among which t 标志 It is the time when the flag is set, and T (This is the third time threshold). Computer 105 can remove the flag, for example, by setting a binary variable to a second value or removing the DTC. Computer 105 can also remove the flag in response to TPMS 125 being active and indicating that tire 115 does not have low pressure.

[0046] Figure 2 This is a flowchart illustrating an exemplary process 200 for monitoring low tire pressure 115. The memory of computer 105 stores executable instructions for performing the steps of process 200, and / or can be programmed in a structure such as those mentioned above. As a general overview of process 200, computer 105 receives data. If conditions are met (i.e., at least one of TPMS 125 is inactive, the current operating mode is in a corresponding first operating mode, the steering angle is within the steering angle range, and the speed of vehicle 100 exceeds a vehicle speed threshold for at least a second time threshold), computer 105 determines the difference between wheel speeds. In response to the difference exceeding the difference threshold, computer 105 sets a flag and outputs a message indicating low tire pressure 115. Once the flag is set, computer 105 removes the flag in response to the difference being less than the difference threshold for at least a third time threshold after the flag is set.

[0047] Process 200 begins in box 205, where computer 105 receives data indicating the current operating mode from TPMS 125 (if active), wheel speed sensor 130, speedometer 135, steering angle sensor 140, and other components.

[0048] Next, in decision box 210, computer 105 determines whether TPMS 125 is active, as described above. In response to TPMS 125 being active, process 200 ends. In response to at least one TPMS 125 being inactive, process 200 proceeds to decision box 215.

[0049] In decision box 215, computer 105 determines whether the current operating mode of vehicle 100 is in the corresponding first operating mode, as described above. In response to at least one current operating mode not being in the corresponding first operating mode, process 200 ends. In response to the current operating mode being in the corresponding first operating mode, process 200 proceeds to decision box 220.

[0050] In decision block 220, computer 105 determines whether the steering angle is within the steering angle range, as described above. If the steering angle is outside the steering angle range, process 200 ends. If the steering angle is within the steering angle range, process 200 proceeds to decision block 225.

[0051] In decision box 225, computer 105 determines whether the speed of vehicle 100 exceeds a vehicle speed threshold, as described above. In response to a speed below the vehicle speed threshold, process 200 ends. In response to a speed exceeding the vehicle speed threshold, process 200 proceeds to decision box 230.

[0052] In decision box 230, computer 105 determines whether the speed has exceeded a vehicle speed threshold for at least a second time threshold. In response to the speed exceeding the vehicle speed threshold for at least a second time threshold, process 200 returns to box 205 to continue receiving data for a longer period. In response to the speed exceeding the vehicle speed threshold for at least a second time threshold, process 200 proceeds to box 235.

[0053] At box 235, computer 105 determines the difference between the wheel speeds of different wheels 110 of vehicle 100, as described above.

[0054] Next, in decision box 240, computer 105 determines whether the difference exceeds a difference threshold, as described above. If the difference is below the difference threshold, process 200 ends. If the difference exceeds the difference threshold, process 200 proceeds to decision box 245.

[0055] In box 245, computer 105 sets a flag and outputs a message indicating low pressure in tire 115, as described above.

[0056] Next, in decision box 250, computer 105 re-determines the difference and determines whether the difference is below a difference threshold for at least a third time threshold, as described above. In response to the difference exceeding the difference threshold or being below the difference threshold for at least a third time threshold, process 200 remains at decision box 250 to continue checking the difference against the difference threshold. In response to the difference being below the difference threshold for at least a third time threshold, process 200 proceeds to box 255.

[0057] In box 255, computer 105 removes the flag, as described above. After box 255, process 200 ends.

[0058] Generally, the described computing system and / or device may employ any of a variety of computer operating systems, including, but not limited to, the following versions and / or types: Ford Sync® applications; AppLink / Smart Device Link middleware; Microsoft Automotive® operating system; Microsoft Windows® operating system; Unix operating system (e.g., Solaris® operating system released by Oracle Corporation of Redwood Coast, California); AIX UNIX operating system released by International Business Machines Corporation of Armonk, New York; Linux operating system; Mac OSX and iOS operating systems released by Apple Inc. of Cupertino, California; BlackBerry operating system released by BlackBerry Ltd. of Waterloo, Canada; and Android operating system developed by Google and the Open Handset Alliance; or the QNX® CAR infotainment platform provided by QNX Software Systems, Inc. Examples of computing devices include, but are not limited to, in-vehicle computers, computer workstations, servers, desktop computers, laptops, notebook computers, or handheld computers, or any other computing system and / or device.

[0059] Computing devices typically include computer-executable instructions, which can be executed by one or more computing devices such as those listed above. Computer-executable instructions can be compiled or interpreted from computer programs created using a variety of programming languages ​​and / or technologies, which, individually or in combination, include, but are not limited to, Java™, C, C++, Matlab, Simulink, Stateflow, Visual Basic, JavaScript, Python, Perl, HTML, etc. Some of these applications can be compiled and executed on virtual machines such as the Java Virtual Machine, the Dalvik Virtual Machine, etc. Generally, a processor (e.g., a microprocessor) receives instructions (e.g., from memory, computer-readable media, etc.) and executes those instructions to perform one or more processes, including one or more processes described herein. Such instructions and other data can be stored and transferred using a variety of computer-readable media. Files in a computing device are typically collections of data stored on computer-readable media such as storage media, random access memory, etc.

[0060] Computer-readable media (also known as processor-readable media) include any non-transitory (e.g., tangible) medium that contributes to providing data (e.g., instructions) that can be read by a computer (e.g., by the computer's processor). Such media can take many forms, including but not limited to non-volatile and volatile media. Instructions can be transmitted via one or more transmission media, including optical fibers, wires, wireless communications, and internals that constitute a system bus coupled to the computer's processor. Common forms of computer-readable media include, for example, RAM, PROM, EPROM, flash EEPROM, any other memory chip or magnetic tape, or any other medium from which a computer can read.

[0061] The databases, data repositories, or other data stores described herein can include various mechanisms for storing, accessing / retrieving various types of data, including hierarchical databases, file sets in file systems, application databases in proprietary formats, relational database management systems (RDBMS), non-relational databases (NoSQL), graph databases (GDB), and so on. Each such data store is typically contained within a computing device employing a computer operating system such as those mentioned above, and is accessed via a network in any one or more of various ways. File systems can be accessed from the computer operating system and can include files stored in various formats. In addition to languages ​​used to create, store, edit, and execute the stored programs (such as PL / SQL as described above), RDBMS typically employs Structured Query Language (SQL).

[0062] In some examples, system elements may be implemented as computer-readable instructions (e.g., software) stored on one or more computing devices (e.g., servers, personal computers, etc.) and on computer-readable media (e.g., disks, storage, etc.) associated therewith. Computer program products may include such instructions stored on computer-readable media for performing the functions described herein.

[0063] In the accompanying drawings, the same reference numerals indicate the same elements. Furthermore, some or all of these elements may be changed. Regarding the media, processes, systems, methods, inspirations, etc., described herein, it should be understood that although the steps of such processes, etc., are described as occurring in a certain ordered order, such processes can be practiced by performing the steps in a different order than that described herein. It should also be understood that some steps may be performed simultaneously, other steps may be added, or some steps described herein may be omitted.

[0064] This disclosure has been described in an illustrative manner, and it should be understood that the terms used are intended to be descriptive in nature, not restrictive. The use of terms such as “in response to,” “after determining,” etc., indicates a causal relationship, not just a temporal one. Terms such as “front,” “forward,” “longitudinal,” “rear,” “rearward,” “left,” “right,” “lateral,” “upward,” “downward,” and “vertical” are understood in relation to vehicle 100. The adjectives “first,” “second,” and “third” are used throughout this document as identifiers and are not intended to indicate importance, order, or quantity. In light of the foregoing teachings, many modifications and variations of this disclosure are possible, and this disclosure may be practiced in ways other than those specifically described.

[0065] According to the present invention, a computer is provided having a processor and a memory, the memory storing instructions executable by the processor to: determine a difference between the wheel rotation speeds of different wheels of the vehicle in response to the vehicle's speed exceeding a vehicle speed threshold; and output a message indicating low tire pressure of one of the wheels in response to the difference exceeding the difference threshold.

[0066] According to one embodiment, the instructions further include instructions for performing the following operation: in response to the speed exceeding the vehicle speed threshold and the vehicle's steering angle being within the steering angle range, determining the difference between the wheel rotation speeds.

[0067] According to one embodiment, the steering angle range includes the straight-line forward steering angle.

[0068] According to one embodiment, the instructions further include instructions for performing the following operation: in response to the speed exceeding the vehicle speed threshold and the vehicle's tire pressure monitoring system being inactive, determining the difference between the wheel rotation speeds.

[0069] According to one embodiment, the vehicle includes a corresponding tire pressure monitoring system for each tire; and the instructions further include instructions for performing the following operation: in response to the speed exceeding the vehicle speed threshold and at least one of the tire pressure monitoring systems being inactive, determining the difference between the wheel rotation speeds.

[0070] According to one embodiment, the instructions further include instructions for performing the following operation: in response to the speed exceeding the vehicle speed threshold for at least a certain time threshold, determining the difference between the wheel rotation speeds.

[0071] According to one embodiment, the instruction can also be used as an instruction to perform the following operation: in response to the speed exceeding the vehicle speed threshold and the current operating mode of the vehicle being a first operating mode, determining the difference between the wheel rotation speeds.

[0072] According to one embodiment, the difference is between the fastest wheel speed and the slowest wheel speed.

[0073] According to one embodiment, the fastest wheel speed and the slowest wheel speed occur simultaneously.

[0074] According to one embodiment, the difference is represented as a proportion of the slowest wheel speed.

[0075] According to one embodiment, the instructions further include instructions for performing the following operation: setting a flag in the memory in response to the difference exceeding the difference threshold.

[0076] According to one embodiment, the instructions further include instructions for performing the following operation: in response to the vehicle starting with the flag set, outputting the message indicating low tire pressure.

[0077] According to one embodiment, the instructions further include instructions for performing the following operation: removing the flag in response to the difference being less than the difference threshold for at least a certain period of time after the flag is set.

[0078] According to the present invention, a method includes: determining a difference between wheel rotation speeds of different wheels of the vehicle in response to the vehicle traveling at a speed exceeding a vehicle speed threshold; and outputting a message indicating low tire pressure of one of the wheels in response to the difference exceeding the difference threshold.

[0079] In one aspect of the invention, the method includes: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle steering angle being within a steering angle range.

[0080] In one aspect of the invention, the method includes: determining the difference between the wheel rotation speeds in response to the speed exceeding the vehicle speed threshold and the vehicle's tire pressure monitoring system being inactive.

[0081] In one aspect of the invention, the vehicle includes a corresponding tire pressure monitoring system for each wheel; the method further includes: in response to the speed exceeding the vehicle speed threshold and at least one of the tire pressure monitoring systems being inactive, determining the difference between the wheel rotational speeds.

[0082] In one aspect of the invention, the method includes: determining the difference between the wheel rotational speeds in response to the speed exceeding the vehicle speed threshold for at least a certain time threshold.

[0083] In one aspect of the invention, the method includes: determining the difference between the wheel rotational speeds in response to the speed exceeding the vehicle speed threshold and the current operating mode of the vehicle being a first operating mode.

[0084] In one aspect of the invention, the difference is between the fastest wheel speed and the slowest wheel speed.

Claims

1. A method comprising: In response to the vehicle speed exceeding a vehicle speed threshold, the difference between the wheel rotation speeds of different wheels of the vehicle is determined; and In response to the difference exceeding a difference threshold, a message indicating low tire pressure in one of the wheels is output.

2. The method according to claim 1, further comprising: In response to the speed exceeding the vehicle speed threshold and the vehicle's steering angle being within the steering angle range, the difference between the wheel speeds is determined.

3. The method according to claim 2, wherein the steering angle range includes the straight-line forward steering angle.

4. The method according to claim 1, further comprising: In response to the speed exceeding the vehicle speed threshold and the vehicle's tire pressure monitoring system being inactive, the difference between the wheel speeds is determined.

5. The method of claim 1, wherein the vehicle includes a corresponding tire pressure monitoring system for each tire; The method further includes: In response to the speed exceeding the vehicle speed threshold and at least one of the tire pressure monitoring systems being inactive, the difference between the wheel speeds is determined.

6. The method according to claim 1, further comprising: In response to the speed exceeding the vehicle speed threshold for at least a certain period of time, the difference between the wheel rotation speeds is determined.

7. The method according to claim 1, further comprising: In response to the speed exceeding the vehicle speed threshold and the vehicle's current operating mode being a first operating mode, the difference between the wheel rotation speeds is determined.

8. The method of claim 1, wherein the difference is between the fastest wheel speed and the slowest wheel speed.

9. The method according to claim 8, wherein the fastest wheel speed and the slowest wheel speed occur simultaneously.

10. The method of claim 8, wherein the difference is represented as a proportion of the slowest wheel speed.

11. The method according to claim 1, further comprising: In response to the difference exceeding the difference threshold, a flag is set in the memory.

12. The method of claim 11, further comprising: In response to the vehicle starting with the flag set, the message indicating low tire pressure is output.

13. The method of claim 11, further comprising: In response to the fact that the difference is less than the difference threshold for at least a certain period of time after the flag is set, the flag is removed.

14. A computer comprising a processor and a memory storing instructions executable by the processor to perform the method according to any one of claims 1 to 13.

15. A vehicle comprising the computer according to claim 14.

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