METHOD FOR DETECTING DAMAGE TO A VEHICLE TIRE

Description

[0001] The invention relates to a method and a device for detecting damage to a vehicle tire. Damage to a vehicle tire can lead to a relatively slow loss of air from the vehicle tire and thus to a slow pressure drop.

[0002] Methods for detecting gradual pressure loss in vehicle tires are known. In such methods, a curve gradient is determined from stored tire pressure values ​​of a tire pressure sensor, which represents the pressure loss per unit of time. If the determined curve gradient deviates sufficiently from a specified curve gradient, a warning message is issued.

[0003] EP 1 813 447 A2 discloses a system for monitoring tire pressure, comprising a tire pressure sensor, a transmitter, and a receiver. A tire pressure signal can be processed in a computer unit and a warning signal can be output. The warning signal is output when damage is detected, even if the pressure loss is not progressing, since the damage does not lead to further pressure loss due to the action of a repair fluid.

[0004] EP 2 818 338 A1 discloses a system for detecting a tire burst comprising a tire pressure sensor and a tire pressure monitor which, when a tire bursts, indicates the bursting of the tire by means of a binary display device and prevents a display of a tire with low pressure.

[0005] EP 1 889 736 A1 discloses a tire monitoring system comprising a tire monitoring unit and a central control unit. The central control unit sends voice commands and brake deceleration commands to a voice command unit and a brake deceleration mechanism depending on the signals from the tire monitoring unit.

[0006] Against this background, the invention is based on the object of improving a method and a device for detecting damage to a vehicle tire so that damage to a vehicle tire is detected at an early stage.

[0007] This object is achieved by a method according to the features of patent claim 1 and a device according to the independent claim. The subclaims relate to particularly useful developments of the invention.

[0008] According to the invention, a method for detecting damage to a vehicle tire is provided, comprising the following steps: a) Recording individual tire pressure values ​​of the vehicle tire with a tire pressure sensor, b) Comparing the tire pressure value with a lower threshold, c) Initiating a warning message if one of the tire pressure values ​​falls below a lower threshold, The time of initiation of the warning message or the exceeding of an upper threshold is stored as a first time in a data memory. Subsequently, a second time is recorded due to one of the tire pressure values ​​of the vehicle tire falling below a lower threshold. The second time is compared with the first time, and a damage report is initiated if a comparison of the first time with the second time results in a time difference smaller than a predetermined minimum time difference.

[0009] Initiating a warning message is not the same as repeatedly issuing or displaying the same warning message due to a tire pressure value consistently below a threshold. Initiating a warning message is only executed if the tire pressure value is previously above the lower threshold and subsequently below the lower threshold.

[0010] In an advantageous embodiment, no damage report is issued if the tire pressure value has not exceeded the upper threshold after the first time, with the upper threshold preferably being at least 0.5 bar higher than the lower threshold. If the first time corresponds to the time at which the upper threshold is exceeded, a damage report is always issued if the time difference until the tire pressure falls below the lower threshold is less than the predetermined minimum time difference.

[0011] If the first time corresponds to the time when the tire pressure falls below the lower threshold, no damage report is issued if the tire pressure has not exceeded the upper threshold in the meantime. This prevents the issue of a damage report by alternating the tire pressure value around the lower threshold.

[0012] A further advantageous development detects a vehicle tire temperature and performs temperature compensation of the tire pressure values. This prevents fluctuations in the tire pressure values ​​due to temperature fluctuations. Alternating the tire pressure value around the lower threshold is avoided, and a second threshold for determining tire damage can be eliminated. Any undershoot of the lower threshold results in the output of a warning or damage message.

[0013] In a further advantageous embodiment, the first time point and preferably also other determined data are stored in a data storage device located on a vehicle, preferably in the vehicle tire. This eliminates the need to transmit the first time point to a data storage device external to the vehicle. Preferably, the transmission from a device located in the tire to the vehicle can also be eliminated, thus saving the energy required for transmission.

[0014] In a further advantageous embodiment, the first time point, and preferably also other determined data, are stored on a central data storage device outside the vehicle. Storing data on a central data storage device makes it possible to implement the unit located in the tire without a data storage device, making it particularly small, lightweight, and inexpensive to manufacture. Furthermore, centralized data evaluation can be performed in a simple manner, enabling a damage report to be issued, for example, to a fleet operator.

[0015] A further preferred embodiment provides for the comparison of the first time with the second time and / or alternatively the initiation of the damage notification on the vehicle, preferably on a tire pressure monitoring system located in the vehicle tire. This eliminates the need for data transmission to a central data storage device. Preferably, data transmission from the vehicle tire to the vehicle can also be minimized, since data only needs to be transmitted when a warning or damage notification is issued.

[0016] In a further advantageous embodiment, the comparison of the first time with the second time and the initiation of the damage report takes place on a central computer. The units located in the tire and in the vehicle can be particularly small, lightweight, and inexpensive to manufacture.

[0017] A further preferred embodiment provides that the first time and the second time, and / or alternatively, the warning messages and damage messages are output wirelessly from the tire pressure sensor, preferably via radio transmission, more preferably via Bluetooth, to a control unit of the vehicle. Wireless transmission is particularly easy to implement for rotating components such as vehicle tires. Transmission via radio or Bluetooth enables particularly cost-effective and reliable transmission.

[0018] A further preferred embodiment provides that the first time and the second time, and / or alternatively, the warning messages and damage messages from the tire pressure sensor are transmitted wirelessly, preferably via a mobile network, to a central computer outside the vehicle. This eliminates the need to install a control unit on the vehicle, making this embodiment smaller, lighter, and less expensive to manufacture.

[0019] InIn a further advantageous development, the predetermined minimum time difference is one month, preferably two weeks, more preferably one week, and more preferably three days. The greater the predetermined minimum time difference, the slower the pressure losses are detected as tire damage. However, a large predetermined minimum time difference increases the frequency of false or unnecessary damage reports. The pressure loss rates vary depending on the vehicle tire and its use. Thus, larger predetermined minimum time differences are advantageous for some vehicle tires and uses, while smaller predetermined minimum time differences are advantageous for others. It is therefore further advantageous if the predetermined minimum time difference is adapted to the vehicle tire and its use. This can preferably be done by a learning algorithm that determines a predetermined minimum time difference based on previous pressure losses.

[0020] A further preferred embodiment provides that a damage report is initiated if the time difference occurs multiple times, wherein the time span between the time differences is less than three months, preferably less than two months, more preferably less than one month, and more preferably less than two weeks. This avoids the likelihood of unnecessary damage reports, while even minor damages continue to be detected with a high degree of certainty.

[0021] A one-time increase in pressure loss rate, which may be caused, for example, by intensive use, will not be issued as a damage alert, as the predetermined minimum time difference can be selected to be small. However, if a minor damage repeatedly leads to an increased pressure loss rate, this results in a more frequent warning alert, so that a damage alert is issued without the pressure loss being so great that it results in a time difference that is smaller than the predetermined minimum time difference. Depending on the vehicle tire and its use, a longer or shorter time period is advantageous, as already explained for the predetermined minimum time difference.

[0022] In another advantageous development, the damage report is automatically sent to a fleet operator and / or alternatively to a vehicle owner. This automated notification ensures that the fleet operator or vehicle owner is immediately informed of the damage and can schedule service and issue appropriate instructions to the driver. The notification can be sent via email, for example.

[0023] A further preferred embodiment provides that the frequency of the warning messages of the vehicle tire is compared with the frequency of the warning messages of other vehicle tires of the same vehicle, wherein if the frequencies deviate by more than a factor of 5, preferably by more than a factor of 3, more preferably by more than a factor of 2 and more preferably by more than a factor of 1.5, a damage message is initiated.

[0024] This enables the detection of damage that only results in a small pressure loss rate, while minimizing the likelihood of unnecessary damage reports. The predetermined minimum time difference can be selected to be small, resulting in fewer unnecessary damage reports. Small increases in the pressure loss rate are still detected if the pressure loss rate is higher by a factor of the same as other tires on the vehicle. An increased pressure loss rate due to intensive use does not result in unnecessary damage reports.

[0025] According to the invention, a device for carrying out the method according to the invention is provided. The device comprises a tire pressure monitoring system for determining tire pressure values, a memory unit for storing times, a transmitter unit, and a computing unit for detecting damage to a vehicle tire. The tire pressure monitoring system for determining tire pressure values, as well as a transmitter unit, are arranged in the vehicle tire. The memory unit and the computing unit can be arranged in the vehicle, for example, in the vehicle tire, or outside the vehicle, for example, centrally for a plurality of vehicles.

[0026] The invention permits numerous embodiments. To clarify its basic principle, two of them are shown in the drawings and are described below. These show in Fig. 1a schematic method for detecting damage to a vehicle tire, Fig. 2 a course of a tire pressure value over time.

[0027] Figure 1 schematically shows a method for detecting damage to a vehicle tire, wherein a tire pressure value 1 of the vehicle tire is repeatedly recorded with a tire pressure sensor and compared with a lower threshold value 2. If a tire pressure value 1 is recorded that is below the lower threshold value 2, a warning message is issued to a vehicle driver.

[0028] The time at which the warning message is initiated is stored as a first time 3 in a vehicle's data storage device. Temperature compensation of the tire pressure value 1 is performed so that temperature fluctuations of the tire do not lead to a change in the tire pressure value 1. The tire pressure value 1 is thus not subject to any relevant fluctuations and remains below the lower threshold value 2 until the vehicle tire is filled.

[0029] A renewed undershoot of the tire pressure value 1 below the lower threshold 2, i.e. a tire pressure value 1 below the lower threshold 2, where the previous tire pressure value 1 was above the lower threshold 2, therefore only occurs after the vehicle tire has been inflated in the meantime. The time at which the lower threshold 2 is again undershot is stored as a second time 4 in a vehicle data memory. A comparison is made between the first time 3 and the second time 4, with a damage report being issued if the time difference between the first time 3 and the second time 4 is less than a predetermined minimum time difference 5. The damage report is issued to the vehicle driver and by email to a central processing unit.

[0030] In Figure 2A curve of the tire pressure value 1 over time is shown. Time is plotted on the x-axis 6, and the tire pressure on the y-axis 7. This embodiment does not feature temperature compensation for the tire pressure, so the temperature-related fluctuations in the tire pressure value 1 are superimposed on the curve of the tire pressure value 1 as small and short fluctuations.

[0031] In a first sub-area 8, the vehicle tire is undamaged and thus has a nearly constant tire pressure value 1. At the time of damage 9, the vehicle tire is damaged, so that, over a period of several days, the tire pressure value 1 falls below the lower threshold value 2. This is determined by recording the tire pressure value 1 and comparing the tire pressure value 1 with the lower threshold value 2. A warning message is issued.

[0032] An inflation 10 of the vehicle tire is performed so that the tire pressure value 1 exceeds an upper threshold value 11. This is determined by comparing the upper threshold value 11 with the recorded tire pressure value 1. The time at which the upper threshold value 11 is exceeded is stored as the first time 3.

[0033] The tire pressure value 1 then drops again and falls below the lower threshold value 2 at time 12. This is determined by comparing the lower threshold value 2 with the detected tire pressure value 1. The time 12 is stored as the second time 4 and compared with the first time 3. The difference between the second time 4 and the first time 3 is compared with the predetermined minimum time difference 5. The comparison shows that the predetermined minimum time difference 5 is greater than the difference between the second time 4 and the first time 3, so that a damage report is issued. List of reference symbols

[0034] 1Tire pressure value 2Lower threshold 3First time point 4Second time point 5Predetermined minimum time difference 6X-axis 7Y-axis 8First sub-range 9Damage time point 10Filling 11Upper threshold 12Time point

Claims

1. Method for detecting damage to a vehicle tyre, having at least the following steps: a) recording individual tyre pressure values (1) of the vehicle tyre using a tyre pressure sensor, b) comparing the tyre pressure value (1) with a lower threshold value (2), c) initiating a warning notification if one of the tyre pressure values (1) falls below the lower threshold value (2), characterized in that the time at which the warning notification is initiated or an upper threshold value (11) is exceeded is stored as a first time (3) in a data memory, wherein a second time (4) is subsequently recorded due to one of the tyre pressure values (1) of the vehicle tyre falling below a lower threshold value (2), and is compared with the first time (3), wherein a damage notification is initiated if a comparison of the first time (3) with the second time (4) results in a time difference that is less than a predetermined minimum time difference (5).

2. Method according to Claim 1, characterized in that a damage notification is not output as long as the tyre pressure value (1) has not exceeded the upper threshold value (11) after the first time (3).

3. Method according to Claim 1 or 2, characterized in that a vehicle tyre temperature is recorded and temperature compensation of the tyre pressure value (1) is carried out.

4. Method according to one of the preceding claims, characterized in that the first time (3) is stored in a data memory located on a vehicle, preferably in the vehicle tyre.

5. Method according to one of the preceding claims, characterized in that the first time (3) is stored in a central data memory outside of the vehicle.

6. Method according to one of the preceding claims, characterized in that the first time (3) is compared with the second time (4) and / or the damage notification is initiated at the vehicle, preferably on a tyre pressure monitoring system located in the vehicle tyre.

7. Method according to one of Claims 1 to 5, characterized in that the first time (3) is compared with the second time (4) and the damage notification is initiated on a central computer.

8. Method according to one of the preceding claims, characterized in that the first time (3) and the second time (4) and / or the warning notifications and damage notifications are output from the tyre pressure sensor to a control device of the vehicle in a wireless manner, preferably by means of radio transmission, more preferably by means of Bluetooth.

9. Method according to one of Claims 1 to 7, characterized in that the first time (3) and the second time (4) and / or the warning notifications and damage notifications are output from the tyre pressure sensor to a central computer in a wireless manner, preferably via a mobile radio network.

10. Method according to one of the preceding claims, characterized in that the predetermined minimum time difference (5) is one month, preferably two weeks, more preferably one week, and more preferably three days.

11. Method according to one of the preceding claims, characterized in that a damage notification is initiated if the time difference occurs multiple times, wherein the time period between the time differences is less than three months, preferably less than two months, more preferably less than one month and more preferably less than two weeks.

12. Method according to one of the preceding claims, characterized in that the damage notification is automatically output to a fleet operator and / or a vehicle owner.

13. Method according to one of the preceding claims, characterized in that the frequency of the warning notifications of the vehicle tyre is compared with the frequency of the warning notifications of other vehicle tyres of the same vehicle, wherein a damage notification is initiated if the frequencies differ by more than a factor of 5, preferably by more than a factor of 3, more preferably by more than a factor of 2, and more preferably by more than a factor of 1.5.

14. Apparatus for carrying out the method according to Claim 1, having: - a tyre pressure monitoring system for ascertaining tyre pressure values, - a memory unit for storing times, - a transmitting unit, - a computing unit for ascertaining damage to a vehicle tyre.