METHOD FOR MONITORING TIRE STATES AND/OR SENSOR STATES AND A MONITORING SYSTEM THEREFOR

Abstract

A method is for monitoring tire states and/or sensor states. The method includes the steps: a) capturing whether at least one tire sensor module for measuring tire states and/or sensor states is present in a monitoring region; b) determining whether the captured tire sensor module is unknown; c) evaluating data messages from the at least one captured and unknown tire sensor module, the evaluation including at least comparing at least one tire state transmitted via the data message with a limit value therefor and/or monitoring a sensor state of the tire sensor module transmitted via the data message; and, d) outputting a warning signal if a tire state exceeds or undershoots the respective limit value in order to indicate that a tire state of a tire assigned to the at least one unknown tire sensor module is critical and/or if a critical sensor state is detected.

Claims

1. A method for monitoring at least one of tire states and sensor states, the method comprising the steps of: a) capturing whether at least one tire sensor module for measuring at least one of the tire states and sensor states is present in a monitoring region; b) determining whether the at least one captured tire sensor module is unknown; c) evaluating data messages (S1) from the at least one captured and unknown tire sensor module, the evaluation comprising at least one of comparing at least one tire state transmitted via a data message (S1) with a limit value (GW) therefor and monitoring a sensor state of the tire sensor module transmitted via the data message (S1); and, d) outputting a warning signal (S2) if at least one of: one of said tire states exceeds or undershoots the respective limit value (GW) in order to indicate that a tire state of a tire assigned to the at least one unknown tire sensor module is critical; and, a critical sensor state is detected.

2. The method of claim 1, wherein at least one of a tire temperature (T), a tire pressure (p), a mechanical stress state (), a tread depth, and a wheel load is measured or determined as the tire state by the tire sensor module and is outputted via the data message (S1).

3. The method of claim 2, wherein the limit value (GW) for the tire pressure (p) is less than or equal to 80% of a desired pressure (pSoll) for outputting the warning signal (S2) if the tire pressure (p) of the corresponding tire undershoots the desired pressure value (pSoll) by more than 20%.

4. The method of claim 2, wherein the limit value (GW) for the tire temperature (T) is less than or equal to 120% of a desired temperature (TSoll) for outputting the warning signal (S2) if the temperature of the corresponding tire exceeds the limit value by more than 20%.

5. The method of claim 1, wherein at least one of a sensor defect and a loose sensor is detected as a critical sensor state by the tire sensor module and is output via the data message (S1).

6. The method of claim 1, wherein a sensor identification or sensor identifier is output by the tire sensor module via the data message (S1) in order to determine whether the tire sensor module is unknown.

7. The method of claim 1, wherein the tire sensor module captures whether the tire sensor module is moving and the movement state is outputted via the data message (S1).

8. The method of claim 7, wherein a tire state output via the data message (S1) is compared with the limit value (GW) or the sensor state is monitored only when the movement state of a driver's own commercial vehicle corresponds to the movement state of the captured and unknown tire sensor module.

9. The method of claim 8, wherein a tire state output via the data message (S1) is compared with the limit value (GW) or the sensor state is monitored only when both the driver's own commercial vehicle and the captured and unknown tire sensor modules are moving.

10. The method of claim 1 further comprising the steps of: determining whether the at least one captured and unknown tire sensor module belongs to a trailer vehicle of a driver's own commercial vehicle; monitoring a number of output data messages (S1) from the at least one captured and unknown tire sensor module in a period (dT) for the purpose of said determining whether at least one captured and unknown tire sensor module belongs to a trailer vehicle of a driver's own commercial vehicle; and, wherein the data messages (S1) are already evaluated in step c) before it has been determined whether the at least one captured tire sensor module belongs to the driver's own trailer vehicle.

11. A monitoring system for monitoring at least one of tire states and sensor states, the monitoring system comprising: a control unit; a receiving module; said control unit being configured to capture, via said receiving module, whether at least one tire sensor module for measuring tire states is present in a monitoring region of said receiving module; said control unit being further configured to determine whether the at least one captured tire sensor module is unknown to the control unit; said control unit being further configured to evaluate a data message (S1) from the captured and unknown tire sensor module, said evaluation comprising at least comparing at least one tire state transmitted via the data message (S1) with a limit value (GW) therefor and/or monitoring a sensor state of the tire sensor module; and, said control unit being further configured to output a warning signal (S2) if at least one of: a tire state exceeds or undershoots said limit value (GW) in order to indicate that a tire state of a tire assigned to the tire sensor module is critical, and, there is a critical sensor state.

12. The monitoring system of claim 11, wherein: said control unit is also configured to determine whether a captured and unknown tire sensor module belongs to a trailer vehicle of a driver's own commercial vehicle; said control unit is configured to monitor a number of data messages (S1) output by the captured and unknown tire sensor module in a period (dT) for the purpose of determining whether a captured and unknown tire sensor module belongs to the trailer vehicle of the driver's own commercial vehicle; and, said control unit being further configured to carry out the evaluation before it has been determined whether the captured tire sensor module belongs to the trailer vehicle of the driver's own commercial vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will now be described with reference to the drawings wherein:

[0027] FIG. 1 shows a commercial vehicle having a towing vehicle and a trailer vehicle and an adjacent commercial vehicle; and,

[0028] FIG. 2 shows a flowchart for monitoring a tire state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0029] FIG. 1 shows a commercial vehicle 1 having a towing vehicle 2 and a trailer vehicle 3. A control unit 4 (ECU) which is connected to a receiving module 5 is provided on the towing vehicle 2. A receiving module (not illustrated) may likewise be included in the control unit 4. In this case, the receiving module 5 is preferably arranged at a rear end of the towing vehicle 2. The receiving module 5 is configured to receive a data message S1 from tire sensor modules 6.i, with i=1 to 4. According to FIG. 1, the tire sensor modules 6.i are arranged, by way of example, only on the tires 7, 8, 9, 10 of the trailer vehicle 3 and each wirelessly output a data message S1, for example via a radio-frequency radio signal. Further tire sensor modules (not illustrated) are arranged on the tires of the towing vehicle 2, the radio signals from which can be received, in particular, by the receiving module 5 and possibly by the further receiving module in the control unit 4. The control unit 4 further processes the signals received by the receiving module 5. In this case, the control unit 4 and the receiving module 5 and possibly the further receiving module in the control unit 4 form a monitoring system 100 for monitoring tire states p, T, and critical sensor states using the tire sensor modules 6.i and possibly further tire sensor modules 106.i, 107.i.

[0030] In this case, the tire sensor modules 6.i are each arranged on the tire 7, 8, 9, 10 and can capture tire states, for example a tire pressure p, a tire temperature T and mechanical stresses G, can process the captured tire states p, T, and can wirelessly output them via the data message S1. Furthermore, a sensor identification or a sensor identifier, a critical sensor state, for example a sensor defect or a loose tire sensor module 6.i, and a movement state of the respective tire 7, 8, 9, 10 can be output via the data message S1.

[0031] If such a tire sensor module 6.i is in a monitoring region 11 of the receiving module 5 or of the control unit 4, the tire sensor module 6.i can be initially captured by the control unit 4 and a check can then be carried out in order to determine whether this tire sensor module 6.i is arranged on one of the tires of the driver's own towing vehicle 2, that is, is already known. This can be carried out on the basis of the sensor identification, for example.

[0032] If the captured tire sensor module 6.i is unknown, the data message S1 is evaluated by comparing the tire states p, T, transmitted via the data message S1 with limit values GW, the limit values GW specifying percentage deviations from a desired value, for example a desired temperature TSoll or a desired pressure pSoll or a desired stress Soll. If the limit values GW are undershot or exceeded, that is, there is an excessively low tire pressure p or an excessively high tire temperature T for example, the control unit 4 outputs a warning signal S2 to the driver. If a plurality of unknown tire sensor modules 6.i are captured, the data messages S1 from all tire sensor modules 6.i are evaluated in a parallel manner.

[0033] Furthermore, the control device 4 monitors the sensor states transmitted via the data message S1 and outputs a warning signal S2 to the driver if a critical sensor state is detected.

[0034] The monitoring region 11 may be 20 to 25 m, for example. This also makes it possible to capture unknown tire sensor modules 106.i, 107.i on tires 108.i and 109.i of an adjacent commercial vehicle 101 which has a towing vehicle 102 and a trailer vehicle 103 and is at least partially in the monitoring region 11 according to FIG. 1. So that an excessively large number of warning signals S2 are not output to the driver when evaluating the data messages S1 from all captured and unknown tire sensor modules 6.i, 106.i, 107.i, the limit values GW are stipulated in such a manner that the driver receives a notification only in the case of tire states which are critical to driving. For example, the limit value GW for the tire pressure p can be limited to a value of less than or equal to 80% of the desired pressure pSoll, for example to 20% reduced pressure, that is, 80% of the desired pressure pSoll or GW=0.8pSoll, as a result of which only slight fluctuations in the tire pressure p which do not result in a critical driving situation do not trigger a warning signal S2. Furthermore, the sensor states in which a warning signal S2 is triggered can also be restricted.

[0035] Since it is initially unclear during evaluation immediately after capture whether the unknown tire sensor module 6.i, 106.i, 107.i is arranged on a tire 7, 8, 9, 10 of the driver's own trailer vehicle 3, the driver must himself check, in the event of a warning signal S2, whether this signal comes from a tire sensor module 6.i of his own trailer vehicle 3 or of the adjacent commercial vehicle 101 by checking the tires 7, 8, 9, 10 and 108.i and 109.i.

[0036] Automatic trailer detection is additionally carried out in the control unit 4, which detection determines or checks over a period dT whether the received data messages S1 are output by the tire sensor modules 6.i of the driver's own trailer vehicle 3. If a corresponding number of tire sensor modules 6.i have been detected for the driver's own trailer vehicle 3, the trailer detection can be switched off in order to avoid unnecessary warning signals S2.

[0037] One embodiment of the method provides for the movement state output by the tire sensor modules 6.i, 106.i, 107.i to be taken into account in the evaluation. In this case, the tire sensor modules 6.i, 106.i, 107.i determine, for example from a prevailing radial acceleration, whether the corresponding tire is moving or is stationary, that is, whether the vehicle with this tire is in a driving state or at a standstill or is moving slowly.

[0038] In order to avoid generating unnecessary warning signals S2, it is therefore possible to take into account whether the data messages S1 or the tire states p, T, or sensor states are output by tire sensor modules 6.i, 106.i, 107.i which have the same movement state as the driver's own towing vehicle 2. Therefore, in the case of a towing vehicle 2 which is parked, is at a standstill or is moving slowly, all tire sensor modules 6.i, 106.i, 107.i which are moving at a speed corresponding to a vehicle speed of 20 km/h or more, for example, can be excluded from the evaluation. Additionally or alternatively, in the case of a towing vehicle 2 moving at more than 20 km/h, all tire sensor modules 6.i, 106.i, 107.i which are not moving or are moving only slowly can be excluded in the evaluation.

[0039] A method according to the invention can, for example, be carried out as follows according to FIG. 2:

[0040] In a step St0, the method begins, for example, with the starting of the commercial vehicle 1 or after the commercial vehicle 1 has not been driven for a particular time of 15 minutes, for example. After step t0, the method branches, the automatic trailer detection, that is, the determination of whether or not an unknown tire sensor module 6.i, 106.i, 107.i is assigned to the driver's own trailer vehicle 3, being carried out in a first branch, and the tire states p, T, or sensor states being monitored according to the invention in a second branch running parallel thereto.

[0041] In the first branch, a first step St1.1 captures whether the driver's own commercial vehicle 1 is moving. If this is not the case, the data messages S1 received from the at least one unknown tire sensor module 6.i, 106.i, 107.i in the monitoring region 11 are discarded since the automatic trailer detection is carried out only in the case of a moving commercial vehicle 1. No warning signals S2 are accordingly output either.

[0042] If a movement of the driver's own commercial vehicle 1 is captured, the sensor identification(s) of the unknown tire sensor module or of all unknown tire sensor modules 6.i, 106.i, 107.i transmitted via the data message S1 is/are collected and counted over a period dT in a second step St1.2 of this branch, only moving tire sensor modules 6.i, 106.i, 107.i being taken into account for this purpose. No warning signals S2 are output in the meantime.

[0043] In the second branch, the data messages S1 from the unknown tire sensor modules 6.i, 106.i, 107.i are already evaluated in a parallel manner when the commercial vehicle 1 is stationary in a first step St2.1. For this purpose, the tire states p, T, transmitted via the data message S1 are each compared with a limit value GW and the sensor states are monitored for critical sensor states. If the limit value GW is accordingly exceeded or undershot or if there is a critical sensor state, warning signals S2 are output. According to this embodiment, only tire sensor modules 6.i, 106.i, 107.i which are likewise not moving are evaluated in this case.

[0044] In addition, in a step St2.2, the data messages S1 from the unknown tire sensor modules 6.i, 106.i, 107.i are also evaluated when the commercial vehicle 1 is moving by comparing each of the transmitted tire states p, T, with a limit value GW or by monitoring the sensor state. If the limit value GW is accordingly exceeded or undershot, warning signals S2 are output. Warning signals S2 are likewise output if the sensor state indicates a defect, for example. According to this embodiment, only tire sensor modules 6.i, 106.i, 107.i which are likewise moving are evaluated in this case.

[0045] After steps St1.2 and St2.2, the branches converge again. After these steps, the automatic trailer detection has been concluded. Accordingly, after the tire sensor modules 6.i have been assigned to the driver's own trailer vehicle 3, the automatic trailer detection is concluded in step St3 and the tire sensor modules 6.i which are now known are permanently monitored, for example, until the automatic trailer detection is restarted.

[0046] Alternatively, provision may be made for the data messages S1 to not yet be used in step St2.1. That is, in a method according to the invention for monitoring tire states and sensor states, warning signals S2 are output only in the driving state if the limit value is exceeded or undershot and/or a critical sensor state has been determined, only tire sensor modules 6.i, 106.i, 107.i which are likewise moving being taken into account according to this embodiment.

[0047] It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

LIST OF REFERENCE SIGNS

[0048] 1 Driver's own commercial vehicle [0049] 2 Towing vehicle [0050] 3 Trainer vehicle [0051] 4 Control unit [0052] 5 Receiving module [0053] 6.i Tire sensor modules [0054] 7, 8, 9, 10 Tires of the trailer vehicle 3 [0055] 11 Monitoring region [0056] 100 Monitoring system [0057] 101 Adjacent commercial vehicle [0058] 102 Towing vehicle of 101 [0059] 103 Trailer vehicle of 101 [0060] 106.i Tire sensor modules on 103 [0061] 107.i Tire sensor modules on 102 [0062] 108.i Tires of the adjacent trailer vehicle 103 [0063] 109.i Tires of the adjacent towing vehicle 102 [0064] dT Period [0065] GW Limit values [0066] p Tire pressure [0067] pSoll Desired pressure [0068] T Tire temperature [0069] TSoll Desired temperature [0070] Mechanical stress state [0071] Soll Desired stress [0072] S1 Data message [0073] S2 Warning signals [0074] St0, St1.1, St1.2, St2.1, St2.2, St3 Method steps