DEVICE FOR MONITORING TIRE PRESSURE

Description

[0001] The present invention relates to a device and a method for monitoring tire pressure, and in particular to tire pressure monitoring in commercial vehicles.

[0002] Two common approaches to tire pressure monitoring are currently available. Direct-sensing tire pressure monitoring systems use pressure and temperature sensors on each individual wheel. These are typically mounted on the rim side or on the inside of the tire and are in direct contact with the air within the tire. Pressure and temperature are measured in real time and transmitted telemetrically to a control unit in the commercial vehicle. The driver is often shown a tire pressure reading for each individual tire.

[0003] In contrast, indirectly detecting or measuring tire pressure monitoring systems are based on changes in the wheels or their behavior. They determine tire pressure only indirectly. A change in tire pressure, in particular, changes the tire's rolling behavior; in particular, the speed can increase if the tire's radius decreases with decreasing internal pressure. Indirectly measuring tire pressure monitoring systems therefore use speed sensors to detect such changes and use them to determine the tire pressure.

[0004] Document EP 1 236 588 A2 discloses a tire pressure monitoring system for a vehicle with rotational speed sensors and a tire pressure measuring system for an absolute tire inflation pressure, which may in particular have rotational speed sensors on a single-tire first axle and a twin-tire second axle, and tire pressure measuring devices on the twin-tire second axle and a twin-tire third axle.

[0005] Document DE 10 2019 211 839 A1 discloses a tire pressure measuring system for twin-tyred axles that determines a combination of the pressures in the twin tires.

[0006] The disadvantages of direct-measuring tire pressure monitoring systems are their cost, as at least one sensor is required for each tire. Furthermore, the sensors are typically powered by their own batteries, which in many cases means they need to be replaced after approximately five to eight years.

[0007] Indirectly measuring tire pressure monitoring systems are generally significantly more cost-effective than directly measuring tire pressure monitoring systems because they utilize components already present in the vehicle for other purposes (such as the speed sensors) and simplify maintenance, particularly of the tires. However, the disadvantages of indirectly measuring tire pressure monitoring systems include, in particular, the reduced accuracy of pressure determination. Commercial vehicles also often have double or twin-tired axles, where indirectly measuring tire pressure monitoring systems often cannot distinguish between the two (or more) tires.

[0008] There is therefore a need for improved, particularly more cost-effective and efficient tire pressure monitoring devices.

[0009] According to the invention, some of the problems mentioned are solved by a device according to claim 1, a commercial vehicle according to claim 5 and a method according to claim 8. The dependent claims define further advantageous embodiments of the subject matter of the independent claims.

[0010] The present invention relates to a device for monitoring tire pressure for a commercial vehicle having both an axle with at least twin tires, comprising a first tire and a second tire, and an axle with a single tire, comprising a third tire. A twin-tired or double-tired axle is understood to mean an axle in which two tires are mounted on two separate or a common rim on a wheel hub or other axle mount. The first and second tires can thus be mounted directly next to one another. The axle with a single tire, referred to in an analogous manner, can also have a single tire with an extra width (so-called super-single tire).

[0011] The device comprises a first pressure sensor configured to measure a first pressure in the first tire and a second pressure sensor configured to measure a second pressure in the second tire. The first and second pressure sensors can be attached to a rim side or to an inner side of the first and second tires, respectively; they are advantageously in direct contact with the air in the respective tire.

[0012] The device further comprises a rotational speed sensor configured to measure a rotational speed of the third tire or a corresponding wheel. Furthermore, the device comprises a first control module configured to receive and monitor the first pressure and the second pressure, and a second control module configured to receive the rotational speed, determine a third pressure in the third tire based on the rotational speed, and monitor the third pressure.

[0013] Monitoring may include repeatedly measuring the respective pressure and / or comparing data obtained by measuring at different times or with values from a table or other profile or pattern. The table, profile, or pattern may be stored in the respective control module. Furthermore, monitoring may include issuing a warning signal to a driver or to another component of the commercial vehicle. A warning may be issued, for example, if one of the pressures or a rate of change of one of the pressures exceeds and / or falls below a threshold.

[0014] The two control modules can be housed in different electronic control units, which can also belong to different subsystems (e.g. braking system, steering system, etc.). Other devices of the commercial vehicle include: For example, the first control module and / or the first and second pressure sensors can thus be provided exclusively for monitoring the tire pressure, while the second control module and / or the speed sensor can be part of a driving stability system, for example, wherein the driving stability system is designed to also use the speed for other purposes. In particular, the driving stability system can be, for example, an anti-lock braking system, a traction control system, or an electronic stability program, the function of which in each case requires or provides for the measurement of the speed by the speed sensor.A data connection can be established between the control modules, particularly when implemented in different control units, via which data for monitoring the respective pressures can be exchanged and / or warnings can be coordinated.

[0015] The commercial vehicle may, of course, have additional tires and also additional axles, and the device may comprise corresponding additional pressure sensors and additional speed sensors.

[0016] In particular, the dual-tire axle can carry a further first tire and a further second tire, which also each have a corresponding further pressure sensor for measuring a further first pressure and a further second pressure. The first control module can be configured to receive and monitor the further first and the further second pressure. Furthermore, the single-tire axle can also carry a further third tire, and the device can comprise a further pressure sensor for measuring a corresponding further rotational speed of the further third tire. The second control module can also be configured to receive the further rotational speed, to determine a further third pressure in the further third tire from the further rotational speed, and to monitor the further third pressure.

[0017] Accordingly, the commercial vehicle may also have one or more additional twin-tyre axles and / or additional single-tyre axles, the wheels or tires of which are connected in a corresponding manner to the first and second control modules, so that the device can also monitor pressures in the tires on these additional axles.

[0018] The different tires can also be mounted on different sides of the commercial vehicle.

[0019] The possibility of expanding the device described above naturally also applies to all aspects and optional designs of the device and corresponding methods described below.

[0020] Optionally, the device comprises at least one further rotational speed sensor designed to measure a further rotational speed of a tire or wheel of the commercial vehicle, wherein the second control module is designed to receive the further rotational speed and to determine the third pressure in the third tire based on the further rotational speed. The further rotational speed can be a rotational speed of the first and / or the second tire or wheel, but also a rotational speed of another tire or wheel of the commercial vehicle. In particular, the second control unit can be designed to determine the third pressure by comparing the rotational speed of the third wheel with the further rotational speed.

[0021] Optionally, the first control module and the second control module are combined in a single control unit or housed separately in different control units. In particular, the control unit can be configured to receive the first and / or second pressure telemetrically. The control unit can be further configured to query the rotational speed, for example, via a CAN bus of the commercial vehicle; the rotational speed sensor can also be part of another component (in particular, a driving stability system) of the commercial vehicle.

[0022] Optionally, the first control module is configured to combine the first pressure and the second pressure into a combined pressure and to monitor the combined pressure. The combining may, for example, involve calculating an arithmetic mean of the first pressure and the second pressure. However, the combining may also be based on another function that assigns an output value for the combined pressure to an input value for the first pressure and an input value for the second pressure.

[0023] Optionally, the first control module and / or the second control module are configured to perform the monitoring based on a threshold value of the respective pressure. Alternatively or additionally, the monitoring can also be performed based on a temporal rate of change of the respective pressure.

[0024] Monitoring may include regularly, continuously, or randomly comparing the respective pressure or a temporal rate of change or a spatial gradient of the respective pressure with one or more tabulated values or other pattern or profile. Monitoring may also include comparing the first and second pressures, the first and third pressures, and / or the second and third pressures.

[0025] Embodiments also relate to a commercial vehicle comprising a twin-tyre axle with a first tire and a second tire and a single-tyre axle with a third tire, and having a device for monitoring a tire pressure of the type described above.

[0026] Optionally, the twin-tire axle can be a drive axle of the commercial vehicle. The drive axle can, in particular, be a rear axle.

[0027] Optionally, the single-tyred axle is a front axle, a push axle or a tag axle of the commercial vehicle.

[0028] Embodiments also relate to a method for monitoring tire pressure for a commercial vehicle having a dual-tire axle with a first tire and a second tire, and a single-tire axle with a third tire. The method comprises a first measurement, namely measuring a first pressure in the first tire, by a first pressure sensor. The method further comprises a second measurement, namely measuring a second pressure in the second tire, by a second pressure sensor. The method further comprises a third measurement, namely measuring a rotational speed of the third tire, by a rotational speed sensor. The method further comprises determining a third pressure based on the rotational speed. The method further comprises monitoring the first pressure, the second pressure, and the third pressure.

[0029] The first measurement, the second measurement, and the third measurement can be temporally correlated, e.g., performed together at a specific rhythm or in a specific sequence. The first and second measurements can each involve a telemetric transmission of measurement data. The third measurement can also involve querying a measured value of the third pressure via a CAN bus.

[0030] Embodiments also relate to a computer-readable storage medium which, for example, in the form of a software code or a machine language, comprises instructions which, when executed by a data processing machine, cause the machine to carry out the method described above.

[0031] Important aspects of the presented device and method can also be summarized as follows.

[0032] There are two known ways to monitor tire pressure: using pressure sensors in the wheel or by comparing wheel speeds. It has been shown that in commercial vehicles, particularly heavy commercial vehicles, the load capacity per tire can be lower and axle load fluctuations greater with twin-tyred axles than with single-tyred axles (especially with a single-tyred front axle). Furthermore, with twin-tyred axles, a pressure loss in a first tire can be influenced by the effects of the second tire or the load distribution. Overall, it has been shown that tire pressure monitoring via wheel speeds for twin-tyred axles cannot be carried out with a high degree of accuracy or reliability.

[0033] Dual-tire axles can occur on heavy commercial vehicles, particularly on the drive axle. However, tire pressure monitoring using pressure sensors is expensive, especially since sensors, antennas, and / or receivers must be installed separately. The device presented here represents a mixed installation. It monitors tire pressure on single-tire axles (such as a front axle, often also a push-axle or tag-axle) via wheel speeds. On dual-tire axles, the tire pressure is recorded and monitored by the device presented here using sensors. Both monitoring systems can be combined in a common control unit.

[0034] The embodiments of the present invention will be better understood from the following detailed description and the accompanying drawings of the various embodiments, which, however, should not be construed to limit the disclosure to the specific embodiments, but are for explanation and understanding only. Fig. 1 shows a commercial vehicle with an embodiment of the device according to the present invention. Fig. 2 shows steps of a corresponding method for monitoring tire pressure.

[0035] Fig. 1 schematically shows a horizontal cross-section through a commercial vehicle 1 with a device 100 for monitoring tire pressure. The commercial vehicle 1 is a towing vehicle of a vehicle combination with a twin-tyred axle 2 and a single-tyred axle 4. The twin-tyred axle 2 is a drive axle of the commercial vehicle 1, and the single-tyred axle 4 is a front axle of the commercial vehicle 1.

[0036] On a right side R of the commercial vehicle 1, the twin-tyred axle 2 carries a wheel with a first tire 11 on a first rim 12 and a wheel with a second tire 21 on a second rim 22. The single-tyred axle on the right side R of the commercial vehicle 1 carries a third wheel with a third tire 31 on a third rim 32.

[0037] The device 100 comprises a first pressure sensor 111, which is configured to measure a first pressure in the first tire 11, and a second pressure sensor 112, which is configured to measure a second pressure in the second tire 21. The first pressure sensor 111 and the second pressure sensor 112 are each configured to telemetrically transmit the first and second pressures, respectively. The pressure sensors 111, 112 can each be mounted inside the first tire 11 and the second tire 21, for example, on the first rim 12 and the second rim 22, respectively, or directly on the first tire 11 and the second tire 21, respectively.

[0038] The twin-tire axle 2 and the single-tire axle 4 each have a magnet wheel 3 on the right-hand side R of the commercial vehicle 1. The device 100 comprises a rotational speed sensor 113 configured to measure a rotational speed of the third tire 31 based on the corresponding magnet wheel 3 on the single-tire axle 4. In the present exemplary embodiment, a rotational speed sensor 13 is also mounted on the twin-tire axle 2 on the right-hand side R of the commercial vehicle 1. Measurement data from the rotational speed sensors 13, 113 can be made available to one or more additional devices of the commercial vehicle 1; in particular, these additional devices can be, for example, an anti-lock braking system or an electronic stability program.

[0039] The device 100 comprises a first control module 121, which is configured to receive and monitor the first pressure and the second pressure. The device 100 further comprises a second control module 122, which is configured to receive the rotational speed, to determine a third pressure in the third tire 31 from the rotational speed, and to monitor the third pressure. The two control modules 121, 122 exchange data and are configured to jointly output a warning, e.g., to a driver or to another device in the commercial vehicle 1, if the first, second, or third pressure is below or above a threshold value or is falling rapidly.

[0040] The control modules 121, 122 can be integrated into a control unit. However, they can also be parts of the additional devices or other components of the commercial vehicle 1. In particular, for example, the second control module 122 can be part of an anti-lock braking system or an electronic stability system. In other exemplary embodiments, the second control module 122 can also receive the data from the speed sensor 113 solely via the additional device; in particular, the second control module 122 can thus receive the speed only indirectly from the speed sensor 113.

[0041] The device 100 is also configured in the same way on a left side L of the commercial vehicle 1. There, the commercial vehicle 1 comprises, in particular, a first additional tire 11' and a second additional tire 21' on the twin-tire axle 2, and a third additional tire 31' on the single-tire axle 4. The device 100 comprises a first additional pressure sensor 111', which is configured to measure a first additional pressure in the first additional tire 11', and a second additional pressure sensor 112', which is configured to measure a second additional pressure in the second additional tire 21'. The first and second additional pressures are likewise transmitted telemetrically to the first control module 121. Furthermore, the device 100 comprises a further rotational speed sensor 113', which is configured to measure a further rotational speed of the third additional tire 31'. The further rotational speed is likewise transmitted to the second control module 122.The preceding description for the right side R of the commercial vehicle 1 may also apply to the left side L of the commercial vehicle 1.

[0042] In further embodiments, the commercial vehicle 1 can have further single, double (or multiple) tire axles, in which pressures in corresponding tires are determined by converting speeds from speed sensors (in the case of single-tire axles) or by direct pressure measurement (in the case of twin or multiple-tire axles).

[0043] Fig. 2shows steps of a corresponding method for monitoring tire pressure for a commercial vehicle 1 having a twin-tire axle 2 with a first tire 11 and a second tire 21, as well as a single-tire axle with a third tire 31. The method comprises a first measurement S110, in which a first pressure or pressure value in the first tire 11 is determined by a first pressure sensor 111. The method further comprises a second measurement S120, in which a second pressure or pressure value in the second tire 21 is determined by a second pressure sensor 112.

[0044] The method further includes a third measurement S130, in which a rotational speed of the third tire 31 is determined by a rotational speed sensor 113. The method also includes determining S140 a third pressure or pressure value from the rotational speed, and monitoring S150 the first pressure, the second pressure, and the third pressure.

[0045] The steps may be performed in a different sequence than that shown here. In particular, the frequencies at which the first measurement S110, the second measurement S120, and the third measurement S130 are performed may also differ from one another. LIST OF REFERENCE SYMBOLS

[0046] 1Commercial vehicle 2Twin-wheel axle 3Pole wheel 4Single-wheel axle 11, 11'First tire, first additional tire 12, 12'Rim of the first tire or the first additional tire 13, 13'Pressure sensors 21, 21'Second tire, second additional tire 22, 22'Rim of the second tire or the second additional tire 31, 31'Third tire, third additional tire 32, 32'Rim of the third tire or the third additional tire 100Device 111, 111'First pressure sensor, first additional pressure sensor 112, 112'Second pressure sensor, second additional pressure sensor 113, 113'Third pressure sensor, third additional pressure sensor 121First control module 122Second control module

Claims

1. Device (100) for monitoring a tire pressure for a utility vehicle (1), which has a dual-tired axle (2) with a first tire (11, 11') and a second tire (21, 21') as well as a single-tired axle (4) with a third tire (31) and a further third tire (31'), with: a first pressure sensor (111, 111'), which is configured to measure a first pressure in the first tire (11, 11'); a second pressure sensor (112, 112'), which is configured to measure a second pressure in the second tire (21, 21'); a rotational speed sensor (113'), which is configured to measure a rotational speed of the third tire (31'); a further rotational speed sensor (113'), which is configured to measure a rotational speed of the further third tire (31'); a first control module (121), which is configured to receive and monitor the first pressure and the second pressure; characterized by a second control module (122), which is configured to receive the rotational speed and the further rotational speed, to determine a third pressure in the third tire (31) based only on the rotational speed and the further rotational speed, and to monitor the third pressure.

2. Device (100) according to any one of the preceding claims, characterized in that the first control module (121) and the second control module (122) are combined into one control unit or are accommodated in separate control units.

3. Device (100) according to any one of the preceding claims, characterized in that the first control module (121) is configured to combine the first pressure and the second pressure into a combined pressure and to monitor the combined pressure.

4. Device (100) according to any one of the preceding claims, characterized in that the first control module (121) and / or the second control module (122) are configured to perform the monitoring based on at least one of the following: - a threshold value, - a rate of change over time, and to output a warning when predetermined values are exceeded.

5. Utility vehicle (1), comprising a dual-tired axle (2) with a first tire (11, 11') and a second tire (21, 21'); and a single-tired axle (4) with a third tire (31) and a further third tire (31'), characterized by the device (100) according to any one of the preceding claims.

6. Utility vehicle (1) according to claim 5, characterized in that the dual-tired axle (2) is a drive axle of the utility vehicle (1).

7. Utility vehicle (1) according to claim 5 or claim 6, characterized in that the single-tired axle (2) is a front axle, a pusher axle or a trailing axle of the utility vehicle (1).

8. Method for monitoring a tire pressure for a utility vehicle (1), which has a dual-tired axle (2) with a first tire (11, 11') and a second tire (21, 21') as well as a single-tired axle (4) with a third tire (31) and a further third tire (31'), with following steps: a first measurement (S110), by a first pressure sensor (111, 111'), of a first pressure in the first tire (11, 11'); a second measurement (S120), by a second pressure sensor (112, 112'), of a second pressure in the second tire (21, 21'); a third measurement (S130), by a rotational speed sensor (113, 113'), of a rotational speed of the third tire (31) and a further rotational speed of the further third tire (31'); characterized by: determining (S140) a third pressure, based only on the rotational speed and the further rotational speed; and monitoring (S150) the first pressure, the second pressure and the third pressure.