WO2009027233A1

WO2009027233A1 - Device and method for the reduction of the radio distance in its sensors

Info

Publication number: WO2009027233A1
Application number: PCT/EP2008/060634
Authority: WO
Inventors: Peter Rieth; Ulrich STÄHLIN
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2007-08-29
Filing date: 2008-08-13
Publication date: 2009-03-05

Abstract

The invention relates to a device and a method for the reduction of the radio distance in an ITS sensor (3), which is integrated into a tire (1) of a motor vehicle (2) for detecting dynamic driving data, and which is connected to a wireless communication unit (4) installed in the motor vehicle (2), said unit transmitting the dynamic driving data received from the ITS sensor (3) to an analysis unit (9) for signal processing, wherein the communication unit (4) is an integral part of an electromechanical braking unit (5) locally installed on the tire (1).

Description

Device and method for reducing the radio distance for ITS sensors

The present invention relates to a device and a method for reducing the radio distance in an ITS sensor (Intelligent Tire Sensor), which is integrated for detecting dynamic driving data in a tire of a motor vehicle, and is connected to a wireless communication unit installed by the motor vehicle which forwards the dynamic driving data received from the ITS sensor to an evaluation unit for signal processing.

The field of application of the present invention extends primarily to motor vehicle technology, in particular passenger vehicle technology. A driving dynamics system of a motor vehicle requires sensor-technically determined input data for controlling the driving dynamics of the vehicle, which provide information about the current vehicle condition. Such data come, inter alia, from ITS (intelligent tire sensor) sensors, which are integrated in a tire of the motor vehicle and there primarily measure the tire pressure or other driving dynamics data to the driving dynamics system, for example, to implement an ESP function To make available. Other parameters, such as the deformation of the tire can be determined using modern ITS sensors.

Since the evaluation and further use of the thus measured vehicle dynamics data usually takes place inside the motor vehicle, a transmission of the measurement data of the rapidly rotating tire to the stationary relative to this evaluation unit. Since data transmission by means of electrical connection lines is possible only with a high design effort and extremely susceptible to wear and external influences, wireless communication generally takes place.

EP 1 227 944 B1 discloses a generic device for wireless communication between an ITS sensor arranged in a tire and an evaluation unit mounted on the side of the vehicle. The evaluation unit evaluates the shift values of the tire detected by the ITS sensor and calculates therefrom vehicle dynamics data such as the forces acting on the tire, the tire pressure, the rotational speed or the speed of the measuring point and its acceleration. In addition, it is proposed to arrange the evaluation unit directly next to the ITS sensor between rim flanges of the tire on the rim inside the tire. In this case, the output signals of the ITS sensor or of the evaluation device are coupled in a manner known per se without contact into an assigned wireless communication unit in the vehicle. The vehicle-side communication unit is connected to a control unit, which influences the forces acting on the tire due to the output signals of the evaluation unit by engaging in the engine or brake system.

EP 1 681 660 A1 discloses another known device for the wireless communication of an ITS sensor with a vehicle-side communication unit. In this solution, a plurality of ITS sensors are arranged equidistantly from each other along the tire circumference. Each ITS sensor is equipped with a wireless communication interface which communicate with a likewise within the tire, preferably here but the rim side arranged base station. The base station collects the data from all the tire-integrated ITS sensors, processes them and sends the processed vehicle dynamics data wirelessly to a vehicle control unit integrated in the vehicle chassis. Disadvantages of the above-discussed prior art solutions for the wireless communication of ITS sensors are the usually long radio links between the tire and the communication unit installed by the vehicle chassis. Due to the long radio link may lead to disruption of communication in unfavorable reception conditions, which exist especially in bad weather conditions. So far, this can only be counteracted by increasing the radio performance of the wireless communication, which in turn results in an increased energy requirement, which can be provided by the ITS sensors only by a battery of larger capacity or correspondingly strong transponder electronics.

It is therefore an object of the present invention to provide a device for reducing the radio distance in an ITS sensor, with which a reliable transmission of the sensor technology detected data without increasing the energy consumption is possible.

The object is achieved on the basis of a device according to the preamble of claim 1 in conjunction with its characterizing features. Technically, the object is achieved by claim 9. The respective dependent dependent claims give advantageous developments of the invention again.

The invention includes the technical teaching that the motor vehicle side communication unit is part of an electromechanical brake unit mounted close to the tire.

In other words, according to the invention, the communication unit representing the receiver for the ITS sensor is integrated in an electromechanical brake unit (EMB) which is able to build up a reliable communication connection to the at least one ITS sensor due to the proximity to the tire for braking purposes. - A -

Since the electromechanical brake unit is already very close to the wheel in the vehicles equipped therewith and requires a data connection to the motor vehicle, this data connection can also be used for forwarding the data acquired by the ITS sensor according to a further improvement of the invention. Further signal-processing can then take place by an electronic evaluation unit arranged centrally in the motor vehicle, which according to another measure improving the invention can also be part of an electronic brake control of the motor vehicle. The advantage of this embodiment is that a modern electronic brake control, for example, to implement an ESP (Electronic Stability Program) function as input data requires the vehicle dynamic data determined by an ITS sensor.

An electromechanical brake (EMB), in which the solution according to the invention is implemented, produces, in accordance with its main function, the braking pressure required for braking the motor vehicle by means of an electric motor which actuates a caliper which cooperates with a brake disc of the wheel for the purpose of braking. This also known as wheel brake module electromechanical brake unit consists mainly of an electronic control unit, an electric motor and a transmission. Electric motor and gearbox form the so-called actuator, which generates the tensile forces in the caliper. Usually, four actuators of a motor vehicle are able to provide forces of up to several tons within milliseconds. The power demand for the EMB is quite high and would overwhelm the current 12 volt power grids of motor vehicles. Therefore, an EMB is designed for a higher operating voltage. This voltage is the EMB but not directly obtained from the vehicle battery. Additional accumulators usually buffer current spikes. The shared power supply in the vehicle can thus satisfy the power requirements of the actuators, without burdening the actual on-board electrical system. Even in an emergency, the driver is with equipped with additional accumulators, because the high storage capacity allows even the onward journey, if the generator of the motor vehicle can no longer supply charging current to the accumulators because of a defect. In addition, such a design of the EMB also corresponds to today's division of a hydraulic brake system into two separate circuits.

An EMB, which can be further extended without much effort to an electric parking brake (EPB), promises shortened stopping distances due to the fast response of the brakes. It was found that the electronic brake pedal, its favorable, ergonomic arrangement and the low possible operating forces a time advantage of half a second can be realized, which significantly shortens the stopping distance. If a defect in the electrical signal transmission between the driver and the wheel brake, the pedal travel is no longer, the pedal force remains unchanged. This allows the pedal module, in contrast to the purely mechanical-hydraulic or an electro-hydraulic brake move closer to the bulkhead of the vehicle chassis. More space in the interior and reducing the risk of injury in the footwell are beneficial concomitants. EMB's allow braking functions such as partial braking (EBV, ESBS), full braking (ABS), brake intervention (BASR), yaw moment control (GMR) or brake assistance (BA).

Advantageously, the connection between the at least one tire-integrated ITS sensor and the wireless vehicle-side communication unit should be configured as a short-range communication link. In particular, this is the Bluetooth standard. However, it is also conceivable to establish a connection via WLAN standard or ZigBee standard. If the ITS sensor is designed as a passive transponder, a communication via RFID (radio frequency identification) is recommended. Preferably, however, the ITS sensor used in the context of the present invention is embodied as an active, eg battery-operated or radio-frequency module equipped with a microgenerator. The capacity of the integrated battery in the ITS sensor is usually well beyond the normal life of a tire for short-range communications. Due to the own operating voltage supply for the ITS sensor, a continuous short-range communication can be carried out.

Within the scope of the present invention, it is also conceivable to integrate at least one wear detection sensor in the tire, in addition to the above-explained ITS sensor, which is preferably designed in the manner of a passive transponder explained above. Because for the purpose of wear detection of a tire, the usually discontinuous operated transponder technology is sufficient. Such a wear detection sensor is incorporated into the material of the tire during manufacture. Once the wear detection sensor is cleared and finally severed, it is no longer able to send data to an associated transponder receiver, indicating that the tire has shut down. If such transponder receivers are installed at different height levels in the tire, which are traversed one after the other, even a graded wear detection can take place.

The transponder receiver assigned to the wear detection sensor on the vehicle side is likewise preferably a component of the electromechanical brake unit in order to allow a short radio distance for this purpose as well. As a result, the wear detection sensor designed as a passive transponder can be activated and read with relatively low electrical energy.

According to another measure improving the invention, it is proposed that both the dynamic data of the at least one ITS sensor received by the wireless communication unit and, if appropriate, those received by the transponder Wear condition data within the near-wheel electro-mechanical brake unit are converted into serial data. This serial data can be transmitted by data bus to the central evaluation unit in the motor vehicle, which is preferably integrated in the EBS (electronic brake control). By this signal processing measure, the most provided anyway in a motor vehicle data bus communication between the components of an electronic braking system for the purpose of the invention can be used without additional connecting lines are required for this purpose.

Further, measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the single figure.

The figure shows a schematic representation of a device for reducing the radio distance in an ITS sensor.

The illustration in the figure is schematic and not to scale.

According to FIG. 1, an ITS sensor 3 is integrated in a tire 1 of a motor vehicle 2. The ITS sensor 3 detects the tire pressure as well as the external forces acting on the tire 1 and transmits these vehicle dynamics data by radio to a wireless communication unit 4 permanently installed on the part of the motor vehicle 2.

The wireless communication unit 4 on the part of the motor vehicle 2 is here an integral part of an electromechanical brake unit 5 of the motor vehicle 2. In this way, a very small radio distance between the ITS sensor 3 and the communication unit 4 is achieved. Because the electromechanical brake unit 5 is in the region of the hub 6 of the Motor vehicle 2 arranged and generated from electrical energy by caliper for a brake disc 8 required for braking braking force.

The wireless communication unit 4 forwards the driving dynamics data received from the ITS sensor 3 to an evaluation unit 9 installed centrally in the motor vehicle for signal processing. Here, the communication unit 4 uses an electrical connection line 10, which is usually provided for controlling the electromechanical brake unit 5 via data bus. The evaluation unit 9 is in this embodiment part of an electronic brake control of the motor vehicle 2 and determined based on the driver's braking request and input side supplied sensor signals that also contain the driving dynamics data of the ITS sensor 3, the control signal for the electromechanical brake unit 5. This driving dynamics functions, as ESP, ABS (anti-lock braking system) into account.

In the mounted on the rim 7 tire 1, a wear detection sensor 11 is integrated in addition to the ITS sensor 3, which is designed in the manner of a passive transponder and is supplied so far from the outside via electromagnetic radiation with the required operating energy. The wear detection sensor 11 is integrated below the tread of the tire 1 and is destroyed as soon as it is cleared. A failure of the wear detection sensor 11 is interpreted in terms of control technology as reaching the wear limit of the tire 1. Trained in the manner of a passive transponder wear detection sensor 11 is activated and read by a likewise integrated by the electromechanical brake unit 5 transponder receiver 12.

By contrast, the ITS sensor 3 in this exemplary embodiment is a battery-operated radio module. The battery integrated in the ITS sensor 3 is dimensioned with its capacity for a continuously long operation over the normal service life of the tire 1 is ensured. Thanks to the very small radio distance to the communication unit 4, the inventive ITS sensor 3 requires a fairly low operating energy. The radio distance is ensured via a short-range communication connection, here according to the Bluetooth standard.

The invention is not limited to the embodiment described above. In particular, other suitable means for wireless short-range communication between ITS sensor 3 and vehicle-side communication unit 4 can be used.

LIST OF REFERENCE NUMBERS

tires

motor vehicle

ITS sensor

communication unit

brake unit

wheel hub

rim

brake disc

evaluation

connecting line

Wear detection sensor

transponder receiver

Claims

1. A device for reducing the radio distance in an ITS sensor (3), which is integrated for detecting dynamic driving data in a tire (1) of a motor vehicle (2), and with a part of the motor vehicle (2) installed wireless communication unit (4 ), which forwards the dynamic driving data received by the ITS sensor (3) to an evaluation unit (9) for signal processing, characterized in that the communication unit (4) is part of an electromechanical brake unit (5) mounted close to the tire (1). is.

2. Device according to claim 1, characterized in that the dynamic data received by the communication unit (4) via the electrical connection line (10) of the electromechanical brake unit (5) to the centrally arranged evaluation unit (9).

3. Device according to claim 1, characterized in that the connection between the ITS sensor (3) and the wireless communication unit (4) is designed as a short-range communication connection.

4. Device according to claim 3, characterized in that the short-range communication connection is selected from a group comprising: Bluetooth standard, RFID, WLAN, ZigBee.

5. Device according to claim 1, characterized in that the ITS sensor (3) is designed as a battery-operated or microgenerator-operated radio module.

6. Device according to claim 1, characterized in that the evaluation unit (9) is part of an electronic brake control (3) of the motor vehicle (2) whose ESP function uses the vehicle dynamics data of the ITS sensor (3) as an input signal.

7. Device according to claim 1, characterized in that in the tire (1) in addition at least one wear detection sensor (11) is integrated, which is designed in the manner of a passive transponder.

8. Device according to claim 7, characterized in that the electromechanical brake unit (5) comprises a transponder receiver (12) for activating and reading out the at least one wear detection sensor (11).

9. A method for reducing the radio distance in an ITS sensor (3), which is integrated for detecting driving dynamics data in a tire (1) of a motor vehicle (2), and with a part of the motor vehicle (2) installed wireless communication unit (4 ), from where the vehicle dynamic data received by the ITS sensor (3) are forwarded to an evaluation unit (9) for signal processing, characterized in that the vehicle dynamics data are transmitted by a wireless communication unit (4) to a localized tire (1). mounted electromechanical brake unit (5) are received.

10. The method according to claim 9, characterized in that the wireless communication unit (4) received driving dynamics data of the at least one ITS sensor (3) in the near-wheel electromechanical brake unit (5) are converted into serial data, and via the connecting line ( 10) are transmitted via data bus to the central evaluation unit (9).