Patent Application
20130321139
The invention relates to a tire pressure monitoring system (TPMS) for four-wheel passenger vehicle, particularly, relates to a method and device of TPMS for receiving and processing the tire pressure signals in order to realize tire positioning.
Tire pressure monitoring system (TPMS) is used mainly for monitoring the pressure and temperature of tires of a vehicle, for warning in advance the potential danger caused by the pressure and temperature of the tires to ensure traffic safety. With the development of the TPMS technology, the requirement for the TPMS is becoming higher and higher. It is required that not only the pressure and temperature information of the tires can be displayed but also the positions of the tires can be indicated accurately. Therefore, higher requirements are put forward for the tire positioning technology.
Currently, there are the following schemes in the tire positioning area:
(1) Fixed code form: in said positioning technology, the entire identification (ID) code information of the transmitter is stored in the receiving and displaying module in read-only form when the product is outputted from the factory, and it cannot be modified when it is used. The scheme is rather simple, however, the inadequacy is: the transmitter should not be installed at wrong position, otherwise the identification may be confused while using; at the same time, after the transmitting module being damaged, the user can only solve the problems by sending the product to the manufacturer.
(2) Interface inputting form: in said positioning technology, the ID information of each transmitting module is printed on the outer package or on the product, after installing, changing the tire position or the transmitting module being damaged, the ID information can be inputted into the receiving and displaying module by the keys to perform correct identification.
The inadequacy of said technology is: because the length of ID is 16 bits or 32 bits, the input procedure is rather complicated, wrong code group may be inputted by the user; and it is unexpected that installing so many keys on a vehicle having many instruments, it makes the layout inconvenience.
(3) Low frequency wakeup form: in said positioning technology, the near-field effect of the low frequency (LF) signal (such as a signal of 125 KHz) is used, and a LF antenna device is installed near each tire, the transmitting detection module of the corresponding tire can be triggered individually by controlling the LF antenna device, then the identification code can be transmitted by the triggered transmitting detection module as a radio frequency (RF) signal, and the identification code of the corresponding tire TPMS module can be obtained by the receiving module via the RF signal, thereby the position of the tire can be determined automatically.
The inadequacy of said technology is:
1. If a LF antenna is used, then the workload of installing the LF antenna and wiring is large, and the cost is high;
2. Specific devices are used, and each tire may be operated manually, thereby the operation is troublesome;
3. Various interferences exist because the electromagnetic environment on the vehicle is complicated, and the low frequency signal may be interfered, it causes the positioning failure.
One object of the invention is to provide a low cost tire positioning device which can position the tires conveniently.
Another object of the invention is to provide a method and device for receiving and processing the tire pressure signals by using said tire positioning device.
The tire positioning device provided in the invention comprises a first directional antenna, a second directional antenna, an amplifier and a field strength determination module. The first directional antenna can be positioned near one of the front wheels of a vehicle, and its orientation points to another front wheel of said vehicle. The second directional antenna can be positioned near one of the rear wheels of said vehicle, said rear wheel and said one of the front wheels are arranged diagonally, and the orientation of the second directional antenna points to another rear wheel of said vehicle. The amplifier can be connected to the first directional antenna and the second directional antenna to amplify the transmitter signals detected by the first directional antenna and the second directional antenna, respectively. The field strength determination module can be connected to the amplifier for comparing the electric field strength of the transmitter signals received by the first directional antenna and the second directional antenna to determine the tire positions where the transmitters are installed.
In said tire positioning device, said amplifier and said field strength determination module are combined in the receiving and displaying module of the TPMS of said vehicle.
In said tire positioning device, the distance between said first directional antenna and said one of the front wheels of said vehicle is less than 1 meter.
In said tire positioning device, the distance between said second directional antenna and said one of the rear wheels of said vehicle is less than 1 meter.
In said tire positioning device, the signals transmitted by said transmitters are radio-frequency signals.
A tire pressure signal receiving and processing device provided in the invention comprises a first directional antenna, a second directional antenna, an amplifier, a signal converter and a micro-controller. The first directional antenna can be positioned near one of the front wheels of a vehicle, and its orientation points to another front wheel of said vehicle. The second directional antenna can be positioned near one of the rear wheels of said vehicle, said one of the rear wheels and said one of the front wheels are arranged diagonally, and the orientation of the second directional antenna points to said another rear wheel of said vehicle. The amplifier can be connected to the first directional antenna and the second directional antenna to amplify the pressure signals in radio form transmitted from the transmitters and detected by the first directional antenna and the second directional antenna, respectively. The pressure signals in the radio form can be converted to electric field strength signals by the signal converter. The converted electric field strength signals of the respective transmitters can be received by the micro-controller, and the tier positions where the transmitters are positioned can be determined based on the magnitude of the electric field strength signals of the respective transmitters.
In said tire positioning device, said amplifier and said signal converter can be disposed internally in a demodulator, said pressure signals can also be demodulated by said demodulator and sent to said micro-controller for processing.
A tire pressure signal receiving and processing method proposed in the invention comprises the following steps: disposing a first directional antenna near one of the front wheels of a vehicle with its orientation pointing to another front wheel of said vehicle; disposing a second directional antenna near one of the rear wheels of said vehicle, said one of the rear wheels and said one of the front wheels being disposed diagonally, and its orientation pointing to said another rear wheel of said vehicle; amplifying the pressure signals in radio form transmitted from the transmitters and detected by the first directional antenna and the second directional antenna, respectively; converting the pressure signals in the radio form to electric field strength signals, and receiving the converted electric field strength signals of the respective transmitters, and determining the tire positions where the respective transmitters are disposed based on the magnitudes of the electric field strength signals of the respective transmitters.
Because the above technical scheme is used in the invention, the electric field strength can be detected by using the diagonal antennas, the electric field strength data can be processed by specific algorithm, and the tire positions can be determined. Therefore, by comparing with the prior art, the following notable advantages are achieved by the invention:
(1) The installation, and maintenance are easy and quick. Particularly, the transmitters need not be distinguished during installation, they can be installed randomly, and so as the maintenance;
(2) Said technical scheme detects the magnitudes of the field strength, no any hardware must be added and no any increased cost;
(3) It is versatile, and it can be used for various four-wheel vehicles;
(4) The operation is simple.
The features and performances of the invention can be further described by the following embodiments and the drawings.
In order to enable the TPMS to position the tires easily and quickly, a tire positioning device of the invention is described in the following embodiment. The tire positioning device measures electric field strength to distinguish different transmitters and tires thereof.
The main function of the directional antennas 12a, 12b is to measure inductively the electric field strength of the signals transmitted by the respective transmitters A, B, C, and D. Furthermore, the sensor sensitivity of the directional antennas 12a, 12b at a specific direction is larger than that at other directions.
In order to distinguish the electric field strength of four transmitters, two directional antennas 12a, 12b can be disposed diagonally. Specifically, the directional antenna 12a can be installed at a position within a range of about 1 M from the transmitter A of the left front wheel, and the orientation points to the transmitter B of the right front wheel at the opposite side. The directional antenna 12b can be installed at a position within a range of 1M from transmitter C of the right rear wheel, and the orientation points to the transmitter D of the left rear wheel at the opposite side. However, the directional antennas 12a, 12b are omni-directional in the near-field range, therefore the electric field strength of the transmitters A, D measured by them, respectively, is still large.
The two directional antennas 12a, 12b are connected to the amplifier 14. The main function of the amplifier 14 is to amplify the signals detected by the directional antennas according to a fixed magnification, and it is of benefit to the subsequent data processing. The main function of the field strength determination module 16 is to compare the electric field strength of the transmitter signals received by the directional antennas 12a, 12b and to determine the tire positions where the transmitters are disposed. In this embodiment, the modulation of the transmitter signals is not involved, instead, only the measure of the signal strength is carried out.
For example, it is set that:
The electric field strength of the transmitters A, B, C, and D measured by the directional antenna 12a is E1A, E1B, E1C, and E1D, respectively;
The electric field strength of the transmitters A, B, C, and D measured by the directional antenna 12b is E2A, E2B, E2C, and E2D, respectively.
For the same reason, it can be decided from the directional antenna 12b that the electric field strength E2C detected by the directional antenna 12a is the largest, it is from the transmitter C of the right rear wheel, the field strength E2D from the transmitter D of the left rear wheel, is the second largest .
In practical application, said amplifier 14 and field strength determination module 16 can be incorporated into the receiving and displaying module of the TPMS to form a receiving and processing device for the tire pressure signals. As shown in
The demodulator 21 can comprise an amplifier 21a for measuring the field strength and a signal converter 21b. The amplifier 14 connects with two directional antennas 12a, 12b, the main function of the amplifier 21a is to amplify the signals, such as the pressure signals in the radio form (for example, RF signals), detected by the directional antennas according to a fixed magnification, and it is of benefit to the subsequent data processing. The main function of the signal converter 21b is to perform the data quantization of the signals measured by the directional antennas in order to produce the electric field strength signals having distinguishable field strength magnitudes. The magnitudes of the electric field strength signals can be compared by the MCU 22 thereby the transmitter positions corresponding to the respective electric field strength can be determined. The function of the field strength determination module can be implemented collectively with the signal converter 21b and MCU 22.
The RF signals received by the directional antennas 12a, 12b are transmitted to the receiving and displaying module 20, the electric field strength values are transmitted to the MCU 22 by the demodulator 21 of the receiving and displaying module 20 via RSSI port, then the data can be processed by the MCU 22 based on specific algorithm for positioning the tires. On the other hand, RF signals are amplified, frequency selected, detected, demodulated by the demodulation function module 21c of the demodulator 21 to extract the pressure, temperature, and state information of the sensors, and those are processed by the MCU 22, and finally, displayed on the display 23.
In summary, In the embodiment of the invention, the electric field strength can be measured by utilizing diagonal directional antennas, and the field strength data are processed by using specific algorithm thereby the position of the tires can be decided. The advantages of the scheme are as follows:
(1) The installation, and maintenance are easy and quick. Particularly, the transmitters need not be distinguished during installation during installation, they can be installed randomly, and so as the maintenance;
(2) Said technical scheme detects the magnitude of the field strength, no any hardware must be added and no any increased cost;
(3) It is versatile, and it can be used for various kinds of four-wheel vehicles;
(4) The operation is simple. Although the invention has been disclosed by the preferred embodiment as above, but it is not a limitation to the invention, and various modifications and improvements can be made by those skilled in the art without departing the spirit and scope of the invention, therefore, the protection scope of the invention should be within the scope as defined in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010516067.2 | Oct 2010 | CN | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CN11/80253 | 9/28/2011 | WO | 00 | 8/21/2013 |
