Patent Publication Number: US-2015061853-A1

Title: Repeater module for tire pressure monitoring system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to tire pressure monitoring technology, and more particularly to a repeater module for use in a TPMS (tire pressure monitoring system). 
     2. Description of the Related Art 
     To improve driving safety, a vehicle it may be equipped with a tire pressure monitoring system, as shown in  FIG. 1 . Through linking between an on-vehicle main unit  2  and a tire pressure sensor  4  in each tire  3  of the vehicle  1 , the on-vehicle main unit  2  can obtain the status data of each tire  3  so that the driver can know the current status of every tire  3  from a display interface  5  in the vehicle  1 , assuring a high level of driving safety. 
     A tire pressure monitoring system of this design has benefits and limitations. Normally, the settings of the on-vehicle main unit  2  and the display interface  5  are done in factory. The settings of either on-vehicle main unit  2  or display interface  5  are done to fit tires  3  of the vehicle. If the vehicle has four tires, the on-vehicle main unit  2  or display interface  5  can simply receive and display the status of these four tires. 
     In other words, the on-vehicle main unit  2  and the display interface  5  are configured to fit the original number of tires of the vehicle. If the number of tires of the vehicle is increased, the on-vehicle main unit  2  and the display interface  5  can neither accept the added tire nor provide the status information of the added tire. A vehicle driver may connect a trailer for towing. For example, a vehicle driver may connect a recreational vehicle, boat trailer or water friction trailer to a mother vehicle (powered vehicle). Even if the tires of the trailers are respectively equipped with a tire pressure sensor, the tire pressure sensors in the tires of the trailers still cannot be linked to the on-vehicle main unit in the mother vehicle, and the display interface in the mother vehicle cannot display the status of the tires of the trailers. In order to solve this communication problem, the on-vehicle main unit and the display interface must be modified. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a repeater module for TPMS (tire pressure monitoring system), which is capable of providing daughter vehicle tire status information. 
     It is another object of the present invention to provide a repeater module for TPMS (tire pressure monitoring system), which can provide the status information of attached tires without needing to modify the on-vehicle main unit. 
     It is still another object of the present invention to provide a repeater module for TPMS (tire pressure monitoring system), which facilitating installation and application. 
     To achieve these and other objects of the present invention, a repeater module of the invention is used in a tire pressure monitoring system and selectively installed in a mother vehicle or daughter vehicle of a tow truck for receiving a status signal from each daughter vehicle tire pressure sensor and providing a corresponding wireless signal to an on-vehicle main unit. The repeater module of the tire pressure monitoring system comprises a MCU, a memory unit electrically connected to the MCU and adapted for storing the ID code and communication protocol of at least one mother vehicle tire pressure sensor, a transmitter unit electrically connected to the MCU and adapted for transmitting a wireless signal to the on-vehicle main unit in the mother vehicle, a receiver unit electrically connected to the MCU and adapted for receiving a status signal from each daughter vehicle tire pressure sensor, and a power source electrically connected to the MCU to provide the repeater module with the necessary working electricity. 
     Preferably, the power source comprises a power cable connectable to the mother vehicle to obtain power supply from the mother vehicle. 
     Preferably, the repeater module of the tire pressure monitoring system further comprises an alarm unit electrically connected to the MCU and controllable by the MCU to give off an alarm signal. 
     Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing illustrating structure of a conventional tire pressure monitoring system. 
         FIG. 2  is a schematic drawing illustrating a repeater module installed in a tire pressure monitoring system in accordance with the present invention. 
         FIG. 3  is a system block diagram of the repeater module of the tire pressure monitoring system in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-3 , a repeater module  20  in accordance with the present invention is shown used in a TPMS (tire pressure monitoring system) and installed in a tow truck&#39;s mother vehicle  10  or daughter vehicle  30  for receiving status signals from daughter vehicle tire pressure sensors  31  and transmitting wireless signals to an on-vehicle main unit  11  of the TPMS in the mother vehicle  10 . 
     The repeater module  20  comprises: 
     a MCU (Micro Control Unit)  21 ; 
     a memory unit  22  electrically connected to the MCU  21  and controllable by the MCU  21  to store identification and communication protocol/communication protocol code of at least one mother vehicle tire pressure sensor  13 ; 
     a transmitter unit  23  electrically connected to the MCU  21  and adapted for processing the identification and communication protocol/communication protocol code of the at least one mother vehicle tire pressure sensor  13  been stored in the memory unit  22  into a wireless signal and then transmitting the wireless signal to the on-vehicle main unit  11  in the mother vehicle  10 ; 
     a receiver unit  24  electrically connected to the MCU  21  and adapted for receiving the status signals provided by the daughter vehicle tire pressure sensors  31 ; 
     a connection port  25  electrically connected to the MCU  21  for the connection of an external computer or setting tool that is operable to set or alter the identification and communication protocol/communication protocol code of the tire pressure sensors of the TPMS; 
     an alarm unit  26  electrically connected to the MCU  21  and controllable by the MCI  21  to give a visual or audio warning signal; 
     a switch  27  switchable to turn on/off the repeater module  20 ; and 
     a power source  28  electrically connected to the switch  27  for providing the repeater module  20  with the necessary electricity for working subject to the switching control of the switch  27 . The power source can be a battery, or a powder cable connected to a power socket in the motor vehicle  10 . 
     During application of the present invention, the repeater module  20  of the TPMS can be installed in the mother vehicle  10  and electrically connected to the power circuit of the mother vehicle  10  by the power source (power cable)  28 . For example, the repeater module  20  of the TPMS can be installed in the trunk of the mother vehicle  10  and electrically connected to the 12V power source of the mother vehicle  10 . After installation, turn on the repeater module  20  of the TPMS to receive the ID of every tire pressure sensor  31  in the daughter vehicle  30 , getting the repeater module  20  and every daughter vehicle tire pressure sensor  31  connected. Thereafter, let the ID and communication protocol obtained from any mother vehicle tire pressure sensor  13  be stored in the memory unit  22 . During operation of the TPMS, the repeater module  20  receives the status signal provided by every daughter vehicle tire pressure sensor  31  for reading by the MCU  21 . If the value of the status signal of every daughter vehicle tire pressure sensor  31  is within the normal range, the repeater module  20  simply keeps receiving the status signal from the daughter vehicle tire pressure sensors  31  without taking any other action. 
     However, if any daughter vehicle tire pressure sensor  31  exhibits an abnormal condition, for example, the status of “tire pressure too low” or “tire temperature too high”, the repeater module  20  will receive an abnormal status signal from the respective daughter vehicle tire pressure sensor  31 . The abnormal status signal will then be interpreted by the MCU  21 . After interpretation, the MCU  21  will drive the transmitter unit  23  to transmit a corresponding wireless signal subject to the ID and communication protocol of the mother vehicle  10  to the on-vehicle main unit  11  in the mother vehicle  10 , and at the same time, the alarm unit  26  will be driven by the MCU  21  to give off a visual or audio alarm signal. At this time, a display interface  12  in the mother vehicle  10  will give an indication, including the abnormal status of the respective mother vehicle tire pressure sensor  31 . Thus, the driver can know the abnormal status of the daughter vehicle without altering the on-vehicle main unit and the display interface, enhancing driving safety. 
     Further, if the daughter vehicle  30  is to be detached from the mother vehicle  10 , directly dismount the power source (power cable)  28  or turn off the switch  27  of the repeater module  20 . At this time, the repeater module  20  is stopped from working, and the on-vehicle main unit  11  can simply receive signals provided by the mother vehicle tire pressure sensors  13 . 
     In the TPMS of the present invention, the repeater module  20  and the on-vehicle main unit  11  use the same communication protocol; the on-vehicle main unit  11  and the mother vehicle tire pressure sensors  13  use the same communication protocol. Thus, signals provided by the repeater module  20  are compatible to and directly receivable by the on-vehicle main unit  11 . Therefore, the application of the present invention does not need to modify the on-vehicle main unit  11 . 
     Further, by means of the connection port  25 , the invention can be connected to an external setting tool for the modification of the communication protocol and ID codes. Further, through the receiver unit  24 , the invention can receive a signal from an external setting tool to modify the communication protocol and ID codes. 
     In case of any daughter vehicle tire abnormality, the alarm unit  26  of the repeater module  20  of the TPMS and the display interface  12  in the mother vehicle  10  will simultaneously give off an alarm. If a mother vehicle tire abnormality occurs, only the display interface  12  will give off an alarm, and the alarm unit  26  of the repeater module  20  of the TPMS will give no signal. Thus, subject to this signaling difference, the driver can discriminate between a mother vehicle tire abnormality and a daughter vehicle tire abnormality. 
     Further, the frequency of the signal provided by the transmitter unit  23  of the repeater module  20  of the TPMS and the frequency of the signal received by the receiver unit  24  can be same. Further, in order to prevent the on-vehicle main unit in the mother vehicle from receiving the status signal of each daughter vehicle tire pressure sensor in causing confusion, the mother vehicle tire pressure sensors and the daughter vehicle tire pressure sensors can be configured to operate on different frequencies. For example, the mother vehicle tire pressure sensors can be configured to operate on 315 MHz, and the daughter vehicle tire pressure sensors can be configured to operate on 433 MHz. Thus, the on-vehicle main unit can be configured to receive 315 MHz signals only, preventing confusion. In this case, the repeater module is configured to receive 433 MHz status signals and to transmit 315 MHz wireless signals.