JP2016013745A - Tire air pressure monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire air pressure monitoring system capable of decreasing a number of components.SOLUTION: By using a remote key 12, when the operation of the remote key 12 is specified operation, an alarm threshold Th in a type air pressure monitoring system is initialized. Therefore, there is no need of being provided with an initialization switch, and wiring connected from the initializing switch to a received 3 which is an ECU for monitoring the tire air pressure also becomes unnecessary. Consequently, a number of components can be decreased, and a cost can be reduced.

Description

  The present invention relates to a tire pressure monitoring system that monitors a decrease in tire pressure.

  2. Description of the Related Art Conventionally, there is a tire air pressure detection device that monitors a decrease in tire air pressure and warns a user when it is detected that the tire air pressure has decreased (see, for example, Patent Document 1). In this tire pressure detection device, a predetermined alarm threshold value (for example, a value that is 20% lower than the current tire pressure) is set for the current tire pressure detected last time, and the tire pressure detected thereafter sets the alarm threshold value. Below that, it is detected that the tire pressure has decreased. The alarm threshold value set at this time is automatically set based on the tire pressure stored at the time of the previous calculation by an electronic control device (hereinafter referred to as ECU) for monitoring the tire pressure. Is done.

  However, when the user adjusts the tire pressure by, for example, newly refilling the tire, there is a possibility that the current tire pressure, which is the reference for setting the alarm threshold, changes, making it impossible to monitor the tire pressure appropriately. For this reason, an initialization switch for instructing initialization to the tire pressure monitoring ECU is provided, and the alarm threshold is initialized when the user presses the initialization switch. Based on the newly detected tire pressure An alarm threshold is set.

JP 2007-15491 A

  As described above, the alarm threshold can be initialized by providing an initialization switch for initializing the alarm threshold. However, the initialization switch must be provided, and the initialization switch is used for tire pressure monitoring. Wiring connecting to the ECU is also required. For this reason, there is a problem that the number of parts increases and the cost increases.

  In view of the above points, an object of the present invention is to provide a tire pressure monitoring system capable of further reducing the number of parts.

  In order to achieve the above object, the tire pressure monitoring system according to any one of claims 1 to 3 is provided for each of a plurality of wheels (5a to 5d) including a tire, and relates to the tire pressure of each of the plurality of wheels. A sensing unit (21) that outputs a detection signal, a first control unit (22) that performs signal processing on the detection signal output from the sensing unit and creates a frame stored as data related to tire air pressure, and radio wave transmission that transmits the frame A transmitter (2) having a portion (23), a radio wave receiver (32) provided on the vehicle body side for receiving a frame, and data on tire pressure stored in the received frame, A second control unit that detects the tire air pressure and determines that the tire air pressure decreases when the detected tire air pressure is lower than an alarm threshold (Th). 3) and a switch for instructing door locking / unlocking control which is control of unlocking and locking of a door provided in the vehicle, and based on the operation of the switch by the user And a portable device (12) for transmitting a door lock signal or a door unlock signal.

  In such a configuration, when the second control unit receives the door lock signal or the door unlock signal output from the portable device, the determination unit (S100) determines whether or not the switch operation is a specific operation. , And an initialization means (S110) for initializing the alarm threshold when the switch operation is a specific operation.

  Thus, the alarm threshold value in the tire pressure monitoring system can be initialized by operating the portable device. This eliminates the need for a separate initialization switch and eliminates the need for wiring from the initialization switch to a receiver corresponding to an ECU for monitoring tire pressure. Therefore, the number of parts can be reduced.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

It is the figure which showed schematic structure of the tire pressure monitoring system and remote key system concerning 1st Embodiment of this invention. It is a figure which shows the block configuration of the transmitters 2a-2d. 2 is a block diagram illustrating a receiver 3. FIG. It is the flowchart which showed the detail of the alarm threshold value initialization process which the control part 33 performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 corresponds to the front of the vehicle 1, the downward direction of the paper corresponds to the rear of the vehicle 1, and the horizontal direction of the paper corresponds to the horizontal direction of the vehicle.

  The tire pressure monitoring system according to the present embodiment performs tire pressure monitoring in part with a remote key system used in a keyless entry or smart entry (registered trademark) system.

  As shown in FIG. 1, the tire pressure monitoring system includes transmitters 2 a to 2 d, a receiver 3, and a display 4. The remote key system includes a body ECU 10, a door lock actuator 11, and a remote key 12. In this embodiment, the receiver 3 for monitoring the tire air pressure receives a door lock / unlock signal in the remote key system. Are also used. That is, the receiver 3 is shared by the tire pressure monitoring system and the remote key system.

  As shown in FIG. 1, the transmitters 2 a to 2 d are attached to the wheels 5 a to 5 d in the vehicle 1, and detect the air pressure of tires attached to the wheels 5 a to 5 d and detect the detection results. The signal data is stored in a frame and transmitted. The receiver 3 is attached to the vehicle body 6 side of the vehicle 1 and receives frames transmitted from the transmitters 2a to 2d, and performs various processes and calculations based on the detection signals stored therein. To monitor tire pressure. The receiver 3 also plays a role of receiving a door lock / unlock signal transmitted from the remote key 12 and transmitting it to the body ECU 10.

  As shown in FIG. 2A, the transmitters 2a to 2d are configured to include a sensing unit 21, a control unit (first control unit) 22, a radio wave transmission unit 23, a battery 24, and an antenna 25. Each unit is driven based on the power supply from the battery 24.

  The sensing unit 21 includes, for example, a diaphragm-type pressure sensor 21a, a temperature sensor 21b, and the like, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the tire internal temperature, and outputs the detection signal to the control unit 22. I tell you.

  The control unit 22 is configured by a known microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and executes predetermined processing according to a program stored in a memory in the ROM or the like. The memory in the control unit 22 stores ID information including identification information unique to the transmitter for identifying each of the transmitters 2a to 2d and identification information unique to the vehicle for identifying the host vehicle.

  The control unit 22 receives the detection signal output from the sensing unit 21, processes the signal and processes it as necessary, and then includes the ID information of each of the transmitters 2 a to 2 d as data indicating the detection result in the frame. Store the frame and send the frame to the radio wave transmitter 23.

  The radio wave transmission unit 23 functions as an output unit that transmits the frame transmitted from the control unit 22 through the antenna 25 to the receiver 3 as an RF radio wave. The process of sending a signal from the control unit 22 to the radio wave transmission unit 23 is set to be executed for each predetermined periodical transmission according to the program. Since it is impossible to determine whether the ignition switch (IG) is on or off on the transmitters 2a to 2d side, frame transmission is basically performed at every predetermined periodic transmission cycle.

  The battery 24 supplies power to the sensing unit 21, the control unit 22, etc., and receives power supply from the battery 24, collects data related to tire air pressure in the sensing unit 21 and controls the control unit 22. Various calculations are executed.

  The transmitters 2a to 2d configured as described above are attached to air injection valves in the wheels of the wheels 5a to 5d, for example, and are arranged so that the sensing unit 21 is exposed to the inside of the tire. Thereby, the transmitters 2a to 2d detect the tire air pressure of the corresponding wheels, and transmit frames at predetermined intervals through the antennas 25 provided in the transmitters 2a to 2d.

  Further, the receiver 3 shown in FIG. 2B constitutes an ECU for monitoring tire air pressure, and operates based on power supply from a battery or the like. Specifically, the receiver 3 includes an antenna 31, a radio wave receiving unit 32, and a control unit 33.

  The antenna 31 is for receiving a frame sent from each of the transmitters 2 a to 2 d and a door lock / unlock signal from the remote key 12. In this embodiment, the antenna 31 is a single common antenna that collectively receives the door lock / unlock signals sent from the transmitters 2 a to 2 d and the remote key 12. 6 is fixed.

  When the radio wave receiving unit 32 receives a frame transmitted from each of the transmitters 2 a to 2 d and a door lock / unlock signal sent from the remote key 12 by the antenna 31, it inputs it and sends it to the control unit 33. It functions as a part.

  The control unit (second control unit) 33 is configured by a known microcomputer having a CPU, ROM, RAM, I / O, and the like, and executes various processes related to tire pressure detection according to a program stored in the ROM. To do.

  For example, the control unit 33 obtains the tire pressure by performing various signal processing and calculations based on data related to the tire pressure stored in the frame received from the radio wave reception unit 32 as various types of processing related to tire pressure detection. And the electric signal according to the calculated | required tire pressure is output to the indicator 4. FIG. For example, the control unit 33 compares the obtained tire air pressure with a predetermined alarm threshold Th, and when detecting that the tire air pressure has dropped below the predetermined alarm threshold Th, a signal to that effect is displayed on the display 4. Output. The alarm threshold Th here is set as a value that is reduced by a predetermined ratio (for example, 20%) with respect to the current tire pressure detected last time. For example, the control unit 33 stores the tire air pressure immediately before IG OFF in the memory when the receiver 3 is activated by turning on the IG during the previous run. Based on the stored contents, an alarm threshold Th when the IG is turned on next time is set.

  Furthermore, the control part 33 can also obtain | require the tire air pressure of each of the four wheels 5a-5d, and can output the tire air pressure corresponding to each wheel 5a-5d to the indicator 4. In the memory of the control unit 33, ID information of the transmitters 2a to 2d arranged in the wheels 5a to 5d is stored in association with the positions of the wheels 5a to 5d. For this reason, the control unit 33 recognizes which of the wheels 5a to 5d the transmitter 2a to 2d is attached to by checking the ID information stored in the frame, and the tire pressure is Can identify degraded wheels. Based on this, when the tire air pressure drop occurs, the reduced wheel is identified and output to the display 4. Further, even when the tire pressure drop does not occur, the obtained tire pressure may be output to the display unit 4 in correspondence with the wheels 5a to 5d.

  In this way, the tire air pressure of any of the four wheels 5a to 5d has decreased, or the tire air pressure of each of the four wheels 5a to 5d is transmitted to the display 4.

  In addition, when the door lock / unlock signal received by the radio wave receiver 32 is transmitted, the controller 33 transmits the signal to the body ECU 10. If the operation of the remote key 12 is a specific operation, it is determined that the user has instructed the initialization of the alarm threshold Th, and the currently set alarm threshold Th is initialized. For example, the previous tire pressure information stored in the memory of the control unit 33 is deleted, and the newly obtained tire pressure is stored in the memory. Then, using the new tire pressure as a reference, a value obtained by reducing a predetermined ratio (for example, 20%) with respect to the tire pressure is set as the alarm threshold Th after initialization. In this way, the alarm threshold value Th can be initialized.

  As shown in FIG. 1, the display 4 is arranged at a place where the driver can visually recognize, and is configured by an alarm lamp or a display installed in an instrument panel in the vehicle 1, for example. For example, when a signal indicating that the tire air pressure has decreased is sent from the control unit 33 in the receiver 3, the display device 4 notifies the driver of the decrease in tire air pressure by displaying that effect. Alternatively, when the tire pressures of the four wheels 5a to 5d are transmitted from the receiver 3, the tire pressures are displayed in association with the wheels 5a to 5d.

  The body ECU 10 executes various controls related to the vehicle in addition to the door lock / unlock control in the remote key system. In the present embodiment, only the door lock / unlock control will be described. . When the door lock / unlock signal is input from the receiver 3 based on the operation of the remote key 12, the body ECU 10 outputs a command signal corresponding to the signal to the door lock actuator 11. For example, when a door unlock (unlock) instruction is issued from the remote key 12 and a door unlock signal is transmitted from the receiver 3, the body ECU 10 instructs the door lock actuator 11 to unlock the door. Command signal to be output. When a door lock (locking) instruction is issued from the remote key 12 and a door lock signal is transmitted from the receiver 3, the body ECU 10 sends a command signal to the door lock actuator 11 to lock the door. Output.

  The door lock actuator 11 performs door lock / unlock based on a command signal from the body ECU 10, and is configured by, for example, a door lock motor.

  The remote key 12 is a portable device that is carried by the user, and includes various switches for instructing door lock / unlock control that controls locking and unlocking of a door provided in the vehicle. When the user presses the door lock switch provided in the remote key 12, a door lock signal for instructing door lock is transmitted, and when the user presses the door unlock switch, a door unlock signal for instructing door unlock is transmitted.

  As described above, in addition to the tire pressure monitoring system according to the present embodiment, the remote key system is configured. Next, the operation of the tire pressure monitoring system of this embodiment will be described. However, the operation of monitoring the tire air pressure based on normal periodic transmission, that is, detecting the tire air pressure by detecting the tire air pressure and comparing it with the alarm threshold Th is the same as the conventional one. For this reason, only the initialization operation of the alarm threshold Th, which is a feature of this embodiment, will be described here.

  FIG. 2 is a flowchart of an alarm threshold value initialization process processed by the control unit 33 provided in the receiver 3 of the tire pressure monitoring system according to the present embodiment. The processing shown in this figure is executed by the control unit 33 for each predetermined control cycle based on power supply from a vehicle battery (not shown) regardless of whether the IG is on or off.

  As described above, when the door lock switch or door unlock switch of the remote key 12 is pressed by the user, a door lock signal or door unlock signal is transmitted from the remote key 12 accordingly. At this time, when the user operates the door lock switch or the door unlock switch by a specific operation method, a signal corresponding to the operation is output. For example, when a door lock switch and a door unlock switch are pressed simultaneously, a door lock signal and a door unlock signal are output simultaneously.

  On the other hand, the control unit 33 inputs a door lock signal and a door unlock signal through the antenna 31, and basically controls the door lock actuator 11 in accordance with the input signal and performs door lock / unlock control. Is going. In addition to this, the control unit 33 performs a specific operation in which the user instructs initialization of the alarm threshold Th based on the data sent from the remote key 12 in Step 100 in the alarm threshold initialization processing shown in FIG. It is determined whether or not. For example, as described above, it is determined whether the door lock switch and the door unlock switch are pressed simultaneously. If the operation has been performed, the process proceeds to step 110 to initialize the currently set alarm threshold Th.

  That is, as described above, the previous tire pressure information stored in the memory of the control unit 33 is deleted, and the newly obtained tire pressure is stored in the memory. Then, using the new tire pressure as a reference, a value obtained by reducing a predetermined ratio (for example, 20%) with respect to the tire pressure is set as the alarm threshold Th after initialization. In this way, the alarm threshold value Th can be initialized.

  As described above, the alarm threshold value Th in the tire pressure monitoring system can be initialized by operating the remote key 12. This eliminates the need for a separate initialization switch, and eliminates the need for wiring from the initialization switch to the receiver 3 serving as an ECU for monitoring tire air pressure. Therefore, it is possible to reduce the number of parts and to reduce costs.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above embodiment, the receiver 3 is shared so that the receiver 3 in the tire pressure monitoring system can also receive signals sent from the remote key 12 in the remote key system. However, it is not always necessary to share the receiver 3. For example, a remote key ECU for receiving a signal from a remote key may be connected to the body ECU, and the body ECU may be configured to be able to communicate with an ECU for tire pressure monitoring through in-vehicle LAN communication such as CAN communication. . Even in such a form, when the user performs a specific operation of the remote key, the signal transmitted from the remote key is transmitted from the remote key ECU to the body ECU, and is transmitted to the tire pressure monitoring ECU through in-vehicle LAN communication. Can be done. Accordingly, it is not necessary to separately provide an initialization switch, and wiring from the initialization switch to the ECU for monitoring the tire air pressure is also unnecessary, so that it is possible to obtain the same effect as in the above embodiment.

  Moreover, in the said embodiment, the value reduced by the predetermined ratio with respect to the last tire pressure memorize | stored in memory etc. is used as warning threshold value Th. When the alarm threshold value Th is initialized, the previously stored tire pressure is deleted, the newly obtained tire pressure is stored in the memory, and the newly stored tire pressure is used as a reference. An alarm threshold value Th is obtained. This is also an example of how to determine the alarm threshold Th after initialization, and the alarm threshold Th may be initialized by other methods. For example, the alarm threshold Th may be initialized by changing to a predetermined value (default value) stored in advance as the alarm threshold Th for initialization. Furthermore, only an example is given for the calculation method of the alarm threshold Th, and for example, a value obtained by subtracting a constant value from the stored tire air pressure may be used as the alarm threshold Th.

  Note that the steps shown in FIG. 2 correspond to means for executing various processes. That is, the part that executes the process of step 100 corresponds to the determining means, and the part that executes the process of step 110 corresponds to the initializing means.

DESCRIPTION OF SYMBOLS 1 Vehicle 2a-2d Transmitter 3 Receiver 4 Indicator 5a-5d Wheel 6 Car body 12 Remote key 21 Sensing part 22,33 Control part

Claims (3)

A plurality of wheels (5a to 5d) including tires, each of which is provided with a sensing unit (21) for outputting a detection signal related to tire air pressure of each of the plurality of wheels, and a detection signal output by the sensing unit is signaled. A transmitter (2) having a first control unit (22) for processing and creating a frame stored as data relating to the tire pressure, and a radio wave transmission unit (23) for transmitting the frame;
The tire pressure is detected based on the radio wave receiving unit (32) provided on the vehicle body side for receiving the frame, and the tire pressure data stored in the received frame, and the detected tire pressure is alarmed. A receiver (3) having a second control unit (33) that determines that the tire air pressure is reduced if the threshold (Th) is lower;
A switch for instructing door lock / door unlock control, which is a door unlocking / locking control provided in the vehicle, is provided, and a door lock signal or a door unlock signal is transmitted based on the operation of the switch by the user. A portable device (12)
The second controller is
When receiving the door lock signal or the door unlock signal output from the portable device, determination means (S100) for determining whether or not the operation of the switch is a specific operation;
A tire pressure monitoring system comprising: an initialization unit (S110) that initializes the alarm threshold when the switch is operated in a specific manner.   The second control unit calculates the alarm threshold value based on the previous tire pressure stored as the tire pressure, and the initialization means stores the previous tire pressure stored as the tire pressure. And the newly detected tire pressure when the switch operation is a specific operation is newly stored as the tire pressure, so that the alarm threshold is set based on the newly stored tire pressure. The tire pressure monitoring system according to claim 1, wherein the initialization is performed by calculation.   The receiver is configured to share reception from the transmitter and reception from the portable device by also receiving the door lock signal and the door unlock signal output from the portable device. The tire pressure monitoring system according to claim 1 or 2, characterized by the above.

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