JPH06137009A - Radio wave key device of car provided with voltage drop monitoring function - Google Patents

Abstract

PURPOSE:To increase reliability of a voltage drop monitor system, by converting a battery voltage into radio wave and transmit it repeatedly every time when switching on the transmitter and analyzing the received codes at the receiver side to comparing it with a previously decided base figures and indicating the consumed degree of the battery. CONSTITUTION:When the switch 6 of a radio wave key 1 for a car is turned on, the voltage of battery 7 is measured at each given interval by a voltage monitor 2 and a code format is output in a code generator 3. The code is converted to radio wave signals 8 and transmitted repeatedly in specified times. On the other hand, signal codes are analyzed in CPU 12 in accordance with the signals received in a receiver 9 and judging signals of the consumed degree of battery are output. The consumed degree of battery 7 is shown on the indicator 13 in the car. In this way, the reliability of the consumed degree monitor of the battery 7 can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle electric wave key device for locking and unlocking a vehicle door by radio waves, and more particularly to a vehicle electric wave key having a battery voltage drop monitoring function for operating a transmitter. Device related

2. Description of the Related Art In a vehicle such as an automobile, a door is locked with a key in order to prevent unauthorized use or theft by persons other than the owner's vehicle. However, an automobile may be stolen by an unauthorized unlocking operation such as using a picking key or a duplicate key to unlock the lock without damaging it, or removing the key sealing inner or the key reeling outer. In order to prevent such a car theft, a key device using magnetism or radio waves has been proposed.

[0002]

Since the radio wave key device does not use a lock and a key as in the prior art, it has an effect of preventing an illegal unlocking due to an illegal act such as a duplicate key being made or picking. However, since the radio key device uses a battery for the power supply of the transmitter, there is a problem that the battery does not operate when the battery is exhausted. The deterioration of the battery is not known until the device stops operating, and when the device stops operating, it is not known whether the cause is battery deterioration or a device failure.

For this reason, it has been practiced to provide a monitoring circuit for monitoring the degree of exhaustion of the battery, and to attach a device which issues an alarm when the battery is used up to a certain limit. However, the voltage drop of the battery changes with one operation time, and the reference voltage of the monitoring circuit also has a tolerance, so an alarm may be issued even when the battery has a large usable capacity.
There was a problem that the reliability of the alarm was low. An object of the present invention is to provide a radio wave key device for a vehicle, which can improve the reliability of monitoring the exhaustion degree of a battery provided in a transmitter.

[0004]

In order to achieve the above object, a radio wave key device for a vehicle having a voltage drop monitoring function according to the present invention measures a battery and the voltage of the battery, and measures the measured voltage. When the battery voltage exceeds the reference value, the first
A voltage monitoring device that outputs a second signal of battery voltage drop when the measured voltage is less than or equal to a reference value, a code generation unit that encodes the signal and the vehicle unique number, A transmission unit that converts the code generated by the code generation unit into a radio signal and repeatedly outputs the radio signal by a predetermined number of times by one transmission operation, and a transmission antenna that transmits the radio signal from the transmission unit to the air. A transmitter provided, a receiving antenna for receiving the radio signal, a signal for repeatedly processing the first or second signal code and the vehicle's unique number code from the repeatedly received radio signal, and a first signal code for the first signal code. A battery exhaustion determination signal is output based on a detection value corresponding to the first signal code before being changed to the second signal code, and an operation signal of a vehicle door drive unit is output based on a vehicle unique number. Control A receiver and a part, the consumption degree determination signal of the battery outputted from the control unit, in the configuration provided with a display means for displaying the degree of wear of the battery.

[0005]

According to the electric wave key device for a vehicle having the above structure, the first signal when the measured battery voltage output from the voltage monitoring device exceeds the reference value, or the measured battery voltage is below the reference value. Then, the second signal together with the unique number of the vehicle is generated in the code generation section in the code generation section, the code is converted into a radio wave by the transmission section, and is repeatedly transmitted. When the receiver receives the radio waves repeatedly sent, and the detected value of the first signal before changing from the first signal to the second signal exceeds a predetermined battery consumption determination reference value, It is judged that the remaining life of the battery is sufficient, and it is displayed on the display means. When the detected value becomes less than or equal to the battery exhaustion determination reference value, it is determined that the battery is exhausted, and the display means displays it. By repeating the measurement in this manner, the reliability of the battery voltage monitoring can be improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a radio wave key device for a vehicle of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, a transmitter 1 is composed of a voltage monitoring device 2, a code generator 3, a transmitter 4 and a transmitting antenna 5, and is connected to a battery 7 for operating the transmitter 1 via an operation switch 6. There is. The voltage monitoring device 2 measures the voltage of the battery 7 at regular intervals and outputs it as a 1-bit voltage pulse. The code generator 3 has a function of coding the voltage pulse and adding it to the code of the unique number (ID) of the vehicle to generate a predetermined code format. The transmitting unit 4 and the transmitting antenna 5 operate in the same manner as in the conventional case, and transmit the code format signal 8 to the air.
In addition, the voltage monitoring device may be composed of a discrete,
It is also possible to configure it with a custom IC including a code generator and the like.

On the other hand, the receiver 9 comprises a receiving antenna 10, a receiving section 11 and a CPU 12 as a control section, and a display 13 as a display means and a door drive section 14 are connected to the CPU 12. The receiving unit 11 receives the radio wave signal 8 via the receiving antenna 10, and the CPU 12 analyzes the signal code of the battery voltage from the radio wave signal 8 and displays it on the display 13 according to the consumption level of the battery 7. , Causes the door drive unit 14 to perform a predetermined operation. FIG. 2 shows an example of the code format generated by the code generator 3.
The code format corresponds to the activation code 21, the vehicle ID, for example, 24-bit ID bit 22, 1-bit battery voltage bit 23, parity 24, end pit 2.
5 and.

Next, the operation of this embodiment will be described with reference to FIGS. 3 and 4. In FIG. 3, when the switch 6 of the transmitter 1 is turned on and started, the circuits of the respective parts are energized and brought into an operating state. First, the voltage monitoring bit input process (S10
In 0), the voltage monitoring device 2 measures the voltage of the battery 7 at regular time intervals, compares the sequentially measured voltage value with a predetermined reference voltage value, and based on the result, determines the 1-bit battery voltage bit 23. It is sent to the code generator 3. Here, the battery voltage bit 23 is set to "1" when the measured voltage value is larger than the reference voltage value, and is set to "0" when the measured voltage value is smaller than the reference voltage value.

The code generator 3 reads the ID code from the ROM and outputs the ID bit 22 corresponding to the ID code.
The code format shown in FIG. 2 is generated from the battery voltage bit 23 from the voltage monitoring device. Next, in the code output process (S101), the transmitter 4 converts the generated code format into the radio signal 8 and outputs the radio signal to the air. Then, the next measured voltage value is similarly processed.
This is transmitted once, that is, each time the battery power is turned on, the measurement is performed a predetermined number of times, and the code output process is performed based on each measured voltage value.

On the other hand, when the receiver 9 starts reception, a processing routine for driving the door and monitoring the battery voltage and a signal input processing routine are activated. First, the voltage bit counter that counts the number of voltage bits is cleared (S200).
The signal input process is started and sent from the receiving unit.
Is processed (S300), and the number of codes until the voltage bit is inverted is counted by the voltage bit counter (S301). In the example of FIG. 5, (a) is 6, (b)
Is 5 and (c) is 2 is a count value.

When the signal input processing is started, the receiving section 11
It is determined whether a signal is input to the CPU 12 (S201), and if there is a signal input, the ID information and the counter information of the voltage bit are input to the CPU 12 from the processed signal code. CPU
In 12, the ID code is collated with the vehicle code registered in advance, and it is compared whether or not they match (S202). If they do not match, the process returns to the next signal input determination process (S201) without performing the subsequent process. If they match, the operation process of the door drive unit is executed (S203). Then, the counter value of the voltage bit counter repeatedly sent is compared with the threshold value (S204).

As for the threshold value, for example, the counter value is "10".
When the counter value is "5" and when the counter value is "5", the value "2" is set in advance, and when the counter value becomes equal to or less than the threshold value, it is determined that the voltage has dropped. That is, when the counter value exceeds the threshold value, it is determined that there is a battery voltage, and the process returns to the process (S201) by the next transmission operation. If the counter value is less than or equal to the threshold value, it is determined that there is no battery voltage, and the display unit 13 displays that the battery voltage is low (S205). When the signal code is continuously received, the door drive unit operates immediately if the first signal code determines that the ID is correct, but the subsequent command operates to prevent chattering of the door drive unit by a radio wave. Ignore until the signal goes off.

An example of the determination of the battery voltage drop will be described with reference to FIG.
If come repeatedly transmitted times, the inverted voltage signal code e _s battery as shown in FIG. 5 (a) is detected in the sixth,
Alternatively, if it is detected at the fifth time as shown in (b), it is judged that the remaining voltage of the battery 7 is sufficient, and if it is reversed at the second time as shown in (c), it is judged that the voltage has dropped. It The reference number of times for this determination is determined by the voltage drop characteristics of the battery used, the tolerance of the voltage monitoring circuit, and the like.

As the display means, there is a method of displaying the light on an indicator in the vehicle compartment or issuing an alarm with a buzzer or the like. Alternatively, there is also a method in which the operation of the door drive unit is changed to a double action, the door is unlocked, the door is immediately locked, and further, the sound is emitted to notify the user. Also, the door lock operation response time may be delayed. In this embodiment, the remaining battery level is determined by comparing the counter value with the threshold value. However, the counter value for each outgoing operation is stored, and the battery is calculated from the change amount of the previous counter value and the current counter value. The remaining amount may be determined. Further, the remaining battery level may be determined by the time until the signal code is inverted from "1" to "0". In this embodiment, the battery voltage bit counting process is performed after the door driving unit is operated when the ID codes match. However, this counting process is performed in parallel during the operation of the door driving unit. You can also

In this embodiment, the deterioration time is judged by reading the time when the voltage bit is inverted by the reference voltage, but the time when the voltage is inverted changes depending on the temperature condition. Therefore, in order to further accurately determine the inversion time of the voltage bit, two reference voltages having the same temperature coefficient are used and the voltage signal code is given in 2 bits, and the voltage bit is inverted by the first reference voltage. By measuring the time from this time until the voltage bit is inverted by the second reference voltage, the change in the reference voltage due to the temperature condition can be ignored.

[0016]

As described below, according to the present invention,
A code format signal including an ID code and a battery voltage signal code is repeatedly transmitted by one transmission operation,
Since the voltage drop of the battery is monitored by the number of transmissions and the time until the signal code changes, the reliability of the battery consumption level monitoring can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a radio wave key device for a vehicle of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an example of a code format according to the present embodiment.

FIG. 3 is a flowchart illustrating the operation of the transmitter according to the present exemplary embodiment.

FIG. 4 is a flowchart illustrating the operation of the receiver of this embodiment.

FIG. 5 is an explanatory diagram showing an inversion state of voltage bits in the code format according to the present embodiment.

[Explanation of symbols]

1 transmitter, 2 voltage monitoring device, 3 code generator, 4
Transmitter, 5 transmitting antennas, 7 batteries, 9 receivers,
10 receiving antenna, 12 CPU (control unit), 13
Display (display means), 14 Door drive unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahisa Noda 1 Noda, Toyoda, Oguchi-cho, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd.

Claims (1)

[Claims] 1. A battery, a voltage of the battery is measured, and when the measured voltage exceeds a reference value, a first signal with a battery voltage is provided, and when the measured voltage is less than or equal to the reference value. Sometimes a voltage monitoring device that outputs a second battery voltage drop signal, a code generator that encodes the signal and the vehicle's unique number, and a code generated by the code generator is converted into a radio signal. A transmitter including a transmitter that repeatedly outputs the radio signal a predetermined number of times by one transmission operation, and a transmitter antenna that transmits the radio signal from the transmitter to the air, and a receiver antenna that receives the radio signal And processing the first or second signal code and the vehicle's unique number code from the repeatedly received radio signal, and changing the first signal code to the second signal code before changing the first signal code to the second signal code. Corresponding to signal code A receiver having a control unit that outputs the battery exhaustion determination signal based on the output value and an operation signal of the vehicle door drive unit based on the vehicle unique number; and a receiver that outputs the battery output from the control unit. A radio wave key device for a vehicle having a voltage drop monitoring function, comprising: a display unit for displaying the consumption level of the battery according to a consumption level determination signal.