JP3388647B2 - Vehicle anti-theft device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-theft device for a vehicle, and more particularly, it verifies a unique code received from the transmitter side and a code stored in the receiver side immediately after the engine is started and these codes are checked. The present invention relates to an anti-theft device for a vehicle, which prevents the vehicle from being stolen by permitting the operation of an engine only when they match.

[0002]

2. Description of the Related Art In recent years, theft of vehicles has become frequent in various countries. Therefore, conventionally, many anti-theft devices have been proposed to prevent the theft,
It is installed in the vehicle. A system similar to such an anti-theft device is disclosed in, for example, Japanese Patent Laid-Open No. 2-279429.
And is operable by a user authorized to send an encoded critical function enable signal to the engine controller, as disclosed in U.S. Pat.
A security system has been proposed that includes a signaling device that prevents unauthorized users from transmitting feature enable signals. This system is, for example, a device that prevents the engine from starting even if a robber enters the vehicle compartment and turns on the ignition switch.

[0003]

However, a conventional example configured as described above, for example, Japanese Patent Laid-Open No. 2-2794.
The device disclosed in Japanese Patent Publication No. 29 can prevent general vehicle theft such as theft due to a duplicated key or theft due to direct connection of an electric system such as a starter motor. However, the following theft is dealt with at all. I can't. That is, the applicant of the present application filed Japanese Patent Application No. 6-2970 dated November 30, 1994.
Filed No.86. In this patent application, the unique first code received from the transmitter side immediately after the engine is started is compared with the code stored in the receiver side, and if the codes match, the second code is controlled by the engine. The second code and the code stored in the engine control section are collated with each other to permit engine operation when these codes match, and when they do not match, engine operation is permitted. There has been proposed a vehicle antitheft device that is stopped. In a vehicle equipped with this kind of anti-theft device, if a legitimate driver starts the engine after starting the engine, the engine continues to operate, while if a robber starts the engine, By checking the code for illegal acts, the engine that has been started is stopped after that. For this reason, in vehicles equipped with this kind of anti-theft device, the engine operation can be continued by performing some special operation to prevent the robber from stopping the engine during the time when the code is collated. It is assumed that the vehicle will be stolen.

Therefore, the present invention has been made in order to solve such a problem, and a unique code received from the transmitter side after starting the engine once and a code stored in the receiver side are provided. An object of the present invention is to provide a vehicle anti-theft device capable of surely preventing a vehicle equipped with the anti-theft device for collation.
It is another object of the present invention to provide a vehicle antitheft device that can effectively utilize a backup RAM provided in an engine control unit. further,
An object of the present invention is to provide a vehicle antitheft device capable of reliably preventing the vehicle theft even in cold weather.

[0005]

In order to achieve the above object, the vehicle antitheft device according to the present invention stores a unique first code received from the transmitter side immediately after the engine is started and stored in the receiver side. The code determining unit that outputs the second code to the engine control unit and the code stored in the engine control unit are compared with each other. And an engine control unit that allows the engine to operate when the codes match, a counting unit that counts the number of times the switch power supply is turned on and off within the matching time of the second code of the engine control unit, A memory holding unit provided in the engine control unit and capable of storing and holding a predetermined period after the battery power is turned off, and the memory holding unit is a switch counted by the counting unit. A memory holding unit that stores the number of times the power source is turned on and off, and the engine control unit that is provided with the engine control unit and forcibly stops the operation of the engine when the switch power supply is turned on and off continuously for a plurality of times And an engine operation stopping means for causing the engine to stop. Further, in the present invention, the storage holding unit may be provided so as to have a backup power supply always connected to the battery power supply side and store the failure code.

Further, in the present invention, the engine operation stopping means is provided so that the predetermined number of times is set to be a larger value when the outside air temperature is less than the predetermined value and above the predetermined value. May be.

[0007]

In the present invention thus constructed, the code judging section collates the unique first code received from the transmitter side with the code stored in the receiver side immediately after the engine is started, and these codes are collated. If the two match
Is output to the engine control unit. Next, the engine control unit collates the second code with the code stored in the engine control unit, and when the two codes match, the engine operation is permitted. Further, the counting means counts the number of times the switch power supply is turned on and off within the collation time of the second code of the engine control unit,
The counted number of times the switch power supply is turned on and off is stored and held in the storage holding unit for a predetermined period. When the battery power is continuously turned on / off and a plurality of predetermined times are counted, the engine operation stopping means forcibly stops the operation of the engine.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a system block diagram of a vehicle antitheft device according to an embodiment of the present invention. As shown in FIG. 1, the vehicle antitheft device according to this embodiment includes a transponder 1, an antenna 2 that receives a signal from the transponder 1, an amplifier 3 that amplifies a signal captured by the antenna 2, and an amplifier. Immobilizer unit 4 controlled by a signal from EGI and EGI for engine control
It is a system including a unit 9. More specifically, the transponder 1 is a key for turning on and off the ignition switch of the automobile on the driver side. Further, the antenna 2 is an ignition coil antenna that operates in conjunction with turning on and off of the ignition switch. In the amplifier 3, when this coil operates and a voltage is applied, the voltage is amplified to a constant value in order to obtain a high voltage. The immobilizer unit 4, which is called an immobilizer unit, is a controller that has recently been developed in Europe to prevent theft and that prohibits engine start by EGI. When the vehicle gets off, the ignition switch automatically turns off. Set.

The immobilizer unit 4 has a battery power source (+
B) 14 and the switch power supply (IG1) 15 are provided with ON / OFF information of the ignition switch, and the transponder 1 is provided with ID data on the basis of the voltage value amplified by the amplifier section 3 to perform a predetermined control. Send a signal to the EGI unit. Further, since the immobilizer unit 4 is connected to the battery power source 14, for example, even if the engine is stopped and the ignition switch is turned off, the power is supplied and the standby state is maintained. In addition, it is connected to an indicator 16 provided in the vehicle compartment, and blinking and extinguishing are controlled by ID data transmitted from the transponder. The EGI unit is a controller that controls the engine speed, the fuel injection amount, and the like. Further, the EGI unit 9 has the EEPROM 1 in which data is stored in advance, like the configuration of the immobilizer unit.
0, the RAM 11 that temporarily stores data in the data transfer with the immobilizer unit 4 described above, the timer 12 that sends the data transfer timing stored in these memories as data, based on the timing information from the timer 12. It is composed of a CPU 13 that controls data exchange with the immobilizer unit 4. In addition, the EGI unit 9 receives a predetermined control signal from the immobilizer unit 4,
The starter, the fuel injection amount, etc. are controlled based on the signal. Further, unlike the case of the immobilizer unit 4, the EGI unit 9 operates as the switch power supply 15 while interlocking with the turning on and off of the ignition switch, so that the power is turned off when the engine is stopped and the ignition switch is turned off, for example. It will be.

Further, the EGI unit 9 has a backup RAM 17. This backup RA
M17 is used for diagnosing a failure by storing a failure code indicating the presence or absence of a past failure of the sensors.
Therefore, the backup RAM 17 is always connected to the battery power source (+ B). Further, the backup RAM 17 is capable of storing and holding for a predetermined period even when the battery power is turned off. Next, with reference to FIG. 2, a data transmission / reception procedure between the transponder 1, the immobilizer unit 4, and the EGI unit 9 will be described. FIG. 2 is a diagram illustrating a procedure for determining ID data of the transponder 1 having certain unique ID data.
In the following description, the transponder 1 transmits an ID code representing a unique code of the key to the immobilizer unit 4, and the immobilizer unit 4 transmits the ID code to the EGI unit 9 as a codeword (hereinafter, abbreviated as CW). Send the password. A codeword is a code registered in the immobilizer unit 4 and the EGI unit 9 one by one, and the same codeword is registered in each unit. <Determination and registration of ID code> In FIG. 2, when the transponder 1 is inserted into the key hole and the ignition switch is rotated to operate the engine, the EGI unit 9 issues a CW request to the immobilizer unit 4 and receives it. The immobilizer unit 4 issues an ID request to the transponder 1 and sends an ID signal from the transponder 1 that serves as a trigger signal for the immobilizer unit 4.
Send to. The immobilizer unit 4 temporarily stores the transmitted ID code of the transponder 1 in the RAM 6 in the unit. After this, the EEPR in the immobilizer unit
The CPU 8 collates the ID code registered in the OM 5 with the ID code transmitted from the transponder 1. The immobilizer unit 4 transmits an engine operation permission signal (immobilizer function cancellation command) and CW to the EGI unit 9 if the ID code comparison results match. If they do not match, an engine operation stop signal (immobilizer function setting command) is transmitted, and the EGI unit 9 receives the signal and stops the engine. The EGI unit 9 stores the CW from the immobilizer unit 4 in the RAM 11, and the CW from the immobilizer unit 4 and the EEPR in the EGI unit 9 are stored.
The CW registered in the OM 10 is collated, and if they match, the engine is continuously operated, and if they do not match, the engine is stopped.

3 to 5 are IDs on the immobilizer unit side.
It is a flowchart which shows the determination procedure of a code. Figure 3,
As shown in FIG. 4, when the processing is started and the ignition switch is rotated to the ON position by the key incorporated in the transponder, the immobilizer function release determination waiting state is entered, and the engine start mode is temporarily permitted. After that, in step S2, it is determined whether the ignition switch is rotated to the starter position by the key incorporated in the transponder and the engine is started. When the engine starts (determination in step S2 is YE
S), the process proceeds to step S4, and when it is determined that the program has not started (NO in step S2), the process returns to the start point of the program. In step S4, it is determined whether or not a predetermined condition (a stable state at an engine speed of 500 rpm and a voltage of 10 V or more) is satisfied. Step S4
If the predetermined condition is satisfied (YES in step S4), the process proceeds to step S6. On the other hand, step S
If the predetermined condition is not satisfied in step 4 (NO in step S4), the process returns to the start point of step S4. In step S6, it is determined whether or not a CW request has been issued from the EGI unit side. When it is determined in step S6 that the CW request is issued (YES in step S6), the process proceeds to step S8. Also, step S
When it is determined that the CW request has not been issued in step 6 (NO in step S6), the process returns to the start point of step S6. Then, in step S8, step S
According to the CW request in 6, the ID request is issued to the transponder. Then, it progresses to step S10. Step S
At 10, I from the transponder that issued the ID request
It is determined whether or not a D response has been received, and if a response has been received (YES in step S10), step S12
If no reply is received (NO in step S10), the process proceeds to step S40 described below.

In step S12, it is determined whether the ID code is registered in the EEPROM incorporated in the immobilizer unit. Immobilizer unit E in step S12
If the ID code is not registered in the EPROM (NO in step S12), the process proceeds to step S30. In step S30, the ID code is temporarily stored in the RAM of the immobilizer unit, and then in step S32, the ID code and CW are EG together with the ID unregistered command (IE command).
Send to I unit. After that, the process proceeds to step S34, and it is determined whether or not there is a response to the transmission of the ID code and CW from the EGI unit. EG in step S34
When there is a response from the I unit to the transmission of the ID code and CW (YES at step S34), the process proceeds to step S36. In step S36, the response from the EGI unit is OK (that is, the transponder ID and EG
If the IDs registered in the I unit are the same), the ID stored in the RAM of the immobilizer unit is registered in the EEPROM, and then the process goes to step S38 to turn off the indicator. In addition, the determination in step S34 described above is N
In the case of O, the process returns to the start point of step S34.
Further, in step S12 described above, the EEP of the immobilizer unit is performed.
If the ID code is registered in the ROM (step S
If the determination is YES in step 12), the process proceeds to step S14 shown in FIG. In step S14, the ID transmitted from the transponder and the ID registered in the immobilizer unit
And match. Then, in step S16, it is determined whether or not these IDs match, and if they match (YES in step S16), the process proceeds to step S18.
If they do not match (NO in step S16), the process proceeds to step S20. In step S18, the immobilizer function cancel command and CW are transmitted to the EGI unit, and this program ends.

Further, the judgment in step S16 is N.
When it becomes O and the process proceeds to step S20, step S2
At 0, the immobilizer function setting command is transmitted to the EGI unit, and then at step S22, the processes at steps S6 to S14 are repeated again. Then, in step S24, it is again determined whether or not the ID transmitted from the transponder and the ID registered in the immobilizer unit match. As a result, if they match (YES in step S24), the process proceeds to step S18, and if they do not match (step S24).
If the determination is NO), the process proceeds to step S26, the immobilizer function setting command is transmitted to the EGI unit again, and the process returns to step S2 in FIG. Since the immobilizer function is automatically set by turning off the ignition switch, if the immobilizer function is not canceled, the immobilizer function is set or the immobilizer function cancellation determination waiting state described above is entered. That is, the immobilizer function setting command in step S26 and step S52, which will be described later, is exactly the immobilizer function setting maintenance command. <ID judgment procedure on the immobilizer unit side when the ID code cannot be transmitted> Next, the ID code judgment procedure when the ID code cannot be transmitted to the immobilizer unit due to a transponder failure will be described. In this way, the transponder 1 fails and I
If the D code cannot be transmitted, first, on the immobilizer unit 4 side, the operator (driver) is made to blink a warning lamp or the like that the ID signal from the transponder 1 cannot be received or the ID signal cannot be read. To warn. Upon receiving this warning, the operator (driver) recognizes the abnormality of the transponder 1. Further, the unreceivable or the ID signal cannot be read means that the code is not transmitted or the signal waveform representing the transmitted ID code is dull.

FIG. 5 is a flow chart showing the ID code determination procedure on the immobilizer side when transmission is impossible.
In step S10 shown in FIG. 3, when the ID response from the transponder is not received (step S10)
If the determination is NO, the process proceeds to step S40 shown in FIG. In step S40, it is determined that the ID code cannot be transmitted,
The warning lamp blinks to notify the driver of an abnormality such as a transponder failure or a break in the communication line (between the antenna and the immobilizer unit). Then, step S4
Then, the process proceeds to step 2, and it is determined whether or not there is a CW input by the driver's predetermined operation with the ignition switch. In step S42, if there is a CW input by the driver's operation of turning on / off the ignition switch (YES in step S42), the process proceeds to step S44, and the CW registered in the EEPROM in the immobilizer unit and the above-mentioned predetermined value. The CW input by the operation is compared. Then, in step S46, it is determined whether the CWs match,
When it is determined that they match with each other (the determination in step S46 is Y).
ES), the process proceeds to step S48, and the immobilizer function release command and CW are transmitted to the EGI unit. On the other hand, if it is determined in step S46 that the CWs do not match (NO in step S46), the process proceeds to step S52, the immobilizer function setting command is transmitted to the EGI unit, and then the process returns to step S2 in FIG. When it is determined in step S42 that there is no CW input by the predetermined operation (NO in step S42), the process proceeds to step S52, and an immobilizer function setting command is transmitted to the EGI unit.

After transmitting the immobilizer function cancel command and CW in step S48 described above, in step S50,
Turn off the warning lamp. <CW Judgment Procedure on EGI Unit> Next, the CW judgment procedure on the EGI unit side will be described. 6 and 7 show
7 is a flowchart showing a CW determination procedure on the EGI unit side. In FIG. 6 and FIG. 7, when the process is started, in step S60, the timer counts 500 milliseconds after the ignition is turned on while waiting for the immobilizer function release determination and the number of CW requests to the immobilizer unit being zero. Start. In step S62, it is determined whether an additional write command has been received. Next, step S
In step S64, it is determined whether the engine speed is 500 rpm or more and the voltage is 10 V or more as a predetermined condition. If the predetermined condition is satisfied in step S64 (determination in step S64 is YES), the process proceeds to step S66. If the predetermined condition is not satisfied (determination in step S64 is NO), the process returns to the start point of step S64. In step S66, step S60
It is determined whether or not the counting of 500 milliseconds started at is finished. When the counting of 500 milliseconds is completed in step S66 (YES in the determination in step S66), the process proceeds to step S68, and when the counting of 500 milliseconds is not completed in step S66 (the determination in step S66 is N).
O), and returns to the start point of step S66. In step S68, the EGI unit issues a CW request to the immobilizer unit. Then, the process proceeds to step S70, and it is determined whether or not there is a response from the immobilizer unit to the EGI unit to release the immobilizer function and CW. Step S7
0 to immobilize function release command and CW from immobilizer unit
If it is determined that there is a response (YES in step S70), the process proceeds to step S72, in which the RA on the EGI side is RA.
The CW is temporarily stored in M11. Then, it progresses to step S78 which shows the continuation in FIG. In step S78, it is determined whether or not the CW is registered in the EEPROM incorporated in the EGI unit. In step S78,
If the CW has already been registered in the EEPROM of the EGI unit (YES in step S78), step S82
And the CW stored in the RAM is E of the EGI unit.
It is determined whether or not it matches the CW registered in the EPROM. The CW stored in the RAM in step S82 is E
When it is determined that it matches the CW registered in the EEPROM of the GI unit (the determination in step S82 is Y
ES), the process proceeds to step S84, the immobilizer function is canceled, and normal EGI control is executed. In step S82, the CW stored in the RAM is the EGI unit E
If it does not match the CW registered in the EPROM (NO in step S82), the process returns to step S74.

Further, in the above-mentioned step S70, when it is determined that the immobilizer release command and the CW are not returned from the immobilizer unit (NO in step S70),
It proceeds to step S74. In step S74, it is determined whether or not the CW request has already been made 5 times to the immobilizer unit. If it is determined in step S74 that the CW request has been made 5 times (YES in step S74), the process proceeds to step S76, it is determined that the device is malfunctioning or stolen, the immobilizer function is set, and the engine is stopped. . On the other hand, if it is determined in step S74 that the process has not been performed five times (NO in step S74), the process returns to step S68, and the CW request is again issued to the immobilizer unit. FIG. 8 is a timing chart showing each operation of the transponder, the ignition switch, the immobilizer unit, and the EGI unit in the above-described ID code determination procedure. <Theft Prevention Judgment Procedure by Switch Power Operation by EGI Unit> Next, the antitheft judgment procedure by the switch power operation by the EGI unit will be described with reference to FIGS. 8 and 9. As described above, in the vehicle equipped with the anti-theft device according to the present embodiment, when the regular driver starts the engine after the engine is started, the engine continues to operate, while the robbery starts the engine. In such a case, the code is checked for the fraudulent activity, and the engine once started is stopped after the verification. For this reason, a robber may momentarily turn on / off the switch power supply by some operation, that is, switch off the switch power supply within a time period during which the code is collated immediately after the engine is started (the item of the switch power supply IG1 in FIG. 8). It is assumed that the vehicle is stealed by using the inertial force of the engine to continuously rotate the engine to prevent the immobilizing function from being set, and the setting of the immobilizing function is prevented. The same applies to the battery power supply, and the same procedure as the switch power supply in the following description is applied.

In the present embodiment, the theft due to such switch power source operation is prevented by the determination procedure shown in FIG. Specifically, after the key is turned on in step S102, the process proceeds to step S104,
Determine if the engine is running. If the engine is not operating, the process returns to the start point of step S104, and if the engine is operating, the process proceeds to step S106. In step S106, it is determined whether the engine is in a warm state or a cold state by determining whether the outside air temperature is equal to or higher than the predetermined temperature T ₀ . If the engine is in the warm state, the process proceeds to steps S108 and S110, and if it is in the cold state, the steps S112 and S1.
Proceed to 14. Then "cbak" in these steps
"small", "cbaklarge" and "cba"
The contents of "k" will be described. That is, "cbaksmall"
Is a value for counting the number of times when the switch power supply in the warm state is turned on and off within the code matching time, and "cbaklarge" is the switch power supply in the cold state is turned on and off within the code matching time. This is a value value for counting the number of times when it is done. "Cbak"
The final "cbaksmall" and "cbakla"
It is a value replaced with the count value of “rge”. These "cbaksmall" and "cbaklarg"
The initial value of “e” is preset as the initial values α and β for confirming the fraudulent activity by the robbery in step S128, which will be described later, and is stored and retained in the backup RAM 17.

The number of times this switch power supply is turned on and off is
The switch power is turned on within the above code verification time.
When it is turned off, it is counted once. The count value obtained by turning on / off the switch power supply is stored and held by the backup RAM 17, but even when the battery power supply is turned off, the count value can be stored and held for a predetermined period. This predetermined period is a time long enough to cover a predetermined number of times of turning on / off of the switch power source, which will be described later. Specifically, as shown in FIG. 8, first, at the time “t ₀ ”, if there is a key-on operation, which is the original operation, the switch power supply changes from off to on, so “cbaksmall”. Or "c
"baklarge" is counted once. afterwards,
If the switch power supply is momentarily turned on and off within "M ₀ ", which is the original code matching time, the matching time becomes "M ₁ ", and either "cbaksmall" or "c".
"baklarge" is counted once,
At time “t ₁ ”, the next code collation is started by the collation start reset. After that, when the switch power supply is momentarily turned on and off again, the matching time becomes “M ₂ ”, which is “cbaksmall” or “cba”.
“Klage” is counted once, and at the time “t ₂ ”, the next code collation is started by the collation start reset. Further, when the switch power supply is momentarily turned on / off again, the matching time becomes “M ₃ ”, which is “cbaksmall” or “cbaklarg”.
with e "is 1 batch count, the following code collation is started by matching initiated reset at time" t ₃ ". In this way, the case where the switch power supply is momentarily changed on / off / on is counted.

Thus, in the warm state, the
In step S108, the code matching time (M₁, M₂, M₃
・ ・ ・ ・) Switch power supply was turned on / off momentarily
In some cases (including key-on operation, which is the original operation),
Each time, "cbaksmall" is set to the initial value α.
Decrease by "1" from the existing "cbaksmall"
The value "cbaksmall-1" is replaced.
Then, in step S110, "cbak"
Replaced with the final "cbaksmall" value
It Similarly, in the cold state, step S11
2, the code matching time (M ₁, M₂, M₃・ ・ ・ ・)
If the switch power is turned on / off momentarily (the original
(Including the key-on operation which is an operation), "cb
“Akrage” is set to the initial value β “c
The value "cb" that is subtracted by "1" from "baklarge"
akrage-1 ". After that,
In step S114, "cbak" is the final "c
It is replaced with the value of "baklarge". Mentioned above
The first of "cbaksmall" and "cbaklarge"
The period values α and β are positive integers, and β> α
There is. In this way, the engine cold state is warmer
It is set to a larger value than when. The reason for this is
It is as below. That is, the key is inserted and the ignition
Enclosed in the key hole when the power switch is turned on and off
The key is inherently ignited by the influence of grease.
Even if the switch is operated to the on position,
It may be turned off due to the influence of the battery. This trend is
It is larger in the cold state where the lease is more viscous. But
The viscosity of the grease inside the keyhole.
By considering, "cbaksmall" and "cb
Set α and β, which are the initial values of “akrage”, and
As a result, the initial value of “cbak” indicates that the engine is cold.
It should be set to a higher value than in the warm state
It Thus "cbaksmall" and "cbak
By setting the initial value of "large"
In the cold state, poor contact may occur due to the effect of grease.
As a result, the switch power may be turned on or off by mistake.
However, it is not affected by the malfunction.

In this way, after the value of "cbak" is set in step S110 and step S114, the process proceeds to step 116. In step S116, it is determined whether "cbak" is smaller than zero.
If "cbak" is less than zero, it means that the switch power supply has been turned on / off a predetermined number of times, which is set as the initial value, within the code matching time, and that the robber is performing such an operation. Conceivable. Therefore, if YES is determined in step S116, the process proceeds to step S118, and the operation of the engine is stopped by setting the immobilizing function. On the other hand, step S1
If NO is determined in step 16, step S
Proceed to 120, transponder 1, immobilizer unit 4
Then, it is determined whether or not the communication conditions between the EGI unit 9 and the EGI unit 9 are satisfied. The establishment of this communication condition is a well-known general one, and is determined by whether or not the communication line is busy. If the communication condition is not satisfied, the process returns to the starting point of step S120, while if the communication condition is satisfied, the process proceeds to step S122 to start communication. Next, in step S124, it is confirmed whether or not the key is the correct key. This step S124
The procedure of the key confirmation in is substantially the same as the contents of steps S60 to S84 in FIGS. Therefore, the description thereof is omitted here.

After that, if the key cannot be confirmed, the process proceeds to step S118, and the operation of the engine is stopped by setting the immobilizing function. If it is confirmed that the key is correct, the process proceeds to step S126,
Immobilization function is canceled. Then, as described above, in step S128, in preparation for the next engine starting operation, "cbaksmall" and "cbaklarg" are prepared.
The initial values α and β are set in advance in “e”, and the routine ends. After that, the original engine control (for example, control of the fuel injection amount) is executed. In the vehicle antitheft device of the present embodiment configured as described above,
Even if the robbery tries to steal the vehicle by continuing the operation of the engine once started by repeating the verification start by turning the switch power supply on and off momentarily and turning it off momentarily within the code matching time. The operation of the engine is forcibly stopped by detecting and storing such operation in the backup RAM. As a result, it is possible to reliably prevent the vehicle from being stolen by such an action that the switch power supply is momentarily turned on / off and momentarily disconnected. In addition, in this embodiment,
Since the backup RAM 17 in the EGI unit 9 is used to store and hold the action of turning the switch power supply on and off momentarily and turning it off instantaneously, the backup R
AM can be effectively utilized. Further, even if the battery power is turned off, the backup RAM 17 can store and hold the data for a predetermined period, so that such a robbery operation can be reliably prevented.

Further, in this embodiment, even when the grease in the keyhole causes a contact failure due to high viscosity in the cold engine state, the switch power supply is momentarily turned on / off to be momentarily disconnected. It is possible to reliably prevent the vehicle from being stolen due to such an act.

[0023]

As described above, according to the vehicle antitheft device of the present invention, the unique code received from the transmitter side and the code stored in the receiver side are collated immediately after the engine is started. It is possible to surely prevent the vehicle equipped with the anti-theft device described above from being stolen. Further, according to the present invention,
The backup RAM provided in the engine control unit can be effectively used. There is. Furthermore, according to the present invention, it is possible to reliably prevent the vehicle from being stolen even during cold weather.

[Brief description of drawings]

FIG. 1 is a system block diagram showing an embodiment of a vehicle antitheft device according to the present invention.

FIG. 2 is a block diagram illustrating a procedure for determining an ID code and a codeword of a transponder having certain unique ID data.

FIG. 3 is a flowchart showing a procedure for determining an ID code on the immobilizer unit side.

FIG. 4 is a flowchart showing a procedure for determining an ID code on the immobilizer unit side.

FIG. 5 is a flowchart showing the ID code determination procedure on the immobilizer unit side when the ID code cannot be transmitted.

FIG. 6 is a flowchart showing an ID code determination procedure on the EGI unit side.

FIG. 7 is a flowchart showing an ID code determination procedure on the EGI unit side.

FIG. 8 is a timing chart showing each operation of the transponder, the ignition switch, the immobilizer unit, and the EGI unit in the determination procedure of the ID code and the EW code.

FIG. 9 is a flowchart showing a theft determination procedure by operating a switch power supply by an EGI unit.

[Explanation of symbols]

1 transponder 2 ignition coil antenna 3 amplifier 4 Imobi Unit 5 Immobilizer unit side EEPROM 6 Imobi side RAM 7 Immobilizer side timer 8 Imobi CPU 9 EGI unit 10 EGI unit side EEPROM 11 EGI unit side RAM 12 EGI unit side timer 13 EGI unit side CPU 14 Immobilizer side and backup RAM power supply 15 EGI unit side power supply 16 indicators 17 Backup RAM

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-164648 (JP, A) JP-A-2-164647 (JP, A) JP-A-8-156746 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B60R 25/04

Claims (3)

(57) [Claims] 1. Immediately after starting the engine, a unique first code received from the transmitter side is compared with a code stored in the receiver side, and when the codes match, the second code is given to the engine control section. A code determination unit that outputs the second code, the engine control unit that allows the engine to operate when the second code and the code stored in the engine control unit are matched, and the codes match, and the engine control unit A counting means for counting the number of times the switch power supply is turned on and off within the second code collation time, and a storage holding portion provided in the engine control portion and capable of storing and holding a predetermined period after the battery power is turned off, The memory holding unit is provided in the engine control unit and a memory holding unit that stores the number of times the switch power source is turned on and off counted by the counting unit. Re antitheft apparatus for a vehicle and having a an engine operation stop means for stopping the operation of the forced engine when the on-off of the switch power is more a predetermined number of times continuously counted. 2. The anti-theft device for a vehicle according to claim 1, wherein the storage holding unit has a backup power supply which is always connected to a battery power supply side and stores a failure code. 3. The engine operation stopping means sets the predetermined number of times such that when the outside air temperature is less than a predetermined value, it becomes larger than when the outside air temperature is more than the predetermined value. The vehicle antitheft device according to 1.