JP2947458B2 - 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 a vehicle anti-theft device, and more particularly to a vehicle which is capable of responding to the addition of an anti-theft function to an engine control circuit for vehicle control with only a minimum change in a control circuit pattern. The present invention relates to an anti-theft device.

[0002]

2. Description of the Related Art Among various proposals made to prevent theft of vehicles such as automobiles, when an attempt is made to start or run a vehicle using an unauthorized key, mechanical and electrical means are used. Prohibition of starting or running the vehicle (immobilize)
There are things that I try to do. For this purpose, an identification code, that is, a key ID code is built in the key, and when the vehicle is started by inserting the key into the key cylinder,
The key ID code is read and the reference I stored in the vehicle in advance is used.
The D code is collated, a permission signal is generated only when the two codes match, and the engine can be started only when the engine control device properly receives it. In this case, if the permission signal is a binary signal of on / off, there is a risk that the theft may be performed due to mechanical destruction or improper wiring, so that it is proposed to code the permission signal. (See, for example, "Automotive Technology," Vol. 48, No. 8, 1994, pp. 59-64).

FIG. 6 shows an example of such a conventional transponder type immobilizer. Key-2
Includes a memory (not shown) in which a key ID code (for example, 64 bits) is stored in advance, and a transmitter 4 for transmitting the key ID code. The transmitter 4 of the key-2 and the key cylinder 6 are connected by, for example, an induction coil (antenna) 6. When the key-2 is inserted into the key cylinder and turned to the ignition position, the ignition switch 7 is closed. In response, the immobilizer CPU 13 operates, and power is supplied from the power amplifier 11 of the immobilizer ECU 10 to the transmitter 4 via the coil (antenna) 6. The transmitter 4 responds to this,
The key ID code is read and transmitted to the key cylinder 6 side.

[0004] The received key ID code is detected and digitized by an R / F (high frequency) circuit 12 in the immobilizer 10, read into a CPU 13, and read by an appropriate I / O circuit.
It is temporarily stored in the D code register 13B. CPU 13
In the EEPROM 13A, a unique reference ID code assigned to each vehicle is stored in advance.
The D code and the read key ID code are compared and collated by the collation function unit 13S of the CPU 13. If it is determined that they match or have a predetermined relationship, a permission code is transmitted from the collation function unit 13S to the engine control circuit 16. At the same time, the starter relay is energized and the starter motor (not shown) starts rotating.

When the engine control circuit 16 determines and confirms the reception of the permission code, the engine control circuit 16 controls the fuel injection valve 17, the fuel pump 18, the ignition control unit 20 and the like according to a predetermined procedure and timing. Then, the vehicle can be started and run. On the other hand, if the reference ID code stored in the EEPROM 13A does not match the key ID code transmitted and read from the key-2, or if the key ID code does not have a predetermined relationship, the matching function unit 13S Is the permission code
Do not send the password. Therefore, the starting of the vehicle by the engine control circuit 16 is prohibited, and the alarm 13 is activated by the CPU 13 to provide an appropriate alarm and display.
In this manner, unauthorized starting and running of the engine due to unauthorized keys are prevented, and vehicle theft is reliably prevented.

Further, as disclosed in Japanese Patent Application Laid-Open No. 62-88644, for example, a bar code stored in an ignition key is compared with a code stored in advance in a vehicle body side anti-theft circuit. It is proposed to generate a start (start permit) signal when both match to enable the engine control ECU, but not to generate a start signal or generate a start prohibition signal when they do not match. I have.

[0007]

In the above-mentioned prior art, the engine is permitted to be started only when the ID signal obtained from the ignition key or the like is determined to be valid. Since the start of the engine is prohibited, the start (start permit) signal is issued due to a failure of the anti-theft circuit itself (breakage of the circuit wiring, short circuit, etc.) even though the start operation is performed by a proper ignition key. There is a problem that the engine cannot be started and the vehicle cannot be run because it is not generated.

[0008] An object of the present invention is to provide a method for detecting a stop of a vehicle anti-theft function due to a malfunction of the anti-theft circuit or the anti-theft detection unit itself, even if there is no confirmation signal from the anti-theft detection unit. It is an object of the present invention to provide a vehicle anti-theft device capable of starting and running a vehicle.

[0009]

SUMMARY OF THE INVENTION A vehicle anti-theft device determines whether a signal supplied to its input is an ID signal indicating a valid start operation, and if the signal is a valid ID signal, determines whether the signal is a valid start operation. A confirmation signal, a theft detection unit for respectively generating a theft signal when the ID signal is not valid, a start permission signal generating means for generating a start permission signal in response to the confirmation signal, and a response to the start permission signal. And an engine control unit for executing control for operating the engine normally. When neither the confirmation signal nor the theft signal is generated from the theft detection unit, the start permission signal generation unit determines that the theft detection unit is not operating normally and generates a start permission signal. The confirmation signal may be a pulse having a predetermined period and a duty ratio, and the theft signal may be a reference (ground) level or a high level DC signal. The confirmation signal, the theft signal, and the signal at the time of failure are connected to the input port of the engine control unit by one signal line from the end of the theft detection unit.

[0010]

When the theft detection unit determines that the signal supplied to the input is an ID signal indicating a valid start operation, it generates a confirmation signal to generate a start permission signal, and the engine control unit starts the engine. On the other hand, if it is determined that the ID signal is not a valid ID signal, a theft signal is generated to disable the engine control unit from starting the engine. When the operation of the theft detection unit itself becomes abnormal, the input level from the theft detection unit to the engine control unit is fixed to a predetermined value, so that the engine can be started and run.

[0011]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a functional block diagram showing a main part configuration of an engine control circuit shown in FIG. In these figures, the same reference numerals as those in FIG. 6 represent the same or equivalent parts.

The permission code described above with reference to FIG.
From the input terminal 24 of the theft detection unit 22
After the noise is removed, the data is further transferred to the code discriminating circuit 28. Then, if it is recognized that the permission code is valid, for example, by comparison with a reference code stored in advance in the code discrimination circuit 28, the code discrimination circuit 28 A confirmation (pulse) signal of a predetermined known frequency and a duty ratio is supplied to an input port Pm of the engine control circuit 16. In this example,
The confirmation signal is a pulse having a duty ratio of 0.5, and the output is a low (ground or reference) level DC signal when no valid permission code is input. Also, since the input port Pm is pulled up to the operating voltage Vcc by the resistor 27, the theft detection unit 22 fails (wiring of the wiring,
The output becomes a high-level DC signal when an abnormality occurs due to a short circuit or the like. It is well known that the various signals described above can be easily formed by a microprocessor or the like.

As can be seen from FIG. 2, the engine control circuit 16 includes start permission signal generating means (16A to 16H) and an engine control unit 16K. It is determined whether or not the signal received at the port is a predetermined confirmation (pulse) signal, and whether or not the anti-theft device or the theft detection unit is operating normally. Enable or disable engine control operations.

The waveforms of the confirmation signal, theft signal, and the signal at the time of failure can be freely set at the Pm port. However, in the above embodiment, each waveform is set from the following viewpoints. did. The microprocessor or CPU that constitutes the theft detection unit can generate a signal with a preset frequency and duty ratio only when the microprocessor or C
Considering that it is only during normal operation of the PU, and that it is virtually impossible to generate a signal of the same frequency and duty ratio as described above due to improper operation, a confirmation signal indicating a valid key operation. Is a signal of a predetermined frequency and a duty ratio.

When the theft detection unit fails, the output level of the microprocessor or CPU constituting the theft detection unit is often unstable or indeterminate. Fixed to high level. The theft signal should be generated only during normal operation of the theft detection unit.
Signals can be clearly distinguished from each other.
The fixed low level was set in consideration of the connection of the type of signal to the engine control circuit 16. Of course, the output of the theft detection unit 22 at the time of failure may be fixed to a low level using a pull-down resistor instead of a pull-up resistor, and the theft signal may be set to a fixed high level.

The confirmation signal discriminating operation of the start permission signal generating means 16A to 16H in the engine control circuit 16 is as follows.
This will be described with reference to the functional block diagram of FIG. 2 and the flowchart of FIG. In the experiments of the present inventors, as a confirmation signal, the level is inverted every about 22 ms, a cycle of about 44 ms,
Since a pulse having a duty ratio of 0.5 is used, this confirmation signal determination process is executed, for example, every 10 ms by a timer interrupt of the engine control circuit 16. The period of the timer interrupt, that is, the sampling interval, is determined in relation to the period of the confirmation (pulse) signal, which is the detected signal. In general, according to a well-known sampling theorem, the interrupt period is half the pulse period. The following is acceptable.

In step S1 of FIG. 3, the voltage dividing resistor 2
Based on the divided voltage according to 8, 29, whether the vehicle is equipped with an anti-theft function, and if so, what is the type of the specification, in other words, where is the destination of the vehicle? Is determined. Since the present invention is not related to the destination determination, the following description is based on the assumption that only the presence or absence of the anti-theft function is determined. For example, if the divided voltage is 0
If v, it is determined that there is no anti-theft function, and if 4 v, it is determined that the anti-theft function is provided. This determination is performed by the anti-theft function determining section 16A in FIG. If it is determined that there is no theft prevention function, the process proceeds to step S14, and the engine start permission flag is set to 1. In FIG. 2, the anti-theft function determining section 16
A enables the start permission signal generation circuit 16G and causes the engine control unit 16K to execute engine start control.

When it is determined in step S1 that the anti-theft function is provided, it is determined in step S2 whether the determination end flag is 0, that is, whether the determination time described later has not expired. In FIG. 2, this corresponds to whether the determination timer 16C has timed out and generated an output. Since the determination end flag is initially 0, the process proceeds to step S3 to determine whether the determination timer start flag is 1 (ie, whether a timer for measuring an allowable determination time has been started). If the timer has not been started, the timer start flag is set to 1 at the same time as starting the timer in step S4, and the counter is preset to a predetermined value (3 in this example) in step S5. The process of FIG. 3 once returns to the main routine (not shown), and restarts the process of FIG. 3 at the next timer interrupt. These processes are
In FIG. 2, when the antitheft function determining section 16A determines that the antitheft function is present, this corresponds to activating the determination timing generation circuit 16B and the determination time timer 16C and presetting the counter 16F to an initial value.

In the subsequent processing, since the determinations in steps S1 to S3 are all affirmative, the process proceeds to step S6, and the time set in the determination time timer (2.2 in this example).
Second) has expired. Since it does not expire at first, it is determined in step S7 whether the signal level received at the Pm port of the engine control circuit has been inverted. This is because in FIG. 2, the level of the received signal detected by the signal level detection circuit 16D in accordance with the output of the determination timing generation circuit 16B is transferred to the level inversion detection circuit 16E via the switch 16S, and the level inversion detection circuit 16E Corresponds to detecting the reversal. The level inversion can be detected by temporarily storing the detection level at the previous sampling and comparing it with the detection level at the current sampling. If level inversion is not detected in step S7, the process returns to the main routine. Conversely, if level inversion is detected, 1 is subtracted from the current count value of the counter in step S8. In FIG. 2, the count value of the counter 16F is reduced by 1 by the output of the level inversion detection circuit 16E.

In step S9, the count value of the counter is 0.
Is determined, the determination is negative (count value is not 0)
If so, return to the main routine. If the count value becomes 0 while repeating the above processing, it can be determined that the ignition key used is valid. Therefore, the engine start permission flag is set to 1 in step S10, and further determined in step S11. The end flag is set to 1 to end the signal determination operation. On the other hand, if the determination in step S9 is not affirmative, and thus the determination time expires while the determination end flag is 0, the determination in step S6 becomes affirmative, and the process in FIG. 3 proceeds to step S12. This means that the determination time timer 16C in FIG. 2 generates an output by counting up, and the switch 16S is switched from the position shown to the opposite level determination circuit 16H.

In step S12, the port Pm is set at that time.
The level of the pulse signal being received is determined. If the level is high (Hi), the process proceeds to step S13.
It is determined that the theft detection unit 22 has failed and the fact is displayed (and an alarm is issued if necessary), the engine start permission flag is set to 1 in step S10, and the engine is started. On the other hand, if the received pulse signal is low level, the permission signal is not received by the theft detection unit 22, that is, it is determined that the ignition key operation is illegal, and the determination flag is set in step S11 while the engine start is not permitted. Set to 1 to end the determination operation. These processes are performed by the output of the signal level detection circuit 16D in FIG.
This is equivalent to energizing the start permission signal generating circuit 16G only at the time of a high level input. When the determination end flag is set to 1, the determination in step S2 is negative, and the other processes in FIG. 3 are skipped. In this way, the engine can be started and run when a proper ignition key operation has been performed or the theft detection unit 22 has failed. You.

FIG. 4 is a time chart for explaining the operation of the above embodiment. At the timing shown by the waveform (1), the level detection of the Pm port inputs (2a), (2b) and (2c) is performed. The waveform (2a) is a signal input to the port Pm when a valid key operation is performed, (2b) is a signal when an improper key operation is performed, and (2c) is a signal input to a port Pm when the theft detection unit 22 fails. . The waveforms (3a), (3b), and (3c) show the changing state of the counter count value in each case, and the waveforms (4a), (4b), and (4c) show the changing state of the start permission flag in each case. ing. See Figure 2 for details.
3 is obvious from the above description, and will not be described.

In the examples shown in FIGS. 3 and 4, if a predetermined number of level inversions are detected during a predetermined determination time, it is determined that the key operation is valid. There are concerns about the judgment. As a countermeasure, a timer means for measuring the time from the immediately preceding level inversion to the current level inversion and a resetting means (not shown) for the counter 16F are added to FIG. 2, and as shown in FIG.
Between step S7 and step S8 in FIG. 3, the time from the previous level inversion to the current level inversion is the set time T.
Procedure for determining whether the time is shorter than 0 ms (step S
71) is added, and when the judgment is negative, step S72 is added.
It is desirable to reset the counter 16F by the following. The set time T0 is an allowable maximum value of a time between two consecutive level inversions that occur in a normal confirmation signal. When the pulse duty ratio is set to 1/2,
It is 1/2 of the pulse period.

In the above, based on the fact that the level inversion of the confirmation signal received at the port Pm has been confirmed three times,
Although it is determined that the pulse signal is received, it will be easily understood that the number may be other times, for example, two or three or more times. Further, it is desirable that the theft detection unit 22 can be equipped so as to be insertable into and removable from the engine control circuit. By doing so, in the case of a vehicle with an anti-theft function, the anti-theft detection unit 22 is mounted, and in the case of a vehicle without the anti-theft function, the anti-theft detection unit 22 is not mounted. A common engine control circuit can be implemented in both vehicle types. Clearly,
In this case, in the case of a vehicle having no anti-theft function, a high-level potential is always supplied to the port Pm, so that there is no hindrance to starting the engine, as is apparent from the above description. .

In the above-described embodiment, the theft detection unit 22 receives, decodes, and collates a permission signal from a separately provided immobilizer, but the theft detection unit itself detects the key code ID, It goes without saying that decryption and collation may be performed, and an ID signal (confirmation signal) or a theft signal indicating that a valid starting operation is being performed may be generated.

[0026]

According to the present invention, the confirmation signal from the theft detection unit, the theft signal, and the signal at the time of failure of the theft detection unit can be connected to the engine control circuit with only one signal line.
When the anti-theft function is added to the engine control device (ECU), the change of the circuit pattern is minimized, and the cost increase can be suppressed, and the number of terminals and the size can be reduced.
When the engine can be started or traveled due to a malfunction of the theft detection unit, this is displayed (and / or warned) to notify the occupant and prompt the occupant to repair it, so that the anti-theft function can be maintained normally. It will be easier. If the theft detection unit can be inserted into and removed from the circuit board of the engine control device, the specifications of the engine control circuit (board configuration, processing software, etc.) are common regardless of whether the vehicle is equipped with an anti-theft device There is an advantage that can be made. In addition, a vehicle already equipped with an anti-theft device can be dealt with simply by adding a theft detection unit. Also, in the manufacturing process, whether or not the theft detection unit is added can be identified only by the appearance, so that the operation and inspection are simple and reliable.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a functional block diagram showing a configuration of a main part of one embodiment of the present invention.

FIG. 3 is a flowchart showing a confirmation signal determination operation performed by the apparatus shown in FIG. 2;

FIG. 4 is a time chart illustrating a confirmation signal determination operation performed by the apparatus of FIG. 2;

FIG. 5 is a diagram showing a procedure added to the flowchart of FIG. 3 for a confirmation signal determination operation according to another embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional vehicle anti-theft device.

[Explanation of symbols]

Reference numeral 16: engine control circuit 16A: anti-theft function determining section 16B: determination timing generation circuit 16C: determination time timer 16D: signal level detection circuit 16E: level inversion detection circuit 16F: counter 16G: start permission signal generation circuit 16H: level determination Circuit 16K: Engine control unit 1
7 Fuel injection valve 18 Fuel pump 20 Ignition control unit 21 Fault display unit 22 Theft detection unit 26 Noise removal circuit 28 Code discrimination circuit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yu Asakura 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside of Honda R & D Co., Ltd. (72) Inventor Akira Nagai 1-4-1 Chuo, Wako-shi, Saitama pref. (56) References JP-A-6-270764 (JP, A) JP-A-6-167154 (JP, A) JP-A-4-228333 (JP, A) (58) Fields surveyed ( Int.Cl. ⁶ , DB name) B60R 25/04

Claims (10)

(57) [Claims] And determining whether or not the signal supplied to the input is an ID signal indicating a valid starting operation.
If it is a valid ID signal, a confirmation signal is sent.
When the signal is not a D signal, a theft detection unit that generates a theft signal, and a start permission signal is generated in response to the confirmation signal, and when neither the confirmation signal nor the theft signal is input, the theft detection unit A vehicle anti-theft device comprising: a start permission signal generating unit that determines that the engine is not operating normally; and an engine control unit that controls the engine to operate normally in response to the start permission signal. The system further comprises a determination time timer means for generating a timer signal after a lapse of a scheduled signal determination time, wherein the start permission signal generation means responds to the generation of the timer signal and is connected to a port connected to a theft detection unit. And determining that the theft detection unit is not operating normally when neither the confirmation signal nor the theft signal is input. Vehicle anti-theft device. 2. The vehicle anti-theft system according to claim 1, wherein said starting permission signal generating means generates an engine starting permission signal when it is determined that said theft detecting section is not operating normally. apparatus. 3. The apparatus according to claim 2, further comprising a failure notifying unit, wherein the permission signal generating unit drives the failure notifying unit when it is determined that the theft detecting unit is not operating normally. 3. The vehicle antitheft device according to 1 or 2. 4. The vehicle antitheft device according to claim 1, wherein said confirmation signal is a pulse having a predetermined cycle and duty ratio. 5. The vehicle anti-theft device according to claim 1, wherein the theft signal is a fixed level DC signal. 6. The vehicle antitheft device according to claim 5, wherein said theft signal is a DC signal of one of a reference (ground) level and a fixed high level. 7. A connection line for connecting an output of the theft detection section to an input port of the start permission signal generating means, wherein one of a pull-up resistor and a pull-down resistor is connected. The vehicle antitheft device according to any one of claims 1 to 6. 8. A determination signal generator for generating a level determination timing signal for instructing a level determination timing of an output signal from a theft detector, the permission signal generator comprising: Signal level detecting means for generating a signal indicating the level of the output signal from the section, means for detecting the level inversion of the output signal and generating a level inversion signal, and counting the number of generated level inversion signals; A counter that generates an output when the count value reaches a predetermined value, and a start permission signal generation circuit that generates the engine start permission signal in response to the output of the counter. The vehicle antitheft device according to any one of claims 1 to 3. 9. The timer according to claim 1, wherein said permission signal generating means measures a time interval from the immediately preceding inversion of said output signal level to a current time, and resets said counter when said time interval exceeds a predetermined value. The vehicle anti-theft device according to claim 8, further comprising: 10. Determine whether the signal supplied to the input is an ID signal indicating a valid starting operation. If the signal is a valid ID signal, a confirmation signal is output. A burglar detection unit that generates a theft signal, a start permission signal generating unit that generates a start permission signal in response to the confirmation signal, and an engine that controls the engine to operate normally in response to the start permission signal. A control unit, wherein the start permission signal generation means includes: a determination timing signal generation circuit that generates a level determination timing signal that instructs a timing of a level determination of an output signal from the theft detection unit; Signal level detecting means for generating a signal indicating the level of the output signal from the theft detection unit; Means for generating a signal, a counter for counting the number of generated level inversion signals, and generating an output when the counted value reaches a predetermined value; and A vehicle starting anti-theft signal generating circuit.