Description: BACKGROUND OF THE INVENTION  1. Field of the Invention  The present invention relates to a vehicle anti-theft method for a vehicle that enables code-recognition and then engine ignition control. 2. Description of the Related Art Conventionally, in a car, a code signal transmitting means and a transmission switch are provided on an engine start key and a code signal transmitted from the key is received and recognized on a vehicle side in order to prevent theft. Some are provided with a possible ignition control device. For example, when starting the engine, insert the key into the cylinder lock, operate the transmission switch provided on the key at an arbitrary timing, and transmit a code signal unique to the key from code signal transmission means built in the key,
Whether the received code signal is correct or not is determined by a CPU provided in an ignition control device or the like on the vehicle side, and the ignition control is permitted only when it is correct. In the above-described ignition control device,
If the CPU runs away due to radio noise or the like, abnormal ignition control may be performed and the engine may be damaged.
A watchdog timer circuit for monitoring the state of the PU is provided, and the CPU is reset when an abnormality of the watchdog signal output at the time of runaway of the CPU is detected. In this case, if the CPU is reset, the code signal confirmation process also returns to the initial state. Therefore, even if the CPU is reset and returned instantaneously due to noise, the code signal is not recognized. Accordingly, the code signal recognition process is performed again, and there is a problem that the engine ignition control state cannot be quickly returned to.  However, there are cases where a person who intends to use the vehicle illegally short-circuits the power supply line without using a key switch to activate the engine control system. Forcing the CPU to run away with the electromagnetic noise generator or the like for the vehicle that has taken the code recognition measures as described above causes a problem that the CPU erroneously permits the ignition operation.  In order to solve such a problem, it is possible to prevent the CPU from permitting the engine ignition control by causing the CPU to malfunction due to noise in an attempt to start the engine illegally. In order to achieve this, in the present invention, the code signal transmitted from the code signal transmitting means is received by the receiving means provided in the vehicle, the CPU determines whether the code signal is correct or not, and determines that the code signal is a valid code signal. A vehicle anti-theft method for performing ignition control when recognized, comprising detecting a rotation state of an engine at the start of operation of the CPU, and determining that the rotation of the engine is not equal to or greater than a predetermined threshold. When the CPU cancels the recognition state of the legitimate code signal, enters the code signal reception waiting state, and performs the ignition control,
The presence or absence of an abnormality in the CPU is determined.
The CPU is reset and the rotation state of the engine is
It was detected . Embodiments of the present invention will be described below in detail with reference to specific examples shown in the accompanying drawings. FIG. 1 is a view schematically showing the structure of a key device for starting an engine to which the present invention is applied. In FIG. 1, a key 1 for starting an engine is used as a body panel 2 of a small motorcycle, for example.
2 shows a state where the key cylinder lock 3 is inserted into the key cylinder lock 3 attached to the key cylinder lock.  As shown in FIG.
a is provided with a transmission switch 4 operated at the time of transmission, an infrared light emitting unit 5 that emits, for example, an infrared signal when the transmission switch 4 is turned on, and a transmission confirmation LED 6 for displaying a transmitting state. ing. An infrared receiving section 7 for receiving an infrared signal from the infrared emitting section 5 in a state where the key 1 is inserted into the key cylinder lock 3 and turned to the ON position is attached to the body panel 2 on the vehicle side, In the body panel 2, there is provided a CDI unit 8 which is connected to the infrared receiving section 7 via a lead wire and is fixed by a bracket (not shown). As shown in FIG. 2, the key 1 is provided with a CPU 9 for controlling transmission of a code signal, and an ID storage unit 10 for storing a user ID as a code signal. When the ON signal of the transmission switch 4 is input, the CPU 9 reads the user ID from the ID storage unit 10 and emits the code signal from the infrared light emitting unit 5 as an infrared signal. The CDI unit 8 includes a CPU 12
And an ID storage unit 13 storing the same user ID as the key 1, a CDI basic circuit unit 14 for ignition control, and a power supply circuit unit 15. In the CPU 12, the key-side user ID received by the infrared light receiving section 7
Is compared with the code signal of the vehicle-side user ID stored in the ID storage unit 13 to determine whether the code signal is correct or not, and to perform digital ignition control. A power supply circuit 15 for supplying a power supply voltage of the CDI unit 8 is connected in parallel with a battery BT and an ACG 16 as a generator driven by an engine (not shown). Thereby, when the charge amount of the battery BT is sufficient, the power supply voltage is supplied from the battery BT, and when the charge amount of the battery BT is insufficient, or when the battery BT is in a discharged or unconnected state, the power supply voltage is supplied by the power generation of the ACG 16. You. The CPU 12 of the CDI unit 8 is connected to a watchdog timer circuit 17 for detecting an abnormality and resetting the CPU 12 when an abnormality occurs in the CPU 12 due to radio noise or the like. The holding means 18 is connected. The code recognition and holding means 18 is for holding a code-recognized result for a certain period of time even after the power is turned off when a code-recognized signal is output from the CPU 12. The CPU 12 recognizes that the voltage is equal to or higher than a predetermined threshold. As a result, it is possible to quickly return to the ignition control without performing a code signal recognition process again due to a momentary interruption of the CPU 12, or the like. A CDI circuit power supply section 14a for supplying a power supply voltage to the CDI basic circuit section 14 is provided, and a transistor circuit for controlling the operation of the CDI basic circuit section 14 via the CDI circuit power section 14a. Is provided. The switching circuit 19 is controlled by a signal output from an output terminal OUT and a cancel terminal CAN of the CPU 12, and supplies a power supply voltage to the CDI basic circuit unit 14 via the CDI circuit power supply unit 14a by a signal output from the terminal OUT. The terminal CAN controls the CDI circuit power supply section 14a to be turned off. An ignition timing signal is output from an ignition timing signal output terminal IGT of the CPU 12 to the CDI basic circuit section 14, and the CDI basic circuit section 1 is operated in accordance with the ignition timing signal.
In step 4, ignition control of an ignition coil (not shown) is appropriately performed. Also, the input terminal PLS of the CPU 12
A pulse signal from a pulser coil 16a provided in the ACG 16 is input. Note that the CDI unit 8 may be provided with some kind of visible light emitting unit for displaying the result of recognition of the user ID. In the engine ignition control device constructed as described above, at the start of operation, the key 1 is inserted into the key cylinder lock 3 and turned to the ON position, and the transmission switch 4 is turned on. A code signal is transmitted from the infrared light emitting unit 5 of the first embodiment. When the charge state of the battery BT is sufficient, turning the key 1 to the ON position activates the power supply circuit 15 and supplies the power supply voltage to the CDI unit 8 so that the code signal can be always received. When the transmission switch 4 is turned on in this state, the code signal is transmitted several times at predetermined intervals. The CPU 12 determines whether the code signal is correct or not. The ignition of the engine can be controlled by starting the starter. Next, control by the CPU 12 according to the present invention will be described below with reference to the flowchart of FIG. First, when the key 1 is inserted into the key cylinder lock 3 and turned to the ON position at the start of operation, the switch is turned on, the CDI unit 8 is turned on, and the CPU 12 is operated. When the CPU 12 starts operating, a reset process is first performed as shown in a first step ST1 of FIG. In the next second step ST2, it is determined whether or not the engine is rotating. The sensor for detecting that the engine is rotating may be a rotation sensor used for an engine tachometer or a vehicle speed sensor used for a vehicle speed meter, but may be used for ignition timing control. Whether the pulse signal has been generated within a predetermined time,
The rotation speed is preferably determined by the CPU 12 based on the pulse interval. By doing so, an additional circuit such as a dedicated sensor becomes unnecessary, and the circuit can be simplified, which is preferable. It is preferable that the threshold value for determination is set to a value not less than the rotation speed at the time of starting by the starter motor or at the time of kick starting, which is not determined to be during engine rotation. If it is determined that the engine is not rotating, it is determined that starting at the start of operation is to be performed, and the process proceeds to a third step ST3, where a cancellation process is performed on the code signal recognition and holding means 18. In this case, even if the code recognition holding means 18 is in the code recognized state,
Canceled. After performing the above-described cancel processing, the next fourth
In step ST4, a code signal receiving process is performed, and the next fifth
In step ST5, a code signal recognition process is performed to determine whether the code is a legitimate user code. In the fifth step ST5, the process of returning to the fourth step ST4 is repeated until the user code is recognized as a legitimate user code. If the user code is recognized as a legitimate user code as described above, the process proceeds to a sixth step ST6, where a signal for holding code recognition completion is output to the code signal recognition holding means 18. In the next seventh step ST7, the CPU 12 permits the CDI basic circuit section 14 to perform ignition control, and proceeds to an eighth step ST8. In the eighth step ST8, C
Check the abnormality of PU12. This abnormality is, for example, when an abnormality occurs in the watchdog signal from the CPU 12 due to radio wave noise or when the CPU 12 goes down due to power cutoff. If no abnormality has occurred, the process returns to the seventh step ST7 to continue the ignition control. When it is determined in the eighth step ST8 that an abnormality has occurred, the process returns to the first step ST1, and the CPU 12 is reset in the first step ST1. At this time, since the CPU 12 is abnormal, the code signal recognized output is inevitably turned off, and the first step ST1 is executed.
Will return to. Then, the process proceeds to the second step ST2, and the same steps as described above are performed again. However, when the CPU 12 is momentarily interrupted during running, the engine is rotating, and in such a case, the authorized user is once operated. It may be judged that it is after starting by recognizing that it is.
Therefore, if it is determined in the second step ST2 that the engine is rotating, the process proceeds to the sixth step ST6 without performing the code recognition process. Next, with reference to the time chart of FIG. 4, a process for preventing the CPU 12 from malfunctioning due to noise and starting the engine illegally to steal will be described below. In order to illegally start the engine, for example, the power line is directly connected to the power terminal of the CDI unit 8 and the CPU 12
When the is turned on, the code recognition is first checked by the reset processing based on the above flow, but since the operation is started, the code is not recognized, and the engine is in the stopped state in the determination that the engine is rotating. From
Subsequently, a code signal receiving process is performed. At this time, the ignition is not started because the legitimate code is not received in the code signal reception processing state due to the incorrect start. However, there is a case where a code recognition result is output as shown in FIG. 4 by generating radio noise by some means and causing the CPU 12 to run away and malfunction. Then, the code signal recognition and holding means 18 enters a holding state, and the runaway is detected by the watchdog timer circuit 17 to reset the CPU 12. However, in the subsequent code recognition check when the CPU 12 returns, it is determined that the code has been recognized. Is determined. On the other hand, in the present invention, as described above, it is first determined whether or not the engine is rotating. Since the engine does not rotate only by erroneous recognition of the CPU 12, the second after reset is executed. It is determined in step ST2 that the engine is not rotating. Therefore, the third
Proceeding to step ST3, the CPU 12 performs a cancel process in which the code has been recognized. Then, the code signal receiving process is performed again, and since the legitimate code signal cannot be transmitted at the time of fraud, the ignition control is not performed and theft can be prevented. FIG. 5 is a view corresponding to FIG. 2 showing a second embodiment according to the present invention. In the second embodiment, the same parts as those in the illustrated example are denoted by the same reference numerals, and detailed description thereof will be omitted. In the circuit of FIG. 5, the first relay RY1 is connected to the power supply voltage line to the CDI basic circuit unit 14.
Are provided, and the power supply voltage from the power supply circuit 15 is selectively supplied to the CDI basic circuit unit 14 by turning on / off the first relay RY1. The first relay RY1 is connected to the CPU 12
Is excited by a first transistor Q1 that can be turned on by an output signal of an output terminal OUT. Further, a second relay RY2 is provided for self-holding of the first relay RY1, and the second relay RY2 is provided.
Is excited via the second transistor Q2 which is turned on by an output signal from the terminal CAN of the CPU 12, and the self-holding state is released by the excitation. The same processing as described above can be performed in the circuit of FIG. 5 and is the same as the flow of FIG. 3, except that in the third step ST3 shown in FIG. , The transistor Q2 is turned on by the output of the cancel signal to perform a process of forcibly canceling the self-holding of the relays RY1 and RY2. Further, as the code-recognized output in the sixth step ST6 of FIG.
In this circuit, the relay RY is output by the output signal from the terminal OUT.
1 is turned on. At this time, if the cancel signal is not output from the terminal CAN, the relay RY1 is self-held as described above. Next, as in the above-described embodiment, the CPU
Referring to the time chart of FIG. 6, a process for preventing the engine 12 from malfunctioning due to noise and starting the engine illegally will be described below. For example, when the power supply line is directly connected to the power supply terminal of the CDI unit 8 and the CPU 12 is turned on, a check is performed during engine rotation. At this time, since the engine is in the stopped state, code signal reception processing is continuously performed. . Similarly to the above, the ignition control is not performed because the normal code is not received in the code signal reception processing state. However, the CPU 1
2 may malfunction, the code recognition result is output as shown in FIG. 6, and an ON signal is output from the terminal OUT. If the cancel signal is not output from the terminal CAN, the relay RY1 enters a self-holding state, and the runaway occurs in the watchdog timer circuit 1.
7 is detected and the CPU 12 is reset.
1 is maintained. When the CPU 12 returns thereafter, a check is made again that the engine is rotating. Therefore, since the engine is stopped, a cancel signal is output from the terminal CAN, and the self-holding of the relay RY1 is forcibly released. Then, the code signal receiving process is performed again, and since the normal code signal cannot be transmitted at the time of improper operation, the ignition control is not performed and the theft can be prevented as described above. In both of the specific examples, in response to a momentary interruption of the CPU 12 due to instantaneous noise during traveling, the CPU determines whether or not the engine is rotating before receiving the code signal and determining whether the code signal is correct or not. If it is determined that the engine is rotating, the engine ignition control is continued without performing the code recognition process. Therefore, there is no inconvenience that the engine must be stopped and the process at the time of starting operation must be performed again. As described above, according to the present invention, the reset processing by the watchdog timer circuit at the time of the occurrence of noise even when the CPU malfunctions due to noise and the code-recognized processing is performed. Since it is determined that the engine is not rotating, since the engine is not rotating except at the time of normal starting, it is determined that the engine is not rotating, so that ignition control is not performed. It is possible to preferably prevent the vehicle from being stolen due to unauthorized starting.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view schematically showing a configuration of an engine starting device to which the present invention is applied. FIG. 2 is a diagram showing a main circuit of the apparatus. FIG. 3 is a control flow diagram based on the present invention. FIG. 4 is a time chart showing an operation procedure according to the present invention. FIG. 5 is a view corresponding to FIG. 2 showing a second specific example. FIG. 6 is a view corresponding to FIG. 4 of a second specific example. [Description of Signs] 1 Key 1a Gripping unit 2 Body panel 3 Key cylinder lock 4 Transmission switch 5 Infrared light emitting unit 6 LED 7 Infrared light receiving unit 8 CDI unit 9 CPU 10 ID storage unit 12 CPU 13 ID storage unit 14 CDI basic circuit unit 15 power supply circuit section 16 ACG 16a pulser coil 17 watchdog timer circuit 18 code signal recognition and holding means
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