CN1051600C - Engine igniting circuit used for vehicles - Google Patents

Abstract

The present invention provides a vehicle engine ignition device which is difficult to start an engine by an unauthorized method. When the ignition switch is in the off state shown in the figure, the points a and b are closed, the capacitor C1 is charged by the battery, and the potential of point e becomes 12V. When the ignition switch is turned on to close the points c and d, the potential at point f becomes 12V, and the potential at point e becomes 24V. As a result, the Zener diode ZD1 breaks down, the current flows through the resistors R2 and R3, the transistor TR is turned on, and the potential of the ignition permission signal terminal of the control unit connected to the collector becomes 0V which is close to the ground potential. Then, the control unit drives the ignition coil through the silicon controlled rectifier SCR, discharges the spark from the spark plug, and starts the engine.

Description

Vehicle engine ignition circuit

The invention relates to an engine ignition circuit for a vehicle in which an ignition switch is arranged between a battery and an ignition unit, and the ignition unit is used to drive an ignition coil by closing the ignition switch, thereby starting the engine.

The vehicle engine ignition circuit has an ignition switch provided between the battery and the ignition unit. By using a regular ignition key to close the ignition switch, the ignition unit drives the ignition coil to start the engine.

In such an engine ignition circuit, the engine cannot be started by short-circuiting a specified wire among the wires connected to the ignition switch. This proposal uses a voltage detection circuit to detect the current flowing from the battery due to the ignition switch being closed. The voltage value at both ends of the resistance, when the detected voltage value is within the specified range, the ignition device is allowed to drive the ignition coil (see Japanese Patent Laid-Open Publication No. 4-318284). According to this proposal, if a regular ignition key is not used, even if the ignition unit is energized, the voltage detection circuit cannot detect a voltage value within a specified range, so the ignition unit is prohibited from driving the ignition coil, thereby preventing the engine from starting.

However, in the above-mentioned prior art, the voltage value that the ignition device is allowed to drive the ignition coil can be calculated by measuring the resistance value of the above-mentioned resistor by using a simple tool such as a tester.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a vehicle engine ignition circuit in which it is difficult to start the engine without using a regular ignition key.

In order to achieve the above object, the present invention is characterized in that: in the vehicle engine ignition circuit in which the ignition switch is arranged between the battery and the ignition unit, and the ignition unit is used to drive the ignition coil to start the engine by closing the ignition switch, the ignition device has An electric storage circuit that stores electricity by turning off the ignition switch, a voltage value forming device that forms a voltage different from the voltage of the battery based on the voltage stored in the electric storage circuit and the voltage of the battery, and when formed by using the voltage value forming device A control device that drives the ignition coil when the voltage is within a specified range.

According to the above structure, when the ignition switch is turned off, the power storage device stores electricity, and when the ignition switch is turned on, when a specified voltage different from the voltage of the battery is formed based on the voltage stored in the power storage device and the voltage of the battery, the ignition device is driven. ignition coils to start the engine. Since it is difficult to estimate a predetermined voltage different from the battery voltage, the engine cannot be started without using a regular ignition key.

(Example)

Next, a first embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a circuit diagram of the first embodiment.

Fig. 2 is a time chart of the first embodiment.

Fig. 3 is a circuit diagram of the second embodiment.

Fig. 4 is a circuit diagram of a third embodiment.

Fig. 1 is the engine ignition device that two-wheel motorcycle is used, and this engine ignition device is by the battery 1 that has 12V terminal voltage, utilizes the ignition switch 2 that ignition key carries out opening and closing, uses the ignition unit 3 of microprocessor, ignition coil 4 and The spark plug 5 of the engine constitutes.

The negative end of the battery 1 is connected to the vehicle body and grounded, and the positive end is connected to the ignition switch 2 through the fuse 6 . When the ignition switch 2 is turned off, points a and b are closed, and at the same time, points c and d are disconnected. When the ignition switch 2 is turned on, points a and b are disconnected, and at the same time, points c and d are closed.

The control unit 7 of the ignition unit 3 has a power supply terminal 8 , an ignition permission signal terminal 9 , and a trigger terminal 10 . The capacitor C1 is connected between points e and f, the resistor R1 is connected between points f and g, and the point f is connected to the power supply terminal 8 of the control unit 7 . Zener diode ZD1, resistor R2, and resistor R3 are connected in series between point e and point g. The base of the transistor TR is connected between the resistors R2 and R3, the collector is connected to the resistor R4 and the ignition permission signal terminal 9 of the control unit 7, and the emitter is connected to the point g.

The ignition coil 4 has a primary coil 12 connected to the high-voltage circuit 11 via a capacitor C2 and a secondary coil 13 connected to the spark plug 5 . A silicon controlled rectifier (thyristor) SCR is connected between the primary coil 12 and the ground, and the silicon controlled rectifier SCR is connected to the trigger terminal 10 of the control unit 7 .

Next, the operation of the embodiment of the present invention having the above-mentioned structure will be described with reference to FIG. 2 .

When the ignition switch 2 is in the OFF state as shown in the figure, the points a and b are closed, and the current flows from the battery 1 to the capacitor C1 through the resistor R1, and charges the capacitor C1 after a specified time. As a result, the potential at point f becomes 0 V which is the ground potential, and the potential at point e becomes 12 V which is equal to the terminal voltage of battery 1 . At this time, since the breakdown voltage of the Zener diode ZD1 is set to a specified value higher than 12V and lower than 24V, the Zener diode ZD1 will not break down, thereby preventing the discharge of the capacitor C1.

When the ignition switch for starting the engine is turned on from this state, since point a and point b are disconnected, and point c and point d are closed, the potential of point f connected to the positive terminal of battery 1 becomes 12V. As a result, since the potential at point e becomes 24V, which is 12V higher than the potential at point f, Zener diode ZD1 breaks down, and current flows from point e to point g through Zener diode ZD1, resistor R2, and resistor R3. In this way, the current flows to the base of the transistor TR, and the transistor TR is turned on, and the current flows from the control part 7 to the ground point g through the resistor R4 and the collector and emitter of the transistor TR, so that the ignition of the control part 7 is permitted. The potential of the signal terminal 9 becomes 0 V close to the ground potential.

In this way, when the potential of the ignition permission signal terminal 9 becomes close to 0V, the control unit 7 judges that the ignition switch 2 has been turned on by a regular ignition key, and the silicon controlled rectifier SCR is activated at a specified time through the trigger terminal 10 . As a result, the discharge current of the capacitor C2 flows through the primary coil 12 of the ignition coil 4, a high voltage is generated in the secondary coil 13, and spark discharge occurs in the spark plug 5 to start the engine.

Like this, when using regular ignition key to turn on ignition switch 2, just can start engine. In addition, in order to start the engine without using the ignition key, the potential of point e must be consistent with the specified value higher than 12V and lower than 24V. However, it is necessary to measure the capacitance of the capacitor C1 for this purpose, and since the capacitance of the capacitor C1 cannot be simply measured with a tool such as a tester, it is difficult to start the engine by an informal method.

Next, a second embodiment of the present invention will be described with reference to FIG. 3 .

In the second embodiment, a resistor R5 and a resistor R1 are connected in series between points f and g in the first embodiment, and a capacitor C3 is connected in parallel to the resistor R1.

According to the second embodiment, when the ignition switch 2 is in the disconnected state shown in the figure, the points a and b are closed, the capacitor C1 is charged, the potential at point e becomes 12V equal to the terminal voltage of battery 1, and the potential at point f becomes The potential becomes 0 V equal to the ground potential. When the ignition switch 2 for starting the engine is turned on, point a and point b are disconnected, and points c and point d are closed. Therefore, while charging the capacitor C3, the potential of point f is gradually increased. When the capacitor C3 is fully charged When electrified, the potential at point f becomes 12V (see the dotted line in Figure 2).

As a result, since the potential at point e becomes 24V which is 12V higher than the potential at point f, Zener diode ZD1 breaks down as in the first embodiment, current flows from point e to point g, transistor TR is turned on, and ignition The potential of the permission signal terminal 9 becomes 0V. Then, the control unit 7 determines that the ignition switch 2 has been turned on by a normal ignition key, and drives the ignition coil 4 to start the engine.

Thus, also in the second embodiment, it is possible to reliably prevent the engine from being started by an unauthorized method. In addition, as shown by the dotted line in FIG. 2, when the ignition switch 2 is turned on, if it is judged that the potential at point e rises from 12V to 24V, if the ignition coil 4 is allowed to be driven, it is assumed that the ignition coil 4 is simply turned on by an informal method. If the specified voltage is applied to point e, the engine cannot be started because the potential rising line of point e is different.

Next, a third embodiment of the present invention will be described with reference to FIG. 4 .

In the third embodiment, the Zener diode ZD2 is connected between the points a and b of the ignition switch 2, and the capacitor C4 is connected between the points e and g. Then, the potential at point e and the reference potential obtained by dividing the battery voltage by the resistors R6 and R7 are input to the window comparator circuit IC1.

According to the third embodiment, when the ignition switch 2 is in the OFF state shown in the figure, the points a and b are closed, the capacitor C4 is charged, and the potential of the point e becomes 12V equal to the terminal voltage of the battery 1 . When the ignition switch 2 for starting the engine is turned on, since point a and point b are disconnected, and point c and point d are closed, if the breakdown voltage of Zener diode ZD2 is selected as, for example, 2V, the voltage of point e The potential becomes 10V obtained by subtracting the aforementioned breakdown voltage 2V from the terminal voltage 12V of the battery 1 .

As a result, when the difference between the reference potential and the potential at point e becomes a predetermined value, an ignition permission signal is output from the window comparator circuit IC1 to the ignition permission signal terminal 9 of the control unit 7, and the control unit 7 judges that the ignition switch 2 has been activated. The regular ignition key is engaged, allowing the engine to be started.

In this way, since starting of the engine is permitted only when a predetermined voltage lower than the terminal voltage of the battery 1 is established, it is possible to prevent the engine from being started by an unofficial method.

The embodiments of the present invention have been described above in detail, but various design changes can be made in the present invention without departing from the gist.

For example, the vehicle engine ignition circuit of the present invention can be applied to four-wheeled automobiles as well as two-wheeled motorcycles.

As described above, according to the present invention, the ignition coil can be driven by the ignition unit to start the engine only when the electric storage device and the battery have a specified voltage different from the voltage of the battery by turning off the ignition switch. Even if you want to start the engine without the ignition switch, it is difficult to easily measure the electric capacity of the power storage device, so the above-mentioned specified voltage cannot be formed. Therefore, it is possible to reliably prevent the engine from being started by an unofficial method.

Claims (1)

1. An ignition switch is arranged between the battery and the ignition unit, the ignition unit is used to drive the ignition coil by the closure of the ignition switch, and then the vehicle engine ignition circuit for starting the engine is characterized in that: the above ignition unit has a The power storage circuit that is disconnected and stored, the voltage value forming device that forms a voltage different from the voltage of the battery based on the voltage stored in the power storage circuit and the voltage of the battery, and when the voltage formed by the voltage value forming device is within a specified range When it is inside, it drives the control device of the ignition coil.

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