JP2007198220A - Non-contact ignition device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact ignition device with a simple circuit configuration at low cost by prohibiting ignition control until the internal combustion engine is stopped by controlling a microcomputer when a stop switch is operated. <P>SOLUTION: The microcomputer 15 comprises an output holding mode terminal P for connecting the self-returning stop switch 21 to a gland. When the output holding mode terminal P is connected to the gland by the stopping operation of the stop switch 21, a switching element 12 is triggered by a program for a predetermined time control the charging of a charging and discharging capacitor for ignition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contactless ignition device for an internal combustion engine that enables the misfire control of the ignition device for the internal combustion engine by operating a stop switch.

  Conventionally, the charge / discharge capacitor is charged with the induced voltage of the power generation coil in synchronization with the rotation of the internal combustion engine, and the charge of the charge / discharge capacitor is charged through the switching element that is turned on by the trigger signal generated based on the induced voltage of the trigger coil. There is provided a non-contact ignition device for an internal combustion engine that supplies an ignition coil and ignites a spark plug.

  Further, such a non-contact ignition device for an internal combustion engine is provided with an ignition stop circuit that can arbitrarily stop the ignition operation by operating a self-returning stop switch at the operator's discretion. Yes (see, for example, Patent Document 1).

The ignition stop circuit receives an induced voltage of the trigger coil via a voltage rectifier circuit and a voltage smoothing constant circuit, and maintains one stable operation state. The stop switch that short-circuits the power generation coil via the first switching element by performing a switch operation so as to be in an operating state.
JP 2004-169615 A

  However, in the conventional contactless ignition device for an internal combustion engine, the circuit configuration for setting the stop mode is complicated, and the assembly man-hour is increased and the assembly efficiency is lowered due to the use of a relatively large variety and quantity of parts. However, there is a disadvantage that it becomes an obstacle to cost reduction.

  The present invention was made to solve the conventional problems as described above. When the stop switch is operated, the misfire control is continued until the internal combustion engine is stopped by the control of the microcomputer. It is an object of the present invention to provide a contactless ignition device for an internal combustion engine that can realize this at a low cost with a simple circuit configuration.

  To achieve the above object, a contactless ignition device for an internal combustion engine according to the present invention includes a rotor having two magnetic poles arranged with a magnet interposed therebetween, and an exciter coil and a trigger coil wound around the rotor. Switching which supplies the charge of the ignition charge / discharge capacitor to the ignition coil, which is triggered by the induction voltage of the trigger coil and becomes conductive, and the charge / discharge capacitor for charging the positive induction voltage of the exciter coil A non-contact ignition device for an internal combustion engine having an element, and having an output holding mode terminal for connecting a self-returning type stop switch to a ground, and the output holding mode terminal by a stop operation of the stop switch Is connected to the ground, the switching element is controlled by a program to And gas, characterized in that it comprises a microcomputer for shunting the exciter coil.

  With this configuration, during startup and operation of the internal combustion engine, the induced voltage of the exciter coil is charged to the charge / discharge capacitor, while the advance or retard control pulse generated by the microcomputer based on the induced voltage of the trigger coil Thus, the switching element can be switched on.

  For this reason, the electric charge accumulated in the charge / discharge capacitor flows to the ignition coil during the switch-on period, sparks are generated in the spark plug, and the air-fuel mixture in the internal combustion engine can be ignited. continue.

  When the stop switch is turned on during the operation of the internal combustion engine, the output holding mode terminal that has been pulled up to the power supply potential of the microcomputer is connected to the ground via the stop switch.

  The microcomputer detects the ground potential, fixes the output for a set time by program control, and inputs a trigger signal to the switching element. For this reason, this switching element is switched on.

  When the switching element is switched on, the exciter coil is shunted, and charging of the charge / discharge capacitor is prohibited. Accordingly, the supply of the ignition voltage to the ignition coil is stopped, no discharge is generated in the spark plug, the internal combustion engine becomes misfired, and finally stops. However, if the output is continued by program control, the power consumption of the microcomputer increases, and the output cannot be fixed by the microcomputer until the internal combustion engine is stopped. In order to eliminate this state, the output is fixed to L0 when the rotational speed of the internal combustion engine falls to the set rotational speed. Thereby, the power source of the microcomputer can be secured until the internal combustion engine is stopped.

  Further, since the stop switch is an automatic return type, it is immediately switched off after the switch is turned on. However, the microcomputer switches on the switching element until the internal combustion engine decreases to the set rotational speed during the program control. to continue. After the internal combustion engine drops to the set speed, the output is stopped and the switching element is not switched on. Thereby, it is not necessary to hold down the stop switch. The program control is canceled when the power supply voltage of the microcomputer is turned off.

  The contactless ignition device for an internal combustion engine according to the present invention is characterized in that the trigger of the switching element by the microcomputer is executed until the internal combustion engine is stopped.

  This configuration is convenient because it is not necessary to hold down the stop switch when stopping the internal combustion engine. Further, when the internal combustion engine is surely stopped and used for a chainsaw or a mower, work hazards can be avoided.

  Further, the contactless ignition device for an internal combustion engine according to the present invention is configured such that when the potential of the output holding mode terminal is continuously reduced to the ground level by two times of the control pulse output by the microcomputer, the switching to the microcomputer is performed. A control output for the gate of the element is inputted.

  With this configuration, it can be accurately determined that the microcomputer is in the stop operation mode, and the rapid stop of the internal combustion engine can be safely performed at an arbitrary timing.

  The present invention provides a microcomputer with an output holding mode terminal for connecting a self-reset type stop switch between the microcomputer and the ground, and when the output holding mode terminal is connected to the ground by a stop operation of the stop switch, the switching is performed. The output to the element can be controlled by a program, and supply of the ignition voltage to the ignition coil can be stopped. Therefore, no discharge is generated in the spark plug, the internal combustion engine is in a misfire state, and finally the internal combustion engine can be stopped quickly and reliably.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a partially cutaway front view of a main part configuration of a contactless ignition device for an internal combustion engine according to an embodiment of the present invention. FIG. 2 shows a contactless ignition device for an internal combustion engine according to an embodiment of the present invention. It is a circuit diagram.

  In FIG. 1, a trigger coil 1 and an exciter coil 2 constituting a contactless ignition device are wound around both leg portions 8 a and 8 b of a U-shaped core 8. Here, the exciter coil 2 is wound around a leg portion 8b of the rotor 3 described later on the rotation direction 4 side, and the trigger coil 1 is wound around a leg portion 8a on the opposite side to the rotation direction.

  Further, the rotor 3 is arranged at a position facing the core 8 so as to be capable of high-speed rotation. The rotor 3 is made of a non-magnetic columnar block such as aluminum, and a pair of magnetic poles 6 and 7 are embedded in the columnar block with a magnet 5 interposed therebetween.

  A part of the magnetic poles 6 and 7 is exposed on the outer periphery of the rotor 3, and can pass through the end surfaces of both the leg portions 8 a and 8 b of the core 8 while the rotor 3 is rotating. Further, the end surfaces of both the leg portions 8 a and 8 b of the core 8 are formed in an arc shape so that a gap (distance) having a constant width can be held with respect to the outer peripheral surface of the rotor 3.

  In addition, the size and installation interval of the magnetic poles 6 and 7 and the size and interval of both the leg portions 8a and 8b of the core 8 are set according to the charge / discharge timing and trigger timing of the charge / discharge capacitor 10 described later.

  FIG. 2 is a circuit diagram showing a contactless ignition device for the internal combustion engine. In the figure, a diode 9, an ignition charging / discharging capacitor 10 and a primary coil 11a of an ignition coil 11 are connected in series to the exciter coil 2, and these generate a positive voltage induced by the exciter coil 2 in the ignition charging / discharging capacitor 10 Constitutes a charging circuit for charging.

  The ignition charge / discharge capacitor 10 is connected in series with the anode / cathode of the thyristor 12 as a switching element and the primary coil 11a of the ignition coil 11. The thyristor 12 and the ignition coil 11 constitute a discharge circuit that discharges the charge of the ignition charge / discharge capacitor 10 to the primary coil 11 a of the ignition coil 11.

  According to this, when the thyristor 12 is triggered and becomes conductive, the charge of the ignition charge / discharge capacitor 10 is discharged to the ignition coil 11. The thyristor 12 also functions to prevent charging of the ignition charge / discharge capacitor 10 by shunting the exciter coil 2 by a trigger.

  Further, a spark plug 13 is connected to the secondary coil 11 b of the ignition coil 11. Further, between the anode and the cathode of the thyristor 12, a backflow preventing diode 14 that also serves to charge the charge / discharge capacitor 10 is connected.

  On the other hand, both terminals of the trigger coil 1 are connected to a microcomputer 15 as control means for outputting a control pulse. The microcomputer 15 controls charging and discharging of the charge / discharge capacitor 10. Therefore, the output terminal of the microcomputer 15 is connected to the gate of the thyristor 12 for inputting the control pulse.

  Further, the microcomputer 15 shapes the voltage induced by the trigger coil 1, performs digital conversion, performs signal processing according to a predetermined program, and inputs the obtained control pulse to the gate of the thyristor 12. To function.

  A stop terminal 20 is connected to the power supply terminal 16 of the microcomputer 15 via a resistor 17 and diodes 18 and 19. A self-return type stop switch 21 is connected between the stop terminal 20 and the ground.

  The connection point of the diodes 18 and 19 is connected to the output holding mode terminal P of the microcomputer 15 and is connected to the anode of the diode 14 and one end of the exciter coil 2 via the diode 22. In addition, a noise countermeasure diode 23 is connected between the output holding mode terminal P and the power supply terminal 16.

  Next, the operation of the contactless ignition device for the internal combustion engine will be described with reference to the timing chart of each part of the circuit shown in FIG. Here, the ignition control operation of the internal combustion engine will be described first, and then the stop control operation of the internal combustion engine will be described.

  First, when the internal combustion engine is operated and the rotor 3 rotates in the direction of the arrow 4 in FIG. 1, the trigger coil 1 and the exciter coil 2 on the core 8 facing the rotor 3 are provided with FIGS. Each voltage of the waveform shown in FIG.

  Of the induced voltage of the exciter coil 2, a positive voltage is applied to the charge / discharge capacitor 10 for ignition via the diode 9 and the primary coil 11 a of the ignition coil 11, and the charge / discharge capacitor 10 for charge is charged. Is charged. As shown in FIG. 3G, this charged charge is held until a discharge timing described later.

  On the other hand, the induced voltage of the trigger coil 1 falls by a predetermined period from the rising of the positive induced voltage of the exciter coil 2 and is input to the microcomputer 15.

  The microcomputer 15 shapes the induced voltage of the trigger coil 1 and generates two positive input pulses p1 and p2 as shown in FIG. 3B from positive and negative voltages exceeding the set level, and FIG. Each positive input pulse p3 as shown in c) is extracted and recognized.

  Here, FIG. 3B is the positive pulses p1 and p2 obtained based on the positive input voltage of FIG. 3A, and FIG. 3C is the negative pulse of FIG. This is a positive pulse p3 obtained based on the input voltage. The pulse p3 is located between the two pulses p1 and p2.

  At the start of the internal combustion engine, the microcomputer 15 outputs a control pulse p5 as shown in FIG. 3 (d) in synchronization with the recognized input of the pulse p3 as shown in FIG. 3 (c). Is input to the gate of the thyristor 12. The control pulse p5 is used for discharging the charge of the charge / discharge capacitor 10 at the next rotation cycle of the internal combustion engine.

  Therefore, when the thyristor 12 is triggered by the output of the control pulse p5, the charge charged in the charge / discharge capacitor 10 one cycle before is discharged to the primary coil 11a of the ignition coil 11 through the anode and cathode of the thyristor 12. Is done. For this reason, a high voltage is instantaneously applied to the secondary coil 11b, a spark is generated in the spark plug 13, and the air-fuel mixture in the internal combustion engine is ignited.

  The ignition of the air-fuel mixture by the control pulse at the start of the internal combustion engine is performed for, for example, about 2 to 6 revolutions at the start of the internal combustion engine. As a result, the rotation of the internal combustion engine rises smoothly and gradually increases to the rotation speed of the normal operation mode (main mode).

  On the other hand, when the internal combustion engine is started and the rotational speed gradually increases, the microcomputer 15 generates the control pulse p4 shown in FIG. 3 (f) based on the recognized pulse p1 shown in FIG. 3 (b). The control pulse p4 is input to the gate of the thyristor 12. Note that the microcomputer 15 stops the output of the control pulse p5 in synchronization with the input of the control pulse p3 after about 2 to 6 rotations at the time of starting, and generates the control pulse p4 based on the pulse p1. Switch.

  The control pulse p4 is controlled by signal processing by the microcomputer 15 so as to be located within a time t1 from the rising timing of the pulse p1 to the rising timing of the pulse p2.

  The time t1 from the rising timing of the pulse p1 to the rising timing of the pulse p2 is information on the rotational speed (rotational speed) of the internal combustion engine, and the position (time t2) of the control pulse p4 within the time t1 is also the internal combustion engine. Information on the engine speed.

  The control pulse p4 is input to the gate of the thyristor 12 to trigger it, and becomes a control signal for determining the discharge timing of the charge / discharge capacitor 10, that is, the ignition timing of the internal combustion engine. Therefore, this control signal becomes information for determining the rotational speed of the internal combustion engine.

  By moving the control pulse p4 in the advance direction <arrow S direction) or the retard direction (arrow R direction) by digital processing by the microcomputer 15 with respect to the pulse p1, the ignition timing of the internal combustion engine is set to the user. Can be freely set according to the characteristics of the internal combustion engine.

  The microcomputer 15 grasps the current internal combustion engine speed by measuring the time t1, and arbitrarily sets the time t2 based on the first pulse p1 waveform obtained from the trigger coil 1 after one cycle. Thus, the charge of the charge / discharge capacitor 10 is discharged as shown in FIG.

  Thereby, the ignition timing of the internal combustion engine is controlled. This time t2 (ignition timing) can be arbitrarily set for each engine speed by digital signal processing by a program.

  Therefore, when the microcomputer 15 switches the position of the control pulse p4 according to a program and the speed of the internal combustion engine rises sufficiently and then recognizes a deceleration operation, the speed of the internal combustion engine is preset according to the program. The idling speed can be kept stable. In addition, after that, it is possible to quickly start up to the target rotational speed in a timely manner according to the program.

  In this way, by setting the time t2 in a fixed or arbitrary manner in advance in the program, the timing for supplying the ignition voltage to the spark plug can be adjusted, and the rotational speed of the internal combustion engine can be set and changed. . As a result, for example, it is possible to easily carry out the rapid response control of the internal combustion engine rotation from the high speed region to the idling region or the prevention of over-rotation of the internal combustion engine.

  Next, the stop control operation of the internal combustion engine will be described.

  During the operation of the internal combustion engine as described above, a power supply voltage (for example, +5 V) is applied to the output holding mode terminal P of the microcomputer 15.

  For this reason, the microcomputer 15 is not in the stop mode operation, and the control pulse p4 shown in FIG. 3 (f) is input to the gate of the thyristor 12, and the ignition operation of the spark plug 13 as described above is continued.

  The microcomputer 15 monitors that the potential of the output holding mode terminal P is lowered to the ground as shown in FIG. 3E by the push-on operation of the stop switch 21. When the microcomputer 15 detects that the potential of the output holding mode terminal P is continuously decreased by two times of the control pulse p4, the microcomputer 15 rotates the internal combustion engine to the gate of the thyristor 12. Outputs continuously while the number drops to the set speed.

  During the period in which this control signal is continuously output, the gate of the thyristor 12 is triggered, and the thyristor 12 shunts the exciter coil 2 so that the charging / discharging capacitor 10 is not charged. However, if the output is continued by program control, the power consumption of the microcomputer 15 increases, and the output of the microcomputer 15 cannot be fixed until the internal combustion engine is stopped. In order to eliminate this state, the output is fixed to L0 when the rotational speed of the internal combustion engine falls to the set rotational speed. As a result, the charging / discharging capacitor 10 is charged. However, since the microcomputer 15 does not output by program control, the thyristor 12 is not triggered and the internal combustion engine becomes misfired and stops quickly and safely. To do.

  Since the stop switch 21 is a self-returning type, it is immediately released (turned off) after the push-on operation, and the potential of the output holding mode terminal P quickly recovers. However, the microcomputer 15 makes an input to the thyristor 12. Since it is controlled, the stopped state of the internal combustion engine is maintained. If the power supply voltage of the microcomputer 15 falls below the operating voltage of the microcomputer 15 while this stop state is maintained, the stop holding mode is canceled.

  Therefore, after that, by starting the internal combustion engine, a power-on reset works, and the operation of the internal combustion engine by the control pulse p4 generated by the pulses p1, p2, and p3 can be resumed.

  As described above, according to the present embodiment, the microcomputer 15 is provided with the output holding mode terminal P for connecting the self-return type stop switch 21 to the ground, and the output is performed by the stop operation of the stop switch 21. When the holding mode terminal P is connected to the ground, the microcomputer fixes the control input to the thyristor at a high level by program control, so that charging of the charge / discharge capacitor 10 can be regulated reliably and rapidly, and therefore the internal combustion engine. Can be stopped quickly. Further, this operation can be realized at a low cost by a simple circuit configuration.

  A non-contact ignition device for an internal combustion engine according to the present invention has a simple and low-cost circuit configuration, and stops the supply of ignition voltage to the ignition coil when the stop switch is operated, so that the internal combustion engine is in a misfire state until the internal combustion engine stops. The present invention is useful as a non-contact ignition device for an internal combustion engine that has an effect of being able to hold and enables misfire control of the ignition device for the internal combustion engine by a stop switch operation.

1 is a partially cutaway front view of a main part configuration of a contactless ignition device for an internal combustion engine according to an embodiment of the present invention. 1 is a circuit diagram showing a contactless ignition device for an internal combustion engine according to an embodiment of the present invention. 3 is a timing chart showing signal waveforms at various parts of the circuit in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Trigger coil 2 Exciter coil 3 Rotor 5 Magnet 6, 7 Magnetic pole 8 Core 10 Charging / discharging capacitor | condenser 11 Ignition coil 12 Thyristor (switching element)
13 Spark plug 15 Microcomputer (control means)
21 Stop switch P Output hold mode terminal

Claims (3)

A rotor having two magnetic poles arranged with a magnet interposed therebetween, a core arranged opposite to the rotor and wound with an exciter coil and a trigger coil, and charging / discharging for ignition charging a positive induced voltage of the exciter coil A non-contact ignition device for an internal combustion engine having a capacitor and a switching element that is triggered by an induced voltage of the trigger coil to be conductive, and that supplies a charge of the ignition charge / discharge capacitor to the ignition coil. An output holding mode terminal for connecting a self-return type stop switch in between, and when the output holding mode terminal is connected to the ground by a stop operation of the stop switch, the switching element is controlled by a program, and the exciter It is equipped with a microcomputer that shunts the coil. Non-contact ignition system for an internal combustion engine to be. 2. The contactless ignition device for an internal combustion engine according to claim 1, wherein the trigger of the switching element by the microcomputer is executed until the internal combustion engine is stopped. The microcomputer controls and inputs the output of the microcomputer to the gate of the switching element when the potential of the output holding mode terminal continuously decreases to the ground level for two times of the control pulse output by the microcomputer. The contactless ignition device for an internal combustion engine according to claim 1.

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