JP4159050B2 - Engine ignition device - Google Patents

Description

  The present invention relates to an ignition device for an engine, and more particularly to an ignition device used for a relatively small engine.

  As an ignition device used for a comparatively small engine, a permanent magnet is arranged on the outer periphery of the flywheel of the engine, and an ignition coil (ignition coil) comprising a primary coil and a secondary coil at a position facing the outer periphery of the flywheel. A so-called self-trigger type in which an iron core wound around the primary side is arranged is widely known (Japanese Utility Model Publication No. 63-21739, Japanese Patent Publication No. 5-42629).

  In the self-trigger type ignition device, the following countermeasures (a) to (c) are necessary because of the attachment of a permanent magnet to a rotor such as a flywheel, and each has problems.

  (A) In order to balance the rotation of the rotor, it is necessary to provide a counterweight having a weight equivalent to that of the permanent magnet portion, which makes the rotor heavy.

  (B) It is necessary to devise the attachment structure and attachment method of the permanent magnet and the counterweight so as to withstand the centrifugal force caused by the high-speed rotation of the rotor.

  (C) Since the attachment portions such as the permanent magnet and the counterweight have a portion protruding toward the inner periphery of the rotor, it is difficult to use the space inside the rotor.

In response to the above problems, the present applicant, as shown in Japanese Patent Application Laid-Open No. 2000-171736, arranges an iron core at a position facing the outer peripheral surface of a rotor that rotates in synchronization with engine rotation, and ignites this iron core for ignition. An ignition device is proposed in which a primary magnet and a secondary coil are wound, a permanent magnet is attached, and an inductor is disposed on the rotor side.
Japanese Utility Model Publication No. 63-21739 Japanese Patent Publication No. 5-42629 JP 2000-171736 A

  Although the above-mentioned problems (a) to (c) of the ignition device described in Patent Documents 1 and 2 have been solved by the ignition device described in Patent Document 3, the induced voltage is used in a part of the induced range. Then, since it is immediately used as ignition energy, there is a problem that the restriction on the ignition timing range is large and it is difficult to cope with the case where a large ignition energy is required.

  The present invention has been made to solve this problem, and an object of the present invention is to provide an ignition device that can effectively use generated energy to meet a large ignition energy requirement.

  The present invention includes an iron core disposed at a position facing an outer peripheral surface of a rotor that rotates in synchronization with the rotation of the engine, and an exciter coil wound around the iron core, the ignition being synchronized with the rotation of the engine In an engine ignition device that performs an ignition operation with generated power induced in the exciter coil at a timing, a permanent magnet incorporated in the iron core, and a closed magnetic circuit of magnetic flux generated by the permanent magnet provided in the rotor An inductor to be formed, and a capacitor that is charged with the generated energy induced in the exciter coil when the inductor passes through an opposing portion of the iron core as the rotor rotates, and at the ignition timing, the capacitor A first feature is that it includes an ignition circuit configured to discharge a capacitor and perform an ignition operation.

  In addition, the present invention has a second feature in that the inductor is provided at a plurality of locations on the outer peripheral surface of the rotor.

  In addition, the present invention has a third feature in that it includes trigger forming means for inputting a discharge trigger of the capacitor as an external signal to the ignition circuit.

  According to the present invention having the first feature described above, electric charge is accumulated in the capacitor with the generated energy generated by the exciter coil, and the accumulated electric charge is used as ignition energy, so that the generated little energy is effectively utilized. be able to.

  Further, according to the second feature, even when large ignition energy is required in a large-sized engine or the like, electric charges are accumulated with energy generated each time a plurality of inductors pass through opposite positions of the iron core. Thus, large energy can be easily obtained. Therefore, for example, large energy can be supplied to the primary side of the ignition coil, and the rising speed of the secondary side voltage can be increased.

  Further, according to the third feature, the ignition timing can be freely set by an external signal.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing a main configuration of an ignition device according to an embodiment of the present invention. In FIG. 1, a rotor 1 is, for example, a flywheel connected to a crankshaft 2 of an engine (not shown), and rotates in a direction indicated by an arrow R in synchronization with the rotation of the engine. An exciter 3 is disposed at a position facing the outer peripheral surface of the rotor 1.

  The iron core 4 of the exciter 3 has three magnetic poles 5, 6, 7 having one end connected to each other and the other end opened to form an alphabet “E” shape as a whole. The iron core 4 is configured by laminating a plurality of electromagnetic steel sheets punched into the “E” shape. An exciter coil 8 is wound around a magnetic pole 6 at the center of the iron core 4 via a bobbin 9 made of an insulating material.

  Permanent magnets 10 are embedded near the tips of the magnetic poles 5, 7, that is, near the outer peripheral surface of the rotor 1. A hole into which the permanent magnet 10 can be inserted at the time of punching of the electromagnetic steel sheet constituting the iron core 4 is simultaneously formed, and the permanent magnet 10 is fitted into the formed hole after the steel sheets are laminated. The permanent magnet 10 is desirably a rare earth magnet such as Nd—Fe—B (neodymium-iron-boron). The permanent magnets 10 and 10 incorporated in the magnetic poles 5 and 6 are arranged so that their polarities are in the opposite directions. For example, the permanent magnet 10 in the magnetic pole 5 has an S pole on the side close to the rotor 1 and the N pole on the side far from the rotor 1, while the permanent magnet 10 in the magnetic pole 7 has an S pole on the side far from the rotor 1. The side close to the rotor 1 is the N pole.

  An inductor 11 made of a magnetic plate is fixed to the outer peripheral surface of the rotor 1. The inductor 11 is connected between the magnetic poles 5 and 6 or between the magnetic poles 6 and 7 according to the position of the rotor 1, and magnetic fluxes Φ1 and Φ2 by the permanent magnet 10 (magnetic flux Φ2 will be described later with reference to FIG. 2). Form a road. The inductor 11 is set to the length shown in FIG. 1 so that the open magnetic path between the magnetic poles 5 and 6 or between the magnetic poles 6 and 7 does not simultaneously become a closed magnetic path.

  FIG. 2 is a front view of the ignition device in the second position. In FIG. 2, the rotor 1 rotates in the direction of arrow R from the first position shown in FIG. 1, and the inductor 11 reaches the second position facing the magnetic poles 6 and 7. When the inductor 11 is in this second position, the permanent magnet 10 embedded in the magnetic pole 7 forms a magnetic flux Φ 2 that passes through the magnetic pole 7, the inductor 11, and the magnetic pole 6.

  As described with reference to FIGS. 1 and 2, the directions of the magnetic fluxes Φ <b> 1 and Φ <b> 2 passing through the exciter coil 8 are opposite to each other due to the arrangement of the polarities of the permanent magnets 10 and 10. Therefore, the direction and the number of magnetic fluxes passing through the exciter coil 8 vary depending on the position of the inductor 11 relative to the iron core 4, that is, the rotational position of the rotor 1.

  FIG. 3 is a diagram illustrating an example of an ignition circuit including the exciter coil 8. In the figure, both ends of the exciter coil 8 are connected to the primary side coil T1 of the ignition coil 12. A thyristor 13 is connected between the exciter coil 8 and the primary side T1 of the ignition coil 12. A rectifier diode 14 and a backflow preventing diode 15 are connected between the exciter coil 8 and the primary coil T1 of the ignition coil 12. A capacitor 17 is connected between a connection point between the thyristor 13 and the diode 14 and a connection point between the diode 15 and the primary coil T1. A gate circuit 16 is connected to the gate of the thyristor 13. The gate circuit 16 outputs a gate trigger when the voltage across the exciter coil 8, that is, the exciter voltage becomes a predetermined gate trigger voltage. The gate trigger causes the thyristor 13 to conduct, and the primary voltage is applied to the primary coil T1 of the ignition coil 12 by the charge stored in the capacitor 17. The secondary coil T2 of the ignition coil 12 is connected to an engine spark plug 18. A high voltage corresponding to the winding ratio is induced in the secondary coil T2 by the current flowing through the primary coil T1.

  FIG. 4 is a timing chart showing the operation of the ignition circuit. The operation of the ignition circuit will be described with reference to FIG. When the crankshaft 2 is rotated in a direction indicated by an arrow R in FIGS. 1 and 2 using known engine start operation means such as a starter motor or a start rope, the rotor 1 also rotates integrally.

  As the rotor 1 rotates, the inductor 11 approaches and separates from the iron core 4. Along with this, the direction and the number of magnetic fluxes in the iron core 4 change. First, as the tip of the inductor 11 in the rotational direction passes through the magnetic pole 5 and approaches the magnetic pole 6, the magnetic flux Φ1 in the magnetic pole 6 around which the exciter coil 8 is wound increases as shown in FIG. Then, when the rear end of the inductor 11 in the rotational direction moves away from the magnetic pole 6, the magnetic flux Φ1 decreases. On the contrary, since the tip of the inductor 11 approaches the magnetic pole 7, the magnetic flux Φ2 starts to increase. Then, as the rear end of the inductor in the rotational direction moves away from the magnetic pole 7, the magnetic flux φ2 decreases.

  In response to the change in the number of magnetic fluxes Φ1 and Φ2 and the direction of the magnetic flux, a counter electromotive voltage, that is, an exciter voltage V is generated in the exciter coil 8, and the exciter voltage V is as shown in FIG. It changes according to the changing speed of the number of magnetic fluxes. If the number of magnetic fluxes suddenly increases or decreases, the induced voltage is large. The capacitor 17 is charged by the positive side voltage V1 of the exciter voltage V. The gate trigger voltage of the gate circuit 16 is set to a negative voltage value Vg, and when the exciter voltage V becomes lower than the negative voltage value Vg, the gate circuit 16 triggers the gate trigger on the thyristor 13.

  FIG. 4C is a diagram showing a change in voltage of the capacitor 17. The capacitor 17 starts to be charged when the exciter voltage V turns to the positive side. When the exciter voltage V becomes lower than the negative voltage value Vg, the thyristor 13 is turned on, so that the accumulated charge of the capacitor 17 is released to the primary coil T1 of the ignition coil 12, and the voltage Vc of the capacitor 17 decreases ( Virtually zero).

  The ignition phase can be easily adjusted by changing the gate trigger voltage Vg or delaying the trigger signal in the gate trigger circuit 16.

  FIG. 4D is a diagram showing the secondary side voltage of the ignition coil 12. Due to the discharge of the capacitor 17, a current suddenly flows into the primary coil T1 of the ignition coil 12, and due to this current, the secondary coil T2 of the ignition coil 12 has a high secondary voltage as shown in FIG. V2 is induced. The secondary voltage V2 causes a discharge between the electrodes of the spark plug 18 to ignite the engine. By this discharge, energy in the secondary coil T2 of the ignition coil 12 is released, and the secondary voltage V2 decreases.

  The positions of the rotor 1, the inductor 11, and the iron core 4, and the gate trigger voltage are set so that the discharge of the capacitor 17 to the primary coil T1 of the ignition coil 12 is at a time suitable for engine ignition. .

  Next, a second embodiment of the present invention will be described. FIG. 5 is a front view showing the main configuration of the ignition device according to the second embodiment, FIG. 6 is a circuit diagram of the ignition device according to the second embodiment, and FIG. 7 is a timing chart. 5 to 7, the same reference numerals as those in FIGS. 1 to 4 denote the same or equivalent parts. In FIG. 5, the rotor 1 is provided with four inductors 11. Note that the number of inductors is not limited to four and may be plural.

  In FIG. 6, the gate circuit 15 is configured to output a gate trigger (discharge trigger) to the thyristor 13 by an external signal. In this example, a trigger coil 21 is disposed opposite to an inductor 20 provided on a cam shaft 19 of an engine synchronized with the rotor 1, and an external signal is input from the trigger coil 21 to the gate circuit 16 every rotation of the rotor 1. I am letting. The external signal is not limited to this, and the external signal can be generated at a position suitable for ignition set in advance with respect to the rotational position of the engine by electronic control.

  FIG. 7A shows changes in the magnetic fluxes Φ1 and Φ2 in the iron core 4 that occur during one rotation of the rotor 1. Magnetic fluxes Φ1 and Φ2 are generated four times in different directions during one rotation of the rotor 1 according to the number of inductors 11.

  FIG. 7B shows changes in the exciter voltage V due to the magnetic fluxes Φ1 and Φ2. The exciter voltage V generated by the magnetic fluxes Φ1 and Φ2 includes four positive voltages V1 that can charge the capacitor 17 during one rotation of the rotor.

  FIG. 7C shows the voltage change of the capacitor 17, and FIG. 7D shows the generation timing of the gate trigger. FIG. 7E shows the voltage of the secondary coil T2 of the ignition coil 12. Unlike the first embodiment, in the second embodiment, the gate trigger of the thyristor 13 is set to be generated only once per rotation of the rotor 1 (see FIG. 7 (d)). Each time the positive voltage V1 is generated, the capacitor 17 is charged with the voltage V1.

  Then, the potential of the capacitor 17 is increased by stacking a plurality of times (four times), and when the gate trigger is supplied at the timing shown in FIG. It is output to the primary side coil T1. This discharge voltage is higher than when a single inductor 11 is used due to charge accumulation. This high discharge voltage is output to the primary coil T1 of the ignition coil 12, and a large ignition energy is applied to the spark plug 18. Thus, by increasing the number of inductors 11, it is possible to meet the demand for large ignition energy.

  The ignition coil 12 may be wound around an iron core provided separately from the iron core 4 around which the exciter coil 7 is wound, or may be wound around the iron core 4 common to the exciter coil 8.

  FIG. 8 is a front view of an exciter in which the ignition coil 12 is wound around the magnetic pole of the iron core 4 common to the exciter coil 8. In FIG. 8, the exciter coil 8 is wound near the base of the magnetic pole 6, and the ignition coil 12 is wound on the tip side of the magnetic pole 6 adjacent to the exciter coil 8. In the ignition coil 12, a primary coil T1 is wound around the magnetic pole 6, and a secondary coil T2 is disposed on the outer peripheral side via an insulating bobbin 22.

  FIG. 9 is a front view of an exciter showing an example in which the installation position of the permanent magnet 10 is modified. In FIG. 9, the permanent magnets 10 and 9 are not embedded in the magnetic poles 5 and 7 but are attached to the tip surfaces of the magnetic poles 5 and 7.

  FIG. 10 is a front view showing an example of an exciter in which the iron core 4 is deformed. In FIG. 10, the iron core 4 includes two magnetic poles 5 and 6, and a permanent magnet 10 is embedded in the magnetic pole 5 and the magnetic pole 6 around which the exciter coil 8 is wound.

  The iron core 4 is not limited to those shown in FIGS. 8 to 10 and can be variously modified by arbitrarily combining them. For example, in the case shown in FIGS. 9 and 10, the ignition coil 12 can be deformed so as to be wound around a common magnetic pole with the exciter coil 8 as shown in FIG. You may attach a position to the front end surface of a magnetic pole.

  The inductor 11 is not limited to the magnetic plate attached to the rotor 1 but can be formed integrally with the rotor 1. For example, the rotor 1 can be formed of cast iron, and the inductor 11 can be cast integrally with the rotor 1, or the rotor 1 can be formed of a laminated steel plate, which corresponds to the inductor 11 when punching the steel plate. You may punch a steel plate in the shape which has a protruding part. And this rotor 1 can also be laminated | stacked and the rotor 1 which has the inductor 11 integrally can also be formed. Further, the portion corresponding to the inductor 11 can be extruded by a mold by molding the bowl-shaped rotor 1 by drawing.

  When the rotor 1 is formed of a nonmagnetic material such as aluminum, the inductor 11 does not need to protrude from the outer peripheral surface of the rotor 1 and may be embedded in the outer peripheral surface of the rotor 1 by insert molding.

  Note that the outer peripheral surface of the rotor 1 may be recessed over a length corresponding to the above-described inductor. In this case, a change in magnetic flux is obtained at both ends of the recessed portion, so that the same effect as that provided by the inductor 11 can be obtained.

It is a front view (the 1) of an ignition device concerning one embodiment of the present invention. It is a front view (the 2) of the ignition device concerning one embodiment of the present invention. It is a figure which shows the ignition circuit of the ignition device which concerns on one Embodiment of this invention. It is a timing chart of ignition operation. It is a front view of the ignition device which concerns on 2nd Embodiment of this invention. It is a figure which shows the ignition circuit of the ignition device which concerns on 2nd Embodiment of this invention. It is a timing chart of the ignition operation according to the second embodiment. FIG. 3 is a front view of an exciter in which an ignition coil and an exciter coil are wound around a common iron core. It is a front view of the exciter which shows the example which changed the installation position of the permanent magnet. It is a front view which shows the example of the exciter which deform | transformed the iron core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Crankshaft, 3 ... Exciter, 4 ... Iron core, 5, 6, 7 ... Magnetic pole, 8 ... Exciter coil, 10 ... Permanent magnet, 11 ... Inductor, 12 ... Ignition coil, 16 ... Gate circuit, 17 ... capacitor, 18 ... spark plug, 19 ... camshaft, 21 ... trigger circuit

Claims (3)

An iron core disposed at a position facing the outer peripheral surface of the rotor that rotates in synchronization with the rotation of the engine, and an exciter coil wound around the iron core;
In an ignition device for an engine that performs an ignition operation with generated energy induced in the exciter coil at an ignition timing synchronized with the rotation of the engine,
A permanent magnet incorporated in the iron core;
An inductor provided in the rotor and forming a closed magnetic path of magnetic flux generated by the permanent magnet;
A capacitor charged with generated energy induced in the exciter coil when the inductor passes through the opposite portion of the iron core with the rotation of the rotor, and the capacitor is discharged at the ignition timing to ignite An ignition device for an engine, comprising: an ignition circuit configured to operate.   The engine ignition device according to claim 1, wherein the inductor is provided at a plurality of locations on an outer peripheral surface of the rotor. 3. The engine ignition device according to claim 2, further comprising trigger forming means for inputting a discharge trigger of the capacitor as an external signal to the ignition circuit.

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