JP3575267B2 - Ignition device for internal combustion engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a current interruption type ignition device for an internal combustion engine that generates a high voltage for ignition by controlling a current flowing through an ignition power supply coil by a transistor.
[0002]
[Prior art]
As an ignition device for an internal combustion engine, a transistor-controlled current interruption type for generating a high voltage for ignition by further increasing a voltage induced in the ignition power supply coil by interrupting a current flowing through the ignition power supply coil Ignition devices are known.
[0003]
Such an ignition device for an internal combustion engine is disclosed in JP-A-52-87538, JP-A-54-49428, and JP-A-61-31668 issued by the Japan Patent Office.
[0004]
A conventional transistor-controlled current interruption type ignition device includes an ignition power supply coil provided in a magnet generator mounted on an engine and inducing an AC voltage in synchronization with rotation of the engine, and collectors at both ends of the ignition power supply coil. An emitter-to-emitter circuit is connected in parallel, and when a voltage of one half cycle is induced in the ignition power supply coil, a base current is applied by the induced voltage and the current control transistor is turned on. When the voltage between the collector and the emitter of the transistor reaches a predetermined level (when the current flowing through the ignition power supply coil reaches a predetermined cutoff value), the transistor is turned on and the base current of the current control transistor is bypassed from the transistor. A transistor control switch for turning on and a voltage induced in the ignition power supply coil when the current control transistor is turned off to boost the ignition It is constituted by a booster means for generating a pressure.
[0005]
In an internal combustion engine equipped with this type of ignition device, when the engine is started, an AC voltage is induced in an ignition power supply coil provided in the magnet generator. When a voltage of one half cycle is induced in the ignition power supply coil, a base current is applied to the current control transistor, so that the transistor becomes conductive, and a short-circuit current flows between the collector and the emitter of the current control transistor from the ignition power supply coil. Flows. When it is detected that the current flowing through the ignition power supply coil has reached a predetermined cutoff value and the voltage across the ignition power supply coil has reached a set value, the transistor control switch is turned on to turn on the base of the current control transistor. Since the current is bypassed from the transistor, the current control transistor is turned off. As a result, the current flowing through the ignition power supply coil is interrupted, so that a voltage having a high polarity is induced in the ignition power supply coil so as to continue to flow the current that has been flowing. The induced voltage is boosted to a high voltage for ignition by a boosting means, and the high voltage for ignition is applied to a spark plug attached to a cylinder of the internal combustion engine. The engine is ignited by spark discharge generated in the spark plug when the high voltage for ignition is applied.
[0006]
The cut-off value of the current supplied to the ignition power supply coil (the magnitude of the current flowing through the ignition power supply coil when the transistor is turned off) must be greater than the value required to obtain the ignition high voltage having a predetermined peak value. Is set.
[0007]
With this configuration, it is not necessary to separately provide a signal source for generating a signal for determining the ignition position, so that the configuration of the ignition device for an internal combustion engine can be simplified.
[0008]
[Problems to be solved by the invention]
As is well known, in an internal combustion engine, the ignition position (the rotation angle position of the crankshaft when the ignition is performed) at the time of starting the engine and the low-speed rotation is changed to the rotation angle position (hereinafter referred to as the rotation angle position at the time when the piston reaches the top dead center). (It is simply referred to as top dead center). At high speed, the ignition position needs to be a position advanced from top dead center. However, in the above-described transistor-controlled ignition device, the rotation angle position of the crankshaft when the current flowing through the ignition power supply coil reaches the cutoff value becomes almost constant, so that the ignition position changes with the change in the engine speed. Was slight. Therefore, in this type of conventional ignition device, the ignition position is almost constant both at low speed and high speed of the engine, and it is difficult to set the ignition position so that the engine operates satisfactorily from low speed to high speed. there were.
[0009]
Further, in the conventional current cutoff type ignition device for an internal combustion engine, since a high voltage is generated only once at the time of ignition, if the ignition of the fuel fails for any reason, there is a problem that unburned gas is discharged from the engine. there were.
[0010]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a transistor-controlled ignition device for an internal combustion engine in which the range of change in the ignition position in accordance with the change in the rotation speed of the internal combustion engine can be made wider than before.
[0011]
Another object of the present invention is to provide an internal combustion engine in which a high voltage for ignition is generated a plurality of times when an ignition operation is performed to reduce the probability of a fuel ignition error occurring and prevent the emission of unburned gas. It is to provide an ignition device.
[0012]
[Means for Solving the Problems]
INDUSTRIAL APPLICABILITY The present invention is applied to a current cutoff type ignition device for an internal combustion engine that obtains a high voltage for ignition by boosting a voltage induced by interrupting a current flowing through an ignition power supply coil.
[0013]
An ignition device according to the present invention is provided in a magnet generator driven by an internal combustion engine, and generates an AC voltage of at least one cycle while the internal combustion engine makes one rotation in a positive direction. When a voltage of a half cycle of one polarity which appears first among positive and negative half cycles of the AC voltage induced by the ignition power coil during one rotation of the engine in the positive direction is generated, a base current is generated from the ignition power coil side. A first current control transistor that is applied and conducts to substantially short-circuit the ignition power supply coil; and a voltage across the ignition power supply coil when the first current control transistor is on is predetermined. And a first transistor control circuit for performing a control operation of turning off the first current control transistor when the first current control transistor is reached. A first current control circuit for inducing a high voltage in the ignition power supply coil; and a base current being supplied from the ignition power supply coil side when the ignition power supply coil induces a half-cycle voltage of the other polarity to conduct the ignition. A second current control transistor that substantially short-circuits the power supply coil; and a voltage when the voltage across the ignition power supply coil reaches a predetermined level or reaches a peak when the second current control transistor is conductive. A second transistor control circuit for performing a control operation of turning off the second current control transistor when the second current control transistor is turned off, and generating a high voltage in the ignition power supply coil by turning off the second current control transistor. And the voltage induced in the ignition power supply coil when the first current control transistor or the second current control transistor is turned off. It constituted by providing a step-up means for generating a high voltage for ignition Te.
[0014]
In the present invention, the first transistor control circuit prevents the first transistor control circuit from performing a control operation for turning off the first current control transistor when the rotation speed of the internal combustion engine is equal to or lower than a set value. Is set.
[0015]
In the above-described ignition device, when a voltage of one polarity half cycle is induced in the ignition power supply coil, the first current control transistor is turned on to cause a short-circuit current to flow to the ignition power supply coil. When the voltage across the power supply coil reaches a predetermined value, the first transistor control circuit turns off the first current control transistor to generate a high ignition voltage.
[0016]
When a half cycle voltage of the other polarity is induced in the ignition power supply coil, the second current control transistor is turned on to cause a short-circuit current to flow through the ignition power supply coil. The second transistor control circuit cuts off the second current control transistor when the signal reaches a predetermined value or reaches a peak, and generates a high ignition voltage.
[0017]
In the above-described ignition device, the operation sensitivity of the control circuit is set so that the first transistor control circuit does not perform the control operation when the rotation speed of the engine is equal to or less than the set value. When the ignition power supply coil is at or below the set value, the ignition operation is not performed even if the ignition power supply coil induces a half-cycle voltage of one polarity, and the ignition operation is performed only when the ignition power supply coil generates a half-cycle voltage of the other polarity. Is
[0018]
When the rotation speed of the internal combustion engine exceeds a set value, the first transistor control circuit starts to perform a control operation, so that the ignition power supply coil has one polarity prior to inducing a half-cycle voltage of the other polarity. When the half cycle voltage is induced, the ignition operation is performed.
[0019]
In the rotation region where the rotation speed of the internal combustion engine exceeds the set value, the ignition operation is also performed when the ignition power supply coil generates a half-cycle voltage of one polarity and then generates a half-cycle voltage of the other polarity. When the half cycle voltage of the other polarity is generated after the half cycle voltage of the other polarity is generated, the ignition operation is also performed by the half cycle voltage of the one polarity.
[0020]
As described above, in the ignition device of the present invention, in the rotation region where the rotation speed of the engine is equal to or lower than the set value, the ignition operation is performed only when the ignition power supply coil generates the voltage of the other polarity half cycle, and the rotation of the engine is performed. In the rotation region where the speed exceeds the set value, the ignition operation is performed when the ignition power supply coil induces a half-cycle voltage of one polarity prior to inducing a half-cycle voltage of the other polarity. The ignition position is set to a position near top dead center in the low-speed region where the rotation speed is equal to or lower than the set value, and the ignition position is advanced to a position sufficiently advanced from the top dead center in the region where the engine rotation speed exceeds the set value. be able to. Therefore, the ignition position can be set so that the engine operates satisfactorily at both low and high speeds of the engine.
[0021]
Further, in the ignition device of the present invention, since the ignition spark can be generated a plurality of times in a region where the rotation speed of the engine exceeds the set value, the probability of failing to ignite the fuel is reduced and the emission of unburned gas is prevented. can do.
[0022]
In the present invention, the first transistor control circuit is configured to prevent the first transistor control circuit from performing a control operation of turning off the first current control transistor when the rotation speed of the internal combustion engine is equal to or lower than the set value. In order to facilitate the setting, a current for limiting the current flowing from the ignition power supply coil to the first current control circuit side is provided between the ignition power supply coil and the first current control circuit. A limiting element may be inserted.
[0023]
Usually, an ignition coil is used as the booster. In a current interruption type ignition device, an ignition coil is provided in a magnet generator and an AC voltage is induced in a primary coil of the ignition coil so that the primary coil of the ignition coil also serves as an ignition power source. In some cases, the ignition coil is provided outside the magnet generator, and the power generation coil provided in the magnet generator is used as the ignition power supply coil. The present invention is applied to both of these cases. be able to.
[0024]
The magnet generator used in the ignition device according to the present invention is, for example, a flywheel made of a ferromagnetic material and attached to a crankshaft of an internal combustion engine and fixed in a recess formed in a part of an outer periphery of the flywheel. A magnet rotation having one permanent magnet magnetized radially of the flywheel and having a three-pole magnet field formed by the permanent magnet and the outer periphery of the flywheel on both sides of the recess. And an armature formed by winding the ignition power supply coil around an iron core having a magnetic pole portion facing the magnetic pole of the magnet rotor. And a half-cycle voltage of the other polarity and a half-cycle voltage of one polarity appear in order to induce an AC voltage of one and a half cycles.
[0025]
In this case, the peak position of the voltage in the first half cycle of the AC voltage induced in the ignition power supply coil and the peak position of the induced voltage in the second half cycle during the rotation of the internal combustion engine during one rotation of the internal combustion engine, respectively, The ignition position coincides with the ignition position immediately after the speed exceeds the set value and the ignition position when the rotational speed of the engine is lower than the set value, and is induced in the ignition power supply coil while the internal combustion engine makes one rotation in the forward direction. The distance between the magnetic poles of the magnet field of the magnet rotor and the magnet rotor and the armature are set so that the peak position of the voltage in the last half cycle of the AC voltage falls within the rotation angle range of the engine in which ignition spark is allowed to occur. Is set.
[0026]
When the magnet generator is configured as described above, an ignition coil that forms the booster may be wound around an armature coil, and the primary coil of the ignition coil may form an ignition power supply coil.
[0027]
To prevent a high reverse voltage from being applied to the other current control circuit when one of the first current control circuit and the second current control circuit performs an operation of interrupting the current supplied to the ignition power supply coil. When the voltage of one half cycle of one polarity, which appears first among the positive and negative half cycles of the AC voltage induced by the ignition power supply coil while the internal combustion engine makes one rotation in the positive direction, becomes the terminal on the high potential side when the voltage is induced. By providing first and second diodes each having an anode and a cathode connected to one end of the ignition power supply coil, and interposing these diodes between the first and second current control circuits and the ignition power supply coil, Preferably, the first current control circuit and the second current control circuit are electrically separated.
[0028]
Further, when one of the first current control circuit and the second current control circuit performs an operation of interrupting the current supplied to the ignition power supply coil, a high reverse voltage is prevented from being applied to the other current control circuit. Therefore, when a voltage of a half cycle of one polarity which appears first among positive and negative half cycles of the AC voltage induced by the ignition power supply coil while the internal combustion engine makes one rotation in the positive direction is induced, the terminal on the low potential side is generated. A first and a second diode having a cathode and an anode respectively connected to one end of the ignition power coil, and these diodes are interposed between the first and second current control circuits and the ignition power coil. By doing so, the first current control circuit and the second current control circuit may be electrically separated.
[0029]
The first transistor control circuit is, for example, a first current control circuit provided so as to conduct when a drive signal is supplied and to bypass a base current of the first current control transistor from the transistor. A drive signal is supplied to the base current bypass switch for the first current control circuit when the voltage between both ends of the ignition power supply coil when the first current control transistor is conducting and the first current control transistor reaches a predetermined level. And a first current control circuit bypass switch driving circuit that provides the following.
[0030]
The second transistor control circuit is turned on when a drive signal is supplied, and the second current control circuit base current is provided so as to bypass the base current of the second current control transistor from the transistor. A bypass switch and a base current bypass switch for a second current control circuit when it is detected that the voltage across the ignition power supply coil has reached a predetermined level when the second current control transistor is conducting. And a second control circuit bypass switch drive circuit that supplies a drive signal to the second control circuit.
[0031]
The second transistor control circuit is further provided with a second current control circuit base provided so as to conduct when a drive signal is supplied and to bypass the base current of the second current control transistor from the transistor. A drive signal is provided to the current bypass switch and the second current control circuit base current bypass switch when the voltage across the ignition power supply reaches a peak when the second current control transistor is conducting. It can also be constituted by a peak detection circuit.
[0032]
Further, the second transistor control circuit includes a second control circuit base current side provided so as to conduct when a drive signal is supplied and to bypass a base current of the second current control transistor from the transistor. Detection circuit for providing a drive signal to a second switch and a base current bypass switch for a second control circuit when a voltage across the ignition power supply coil reaches a peak when the second current control transistor is conducting. And a second current for supplying a drive signal to the second control circuit base current bypass switch when the voltage across the ignition power supply reaches a set level when the second current control transistor is conducting. It can also be constituted by a control circuit bypass switch drive circuit. In this case, the set level is a voltage peak generated at both ends of the ignition power supply coil through which a current flows due to conduction of the second current control transistor when the rotation speed of the internal combustion engine reaches the set cutoff value switching speed. Set it almost equal to the value.
[0033]
When the second transistor control circuit is configured as described above, the second current control transistor is conductive when the internal combustion engine is rotating at a rotation speed lower than the set cutoff value switching speed. When the voltage at both ends of the ignition power supply coil reaches a peak, the second current control transistor is turned off, and when the internal combustion engine is rotating at a rotation speed higher than the cutoff value switching speed, both ends of the ignition power supply coil are turned off. When the voltage of the second transistor reaches a certain level, the second current control transistor is turned off.
[0034]
When the second transistor control circuit is configured as described above, when the engine speed is low, the ignition position is set to the peak position of the induced voltage of the other polarity half cycle of the ignition power supply coil, and the ignition position is set to the top dead center. You can delay to a nearby position. Further, when the rotation speed of the engine becomes equal to or higher than the set cutoff value switching speed, the cutoff value of the current can be switched to a low value, so that the current flowing through the second current control transistor becomes excessive and Destruction can be prevented.
[0035]
The first current control transistor and the second current control transistor may be each composed of a single transistor, or may be composed of a Darlington-connected composite transistor.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show an example of the configuration of an ignition device for an internal combustion engine according to the present invention. In these figures, 1 is an ignition coil having a primary coil W1 and a secondary coil W2, 2 and 3 are first and second diodes, respectively, 4 and 5 are first and second current control circuits, respectively, 6 Is a spark plug attached to the cylinder of the engine. In this example, the ignition coil 1 is provided in a magnet generator 7 driven by an internal combustion engine, and the primary coil W1 of the ignition coil 1 also serves as an ignition power supply coil.
[0037]
As shown in FIG. 2, the magnet generator 7 includes a magnet rotor 9 attached to a rotating shaft 8 of the engine, and a stator 10 fixed to a case or a cover of the engine. The ignition coil 1 is provided on the side 10.
[0038]
In the present invention, a magnet rotor 9 having a magnet field only in a part of its circumferential direction is used, and an ignition power supply coil is provided near a rotation angle region where an ignition operation is performed during one rotation of the engine. Generates an AC voltage of at least one cycle.
[0039]
The illustrated magnet rotor 9 is fixed to the center of a flywheel 13 attached to the crankshaft 8 of the internal combustion engine in a concave portion 13a formed in a part of the outer periphery of the flywheel, and is fixed in the radial direction of the flywheel. It comprises a magnetized permanent magnet 14 and a pole piece 15 abutting on a magnetic pole surface outside the permanent magnet 14. In the illustrated example, the magnet 14 is magnetized in the radial direction of the rotor so that the magnetic pole outside the permanent magnet 14 becomes the N pole, and the S pole of the magnet 14 is formed on the outer peripheral surface on both sides of the concave portion 13 a of the flywheel 13. Respectively, to form a magnet field of three poles in total.
[0040]
The ignition coil 1 is composed of a primary coil W1 and a secondary coil W2 wound around a U-shaped iron core 1a having two magnetic pole portions 1a1 and 1a2 facing magnetic poles of a magnetic field of a magnet rotor 9.
[0041]
The angular interval between the magnetic pole portions 1a1 and 1a2 of the iron core 1a of the ignition coil 1 is set substantially equal to the angular interval between the center of the N pole of the magnet field and the centers of the S poles on both sides thereof. One cycle and half cycle of AC voltage is induced in the primary coil W1 of the ignition coil by a change in magnetic flux of one cycle generated in the iron core 1a when the magnetic pole of the child 9 passes the position of the magnetic pole parts 1a1 and 1a2 of the iron core 1a. It has become.
[0042]
FIG. 3A shows the waveform of the AC voltage induced in the primary coil (ignition power supply coil) of the ignition coil during one rotation of the internal combustion engine with respect to the rotation angle θ of the crankshaft of the engine. The induced voltage includes a half cycle voltage Vp1 of one polarity having a relatively low peak value, a voltage Vn of a half cycle of the other polarity having a high peak value, and a half voltage of one polarity having a relatively low peak value. It becomes an AC voltage for one and a half cycles consisting of the cycle voltage Vp2.
[0043]
Although the polarity of the half cycle of the AC voltage induced in the ignition power coil is relative, in the present invention, of the half cycles sequentially appearing in the AC voltage induced in the ignition power coil, the ignition power coil is wound. The first half cycle generated when the magnetic pole of the rotor starts to oppose the magnetic pole portion of the iron core and the half cycle of the same polarity as the first half cycle are defined as half cycles of one polarity, and the one polarity of the first half is used. A half cycle that follows the half cycle of the above is defined as a half cycle of the other polarity.
[0044]
In the illustrated example, one end of a primary coil W1 of the ignition coil 1 and one end of a secondary coil W2 are commonly connected, and the other end of the primary coil W1 is grounded. The other end of the secondary coil W2 of the ignition coil is connected to a non-ground side terminal of an ignition plug 6 attached to a cylinder of the engine through a high-voltage cord.
[0045]
The anode of the first diode 2 and the cathode of the second diode 3 are connected to one end of the primary coil W1 of the ignition coil, and are connected between the anode of the first diode 2 and the ground and between the second diode 3 and the ground. Are connected to a first current control circuit 4 and a second current control circuit 5, respectively.
[0046]
More specifically, the first current control circuit 4 includes a first current control transistor TR1 and resistors R1 and R2 for providing a base current to the first current control transistor TR1 from the ignition power supply coil W1 side. A first transistor control circuit for performing a control operation of shutting off the transistor TR1 when the voltage across the ignition power supply coil W1 reaches a predetermined level when the first current control transistor TR1 is conducting. 4a.
[0047]
The first current control transistor TR1 is an NPN transistor, the collector of which is connected to the cathode of the first diode 2, and the emitter of which is grounded. One end of a resistor R1 is connected to the collector of the transistor TR1, and a resistor R2 is connected between the other end of the resistor R1 and the base of the transistor TR1. Therefore, when the ignition power supply coil W1 generates the half-cycle voltages Vp1 and Vp2 of one polarity, the transistor TR1 is supplied with a base current through the diode 2 and the resistors R1 and R2 to conduct.
[0048]
The first transistor control circuit 4a includes a series circuit of resistors R3 and R4 connected between the collector and the emitter of the transistor TR1, an emitter grounded, a collector connected to a connection point of the resistors R1 and R2, and a base connected to a resistor. And an NPN transistor TR2 connected to the connection point of R3 and R4.
[0049]
In this example, the transistor TR2 forms a first control circuit base current bypass switch that conducts when a drive signal is supplied and that bypasses the base current of the first current control transistor TR1 from the transistor TR1. The base current bypass switch for the first current control circuit is provided by the resistors R3 and R4 when the voltage across the ignition power supply coil W1 reaches a predetermined level when the first current control transistor TR1 is conducting. A first current control circuit side-path switch drive circuit that supplies a drive signal to (TR2) is configured.
[0050]
The second current control circuit 5 is configured such that the second current control transistor TR3, the resistors R5 and R6 for providing a base current to the transistor TR3 from the ignition power supply coil W1 side, and the second current control transistor TR3 conduct. A second transistor control circuit 5a that performs a control operation to turn off the second current control transistor TR3 when the voltage across the ignition power supply coil W1 reaches a predetermined level or reaches a peak when It consists of
[0051]
The second current controlling transistor TR3 is formed of an NPN transistor whose collector is grounded, and its emitter is connected to the anode of the second diode 3. The collector of the transistor TR3 is connected to one end of the resistor R5, and the resistor R6 is connected between the other end of the resistor R5 and the base of the transistor.
[0052]
Therefore, the second current control transistor TR3 conducts when a base current is applied through the resistors R5 and R6 when the half-cycle voltage Vn of the other polarity is induced in the ignition power supply coil W1.
[0053]
The second transistor control circuit 5a has an NPN transistor TR4 having a collector connected to a connection point of the resistors R6 and R5, an emitter commonly connected to the emitter of the transistor TR3, a base grounded through the resistor R7, and a collector connected to the collector. An NPN transistor TR5 connected to the base of the transistor TR4, a collector connected to the emitter of the transistor TR5 through a resistor R8, and an emitter commonly connected to the emitter of the transistor TR4; and an anode between the base and the emitter of the transistor TR6. Is connected between the collector of the transistor TR5 and the emitter of the transistor TR4, with the anode connected to the emitter of the transistor TR4. A diode D2, a PNP transistor TR7 having a collector connected to the base of the transistor TR4 and a base connected to the collector of the transistor TR4 through a resistor R9, a resistor R10 connected between the emitter of the transistor TR7 and the ground, and a transistor TR7. And a series circuit of a resistor R11 and a capacitor C1 connected between the emitter of the transistor TR6 and the base of the transistor TR6.
[0054]
In this example, the transistor TR4 constitutes a second current control circuit base current bypass switch that conducts when a drive signal is supplied and that bypasses the base current of the second current control transistor TR3 from the transistor. Have been.
[0055]
The transistors TR5 and TR6, the resistors R7, R8 and R11, the capacitor C1 and the diodes D1 and D2 allow the voltage across the ignition power supply W1 when the second current control transistor TR3 is conducting. A peak detection circuit is provided which provides a drive signal to the second current control circuit base current bypass switch (TR4) when the peak is reached.
[0056]
Further, when it is detected by the transistor TR7 and the resistors R9 and R10 that the voltage across the ignition power supply coil reaches a predetermined level when the second current control transistor is conducting, the second current control is performed. A second control circuit side switch drive circuit that supplies a drive signal to the circuit base current side switch (TR4) is configured.
[0057]
In the ignition device shown in FIG. 1, when the ignition power supply coil W1 generates half-cycle voltages Vp1 and Vp2 of one polarity, a base current is applied to the first current control transistor TR1 through the resistors R1 and R2. The transistor TR1 conducts. As a result, the ignition power supply coil W1 is substantially short-circuited, and a short-circuit current flows from the ignition power supply coil through the diode 2 and the transistor TR1. This short-circuit current increases as the voltage induced in the ignition power supply coil W1 increases. When the short-circuit current reaches a predetermined cutoff value, a predetermined base current (drive signal) is applied to the transistor TR2 through the resistor R3, and the transistor TR2 (the base current bypass switch for the first current control circuit) is turned on. Therefore, the base current flowing through the transistor TR1 is bypassed from the transistor TR1 through the collector and the emitter of the transistor TR2. As a result, the transistor TR1 is turned off, so that the short-circuit current flowing through the ignition power supply coil W1 is cut off, and a high voltage that tends to continue to flow the current that has flowed so far is applied to the ignition power supply coil W1. Induce. This voltage is boosted by the ignition coil 1 constituting the boosting means, and a high voltage for ignition is induced in the secondary coil W2.
[0058]
In the ignition device shown in FIG. 1, the first transistor control circuit 4a does not perform a control operation for turning off the first current control transistor TR1 when the rotation speed of the internal combustion engine is equal to or lower than the set value. The operating sensitivity of the first transistor control circuit 4a (the terminal voltage of W1 of the ignition power supply coil when the transistor TR2 is turned on) is set. This operation sensitivity can be achieved by appropriately adjusting the voltage dividing ratio of the voltage dividing circuit including the resistors R3 and R4. That is, when the rotation speed of the engine is equal to or lower than the set value, the ignition operation is not performed even if the ignition power supply coil W1 generates a half-cycle voltage of one polarity.
[0059]
Further, in the ignition device shown in FIG. 1, when the ignition power supply coil W1 generates a half-cycle voltage of the other polarity, the ignition power supply coil W1-the resistor R7-the PN junction between the base and the collector of the transistor TR5-the transistor TR4 A base current may flow through the transistor TR4 through the path between the base-emitter circuit, the diode 3 and the ignition power supply coil W1. When the transistor TR7 is conducting, a base current can flow through the transistor TR4 also on the path of the ignition power supply coil W1, the resistor R10, the emitter-collector of the transistor TR7, the base-emitter of the transistor TR4, the diode 3, and the ignition power supply coil W1. . However, when the ignition power supply coil W1 generates a voltage of a half cycle of the other polarity, the charging current of the capacitor C1 first flows from the ignition power supply coil W1 through the resistors R10 and R11, the capacitor C1, and the base emitter of the transistor TR6. Since a predetermined base current is applied to the transistor TR6 while the charging current is flowing, the transistor TR6 conducts. While the transistor TR6 is conducting (while the charging current of the capacitor C1 is flowing), almost all the current flowing from the ignition power supply coil W1 through the resistor R7, the PN junction between the base and the emitter of the transistor TR5, the resistor R8, the transistor TR6, Therefore, no base current is applied to the transistor TR4 from the ignition power supply coil W1 through the resistor R7 and the PN junction between the base and collector of the transistor TR5. When the ignition power supply coil W1 generates a half-cycle voltage of the other polarity, a sufficient base current does not flow through the transistor TR7 at the beginning, so that the transistor TR7 is also in a cut-off state. Not even given. As described above, since the transistor TR4 is initially in the cut-off state when the ignition power supply coil W1 generates the voltage Vn of the other polarity half cycle, the base current is supplied from the ignition power supply coil W1 to the transistor TR3 through the resistors R5 and R6. As a result, the transistor TR3 conducts, and a short-circuit current flows from the ignition power supply coil W1 through the transistor TR3.
[0060]
When the short-circuit current flowing through the ignition power supply coil reaches a peak and the voltage across the ignition power supply coil W1 (the voltage between the collector and the emitter of the transistor TR3) reaches a peak, the charging of the capacitor C1 is stopped. The flow stops and the transistor TR6 is turned off. When the transistor TR6 is turned off, a base current flows from the ignition power supply coil W1 to the transistor TR4 through the resistor R7 and the PN junction between the base and collector of the transistor TR5, so that the transistor TR4 is turned on. When the voltage at both ends of the ignition power supply coil W1 reaches a predetermined level, a base current flows from the ignition power supply coil W1 to the transistor TR7 through the resistor R10 and the transistor TR7 conducts, so that the base current flows to the transistor TR4 through the transistor TR7. Flows.
[0061]
That is, in the second current control circuit, when the voltage across the ignition power supply coil W1 reaches a peak or when the voltage across the ignition power supply coil W1 reaches a predetermined value and the transistor TR7 is turned on, the transistor TR4 Becomes conductive. When the transistor TR4 is turned on, the base current of the transistor TR3 is bypassed from the transistor TR3 through the transistor TR4, so that the transistor TR3 is turned off. As a result, the current flowing through the ignition power supply coil W1 is cut off, and a high ignition voltage is induced in the secondary coil W2 of the ignition coil. Therefore, when a half-cycle voltage of the other polarity is induced in the ignition power supply coil, the voltage at both ends of the ignition power supply coil reaches a peak or the voltage across the ignition power supply coil has a predetermined value (the transistor TR7 is turned on). Value) is the ignition position.
[0062]
In the ignition device shown in FIG. 1, when the rotation speed of the internal combustion engine is lower than the set cutoff value switching speed, the transistor TR7 is kept in the cutoff state, and when the rotation speed reaches the cutoff value switching speed, The resistance values of the resistors R9 and R6 for limiting the base current of the transistor TR7 are set so that a predetermined base current flows through the transistor TR7 at a position where the voltage between both ends of the ignition power supply coil W1 reaches a peak, and the transistor TR7 becomes conductive. Have been.
[0063]
Therefore, when the rotation speed of the engine is lower than the cutoff value switching speed, the ignition operation is performed when the voltage across the ignition power supply coil that induces the half-cycle voltage of the other polarity reaches a peak, and the engine operates. When the rotation speed of the ignition power supply coil exceeds the cutoff value switching speed, the ignition operation is performed when the voltage across the ignition power supply coil reaches a predetermined value at a position ahead of the position where the voltage across the ignition power supply coil reaches a peak. Done.
[0064]
3A and 3B show the no-load output voltage waveform of the ignition power supply coil W1 and the output voltage waveform of the secondary coil W2 of the ignition coil when the rotation speed of the engine is equal to or less than the set value. B). FIGS. 4A and 4B show a no-load output voltage waveform of the ignition power supply coil W1 and an output voltage waveform of the secondary coil W2 of the ignition coil when the rotation speed of the engine exceeds the set value, respectively. FIG. 5 (A) shows the no-load output voltage waveform of the ignition power supply coil W1 and the output voltage waveform of the secondary coil W2 of the ignition coil when the rotation speed exceeds the cutoff value switching speed set higher than the set value. ) And (B).
[0065]
The operation of the ignition device shown in FIG. 1 is summarized as follows.
[0066]
In a low-speed region in which the rotation speed of the internal combustion engine is equal to or lower than the set value, when the ignition power supply coil induces a voltage Vp1 of one polarity half cycle, the transistor control circuit 4a of the first current control circuit 4 sets the transistor TR1 3 is set so as not to perform the control operation of turning off the transistor TR7, and the transistor TR7 is set not to conduct when the ignition power supply coil induces the voltage Vn of the other polarity half cycle. As shown in B), during the half cycle of the other polarity of the output of the ignition power supply coil, the current flowing through the ignition power supply coil W1 at the position θ1 at which the voltage across the ignition power supply coil reaches a peak is cut off, The ignition high voltage Vhn is generated in the secondary coil W2 of the coil.
[0067]
When the rotation speed of the engine exceeds the set value, when the voltage across the ignition power supply coil W1 through which the current flows through the transistor TR1 reaches a peak during a half cycle of one polarity of the output of the ignition power supply coil W1. Then, the voltage reaches a predetermined value, and the transistor control circuit 4a of the first current control circuit 4 performs a control operation. Therefore, as shown in FIG. 4B, during the period in which the ignition power supply coil generates the voltage Vp1 of one polarity half cycle, the ignition high voltage is at the position θ2 where the voltage across the ignition power supply coil reaches a peak. Vhp1 occurs.
[0068]
As the rotational speed of the engine further increases beyond the set value, the position where the voltage across the ignition power supply coil reaches a predetermined value during a period in which the ignition power supply coil generates a half-cycle voltage of one polarity. Therefore, the ignition position is advanced in the process of further increasing the rotation speed of the engine beyond the set value. When the rotational speed of the engine increases to some extent, the output thereof decreases due to the armature reaction of the magnet generator, and the ignition position tends to be delayed.
[0069]
Also, even in a region where the rotational speed of the engine exceeds the set value, the current flowing through the ignition power coil W1 at the position θ1 at which the voltage across the ignition power coil reaches a peak during a half cycle of the other polarity of the output of the ignition power coil is obtained. During the period in which the ignition high voltage Vhn is generated in the secondary coil W2 of the ignition coil and then the ignition power supply coil generates the half-cycle voltage Vp2 of one polarity, the voltage at both ends of the ignition power supply coil is reduced. The ignition high voltage Vhp2 is generated at a position θ3 where the voltage reaches a predetermined value.
[0070]
When the rotation speed of the internal combustion engine further rises and exceeds the cutoff value switching speed, as shown in FIG. 5B, the ignition power supply coil W1 generates a half-cycle voltage of the other polarity as shown in FIG. When the voltage at both ends of the coil reaches a predetermined value at a position θ1 ′ which is ahead of the position θ1 at which the peak is reached, the transistor TR3 is turned off, and the ignition high voltage Vhn is generated in the secondary coil W2 of the ignition coil. I do.
[0071]
As described above, in the ignition device of the present invention, in the rotation region where the rotation speed of the engine is equal to or less than the set value, only when the ignition power supply coil W1 generates the voltage Vn of the other polarity half cycle as shown in FIG. In the rotation region where the ignition operation is performed and the rotation speed of the engine exceeds the set value, as shown in FIGS. 4 and 5, the ignition power supply coil induces the half-cycle voltage Vn of the other polarity before being induced. Since the ignition operation is also performed when a half-cycle voltage Vp1 of one polarity is induced, the ignition position is set to a position near top dead center in a low-speed region where the engine speed is equal to or lower than a set value, and the engine speed is reduced. In a region exceeding the set value, the ignition position can be advanced to a position sufficiently advanced from the top dead center. Therefore, the ignition position can be set so that the engine operates satisfactorily at both low and high speeds of the internal combustion engine.
[0072]
Further, in the ignition device of the present invention, since the ignition spark can be generated a plurality of times in a region where the rotation speed of the engine exceeds the set value, the probability of failing to ignite the fuel is reduced and the emission of unburned gas is prevented. can do.
[0073]
FIG. 6 shows an example of the ignition characteristics (the characteristics of the ignition position with respect to the rotation speed N) obtained by the ignition device of FIG. 1. In FIG. 6, TDC indicates the top dead center of the engine, and BTDC indicates the top dead center. It is shown that it is on the more advanced side. A curve a in FIG. 6 shows the characteristic when only the second current control circuit 5 is provided. This characteristic is the same as the ignition characteristic of the conventional current interruption type ignition device. A curve b in FIG. 6 shows the characteristic obtained by the first current control circuit 4. In the case where the first current control circuit 4 and the second current control circuit 5 are provided as in the present invention, The ignition characteristic is as shown by a curve c shown by a broken line in FIG. When only the second current control circuit 5 is provided, the ignition position hardly changes. However, as in the present invention, the output of the ignition power supply coil has a half cycle of one polarity and a half cycle of the other polarity respectively. A first current control circuit and a second current control circuit for performing a control operation for interrupting a current are provided, and a control operation for interrupting the current only to the second current control circuit when the engine speed is equal to or lower than a set value is provided. When the engine speed reaches the set value Ns, the control operation for interrupting the current even in a half cycle of one polarity of the ignition power supply coil is performed in a region where the rotational speed exceeds the set value. A characteristic that the position is advanced in a step-like manner can be obtained.
[0074]
In the ignition device of FIG. 1, when the peak value of the induced voltage in one half cycle of one polarity of the ignition power supply coil is high when the engine is at low speed, the first current control is performed when the rotation speed of the engine is equal to or lower than the set value. There is a possibility that setting to prevent the circuit 4 from interrupting the current may be difficult to perform simply by adjusting the circuit constant of the first current control circuit 4. In that case, as shown in FIG. 7, a current limiting element 20 is inserted between the ignition power supply coil W1 and the first current control circuit 4, and the first current controlling transistor is controlled by the current limiting element. What is necessary is just to limit the magnitude of the short-circuit current flowing through TR1. In the example shown in FIG. 7, a current limiting element 20 is inserted between the first diode 2 and the first current control circuit 4. As the current limiting element 20, for example, as shown in FIG. 8A, a diode D20 in the same direction as the first diode 2 can be used. In this case, if necessary, the current limiting element 20 may be configured by connecting a plurality of diodes D20 in series. As shown in FIG. 8B, a resistor R20 may be used as the current limiting element 20. Although not shown in FIG. 8, a resistor and a diode connected in series are used as the current limiting element 20. You may.
[0075]
In the above example, when the rotation speed of the engine becomes equal to or higher than the set cutoff value switching speed, the ignition position during the period in which the ignition power supply coil generates a half-cycle voltage of the other polarity is determined by the ignition power supply coil. The terminal voltage is advanced from a position where the terminal voltage reaches a peak to a position where the terminal voltage reaches a set level lower than the peak value. With this configuration, it is possible to prevent an excessive cutoff value of the current cut off by the transistor TR3 when the rotation speed of the engine increases, so that an inexpensive transistor TR3 having a relatively small current capacity is used. be able to. However, the present invention is not limited to the case where the second current control circuit 5 is configured in this manner. In a region where the rotational speed of the engine exceeds a set value, the ignition power supply coil is used for a half cycle of the other polarity. The ignition position during the voltage generation period may always be the position where the terminal voltage of the ignition power supply coil reaches a peak.
[0076]
If the ignition position during the period in which the ignition power supply coil generates the half-cycle voltage Vn of the other polarity is always the position at which the terminal voltage of the ignition power supply coil reaches a peak, in the circuit shown in FIG. The resistor R9 may be omitted.
[0077]
Also, instead of always setting the ignition position during the period in which the ignition power coil generates a half-cycle voltage of the other polarity to the position where the terminal voltage of the ignition power coil reaches a peak, the terminal voltage of the ignition power coil reaches a constant value. It can also be a position. In this case, the voltage at both ends of the ignition power supply coil is detected by the resistance voltage dividing circuit, similarly to the first current control circuit 4, without providing the peak detection circuit in the second current control circuit 5. The second current control circuit 5 may be configured to turn on the transistor TR4 when the applied voltage reaches a predetermined value.
[0078]
In the example shown in FIG. 1, the transistors TR6 and TR5, the capacitor C1, and the resistors R10 and R11 form a peak detection circuit. When the peak detection circuit detects a voltage peak, a driving signal is supplied to the transistor TR4. Is not limited to the illustrated example.
[0079]
Since the transistor TR5 shown in FIG. 1 utilizes a PN junction between the base and the emitter and a PN junction between the base and the collector, the transistor TR5 is replaced with two diodes (the base-emitter circuit of the transistor TR5). And the circuit between the base and the collector is replaced with a diode).
[0080]
In the example shown in FIGS. 1 and 7, the ignition coil is provided in the magnet generator, and the primary coil of the ignition coil is also used as the ignition power supply coil. However, as shown in FIG. The present invention can also be applied to a configuration in which only the ignition power supply coil We is provided in the machine, and the primary coil W1 of the ignition coil 1 provided outside the magnet generator is connected in parallel to the ignition power supply coil We. .
[0081]
In the case of the configuration shown in FIG. 9, when the current is cut off in the half cycle of one polarity and the half cycle of the other polarity of the output of the ignition power supply coil We, a high voltage induced in the ignition power supply coil We is obtained. The voltage is further boosted by the ignition coil 1, and a high ignition voltage is induced in the secondary coil W2 of the ignition coil. Other operations are the same as in the case of the configuration shown in FIG.
[0082]
In the above description, as shown in FIG. 3, the voltage Vp1 of one polarity half cycle generated by the ignition power supply coil W1 when the engine rotates forward is set to the voltage of the positive half cycle. The voltage Vn of the other half cycle after the voltage Vp1 of the other half cycle is set to the voltage of the negative half cycle. However, the present invention is not limited to this. The half-cycle voltage Vp1 of one polarity generated first by the ignition power supply coil W1 is a negative half-cycle voltage, and the half-cycle voltage Vp1 of the other polarity generated following the half-cycle voltage Vp1 of one polarity is generated. Of course, the voltage Vn may be a positive half cycle voltage.
[0083]
In the present invention, the voltage Vp1 of one polarity half cycle that is generated first by the ignition power supply coil W1 when the engine rotates forward is set to the voltage of the negative half cycle, and the voltage Vp1 of the half cycle of one polarity follows the voltage Vp1. In the case where the half-cycle voltage Vn of the other polarity generated by the above operation is a positive half-cycle voltage, the present invention can be implemented by modifying the circuit shown in FIG. 1 as shown in FIG. . In the circuit shown in FIG. 10, the directions of the first diode 2 and the second diode 3 shown in FIG. 1 are reversed, and a voltage of one polarity half cycle (negative half cycle) is applied to the ignition power supply coil W1. The cathode of the first diode 2 and the anode of the second diode 3 are connected to one end of the ignition power supply coil which becomes a terminal on the low potential side when the induction occurs. The anode of the first diode 2 and the cathode of the second diode 3 are connected to the emitter of the transistor TR1 and the collector of the transistor TR3, respectively, and the collector of the transistor TR1 and the emitter of the transistor TR3 are grounded. Other configurations of the circuit shown in FIG. 10 are the same as those of the circuit shown in FIG. 1, and the operation is also the same as that of the example shown in FIG.
[0084]
Also in the examples shown in FIGS. 7 and 9, by reversing the direction of the diodes 2 and 3, the voltage of one polarity generated by the ignition power supply coil when the engine rotates forward is reduced to a negative half cycle. Voltage.
[0085]
In the example shown in FIG. 2, the rotor of the magnet generator is configured to have three poles so that the ignition power supply coil W1 induces a voltage of one and a half cycle per rotation of the engine. The magnet generator only needs to satisfy the following conditions. (A) Ignition that generates an AC voltage of at least one cycle during which one half-cycle induced voltage of one polarity is followed by a half-cycle induced voltage of the other polarity during one rotation of the internal combustion engine in the forward rotation direction. Have a power coil.
[0086]
(B) The peak position of the induced voltage of the half cycle of one polarity generated first by the ignition power supply coil coincides with the ignition position immediately after the rotation speed of the engine exceeds the set value, and the other polarity subsequently generated The peak position of the induced voltage in the half cycle must match the ignition position when the engine speed is below the set value.
[0087]
(C) the voltage of the half-cycle voltage of one polarity or the other polarity which appears last from the rising position of the half-cycle voltage of the first polarity of the alternating voltage generated by the ignition power supply coil during one revolution of the engine; The angle to the peak position must be less than the rotation angle range of the engine where ignition spark is allowed.
[0088]
In the magnet generator used in the present invention, the magnet rotor has at least two magnetic poles in a part of its circumferential direction, and supplies at least one cycle of AC voltage per rotation near the ignition position of the engine. The number of magnetic poles provided is not limited to three, and the number of magnetic poles provided on the magnet rotor does not necessarily have to be three. For example, in the example shown in FIG. 2, one magnet 14 is fixed in a recess 13a provided in a part of the outer periphery of the flywheel 13, but two magnets arranged in the circumferential direction of the rotor in the recess 13a. The magnets may be fixed and the two magnets may be radially magnetized in different directions to form four magnetic poles. When four magnetic poles are configured, the ignition power supply coil generates two cycles of AC voltage during one rotation of the engine, and the ignition operation is performed four times in a region where the rotation speed of the engine exceeds the set value. become. When the ignition operation is performed a large number of times as described above, the magnetic poles of the magnet rotor are provided so that a series of ignition operations are performed within the explosion stroke of the engine in order to prevent the occurrence of a waste fire that does not contribute to the ignition of the engine. It is preferable to set an area.
[0089]
In the above example, the configuration of the ignition device that ignites one cylinder of the internal combustion engine has been described. However, when the internal combustion engine has a plurality of cylinders, the ignition power supply coils for the number of cylinders are provided, and What is necessary is just to comprise the same ignition device as the above for every ignition power supply coil.
[0090]
In the example shown in FIG. 1, the transistor TR2 is used as a base current bypass switch that bypasses the base current of the first current control transistor TR1 from the transistor, and the base current of the second current control transistor TR3 is used as the base current bypass switch. Although the transistor TR4 is used as a base current bypass switch that bypasses the transistor, a thyristor can be used as a switching element that configures these base current bypass switches.
[0091]
【The invention's effect】
As described above, according to the present invention, in the rotation region where the rotation speed of the internal combustion engine is equal to or less than the set value, the ignition power supply coil generates a voltage of a half cycle of one polarity, and then generates a voltage of a half cycle of the other polarity. The ignition operation is performed only when the ignition occurs, and in the rotation region where the rotation speed of the engine exceeds the set value, the ignition power supply coil generates a half-cycle voltage of one polarity prior to generating a voltage of a half cycle of the other polarity. Since the ignition operation is performed when a voltage is generated, the ignition position is set to a position near top dead center in the low-speed region where the engine speed is equal to or lower than the set value, and the ignition position is set in the region where the engine speed exceeds the set value. The angle can be advanced to a position sufficiently advanced from the top dead center. Therefore, the ignition position can be set so that the engine operates satisfactorily at both low and high speeds of the engine.
[0092]
Further, according to the present invention, since the ignition spark can be generated a plurality of times in a region where the rotation speed of the engine exceeds the set value, the probability of failing to ignite the fuel is reduced, and the emission of unburned gas is prevented. be able to.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a circuit configuration example of an ignition device according to the present invention.
FIG. 2 is a configuration diagram showing a configuration of the ignition device of FIG. 1 together with a configuration example of a magnet generator.
FIG. 3 is a waveform diagram for explaining the operation of the ignition device according to the present invention.
FIG. 4 is a waveform chart for explaining the operation of the ignition device according to the present invention.
FIG. 5 is a waveform chart for explaining the operation of the ignition device according to the present invention.
FIG. 6 is a diagram showing ignition characteristics obtained by the ignition device according to the present invention.
FIG. 7 is a configuration diagram showing another configuration example of the ignition device according to the present invention.
8 (A) and 8 (B) are configuration diagrams showing a configuration example of a current limiting element used in the ignition device of FIG. 7;
FIG. 9 is a configuration diagram showing still another configuration example of the ignition device according to the present invention.
FIG. 10 is a circuit diagram showing another example of the circuit configuration of the ignition device according to the present invention.
[Explanation of symbols]
1 ignition coil
W1 primary coil (ignition power supply coil)
W2 Secondary coil
2 First diode
3 Second diode
4 First current control circuit
TR1 First current control transistor
4a First transistor control circuit
5. Second current control circuit
TR3 Second current control transistor
5a Second transistor control circuit
TR4 to TR7 Transistor
C1 capacitor
R7 to R11 resistance
6 Spark plug

Claims (11)

An ignition power supply coil provided on a magnet generator driven by the internal combustion engine for inducing at least one cycle of AC voltage during one rotation of the internal combustion engine in a positive direction;
When a voltage of a first half cycle of one polarity of the positive and negative half cycles of the AC voltage induced by the ignition power supply coil is generated while the internal combustion engine makes one rotation in the positive direction, the ignition power supply coil side generates a base. A first current control transistor that is supplied with a current and conducts to substantially short-circuit the ignition power supply coil; and a voltage across the ignition power supply coil when the first current control transistor is conductive. And a first transistor control circuit for performing a control operation of turning off the first current control transistor when the voltage of the ignition power supply reaches a predetermined level. A first current control circuit for inducing a high voltage in the coil;
A second current control transistor for supplying a base current from the ignition power supply coil side when the ignition power supply coil induces a half-cycle voltage of the other polarity and conducting to substantially short-circuit the ignition power supply coil; When the voltage across the ignition power supply coil reaches a predetermined level or reaches a peak when the second current control transistor is on, the second current control transistor is turned off. A second transistor control circuit for performing a control operation, a second current control circuit for generating a high voltage in the ignition power supply coil by shutting off the second current control transistor;
Boosting means for generating a high ignition voltage by increasing a voltage induced in the ignition power supply coil when the first current control transistor or the second current control transistor is turned off,
An operation of the first transistor control circuit so that the first transistor control circuit does not perform a control operation for turning off the first current control transistor when the rotation speed of the internal combustion engine is equal to or lower than a set value; An ignition device for an internal combustion engine, wherein the sensitivity is set. An ignition power supply coil provided in a magnet generator driven by the internal combustion engine for inducing at least one cycle of AC voltage during one rotation of the internal combustion engine in a positive direction;
When the voltage of the half cycle of one polarity, which appears first, of the positive and negative half cycles of the AC voltage induced by the ignition power supply coil while the internal combustion engine makes one rotation in the positive direction, the terminal becomes a high potential side terminal. First and second diodes having an anode and a cathode connected to one end of the ignition power supply coil, respectively;
A collector-emitter circuit is connected in parallel to both ends of the ignition power supply coil through the first diode, and when a voltage of one polarity half cycle is induced in the ignition power supply coil, a base current is generated from the ignition power supply coil side. A first current control transistor that is applied and conducts, and the first current when the voltage across the ignition power supply coil reaches a predetermined level when the first current control transistor is conductive. A first transistor control circuit for performing a control operation of turning off the control transistor, a first current control circuit for inducing a voltage in the ignition power supply coil by shutting off the first current control transistor; ,
A collector-emitter circuit is connected in parallel to both ends of the ignition power supply coil through the second diode, and when a voltage of the other polarity half cycle is induced in the ignition power supply coil, a base current is generated from the ignition power supply coil side. A second current control transistor that is given and turned on, and when the voltage across the ignition power supply coil reaches a predetermined level or reaches a peak when the second current control transistor is turned on. A second transistor control circuit for performing a control operation of turning off the second current control transistor, wherein a second voltage is induced in the ignition power supply coil by turning off the second current control transistor. Current control circuit,
Boosting means for generating a high ignition voltage by increasing a voltage induced in the ignition power supply coil when the first current control transistor or the second current control transistor is turned off,
An operation of the first transistor control circuit so that the first transistor control circuit does not perform a control operation for turning off the first current control transistor when the rotation speed of the internal combustion engine is equal to or lower than a set value; An ignition device for an internal combustion engine, wherein the sensitivity is set. An ignition power supply coil provided in a magnet generator driven by the internal combustion engine for inducing at least one cycle of AC voltage during one rotation of the internal combustion engine in a positive direction;
When the voltage of one half cycle of one polarity, which appears first among the positive and negative half cycles of the AC voltage induced by the ignition power supply coil during one rotation of the internal combustion engine in the positive direction, becomes a terminal on the low potential side when the voltage is induced. First and second diodes having a cathode and an anode connected to one end of the ignition power supply coil, respectively;
A collector-emitter circuit is connected in parallel to both ends of the ignition power supply coil through the first diode, and when a voltage of one polarity half cycle is induced in the ignition power supply coil, a base current is generated from the ignition power supply coil side. A first current control transistor that is applied and conducts, and the first current when the voltage across the ignition power supply coil reaches a predetermined level when the first current control transistor is conductive. A first transistor control circuit for performing a control operation of turning off the control transistor, a first current control circuit for inducing a voltage in the ignition power supply coil by shutting off the first current control transistor; ,
A collector-emitter circuit is connected in parallel to both ends of the ignition power supply coil through the second diode, and when a voltage of the other polarity half cycle is induced in the ignition power supply coil, a base current is generated from the ignition power supply coil side. A second current control transistor that is given and turned on, and when the voltage across the ignition power supply coil reaches a predetermined level or reaches a peak when the second current control transistor is turned on. A second transistor control circuit for performing a control operation of turning off the second current control transistor, wherein a second voltage is induced in the ignition power supply coil by turning off the second current control transistor. Current control circuit,
Boosting means for generating a high ignition voltage by increasing a voltage induced in the ignition power supply coil when the first current control transistor or the second current control transistor is turned off,
An operation of the first transistor control circuit so that the first transistor control circuit does not perform a control operation for turning off the first current control transistor when the rotation speed of the internal combustion engine is equal to or lower than a set value; An ignition device for an internal combustion engine, wherein the sensitivity is set. 4. A current limiting element for limiting a current flowing from the ignition power supply coil to the first current control circuit side is inserted between the ignition power supply coil and the first current control circuit. The ignition device for an internal combustion engine according to claim 1. The internal combustion engine according to any one of claims 1 to 4, wherein the boosting means comprises an ignition coil provided in the magnet generator, and a primary coil of the ignition coil constitutes the ignition power supply coil. Engine ignition device. The magnet generator is made of a ferromagnetic material and is fixed in a flywheel attached to a crankshaft of an internal combustion engine and a recess formed in a part of an outer periphery of the flywheel, and is fixed in a radial direction of the flywheel. A magnet rotor having one magnetized permanent magnet and having a three-pole magnet field formed by the permanent magnet and the outer periphery of the flywheel on both sides of the recess; and a magnetic pole of the magnet rotor An armature formed by winding the ignition power supply coil around an iron core having a magnetic pole portion facing the armature, and the ignition power supply coil receives one half cycle voltage of one polarity while the internal combustion engine makes one rotation in the positive direction. A half-cycle AC voltage, in which a half-cycle voltage of the other polarity and a half-cycle voltage of one polarity appear in order, is induced,
The peak position of the voltage in the first half cycle of the AC voltage induced in the ignition power supply coil and the peak position of the induced voltage in the second half cycle during the rotation of the internal combustion engine during one rotation of the internal combustion engine are respectively defined by the rotation of the internal combustion engine. The ignition power source coincides with the ignition position immediately after the speed exceeds the set value and the ignition position when the rotational speed of the engine is equal to or less than the set value, and the internal combustion engine makes one rotation in the forward direction. The distance between the magnetic poles of the magnet field of the magnet rotor and the magnet so that the peak position of the voltage of the last half cycle of the AC voltage induced in the coil falls within the rotation angle range of the engine where ignition spark is allowed to occur. 5. The ignition device for an internal combustion engine according to claim 1, wherein a positional relationship between the rotor and the armature is set. The magnet generator is made of a ferromagnetic material and is fixed in a flywheel attached to a crankshaft of an internal combustion engine and a recess formed in a part of an outer periphery of the flywheel, and is fixed in a radial direction of the flywheel. A magnet rotor having one magnetized permanent magnet and having a three-pole magnet field formed by the permanent magnet and the outer periphery of the flywheel on both sides of the recess; and a magnetic pole of the magnet rotor An armature formed by winding an ignition coil having a primary coil constituting the ignition power supply coil and a secondary coil magnetically coupled to the primary coil on an iron core having a magnetic pole portion facing the internal combustion engine. During one rotation in the forward direction, the ignition power supply coil has a half-cycle voltage of one polarity, a half-cycle voltage of the other polarity, and a half-cycle voltage of one polarity, which appear in order. There are configured to induce,
The peak position of the voltage in the first half cycle of the AC voltage induced in the ignition power supply coil and the peak position of the induced voltage in the second half cycle during the rotation of the internal combustion engine during one rotation of the internal combustion engine are respectively defined by the rotation of the internal combustion engine. The ignition power source coincides with the ignition position immediately after the speed exceeds the set value and the ignition position when the rotational speed of the engine is equal to or less than the set value, and the internal combustion engine makes one rotation in the forward direction. The distance between the magnetic poles of the magnet field of the magnet rotor and the magnet so that the peak position of the voltage of the last half cycle of the AC voltage induced in the coil falls within the rotation angle range of the engine where ignition spark is allowed to occur. The positional relationship between the rotor and the armature is set,
The ignition device for an internal combustion engine according to any one of claims 1 to 4, wherein the ignition coil constitutes the booster. The first transistor control circuit includes a first current control circuit base provided so as to conduct when a drive signal is supplied and to bypass a base current of the first current control transistor from the transistor. When the voltage across the ignition power supply coil reaches a predetermined level when the first current control transistor is conductive, the current bypass switch is driven to the first current control circuit base current bypass switch. The ignition device for an internal combustion engine according to any one of claims 1 to 7, further comprising a first side switch drive circuit for a current control circuit that supplies a signal. The second transistor control circuit includes a second current control circuit base provided to conduct when a drive signal is supplied and to bypass a base current of the second current control transistor from the transistor. A current bypass switch and a base current for the second current control circuit when it is detected that the voltage across the ignition power supply coil has reached a predetermined level when the second current control transistor is conducting. The ignition device for an internal combustion engine according to any one of claims 1 to 8, further comprising a second side switch drive circuit for a control circuit that supplies a drive signal to the side switch. The second transistor control circuit includes a second current control circuit base provided to conduct when a drive signal is supplied and to bypass a base current of the second current control transistor from the transistor. A drive signal is supplied to the current bypass switch and the base current bypass switch for the second current control circuit when the voltage across the ignition power supply reaches a peak when the second current control transistor is conducting. The ignition device for an internal combustion engine according to any one of claims 1 to 8, further comprising a peak detection circuit that provides: The second transistor control circuit is configured to conduct when a drive signal is applied, and to provide a second control circuit base current provided to bypass the base current of the second current control transistor from the transistor. A drive signal is supplied to the bypass switch and the second control circuit base current bypass switch when the voltage across the ignition power supply coil reaches a peak when the second current control transistor is conducting. A drive signal is supplied to the peak detection circuit and the base current bypass switch for the second control circuit when the voltage across the ignition power supply reaches a set level when the second current control transistor is conducting. A second current control circuit bypass switch drive circuit for providing
The set level is a peak value of a voltage generated at both ends of the primary coil through which a current flows due to conduction of the second current control transistor when the rotation speed of the internal combustion engine reaches a set cutoff value switching speed. 9. The ignition device for an internal combustion engine according to claim 1, wherein the ignition devices are set to be substantially equal.

Images