JPH0712692Y2 - Non-contact ignition device for internal combustion engine - Google Patents

Description

The present invention relates to a so-called capacitor charging / discharging type non-contact ignition device for an internal combustion engine, and more particularly to a non-contact ignition device for an internal combustion engine capable of preventing reverse rotation of the internal combustion engine. It is about.

[Conventional technology]

When a heavy load is suddenly applied while the internal combustion engine is rotating normally, or when a force to physically reverse the rotation is applied, the internal combustion engine may be reversed.

However, since the non-contact ignition device for an internal combustion engine that has been provided conventionally performs the ignition operation at substantially the same ignition timing as the forward rotation even when the internal combustion engine reverses, the internal combustion engine reverses as described above. At that point, the reversal would continue. Therefore, there is a possibility that a personal injury or the like may be caused in a small work machine equipped with the above-mentioned conventional non-contact ignition device for an internal combustion engine, such as a chain saw.

Therefore, conventionally, as a non-contact ignition device of an internal combustion engine that can prevent the reverse rotation of the internal combustion engine by not performing the ignition operation at the time of reverse rotation even if the internal combustion engine tries to reverse, as disclosed in Japanese Utility Model Publication No. Sho 49-113033. Ignition device and actual development Sho 51-5643
The ignition device described in Japanese Patent No. 6 has been provided.

All of these devices charge the rectified output of the magnet generator to a capacitor and respond to an ignition signal obtained from an ignition signal generator provided separately from the magnet generator during normal rotation of the internal combustion engine. Ignition operation is performed by discharging the charge stored in the capacitor, and when the internal combustion engine reverses, the ignition signal is bypassed by a switching element to be invalidated to prevent the ignition operation and prevent reverse rotation of the internal combustion engine. It was a thing. In order to realize such an operation, these devices are provided with the magnet generator and the ignition signal generator separately, and the ignition signal generator is provided both during normal rotation and reverse rotation of the internal combustion engine. The ignition signal is generated at substantially the same angular position from the above, and the ignition is performed only in a small part of the period in which the induced voltage of one polarity is obtained in the forward rotation of the magnet generator and the other polarity is obtained in the reverse rotation. The precondition is that an induced voltage is generated from the signal generator.

However, in such a conventional ignition device, since the magnet generator and the ignition signal generator are separately provided as described above, the number of parts is increased and the cost is increased, and two generators are used. Since they have to be attached separately, there is a drawback that the attachment is troublesome.

On the other hand, in a conventional ignition device that does not consider reverse rotation prevention of an internal combustion engine, in order to eliminate such a defect, both an exciter coil for obtaining ignition energy and a trigger coil for obtaining an ignition signal are wound. A single magnet generator equipped with a core is generally used (for example, JP-A-61-1869 and JP-A-60-184969).
In addition, in such an ignition device, the above-mentioned actual exploitation 49-11303
Even when trying to apply the technology described in Japanese Patent Publication No. 3 or Japanese Utility Model Laid-Open No. 51-56436, in the technology described in Japanese Utility Model Publication No. 49-113033 or Japanese Utility Model Publication No. 51-56436, Since such prerequisites are indispensable, application of such technology was impossible.

As described above, conventionally, it has not been possible to simultaneously satisfy both the demand for preventing reverse rotation of the internal combustion engine and the demand for cost reduction and easy mounting using a single magnet generator.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned prior art. Even if the internal combustion engine tries to rotate in the reverse direction, the ignition operation is not performed during the reverse rotation, so that the reverse rotation of the internal combustion engine can be reliably prevented, and a single magnet is used. The object of the present invention is to provide a non-contact ignition device for an internal combustion engine, which requires only a generator, has a small number of parts, is inexpensive, and is easy to install.

[Means for solving problems]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention solves the above problems by providing a rotor having magnetic poles, a core arranged to face the rotor and having both an exciter coil and a trigger coil wound around it, and ignition for charging a positive induced voltage of the exciter coil. Charging / discharging capacitor, and a first switching element that is triggered when the positive induced voltage of the trigger coil reaches a predetermined trigger level to conduct, and supplies the charge of the ignition charging / discharging capacitor to the ignition coil. In a non-contact ignition device for an internal combustion engine having a second switching element, which is triggered when the negative induced voltage of the exciter coil reaches a predetermined trigger level to short-circuit the positive induced voltage of the trigger coil. And the first switching element is triggered prior to the second switching element during normal rotation of the internal combustion engine. , The second switching element is triggered so that the second switching element is triggered prior to the first switching element during reverse rotation of the internal combustion engine. The above-mentioned predetermined trigger level is set.

[Action]

According to the present invention, when the internal combustion engine rotates in the normal direction and in the reverse direction,
The positive induced voltage of the exciter coil charges the charging / discharging capacitor for ignition.

Since these trigger levels are set so that the first switching element is triggered prior to the second switching element during normal rotation of the internal combustion engine, the positive induced voltage of the trigger coil is set to the predetermined trigger voltage. When the level is reached, the first switching element is triggered and becomes conductive,
At this point, the charge of the ignition charging / discharging capacitor is supplied to the ignition coil for ignition. Therefore, during normal rotation of the internal combustion engine, the ignition operation is performed at the desired ignition timing. The second switching element is triggered and conducts when the negative induced voltage of the exciter coil reaches a predetermined level, and the positive induced voltage of the trigger coil is short-circuited. Since the switching element has already been triggered, there is no problem in the ignition operation.

On the other hand, during reverse rotation of the internal combustion engine, since these trigger levels are set so that the second switching element is triggered prior to the first switching element, the positive induced voltage of the trigger coil causes the first switching element to move. Before the trigger level of the element is reached, the second switching element is triggered and becomes conductive, whereby the positive induced voltage of the trigger coil is short-circuited, and the positive induced voltage of the trigger coil is changed to the first switching element. The trigger level of the first switching element is not always reached, and as a result, the charging charge of the ignition charging / discharging capacitor is not supplied to the ignition coil.
It is a misfired one. Therefore, even if the internal combustion engine reverses for some reason, the reverse rotation is not continued and the reverse rotation is prevented.

Further, in the present invention, only the rotor having magnetic poles and the core, which is arranged facing the rotor and has both the exciter coil and the trigger coil wound therein, are provided. Unlike the above, since a single magnet generator is used, the number of parts is small, the cost is low, and the mounting is easy.

〔Example〕

 The present invention will be described below based on the embodiments shown in the drawings.

In the drawing, (1) is a rotor having magnetic poles (2) and (3), which is attached to a rotary shaft of an engine so as to rotate in synchronization with the internal combustion engine. In the case of the embodiment shown in the drawings, the rotor (1) is configured by embedding a magnet (5) and magnetic poles (2) and (3) in a non-magnetic body (4) made of aluminum.
(3) is exposed on the outer peripheral surface of the rotor (1). Also,
The magnet (5) is connected to the magnetic poles (2) and (3) so that the magnetic poles (2) and (3) are different from each other.

Further, (6) is a U-shaped core arranged to face the rotor (1), and an exciter coil (7) and a trigger coil (8) are respectively wound around the legs (6a) and (6b). . The surfaces of the legs (6a) and (6b) facing the rotor (1) are each formed in an arc shape so that the distance between the legs (6a) and (6b) is substantially constant. Further, in the case of the embodiment shown in the drawings, the leg (6b) is provided with an extension (6c) in the reverse direction of the rotor (1) as shown in the first drawing, whereby the induced voltage waveform of the trigger coil (8) rises. The inclination is largely changed between low speed and high speed, and the ignition timing of the internal combustion engine is automatically advanced according to the engine speed. In addition, the present invention does not necessarily require the above-mentioned extension (6c).

Further, as shown in the second illustration, the exciter coil (7)
Has a diode (9) and a charging / discharging capacitor for ignition (10)
And the primary coil (11a) of the ignition coil (11) are connected in series to form a charging circuit for charging the positive induced voltage of the exciter coil (7), and the ignition charge / discharge capacitor (10) ) Is charged with the positive induced voltage of the exciter coil (7).

The ignition charging / discharging capacitor (10) is the anode / cathode of the thyristor (12) as the first switching element and the primary coil (11a) of the ignition coil (11).
Are connected in series with each other, and these constitute a discharge circuit for discharging the charge stored in the charging / discharging capacitor (10) for ignition. The thyristor (12) is the first switching element.
Is charged and supplied to the ignition coil (11) when the ignition charge / discharge capacitor (10) is charged.

The secondary coil (11b) of the ignition coil (11)
A spark plug (13) is connected to the. A backflow prevention diode (14) is connected between the anode and cathode of the thyristor (12).

Further, a trigger coil (8) is connected via a Zener diode (15) and a resistor (16) is connected between the gate and the cathode of the thyristor (12) which is the first switching element. The thyristor (12), which is a switching element of No. 1, is triggered and becomes conductive when the positive induced voltage of the trigger coil (8) reaches a predetermined trigger level V _T1 . The Zener diode (15) determines the trigger level V _T1 .
The value of the positive induced voltage of the trigger coil (8) when this breaks over becomes the trigger level V _T1 . In addition, the Zener diode (15) may be replaced with a resistor having a required resistance value.

Furthermore, the anode and cathode of a thyristor (17), which is a second switching element, are connected to both ends of the trigger coil (8) via a diode (18), and a thyristor (17) that is a second switching element is connected. The positive induced voltage of the trigger coil (8) is short-circuited when it is triggered and becomes conductive.

Furthermore, the gate of the thyristor (17) which is the second switching element is connected to one end of the exciter coil (7), and the cathode of the thyristor (17) which is the second switching element is connected via the diode (19) to the exciter coil (17). The resistor (20) is connected between the gate and cathode of the thyristor (17), which is the second switching element, and the second thyristor (17) is the exciter coil (17). When the negative induced voltage of 7) reaches a predetermined trigger level V _T2 , it is triggered and becomes conductive.

When the internal combustion engine rotates in the normal direction, the thyristor (12) which is the first switching element is triggered prior to the thyristor (17) which is the second switching element, and when the internal combustion engine rotates in the reverse direction, the thyristor (the second switching element) ( 17) is the thyristor (1) which is the first switching element.
2) above trigger level V so that it will be triggered ahead of
_T1 and trigger level V _T2 are determined. In this way, the trigger levels V _T1 and V _T2 can be determined because the induced voltage waveforms of the exciter coil (7) and the trigger coil (8), especially the rising thereof, during forward rotation and reverse rotation of the internal combustion engine. It is based on the fact that the waveforms of are different. Therefore, the determination of the trigger levels V _T1 and V _T2 is specifically made by selecting the elements of the thyristors (12) (17) and the Zener diode (15), etc. Depending on the exciter coil (7) and trigger coil (8)
It is decided experimentally by changing the number of turns.

Next, the operation of the contactless ignition device for an internal combustion engine having the above configuration will be described. First, when the internal combustion engine rotates in the forward direction, the exciter coil (7)
If the trigger coil (8) is in an unloaded state, the exciter coil (7) has a voltage V of the waveform shown in FIG. 3 (a).
_Ex.c. is induced, and the voltage V _{Tr.c. of the} waveform shown in FIG. _3B is induced in the trigger coil (8).

When a positive voltage of the induced voltage V _Ex.c. of the exciter coil (7) is obtained, the diode (9) → the ignition charge / discharge capacitor (10) → the primary coil of the ignition coil (11) ( An electric current flows through the path of 11a) and charges the charging / discharging capacitor (10) for ignition.

Then, at the time of normal rotation of the internal combustion engine, these trigger levels V _T1 and V _T2 are set so that the first switching element thyristor (12) is triggered prior to the second switching element thyristor (17). (In the state shown in FIG. 3, the thyristor (12) is set to be triggered before the thyristor (17) by Δt ₁ hour).
_Therefore , at time T ₁ when the positive voltage of the induced voltage V _Tr.c. of the trigger coil (8) reaches the trigger level V _T1 , the _zener diode (15) breaks over and the thyristor, which is the first switching element, breaks down. A trigger current is supplied to the gate of (12), and the thyristor (12) is triggered and becomes conductive. As a result, the charge stored in the charging / discharging capacitor (10) for ignition is discharged to the primary coil (11a) of the ignition coil (11) through the anode / cathode of the thyristor (12), and then to the secondary coil (11b) thereof. A voltage is induced to generate the desired spark at the spark plug (13).

Therefore, during normal rotation of the internal combustion engine, the ignition operation is performed at the desired ignition timing (T _{1 in} the case of the third illustration).

Even during normal rotation of the internal combustion engine, the thyristor (17), which is the second switching element, has the exciter coil (7).
Negative voltage of the induced voltage V _Ex.C. conducts is triggered when T ₂ reaches a trigger level V _T2 of, thereby the induced voltage V _Tr.C. farmland Tadashino trigger coil (8) The voltage is the anode / cathode of the thyristor (17) and the diode (18)
However, since the first switching element, the thyristor (12), has already been triggered at this point in time T ₂ , it does not hinder the ignition operation.

On the other hand, when the internal combustion engine reverses, the exciter coil (7)
If the trigger coil (8) and the trigger coil (8) are in an unloaded state, the exciter coil (7) has a voltage V of the waveform shown in FIG.
_Ex.c. is induced, the voltage V _{Tr.c. of the} waveform shown in Fig. 4 (b) is induced in the trigger coil (8), and the positive and negative of these waveforms are in the normal rotation of the internal combustion engine. The opposite is true.

When a positive voltage of the induced voltage V _Ex.c. of the exciter coil (7) is obtained, the diode (9) → the charging / discharging capacitor (10) for ignition, as in the normal rotation of the internal combustion engine. ) → Primary coil (11) of ignition coil (11)
Current flows through the path of a), and the charging / discharging capacitor for ignition (1
Charge to 0).

Then, at the time of reverse rotation of the internal combustion engine, these trigger levels V _T1 , V _T2 are set so that the thyristor (17) which is the second switching element is triggered prior to the thyristor (12) which is the first switching element. (In the state shown in FIG. 4, the thyristor (17) has Δt _{2 for the} thyristor (12)
Is set to be triggered prior to
_{Before the} positive voltage of the induced voltage V _Tr.c. of the trigger coil (8) reaches the trigger level V _T1 , the negative voltage of the induced voltage V _Ex.c. of the exciter coil (7) is the trigger level.
When V _T2 is reached, at that time point T ₃ , the thyristor (17) which is the second switching element is triggered and becomes conductive, whereby the positive voltage of the induced voltage V _Tr.c. of the trigger coil (8) becomes thyristor ( 17) The anode / cathode of 17) and the diode (18) are short-circuited, and the induced voltage V _Tr.c. of the trigger coil (8) does not reach the trigger level V _T1 and is the first switching element. Thyristor (1
The trigger of 2) is always blocked. Therefore, the charging charge of the charging / discharging capacitor for ignition (10) is not discharged to the ignition coil (11), and the state of misfire is maintained. As a result, even if the internal combustion engine reverses for some reason, the reverse rotation is not continued and is prevented.

Further, the contactless ignition device includes a single magnet including a core (6) wound with both an exciter coil (7) for obtaining ignition energy and a trigger coil (8) for obtaining an ignition signal. Since only a generator is used,
Compared with the above-mentioned conventional ignition device capable of preventing reverse rotation, the number of parts is small, the cost is low, and the mounting is easy.

[Effect of device]

According to the present invention, even if the internal combustion engine tries to rotate in the reverse direction for some reason, the ignition operation is blocked during the reverse rotation, and the reverse rotation of the internal combustion engine can be reliably prevented, and only a single magnet generator is used. The number of parts is small, the cost is low, and the mounting is easy.

[Brief description of drawings]

1 shows an embodiment of the present invention. FIG. 1 is a partially cutaway front view showing a part of a non-contact ignition device of the present invention, and FIG. 2 is a circuit diagram of the non-contact ignition device of the present invention. FIG. 3 is a waveform diagram of an induced voltage when the internal combustion engine is rotating normally, (a) is a waveform diagram of the induced voltage of the exciter coil, (b) is a waveform diagram of the induced voltage of the trigger coil, and FIG. 4 is a diagram when the internal combustion engine is reversely rotated. In the induced voltage waveform diagram, (a) is an induced voltage waveform diagram of the exciter coil, and (b) is an induced voltage waveform diagram of the trigger coil. (1) …… Rotor, (2) (3) …… Magnetic pole, (6) ……
Core, (7) ... Exciter coil, (8) ... Trigger coil, (10) ... Charging / discharging capacitor for ignition, (11) ...
Ignition coil, (12) thyristor (first switching element), (13) Ignition plug, (17)
... Thyristor (second switching element).

Claims (1)

[Scope of utility model registration request] 1. A rotor having magnetic poles, a core arranged to face the rotor and wound around both an exciter coil and a trigger coil, and an ignition charging / discharging capacitor for charging a positive induced voltage of the exciter coil. Non-contact of an internal combustion engine having a first switching element that is triggered when the positive induced voltage of the trigger coil reaches a predetermined trigger level and is turned on to supply the charge of the ignition charge / discharge capacitor to the ignition coil. In the ignition device, a second switching element is provided, which is triggered when the negative induced voltage of the exciter coil reaches a predetermined trigger level and conducts to short-circuit the positive induced voltage of the trigger coil.
The first switching element is triggered prior to the second switching element during normal rotation of the internal combustion engine, and the second switching element is triggered prior to the first switching element during reverse rotation of the internal combustion engine, A contactless ignition system for an internal combustion engine, wherein the predetermined trigger level at which the first switching element is triggered and the predetermined trigger level at which the second switching element is triggered are set.