JPS6123662Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for an internal combustion engine, and more particularly to an ignition device equipped with a reverse rotation prevention circuit for the engine.

A conventional transistor ignition system (TCI), i.e., a unidirectional component of voltage induced in the primary winding of a generator coil comprising a primary winding and a secondary winding, by the rotation of a permanent magnet rotor of a magnet generator. When a short circuit occurs due to a switching element such as a transistor, and the short circuit current reaches a certain set value, this is detected and the switching element is turned off to cut off the short circuit current, and a sudden change in the current flowing through the generator coil primary winding causes the generator coil secondary In an ignition system that induces high voltage in the secondary winding to ignite, even if the engine rotates in the opposite direction for some reason during operation, or if the operator accidentally rotates the engine in the wrong direction, the primary winding of the generator coil The electromotive force induced in the engine generates alternating positive and negative components, although their magnitudes are different, so the short circuit current caused by the positive electromotive force that occurs when the engine rotates in reverse is normal. As in the case of directional rotation, the switching element interrupts the short-circuit current, so the ignition timing varies, but there is a problem in that the engine continues to rotate in the opposite direction or is placed in a state where it can be started in reverse rotation.

Such a conventional ignition device will be further explained with reference to FIGS. 1 to 3. In addition, in FIGS. 2 to 5, TDC indicates the top dead center position of the internal combustion engine. FIG. 1 is a circuit diagram of an ignition device equipped with a reverse rotation prevention circuit A according to the present invention.If the reverse rotation prevention circuit A is removed, the other parts are the same as the conventional device. Note that B indicates a short-circuit control semiconductor circuit. Magnet generators are well-known, but when the permanent magnet rotor 1 (three magnetic poles are shown in the illustration, two may be used) coupled to the engine rotates, the primary winding 2 of the generator coil rotates. As shown in FIG _. 2, for each cycle of , a waveform electromotive force with negative electromotive forces V ₁ and V ₃ is generated immediately before and after the positive electromotive force V 2 . _The current I ₁ due to the negative electromotive force V ₁ in FIG _.
1 to a switching element, for example a transistor 5
, the transistor 5 becomes conductive, and the current I ₂ due to the positive electromotive force V ₂ of the primary winding of the generator coil is short-circuited. A part of the current I ₂ due to the positive electromotive force V ₂ also flows through the voltage divider circuit consisting of resistors 41 and 42 connected to the base of the transistor 4, so the positive electromotive force V ₂ increases and the short circuit current I ₂ The voltage dividing circuit detects that the magnitude of the voltage has reached the set value I ₀ , and when the magnitude reaches the set value I ₀ , the transistor 4 is turned on, and therefore the transistor 5 is turned off to cut off the short-circuit current. Therefore, at the time _t1 when the short circuit current is cut off, a high voltage is induced in the generator coil secondary winding 3, and ignition is performed. The current I ₃ due to the next negative electromotive force V ₃ flows through the series circuit of the diode 6 and the resistor 7 with a limited magnitude, similar to the current I ₁ .

In such a conventional ignition system, if the engine rotates in the opposite direction for some reason, or if the engine rotates in the opposite direction due to an operator's mistake in the starting direction, the permanent magnet rotor 1 will also rotate in the opposite direction, causing the primary generator coil to rotate in the opposite direction. The direction of the electromotive force generated in the winding 2 is also reversed, and this electromotive force causes a radio wave as shown in Figure 4 to flow, and the currents I' ₁ and I' ₃ due to the positive electromotive force are transferred to the transistor 5.
A short-circuit current occurs due to the conduction of , and a current I' ₂ due to the negative electromotive force flows through the series circuit of the diode 6 and the resistor 7. In this case, the magnitude of the currents I' ₁ and I' ₃ often exceeds the set value I ₀ that should interrupt the short-circuit current flowing through the primary winding 2 of the generator coil, so the current
At times t ₂ and t ₃ when I' ₁ and I' ₃ respectively reach the set value I ₀ , the short-circuit current is interrupted by turning off the transistor 5 and ignition occurs. Among them, ignition timing
t ₂ is the ignition timing t ₁ (third
(Figure 4 shows reverse rotation, so the direction of rotation is opposite to Figure 3), so the engine is in a state where it can fully demonstrate its performance. However, it will start up and be ready for operation. However, since the ignition timing t ₃ due to the current I' ₃ is too late for ignition, the engine does not start. Therefore, with conventional ignition systems,
Even when the engine rotates in reverse, the current due to the positive electromotive force initially generated by the rotation of the permanent magnet rotor 1
Short-circuit current detection and interruption are performed for I′ ₁ ,
The engine can be started by ignition at the ignition timing _t2 , and the engine can continue to rotate in the opposite direction, which sometimes poses a dangerous problem.

The purpose of the present invention is to provide a reverse rotation prevention circuit A to the conventional transistor ignition system (TCI) as described above to prevent or limit the short circuit current that causes ignition when the engine rotates in reverse. The object of the present invention is to provide an ignition device equipped with the following.

In this invention, when the engine rotates in the normal direction and when the engine rotates in the opposite direction, the order of generation of positive and negative electromotive force generated in the primary winding of the generator coil of the magnet generator, and its waveform and height. After detecting the occurrence of the first negative electromotive force in each cycle of engine rotation, we installed a reverse rotation prevention circuit A, which includes a thyristor 8 that becomes conductive only for a predetermined period, in the primary winding of the generator coil. and the short-circuit control semiconductor circuit B in the short-circuit current path. Therefore, the short-circuit current _I2 due to the positive electromotive force flows only during the conduction period of the thyristor 8 of the reverse rotation prevention circuit A, and during this period, the short-circuit control semiconductor circuit B detects and interrupts the short-circuit current without any problem. However, when the engine rotates in reverse as shown in FIG.
Since this is prevented by the non-conduction of the thyristor 8 of the reverse rotation prevention circuit A, detection and interruption of the short circuit current based on this forward electromotive force are not performed, and therefore ignition is not performed. Therefore, reverse rotation of the engine can be reliably prevented.

The anti-reverse rotation ignition device according to the present invention will be explained with reference to FIGS. 1 and 5. As already mentioned, block A in FIG. 1 is a reverse rotation prevention circuit, which is a characteristic electric circuit of the present invention, and is a short circuit current path between the power generation coil primary winding 2 and the short circuit control semiconductor circuit B. is inserted into. The thyristor 8 in the reverse rotation prevention circuit A is arranged so that the current due to the positive electromotive force generated in the power generation coil primary winding 2, that is, the short circuit current due to conduction of the transistor 5 of the short circuit control semiconductor circuit B becomes a forward current. The thyristor is connected to the thyristor of the rotation of the engine, and is configured to allow only a short-circuit current due to a forward electromotive force following a reverse electromotive force induced in the primary winding 2 of the power generation coil to flow through each thyristor of rotation of the engine. For controlling the thyristor 8 for this purpose, a control circuit consisting of a diode 9, a capacitor 10, a diode 11, resistors 12, 13 and 14 and a diode 16 is connected.
This control circuit generates a short-circuit current I ₂ (Figure 3) due to a positive electromotive force that is detected and interrupted by a short-circuit control semiconductor circuit B to generate an ignition signal when the engine rotates in the normal direction. A charging circuit passes through a diode 11, a resistor 12, a capacitor 10, and a diode 16 to charge the capacitor 10 with a current _I1 caused by a negative electromotive force, and the charge of the capacitor 10 is passed through a resistor 13 and the gate/cathode circuit of the thyristor 8. and a discharge circuit for discharging the battery. Further, the diode 9 is connected in series with the thyristor 8 and in parallel with the charging circuit.

Next, to explain the operation of the reverse rotation prevention circuit A having the configuration described above, when the engine is rotating in the normal direction, the power generating coil primary winding 2 is Positive electromotive force V ₂ as shown
Reverse electromotive forces V ₁ and V ₃ are generated before and after the third
Let the currents I ₁ , I ₂ and I ₃ shown in the figure flow. At this time, first, the current I ₁ due to the first reverse electromotive force V ₁ is divided into various parts of the reverse rotation prevention circuit A as follows.

The shunt path in FIG. 1 passes through the charging circuit of the capacitor 10, and is a path from the generator coil primary winding 2 to the diode 11, from the resistor 12, through the capacitor 10, and to the diode 16.
It returns to the power generation coil primary winding 2 from the resistor 7 and diode 6 of the short-circuit control semiconductor circuit B. Therefore, capacitor 10 is charged to the polarity shown.

The second branch path is from the generator coil primary winding 2 to the diode 11 and from the resistors 12 and 13 to the thyristor 8.
This is the gate/cathode circuit of the diode 16, the resistor 7, and the diode 6. A part of this circuit also serves as a discharge circuit for the capacitor 10. The current passing through this second branch path triggers the thyristor 8 to become conductive.

Next, the third branch path is a path from the generator coil 2 through a series circuit of a resistor 14 and a diode 16, and a resistor 15 parallel to this series circuit.
The branch flow path adjusts the charging voltage of the capacitor 10, and also allows the current to flow through the resistor 14 or 15, so that the change in magnetic flux generated in the generator coil iron core due to the rotation of the permanent magnet rotor 1 causes the normal short circuit current to be interrupted. It functions to prevent high voltage from being induced in the secondary coil 3 at other times. Note that the resistor 15 can be omitted by providing the resistor 14, or conversely, if the resistor 15 is provided, the resistor 14 can also be omitted.

Next, when the current I ₁ due to the reverse electromotive force V ₁ decreases and reaches a certain value, the capacitor 10 is discharged through the discharge circuit including the gate/cathode circuit of the thyristor 8, so that the thyristor ₈ Even after the flow stops, it continues to remain conductive.

When the positive current I ₂ due to the positive electromotive force V ₂ starts to flow while the thyristor 8 is in a conductive state, this current flows from the primary winding 2 of the generator coil to the transistor 5 of the short circuit control semiconductor circuit B. As a current, it flows through the diode 9 without being restricted in any way by the thyristor 8. That is, in this state, the reverse rotation prevention circuit A is in a short-circuited state with respect to the forward current I ₂ via the thyristor 8 and the diode 9. Therefore, from this point on, the circuit operates similarly to the circuit of a conventional ignition system without reverse rotation prevention circuit A, and when the short-circuit current _I2 reaches the set value _I0 , it is cut off by the operation of transistors 4 and 5, This will cause ignition. At this time, the thyristor 8 is kept in a conductive state by the holding current even after the cut-off time _t1 .

FIG. 5 shows the relationship between the currents I ₁ and I ₂ and the conductive state of the thyristor 8 in the above operation, and during the period T ₁ a part of the current I ₁ is
This is the period in which the thyristor 8 is triggered by shunting the gate/cathode circuit of
T ₂ is the period during which the thyristor 8 remains triggered by the discharge current of the capacitor 10, and
T ₃ is a period during which the thyristor 8 conducts due to the continuation of the discharge current of the capacitor 10 and the short circuit current I ₂ flows. In this way, the thyristor 8 is (T ₁ +T ₂
+T ₃ ).

Next, during the reverse rotation during the internal combustion period using the anti-reverse rotation ignition device according to the present invention, the electromotive force generated in the primary winding 2 of the generator coil causes currents I' ₁ , I' ₂ and I′ ₃ is about to flow. but,
The initial current I' ₁ is in the same direction as the conduction direction of the transistor 5, and is not shunted to the gate-cathode circuit of the thyristor 8, nor does it charge the capacitor 10, so the thyristor 8 is not conductive. This is blocked by thyristor 8. Also resistance 1
5, the current flows through the resistor 15, but the current value is limited and does not reach the set value _I0 , so the transistor 5 does not cut off the current _I'1 and no ignition occurs. The next current I' ₂ , similar to the current I ₁ in FIG. 3 when the period rotates in the normal direction, shunts the aforementioned shunt circuits of the anti-reverse rotation circuit A, so that the thyristor 8 is triggered and the capacitor 10 is also charged. Therefore, even when the end of the period of current I' ₂ approaches, the thyristor 8 is maintained in a conductive state by discharging the capacitor 10, so that when the next current I' ₃ flows and reaches the set value I ₀ , It is possible that the current I' ₃ is cut off by the transistors 4 and 5 and that the ignition operation takes place at the time t ₃ . However, as already mentioned, the anti-reverse rotation ignition device of the present invention focuses on the difference in the height of the positive and negative electromotive force waveforms of the primary winding 2 of the generator coil, and therefore, the magnitude of the current I' ₃ is By reducing the magnitude of the current I′ ₂ , it is possible to prevent the generation of an ignition spark at the time t ₃ or to weaken the spark energy. Also, the ignition timing for _t3 is later than the ignition timing required for period drive (or the ignition system can be set to be later), so
This ignition operation does not cause the period to rotate in reverse or to maintain it in reverse, causing no practical problems.

In the embodiment shown in FIG. 1, the diode 16 is connected in series with the series circuit of the diode 6 and the resistor 7, but the cathode of the diode 16 is connected to the point P in FIG. A similar effect can be obtained even if the series circuit of the resistor 7 and the resistor 7 is connected in a bypass manner. Any suitable configuration can be selected depending on the resistance value required for the resistor 7.

6 and 7 show an alternative circuit to the circuit portion _A1 of the thyristor 8 shown in FIG. Electromotive force in the opposite direction of the primary winding 2 of the generator coil (as shown in Fig. 2)
Depending on the magnitude of V ₁ , V ₃ ), a large capacity capacitor 10 may be required. In such a case, a configuration in which sensitive small-signal thyristors are connected in parallel between the anode and gate of one thyristor as shown in Figure 6, or a configuration in which sensitive small-signal thyristors are connected in parallel as shown in Figure 7 is recommended. By replacing the transistors with a configuration in which they are connected in parallel, the desired operation can be performed without using a large capacitance capacitor.

During the operation of the reverse rotation prevention circuit A, which is a characteristic electric circuit of the device of the present invention, when the rotational speed of the internal combustion engine fluctuates, the induced electromotive force in the primary winding 2 of the generator coil also increases and decreases as the rotational speed increases and decreases. For this reason, the charging time of the capacitor 10 in the anti-reverse rotation circuit A decreases inversely with the increase in the rotational speed of the internal combustion engine, but the values of the capacitor 10 and the resistors 12 and 13 must be selected appropriately. Therefore, within the range of the frequency of the induced electromotive force of the generator coil primary winding 2 and its changes with respect to the normally used rotational speed of the internal combustion engine and its fluctuations, the capacitor 1
It has been confirmed through experiments by the inventors of the present invention that the battery 0 is charged to almost the same voltage value, and that the repeated charging and discharging operations are performed smoothly, and that the ignition operation of the internal combustion engine can be performed without any abnormality.

In the explanation of the embodiment of the present invention described above,
The polarity of the electromotive force waveform of the primary winding 2 of the generator coil is as illustrated in Figures 2 to 5, and therefore the directional elements in Figure 1 are connected in accordance with this, but the polarity is not limited to this. The present invention can be similarly applied even when the polarity of the electromotive force waveform is reversed and the connection of the directional element is changed accordingly.

In the present invention, as mentioned above, when the engine is rotating in reverse, the short circuit current due to the undesirable positive electromotive force that occurs at the beginning of each cycle of engine rotation is prevented from flowing and causing ignition. , it is detected whether or not a negative electromotive force is generated immediately before a positive electromotive force by checking whether or not the capacitor 10 of the reverse rotation prevention circuit A is charged, and only when this detection occurs, the thyristor 8 can be made conductive. I try to keep it in good condition. Therefore, when the engine is rotating in the normal direction in which a negative electromotive force is generated immediately before a positive electromotive force is generated, the thyristor 8 is turned on, and the short-circuit control semiconductor circuit B controls the short-circuit current as in the conventional ignition device. Detection and blocking are performed without any problems. On the other hand, when the engine rotates in reverse, a positive electromotive force is first generated, so the short-circuit current at that time is blocked by the non-conducting state of the thyristor 8.
This will not cause ignition. Thus,
According to the device of the present invention, an excellent effect can be obtained in that reverse rotation operation of the engine can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an ignition device according to an embodiment of the present invention. 2 to 5 are waveform diagrams of electromotive force or current for explaining the ignition operation of the conventional ignition device and the ignition device of the present invention. 6th
7 and 7 are circuit diagrams showing alternative circuits of essential parts of an ignition device according to another embodiment of the present invention. Explanation of symbols: 1...Permanent magnet rotor, 2...Generating coil, 5...Transistor (switching element), 8...Thyristor, 10...Capacitor,
A... Reverse rotation prevention circuit, B... Short circuit control semiconductor circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A magnet generator having a permanent magnet rotor driven by an internal combustion engine has a specific ignition timing induced in the primary winding of the generator coil and related to the desired ignition timing of the internal combustion engine. Among the electromotive force having voltage waveforms of one polarity before and after a voltage waveform of another polarity, the voltage of the voltage waveform of one specific polarity is short-circuited by a switching circuit, and then the primary voltage of the generator coil is short-circuited. An ignition device for an internal combustion engine that cuts off the short-circuit current when the short-circuit current flowing through the winding increases and reaches a set value to induce a high voltage in the secondary winding of the power-generating coil, the primary winding of the power-generating coil. a thyristor disposed in the path of the short-circuit current connecting the switching circuit and the switching circuit; a control circuit that detects the voltage of the voltage waveform of the other polarity generated by the thyristor and holds the thyristor in a conductive state only for a predetermined period after the detection; and a reverse rotation prevention circuit. Reverse rotation prevention ignition device for internal combustion engines. (2) The ignition device according to claim 1 of the utility model registration claim, wherein the thyristor is connected in a direction that allows the short circuit current to flow when the thyristor is conductive, and the control circuit is configured to control the electromotive force contained in the electromotive force. The reverse of the internal combustion engine, which includes a capacitor charged by a voltage of the other polarity voltage waveform, and maintains the thyristor in a conductive state by discharging the charge stored in the capacitor through a gate-cathode circuit of the thyristor. Anti-rotation ignition device.