CA2195793C - Ignition system for internal combustion engines - Google Patents
Ignition system for internal combustion engines Download PDFInfo
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- CA2195793C CA2195793C CA 2195793 CA2195793A CA2195793C CA 2195793 C CA2195793 C CA 2195793C CA 2195793 CA2195793 CA 2195793 CA 2195793 A CA2195793 A CA 2195793A CA 2195793 C CA2195793 C CA 2195793C
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Abstract
An ignition system for an internal combustion engine is disclosed. The ignition system includes an ignition capacitor having one end terminal connected to an anode of a thyristor of which a cathode is connected to an ignition coil, and an opposite end terminal of the ignition capacitor is connected to ground. Further, the cathode of a diode is connected to the anode of the thyristor, and the anode of the diode is connected to the cathode of the thyristor. With this configuration, charge and discharge of the capacitor for ignition are repeated with repeated inversion in polarity of an electric charge accumulated in the ignition capacitor. As a result, a spark discharge can be repeatedly achieved across the ignition plug and it is therefore possible to achieve a stable AC arc in accordance with the DC-CDI method.
Description
IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES
BACKGROUND OF THE INVENTION
The present invention relates to an ignition system for internal combustion engines.
Heretofore, ignition systems for internal combustion engines which supply high voltage to an ignition plug of an internal combustion engine, have included an ignition system of the type (AC-CDI method)in which a high voltage generated by a magneto-generator is accumulated in an ignition capacitor and the accumulated high voltage charge is discharged to an ignition plug to induce sparking at predetermined times in accordance with a crankshaft rotation position signal. This type of ignition system in which spark discharge is developed with an alternating current based on resonance between the ignition capacitor and inductance of the ignition coil is called AC arc type.
There is also another known type (DC-CDI method) of ignition system in which a capacitor is charged from a battery. An example of an ignition system of this type, a self-excited, contactless ignition system for an internal combustion engine, is disclosed in Japanese Unexamined Patent Publication No. 3-85370.
In the self-excited, contactless ignition system, a high voltage which has been stepped up by a DC step-up circuit is input in several stages to a main discharge capacitor, and at a predetermined time in the ignition cycle an SCR gate is triggered with a signal generated in a timing sensor, thereby permitting the electric charge accumulated in the main discharge capacitor to be discharged to an ignition coil to produce a single ignition spark. This type of spark discharge is called the DC arc type.
However, because the ignition system disclosed in the Japanese Unexamined Patent Publication No. 3-85370 is of the DC arc type, the spark discharge developed in the ignition coil occurs only once, so the discharge time is short and it is at times difficult to effect a satisfactory ignition of the air-fuel mixture in the engine.
One solution to the above-described problem may be to dispose a diode in parallel with the SCR in a direction opposite in polarity to the SCR to provide an AC arc discharge circuit, instead of a free-wheeling diode connected in parallel with a primary winding of the ignition coil. In this case, a series LC circuit comprising an ignition capacitor and the ignition coil is formed, thereby facilitating oscillation.
When this series LC circuit oscillates, the oscillation energy laps through the SCR and the DC-DC converter, so that a stable discharge of the ignition capacitor is obstructed and a spiky noise-containing discharge waveform (Fig. 4) results.
This gives rise to a new problem in which the voltage to which the ignition capacitor is charged does not reach a predetermined optimum level (150v).
Moreover, in the method described above wherein the DC-CDI type circuit is merely converted into an AC arc discharge circuit, since the free-wheeling diode is not used, there is also a problem because the electric current for charging the ignition capacitor flows through the ignition coil and hence the mere supply of electric current to the ignition circuit results in a high voltage accumulation in the secondary side of the ignition coil.
Another ignition system has been disclosed in Japanese Patent Publication No.48-12013. However, this ignition system has the disadvantage that to much high voltage is applied to the ignition coil during the charging of the ignition capacitor before the SCR turns on. This accelerates deterioration of the ignition coil.
SUMMARY OF THE INVENTION
The present invention provides an ignition system capable of generating a stable AC arc in accordance with the DC-CDI
method and of preventing high voltage from being applied to an ignition coil while charging of an ignition capacitor before turning on a thyristor to discharge the capictor. According to the present invention, a switching device is connected at one end to a capacitor and at the opposite end to a high voltage side of a primary coil of the ignition coil, and a reverse ON
circuit is connected in parallel with the switching device.
Preferably, the reverse ON circuit includes a diode, and the switching device includes a thyristor.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects, features and advantages of the present invention will become more apparent from the following ..~...w. . .~..,..~,_..~...~...._. _~_w.._.~....._.._.w..._. ._ ., _....____.
""~~'..~ -.
detailed description when read in conjunction with the accompanying drawings, in which:
Fig. 1 is a circuit diagram of an ignition system for internal combustion engines according to an embodiment of the present invention;
Fig. 2 is a diagram which shows the characteristics of voltages applied to a gate of a thyristor and to an ignition capacitor represented in relation to a crankshaft rotation position signal;
Fig. 3 is a diagram representing changes over time of a primary voltage on an ignition coil of an ignition system of this embodiment; and Fig. 4 is a diagram representing changes over time of a primary voltage of an ignition coil of a conventional ignition system.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
An embodiment of the present invention will be described hereinunder with reference to an example ignition system for two-wheeled motorcycles. It should be understood that the principles described can be applied to an ignition system for any internal combustion engine.
As shown in Fig. 1, the ignition system is of the DC-CDI
type and comprises an ignition circuit 10, a DC-DC
converter 20, an ignition timing control circuit 32 and a voltage detecting circuit 36. A DC voltage supplied from a battery 1 as a DC power supply is switched on or off by a switch 2. The DC-DC converter 20 serves as a step-up circuit which receives the DC voltage supplied from the battery 1 as an input voltage. In the DC-DC converter 20, the input voltage is stepped up to a DC voltage of several hundred volts by means of a transformer 21, a switching transistor 23 and a current detecting circuit 24. The DC voltage thus stepped up by the DC-DC converter 20 is used as a power supply for ignition in the ignition circuit 10, in which circuit the DC
voltage is further stepped up by an ignition coil 15 to a spark-dischargeable level. The stepped-up high voltage is supplied to an ignition plug 16.
The DC-DC converter 20 includes the transformer 21, a diode 22, the switching transistor 23, the current detecting circuit 24 and a Zener diode 25. An input end of a primary coil 21a in the transformer 21 is connected to the collector of the switching transistor 23, and the emitter is connected to ground through the current detecting circuit 24. A
terminal end of the primary coil 21a is connected to the cathode of a diode 31 whose anode is connected to the switch 2. Thus, an electric current is supplied to the primary coil 21a of the transformer 21 by the switching transistor 23 which is controlled by the value of a voltage applied to the base thereof. The current (primary current) flowing through the primary coil 21a is detected by the current detecting circuit 24. When the primary current has reached a predetermined current value, the current detecting circuit 24 turns off the switching transistor 23.
An input end of a tertiary coil 21c in the transformer 21 is connected to a terminal end of a secondary coil 21b in the transformer 21. The terminal end of the secondary coil 21b is . 2195793 also connected to ground. A terminal end of the tertiary coil 21c is connected through a resistor to the base of the switching transistor 23, so that an electric current generated in the tertiary coil 21c when current is applied to the primary coil is fed back to the base of the switching transistor 23. Consequently, when the primary current is applied, an electric current is induced in the tertiary coil 21c of the transformer 21 in a direction that increases the base current on the switching transistor 23. When this current reachs a predetermined value, the base current is connected to ground by the current detecting circuit 24, so that the switching transistor 23 is turned off.
When the switching transistor 23 is turned off, the voltage developed in the tertiary coil 21c also reverses in polarity and the base current flows to ground through the tertiary coil 21c, so that the switching transistor 23 turns off rapidly. As a result, electromagnetic energy induced by the primary current is transferred from the secondary coil 21b through a diode 22 to an ignition capacitor 12.
When the transfer of the electromagnetic energy is complete, the primary current begins to flow again in the primary coil 21a and the events described above are repeated until the charge voltage of the ignition capacitor 12 reaches a predetermined level. In this way oscillation of the DC-DC
converter 20 is accomplished and a stepped-up AC voltage is produced. This AC voltage is rectified by the diode 22 connected to an end of the secondary coil 21b in the transformer 21, whereby the stepped-up and rectified DC
_ , ' 21~5~93 voltage is accumulated in the ignition capacitor 12. The Zener diode 25 is connected between the base and the collector of the switching transistor 23 to protect the switching transistor 23.
The electric circuit for supplying the electric current from the DC-DC converter 20 to the ignition capacitor 12 via diode 22 forms a first closed circuit.
An oscillation stop circuit 27 is connected to the base of the switching transistor 23 and receives a voltage detection signal from the voltage detection circuit 36 which detects both output voltage of the DC-DC converter 20 and charge voltage of the ignition capacitor 12. The oscillation stop circuit 27 controls the base of the switching transistor 23 so as to stop oscillation of the DC-DC converter 20 when the charge voltage of the ignition capacitor 12 reaches a predetermined level. In this way the oscillation of the DC-DC
converter 20 is controlled.
The ignition circuit 10 includes the ignition capacitor 12, thyristor 13, diode 14, ignition coil 15 and ignition plug 16.
One end terminal of the ignition capacitor 12 is connected to an output terminal of the DC-DC converter 20, while an opposite end terminal of the capacitor 12 is connected to ground. Thus, the ignition capacitor 12 is connected between the output terminal of the DC-DC converter 20 and ground, whereby the DC voltage stepped up by the DC-DC
converter 20 is accumulated in the ignition capacitor 12. In order that the electric charge accumulated in the ignition ~219579~
capacitor 12 may be discharged to ground via a primary coil 15a of the ignition coil 15 at a predetermined time, a thyristor (SCR) 13 is used as a switching device. The thyristor 13 is connected in a forward direction between the ignition capacitor 12 and the ignition coil 15. That is, the anode serves as an input terminal of the thyristor 13 and is connected to one end terminal of the ignition capacitor 12, while the cathode services as an output terminal of the thyristor 13 and is connected to primary coil 15a of the ignition coil 15.
In parallel with the thyristor 13 and in a direction opposite in polarity to the thyristor there is connected the diode 14 which acts as a reverse ON circuit. More specifically, the anode of the thyristor 13 is connected to the cathode of the diode 14, while to the cathode of the thyristor 13 is connected to the anode of the diode 14. An ignition signal generated by the ignition timing control circuit 32 is input to the gate of the thyristor 13 via a diode 33 and a resistor 34. The ignition signal switches the thyristor 13 between an ON state in which the anode side and the cathode side of the thyristor 13 are electrically connected at a low resistance and an OFF state in which the anode and the cathode are electrically disconnected.
The cathode of the thyristor 13 and the anode of the diode 14 are connected to the primary coil 15a of the ignition coil 15, while a secondary coil 15b of the ignition coil 15 is connected to one end of the ignition plug 16. The opposite end side of the ignition plug 16 is connected to ground. In this arrangement, when a predetermined voltage is applied to the gate of the thyristor 13 by the ignition signal output from the ignition timing control circuit 32, the thyristor 13 turns ON, so that the electric charge accumulated in the ignition capacitor 12 flows to ground via the thyristor 13 and the primary coil 15a of the ignition coil 15. That is, a high voltage is induced in the secondary coil 15b of the ignition coil 15 as the electric current flows through the primary coil 15a of the ignition coil 15, which high voltage is applied to the gap in the ignition plug 16, so that a spark discharge occurs across the plug 16.
Once the electric current flowing through the primary coil 15a of the ignition coil 15 exceeds a predetermined peak, a voltage having an inverted polarity, namely, an electromotive force created by self-induction, is generated in the primary coil 15a. This voltage having the opposite polarity is charged to the ignition capacitor 12 through the ground connection. The electric charge thus accumulated in the capacitor 12 has a polarity opposite to the polarity of the electric charge supplied by the DC-DC converter 20. Since the diode 14 is connected in parallel with the thyristor 13 and in a direction opposite to the forward direction of the thyristor 13, the electric charge accumulated in the ignition capacitor 12 is permitted to flow to a lower potential successively through the ignition plug 16, ignition coil 15 and diode 14, that is, to one end of the capacitor 12.
Consequently, after an initial spark discharge by the ignition plug 16 using the electric charge stored in the capacitor 12 - ~ 2195793 by the DC-DC converter 20, a second spark discharge by the ignition plug 16 can occur using the electric charge of the electromotive force generated by self-induction in the primary coil 15a.
When the electric current flowing in the primary coil 15a at the instant of the second spark discharge exceeds a predetermined peak, a voltage having a further inverted polarity is generated in the coil 15a, so that the ignition capacitor 12 is charged and the electric charge accumulated therein flows to ground along the same path as the electric charge accumulated in the capacitor 12 by the DC-DC converter 20, whereby a third spark discharge by the ignition plug 16 can occur. Thus, in the primary coil 15a of the ignition coil 15, an electric current flows which gradually attenuates while alternating its direction of flow. Consequently, as a primary voltage Vout shown in Fig. 3 occurs in the primary coil 15a, a secondary voltage stepped up in proportion to the primary voltage Vout is induced in the secondary coil 15b. As a result, a plurality of spark discharges occur across the gap of the ignition plug 16 and an AC arc is achieved.
The electric circuit for conducting an electric current from the ignition capacitor 12 to the ignition coil 15 via the thyristor 13 and from the ignition coil 15 to the capacitor 12 via diode 14 forms second closed circuit.
The ignition timing control circuit 32 controls the ignition timing of the ignition plug 16 in accordance with the crankshaft rotation position signal provided by a timing sensor 5. More specifically, the timing sensor 5 detects a 2i93~93 rotation position of a crankshaft of the engine (not shown) on the basis of the position of a magnet on a flywheel attached to the crankshaft, and in accordance with a signal provided by the timing sensor 5 the ignition timing control circuit 32 outputs an OFF signal to the oscillation stop circuit 27 for the DC-DC converter 20 and an ignition signal to the gate of the thyristor 13 in the ignition circuit 10, each at a predetermined time. Using those signals the control circuit 32 controls the DC-DC converter 20 and the ignition circuit 10 as will be described below. The diode 33 connected between the ignition timing control circuit 32 and the gate of the thyristor 13 is a protective diode for preventing the high voltage applied to the ignition coil 15 from flowing to the ignition timing control circuit 32. Further, a diode 35, which is connected in parallel between the ignition timing control circuit 32 and ground, is a protective diode for the control circuit 32.
More detailed operation of the ignition system according to this embodiment will be described with reference to the diagram of Fig. 2. The characteristics shown in FIG. 2 were obtained using an oscilloscope to plot changes over time of a gate voltage VSG of the thyristor 13 and a terminal voltage VC
of the ignition capacitor 12. Those changes are expressed in relation to changes over time of the crankshaft rotation position signal. As to the measurement ranges used on the oscilloscope in the measurement of the gate voltage VSG and the terminal voltage VC, the axis of abscissa, or voltage axis, is set to 2V/div for VSG and 50V/div for VC, and the axis of ordinate, or time base, is set to 1 ms/div for both VSG and VC.
As shown in Fig. 2, when the crankshaft rotation position signal output by the timing sensor 5 deflects to the positive side, an ignition signal is output from the ignition timing control circuit 32 to the gate of the thyristor 13 as indicated by an upward arrow at the leading edge of the crankshaft rotation position signal. As a result, the gate voltage of the thyristor 13 which is normally OFF, with a positive voltage applied to the anode side and a negative voltage applied to the cathode side by the electric charge accumulated in the ignition capacitor 12, is driven high.
Consequently, the thyristor 13 is switched from OFF to ON, and the anode and cathode of the thyristor 13 assume an electrically conductive state at a low resistance so that the electric charge stored in the ignition capacitor 12 is conducted to the primary coil 15a of the ignition coil 15 via the thyristor 13. By this conduction of electric charge, namely, by the electric current flowing through the primary coil 15a, a predetermined high voltage is induced in the secondary coil 15b of the ignition coil 15 and hence a spark discharge occurs across the gap of the ignition plug 16.
Once the electric current flowing through the primary coil 15a of the ignition coil 15, i.e., the primary current, exceeds a predetermined peak, the voltage developed across the primary coil 15a reverses polarity and is accumulated in the ignition capacitor 12 as an electric charge having an opposite polarity. This electric charge of opposite polarity '219~79~
accumulated in the capacitor 12 is discharged via diode 14, so that a second spark discharge occurs across the ignition plug 16. Further, when the primary current in the ignition coil 15 exceeds a predetermined peak due to the electric charge of opposite polarity, the ignition capacitor 12 accumulates a third electric charge having the same polarity as that of the electric charge stored by the DC-DC
converter 20. Since the thyristor 13 is held ON, the electric charge accumulated in the ignition capacitor 12 is once more discharged via the thyristor 13 and a spark discharge occurs across the ignition plug 16. In this way the cycle of charge and discharge of the capacitor 12 is repeated as is the inversion in polarity of the electric charge accumulated therein, whereby a spark discharge can be generated repeatedly across the ignition plug 16. Thus, it is possible to achieve a stable DC arc in accordance with the DC-CDI method.
As shown in Fig. 2, the terminal voltage VC of the ignition capacitor 12 oscillates alternate-currentwise, and after a period tl from the start of discharge, it drops to nearly zero volts. The period tl corresponds to the spark discharge time of the ignition plug 16. In Fig. 2 it is shown that both the gate voltage VSG of the thyristor l3 and the terminal voltage VC of the ignition capacitor 12 attenuate while oscillating substantially in an alternate-currentwise mode during the period tl. The period t2 shown in the same figure indicates the period during which the voltage based on the ignition signal is applied to the gate of the thyristor 13 .
' 219~~~~
At the leading edge of the crankshaft rotation position signal referred to previously, the ignition timing control circuit 32 outputs not only an ignition signal to the gate of the thyristor 13 but also a HALT signal for the DC-DC
converter 20 to the oscillation stop circuit 27. Upon receipt of the HALT signal the oscillation stop circuit 27 controls the base of the switching transistor 23 to stop the oscillation of the DC-DC converter 20. Consequently, a stepped-up voltage is not induced in the secondary coil 21b of the transformer 21 and the DC-DC converter 20 turns off. The quiescent period of the DC-DC converter 20 is represented by t3. The period t3 is determined by a timer circuit which includes a resistor and a capacitor, which are the preferred components of the oscillation stop circuit 27. More specifically, upon output of the HALT signal from the ignition timing control circuit 32, the timer circuit is initialized and the base of the switching transistor 23 is controlled by the oscillation stop circuit 27 until predetermined time t3 has elapsed. The quiescent period t3 has the following relation to the discharge period tl and the thyristor 13 ON
period t2 . tl < t2 < t3 Upon lapse of the quiescent period t3, control by the oscillation stop circuit 27 is terminated, so that the oscillation of the DC-DC converter 20 is resumed and a stepped-up voltage is induced on the output side of the DC-DC
converter. Then, as shown in Fig. 2, the stepped-up voltage is accumulated little by little in the ignition capacitor 12 and this charging continues until the voltage detected by the voltage detecting circuit 36 reaches the predetermined level.
More specifically, the voltage detecting circuit 36 monitors the terminal voltage VC of the ignition capacitor 12 and, when VC has reached the predetermined level, the voltage control circuit outputs a HALT signal to the oscillation stop circuit 27. Upon receipt of the HALT signal the oscillation stop circuit 27 controls the base of the switching transistor 23 which stops the oscillation of the DC-DC converter 20 in the same way as when a HALT signal is received from the ignition timing control circuit 32. As a result, the oscillation of the DC-DC converter 20 is stopped and therefore the stepped-up voltage in the transformer 21 is no longer output by the DC-DC converter 20. However, between the secondary coil 21b of the transformer 21 and the ignition capacitor 12, the diode 22 is connected in the forward direction from the transformer 21 toward the ignition capacitor 12, so that the electric charge stored in the ignition capacitor 12 is prevented from flowing back to the transformer 21. Thus, the electric charge accumulated in the capacitor 12 is stored until the thyristor 13 is switched from OFF to ON.
In Fig. 2, the period from the foregoing restart of oscillation of the DC-DC converter 20 until stopping the oscillation by the voltage detecting circuit 36 is represented by t4. It is seen that during the charge period t4, the terminal voltage VC of the ignition capacitor 12 rises gradually.
If the voltage supply from the DC-DC converter 20 is cut off after the terminal voltage VC of the ignition capacitor 12 has reached the predetermined level, the capacitor 12 stores the charge until arrival the next ignition timing pulse. The charge storage period of the capacitor 12 is represented by the period t5 in Fig. 2. After the crankshaft (not shown) rotates 360° CA from the previous ignition time, the crankshaft rotation position signal deflects in the positive direction and a high signal is generated, whereby an ignition signal is output by the ignition timing control circuit 32 to the thyristor 13 in the ignition circuit 10. At the same time, a _H_AT~T signal is output by the ignition timing control circuit 32 to the oscillation OFF circuit 27. As a result, the thyristor 13 is switched from OFF to ON and the oscillation of the DC-DC converter 20 stops, as described above.
Consequently, the electric charge accumulated and stored in the ignition capacitor 12 escapes to the ground side of the primary coil 15a of the ignition coil 15, thus inducing a spark discharge across the ignition plug 16.
According to this embodiment, as set forth above, one end terminal of the ignition capacitor 12 is connected to the anode of the thyristor 13 whose cathode is connected to the ignition coil 15, and its opposite end terminal is connected to ground. Further, the cathode of the diode 14 is connected to the anode of the thyristor 13, and the anode of the diode 14 is connected to the cathode of the thyristor 13. With this construction, the charge and discharge of the ignition capacitor 12 is repeated with a repeating inversion in polarity of the electric charge accumulated in the capacitor . 21~~~~3 12. Thus, a spark discharge across the ignition plug 16 can be repeatedly achieved. It is therefore possible to achieve a stable AC arc in accordance with the DC-CDI method.
Accordingly, it is possible to achieve a long sparking period by an AC arc whose attainment by the DC-CDI method has heretofore been difficult.
In this embodiment, moreover, the first closed circuit in which the ignition capacitor 12 is charged by both DC-DC
converter 20 and the diode 22, and the second closed circuit in which an electric charge shifts between the ignition capacitor 12 and the ignition coil 15 so as to induce repeated charges and discharges of the capacitor 12 through both the SCR 13 and the diode 14, are separated from each other, so that a series LC circuit comprising the capacitor 12 and the ignition coil 15 is not formed.
Therefore, the charging of the capacitor 12 by the DC-DC
converter 20 can be effected stably up to a predetermined voltage level.
Further, according to this embodiment, the opposite end terminal of the ignition capacitor 12 is connected to ground, so when an electric charge is not stored in the capacitor 12, the output voltage of the DC-DC converter 20 developed by on-off operation of the switch 2 does cause a flow of electric current in the ignition coil 15 unless an ignition signal is fed to the gate of the thyristor 13.
For example in Fig. 1, an AC arc as described above can be obtained even in a circuit configuration wherein the position of connection of the parallel thyristor 13 and diode ~19~7~~
~14 with the series-connected ignition coil 15 and ignition plug 16 is transposed. However, this circuit configuration has two problems:
(1) Since the capacitor for ignition and the ignition coil are electrically interconnected at all times, the ignition coil is supplied a voltage as high as several hundred volts from the ignition capacitor over a longer period of time than in the circuit configuration adopted in the above embodiment, and as a result deterioration in electrical insulation characteristics of the ignition coil is accelerated.
(2) Since the juncture between the primary coil and the secondary coil is not connected to ground but is connected to the parallel circuit of the thyristor and the diode, it is necessary to provide a new terminal for connection to the parallel thyristor-diode circuit, that is, a condutor for connection to the terminal is also required, which increases the number of components and the production cost.
These problems can be avoided by adopting the circuit configuration of the embodiment shown in Fig. 1.
Additionally, according to this embodiment it is possible to prevent a high voltage from being applied to the ignition coil before turning on the thyristor.
BACKGROUND OF THE INVENTION
The present invention relates to an ignition system for internal combustion engines.
Heretofore, ignition systems for internal combustion engines which supply high voltage to an ignition plug of an internal combustion engine, have included an ignition system of the type (AC-CDI method)in which a high voltage generated by a magneto-generator is accumulated in an ignition capacitor and the accumulated high voltage charge is discharged to an ignition plug to induce sparking at predetermined times in accordance with a crankshaft rotation position signal. This type of ignition system in which spark discharge is developed with an alternating current based on resonance between the ignition capacitor and inductance of the ignition coil is called AC arc type.
There is also another known type (DC-CDI method) of ignition system in which a capacitor is charged from a battery. An example of an ignition system of this type, a self-excited, contactless ignition system for an internal combustion engine, is disclosed in Japanese Unexamined Patent Publication No. 3-85370.
In the self-excited, contactless ignition system, a high voltage which has been stepped up by a DC step-up circuit is input in several stages to a main discharge capacitor, and at a predetermined time in the ignition cycle an SCR gate is triggered with a signal generated in a timing sensor, thereby permitting the electric charge accumulated in the main discharge capacitor to be discharged to an ignition coil to produce a single ignition spark. This type of spark discharge is called the DC arc type.
However, because the ignition system disclosed in the Japanese Unexamined Patent Publication No. 3-85370 is of the DC arc type, the spark discharge developed in the ignition coil occurs only once, so the discharge time is short and it is at times difficult to effect a satisfactory ignition of the air-fuel mixture in the engine.
One solution to the above-described problem may be to dispose a diode in parallel with the SCR in a direction opposite in polarity to the SCR to provide an AC arc discharge circuit, instead of a free-wheeling diode connected in parallel with a primary winding of the ignition coil. In this case, a series LC circuit comprising an ignition capacitor and the ignition coil is formed, thereby facilitating oscillation.
When this series LC circuit oscillates, the oscillation energy laps through the SCR and the DC-DC converter, so that a stable discharge of the ignition capacitor is obstructed and a spiky noise-containing discharge waveform (Fig. 4) results.
This gives rise to a new problem in which the voltage to which the ignition capacitor is charged does not reach a predetermined optimum level (150v).
Moreover, in the method described above wherein the DC-CDI type circuit is merely converted into an AC arc discharge circuit, since the free-wheeling diode is not used, there is also a problem because the electric current for charging the ignition capacitor flows through the ignition coil and hence the mere supply of electric current to the ignition circuit results in a high voltage accumulation in the secondary side of the ignition coil.
Another ignition system has been disclosed in Japanese Patent Publication No.48-12013. However, this ignition system has the disadvantage that to much high voltage is applied to the ignition coil during the charging of the ignition capacitor before the SCR turns on. This accelerates deterioration of the ignition coil.
SUMMARY OF THE INVENTION
The present invention provides an ignition system capable of generating a stable AC arc in accordance with the DC-CDI
method and of preventing high voltage from being applied to an ignition coil while charging of an ignition capacitor before turning on a thyristor to discharge the capictor. According to the present invention, a switching device is connected at one end to a capacitor and at the opposite end to a high voltage side of a primary coil of the ignition coil, and a reverse ON
circuit is connected in parallel with the switching device.
Preferably, the reverse ON circuit includes a diode, and the switching device includes a thyristor.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects, features and advantages of the present invention will become more apparent from the following ..~...w. . .~..,..~,_..~...~...._. _~_w.._.~....._.._.w..._. ._ ., _....____.
""~~'..~ -.
detailed description when read in conjunction with the accompanying drawings, in which:
Fig. 1 is a circuit diagram of an ignition system for internal combustion engines according to an embodiment of the present invention;
Fig. 2 is a diagram which shows the characteristics of voltages applied to a gate of a thyristor and to an ignition capacitor represented in relation to a crankshaft rotation position signal;
Fig. 3 is a diagram representing changes over time of a primary voltage on an ignition coil of an ignition system of this embodiment; and Fig. 4 is a diagram representing changes over time of a primary voltage of an ignition coil of a conventional ignition system.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
An embodiment of the present invention will be described hereinunder with reference to an example ignition system for two-wheeled motorcycles. It should be understood that the principles described can be applied to an ignition system for any internal combustion engine.
As shown in Fig. 1, the ignition system is of the DC-CDI
type and comprises an ignition circuit 10, a DC-DC
converter 20, an ignition timing control circuit 32 and a voltage detecting circuit 36. A DC voltage supplied from a battery 1 as a DC power supply is switched on or off by a switch 2. The DC-DC converter 20 serves as a step-up circuit which receives the DC voltage supplied from the battery 1 as an input voltage. In the DC-DC converter 20, the input voltage is stepped up to a DC voltage of several hundred volts by means of a transformer 21, a switching transistor 23 and a current detecting circuit 24. The DC voltage thus stepped up by the DC-DC converter 20 is used as a power supply for ignition in the ignition circuit 10, in which circuit the DC
voltage is further stepped up by an ignition coil 15 to a spark-dischargeable level. The stepped-up high voltage is supplied to an ignition plug 16.
The DC-DC converter 20 includes the transformer 21, a diode 22, the switching transistor 23, the current detecting circuit 24 and a Zener diode 25. An input end of a primary coil 21a in the transformer 21 is connected to the collector of the switching transistor 23, and the emitter is connected to ground through the current detecting circuit 24. A
terminal end of the primary coil 21a is connected to the cathode of a diode 31 whose anode is connected to the switch 2. Thus, an electric current is supplied to the primary coil 21a of the transformer 21 by the switching transistor 23 which is controlled by the value of a voltage applied to the base thereof. The current (primary current) flowing through the primary coil 21a is detected by the current detecting circuit 24. When the primary current has reached a predetermined current value, the current detecting circuit 24 turns off the switching transistor 23.
An input end of a tertiary coil 21c in the transformer 21 is connected to a terminal end of a secondary coil 21b in the transformer 21. The terminal end of the secondary coil 21b is . 2195793 also connected to ground. A terminal end of the tertiary coil 21c is connected through a resistor to the base of the switching transistor 23, so that an electric current generated in the tertiary coil 21c when current is applied to the primary coil is fed back to the base of the switching transistor 23. Consequently, when the primary current is applied, an electric current is induced in the tertiary coil 21c of the transformer 21 in a direction that increases the base current on the switching transistor 23. When this current reachs a predetermined value, the base current is connected to ground by the current detecting circuit 24, so that the switching transistor 23 is turned off.
When the switching transistor 23 is turned off, the voltage developed in the tertiary coil 21c also reverses in polarity and the base current flows to ground through the tertiary coil 21c, so that the switching transistor 23 turns off rapidly. As a result, electromagnetic energy induced by the primary current is transferred from the secondary coil 21b through a diode 22 to an ignition capacitor 12.
When the transfer of the electromagnetic energy is complete, the primary current begins to flow again in the primary coil 21a and the events described above are repeated until the charge voltage of the ignition capacitor 12 reaches a predetermined level. In this way oscillation of the DC-DC
converter 20 is accomplished and a stepped-up AC voltage is produced. This AC voltage is rectified by the diode 22 connected to an end of the secondary coil 21b in the transformer 21, whereby the stepped-up and rectified DC
_ , ' 21~5~93 voltage is accumulated in the ignition capacitor 12. The Zener diode 25 is connected between the base and the collector of the switching transistor 23 to protect the switching transistor 23.
The electric circuit for supplying the electric current from the DC-DC converter 20 to the ignition capacitor 12 via diode 22 forms a first closed circuit.
An oscillation stop circuit 27 is connected to the base of the switching transistor 23 and receives a voltage detection signal from the voltage detection circuit 36 which detects both output voltage of the DC-DC converter 20 and charge voltage of the ignition capacitor 12. The oscillation stop circuit 27 controls the base of the switching transistor 23 so as to stop oscillation of the DC-DC converter 20 when the charge voltage of the ignition capacitor 12 reaches a predetermined level. In this way the oscillation of the DC-DC
converter 20 is controlled.
The ignition circuit 10 includes the ignition capacitor 12, thyristor 13, diode 14, ignition coil 15 and ignition plug 16.
One end terminal of the ignition capacitor 12 is connected to an output terminal of the DC-DC converter 20, while an opposite end terminal of the capacitor 12 is connected to ground. Thus, the ignition capacitor 12 is connected between the output terminal of the DC-DC converter 20 and ground, whereby the DC voltage stepped up by the DC-DC
converter 20 is accumulated in the ignition capacitor 12. In order that the electric charge accumulated in the ignition ~219579~
capacitor 12 may be discharged to ground via a primary coil 15a of the ignition coil 15 at a predetermined time, a thyristor (SCR) 13 is used as a switching device. The thyristor 13 is connected in a forward direction between the ignition capacitor 12 and the ignition coil 15. That is, the anode serves as an input terminal of the thyristor 13 and is connected to one end terminal of the ignition capacitor 12, while the cathode services as an output terminal of the thyristor 13 and is connected to primary coil 15a of the ignition coil 15.
In parallel with the thyristor 13 and in a direction opposite in polarity to the thyristor there is connected the diode 14 which acts as a reverse ON circuit. More specifically, the anode of the thyristor 13 is connected to the cathode of the diode 14, while to the cathode of the thyristor 13 is connected to the anode of the diode 14. An ignition signal generated by the ignition timing control circuit 32 is input to the gate of the thyristor 13 via a diode 33 and a resistor 34. The ignition signal switches the thyristor 13 between an ON state in which the anode side and the cathode side of the thyristor 13 are electrically connected at a low resistance and an OFF state in which the anode and the cathode are electrically disconnected.
The cathode of the thyristor 13 and the anode of the diode 14 are connected to the primary coil 15a of the ignition coil 15, while a secondary coil 15b of the ignition coil 15 is connected to one end of the ignition plug 16. The opposite end side of the ignition plug 16 is connected to ground. In this arrangement, when a predetermined voltage is applied to the gate of the thyristor 13 by the ignition signal output from the ignition timing control circuit 32, the thyristor 13 turns ON, so that the electric charge accumulated in the ignition capacitor 12 flows to ground via the thyristor 13 and the primary coil 15a of the ignition coil 15. That is, a high voltage is induced in the secondary coil 15b of the ignition coil 15 as the electric current flows through the primary coil 15a of the ignition coil 15, which high voltage is applied to the gap in the ignition plug 16, so that a spark discharge occurs across the plug 16.
Once the electric current flowing through the primary coil 15a of the ignition coil 15 exceeds a predetermined peak, a voltage having an inverted polarity, namely, an electromotive force created by self-induction, is generated in the primary coil 15a. This voltage having the opposite polarity is charged to the ignition capacitor 12 through the ground connection. The electric charge thus accumulated in the capacitor 12 has a polarity opposite to the polarity of the electric charge supplied by the DC-DC converter 20. Since the diode 14 is connected in parallel with the thyristor 13 and in a direction opposite to the forward direction of the thyristor 13, the electric charge accumulated in the ignition capacitor 12 is permitted to flow to a lower potential successively through the ignition plug 16, ignition coil 15 and diode 14, that is, to one end of the capacitor 12.
Consequently, after an initial spark discharge by the ignition plug 16 using the electric charge stored in the capacitor 12 - ~ 2195793 by the DC-DC converter 20, a second spark discharge by the ignition plug 16 can occur using the electric charge of the electromotive force generated by self-induction in the primary coil 15a.
When the electric current flowing in the primary coil 15a at the instant of the second spark discharge exceeds a predetermined peak, a voltage having a further inverted polarity is generated in the coil 15a, so that the ignition capacitor 12 is charged and the electric charge accumulated therein flows to ground along the same path as the electric charge accumulated in the capacitor 12 by the DC-DC converter 20, whereby a third spark discharge by the ignition plug 16 can occur. Thus, in the primary coil 15a of the ignition coil 15, an electric current flows which gradually attenuates while alternating its direction of flow. Consequently, as a primary voltage Vout shown in Fig. 3 occurs in the primary coil 15a, a secondary voltage stepped up in proportion to the primary voltage Vout is induced in the secondary coil 15b. As a result, a plurality of spark discharges occur across the gap of the ignition plug 16 and an AC arc is achieved.
The electric circuit for conducting an electric current from the ignition capacitor 12 to the ignition coil 15 via the thyristor 13 and from the ignition coil 15 to the capacitor 12 via diode 14 forms second closed circuit.
The ignition timing control circuit 32 controls the ignition timing of the ignition plug 16 in accordance with the crankshaft rotation position signal provided by a timing sensor 5. More specifically, the timing sensor 5 detects a 2i93~93 rotation position of a crankshaft of the engine (not shown) on the basis of the position of a magnet on a flywheel attached to the crankshaft, and in accordance with a signal provided by the timing sensor 5 the ignition timing control circuit 32 outputs an OFF signal to the oscillation stop circuit 27 for the DC-DC converter 20 and an ignition signal to the gate of the thyristor 13 in the ignition circuit 10, each at a predetermined time. Using those signals the control circuit 32 controls the DC-DC converter 20 and the ignition circuit 10 as will be described below. The diode 33 connected between the ignition timing control circuit 32 and the gate of the thyristor 13 is a protective diode for preventing the high voltage applied to the ignition coil 15 from flowing to the ignition timing control circuit 32. Further, a diode 35, which is connected in parallel between the ignition timing control circuit 32 and ground, is a protective diode for the control circuit 32.
More detailed operation of the ignition system according to this embodiment will be described with reference to the diagram of Fig. 2. The characteristics shown in FIG. 2 were obtained using an oscilloscope to plot changes over time of a gate voltage VSG of the thyristor 13 and a terminal voltage VC
of the ignition capacitor 12. Those changes are expressed in relation to changes over time of the crankshaft rotation position signal. As to the measurement ranges used on the oscilloscope in the measurement of the gate voltage VSG and the terminal voltage VC, the axis of abscissa, or voltage axis, is set to 2V/div for VSG and 50V/div for VC, and the axis of ordinate, or time base, is set to 1 ms/div for both VSG and VC.
As shown in Fig. 2, when the crankshaft rotation position signal output by the timing sensor 5 deflects to the positive side, an ignition signal is output from the ignition timing control circuit 32 to the gate of the thyristor 13 as indicated by an upward arrow at the leading edge of the crankshaft rotation position signal. As a result, the gate voltage of the thyristor 13 which is normally OFF, with a positive voltage applied to the anode side and a negative voltage applied to the cathode side by the electric charge accumulated in the ignition capacitor 12, is driven high.
Consequently, the thyristor 13 is switched from OFF to ON, and the anode and cathode of the thyristor 13 assume an electrically conductive state at a low resistance so that the electric charge stored in the ignition capacitor 12 is conducted to the primary coil 15a of the ignition coil 15 via the thyristor 13. By this conduction of electric charge, namely, by the electric current flowing through the primary coil 15a, a predetermined high voltage is induced in the secondary coil 15b of the ignition coil 15 and hence a spark discharge occurs across the gap of the ignition plug 16.
Once the electric current flowing through the primary coil 15a of the ignition coil 15, i.e., the primary current, exceeds a predetermined peak, the voltage developed across the primary coil 15a reverses polarity and is accumulated in the ignition capacitor 12 as an electric charge having an opposite polarity. This electric charge of opposite polarity '219~79~
accumulated in the capacitor 12 is discharged via diode 14, so that a second spark discharge occurs across the ignition plug 16. Further, when the primary current in the ignition coil 15 exceeds a predetermined peak due to the electric charge of opposite polarity, the ignition capacitor 12 accumulates a third electric charge having the same polarity as that of the electric charge stored by the DC-DC
converter 20. Since the thyristor 13 is held ON, the electric charge accumulated in the ignition capacitor 12 is once more discharged via the thyristor 13 and a spark discharge occurs across the ignition plug 16. In this way the cycle of charge and discharge of the capacitor 12 is repeated as is the inversion in polarity of the electric charge accumulated therein, whereby a spark discharge can be generated repeatedly across the ignition plug 16. Thus, it is possible to achieve a stable DC arc in accordance with the DC-CDI method.
As shown in Fig. 2, the terminal voltage VC of the ignition capacitor 12 oscillates alternate-currentwise, and after a period tl from the start of discharge, it drops to nearly zero volts. The period tl corresponds to the spark discharge time of the ignition plug 16. In Fig. 2 it is shown that both the gate voltage VSG of the thyristor l3 and the terminal voltage VC of the ignition capacitor 12 attenuate while oscillating substantially in an alternate-currentwise mode during the period tl. The period t2 shown in the same figure indicates the period during which the voltage based on the ignition signal is applied to the gate of the thyristor 13 .
' 219~~~~
At the leading edge of the crankshaft rotation position signal referred to previously, the ignition timing control circuit 32 outputs not only an ignition signal to the gate of the thyristor 13 but also a HALT signal for the DC-DC
converter 20 to the oscillation stop circuit 27. Upon receipt of the HALT signal the oscillation stop circuit 27 controls the base of the switching transistor 23 to stop the oscillation of the DC-DC converter 20. Consequently, a stepped-up voltage is not induced in the secondary coil 21b of the transformer 21 and the DC-DC converter 20 turns off. The quiescent period of the DC-DC converter 20 is represented by t3. The period t3 is determined by a timer circuit which includes a resistor and a capacitor, which are the preferred components of the oscillation stop circuit 27. More specifically, upon output of the HALT signal from the ignition timing control circuit 32, the timer circuit is initialized and the base of the switching transistor 23 is controlled by the oscillation stop circuit 27 until predetermined time t3 has elapsed. The quiescent period t3 has the following relation to the discharge period tl and the thyristor 13 ON
period t2 . tl < t2 < t3 Upon lapse of the quiescent period t3, control by the oscillation stop circuit 27 is terminated, so that the oscillation of the DC-DC converter 20 is resumed and a stepped-up voltage is induced on the output side of the DC-DC
converter. Then, as shown in Fig. 2, the stepped-up voltage is accumulated little by little in the ignition capacitor 12 and this charging continues until the voltage detected by the voltage detecting circuit 36 reaches the predetermined level.
More specifically, the voltage detecting circuit 36 monitors the terminal voltage VC of the ignition capacitor 12 and, when VC has reached the predetermined level, the voltage control circuit outputs a HALT signal to the oscillation stop circuit 27. Upon receipt of the HALT signal the oscillation stop circuit 27 controls the base of the switching transistor 23 which stops the oscillation of the DC-DC converter 20 in the same way as when a HALT signal is received from the ignition timing control circuit 32. As a result, the oscillation of the DC-DC converter 20 is stopped and therefore the stepped-up voltage in the transformer 21 is no longer output by the DC-DC converter 20. However, between the secondary coil 21b of the transformer 21 and the ignition capacitor 12, the diode 22 is connected in the forward direction from the transformer 21 toward the ignition capacitor 12, so that the electric charge stored in the ignition capacitor 12 is prevented from flowing back to the transformer 21. Thus, the electric charge accumulated in the capacitor 12 is stored until the thyristor 13 is switched from OFF to ON.
In Fig. 2, the period from the foregoing restart of oscillation of the DC-DC converter 20 until stopping the oscillation by the voltage detecting circuit 36 is represented by t4. It is seen that during the charge period t4, the terminal voltage VC of the ignition capacitor 12 rises gradually.
If the voltage supply from the DC-DC converter 20 is cut off after the terminal voltage VC of the ignition capacitor 12 has reached the predetermined level, the capacitor 12 stores the charge until arrival the next ignition timing pulse. The charge storage period of the capacitor 12 is represented by the period t5 in Fig. 2. After the crankshaft (not shown) rotates 360° CA from the previous ignition time, the crankshaft rotation position signal deflects in the positive direction and a high signal is generated, whereby an ignition signal is output by the ignition timing control circuit 32 to the thyristor 13 in the ignition circuit 10. At the same time, a _H_AT~T signal is output by the ignition timing control circuit 32 to the oscillation OFF circuit 27. As a result, the thyristor 13 is switched from OFF to ON and the oscillation of the DC-DC converter 20 stops, as described above.
Consequently, the electric charge accumulated and stored in the ignition capacitor 12 escapes to the ground side of the primary coil 15a of the ignition coil 15, thus inducing a spark discharge across the ignition plug 16.
According to this embodiment, as set forth above, one end terminal of the ignition capacitor 12 is connected to the anode of the thyristor 13 whose cathode is connected to the ignition coil 15, and its opposite end terminal is connected to ground. Further, the cathode of the diode 14 is connected to the anode of the thyristor 13, and the anode of the diode 14 is connected to the cathode of the thyristor 13. With this construction, the charge and discharge of the ignition capacitor 12 is repeated with a repeating inversion in polarity of the electric charge accumulated in the capacitor . 21~~~~3 12. Thus, a spark discharge across the ignition plug 16 can be repeatedly achieved. It is therefore possible to achieve a stable AC arc in accordance with the DC-CDI method.
Accordingly, it is possible to achieve a long sparking period by an AC arc whose attainment by the DC-CDI method has heretofore been difficult.
In this embodiment, moreover, the first closed circuit in which the ignition capacitor 12 is charged by both DC-DC
converter 20 and the diode 22, and the second closed circuit in which an electric charge shifts between the ignition capacitor 12 and the ignition coil 15 so as to induce repeated charges and discharges of the capacitor 12 through both the SCR 13 and the diode 14, are separated from each other, so that a series LC circuit comprising the capacitor 12 and the ignition coil 15 is not formed.
Therefore, the charging of the capacitor 12 by the DC-DC
converter 20 can be effected stably up to a predetermined voltage level.
Further, according to this embodiment, the opposite end terminal of the ignition capacitor 12 is connected to ground, so when an electric charge is not stored in the capacitor 12, the output voltage of the DC-DC converter 20 developed by on-off operation of the switch 2 does cause a flow of electric current in the ignition coil 15 unless an ignition signal is fed to the gate of the thyristor 13.
For example in Fig. 1, an AC arc as described above can be obtained even in a circuit configuration wherein the position of connection of the parallel thyristor 13 and diode ~19~7~~
~14 with the series-connected ignition coil 15 and ignition plug 16 is transposed. However, this circuit configuration has two problems:
(1) Since the capacitor for ignition and the ignition coil are electrically interconnected at all times, the ignition coil is supplied a voltage as high as several hundred volts from the ignition capacitor over a longer period of time than in the circuit configuration adopted in the above embodiment, and as a result deterioration in electrical insulation characteristics of the ignition coil is accelerated.
(2) Since the juncture between the primary coil and the secondary coil is not connected to ground but is connected to the parallel circuit of the thyristor and the diode, it is necessary to provide a new terminal for connection to the parallel thyristor-diode circuit, that is, a condutor for connection to the terminal is also required, which increases the number of components and the production cost.
These problems can be avoided by adopting the circuit configuration of the embodiment shown in Fig. 1.
Additionally, according to this embodiment it is possible to prevent a high voltage from being applied to the ignition coil before turning on the thyristor.
Claims (3)
1. An ignition system for an internal combustion engine, comprising:
a voltage step-up circuit for stepping up a DC voltage;
a capacitor in which an output voltage of said step-up circuit is accumulated;
an ignition coil having a primary coil through which a primary current from said capacitor flows and a secondary coil in which a secondary voltage is induced by said primary current;
an ignition plug connected to said ignition coil for generating a spark discharge upon application thereto of said secondary voltage;
a switching device for permitting the flow of the primary current from said capacitor to said ignition coil at a predetermined time and blocking the flow of the primary current from the ignition coil to the capacitor; and a reverse ON circuit for permitting the flow of the primary current from said ignition coil to said capacitor and blocking the flow of the electric current from the capacitor to the ignition coil, wherein said switching device is connected on one end to said capacitor and on an opposite end to a high-tension side of said primary coil, and said reverse ON circuit is connected in parallel with said switching device.
a voltage step-up circuit for stepping up a DC voltage;
a capacitor in which an output voltage of said step-up circuit is accumulated;
an ignition coil having a primary coil through which a primary current from said capacitor flows and a secondary coil in which a secondary voltage is induced by said primary current;
an ignition plug connected to said ignition coil for generating a spark discharge upon application thereto of said secondary voltage;
a switching device for permitting the flow of the primary current from said capacitor to said ignition coil at a predetermined time and blocking the flow of the primary current from the ignition coil to the capacitor; and a reverse ON circuit for permitting the flow of the primary current from said ignition coil to said capacitor and blocking the flow of the electric current from the capacitor to the ignition coil, wherein said switching device is connected on one end to said capacitor and on an opposite end to a high-tension side of said primary coil, and said reverse ON circuit is connected in parallel with said switching device.
2. An ignition system as claimed in claim 1, wherein:
said switching device and said primary coil of said ignition coil are connected in series to provide a series circuit; and said capacitor is connected in parallel with said series circuit.
said switching device and said primary coil of said ignition coil are connected in series to provide a series circuit; and said capacitor is connected in parallel with said series circuit.
3. An ignition system as claimed in claim 2, wherein:
said switching device includes a thyristor having an anode connected to said capacitor, a cathode connected to said primary coil of said ignition coil, and a gate to which a timing signal is applied at said predetermined time; and said reverse ON circuit includes a diode having an anode connected to said cathode of said thyristor and a cathode connected to said anode of said thyristor.
said switching device includes a thyristor having an anode connected to said capacitor, a cathode connected to said primary coil of said ignition coil, and a gate to which a timing signal is applied at said predetermined time; and said reverse ON circuit includes a diode having an anode connected to said cathode of said thyristor and a cathode connected to said anode of said thyristor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08-9330 | 1996-01-23 | ||
| JP00933096A JP3555635B2 (en) | 1996-01-23 | 1996-01-23 | Ignition device for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2195793A1 CA2195793A1 (en) | 1997-07-24 |
| CA2195793C true CA2195793C (en) | 2000-10-31 |
Family
ID=11717469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2195793 Expired - Fee Related CA2195793C (en) | 1996-01-23 | 1997-01-22 | Ignition system for internal combustion engines |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3555635B2 (en) |
| CA (1) | CA2195793C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5610457B1 (en) * | 2012-11-30 | 2014-10-22 | 日立オートモティブシステムズ阪神株式会社 | Ignition device for internal combustion engine |
-
1996
- 1996-01-23 JP JP00933096A patent/JP3555635B2/en not_active Expired - Fee Related
-
1997
- 1997-01-22 CA CA 2195793 patent/CA2195793C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP3555635B2 (en) | 2004-08-18 |
| JPH09195908A (en) | 1997-07-29 |
| CA2195793A1 (en) | 1997-07-24 |
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| EEER | Examination request | ||
| MKLA | Lapsed |