JPWO2019211885A1 - Ignition system for internal combustion engine - Google Patents

Abstract

Provided is an ignition device for an internal combustion engine capable of improving ignitability due to spark discharge generated in a spark plug, optimizing power consumption for ignition, and reducing deterioration of fuel efficiency. The superimposition control means 31 of the ignition device 1 for an internal combustion engine superimposes a current on the secondary side of the secondary current superimposition means 50 by satisfying the superimposition control start condition after the ignition timing for cutting off the primary current of the ignition coil 11A. And keep the secondary current at the set secondary current value. After that, when the superimposition control review timing comes, if the set secondary current value is the first current value and the condition of the primary coil voltage satisfies the secondary current addition condition, the second current value is larger than the first current value. If the setting secondary current value is the second current value and the condition of the primary coil voltage satisfies the secondary current reduction condition, the first current value is set. By performing the superimposition reduction control for changing to the next current value, the spark discharge of the ignition plug 20 is greatly expanded and the ignitability is improved.

Description

The present invention relates to an ignition device for an internal combustion engine mounted on an automatic vehicle, and obtains good discharge characteristics by superimposing discharge energy on the secondary side of an ignition coil.

Direct-injection engines and high-EGR engines are used as vehicle-mounted internal combustion engines to improve fuel efficiency, but these engines do not have very good ignitability, so a high-energy type ignition device is required. Become. Therefore, a phase discharge type ignition device has been proposed in which the output of another ignition coil is additively superimposed on the secondary side output of the ignition coil generated by the classical current cutoff principle (for example, Patent Document 1). See).

According to the ignition device described in Patent Document 1, a high voltage of several kV generated on the secondary side of the primary ignition coil by interrupting the primary current causes insulation destruction in the discharge gap of the spark plug to ignite. After starting to flow the discharge current from the secondary side of the coil, the primary current of the sub-ignition coil connected in parallel with the main ignition coil is cut off, and the DC voltage of several kV generated on the secondary side is additionally superimposed. By doing so, it is possible to give a large amount of discharge energy to the spark plug over a relatively long time, so that the ignitability of the fuel is improved, and the fuel efficiency is also improved.

Japanese Unexamined Patent Publication No. 2012-140924

However, in a system such as the ignition device described in Patent Document 1, since the discharge current of the ignition plug is a combination of triangular wave currents output from each coil, two ignitions are used to extend the high current period. The high current period cannot be extended unless the ignition phase of the coils is increased and the time for accumulating sufficient energy in the two ignition coils is lengthened.

In addition, by boosting the power supply voltage outside or inside the ignition coil and applying a high voltage directly to the secondary side of the coil, the discharge energy on the secondary side does not increase the energization time of the primary coil. It is also conceivable to increase the voltage and maintain stable combustion. However, in such a method, since a booster circuit for boosting the power supply voltage to several kV is required, it is necessary to increase the withstand voltage of the mounted circuit and to withstand the connection at a high voltage, resulting in a considerable cost increase. .. In addition, the use of the booster circuit also increases the power consumption for ignition, which causes deterioration of fuel efficiency.

In addition, in order to improve the ignitability of direct injection engines and high EGR engines, it is not enough to extend the high current period, and it is also important to form a large flame by the discharge current of the spark plug. is there. In a normal engine, the flow velocity of the tumble flow generated in the cylinder is about 3 to 5 [m / s], whereas an engine that tries to burn with ultra-lean lean combustion (A / F = 29) or EGR = 35%. Then, when the flow velocity of the tumble flow generated in the cylinder increases to about 20 [m / s], the spark discharge generated in the spark plug is swept by the tumble flow and swells, and the discharge path is extended. When the discharge path of the spark discharge generated in the spark plug is extended, a larger flame nucleus is formed, the flame propagation is improved, and the ignitability can be improved. However, even if the discharge path of the spark discharge generated in the spark plug is extended, if a sufficient discharge current does not flow, the discharge path cannot be maintained, and a new discharge path is created that connects the electrodes of the spark plug with a short path. It causes wrist-like (discharge blowout) and cannot form a flame nucleus of sufficient size. Therefore, in order to improve the ignitability in a direct injection engine or a high EGR engine, it is also important to prevent the recirculation of spark discharge generated in the spark plug. Further, the tumble flow generated in the cylinder is not constant, and may not reach a flow velocity sufficient to expand the discharge path of the spark discharge generated in the spark plug. Even in such a case, if the discharge path of the spark discharge can be adjusted so as to extend, the ignitability can be further improved.

Therefore, the present invention improves the ignitability due to the spark discharge generated in the spark plug by the ignition control according to the tumble flow generated in the cylinder, and further optimizes the power consumption for ignition and reduces the deterioration of fuel efficiency. An object of the present invention is to provide an ignition device for an internal combustion engine.

In order to solve the above problem, the ignition device for an internal combustion engine according to claim 1 applies discharge energy to the secondary side of the ignition coil by controlling the energization of the ignition coil by the ignition control means, and supplies the ignition plug to the ignition plug. In an ignition device for an internal combustion engine that causes a spark discharge, a secondary current overlapping means for maintaining a secondary current value instructed in advance by superimposing a current on the secondary current flowing on the secondary side of the ignition coil. The ignition control means includes a primary coil voltage detecting means for detecting the voltage of the primary coil reflecting the voltage generated in the secondary coil after the ignition timing in the ignition cycle, and the ignition control means starts a predetermined superposition control. When the condition is satisfied, a preset secondary current value is instructed to the secondary current stacking means, so that the secondary current of the set secondary current value is passed to the secondary side of the ignition coil by the secondary current stacking means. When the control is performed and the predetermined superimposition control review timing is reached, the change in the primary coil voltage detected by the primary coil voltage detecting means is determined as a state in which it is difficult to maintain the swollen discharge path of the spark discharge generated in the ignition plug. When the secondary current addition condition is satisfied, a current value higher than the currently set secondary current value is set as the new set secondary current value, and the newly set secondary current value is instructed to the secondary current stacking means. By doing so, superimposition increase control for causing a secondary current having a higher current value to flow from the secondary current stacking means to the secondary side of the ignition coil, and / or the primary coil voltage detected by the primary coil voltage detecting means. When the change satisfies the secondary current reduction condition defined as the state in which the discharge path of the spark discharge generated in the ignition plug is difficult to expand, a current value lower than the currently set secondary current value is newly set as the secondary current value. By setting to and instructing the secondary current stacking means to set a new setting secondary current value, superimposition reduction control that causes a secondary current with a lower current value to flow from the secondary current stacking means to the secondary side of the ignition coil. , Is characterized by doing.

The invention according to claim 2 is the ignition device for an internal combustion engine according to claim 1, wherein the ignition control means spark discharges from the start of superimposition control in one ignition cycle to the superimposition control review timing. It is characterized in that the blowout state, which is a change in the primary coil voltage presumed to have caused the blowout, occurs more than a predetermined number of times as a secondary current addition condition.

The invention according to claim 3 is the ignition device for an internal combustion engine according to claim 1, wherein the ignition control means generates a spark discharge from the start of superimposition control in one ignition cycle to the superimposition control review timing. It is characterized in that the short path holding state, which is a change in the primary coil voltage assumed that the short path is held without expanding the discharge path, is used as the secondary current reduction condition.

Further, the invention according to claim 4 is the ignition device for an internal combustion engine according to any one of claims 1 to 3, wherein the secondary current overlapping means has a predetermined first current value and the same. It is possible to maintain the secondary current value at the second current value higher than the first current value, and the ignition control means superimposes and increases control only when the set secondary current value is the first current value. Is performed, and the superimposition reduction control is performed only when the set secondary current value is the second current value.

In order to solve the above problem, the invention according to claim 5 applies discharge energy to the secondary side of the ignition coil by controlling the energization of the ignition coil by the ignition control means to cause a spark discharge in the ignition plug. In the ignition device for an internal combustion engine, the ignition coil includes a main primary coil in which the amount of forward magnetic flux is increased by energization of the main primary current and the amount of forward magnetic flux is decreased by shutting off the main primary current. The secondary primary coil that generates magnetic flux in the direction opposite to the forward cutoff direction by energizing the secondary primary current at an arbitrary timing after the main primary coil is cut off, and one end side is connected to the ignition plug, and the main primary coil is connected. The voltage of the main primary coil reflects the voltage generated in the secondary coil after the ignition timing in the ignition cycle. The main primary coil voltage detecting means for detecting the above, the secondary current detecting means for detecting the secondary current flowing on the secondary side of the ignition coil, and the interruption generated by switching the energization / interruption of the secondary primary coil. An energy superimposing means for superimposing discharge energy on the secondary side of the ignition coil by applying a superimposing current in the direction to the secondary coil is provided, and the ignition control means satisfies a predetermined superimposition control start condition. By adjusting the superimposition magnetic flux generated by the energy superimposing means based on the secondary current value detected by the secondary current detection means, the secondary current of the preset secondary current value is generated as the secondary current of the ignition coil. When the superimposition control is performed to flow to the side and the predetermined superimposition control review timing is reached, the change in the primary coil voltage detected by the primary coil voltage detecting means maintains the swelling discharge path of the spark discharge generated in the ignition plug. When the secondary current addition condition determined as a difficult state is satisfied, a current value higher than the currently set secondary current value is set as a new set secondary current value, and the superimposed magnetic flux generated by the energy superimposing means is adjusted. By doing so, the superimposition increase control that causes a secondary current having a higher current value to flow to the secondary side of the ignition coil, and / or the change in the primary coil voltage detected by the primary coil voltage detecting means is applied to the ignition plug. When the secondary current reduction condition specified as the state in which the discharge path of the generated spark discharge is difficult to expand is satisfied, a secondary current value lower than the currently set secondary current value is set as the new set secondary current value. By adjusting the superposed current generated by the energy superimposing means, it can be moved to the secondary side of the ignition coil. It is characterized in that superimposition reduction control, in which a secondary current having a low current value is passed, is performed.

The invention according to claim 6 is the ignition device for an internal combustion engine according to claim 5, wherein the ignition control means spark discharges from the start of superimposition control in one ignition cycle to the superimposition control review timing. It is characterized in that the blowout state, which is a change in the primary coil voltage presumed to have caused the blowout, occurs more than a predetermined number of times as a secondary current addition condition.

Further, the invention according to claim 7 is the ignition device for an internal combustion engine according to claim 5, wherein the ignition control means generates a spark discharge from the start of superimposition control in one ignition cycle to the superimposition control review timing. It is characterized in that the short path holding state, which is a change in the primary coil voltage assumed that the short path is held without expanding the discharge path, is used as the secondary current reduction condition.

The invention according to claim 8 is the ignition device for an internal combustion engine according to any one of claims 5 to 7, wherein the energy superimposing means has a duty ratio of a power supply pulse supplied to a secondary primary coil. The superimposed magnetic flux generated in the secondary primary coil can be adjusted by changing the above, and the ignition control means increases or decreases the secondary current by PWM control instructing the energy superimposing means to turn on / off the energization. It is characterized by having made it.

The invention according to claim 9 is the ignition device for an internal combustion engine according to claim 8, wherein the ignition control means has a predetermined first current value and a predetermined second current value higher than the first current value. The current value can be set as the set secondary current value, and the superimposition increase control is performed only when the set secondary current value is the first current value, and when the set secondary current value is the second current value. It is characterized in that superimposition reduction control is performed only on the current.

According to the ignition device for an internal combustion engine according to the present invention, after the ignition timing, superimposition control is performed in which a secondary current of a set secondary current value is passed to the secondary side of the ignition coil by satisfying the superposition control start condition, and then When the superimposition control review timing comes, the ignition control means determines whether the secondary current addition condition or the secondary current reduction condition is satisfied, and it is difficult to maintain the bulging discharge path of the spark discharge generated in the ignition plug. When the current addition condition is satisfied, a superposition increase control that sets a current value higher than the currently set secondary current value to the newly set secondary current value is performed to restore even a strong tumble flow in the cylinder. If the discharge path of the spark discharge is expanded without causing it, and if the secondary current reduction condition, which is a state in which it is difficult to expand the discharge path of the spark discharge generated in the ignition plug, is satisfied, the currently set secondary current value By performing superposition reduction control that sets a lower current value to a new setting secondary current value, the discharge path of spark discharge can be expanded even with a weak tumble flow in the cylinder. As a result, the spark discharge generated between the discharge electrodes of the spark plug can be greatly inflated to form a large flame nucleus in the cylinder, and the ignitability can be improved. Moreover, since the superimposition control by the ignition control means is performed so as to realize the secondary current value according to the strength of the tumble flow generated in the cylinder, the power consumption for the superimposition control can be optimized and the superimposition can be performed. Deterioration of fuel consumption due to control can also be reduced.

It is a schematic block diagram which shows 1st Embodiment of the ignition device for an internal combustion engine which concerns on this invention. It is a schematic block diagram which shows an example of the superimposition control means provided in the internal combustion engine drive control device of the internal combustion engine ignition device which concerns on 1st Embodiment. It is a waveform diagram which shows typically the waveform of the main part of the superimposition control performed by the superimposition control means in 1st Embodiment, and (a) is superimposition increase which changes from a 1st current value to a 2nd current value at a superimposition control review timing. The waveform diagram in the case of performing the control, (b) is the waveform diagram in the case of maintaining the second current value without performing the superposition reduction control at the superimposition control review timing. It is a waveform diagram which shows typically the waveform of the main part of the superimposition control performed by the superimposition control means in 1st Embodiment, and (a) is superimposition reduction which changes from a 2nd current value to a 1st current value at a superimposition control review timing. The waveform diagram in the case of performing control, (b) is the waveform diagram in the case of maintaining the first current value without performing the superposition increase control at the superimposition control review timing. It is a schematic block diagram which shows the 2nd Embodiment of the ignition device for an internal combustion engine which concerns on this invention. It is a schematic block diagram which shows an example of the superimposition control means provided in the internal combustion engine drive control device of the internal combustion engine ignition device which concerns on 2nd Embodiment. It is a waveform diagram which shows typically the waveform of the main part of superimposition control performed by superimposition control means in 2nd Embodiment, and (a) is superimposition increase which changes from a 1st current value to a 2nd current value at a superimposition control review timing. The waveform diagram in the case of performing the control, (b) is the waveform diagram in the case of maintaining the second current value without performing the superposition reduction control at the superimposition control review timing. It is a waveform diagram which shows typically the waveform of the main part of superimposition control performed by superimposition control means in 2nd Embodiment, and (a) is superimposition reduction which changes from a 2nd current value to a 1st current value at a superimposition control review timing. The waveform diagram in the case of performing control, (b) is the waveform diagram in the case of maintaining the first current value without performing the superposition increase control at the superimposition control review timing.

Next, an embodiment of the ignition device for an internal combustion engine according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an ignition device 1 for an internal combustion engine according to the first embodiment of the present invention, which includes an ignition coil unit 10A for generating spark discharge in one spark plug 20 provided for each cylinder of the internal combustion engine. Spark discharge occurs in the internal combustion engine drive control device 30A as an ignition control means for outputting an ignition signal Si or the like indicating the operation timing of the ignition coil unit 10A at an appropriate timing, a DC power supply 40 such as a vehicle battery, and a spark plug 20. As a result, it is composed of a secondary current stacking means 50 or the like in which a current is further superposed on the secondary current flowing on the secondary side of the ignition coil. The secondary current stacking means 50 functions as an energy superimposing means capable of increasing the discharge energy by superimposing energy on the secondary side of the ignition coil 11A included in the ignition coil unit 10A.

In the internal combustion engine ignition device 1 shown in the present embodiment, the function as an ignition control means is included in the internal combustion engine drive control device 30A that comprehensively controls the internal combustion engine of an automobile. It is not limited. For example, it receives an ignition signal generated by an ignition signal generation function of a normal internal combustion engine drive control device 30A such as an ECU, generates an appropriate control signal, and generates an appropriate control signal to the ignition coil unit 10A and the secondary current stacking means 50. An ignition control device that outputs a control signal to the internal combustion engine may be provided separately.

The ignition coil unit 10A has an integrated structure in which, for example, an ignition coil 11A, an ignition switch 12A, a bypass line 13 provided in parallel with the ignition switch 12A, a rectifying means 14 provided on the bypass line 13, and the like are housed in a case 15 having a required shape. It is a unit. A high-voltage terminal 151 and a connector 152 are provided at appropriate positions in the case 15, and the spark plug 20 is connected via the high-voltage terminal 151 and also connected to the internal combustion engine drive control device 30A and the DC power supply 40 via the connector 152. To do.

The ignition coil 11A efficiently causes the magnetic flux generated in the primary coil 111 to act on the secondary coil 112. For example, the primary coil 111 is arranged so as to surround the center core 113, and the secondary coil 112 is further outside the primary coil 111. It is an arranged structure. The first end 111-1, which is one end of the primary coil 111, is connected to the DC power supply 40 via the connector 152, and a power supply voltage VB + (for example, 12V) is applied. The second end 111-2, which is the other end of the primary coil 111, is connected to the collector of the ignition switch 12A, and the emitter of the ignition switch 12A is connected to the grounding point GND via the connector 152.

Then, when the ignition signal Si output from the internal combustion engine drive control device 30A is input to the gate of the ignition switch 12A at an appropriate timing of the discharge cycle (for example, when the signal level of the ignition signal Si changes from L to H). , The ignition switch 12A is turned on, the second end 111-2 of the primary coil 111 is connected to the grounding point GND, and the primary coil 111 has a primary current I1 from the first end 111-1 to the second end 111-2. Starts to flow, and the flow rate of the primary current I1 increases exponentially. The amount of magnetic flux corresponding to the flow rate of the primary current I1 is stored as the energy of the magnetic field. On the secondary side of the ignition coil 11A, electric energy is accumulated by a minute capacitor component such as the secondary coil 112 and the connection wiring.

After the energy is accumulated as described above, when the energization of the primary coil 111 is cut off at a predetermined ignition timing, a high-voltage electromotive force is generated in the secondary coil 112 and spark discharge is performed between the discharge gaps of the spark plug 20. Occurs and ignites the air-fuel mixture in the cylinder combustion chamber. At this time, since a voltage in the opposite direction is generated in the primary coil 111 to allow a current to flow in the direction opposite to that of the normal primary current I1, and this counter electromotive force is applied between the collector and the emitter of the ignition switch 12A. Therefore, there is a risk that the ignition switch 12A may break down or the ignition switch 12A may be deteriorated earlier. Therefore, a bypass line 13 is provided in parallel with the ignition switch 12A, and a rectifying means 14 (for example, a cathode is provided on the collector side of the ignition switch 12A) in the forward direction from the grounding point side of the bypass line 13 toward the ignition coil 11A side. , A diode in which an anode is connected to each of the emitters of the ignition switch 12A) is provided.

Since the secondary current I2 in which spark discharge occurs between the discharge electrodes of the spark plug 20 and flows to the secondary side is useful as information for knowing the combustion state in the cylinder, it is for detecting the secondary current I2. A secondary current detecting means may be provided. The secondary current detecting means includes, for example, a current detecting resistor 61 having an appropriate resistance value inserted in the secondary current path between the secondary current overlapping means 50 and the grounding point GND, and the current detecting resistor 61. It can be configured with a secondary current detection line 62 that acquires the voltage change due to the above as secondary current detection information (secondary current detection signal). Then, the secondary current detection signal obtained from the secondary current detection line 62 is supplied to the internal combustion engine drive control device 30A, and the internal combustion engine drive control device 30A flows to the secondary coil 112 based on the secondary current detection signal. You can know the current value.

Further, the voltage generated in the secondary coil 112 that applies a high voltage to the ignition plug 20 (hereinafter referred to as the secondary coil voltage) is also useful as information for knowing the combustion state. Therefore, for example, the high voltage terminal 151 It is sufficient to acquire the secondary coil voltage information at the detection point Psp set between the secondary coil 112 and the secondary coil 112, but since the secondary coil voltage is a high voltage ranging from several kV to several tens of kV, It is necessary to consider various problems such as the occurrence of leakage due to the provision of the voltage dividing resistor, and it is not realistic to monitor the secondary coil voltage at the detection point Psp.

However, when the spark plug 20 is discharged, a voltage corresponding to the turns ratio between the primary coil 111 and the secondary coil 112 is also generated in the primary coil 111, and the voltage generated in the primary coil 111 (hereinafter referred to as the primary coil). If it is (called voltage), it is a relatively low voltage value, so the difficulty level for monitoring is low. However, the primary coil voltage and the secondary coil voltage have different scales of voltage values and have opposite polarities to each other. Based on this difference, the primary coil voltage can be treated as the correlation information of the secondary coil voltage.

Therefore, in the ignition coil unit 10A of the ignition device 1 for an internal combustion engine according to the present embodiment, the second end 111-2 of the primary coil 111 and the bypass line are used as the primary coil voltage detecting means for detecting the voltage on the low voltage side of the primary coil. The primary coil voltage detection line 16 is pulled out from between the branch points of 13 and the primary coil voltage signal is input to the internal combustion engine drive control device 30A via the connector 152.

In the internal combustion engine drive control device 30A, since it is possible to know the change in the voltage applied to the spark plug 20 by estimating the secondary coil voltage based on the primary coil voltage signal, the internal combustion engine drive control device 30A can be used. By controlling the superposition of the secondary current by the secondary current stacking means 50, the ignitability can be improved. The superimposition control using the secondary current superimposition means 50 is executed by, for example, the function of the superimposition control means 31 provided in the internal combustion engine drive control device 30A. Further, as the current source of the secondary current stacking means 50, a DC power source 40 such as a vehicle battery can be used.

An example of the superimposition control means 31 is shown in FIG. The superimposition control means 31 includes a superimposition control timing determination means 301 that determines the start and end timings of the superimposition control, and a superimposition control start condition that the superimposition control timing determination means 301 uses as information for determining the superimposition control start timing. Generates and outputs the superimposition control start condition storage means 302 that stores (detailed later) and the secondary current superimposition control signal Sp for operating and controlling the secondary current superimposition means 50 when the superimposition control is started. The secondary current overlap control signal generation means 303, the setting secondary current value storage means 304 for storing the set secondary current value set as the target value of the secondary current flowing to the secondary side of the ignition coil, and the secondary current value storage means 304. Changeable secondary current value storage means 305 that stores the types of secondary current values that the current stacking means 50 can hold by adjusting the superposed current (for example, two types, the first current value and the second current value). The superimposition control review timing storage means 306 for storing the superimposition control review timing for reviewing whether or not the superimposition control is optimized after the superimposition control start condition is satisfied and the superimposition control is started is provided.

The superimposition control timing determination means 301 is supplied with the ignition signal Si, the primary coil voltage signal, and the superimposition control start condition storage means 302, and after the ignition timing IG from which the ignition signal Si is turned from ON to OFF. In addition, it is determined that the superimposition control start timing α1 that satisfies the superimposition control start condition is satisfied. For example, as shown in the waveform diagram of FIG. 3A, the capacitance discharge energy (electrical energy stored on the secondary side) is consumed by the ignition timing IG due to the primary current cutoff, and the primary voltage rises sharply (FIG. 3). In the primary coil voltage waveform of (a), it becomes large at the negative electrode), decreases in a short time (returns to the positive electrode side in the primary coil voltage waveform of FIG. 3 (a)), and reaches a predetermined index value voltage. The reached timing is determined as the superimposition control start timing α1. When paying attention to the change in the primary coil voltage for superimposition control, it is not necessary to consider the polarity with respect to the reference potential. Therefore, the absolute value of the waveform voltage is used as the voltage value to determine the increase or decrease of the value. The superimposition control start condition may also be set as a positive value.

Further, the superimposition control start condition may be set arbitrarily, and for example, it can be considered that a predetermined period (for example, several tens of μs) that can be regarded as a capacitance discharge has elapsed and the state has shifted to an induced discharge. When this is set as the superimposition control start condition, the superimposition control timing determination means 301 stores the superimposition control start condition storage means 302 by storing the passage of a predetermined period from the discharge timing IG in the superimposition control start condition storage means 302. It is possible to determine the superimposition control start timing using the superimposition control start condition obtained from the above and instruct the secondary current superimposition control signal generation means 303 to start generating the secondary current superimposition control signal. The superimposition control start condition to be stored in the superimposition control start condition storage means 302 can be arbitrarily changed by inputting a superimposition control start condition setting signal from the outside, so that the superimposition control start condition can be flexibly changed according to the characteristics of the internal combustion engine. Since the superimposition control start condition can be set, convenience can be improved.

When the superimposition control timing determination means 301 determines that the superimposition control start timing α1 and issues a secondary current superimposition start instruction to the secondary current superimposition control signal generation means 303, the secondary current superimposition control signal generation means 303 performs secondary current superimposition. A control signal Sp is generated and output to the secondary current superimposing means 50, and the secondary current is superposed by the secondary current superimposing means 50 (in the secondary current waveform of FIG. 3A, the shaded area is shown. reference).

Here, the secondary current superimposition signal Sp takes, for example, two signal levels in order to instruct the secondary current superimposition means 50 of the set secondary current value stored in the set secondary current value storage means 304. .. When the set secondary current value stored in the set secondary current value storage means 304 is the first current value, the potential of the secondary current overlap control signal Sp generated by the secondary current overlap signal generation means 303 is set to Lev1. Then, the secondary current stacking means 50 that receives this shows that the target secondary current value is the first current value from the potential level of the secondary current stacking control signal Sp, and the secondary side of the ignition coil is set. The secondary current stacking operation is performed by the secondary current stacking means 50 so that the flowing secondary current holds the first current value.

Similarly, when the set secondary current value stored in the set secondary current value storage means 304 is the second current value, the secondary current overlap control signal Sp generated by the secondary current overlap signal generation means 303 By setting the potential to Lev2, the secondary current stacking means 50 that receives this shows that the target secondary current value is the second current value from the potential level of the secondary current stacking control signal Sp, and the ignition coil 2 The secondary current stacking operation is performed by the secondary current stacking means 50 so that the secondary current flowing on the secondary side holds the secondary current value.

When there are three or more types of current values stored in the changeable secondary current value storage means 305, the secondary current overlap control signal Sp is generated at the potential level corresponding to each current value. Alternatively, the signal line from the internal combustion engine drive control device 30A to the secondary current stacking means 50 may be physically separated, and the target current value may be set according to the signal line that outputs the secondary current stacking control signal Sp. May be instructed to the secondary current stacking means 50.

After the superimposition control is started as described above, the superimposition control timing determination means 301 determines the success or failure of the superimposition control review timing α2 stored in the superimposition control review timing storage means 306. The superimposition control review timing is, for example, the timing at which the ignition status monitoring period tx of a predetermined time width elapses from the superimposition control start timing α1, and the discharge path of the spark discharge generated between the discharge electrodes of the ignition coil 20 is the tumble flow in the cylinder. It is used as a timing to determine whether or not it is presumed to be inflated by. Since the ignition status monitoring period tx having an appropriate time width changes depending on the characteristics of the internal combustion engine and the operating environment, for example, the stored contents of the superimposition control review timing storage means 306 can be arbitrarily set by an external superimposition control review timing setting signal. If you can change it to, it will be very convenient.

The superimposition control timing determination means 306 monitors the change in the primary coil voltage detected by the primary coil voltage detection means and ignites until the superimposition control review timing α2 is established (until the ignition status monitoring period tx elapses). The secondary current addition condition defined as a state in which it is difficult to maintain the expanded discharge path of the spark discharge generated in the plug 20, or the secondary current reduction defined as a state in which the discharge path of the spark discharge generated in the spark plug 20 is difficult to expand. Judge the success or failure of the condition. Then, when the secondary current addition condition is satisfied, the superimposition control timing determination means 301 instructs the secondary current superimposition control signal generation means 303 to perform superimposition increase control. When the secondary current reduction condition is satisfied, the superimposition control timing determination means 301 instructs the secondary current superimposition control signal generation means 303 to perform superimposition reduction control. If neither the secondary current addition condition nor the secondary current reduction condition is satisfied, the superimposition control timing determination means 301 does not give an instruction to the secondary current superposition control signal generation means 303.

First, a case where the superimposition control timing determination means 306 determines that the change in the primary coil voltage satisfies the secondary current addition condition will be described.

As an example of the secondary current addition condition, the blowout waveform, which is considered to be in a state where the absolute value of the primary coil voltage rises above the index voltage value but falls below the index voltage value again, is monitored for ignition status. It occurs more than a predetermined number of times (for example, once) during the period tx. This blowout waveform shows the flow velocity of the tumble flow due to the voltage rise generated to maintain the discharge current in the process of expanding the spark discharge generated between the discharge electrodes of the ignition plug 20 by the tumble flow. In contrast, the bulging discharge path could not be maintained, and the discharge path changed to a short path flowing between the discharge electrodes, so that the voltage between the electrodes dropped. That is, the fact that the blowout waveform was detected during the ignition status monitoring period tx means that the flow velocity of the tumble flow acting between the electrodes of the spark plug 20 in the cylinder is stronger than the discharge current (secondary current). It is considered too much. Therefore, increasing the secondary current so that the tumble flow generated at this time does not cause blowout is effective in realizing stable combustion. Therefore, the blowout waveform is generated a predetermined number of times or more during the ignition status monitoring period tx. That is the condition for adding the secondary current.

The above-mentioned secondary current addition condition is merely an example, and may be appropriately set according to the characteristics of the internal combustion engine and the like. For example, even if a blowout waveform is detected at the initial stage of the ignition status monitoring period tx, if the voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2, between the electrodes of the spark plug 20. Since it can be estimated that the generated spark discharge is in a state of being greatly inflated without being blown out, it is not necessary to increase the secondary current even in such a case, so this should be excluded from the secondary current addition condition. You can do it.

During the ignition status monitoring period tx in which the superimposition control timing determination means 301 monitors the change in the primary coil voltage to determine the success or failure of the secondary current addition condition, the superimposition control determination timing determination means 301 instructs the superimposition control timing determination means 301 to start the superimposition control. The secondary current stacking control signal generation means 303 receives the secondary current stacking control signal for operating the secondary current stacking means 50 with the set secondary current value stored in the set secondary current value storage means 304. Sp is generated and output to the secondary current stacking means 50. For example, if the set secondary current value stored in the set secondary current value storage means 304 is the first current value, the secondary current superposition control signal generation means 303 sets the potential level of the signal to Lev1. By outputting the current superposition control signal Sp to the secondary current superposition means 50, superimposition control for holding the secondary current at the first current value is performed.

As described above, the superimposition control review timing α2 is set in the state where the secondary current is held at the first current value by the secondary current superposition means 50, and the superimposition control timing determination means 301 determines that the secondary current addition condition is satisfied. Then, the secondary current superposition control signal generation means 303 is instructed to perform superimposition increase control. As a result, the secondary current superposition control signal generation means 303 is stored in the set secondary current value storage means 304 among the changeable secondary current values read from the changeable secondary current value storage means 305. A secondary current value (second current value) higher than the secondary current value (first current value) is set as a new set secondary current value. The secondary current value storage means 304 is overwritten and the potential level of the signal is set to Lev2. By outputting the secondary current superposition control signal Sp to the secondary current superposition means 50, superimposition control for holding the secondary current at a second current value higher than the first current value is performed.

That is, by performing the superimposition increase control, the superimposition control is performed in which the secondary current value is changed to a higher second current value than the first current value used as an index during the ignition status monitoring period tx, and the secondary current is held at the second current value. When this happens, a large discharge current will flow so that it will not easily be blown out even with a strong tumble flow generated in the cylinder. Therefore, the spark discharge generated between the electrodes of the spark plug 20 swells greatly without being blown out, and a large flame nucleus can be formed in the cylinder, so that suitable combustion can be realized.

The first current value used as the set secondary current value in the superimposition control is not blown out by the average tumble current generated during the standard operation of the internal combustion engine to be controlled, and the discharge path is sufficiently expanded. The secondary current value at that time may be set as an index. Further, the second current value can be determined by using the secondary current value when the discharge path is sufficiently expanded without being blown out by the strong tumble flow generated when the internal combustion engine to be controlled is overloaded. good.

On the other hand, in the ignition cycle performed after the set secondary current value of the set secondary current value storage means 304 is changed from the first current value to the second current value as described above, the waveform diagram of FIG. 3 (b) is shown. As shown, when the primary coil voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2 without the blowout waveform appearing during the ignition status monitoring period tx, the electrode of the ignition plug 20 Since it is considered that the spark discharge generated between them swells greatly without being blown out, the secondary current addition condition is not satisfied, and the superimposition control timing determination means 301 to the secondary current superimposition control signal generation means 303. Since the superimposition increase control is not instructed, the second current value stored in the set secondary current value storage means 304 is maintained as it is, and the secondary current is set to the second current value by the secondary current stacking means 50. The superimposition control held in is continued.

The end timing of the superimposition control performed by the superimposition control means 31 is arbitrary. For example, the timing at which the primary coil voltage drops to a predetermined superimposition stop reference voltage value is set as the superimposition control end timing β, and when this superimposition control end timing β is reached, the superimposition control timing determination means 301 generates a secondary current overlap control signal. By stopping the superimposition control instruction to the means 303 (or outputting the superimposition control end instruction), the secondary current superimposition control signal generation means 303 outputs the secondary current superimposition control signal Sp to the secondary current superimposition means 50. Without it, the secondary current superimposition function by the secondary current stacking means 50 can be stopped. Further, when the elapsed time measured from the ignition timing IG reaches the high current holding time defined as the high current period necessary and sufficient for maintaining stable combustion, the superimposition control end timing β is set and the superimposition control is terminated. You can do it.

Next, a case where the superimposition control timing determination means 306 determines that the change in the primary coil voltage satisfies the secondary current reduction condition will be described.

As an example of the secondary current reduction condition, as shown in FIG. 4A, the short path holding waveform is such that no voltage rise exceeding the index voltage value is observed even once during the ignition status monitoring period tx. .. This short-path holding waveform shows a state in which the spark discharge generated between the discharge electrodes of the spark plug 20 is not extended by the tumble flow, and the voltage rise does not occur because the short-path discharge current is held. .. That is, the fact that the ignition status monitoring period tx has a short path holding waveform means that the discharge current (secondary current) is the flow velocity of the tumble flow acting between the electrodes of the spark plug 20 in the cylinder. It is considered too strong. Therefore, reducing the secondary current so that the spark discharge path is well extended by the tumble flow generated at this time is effective for realizing stable combustion. Therefore, the short path holding waveform during the ignition status monitoring period tx. Is maintained as a secondary current reduction condition.

During the ignition status monitoring period tx in which the superimposition control timing determination means 301 monitors changes in the primary coil voltage to determine the success or failure of the secondary current reduction condition, the superimposition control determination timing determination means 301 instructs the superimposition control timing determination means 301 to start superimposition control. The secondary current stacking control signal generation means 303 receives the secondary current stacking control signal for operating the secondary current stacking means 50 with the set secondary current value stored in the set secondary current value storage means 304. Sp is generated and output to the secondary current stacking means 50. For example, if the set secondary current value stored in the set secondary current value storage means 304 is the second current value, the secondary current overlap control signal generation means 303 sets the potential level of the signal to Lev2. By outputting the current superposition control signal Sp to the secondary current superposition means 50, superimposition control for holding the secondary current at the second current value is performed.

As described above, the superimposition control review timing α2 is set in the state where the secondary current is held at the second current value by the secondary current superposition means 50, and the superimposition control timing determination means 301 determines that the secondary current reduction condition is satisfied. Then, the secondary current overlap control signal generation means 303 is instructed to perform superimposition reduction control. As a result, the secondary current superposition control signal generation means 303 is stored in the set secondary current value storage means 304 among the changeable secondary current values read from the changeable secondary current value storage means 305. A secondary current value (first current value) lower than the secondary current value (second current value) is set as a new set secondary current value. The secondary current value storage means 304 is overwritten, and the potential level of the signal is set to Lev1. By outputting the secondary current superposition control signal Sp to the secondary current superposition means 50, superimposition control for holding the secondary current at a first current value lower than the second current value is performed.

That is, by performing the superimposition reduction control, the superimposition control is performed in which the primary current value is changed to a lower current value than the second current value used as an index during the ignition status monitoring period tx, and the secondary current is held at the first current value. When this happens, the discharge path swells greatly even with a weak tumble flow generated in the cylinder, and a discharge current that does not blow out will flow. Therefore, the spark discharge generated between the electrodes of the spark plug 20 swells greatly without being blown out, and a large flame nucleus can be formed in the cylinder, so that suitable combustion can be realized.

On the other hand, in the ignition cycle performed after the set secondary current value of the set secondary current value storage means 304 is changed from the second current value to the second current value as described above, the waveform diagram of FIG. 4 (b) is shown. As shown, when the primary coil voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2 without the blowout waveform or short path holding waveform appearing during the ignition status monitoring period tx. Since it is considered that the spark discharge generated between the electrodes of the ignition plug 20 is greatly expanded without being blown out, neither the secondary current reduction condition nor the secondary current increase condition is satisfied, and the superimposition control timing determination means 301 Since the superimposition reduction control and superimposition increase control are not instructed to the secondary current overlap control signal generation means 303, the first current value stored in the set secondary current value storage means 304 is maintained as it is. Superimposition control for holding the secondary current at the first current value is continuously performed by the secondary current overlapping means 50. Then, when the superimposition control end timing β is reached, the superimposition control for holding the secondary current at the first current value ends.

As described above, in the superimposition control means 31 in the ignition device 1 for an internal combustion engine according to the first embodiment, after the superimposition control is started, at the superimposition control review timing α2, the secondary current increase condition and the secondary current decrease condition are satisfied. Based on the success or failure, it is determined whether or not superimposition increase control or superimposition reduction control is necessary, and by executing superimposition increase control or superimposition reduction control as necessary, spark discharge generated between the electrodes of the spark plug 20 can be generated. It swells greatly without being blown out, allowing the formation of large flame nuclei in the cylinder and achieving suitable combustion.

However, in the ignition device 1 for the internal combustion engine of the present embodiment, since the changeable secondary current value storage means 305 stores only two types, the first current value and the second current value, the set secondary current value is stored. When the set secondary current value stored in the means 304 is the second current value, the superimposition increase control cannot be performed even if the secondary current increase condition is satisfied. Similarly, the setting 2 When the set secondary current value stored in the secondary current value storage means 304 is the first current value, the superimposition reduction control cannot be performed even if the secondary current reduction condition is satisfied. That is, the internal combustion engine ignition device 1 according to the present embodiment can only control either the superimposition increase control or the superimposition decrease control according to the set secondary current value.

However, there are three or more types of changeable secondary current value storage means 305 (for example, a first current value, a second current value, and a third current value, and the first current value <second current value <third current. If the value) is stored, the superimposition increase control and the superimposition reduction control can be performed more finely, and the set secondary current value stored in the set secondary current value storage means 304 is the upper limit current value (the first). If the intermediate current value (second current value) is neither the third current value) nor the lower limit current value (first current value), the superimposition increase control can be performed when the secondary current increase condition is satisfied, and the secondary current reduction can be performed. When the condition is satisfied, the superimposition reduction control can be performed. That is, if the changeable secondary current value storage means 305 stores three or more types and the secondary current stacking means 50 can hold the secondary current at three or more types of current values, depending on the conditions for establishment. In some cases, both superimposition increase control and superimposition reduction control can be performed.

Further, as in the ignition device 1 for an internal combustion engine of the first embodiment described above, the success or failure of the secondary current increase condition and the secondary current decrease condition is determined within the ignition cycle, and the superposition increase is performed in order to correct within the same cycle. If control or superimposition reduction control is performed, it is possible to eliminate the variation in each ignition cycle and realize stable combustion, but it is not always necessary to judge the success or failure of the secondary current increase condition and the secondary current reduction condition within the same cycle. There is no. For example, if the ignition cycle continues for a predetermined number of times, although the combustion in the cylinder is not hindered, but the tendency of blowout is observed, the superposition increase control is performed assuming that the secondary current increase condition is satisfied, and the cylinder is operated. When the ignition cycle in which the short path holding tendency is observed continues for a predetermined number of times, although it does not hinder the combustion inside, the superimposition reduction control may be performed assuming that the secondary current reduction condition is satisfied.

In the ignition device 1 for an internal combustion engine according to the first embodiment described above, the secondary current overlapping means 50 capable of directly controlling the secondary current flowing on the secondary side of the ignition coil 11A is used as the energy superimposing means. The superimposing means is not limited to this. For example, as in the ignition device 2 for an internal combustion engine according to the second embodiment shown in FIG. 5, an ignition plug is obtained by superimposing inductive discharge energy from the primary side to the secondary side of the ignition coil after the ignition timing IG. It is also possible to improve the ignitability due to the spark discharge generated in No. 20.

The ignition device 2 for an internal combustion engine shown in FIG. 5 is different from the ignition device 1 for an internal combustion engine according to the first embodiment, and has an ignition coil unit 10B provided with an ignition coil 11B and a drive control function corresponding to the ignition coil unit 10B. It has an internal combustion engine drive control device 30B, a sub-primary coil energization permission switch 71 for performing ignition control of the ignition coil 11B, and a sub-primary coil energization switch 72. Further, the internal combustion engine drive control device 30B includes a superimposition control means 32 that superimposes discharge energy on the secondary side by controlling the ignition coil 11B. The same configuration as that of the ignition device 1 for an internal combustion engine according to the first embodiment described above will be designated by the same reference numerals and description thereof will be omitted.

The ignition coil 11B of the ignition coil unit 10B efficiently acts the magnetic flux generated in the main primary coil 111a (for example, 90 turns) and the secondary primary coil 111b (for example, 60 turns) on the secondary coil 112 (for example, 9000 turns). For example, the main primary coil 111a and the secondary primary coil 111b are arranged so as to surround the center core 113, and the secondary coil 112 is further arranged outside the main primary coil 111a.

First, the first end 111a-1, which is one end of the main primary coil 111a, is connected to the DC power supply 40 via the connector 152, and a power supply voltage VB + (for example, 12V) is applied. The second end 111a-2, which is the other end of the main primary coil 111a, is connected to the collector of the main ignition switch 12B, and the emitter of the main ignition switch 12B is connected to the grounding point GND via the connector 152. To. That is, when the main primary coil ignition signal Sa output from the internal combustion engine drive control device 30B is input to the gate of the main ignition switch 12B (for example, when the signal level of the main primary coil ignition signal Sa changes from L to H). , The main ignition switch 12B is turned on, the second end 111a-2 of the main primary coil 111a is connected to the grounding point GND, and the main primary coil 111a goes from the first end 111a-1 to the second end 111a-2. The main primary current I1a flows, and a forward magnetic flux (energized magnetic flux) is generated.

Then, when the main primary coil ignition signal Sa output from the internal combustion engine drive control device 30B is turned off (for example, when the signal level of the main primary coil ignition signal Sa changes from H to L), the main ignition switch 12B is turned off. As a result, the energization of the main primary coil 111a is cut off. As a result, the discharge energy due to the capacitive component is given to the secondary coil 112, spark discharge occurs between the discharge electrodes of the spark plug 20, and the energizing magnetic flux acting on the secondary coil 112 via the center core 113. Disappears rapidly. This attenuation of the current-carrying magnetic flux is apparently regarded as a magnetic flux in the opposite direction to the current-carrying magnetic flux (hereinafter referred to as a breaking magnetic flux) that reduces the current-carrying magnetic flux. That is, the magnetic flux amount of the energizing magnetic flux is reduced by the breaking magnetic flux generated by the energizing cutoff of the main ignition coil 111a, and the change in the magnetic flux amount causes a high-pressure electromotive force according to the winding ratio of the primary side and the secondary side. Since it is generated in the secondary coil 112, the discharge energy due to the inductive component is given to the secondary side of the ignition coil 11B.

On the other hand, similarly to the main primary coil 111a, the secondary primary coil 111b capable of applying a magnetic field to the secondary coil 112 via the iron core 113 has a connector 152 at the first end 111b-1, which is one end thereof. It is connected to the sub-primary coil energization switch 72 via the connector 152, and the second end 111b-2, which is the other end, is connected to the sub-primary coil energization permission switch 71 via the connector 152. Then, the internal combustion engine drive control device 30B controls the on / off of the sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72, and the first end 111b-1 side of the sub-primary coil 111b is connected to the DC power supply 40. When the two-end 111b-2 side is connected to the grounding point GND, a superimposed current I1b flowing from the first end 111b-1 to the second end 111b-2 flows through the secondary primary coil 111b.

When the superimposed current I1b flows through the secondary primary coil 111b, the magnetic flux generated when the DC power supply 40 energizes the main primary coil 111a is in the opposite direction (the magnetic flux that is virtually generated when the main primary coil 111a is de-energized). Superimposed magnetic flux (in the same direction) is generated. That is, if the superimposed current I1b is passed through the secondary primary coil 111b after the energization cutoff timing of the main primary coil 111a, the superimposition magnetic flux is added to the breaking magnetic flux, so that the attenuation of the energization magnetic flux is accelerated, and the secondary coil The induced discharge energy induced in 112 can be increased in a superimposed manner. Therefore, in the ignition device 2 for an internal combustion engine of the second embodiment using the ignition coil 11B, the sub-primary coil 111b and the sub-primary coil energization permission switch 71 and the sub-primary that control energization / disconnection of the sub-primary coil 111b are performed. The coil energization switch 72 functions as an energy superimposing means capable of increasing the discharge energy by superimposing energy on the secondary side of the ignition coil 11B.

In this way, if the superposed magnetic flux is generated by the secondary primary coil 111b and the induced discharge energy on the secondary side is adjusted, the current value of the secondary current can be controlled. The discharge path of the spark discharge swells greatly without being blown out by the tumble current, forming a large flame nucleus, and suitable combustion can be realized. In order to reverse the directions of the energizing magnetic flux and the superposed magnetic flux (to make the superposed magnetic flux the same direction as the breaking magnetic flux), the winding directions of the main primary coil 111a and the secondary primary coil 111b should be reversed, or the main The feeding direction to the primary coil 111a and the feeding direction to the secondary primary coil 111b may be reversed.

The sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72 used for energization control of the ignition coil 11B described above may be provided separately, or the sub-primary coil provided separately from the ignition coil unit 10B. The unit structure may be such that the energization permission switch 71 and the sub-primary coil energization switch 72 are housed in the same case. Further, if a semiconductor device having high withstand voltage and noise resistance is used as the sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72, it may be provided in the case 15 of the ignition coil unit 10B.

The sub-primary coil energization permission switch 71 can be configured by a power MOS-FET having high-speed switching characteristics, and the source of the sub-primary coil energization permission switch 71 is on the second end 111b-2 side of the sub-primary coil 111b to energize the sub-primary coil. The drain of the permission switch 71 is connected to the grounding point GND side, and the sub-primary coil energization permission signal Sb1 is input to the gate of the sub-primary coil energization permission switch 71 from the superimposition control means 32 of the internal combustion engine drive control device 30B. Therefore, when the sub-primary coil energization permission signal Sb1 is turned on (for example, the signal level is from L to H), the sub-primary coil energization permission switch 71 is turned on, and the second end 111b-2 of the sub-primary coil 111b is the grounding point. It will be connected to GND.

A current detection resistor 81 having an appropriate resistance value is inserted in the secondary primary current path between the drain of the secondary primary coil energization permission switch 71 and the grounding point GND, and the voltage due to the current detection resistor 81 is inserted. The sub-primary voltage detection line 82 for detecting the change and the current detection resistor 81 constitute the sub-primary current detection means. The secondary primary current detection signal obtained from the secondary primary voltage detection line 82 is supplied to the internal combustion engine drive control device 30B, and the superimposition control means 32 transfers the secondary primary current flowing through the secondary primary coil 111b based on the secondary primary current detection signal. You can know.

Further, the sub-primary coil energizing switch 72 can also be configured by a power MOS-FET, the drain of the sub-primary coil energizing switch 72 is on the DC power supply 40 side, and the source of the sub-primary coil energizing switch 72 is the first end 111b of the sub-primary coil 111b. The sub-primary coil energization signal Sb2 is input from the superimposition control means 32 to the gate of the sub-primary coil energization switch 72 connected to the -1 side. Therefore, when the sub-primary coil energization signal Sb2 is turned on (for example, the signal level is from L to H), the sub-primary coil energizing switch 72 is turned on, and the DC power supply 40 is connected to the first end 111b-1 of the sub-primary coil 111b. The power supply voltage VB + will be applied. A boost power supply circuit 73 (indicated by a two-dot chain line in FIG. 5) may be provided so that the power supply voltage VB + from the DC power supply 40 can be boosted and supplied to the secondary primary coil 111b. By doing so, the voltage applied to the secondary primary coil 111b can be increased to increase the superimposed current I1b flowing through the secondary primary coil 111b, so that a larger energy can be superimposed from the secondary primary coil 111b to the secondary coil 112. It will be possible.

When the superimposition control means 32 controls the energization of the secondary primary coil 111b, the voltage generated in the main primary coil 111a (hereinafter referred to as the main primary coil voltage) is used as the correlation information of the secondary coil voltage. Therefore, in the ignition coil unit 10B of the ignition device 2 for an internal combustion engine according to the present embodiment, the second end 111a-2 of the main primary coil 111a is used as the main primary coil voltage detecting means for detecting the voltage on the low voltage side of the main primary coil. The main primary coil voltage detection line 17 is pulled out from between the branch point of the bypass line 13 and the branch point of the bypass line 13, and the main primary coil voltage signal is input to the superimposition control means 32 of the internal combustion engine drive control device 30B via the connector 152.

An example of the superimposition control means 32 is shown in FIG. The superimposition control means 32 uses a superimposition control timing determination means 301 for determining the control timing of the start / update and end of superimposition and information for determining the superimposition control start control timing by the superimposition control timing determination means 301. The superimposition control start condition storage means 302 that stores the superimposition control start condition and the superimposition control timing determination means 301 that store the superimposition control review timing that is used as information for determining the superimposition control review timing. Generates and outputs the timing storage means 306, the sub-primary coil energization permission signal Sb1 and the sub-primary coil energization signal Sb2 for operating the sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72 when the superimposition control is started. The secondary primary coil control means 307, the set secondary current value storage means 304 for storing the set secondary current value set as the target value of the secondary current flowing to the secondary side of the ignition coil, and the secondary primary coil 111b. A changeable secondary current value storage means 305 for storing the types of secondary current values (for example, two types of the first current value and the second current value) that can be held by the energization control of the coil is provided.

The superimposition control timing determination means 301 includes an ignition signal Si, a main primary coil voltage signal, a superimposition control start condition from the superimposition control start condition storage means 302, and a superimposition control review timing from the superimposition control review timing storage means 306. After the ignition timing IG, which is supplied and the ignition signal Si is turned from ON to OFF, the establishment of the superimposition control start timing satisfying the superimposition control start condition is determined. For example, as shown in the waveform diagram of FIG. 7A, after the capacitance discharge energy (electrical energy stored on the secondary side) is consumed by the ignition timing IG due to the primary current cutoff and the primary voltage rises sharply. , The timing at which the voltage decreases in a short time and reaches the index voltage value is determined as the superimposition control start timing α1. Of course, the superimposition control start condition may be set to a state in which it can be considered that a predetermined period (for example, several tens of μs) that can be regarded as a capacitance discharge has elapsed and the discharge has shifted to an induced discharge.

When the superimposition control timing determination means 301 determines that the superimposition control start timing α1 and issues a superimposition control start instruction to the subprimary coil control means 307, the subprimary coil control means 301 energizes the subprimary coil energization signal Sb1 and the subprimary coil. The signal Sb2 is generated and output to the sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72, respectively. The sub-primary coil energization permission switch 71 and the sub-primary coil energization switch 72, which function as energy superimposition means, execute energization control on the sub-primary coil 111b, and the superimposition magnetic flux according to the energization amount acts on the secondary coil 112, and the secondary coil 112 is secondary. The secondary current is superimposed (see the shaded area in the secondary current waveform of FIG. 7A).

At this time, the secondary primary coil control means 307 brings the value of the secondary current obtained from the secondary current detection signal close to the set secondary current value stored in the set secondary current value storage means 304. PWM control is performed to adjust the pulse width of the coil energization signal Sb2 in multiple stages (for example, 256 stages). For example, when the first current value is stored as the set secondary current value in the set secondary current value storage means 304, the secondary current is held at the first current value by the superimposed magnetic flux generated in the secondary primary coil 111b. The sub-primary coil control means 307 performs the first PWM control for controlling the switching operation of the sub-primary coil energization switch 72 so as to supply the energization pulse to be supplied to the sub-primary coil 111b. Similarly, when the second current value is stored as the set secondary current value in the set secondary current value storage means 304, the secondary current becomes the second current value due to the superimposed magnetic flux generated in the secondary primary coil 111b. The sub-primary coil control means 307 performs the second PWM control for controlling the switching operation of the sub-primary coil energization switch 72 so as to supply the held energization pulse to the sub-primary coil 111b.

When there are three or more types of current values stored in the changeable secondary current value storage means 305, an appropriate superimposed magnetic flux corresponding to each current value is generated in the secondary primary coil 111b. The sub-primary coil control means 301 may be able to perform three or more types of PWM control.

After the superimposition control is started as described above, the superimposition control timing determination means 301 determines the success or failure of the superimposition control review timing α2 stored in the superimposition control review timing storage means 306. The superimposition control review timing is, for example, the timing at which the ignition status monitoring period tx of a predetermined time width elapses from the superimposition control start timing α1, and the discharge path of the spark discharge generated between the discharge electrodes of the ignition coil 20 is the tumble flow in the cylinder. It is used as a timing to determine whether or not it is presumed to be inflated by. Since the ignition status monitoring period tx having an appropriate time width changes depending on the characteristics of the internal combustion engine and the operating environment, for example, the stored contents of the superimposition control review timing storage means 306 can be arbitrarily set by an external superimposition control review timing setting signal. If you can change it to, it will be very convenient.

The superimposition control timing determination means 306 monitors the change in the main primary coil voltage detected by the main primary coil voltage detection means until the superimposition control review timing α2 is established (until the ignition status monitoring period tx elapses). , The secondary current addition condition defined as a state in which it is difficult to maintain the expanded discharge path of the spark discharge generated in the spark plug 20, or the secondary specified as a state in which the discharge path of the spark discharge generated in the spark plug 20 is difficult to inflate. Judge the success or failure of the current reduction condition. Then, when the secondary current addition condition is satisfied, the superimposition control timing determination means 301 instructs the subprimary coil control means 307 to superimpose increase control. When the secondary current reduction condition is satisfied, the superimposition control timing determination means 301 instructs the subprimary coil control means 307 to superimpose reduction control. If neither the secondary current addition condition nor the secondary current reduction condition is satisfied, the superimposition control timing determination means 301 does not give an instruction to the secondary primary coil control means 307.

First, a case where the superimposition control timing determination means 306 determines that the change in the main primary coil voltage satisfies the secondary current addition condition will be described.

As described above, an example of the secondary current addition condition is a state in which the absolute value of the main primary coil voltage rises above the index voltage value, but falls below the index voltage value again. The waveform is generated a predetermined number of times (for example, once) or more during the ignition status monitoring period tx. Of course, also in the ignition device 2 for the internal combustion engine of the second embodiment, the secondary current addition condition is not limited to this example, and an appropriate secondary current addition condition is arbitrarily set according to the characteristics of the internal combustion engine and the like. It doesn't matter. For example, even if a blowout waveform is detected at the initial stage of the ignition status monitoring period tx, if the voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2, between the electrodes of the spark plug 20. Since it can be estimated that the generated spark discharge is in a state of being greatly inflated without being blown out, it is not necessary to increase the secondary current even in such a case, so this should be excluded from the secondary current addition condition. You can do it.

During the ignition status monitoring period tx in which the superimposition control timing determination means 301 monitors changes in the main primary coil voltage to determine the success or failure of the secondary current addition condition, the superimposition control determination timing determination means 301 starts superimposition control. The duty ratio of the secondary primary coil energization signal Sb2 so that the secondary primary coil control means 307 that receives the instruction is maintained at the secondary current of the set secondary current value stored in the set secondary current value storage means 304. PWM control is performed to adjust. For example, if the set secondary current value stored in the set secondary current value storage means 304 is the first current value, the secondary primary coil control means 307 is based on the secondary current detection signal from the secondary current detection means. The sub-primary coil energization signal Sb2 so as to supply the sub-primary coil 111b with an energization pulse that appropriately increases or decreases the superimposed magnetic flux generated in the sub-primary coil 111b in order to bring the obtained actual secondary current value closer to the first current value. The first PWM control for adjusting the duty ratio of the above is performed.

As described above, when the secondary primary coil control means 307 performs the first PWM control, the superimposition control review timing α2 is set in a state where the secondary current is held at the first current value, and the superimposition control timing determination means 301 is secondary. When it is determined that the current addition condition is satisfied, the sub-primary coil control means 307 is instructed to perform superimposition increase control. As a result, the secondary primary coil control means 307 has the set secondary current value stored in the set secondary current value storage means 304 among the changeable secondary current values read from the changeable secondary current value storage means 305. A secondary current value (second current value) higher than (first current value) is set as a new set secondary current value. The secondary current value storage means 304 is overwritten, and the secondary current from the secondary current detecting means is overwritten. In order to bring the actual secondary current value obtained from the current detection signal closer to the second current value, the secondary primary coil 111b is supplied with an energizing pulse that appropriately increases or decreases the superimposed magnetic flux generated in the secondary primary coil 111b. The second PWM control for adjusting the duty ratio of the coil energization signal Sb2 comes to be performed.

That is, by performing the superimposition increase control, the superimposition control is performed in which the secondary current value is changed to a higher second current value than the first current value used as an index during the ignition status monitoring period tx, and the secondary current is held at the second current value. When this happens, a large discharge current will flow so that it will not easily be blown out even with a strong tumble flow generated in the cylinder. Therefore, the spark discharge generated between the electrodes of the spark plug 20 swells greatly without being blown out, and a large flame nucleus can be formed in the cylinder, so that suitable combustion can be realized.

Also in the internal combustion engine ignition device 2 of the second embodiment, the first current value used as the set secondary current value in the superimposition control is the average tumble flow generated during the standard operation of the internal combustion engine to be controlled. The secondary current value when the discharge path is sufficiently expanded without being blown out may be set as an index. Further, the second current value can be determined by using the secondary current value when the discharge path is sufficiently expanded without being blown out by the strong tumble flow generated when the internal combustion engine to be controlled is overloaded. good.

On the other hand, in the ignition cycle performed after the set secondary current value of the set secondary current value storage means 304 is changed from the first current value to the second current value as described above, the waveform diagram of FIG. 7B shows. As shown, when the main primary coil voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2 without the blowout waveform appearing during the ignition status monitoring period tx, the ignition plug 20 Since it is considered that the spark discharge generated between the electrodes is greatly expanded without being blown out, the secondary current addition condition is not satisfied, and the superimposition control timing determination means 301 superimposes on the subprimary coil control means 307. Since the increase control is not instructed, the second current value stored in the set secondary current value storage means 304 is maintained as it is, and the secondary current is held at the second current value by the secondary primary coil control means 307. The second PWM control is continued.

Further, also in the ignition device 2 for an internal combustion engine of the present embodiment, the end timing of the superimposition control performed by the superimposition control means 32 is arbitrary. For example, the timing at which the main primary coil voltage drops to a predetermined superimposition stop reference voltage value is set as the superimposition control end timing β, and when this superimposition control end timing β is reached, the superimposition control timing determination means 301 uses the subprimary coil control means 307. By stopping the superimposition control instruction to (or outputting the superimposition control end instruction), the output of the subprimary coil energization permission signal Sb1 and the subprimary coil energization signal Sb2 by the subprimary coil control means 307 is stopped, and the subprimary coil is stopped. The secondary current superimposition function can be stopped by preventing the superimposition magnetic voltage generated by the 111b from acting on the secondary coil 112. Further, when the elapsed time measured from the ignition timing IG reaches the high current holding time defined as the high current period necessary and sufficient for maintaining stable combustion, the superimposition control end timing β is set and the superimposition control is terminated. You can do it.

Next, a case where the superimposition control timing determination means 306 determines that the change in the main primary coil voltage satisfies the secondary current reduction condition will be described.

As an example of the secondary current reduction condition, as shown in FIG. 8A, the short path holding waveform is such that no voltage rise exceeding the index voltage value is observed even once during the ignition status monitoring period tx. In order to determine the success or failure of this secondary current reduction condition, the superimposition control timing determination means 301 monitors the change in the main primary coil voltage during the ignition status monitoring period tx. Further, in the sub-primary coil control means 307 that has been instructed by the superimposition control determination timing determination means 301 to start the superimposition control, the set secondary current value stored in the set secondary current value storage means 304 is the second current value. If there is, an energization pulse that appropriately increases or decreases the superimposed magnetic flux generated in the sub-primary coil 111b is applied so that the actual secondary current value obtained from the secondary current detection signal from the secondary current detection means approaches the second current value. The second PWM control for adjusting the duty ratio of the secondary primary coil energization signal Sb2 is performed so as to supply the secondary primary coil 111b.

As described above, the superimposition control review timing α2 is set in the state where the secondary current is held at the second current value by the second PWM control by the secondary primary coil control means 307, and the superimposition control timing determination means 301 sets the secondary current reduction condition. When it is determined that the above is satisfied, the sub-primary coil control means 307 is instructed to perform superimposition reduction control. As a result, the secondary primary coil control means 307 has the set secondary current value stored in the set secondary current value storage means 304 among the changeable secondary current values read from the changeable secondary current value storage means 305. A secondary current value (first current value) lower than (second current value) is set as a new set secondary current value. The secondary current value storage means 304 is overwritten, and the secondary current value is overwritten by the secondary current detection means. In order to bring the actual secondary current value obtained from the current detection signal closer to the first current value, the secondary primary coil 111b is supplied with an energizing pulse that appropriately increases or decreases the superimposed magnetic flux generated in the secondary primary coil 111b. The first PWM control for adjusting the duty ratio of the coil energization signal Sb2 is performed.

That is, by performing the superimposition reduction control, the superimposition control is performed in which the primary current value is changed to a lower current value than the second current value used as an index during the ignition status monitoring period tx, and the secondary current is held at the first current value. When this happens, the discharge path swells greatly even with a weak tumble flow generated in the cylinder, and a discharge current that does not blow out will flow. Therefore, the spark discharge generated between the electrodes of the spark plug 20 swells greatly without being blown out, and a large flame nucleus can be formed in the cylinder, so that suitable combustion can be realized.

On the other hand, in the ignition cycle performed after the set secondary current value of the set secondary current value storage means 304 is changed from the second current value to the second current value as described above, the waveform diagram of FIG. 8B shows. As shown, when neither the blow-out waveform nor the short path holding waveform appears during the ignition status monitoring period tx, and the main primary coil voltage rises to a high voltage that greatly exceeds the index voltage value at the superimposition control review timing α2. Since it is considered that the spark discharge generated between the electrodes of the ignition plug 20 is greatly expanded without being blown out, neither the secondary current reduction condition nor the secondary current increase condition is satisfied, and the superimposition control timing determination means 301 Since the superimposition reduction control and superimposition increase control are not instructed to the subprimary coil control means 307, the primary current value stored in the set secondary current value storage means 304 is maintained as it is, and the subprimary current value is maintained as it is. The first PWM control by the coil control means 301 is continuously performed. Then, when the superimposition control end timing β is reached, the superimposition control for holding the secondary current at the first current value ends.

As described above, in the superimposition control means 32 in the ignition device 2 for the internal combustion engine according to the second embodiment, after the superimposition control is started, at the superimposition control review timing α2, the secondary current increase condition and the secondary current decrease condition are satisfied. Based on the success or failure, it is determined whether or not superimposition increase control or superimposition reduction control is necessary, and by executing superimposition increase control or superimposition reduction control as necessary, spark discharge generated between the electrodes of the spark plug 20 can be generated. It swells greatly without being blown out, allowing the formation of large flame nuclei in the cylinder and achieving suitable combustion.

However, in the ignition device 2 for the internal combustion engine of the present embodiment, since the changeable secondary current value storage means 305 stores only two types, the first current value and the second current value, the set secondary current value is stored. When the set secondary current value stored in the means 304 is the second current value, the superimposition increase control cannot be performed even if the secondary current increase condition is satisfied. Similarly, the setting 2 When the set secondary current value stored in the secondary current value storage means 304 is the first current value, the superimposition reduction control cannot be performed even if the secondary current reduction condition is satisfied. That is, the internal combustion engine ignition device 2 according to the present embodiment can only control either the superimposition increase control or the superimposition decrease control according to the set secondary current value.

However, there are three or more types of changeable secondary current value storage means 305 (for example, a first current value, a second current value, and a third current value, and the first current value <second current value <third current. If the value) is stored, the superimposition increase control and the superimposition reduction control can be performed more finely, and the set secondary current value stored in the set secondary current value storage means 304 is the upper limit current value (the first). If the intermediate current value (second current value) is neither the third current value) nor the lower limit current value (first current value), the superimposition increase control can be performed when the secondary current increase condition is satisfied, and the secondary current reduction can be performed. When the condition is satisfied, the superimposition reduction control can be performed. That is, if the changeable secondary current value storage means 305 stores three or more types and the sub-primary coil control means 307 can perform PWM control capable of holding the secondary current in three or more types of current values, the establishment condition is satisfied. Depending on the situation, either the superimposition increase control or the superimposition reduction control may be performed.

Further, as in the ignition device 2 for an internal combustion engine of the second embodiment described above, the success or failure of the secondary current increase condition and the secondary current decrease condition is determined within the ignition cycle, and the superposition increase is performed in order to correct within the same cycle. If control or superimposition reduction control is performed, it is possible to eliminate the variation in each ignition cycle and realize stable combustion, but it is not always necessary to judge the success or failure of the secondary current increase condition and the secondary current reduction condition within the same cycle. There is no. For example, if the ignition cycle continues for a predetermined number of times, although the combustion in the cylinder is not hindered, but the tendency of blowout is observed, the superposition increase control is performed assuming that the secondary current increase condition is satisfied, and the cylinder is operated. When the ignition cycle in which the short path holding tendency is observed continues for a predetermined number of times, although it does not hinder the combustion inside, the superimposition reduction control may be performed assuming that the secondary current reduction condition is satisfied.

Although the embodiments of the ignition device for an internal combustion engine according to the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these embodiments, and the configurations described in the claims are provided. As long as it does not change, it may be carried out by diverting known and existing equivalent technical means.

1 Ignition system for internal combustion engine (first embodiment)
10A Ignition coil unit 11A Ignition coil 111 Primary coil 112 Secondary coil 12A Ignition switch 15 Case 20 Spark plug 30A Internal engine drive control device 31 Superimposition control means 40 DC power supply 50 Secondary current stacking means 61 Current detection resistor 62 Secondary current Detection line

Claims (9)

In an ignition device for an internal combustion engine, which applies discharge energy to the secondary side of the ignition coil to cause spark discharge in the spark plug by controlling the energization of the ignition coil by the ignition control means.
A secondary current stacking means that maintains a pre-instructed secondary current value by superimposing a current on the secondary current flowing on the secondary side of the ignition coil.
A primary coil voltage detecting means for detecting the voltage of the primary coil, which reflects the voltage generated in the secondary coil after the ignition timing in the ignition cycle, and
With
When the ignition control means satisfies a predetermined superposition control start condition, the secondary current stacking means is instructed to set a preset secondary current value, so that the secondary current value is set by the secondary current stacking means. Superimposition control is performed to allow the secondary current to flow to the secondary side of the ignition coil, and when the predetermined superimposition control review timing is reached, the change in the primary coil voltage detected by the primary coil voltage detecting means causes a spark discharge generated in the ignition plug. When the secondary current addition condition specified as a state in which it is difficult to maintain the swollen discharge path is satisfied, a current value higher than the currently set secondary current value is set as the new set secondary current value, and a new setting is made. By instructing the secondary current stacking means to indicate the secondary current value, superimposition increase control for causing a secondary current having a higher current value to flow from the secondary current stacking means to the secondary side of the ignition coil, and / or the primary When the change in the primary coil voltage detected by the coil voltage detecting means satisfies the secondary current reduction condition defined as the state in which the discharge path of the spark discharge generated in the ignition plug is difficult to expand, the current set secondary current value is increased. By setting a new set secondary current value to a new set secondary current value and instructing the secondary current stacking means to set a new set secondary current value, the current value is lower from the secondary current stacking means to the secondary side of the ignition coil. An ignition device for an internal combustion engine, which is characterized by performing superimposition reduction control in which a secondary current of a current value is passed. The ignition control means has a predetermined blow-out state, which is a change in the primary coil voltage that is assumed to have caused the spark discharge to blow out from the start of the superposition control to the review timing of the superposition control in one ignition cycle. The ignition device for an internal combustion engine according to claim 1, wherein the occurrence of a number of times or more is used as a secondary current addition condition. The ignition control means is a change in the primary coil voltage on which it is assumed that the short path is maintained without expanding the discharge path of the spark discharge from the start of the superimposition control to the timing of reviewing the superimposition control in one ignition cycle. The ignition device for an internal combustion engine according to claim 1, wherein the continuous short-path holding state is used as a secondary current reduction condition. The secondary current stacking means can maintain a secondary current value at a predetermined first current value and a second current value higher than the first current value.
The ignition control means is characterized in that it performs superimposition increase control only when the set secondary current value is the first current value, and performs superimposition reduction control only when the set secondary current value is the second current value. The ignition device for an internal combustion engine according to any one of claims 1 to 3. In an ignition device for an internal combustion engine, which applies discharge energy to the secondary side of the ignition coil to cause spark discharge in the spark plug by controlling the energization of the ignition coil by the ignition control means.
The ignition coil includes a main primary coil in which the amount of magnetic flux in the forward direction increases when the main primary current is energized and the amount of magnetic flux in the forward direction decreases when the main primary current is cut off, and after the main primary coil is de-energized. By energizing the secondary primary current at an arbitrary timing, the secondary primary coil that generates magnetic flux in the breaking direction opposite to the forward direction and one end side are connected to the ignition plug, and the magnetic flux changes of the main primary coil and the secondary primary coil Suppose it has a secondary coil that acts to give discharge energy.
The main primary coil voltage detecting means for detecting the voltage of the main primary coil, which reflects the voltage generated in the secondary coil after the ignition timing in the ignition cycle,
A secondary current detecting means for detecting the secondary current flowing on the secondary side of the ignition coil, and
Energy superimposition means for superimposing discharge energy on the secondary side of the ignition coil by applying the superimposition magnetic flux in the cutoff direction generated by switching the energization / cutoff of the sub-primary coil to the secondary coil.
With
The ignition control means is preset by adjusting the superimposition magnetic flux generated by the energy superimposition means based on the secondary current value detected by the secondary current detection means when a predetermined superimposition control start condition is satisfied. Superimposition control is performed to flow the secondary current of the set secondary current value to the secondary side of the ignition coil, and when the predetermined superimposition control review timing is reached, the change in the primary coil voltage detected by the primary coil voltage detecting means is changed. , When the secondary current addition condition specified as a state in which it is difficult to maintain the swollen discharge path of the spark discharge generated in the ignition plug is satisfied, a current value higher than the currently set secondary current value is newly set as the secondary current. By setting the value and adjusting the superimposition magnetic flux generated by the energy superimposing means, superimposition increase control for causing a secondary current having a higher current value to flow to the secondary side of the ignition coil, and / or the primary coil voltage The change in the primary coil voltage detected by the detection means is lower than the currently set secondary current value when the secondary current reduction condition defined as the state in which the discharge path of the spark discharge generated in the ignition plug is difficult to expand is satisfied. By setting the secondary current value to a new setting secondary current value and adjusting the superimposed magnetic flux generated by the energy superimposing means, superimposition in which a secondary current having a lower current value flows to the secondary side of the ignition coil. An ignition device for an internal combustion engine, which is characterized by performing reduction control. The ignition control means has a predetermined blow-out state, which is a change in the primary coil voltage that is assumed to have caused the spark discharge to blow out from the start of the superposition control to the review timing of the superposition control in one ignition cycle. The ignition device for an internal combustion engine according to claim 5, wherein the occurrence of a number of times or more is used as a secondary current addition condition. The ignition control means is a change in the primary coil voltage on which it is assumed that the short path is maintained without expanding the discharge path of the spark discharge from the start of the superimposition control to the timing of reviewing the superimposition control in one ignition cycle. The ignition device for an internal combustion engine according to claim 5, wherein the continuous short-path holding state is used as a secondary current reduction condition. The energy superimposition means can adjust the superimposition magnetic flux generated in the sub-primary coil by changing the duty ratio of the power supply pulse supplied to the sub-primary coil.
The ignition control means according to any one of claims 5 to 7, wherein the secondary current is increased or decreased by PWM control for instructing the energy superimposing means to turn on / off the energization. The ignition device for an internal combustion engine described. The ignition control means can set a predetermined first current value and a predetermined second current value higher than the first current value as a set secondary current value, and the set secondary current value is the first. The ignition device for an internal combustion engine according to claim 8, wherein the superimposition increase control is performed only when the current value is high, and the superimposition reduction control is performed only when the set secondary current value is the second current value.

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