WO2020121375A1

WO2020121375A1 - Ignition device for internal combustion engine

Info

Publication number: WO2020121375A1
Application number: PCT/JP2018/045297
Authority: WO
Inventors: 義文内勢
Original assignee: 日立オートモティブシステムズ阪神株式会社
Priority date: 2018-12-10
Filing date: 2018-12-10
Publication date: 2020-06-18
Also published as: JPWO2020121375A1; JP6992198B2

Abstract

Provided is an ignition device for an internal combustion engine with which it is possible to build in an automatic control function for improving the ignition performance of an ignition plug, without an increase in size or cost.　An ignition device 1 for an internal combustion engine, which employs a superimposed magnetic flux generated by means of energization of an auxiliary primary coil 111b to increase a change in magnetic flux after energization of a main ignition coil 111a has been shut off, thereby increasing a discharge energy applied to a secondary coil 112, is provided with: a superimposition switch 14 capable of controlling the amount of flow of a superimposed current I1b; and a superimposition control means 15 for instructing the superimposition switch 14 in such a way as to achieve an amount of flow of the superimposed current I1b suitable for improving the ignition performance.

Description

Ignition device for internal combustion engine

The present invention relates to an ignition device for an internal combustion engine mounted on a motor vehicle, and more particularly to improvement of an ignition device for an internal combustion engine that uses a plurality of primary coils to cause a discharge in an ignition plug.

As internal combustion engines installed in vehicles, direct injection engines and high EGR engines are used to improve fuel efficiency, but these engines do not have very good ignitability, so a high energy type ignition device is required. Become. Therefore, in addition to applying discharge energy from the ignition coil primary side to the ignition coil secondary side based on the classical current cutoff principle, overlapping discharge that increases the energy applied to the secondary side by energizing another primary coil is superimposed. The present inventor has proposed a type ignition device. (For example, refer to Patent Document 1).

The ignition device described in Patent Document 1 causes a dielectric breakdown in the discharge gap of the ignition plug by a high voltage of several Kv generated on the secondary side by cutting off the primary current of the ignition coil, and the secondary side of the ignition coil. After the discharge current is started to flow to, another primary coil is supplied with the primary current. The direction of the magnetic flux generated by energizing the other primary coil is the same as the direction in which the magnetic flux decreases when the primary coil is de-energized. Therefore, the change in the magnetic flux of the primary coil due to the interruption of energization and the generated magnetic flux due to the energization of the other primary coil act on the secondary coil. That is, since the magnetic flux change larger than the magnetic flux change due to the usual primary current interruption acts on the secondary coil, the magnetic flux generated on the secondary side can be accelerated and the secondary current can be superimposed. In fact, according to the overlapping discharge type ignition device, since a relatively large amount of discharge energy can be obtained from the spark plug, the ignitability of the fuel is improved, and the fuel consumption is also improved.

However, the lap discharge type ignition device described in Patent Document 1 can adjust the superimposed energy to be given to the secondary side by changing the amount of electricity or the duration of electricity to the other primary coil, but the adjustment is automatically performed. It does not have the function to do. For example, if the current flowing through the other primary coil is adjusted by feedback control so that a desired current flows, the energization control over the other primary coil can be automatically optimized. Also, by performing feedback control so as to keep the secondary current suitable by increasing or decreasing the current flowing through the other primary coil depending on the state of the secondary current, another primary The energization control to the coil can be automatically optimized.

However, when such an automatic control function is implemented in an internal combustion engine ignition device, there arise problems that the control unit becomes large and the device itself becomes expensive. If the control unit becomes large, it becomes necessary to separately secure a mounting place in a narrow vehicle, and therefore it may be necessary to review the design of the vehicle body. Further, if the cost of the control unit becomes high, the vehicle price must be raised accordingly, and there is a possibility that the market competitiveness cannot be secured.

On the other hand, if the ON/OFF control of the current flowing through the other primary coil is performed by the switching operation of the semiconductor switch element, the control unit can be simplified and cost reduction effects can be expected. However, when a high-voltage semiconductor switching element performs a high-speed switching operation, a large amount of noise is generated because the currents flowing through the two primary coils change abruptly when the switch is turned off. For this reason, a noise reduction function is required such as gradual change in the current flowing through the other primary coil, resulting in a problem that the entire control circuit becomes large.

Therefore, the present invention is an ignition device for an internal combustion engine in which an automatic control function capable of sufficiently improving the ignitability due to the spark discharge generated in the spark plug and suppressing the generation of noise can be mounted without increasing the size and cost. For the purpose of providing.

In order to solve the above-mentioned problems, the internal combustion engine ignition device applies the discharge energy to the secondary side of the ignition coil by controlling the energization of the ignition coil by turning on/off the ignition signal from the ignition control means. In an ignition device for an internal combustion engine that causes a spark discharge in a spark plug, the ignition coil increases the amount of magnetic flux in the forward direction due to energization of a main primary current when the ignition signal is turned on, and the ignition signal is turned off. By cutting the primary current, the amount of magnetic flux in the forward direction decreases, and by passing the superimposed current within the discharge period after the interruption of the power supply to the main primary coil, the magnetic flux is cut in the direction opposite to the forward direction. A secondary primary coil to be generated, and a secondary coil whose one end side is connected to an ignition plug and a magnetic flux change of the primary primary coil and the secondary primary coil acts to give discharge energy, and to the secondary primary coil A sub-primary coil energizing means for changing the amount of magnetic flux in the interruption direction by performing energization/interruption and changing the energization amount to the sub-primary coil, and the sub-primary coil energization means after energization interruption to the main primary coil. And a superimposing control means for controlling the energization amount by the sub-primary coil energizing means so that the superimposing current supply to the sub-primary coil is not suddenly cut off.

Further, in the above ignition device for an internal combustion engine, the sub-primary coil energizing means is an active element that increases or decreases the amount of energization to the sub-primary coil according to an input signal.

Further, in the above ignition device for an internal combustion engine, the superimposing control means operates the sub-primary coil energizing means at the same time when the main primary coil is de-energized to start the superimposing current supply to the sub-primary coil, An active signal for holding the superposed current at a required value is sent to the sub-primary coil energizing means for active operation.

Further, in the above ignition device for an internal combustion engine, the superimposing control means operates the sub-primary coil energizing means at the same time when the main primary coil is de-energized to start the superimposing current supply to the sub-primary coil, It is characterized in that an active signal for increasing the superimposed current with the passage of time is sent to the sub-primary coil energizing means for active operation.

Further, in the above ignition device for an internal combustion engine, the superposition control means includes a capacitor that short-circuits an electric charge when an ignition signal is turned on, and starts charging at the start of discharge when the ignition signal is turned off. It is characterized in that the superposition current is controlled to increase with the lapse of time by using the charge accumulation state of 1 as an index.

Further, in the internal combustion engine ignition device, the secondary current detection means for detecting a secondary current flowing on the secondary side of the ignition coil, and the detection value of the secondary current detection means satisfy a predetermined superimposition promotion condition. Based on this, a superimposition promoting unit that promotes an increase in the superimposing current by the superimposing control unit is provided.

Further, in the above ignition device for an internal combustion engine, the superposition promoting means is a secondary current detection value detected by the secondary current detecting means, and an index for promoting an increase in the superposition current for maintaining the secondary current. Is compared with a predetermined increase promotion reference value, and the fact that the detected secondary current value does not exceed the increase promotion reference value is used as the superposition promotion condition.

In the ignition device for an internal combustion engine, a primary coil voltage detecting means for detecting a voltage at a contact point between the main primary coil and the main primary coil energizing switch means, and a primary coil detected by the primary coil voltage detecting means. A superposition suppression condition determination means for determining whether or not the superposition suppression condition is satisfied depending on whether or not the voltage value has reached a primary coil voltage determination reference value determined corresponding to a discharge condition in the spark plug, and the superposition The control means operates the sub-primary coil energizing means at the same time when the energization of the main primary coil is cut off to start the supply of the superimposed current to the sub-primary coil, and the superposition suppressing condition determination means establishes the superposition suppressing condition. When the determination is made, an active signal for suppressing the superimposed current is sent to the sub-primary coil energizing means for active operation.

According to the internal combustion engine ignition device having the above-described configuration, the superimposing control means controls the energization amount by the sub-primary coil energizing means so that the superimposing current supply to the sub-primary coil is not suddenly interrupted, so that the superimposing current supply is stopped. The noise that sometimes occurs can be suppressed.

1 is a schematic configuration diagram of an internal combustion engine ignition device according to a first embodiment. It is a circuit diagram which shows an example of a filter means. FIG. 3 is a waveform diagram showing waveforms in a main part of the internal combustion engine ignition device according to the first embodiment. It is a schematic block diagram of the internal combustion engine ignition device which concerns on 2nd Embodiment. It is a wave form diagram showing a wave form in an important section of an internal-combustion-engine ignition device concerning a 2nd embodiment. It is a schematic block diagram of the internal combustion engine ignition device which concerns on 3rd Embodiment. It is a wave form diagram showing the wave form in the important section of the internal-combustion-engine ignition device concerning a 3rd embodiment. It is a schematic block diagram of the internal combustion engine ignition device which concerns on 4th Embodiment. It is a wave form diagram showing the wave form in the important section of the internal-combustion-engine ignition device concerning a 4th embodiment.

Next, the internal combustion engine ignition device 1A according to the first embodiment will be described in detail with reference to the accompanying drawings.

An ignition device 1A for an internal combustion engine shown in FIG. 1 includes an ignition coil unit 10A for generating a spark at one spark plug 2 provided for each cylinder of the internal combustion engine, and an ignition signal Si for instructing an operation timing of the ignition coil unit 10A. The internal combustion engine drive control device 3 as an ignition control means for outputting the above, etc. at an appropriate timing, a DC power source 4 such as a vehicle battery, and the like. Although the ignition coil unit 10 can exhibit a high noise suppressing effect, the noise removing filter means 5 may be provided in the power supply path for safety. An example of the filter means 5 is an L-type filter (see FIG. 2) in which an inductor 51 is inserted in a power supply line and an electrolytic capacitor 52 is provided in a short circuit with a ground line. If the mounting space can be secured inside the ignition coil unit 10, the filter means 5 may be provided inside the ignition coil unit 10.

The ignition coil unit 10A is a unit having an integrated structure in which the ignition coil 11, the control board, and the like are housed in a case 12 having a required shape. A high-voltage terminal 121 and a connector 122 are provided at appropriate places of the case 12, and the ignition plug 2 is connected via the high-voltage terminal 121, and the internal combustion engine drive control device 3, the DC power source 4, and the ground are connected via the connector 122. Connect with lines, etc.

The ignition coil 11 efficiently causes the magnetic flux generated in the main primary coil 111a (for example, 114 turns) and the sub primary coil 111b (for example, 20 turns) to act on the secondary coil 112 (for example, 9348 turns). For example, the main primary coil 111a and the sub primary coil 111b are arranged so as to surround the center core 113 formed of a highly magnetic permeable material, and the secondary coil 112 is further arranged outside thereof.

One end of the main primary coil 111a is connected to the DC power source 4 via the connector 122, and the power source voltage VB+ (for example, 12V) is applied. The other end of the main primary coil 111a is connected to the collector of the ignition switch 13 using an IGBT (Insulated Gate Bipolar Transistor). The emitter of the ignition switch 13 is connected to the ground point GND via the connector 122. One end of the secondary coil 112 is connected to the ignition plug 2 via the high voltage terminal 121, and the other end is connected to the ground point GND via the fifth connection terminal 122e of the connector 122. A rectifying element D1 (for example, a cathode on the ground side is connected to the Diodes each having an anode connected thereto are provided on the side of the secondary coil 112 to regulate the flow direction of the secondary current I2.

The ignition signal Si output from the internal combustion engine drive controller 3 at an appropriate timing of the discharge cycle is input to the gate of the ignition switch 13 in the ignition coil unit 10A via the connector 122. Then, when the ignition signal Si is input to the gate of the ignition switch 13 (for example, when the signal level of the ignition signal Si changes from L to H), the ignition switch 13 is turned on and the main primary coil 111a on the non-power supply side. The end is connected to the ground point GND. As a result, the main primary current I1a (hereinafter referred to as the primary current) from the power supply side to the ground side starts to flow in the main primary coil 111a, the flow rate of the primary current I1a increases, and the flow rate of the primary current I1a changes. The magnetic flux amount of the energized magnetic flux generated as a result is accumulated as the energy of the magnetic field. It should be noted that on the secondary side of the ignition coil 11, electric energy is accumulated due to minute capacitor components such as the secondary coil 112 and connection wiring.

After the energy is accumulated as described above, when the power supply to the main primary coil 111a is cut off at a predetermined ignition timing, a high-voltage electromotive force is generated in the secondary coil 112 and a spark is generated between the discharge gaps of the spark plug 2. Electric discharge occurs and ignites the mixture in the cylinder combustion chamber. At this time, a counter electromotive force is generated in the main primary coil 111a to flow a current in a direction opposite to the normal primary current I1a. If this counter electromotive force is applied between the collector and the emitter of the ignition switch 13, there is a risk that the ignition switch 13 will malfunction or the deterioration of the ignition switch 13 will be accelerated. Therefore, a bypass line L1 is provided in parallel with the ignition switch 13, and a rectifying element D2 (for example, a cathode on the collector side of the ignition switch 13 is provided in the forward direction from the ground point side of the bypass line L1 toward the ignition coil 11 side). , Diodes having anodes respectively connected to the emitter side of the ignition switch 13 are provided.

On the other hand, similarly to the main primary coil 111a, the sub primary coil 111b capable of exerting a magnetic field on the secondary coil 112 via the iron core 113 has one end connected to the DC power source 4 via the connector 122, The power supply voltage VB+ (for example, 12V) is applied. That is, the main primary coil 111a and the sub primary coil 111b share a power source. The other end of the sub primary coil 111b is connected to the collector of the superposition switch 14 as sub primary coil energizing means using an IGBT. The emitter of the superposition switch 14 is connected to the ground point GND via the connector 122. The superposition switch 14 is an active element that increases/decreases the current between the collector and the emitter in accordance with an input signal to the gate, and increases/decreases the amount of electricity supplied to the sub primary coil 111b by a gate signal from the superposition control means 15A described later.

The superposition switch 14 energizes and cuts off the sub-primary coil 111b, and changes the energization amount to the sub-primary coil 111b, so that the superposition magnetic flux generated in the shut-off direction (the direction in which the energized magnetic flux of the main primary coil 111a is reduced). The amount of magnetic flux can be changed. A rectifying element D3 is provided between the sub primary coil 111b and the superposition switch 14. The rectifying element D3 is provided so as to be in the forward direction from the sub primary coil 111b toward the superposition switch 14 (for example, the cathode of the diode is connected to the superposition switch 14 side and the anode is connected to the sub primary coil 111b side). As a result, the flow direction of the sub-primary current I1b (hereinafter referred to as the superimposed current) is regulated, and it is possible to prevent the reverse voltage from being applied to the superimposed switch 14.

The active operation of the superposition switch 14 is performed by a signal (gate signal) output from the superposition control means 15A that operates based on the superposition signal Sp from the internal combustion engine drive control device 3. The superposition control means 15A immediately operates the superposition switch 14 by receiving the superposition signal Sp (for example, the signal level changes from L to H) at the same time when the main primary coil 111a is de-energized, and the sub primary coil is operated. The supply of the superimposed current to 111b is started. Then, even if the superimposition signal Sp is stopped (for example, the signal level changes from H to L), the superimposition switch 14 supplies the sub-primary current I1b so that the supply of the superimposition current to the sub-primary coil 111b is not suddenly cut off. The amount is controlled to suppress the generation of noise. Since the superposition control means 15A uses the flow rate of the superposition current I1b, the superposition current detection means is provided. For example, a resistor R1 is inserted in a flow path from the superposition switch 14 to the connector 122, and the voltage change is acquired by the superposition current detection signal line L2, thereby forming a superposition current detection unit.

Next, the circuit of the superposition control means 15A will be described. The first comparator 151 has an operational amplifier structure and can obtain an output Vout according to the difference between the non-inverting input (Vin(+)) and the inverting input (Vin(−)). The non-inverting input of the comparator 151 is connected to the superimposed current detection signal line L2, and a signal reflecting the flow rate change of the superimposed current I1b is input. The reference value input line L3 is connected to the inverting input of the comparator 151, and a signal serving as an index of the superposition current I1b suitable for superposition control is input.

The output Vout of the comparator 151 is input to the base of the limiting switch 152 (for example, composed of npn type transistors), and controls the collector current of the limiting switch 152. The collector side of the limiting switch 152 is connected to the superimposed power supply line L4 to which the superimposed signal Sp is input, and the emitter is connected to the ground line. A resistor R2 is interposed between the superposed power supply line L4 and the connector 122, and the superposed power supply line L4 has a superposed power potential reduced by the resistor R2, and this superposed power potential of the limiting switch 152. Applied between collector and emitter.

The superimposed power supply line L4 is connected to one electrode of the first capacitor C1 and the other electrode of the first capacitor C1 is connected to the ground line. That is, when the superposition signal Sp is input to the ignition coil unit 10A, the first capacitor C1 is charged by the superposition power supply supplied from the superposition power supply line L4. An active control signal line L5 is connected to the superimposed power supply line L4, and this active control signal line L5 is connected to the gate of the superimposed switch 14 via a resistor R3. Therefore, when the superposition signal Sp is input to the ignition coil unit 10A, a voltage according to the accumulated charge of the first capacitor C1 is applied to the active control signal line L5, and the active control signal is input to the gate of the superposition switch 14. .. That is, the superposition switch 14 can be activated by the active control signal (gate current) output from the superposition control means 15A, and the superposition current I1b corresponding to the active control signal can be controlled to flow.

On the other hand, the reference value input to the reference value input line L3 of the first comparator 151 is a voltage signal generated by dividing the power supply voltage VB+ by the resistors R4a and R4b, and is input from the superimposed current detection signal line L2. The voltage value is made to correspond to a suitable value of the superimposed current detection value. Therefore, when the superimposed current detection value based on the superimposed current I1b flowing through the sub primary coil 111b is less than the reference value, the output of the first comparator 151 is off, but when the superimposed current detection value reaches the reference value, An output can be obtained according to the difference between the two values. That is, when the superimposed current I1b is less than the reference amount, the limiting switch 152 does not operate, and when the superimposed current I1a reaches the reference amount, the limiting switch 152 operates and the difference between the reference value and the detected superimposed current value. A collector current corresponding to the current flows. When the limiting switch 152 operates and the collector current flows, the power supply amount from the superimposing power supply line L4 to the first capacitor C1 decreases correspondingly, and the active control input from the active control signal line L5 to the gate of the superimposing switch 14 is performed. The signal also drops. Therefore, the superposition control means 15A suppresses the active control signal (gate current) that activates the superposition switch 14 when the superposition current I1b reaches a required value (a suitable flow rate that can realize a suitable ignition state of the spark plug 2). However, automatic control can be performed so as to reduce the superimposed current I1b.

In the ignition coil unit 10A in the present embodiment, the active control signal output from the superimposition control means 15A that actively controls the superimposition switch 14 is generated according to the accumulated charge of the first capacitor C1 fed from the superimposition power supply line L4. I decided. That is, when the input of the superimposition signal Sp is stopped and the superimposition control is ended, the power supply voltage of the superimposition power supply line L4 is gradually reduced by the discharge of the first capacitor C1, so that the gate current of the superimposition switch 14 is also gradually reduced. However, the superposition switch 14 does not turn off suddenly. Accordingly, when the supply of the superimposed current to the sub-primary coil 111b is stopped, the superimposed switch 14 is suddenly turned off, and the generated noise can be suppressed. In order to further suppress the sudden decrease of the superimposed current I1b, the superimposed current sudden decrease suppressing means 16 may be provided. In the ignition coil unit 10A in the present embodiment, the fourth diode D4 (the anode is on the ground side and the cathode is on the power supply side) is connected to the secondary primary coil return path forming line L6 that short-circuits the VB+ power supply line and the ground line. The superposed current sudden decrease suppressing means 16 having a simple structure is provided.

Next, the circuit operation when the superposition control is not performed and the circuit operation when the superposition control is performed will be described based on FIG. 3 showing waveforms of main parts in the internal combustion engine ignition device 1A.

First, I will explain the ignition cycle without superposition control. When the ignition signal Si is turned on and the ignition switch 13 is operated to start energizing the main primary coil 111a, the primary current I1a starts to flow. After that, when the ignition signal Si is turned off and the power supply to the main primary coil 111a is cut off, discharge energy is given to the secondary coil 112, spark discharge occurs in the ignition plug 2 and the secondary current I2 starts to flow. .. However, since the superposition signal Sp is not turned on within the ignition cycle after the ignition signal Si is turned off, the superposition control means 15A does not operate, the superposition switch 14 is also kept off, and the sub-primary coil No discharge energy is superposed on the coil secondary side from 111b.

On the other hand, in the ignition cycle for performing the superposition control, the superposition signal Sp is turned on at the same time as the ignition signal Si is turned off. When the superimposition signal Sp is turned on, charges are accumulated in the first capacitor C1 by the power supply from the superimposition power supply line L4, and an active signal generated at a potential according to the charge accumulation state is superimposed from the active control signal line L5. It is input to the gate of the switch 14. That is, as the accumulated charge of the first capacitor C1 increases, the collector current of the superposition switch 14 also increases, and the flow rate of the superposition current I1b increases at a rate of increase similar to the charging characteristic of the first capacitor C1.

When the superposition signal Sp is turned on, the reference value is input to the inverting input of the first comparator 151 from the reference value input line L3, and the superposition current I1b input to the non-inverting input of the first comparator 151 is input. Since the detected value of is low, there is no output of the first comparator 151. After that, when the charge of the first capacitor C1 progresses and the flow rate of the superimposed current I1b increases, and the detected value of the superimposed current I1b reaches the reference value, the output Vout of the first comparator 151 causes the output Vout of the limiting switch 152 to enter the gate. And the limiting switch 152 is turned on. When the difference between the detected value of the superimposed current I1b and the reference value is small, the collector current of the limiting switch 152 is small and the voltage drop of the superimposed power supply line L4 is small. When the difference between the detected value of the superimposed current I1b and the reference value increases, the collector current of the limiting switch 152 also increases, and the amount of power supplied from the superimposed power supply line L4 to the first capacitor C1 decreases. Therefore, the first capacitor C1 suppresses the charge accumulation speed or discharges as a power source, and the active signal input from the active signal line L5 to the gate of the superposition switch 14 also becomes low. As a result, automatic control is performed to reduce the flow rate of the superimposed current I1b obtained as the collector current of the superimposed switch 14.

After that, when the detected value of the superimposed current I1b falls below the reference value due to the decrease of the superimposed current I1b, the output Vout of the first comparator 151 is stopped and the limiting switch 152 is turned off. When the power supply amount to the first capacitor C1 is restored by turning off the limiting switch 152, the first capacitor C1 is charged, and the active signal input from the active signal line L5 to the gate of the superposition switch 14 is also included. Get higher As a result, automatic control is performed to increase the flow rate of the superimposed current I1b obtained as the collector current of the superimposed switch 14.

In this way, the superposition control means 15A can automatically perform active control of the superposition switch 14 so that the superposition current I1b is maintained at a required value. Therefore, when the internal combustion engine ignition device 1A according to the present embodiment performs the superposition control, the discharge energy applied to the secondary side is superposed by a substantially constant amount, and is a constant amount more than the secondary current I2 when the superposition control is not performed. The secondary current I2 is increased by only (see the waveform of the secondary current I2 in FIG. 3).

Further, in the superimposition control means 15A, even if the superimposition signal Sp is turned off and the superimposition control ends, the active signal is gradually reduced by discharging the first capacitor C1, so that the superimposition switch 14 is not suddenly cut off. Therefore, the noise generated when the superposition switch 14 is turned off can be suppressed. By gradually reducing the active signal in this way, the superimposed current I1b is also gradually reduced (see the waveform of the superimposed current I1b in FIG. 3).

In addition, since the superposition control means 15A can be realized as a circuit board using a discrete component having high heat resistance and noise resistance, it can be stably operated even if it is provided in the ignition coil unit 10A together with the ignition coil 11. Therefore, unlike the case where the function of the superimposition control means 15A is configured as a control device different from the ignition coil unit 10A, it is not necessary to secure a place for mounting the control device in the vehicle, which is also highly practical.

In the internal combustion engine ignition device 1A of the first embodiment described above, the superposition control means 15A sends an active signal for holding the superposition current I1b to a required value to the superposition switch 14 for active operation, resulting in a substantially constant discharge on the secondary side. The superposition control that gives energy is described, but the present invention is not limited to this. For example, it is also possible to perform superposition control in which an active signal for increasing the superposition current I1b with time elapses is sent to the superposition switch 14 to be activated, and discharge energy given to the secondary side with time elapses. In the ignition device for internal combustion engine 1B of the second embodiment shown in FIG. 4, such superposition control is possible. The same components as those of the internal combustion engine ignition device 1A of the first embodiment described above are designated by the same reference numerals, and description thereof will be omitted.

The superposition control means 15B in the internal combustion engine ignition device 1B of the second embodiment is provided with a reference value increase control unit 153. The reference value increase control unit 153 includes, for example, a second capacitor C2 that is charged by the voltage of the reference value input line L3, and a discharge switch 154 that opens and closes a short circuit that short-circuits the reference value input line L3 to ground. To do. Normally, the non-inverting input Vin(+) of the first comparator 151 has a reference value (a voltage obtained by dividing the power supply voltage VB+ by resistors R4a and R4b) serving as an index for limiting the superimposed current I1b from the reference value input line L1. ) Is entered. The second capacitor C2 connected to the reference value input line L3 is charged/discharged according to the potential of the reference value input line L3 (see the first comparator Vin(−) input waveform in FIG. 5). On the other hand, since the ignition signal Si is input to the base of the discharge switch 154 that can be configured by an npn-type bipolar transistor or the like, the reference value input line L3 is shorted to the ground line while the ignition signal Si is on. Therefore, the second capacitor C2 is discharged, and the accumulated charge approaches zero. When the ignition signal Si is turned off, the discharge switch 154 is also turned off, so that the second capacitor C2 is charged with the potential applied to the reference value input line L3 (potential serving as the reference value).

That is, when the electric charge accumulated in the second capacitor C2 becomes zero due to the ignition signal Si being turned on, the potential of the reference value input line L3 becomes zero, and the electric charge is accumulated in the second capacitor C2 with the passage of time. And the potential of the reference value input line L3 rises. It should be noted that due to the charging/discharging characteristics of the second capacitor C2, not all the electric charge is discharged to zero potential while the ignition signal Si is on, and the second capacitor C2 is not equal to the reference value (resistor R4a and resistor R4b). It is not necessary to charge the battery to a steady state where it reaches a voltage according to the pressure ratio), and it is desirable to use it in a range where the linearity of charge accumulation with respect to the passage of time is good.

By changing the reference value according to the charging characteristic of the second capacitor C2, it is possible to gradually increase the superimposed current I1b after starting the supply of the superimposed current to the sub primary coil 111b. In order to do so, the charging characteristic such that the superimposed current detection value is higher than the reference value for a while after the superimposition control is started, and the reference value gradually approaches the superimposed current detection value or changes to exceed the superimposed current detection value. It is necessary to use the second capacitor C2. By changing the reference value in this way, the first comparator 151 determines that the detection value of the superimposed current is higher than the reference value immediately after the superposition signal Sp is turned on and the superposition control is started. When the switch is turned on, the limiting switch 152 is also turned on, and the amount of power supplied to the first capacitor C1 is reduced. Therefore, the charging speed of the first capacitor C1 is slowed down, the active signal serving as the base current of the superimposition switch 14 is suppressed to a low current, and the rate of increase in superimposition current immediately after the start of superimposition is reduced. After that, when the reference value increases and approaches the superimposed current detection value or exceeds the superimposed current detection value, the collector current of the limiting switch 152 decreases or the limiting switch 152 turns off, and power is supplied to the first capacitor C1. The amount recovers. Therefore, the charge storage speed of the first capacitor C1 is increased, the active signal serving as the base current of the superposition switch 14 is also increased to a high current, and the superposition current increase rate is higher than immediately after the start of superposition.

In this way, the superimposing control means 15B can automatically perform active control of the superimposing switch 14 such that the superimposing current I1b is gradually increased. Therefore, when superimposing control is performed by the internal combustion engine ignition device 1B of the present embodiment, immediately after the superimposing control in which high discharge energy is applied from the main primary coil 111a to the secondary side is started, the superimposing current I1b is suppressed to a low level, and the secondary current I1b is reduced. The current I2 can be prevented from becoming too high. After that, when the discharge energy applied from the main primary coil 111a to the secondary side becomes low, the superimposed current I1b can be increased to prevent the secondary current I2 from decreasing (see the waveform of the secondary current I2 in FIG. 5).

In the internal combustion

engine ignition devices

1A and 1B according to the first and second embodiments described above, automatic control is performed so as to obtain a suitable combustion state according to the detection state of the superimposed current I1b. The information used is not particularly limited. For example, the superposition control can be performed according to the detection state of the secondary current I2. Therefore, an internal combustion engine ignition device 1C of the third embodiment that performs superposition control based on the detected state of the secondary current I2 will be described in detail with reference to the accompanying drawings. The same components as those of the internal combustion

engine ignition devices

1A and 1B according to the first and second embodiments described above are designated by the same reference numerals, and description thereof will be omitted.

In the internal combustion engine ignition device 1C of the third embodiment, in order to sufficiently and sufficiently improve the ignitability due to the spark discharge generated in the spark plug 2, a configuration for automatically maintaining the secondary current I2 high is provided. is there. In order to do so, it is necessary to have a function of detecting the secondary current I2 as an index and a function of acting on the superposition switch 14 to promote an increase in the flow rate of the superposition current I1b. In addition, in the internal combustion engine profitable ignition device 1C of the present embodiment, the increase promotion control is the normal time control, and the increase promotion is suppressed only when the increase promotion control is not necessary, but the invention is not limited to this. is not. Normal superimposition control is performed during normal times, and control that promotes an increase in the flow rate of superimposition current I1b is performed only when it is necessary to increase the flow rate to a flow rate higher than the flow rate of superimposition current I1b during normal times. good.

First, the function of detecting the secondary current I2 flowing to the secondary side of the ignition coil 11 (secondary current detection means) is to have a proper flow path for the secondary current I2 (for example, the cathode side of the rectifying element D1 and the ground of the connector 122). It can be configured by a resistor R5 inserted between the terminal) and a secondary current detection signal line L7 that acquires this voltage change. On the other hand, the superposition promoting means 17 is provided as a function of working the superposition switch 14 to promote the flow rate of the superposition current I1b. The superposition promoting means 17 can be realized by various circuit structures, but in the present embodiment, an example in which the second comparator 171 and the superposition promoting switch 172 are used is shown.

The superimposition promoting means 17 promotes an increase in the superimposing current by the superimposition controlling means 15C based on the detection value of the secondary current detecting means satisfying a predetermined superimposing promoting condition. When such control is performed, a superimposition promotion condition is used as a condition for determining whether or not to promote an increase in the superimposition current I1b in order to avoid a state where the secondary current I2 decreases and good ignitability cannot be maintained. Setting is required. For example, when the secondary current I2 is lower than a predetermined reference value during the period of performing the superposition control, if the active signal output from the superposition control means 15C is increased, the superposition switch 14 changes the superposition current I1b. The rate of increase can also be increased. In the present embodiment, when the secondary current I2 is lower than the predetermined reference value, an active signal is output from the superposition control means 15C by the normal superposition control, and when the secondary current I2 becomes equal to or higher than the predetermined reference value, the superposition is performed. The supply of the current I1b is suppressed to limit the superimposed current I1b more than in the normal state.

Therefore, the secondary current detection value (the signal voltage of the secondary current detection signal line L7) detected by the secondary current detection means is input to the non-inverting input Vin(+) of the second comparator 171, and the inverting input Vin(+ Enter the increase promotion reference value in -). The increase promotion reference value is a predetermined value as an index for promoting the increase of the superimposed current in order to maintain the secondary current I2 at or above the reference value, and a voltage value corresponding to the detected secondary current value is used. In the present embodiment, the voltage obtained by dividing the power supply voltage VB+ by the resistors R6a and R6b is used as the increase promotion reference value, and the second voltage is supplied via the increase promotion reference signal line L8 connected between the resistors R6a and R6b. It is input to the inverting input Vin(-) of the comparator 171. In this way, the comparison result between the secondary current detection value and the increase promotion reference value can be obtained as the output Vout of the second comparator 171. The second comparator 171 is assumed to use an open collector type comparator, and the pull-up voltage to which the power supply voltage VB+ is input via the resistor R7 is the H level voltage of the output Vout which becomes the increase promotion condition determination signal Su. Set to.

The increase promotion switch 172 uses, for example, a pnp-type bipolar transistor. The emitter of the increase promoting switch 172 is connected to the DC power supply 4 via the connector 122, and the power supply voltage VB+ is applied. The collector of the increase promotion switch 172 is connected to the reference value input line L3 of the superimposition control means 15C via the increase promotion power supply line L9 through which the resistor R8 is inserted. When the increase promotion switch 172 is turned on and the collector current flows through the increase promotion power supply line L9, the reference value line L3 becomes equal to the state where the power supply line in which the resistor R8 and the resistor R4a are connected in parallel is connected. .. That is, when the increase promotion switch 172 is turned on and the increase promotion power supply line L9 is connected to the reference value line L3, it means that the resistor R8 and the resistor R4a are connected in parallel, and the combined resistance value and the resistance R4b of these resistors are combined. The potential of the reference value line L3 which is the voltage division ratio of

At the normal time when the increase promotion means 17 has not determined that the increase promotion condition is satisfied, the reference value supplied from the reference value line L3 to the second capacitor C2 is a relatively low value determined by the voltage division ratio of the resistors R4a and R4b. is there. However, when the increase promotion means 17 determines that the increase promotion condition is satisfied, the reference value supplied from the reference value line L3 to the second capacitor C2 is the combined resistance of the resistor R8 and the resistor R4a connected in parallel and the resistor R4b. It becomes a relatively high value determined by the partial pressure ratio of. Therefore, when the increase promotion condition is satisfied, the reference value becomes higher than the superimposed current detection value, or the difference between the superimposed current detection value and the reference value is reduced, so that the limiting switch 152 is turned off and the collector current is reduced. Is reduced. As a result, the amount of power supplied to the first capacitor C1 increases, the charge storage speed increases, and the gate current to the superposition switch 14 also increases. As a result, the increase of the superimposed current I1b controlled as the collector current of the superimposed switch 14 can be promoted.

The increase promotion condition determination signal Su, which is the output Vout of the second comparator 171, is input to the base of the increase promotion switch 172 from the operating state instruction line L10 through the resistor R9. When the increase promotion condition determination signal Su from the second comparator 171 is off (the signal level is H), the base current of the increase promotion switch 172 does not flow, so the increase promotion switch 172 is turned off, and the increase promotion supply voltage is increased. Power is not supplied to the superposition control means 15C via the electric wire L9. On the other hand, when the increase promoting condition determination signal Su from the second comparator 171 is turned on (the signal level is L), the base current of the increase promoting switch 172 flows, the increase promoting switch 172 is turned on, and the increase promoting supply is supplied. Power is supplied to the superimposition control means 15C via the electric wire L9.

In the superposition promoting means 17 thus configured, when the increase promoting condition is satisfied, the charge accumulation speed of the second capacitor C2 is increased and the reference value signal line L3 supplies the inverted input Vin(-) of the first comparator 151. The increase of the standard value is promoted. Since the reference value increases early, it becomes easy to exceed the superimposed signal detection value, and the output Vout of the first comparator 151 stops at an early timing. When the output Vout of the first comparator 151 is stopped, the limiting switch 152 is also turned off, the amount of power supplied from the superimposed power supply line L4 to the first capacitor C1 is restored, and the charge storage speed of the first capacitor C1 can be increased. As a result, the active signal, which is the gate current for actively controlling the superposition switch 14, is also increased, and the increase of the superposition current I1b is promoted. That is, since the superposed magnetic flux generated in the sub primary coil 111b increases and the magnetic flux change acting on the secondary coil 112 increases, the electromotive force on the secondary side of the ignition coil is increased and the secondary current I2 is maintained at a high value. Is possible.

On the other hand, when the increase promotion condition is not satisfied, the superimposition promotion means 17 remains off and power is not supplied from the increase promotion power supply line L9 to the reference signal line L3. Therefore, the charge storage speed of the second capacitor C2 is not increased, and thus the charge storage speed of the first capacitor C1 is not increased. After that, when the secondary current I2 becomes low by not performing the increase promotion control and the increase promotion condition is satisfied, the superimposition promoting means 17 supplies power to the superimposition controlling means 15C from the increase promoting power supply line L9 to obtain the reference value. Promote the increase of. That is, even if the secondary current I2 decreases without performing the superposition promotion control by the superposition promotion means 17, if the increase promotion condition is satisfied again, the superposition promotion means 17 will perform the superposition promotion control again, and the secondary promotion. It is possible to automatically increase the current I2 and keep the secondary current I2 at a high value.

Next, the circuit operation when the superposition control is not performed and the circuit operation when the superposition control is performed will be described based on FIG. 7 showing waveforms of main parts in the internal combustion engine ignition device 1C.

First, I will explain the ignition cycle without superposition control. Since the increase promotion condition is satisfied before the ignition signal Si is turned on, power is supplied from the superposition increasing means 17 through the increase promotion power supply line L9, and the second capacitor C2 is in a steady state in which electric charge is accumulated. It is in a state. When the ignition signal Si is turned on and the ignition switch 13 is operated to start energizing the main primary coil 111a, the primary current I1a starts to flow. When the ignition signal Si is turned on, the discharge switch 154 is turned on, the electric charge of the second capacitor C2 is short-circuited, and the input potential of the non-inverting input Vin(+) of the first comparator 151 falls to L. However, since the superimposed current I1b does not flow at this time, the non-inverting input Vin(+) of the first comparator 151 also remains L, so the output Vout of the first comparator 151 is also L, and the limiting switch The 152 does not operate.

After that, when the ignition signal Si is turned off and the power supply to the main primary coil 111a is cut off, discharge energy is given to the secondary coil 112, spark discharge occurs in the ignition plug 2 and the secondary current I2 starts to flow. .. When the ignition signal Si is turned off, the discharging switch 154 is turned off and the charging of the second capacitor C2 is started. At this time, a high secondary current I2 flows due to capacitive discharge immediately after the start of discharge, and when the increase promotion reference value is exceeded, the increase promotion condition is no longer satisfied, and the superposition control means is provided from the increase promotion means 17 via the increase promotion power supply line L9. Power is not supplied to 15C. Therefore, the second capacitor C2 of the superposition control means 15C is charged only by the power source supplied via the resistor R4a.

When the secondary current I2 decreases and falls below the increase promotion reference value, the increase promotion condition is satisfied again, so that power is supplied from the increase promotion means 17 to the superposition control means 15C via the increase promotion power supply line L9. Become. Therefore, the second capacitor C2 of the superimposition control means 15C is charged by the parallel power supply including the power supply supplied via the resistor R4a and the power supply supplied via the increase promoting power supply line L9, and the charge storage speed is accelerated. To be done. However, when the superposition control is not performed, the superposition signal Sp is not input, so that the first capacitor C1 is not charged and the active signal is not output to the superposition switch 14. Therefore, after starting the discharge of the ignition plug 2, energy is not applied to the secondary side of the ignition coil in a superimposed manner, and the secondary current I2 also decreases as the forward magnetic flux in the main primary coil 111a decreases.

On the other hand, in the ignition cycle for performing the superposition control, the superposition signal Sp is turned on at the same time as the ignition signal Si is turned off. When the superimposition signal Sp is turned on, power is supplied from the superimposition power supply line L4 to start charging the first capacitor C1. When an active signal having a flow rate according to the charge charged in the first capacitor C1 is input to the gate of the superposition switch 14, the superposed current I1b starts to flow in the sub primary coil 111b, and the amount of accumulated charge in the first capacitor C1 continues thereafter. Accordingly, the flow rate of the superimposed current I1b increases.

Immediately after the start of discharge, the secondary current I2 is so high that the increase promotion condition is no longer satisfied, and power is no longer supplied from the increase promotion means 17 to the superposition control means 15C via the increase promotion power supply line L9. Therefore, the second capacitor C2 of the superimposition control means 15C is charged only by the power source supplied via the resistor R4a, and the increasing speed of the reference value input to the inverting input of the first comparator 151 is not promoted. It does not rise easily. If the reference value is a relatively low value, the superimposed current detection value is likely to be higher, and therefore the first comparator 151 is turned on and the limiting switch 152 is easily turned on. When the limiting switch 152 is turned on and the collector current flows, the amount of power supplied to the first capacitor C1 decreases, the active signal supplied to the superposition switch 14 also decreases, and the superposition current I1b flowing to the sub primary coil 111b increases. The speed will be slightly lower. As described above, when the increase promoting condition is not satisfied, the increasing rate of the superimposed current I1b flowing through the sub primary coil 111b is reduced, so that the secondary current I2 can be prevented from becoming higher than necessary.

When the secondary current I2 decreases and falls below the increase promotion reference value, the increase promotion condition is satisfied again, so that power is supplied from the increase promotion means 17 to the superposition control means 15C via the increase promotion power supply line L9. Become. Therefore, the second capacitor C2 of the superimposition control means 15C is charged by the parallel power supply including the power supply supplied via the resistor R4a and the power supply supplied via the increase promoting power supply line L9. As the charge storage speed of the second capacitor C2 increases, the reference value input to the inverting input of the first comparator 151 also increases in speed, so that the reference value reaches the superimposed current detection value at an early timing and the first comparison The output of the device 151 is turned off, and the limiting switch 152 is also turned off. When the limiting switch 152 is turned off, the amount of power supplied from the superimposed power supply line L4 to the first capacitor C1 is recovered and the charge storage speed is increased, so that the increase of the superimposed current I1b flowing through the sub primary coil 111b is promoted. be able to. In this way, when the increase promotion condition is satisfied, the increase of the superimposed current I1b flowing through the sub primary coil 111b is promoted, so that the secondary current I2 can be suppressed from becoming lower than the reference value.

When the control for promoting the increase of the superimposed current I1b or returning it to the normal increasing state by using the superposition promoting means 17 as described above, the amount of change in the magnetic flux acting on the secondary coil 112 can be preferably held. Therefore, the electromotive voltage generated on the secondary side can be maintained high. That is, according to the internal combustion engine ignition device 1C of the present embodiment, in order to sufficiently and sufficiently improve the ignitability due to the spark discharge generated in the spark plug 2, the secondary current I2 is maintained at a high value, but is excessively increased. It is possible to suppress an increase in the power consumption by increasing the secondary current I2. Moreover, the superimposition promoting means 17 can be constructed at a relatively low cost and in a small size by using discrete components such as the second comparator 171 and the increase promoting switch 172.

In the internal combustion engine ignition devices 1A to 1C of the first to third embodiments described above, automatic control is performed so as to obtain a suitable combustion state according to the detection states of the superimposed current I1b and the secondary current I2. However, the information used for automatic control is not limited to the current value. For example, if the superposition control is performed using the secondary coil voltage applied to the spark plug 2, it is possible to perform appropriate ignition control according to the discharge state of the spark plug 2.

In the first place, in order to improve the ignitability in a direct injection engine or a high EGR engine, it is not enough to lengthen the high current period, and it is also important to form a large flame by the discharge current of the spark plug 2. is there. In a normal engine, the flow velocity of the tumble flow generated in the cylinder is about 3 to 5 [m/s], while an engine that attempts to burn with ultra lean lean combustion (A/F=29) or EGR=35% Then, the flow velocity of the tumble flow generated in the cylinder increases to about 20 [m/s]. In the cylinder in which the flow velocity has increased in this way, the spark discharge generated in the spark plug 2 is swept by the tumble flow and swells, and the discharge path extends. When the discharge path of the spark discharge generated in the spark plug 2 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 2 extends, the discharge path cannot be maintained unless a sufficient discharge current flows, and a new discharge path connecting the electrodes of the spark plug with a short path is formed. It causes a restructuring (discharging of discharge) that occurs, and a flame kernel of a sufficient size cannot be formed. Therefore, in order to improve the ignitability of the direct injection engine or the high EGR engine, it is important to prevent the retriggering of the spark discharge generated in the spark plug 2. For this reason, when the secondary coil voltage is equal to or higher than the predetermined reference value (or higher), the discharge energy to the secondary side is increased and the secondary coil voltage does not reach the reference value (or When it is less than the reference value), the control for suppressing the secondary side discharge energy is effective.

However, 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 leakage due to the provision of the voltage dividing resistor. It is not realistic to do.

Therefore, in the internal combustion engine ignition device 1D according to the fourth embodiment, the voltage detection value of the main primary coil 111a that generates a voltage according to the turn ratio with the secondary coil 112 is estimated as the secondary coil voltage detection value. The superposition control is performed. Since the voltage generated in the main primary coil 111a (hereinafter referred to as the primary coil voltage) has a relatively low voltage value, the difficulty of monitoring is low. However, the primary coil voltage and the secondary coil voltage have different scales of voltage values and have opposite polarities. Based on this difference, the primary coil voltage can be treated as the correlation information of the secondary coil voltage.

Hereinafter, an internal combustion engine ignition device 1D according to a fourth embodiment will be described in detail with reference to the accompanying drawings. The same components as those of the internal combustion engine ignition devices 1A to 1C according to the first to third embodiments described above are designated by the same reference numerals, and description thereof will be omitted.

In the ignition coil unit 10D of the internal combustion engine ignition device 1D of the fourth embodiment, in order to detect the low-voltage side voltage of the main primary coil 111a, between the main primary coil 111a and the ignition switch 13 (for example, the bypass line L1. (The same position as) and the primary coil voltage detection line L11 is branched to lead to the primary coil voltage detection means 18. In the primary coil voltage detection means 18, the position coil voltage input from the primary coil voltage detection line L11 is stepped down by the resistor R9, and a resistor R10 for voltage detection is further inserted between the position coil voltage and the ground line. The voltage drop due to the resistor R10 is acquired by the primary coil voltage detection line L12.

The primary coil voltage detection line L12 is connected to the superposition suppression condition determination means 19 and supplies the primary coil voltage detection value as information correlating with the secondary coil voltage. The primary coil voltage detection means 18 is provided with a bypass line L13 that bypasses the primary coil voltage detection line L12 and diverts the current. A Zener diode ZD is connected to the bypass line L13 so as to be reverse biased (cathode on the main primary coil side and anode on the ground side), and the Zener breakdown voltage may be applied to the superposition suppression condition determination means 19. It is set to an undesired regulation voltage value. Thus, when the primary coil voltage becomes abnormally high and reaches the regulated voltage value on the bypass line 13, it is possible to prevent the Zener diode ZD from breakdown and to prevent the regulated voltage from being applied to the primary coil voltage detection line L12. ..

In the ignition coil unit 10D, by estimating the secondary coil voltage based on the detected primary coil voltage, the superposition suppression condition determination means 19 determines whether or not the superposition control is possible based on the change in the voltage applied to the ignition plug 2. For example, the superposition suppression condition determination means 19 determines whether or not the primary coil voltage value detected by the primary coil voltage detection means 18 has reached the primary coil voltage determination reference value determined in correspondence with the discharge condition in the spark plug 2. The success or failure of the superposition suppression condition is determined by. When the superposition suppression condition determination unit 19 determines that the superposition suppression condition is satisfied, the active signal sent from the superposition control unit 15 to the superposition switch 14 is suppressed to suppress the superposition current I1b flowing through the sub-primary coil 111b, resulting in an excess. Prevents discharge energy from being given to the secondary side. On the other hand, when the superposition suppression condition determination unit 19 determines that the superposition suppression condition is not satisfied, the active signal sent from the superposition control unit 15 to the superposition switch 14 is not suppressed, and the superposition current I1b with the full capacity is supplied to the sub primary coil 111b. , Prevents blowout of spark discharge.

The superposition suppression condition determination means 19 for determining success or failure of the superposition suppression condition uses the primary coil voltage detection value input from the primary coil voltage detection means 18 via the primary coil voltage detection line L12 as an inverted input Vin of the third comparator 191. Receive with (-). The primary coil voltage determination reference value is input to the non-inverting input Vin(+) of the third comparator 191 via the determination reference value line L14. The primary coil voltage determination reference value is generated as a constant voltage signal obtained by dividing the power supply voltage VB+ by the resistors R11a and R11b.

The output Vout of the third comparator 191 is input to the base of the superposition suppressing switch 192 composed of, for example, an npn-type bipolar transistor. The emitter of the superposition suppression switch 192 is connected to the ground line, and the collector is connected to the parallel connection line L15 in which the resistor R12 is inserted. The other end of the parallel connection line L15 is connected to the reference value line L3 of the superposition control means 15D. That is, when the superposition suppressing switch 192 is turned on and the parallel connection line L15 is connected to the ground line, the resistors R12 and R4b are connected in parallel, and the voltage division ratio between the combined resistance value and the resistor R4a is obtained. Then, the potential of the reference value line L3 is decreased.

In a normal state where the superposition suppression condition determination means 19 has not determined that the superposition suppression condition is satisfied, the reference value supplied from the reference value line L3 to the inverting input of the first comparator 151 is the voltage division ratio of the resistors R4a and R4b. It is a relatively high value determined by. However, when the superposition suppression condition determination unit 19 determines that the superposition suppression condition is satisfied, the reference value supplied from the reference value line L3 to the inverting input of the first comparator 151 is the resistance R12 and the resistance R4b connected in parallel. It becomes a relatively low value determined by the voltage division ratio of the combined resistance of R1 and the resistance R4a. Therefore, when the superposition suppression condition is satisfied, the reference value becomes lower than the superposition current detection value, the limiting switch 152 is turned on, and the collector current flows, so that the amount of power supply to the first capacitor C1 decreases. The charge accumulation is suppressed, and the gate current to the superposition switch 14 also decreases. As a result, the superimposed current I1b controlled as the collector current of the superimposed switch 14 is suppressed.

Next, the circuit operation when the superposition suppression control is not performed and the circuit operation when the superposition suppression control is performed will be described based on FIG. 9 showing waveforms of main parts in the internal combustion engine ignition device 1D.

First, I will explain the ignition cycle without superposition control. Before the ignition signal Si is turned on, the primary coil voltage is the reference ground potential, and is lower than the primary coil voltage determination reference value set to the value on the negative electrode side. Therefore, the superposition suppression condition is satisfied, and the superposition suppression switch 192 turns on. As a result, the resistor R12 is connected in parallel with the resistor R4b, and the reference value supplied from the reference value line L3 to the inverting input of the first comparator 151 is replaced with a low value. However, since the superposition control is not performed, the output Vout of the first comparator 151 remains L and the active control signal is not output from the active control signal line L5 to the superposition switch 14. When the ignition signal Si is turned on and the ignition switch 13 is operated to start energizing the main primary coil 111a, the primary current I1a starts to flow. At this time, although the primary coil voltage slightly changes due to the impedance component of the main primary coil 111a itself, since it does not exceed the primary coil voltage determination reference value, the superposition suppression condition remains satisfied, but the superposition control is performed. It will not take place.

After that, when the ignition signal Si is turned off and the power supply to the main primary coil 111a is cut off, discharge energy is given to the secondary coil 112, spark discharge occurs in the ignition plug 2 and the secondary current I2 starts to flow. .. At this time, a high secondary current I2 flows due to capacitive discharge immediately after the start of discharge, and when the primary coil voltage determination reference value exceeds the negative side, the superimposition suppression condition is not satisfied, so the third comparator 191 turns off and superimposes. The suppression switch 192 is also turned off. Therefore, a high voltage corresponding to the voltage division ratio of the resistors R4a and R4b is supplied to the reference value line L3 as a reference value. However, since the superposition control is not performed, the output Vout of the first comparator 151 remains L and the active control signal is not output from the active control signal line L5 to the superposition switch 14.

Immediately after the start of discharge, the secondary current I2 is so high that the superposition suppression condition is no longer satisfied, and the resistance R12 of the parallel connection line L15 is not connected in parallel to the resistance R4b of the superposition control means 15D. Therefore, a high voltage corresponding to the voltage division ratio of the resistors R4a and R4b is supplied to the reference value line L3 as a reference value. When the reference value becomes high, the first comparator 151 is hard to be turned on, the collector current does not flow through the limiting switch 52, and the amount of power supply to the first capacitor C1 is not reduced. As a result, an active signal corresponding to the amount of charge stored in the first capacitor C1 is supplied to the superimposing switch 14, and the superimposing current I1b having the maximum capacity can be passed to the sub-primary coil 111b, and the discharge energy applied to the secondary side is suppressed. It will not be done.

When the secondary current I2 decreases and falls below the primary coil voltage determination reference value, the superposition suppression condition is satisfied again, so that the resistance R12 of the parallel connection line L15 is connected in parallel to the resistance R4b of the superposition control means 15D from the increase promoting means 17. Done. Therefore, a reference value of a relatively low value is supplied to the reference value line L3, the first comparator 151 easily turns on, the limiting switch 52 turns on, and the first capacitor C1 is turned on. Reduce the power supply. When the charge accumulation in the first capacitor C1 is suppressed, the active signal supplied to the superposition switch 14 is also suppressed, so that the superposition current I1b flowing through the sub primary coil 111b is also suppressed. That is, when the primary coil voltage with which the secondary coil voltage can be estimated does not reach the primary coil voltage reference value, it is considered that the flow in the cylinder is small and the spark generated between the electrodes of the spark plug 2 does not extend. It is possible to prevent excessive discharge energy from being applied to the secondary side.

When the primary coil voltage determination reference value is frequently exceeded as in the superposition control 1 shown in FIG. 9, the period for which the superposition suppression condition is satisfied is short, so a large amount of the superposition current I1b is passed for the superposition control. Becomes On the other hand, as in the superposition control 2 shown in FIG. 9, when the primary coil voltage determination reference value rarely exceeds, the superposition suppression condition is satisfied for a long period of time, so the superposition current I1b for the superposition control is suppressed. You can In this way, by performing the superposition suppressing control that does not cause the excessive superposition current I1b to flow to the sub primary coil 111b, it is possible to suppress the excessive energy consumption due to the superposition control. Further, the superposition suppression control can suppress the heat generation of the sub-primary coil 111b, and has an advantage that the control elements such as the ignition switch 13 and the superposition switch 14 can be protected from deterioration and damage due to heat. Moreover, the primary coil voltage detection means 18 and the superposition suppression condition determination means 19 can be constructed relatively inexpensively and small in size with discrete parts having high heat resistance and noise resistance.

The embodiments of the internal combustion engine ignition device according to the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and has the configuration described in the claims. It may be carried out by diverting known existing equivalent technical means within a range where it is not changed.

1A Internal combustion engine ignition device (first embodiment)
10A Ignition coil unit 11 Ignition coil 111a Main primary coil 111b Sub primary coil 112 Secondary coil 13 Ignition switch 14 Superimposition switch 15 Superimposition control means 2 Ignition plug 3 Internal combustion engine drive control device 4 DC power supply

Claims

By controlling the energization of the ignition coil by turning on/off the ignition signal from the ignition control means, in the ignition device for an internal combustion engine, which gives discharge energy to the secondary side of the ignition coil to cause a spark discharge in the ignition plug,
In the ignition coil, the amount of magnetic flux in the forward direction is increased by energizing the main primary current when the ignition signal is turned on, and the amount of magnetic flux in the forward direction is decreased by turning off the ignition signal and shutting off the main primary current. A main primary coil, a sub-primary coil that generates a magnetic flux in a blocking direction opposite to the forward direction by flowing a superimposed current within a discharge period after the interruption of energization to the main primary coil, and one end side is connected to an ignition plug, A secondary coil to which the main primary coil and the change in magnetic flux of the sub primary coil act to give discharge energy,
A sub-primary coil energizing unit that changes the amount of magnetic flux in the interruption direction by performing energization/interruption to the sub-primary coil and changing the amount of energization to the sub-primary coil,
Superposition control means for operating the sub-primary coil energizing means after the main primary coil is de-energized to control the energization amount by the sub-primary coil energizing means so that the supply of superposed current to the sub-primary coil is not suddenly cut off. When,
An ignition device for an internal combustion engine, comprising:
The ignition device for an internal combustion engine according to claim 1, wherein the sub-primary coil energizing means is an active element that increases or decreases the amount of energization to the sub-primary coil according to an input signal.
The superposition control means activates the sub-primary coil energization means at the same time when the main primary coil is de-energized to start the supply of the superposition current to the sub-primary coil, and outputs an active signal for holding the superposition current to a required value. The ignition device for an internal combustion engine according to claim 2, wherein the ignition device is sent to the sub-primary coil energizing means to be actively operated.
The superposition control means activates the sub-primary coil energization means at the same time when the main primary coil is de-energized to start the supply of the superposition current to the sub-primary coil and to increase the superposition current over time. The ignition device for an internal combustion engine according to claim 2, wherein a signal is sent to the sub-primary coil energizing means for active operation.
The superposition control means includes a capacitor that short-circuits the electric charge when the ignition signal is turned on, and starts charging when the ignition signal is turned off, and the charge accumulation state of the capacitor after the start of charging is used as an index. The ignition device for an internal combustion engine according to claim 4, wherein an increase control of the superposed current is performed.
Secondary current detection means for detecting a secondary current flowing on the secondary side of the ignition coil,
A superimposition promoting unit that promotes an increase in the superimposition current by the superimposition control unit based on that the detection value of the secondary current detection unit satisfies a predetermined superposition promotion condition,
The ignition device for an internal combustion engine according to claim 4 or 5, further comprising:
The superposition promoting means compares the secondary current detection value detected by the secondary current detecting means with a predetermined increase promotion reference value as an index for promoting an increase in the superposition current for maintaining the secondary current. The ignition device for an internal combustion engine according to claim 6, wherein the detected secondary current value does not exceed an increase promotion reference value is used as a superposition promotion condition.
A primary coil voltage detecting means for detecting a voltage at a contact point between the main primary coil and the main primary coil energizing switch means,
Whether the primary coil voltage value detected by the primary coil voltage detection means has reached a primary coil voltage determination reference value determined in correspondence with the discharge condition in the spark plug determines whether or not the superposition suppression condition is satisfied. Superimposition suppression condition determining means,
Equipped with
The superposition control means operates the sub-primary coil energization means at the same time when the main primary coil is de-energized to start the superposition current supply to the sub-primary coil, and the superposition suppression condition determination means determines the superposition suppression condition. The ignition device for an internal combustion engine according to claim 2, wherein when it is determined that the condition is satisfied, an active signal that suppresses the superimposed current is sent to the sub-primary coil energizing means to be actively operated.