WO2021064851A1

WO2021064851A1 - Internal combustion engine ignition device

Info

Publication number: WO2021064851A1
Application number: PCT/JP2019/038694
Authority: WO
Inventors: 藤山　幸雄
Original assignee: 日立オートモティブシステムズ阪神株式会社
Priority date: 2019-10-01
Filing date: 2019-10-01
Publication date: 2021-04-08
Also published as: JPWO2021064851A1

Abstract

Provided is an internal combustion engine ignition device that allows superposition discharge using a sub-primary coil to be performed in a stable manner.　In the present invention, an ignition coil unit 10 of an internal combustion engine ignition system 1 comprises: a principal primary coil 111a that is controlled by an ignition signal Si; and an ignition coil 11 in which a sub-primary coil 111b controlled by a superposition signal Sp is provided to the primary side. If an abnormal state detecting means 154 detects an abnormal state where there is a risk that a superposition switch 151 for passing/blocking current to the sub-primary coil 111b cannot operate normally due to heat generation, a heat generation suppressing means 155 suppresses heat generation of the superposition switch 151.

Description

Ignition system for internal combustion engine

The present invention relates to an ignition device for an internal combustion engine mounted on an automatic vehicle, and more particularly to an improvement of an ignition device for an internal combustion engine that causes a spark discharge in a spark plug by using a plurality of primary coils.

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 high-energy ignition devices are required. Become. Therefore, in addition to giving discharge energy from the primary side of the ignition coil to the secondary side of the ignition coil according to the classical current cutoff principle, a layered discharge that energizes another primary coil and superimposes the energy given to the secondary side. A type ignition device has been proposed. (See, for example, Patent Document 1).

The ignition device described in Patent Document 1 causes insulation failure in the discharge gap of the ignition plug due to a high voltage of several kV generated on the secondary side by interrupting the primary current of the ignition coil, and causes insulation failure on the secondary side of the ignition coil. After starting to flow the discharge current to the other primary coil (hereinafter referred to as the secondary primary coil), the primary current is passed through the other primary coil. The direction of the magnetic flux generated by energizing the secondary 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 magnetic flux generated by the energization of the secondary primary coil act on the secondary coil. That is, since a magnetic flux change larger than the magnetic flux change due to the normal primary current cutoff 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 layered discharge type ignition device, a relatively large amount of discharge energy can be obtained from the spark plug, so that the ignitability of the fuel is improved, and thus the fuel consumption is also improved.

However, since the overlapping discharge type ignition device described in Patent Document 1 uses an active element in order to change the energization amount and energization time of the sub-primary coil, if the active element does not operate normally, the sub-primary coil is used. It is not possible to properly control the energization of the coil. For example, if the active element used to control the energization of the secondary primary coil cannot operate normally due to heat generation, appropriate overlapping discharge cannot be realized and sufficient discharge energy cannot be given to the secondary side, or conversely, due to overcurrent. There is a risk of accelerating the wear of the spark plug.

As described above, when the active element used for controlling the energization of the secondary primary coil cannot operate normally due to heat generation, it is desirable to ensure safety without continuing the unstable superimposition operation as it is, but the ignition described in Patent Document 1 is described. The device is not provided with such a function.

Therefore, an object of the present invention is to provide an ignition device for an internal combustion engine that can stably perform superimposed discharge using a secondary primary coil.

In order to solve the above problems, the ignition device for an internal combustion engine applies 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 an ignition plug, the ignition coil has an increase in the amount of magnetic flux in the forward direction due to energization of a main primary current performed when the ignition signal is on, and the ignition signal is turned off. By interrupting the main primary current, the amount of magnetic flux in the forward direction is reduced, and by passing a superposed current through the discharge period after the main primary coil is de-energized, the reverse of the forward direction is achieved. It has a secondary primary coil that generates magnetic flux in the breaking direction, and a secondary coil whose one end side is connected to the ignition plug and the magnetic flux changes of the main primary coil and the secondary primary coil act to give discharge energy. , It is composed of an active element that increases or decreases the amount of electricity applied to the sub-primary coil according to the input active signal, energizes and shuts off the sub-primary coil, and changes the amount of electricity applied to the sub-primary coil. Then, the sub-primary coil energizing means for changing the amount of magnetic flux in the breaking direction, and the superimposition control means for actively operating by sending the active signal to the sub-primary coil energizing means after the energization of the main primary coil is cut off. The sub-primary coil energizing means is based on an abnormal state detecting means for detecting an abnormal state in which the sub-primary coil energizing means may not operate normally due to heat generation and the abnormal state detecting means for detecting the abnormal state. It is characterized in that it is provided with a heat generation suppressing means for suppressing the heat generation of the above.

Further, in the above configuration, the abnormal state detecting means determines the abnormal state when the collector-emitter voltage Vce of the active element constituting the sub-primary coil energizing means reaches a predetermined regulation threshold value. You may.

Further, in the above configuration, the heat generation suppressing means may suppress heat generation of the secondary primary coil energizing means by shutting off the energization of the sub primary coil.

Further, in the above configuration, the heat generation suppressing means may stop the active signal output from the superposition control means and cut off the energization of the sub-primary coil by the sub-primary coil energizing means.

Further, in the above configuration, the heat generation suppressing means changes the active signal output from the superposition control means and operates the active element constituting the sub-primary coil energizing means in the saturation region, thereby causing the sub-primary coil. The heat generation of the energizing means may be suppressed.

Further, in the above configuration, the superimposition control means includes a capacitor that starts charging after the energization of the main primary coil is cut off, and the active signal generated by using the charge accumulation state of the capacitor as an index after the start of charging is used. By outputting to the sub-primary coil energizing means, the increase of the superposed current with the passage of time is controlled. In the heat generation suppressing means, when the abnormal state detecting means detects the abnormal state, the superimposing control means By reducing the amount of charge accumulated in the capacitor to be provided and changing the active signal, the heat generation of the sub-primary coil energizing means may be suppressed.

According to the ignition device for an internal combustion engine having the above configuration, when the abnormal state detecting means detects an abnormal state in which the secondary primary coil energizing means may not operate normally due to heat generation, the heat generation suppressing means operates to energize the secondary primary coil. Since the heat generation of the means is suppressed, the superimposed discharge using the secondary primary coil can be stably performed.

It is a schematic block diagram of the ignition device for an internal combustion engine which concerns on this embodiment. It is a schematic block diagram which shows the 1st structural example of the superimposition function part. It is a waveform diagram which showed the waveform in the main part of the ignition device for an internal combustion engine provided with the superimposing function part of the 1st configuration example. It is a schematic block diagram which shows the 2nd structural example of the superimposing function part. It is a waveform diagram which showed the waveform in the main part of the ignition device for an internal combustion engine provided with the superimposing function part of the 2nd configuration example. It is a schematic block diagram which shows the 3rd structural example of the superimposition function part. It is a waveform diagram which showed the waveform in the main part of the ignition device for an internal combustion engine provided with the superimposing function part of the 3rd configuration example.

Next, the ignition device 1 for an internal combustion engine according to the present embodiment will be described in detail based on the attached drawings.

The ignition device 1 for an internal combustion engine shown in FIG. 1 includes one spark plug 2 provided for each cylinder of the internal combustion engine, and an ignition coil unit 10 provided with a function of generating discharge sparks in the ignition plug 2 in an integrated manner. .. Further, the function as an ignition control means for outputting an ignition signal Si or the like indicating the operation timing of the ignition coil unit 10 at an appropriate timing is an internal combustion engine drive control device 3 (for example, an ECU installed as standard in a vehicle). Is responsible. A DC power source 4 such as a vehicle battery is used as the power supply to the ignition coil unit 10. When the internal combustion engine has multiple cylinders, the internal combustion engine drive control device 3 may collectively perform ignition control for the ignition coil unit 10 for each cylinder, or ignition control means corresponding to each cylinder are individually provided. You may do so.

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

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

One end of the main primary coil 111a is connected to the DC power supply 4 via the connector 122, and a power supply voltage VB + (for example, 14V) is applied. The other end of the main primary coil 111a is connected to a collector of an ignition switch 13 using an IGBT (Insulated Gate Bipolar Transistor). The emitter of the ignition switch 13 is connected to the grounding point GND via the connector 122. One end of the secondary coil 112 is connected to the spark plug 2 via the high voltage terminal 121, and the other end is connected to the grounding point GND via the connector 122. The line from the secondary coil 112 to the grounding point connection terminal of the connector 122 has a rectifying element (for example, a cathode on the grounding side) that is in the forward direction from the secondary coil 112 toward the grounding point GND. A diode (a diode having an anode connected to each) is provided on the coil 112 side to regulate the flow path direction of the secondary current I2.

The ignition signal Si output from the internal combustion engine drive control device 3 at an appropriate timing of the discharge cycle is supplied to the ignition coil unit 10 via the connector 122 and input to the gate of the ignition switch 13. 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 non-feeding side of the main primary coil 111a is turned on. The end is connected to the grounding point GND. As a result, the main primary coil current (hereinafter referred to as the primary current I1a) from the feeding side to the ground side begins to flow in the main primary coil 111a, and the flow rate of the primary current I1a increases to the flow rate of the primary current I1a. The amount of magnetic flux of the energizing magnetic flux generated accordingly is stored as the energy of the magnetic field. On the secondary side of the ignition coil 11, electrical energy is stored by a minute capacitor component such as the secondary coil 112 and the connection wiring.

After the energy is stored as described above, when the energization of the main primary coil 111a is cut off at a predetermined ignition timing (for example, when the signal level of the ignition signal Si changes from H to L), a high-voltage electromotive force is generated. Is generated in the secondary coil 112 to generate a spark discharge between the discharge gaps of the spark plug 2, the secondary current I2 flows in the forward direction of the rectifying element 14, and the air-fuel mixture in the cylinder combustion chamber is ignited.

On the other hand, similarly to the main primary coil 111a, the secondary primary coil 111b that causes a magnetic field to act on the secondary coil 112 via the center core 113 has one end connected to the DC power supply 4 via the connector 122, and the power supply voltage VB +. (For example, 14V) is applied. The main primary coil 111a and the secondary primary coil 111b may not share the power supply but may use different power supplies. The secondary primary coil 111b generates magnetic flux in a direction opposite to the direction of the magnetic flux generated when the main primary coil 111a is energized (hereinafter referred to as the forward direction) (hereinafter referred to as the breaking direction). That is, the forward magnetic flux is sharply reduced by cutting off the energization of the main primary coil 111a, and if the secondary primary coil 111b generates the magnetic flux in the breaking direction, the amount of change in the magnetic flux acting on the secondary coil 112 is increased. It is possible to increase the discharge energy given to the secondary side.

The superimposition function unit 15 includes a function of controlling energization of the sub-primary coil 111b and the sub-primary coil 111b. The superimposition control unit 15 includes, for example, a superimposition switch 151 as a secondary primary coil energizing means using an IGBT, a superimposition control means 152, a superimposition signal forming means 153, an abnormal state detecting means 154, and a heat generation suppressing means 155. Only when stable ignition control cannot be performed with only the main primary coil 111a, such as when high EGR combustion is required, the superimposition control unit 15 is used to perform the superimposition operation, and if there is no particular need for the superimposition operation, the superimposition control unit 15 Does not need to work. The internal combustion engine drive control device 3 determines whether or not the superimposition operation is necessary, and when the superimposition operation is necessary, the superimposition operation is executed by outputting the superimposition signal Sp from the internal combustion engine drive control device 3 to the ignition coil unit 10. Will be done.

The other end (non-feeding side end) of the secondary primary coil 111b is connected to the collector of the superimposition switch 151 composed of the IGBT. The emitter of the superimposition switch 151 is connected to the grounding point GND via the connector 122. The superimposition switch 151 is an active element that increases or decreases the current between the collector and the emitter according to the active signal input to the gate, and goes to the sub-primary coil 111b according to the active signal output from the superimposition control means 152 described later. Controls the energization / shutoff and increase / decrease of the amount of energization.

The superimposition signal Sp, which is a reference for causing the superimposition switch 151 to perform active operation, is a signal output after the ignition timing by the ignition signal Si (after the primary current is cut off of the main primary coil 111a), and is output from the internal combustion engine drive control device 3. It is supplied to the superimposing function unit 15 in the ignition coil 11. The superimposition signal Sp is formed into an appropriate signal by the superimposition signal forming means 153 and supplied to the superimposition control means 152, and based on this, the superimposition control means 152 generates an active signal and outputs it to the superimposition switch 151. If the amount of electricity supplied to the secondary primary coil 111b is gradually increased with the passage of time from the start of the superimposition operation, it is possible to extend the high current period on the secondary side while suppressing power consumption, which is efficient. Stable ignition capacity can be realized. The method of generating an active signal in the superimposition control means 152 is not particularly limited, but as will be described later, if the charge accumulation state of the capacitor is used as an index, a comparison using discrete components having high heat resistance and noise resistance is used. An active signal generation function can be realized with a simple structure.

As described above, if an appropriate active signal is generated by the superimposition control means 152 and input to the gate of the superimposition switch 151, appropriate superimposition control is realized by performing appropriate energization control to the sub-primary coil 111b. it can. However, if the superimposition switch 151, which is an active element, cannot operate normally due to heat generation, there is a possibility that appropriate superimposition control based on the active signal generated by the superimposition control means 152 may not be realized. Therefore, the superimposition function unit 15 is provided with an abnormal state detecting means 154 for detecting an abnormal state of the superimposition switch 151 and a heat generation suppressing means 155 for suppressing heat generation of the superimposition switch 151.

The abnormal state detected by the abnormal state detecting means 154 is a state in which normal operation cannot be performed due to temperature rise due to heat generation of the element itself, but there is a high possibility that normal operation will be restored by temperature decrease. Therefore, the abnormal state may be detected by the abnormal state detecting means 154 by detecting the element temperature of the superimposition switch 151 and determining the abnormal state when the detected temperature reaches a predetermined regulated temperature. However, if a highly reliable temperature sensor with withstand voltage characteristics, noise resistance characteristics, etc. is used, the cost will increase. Therefore, if the collector-emitter voltage Vce of the superimposition switch 151 reaches a predetermined regulation threshold value and the abnormal state detecting means 154 is configured to detect the occurrence of the abnormal state, the abnormal state is inexpensive and highly reliable. The detection means 154 can be configured.

Based on the abnormal state detecting means 154 detecting the abnormal state, the heat generation suppressing means 155 performs an operation of suppressing the heat generation of the superimposition switch 151. As the heat generation suppression operation, a method of reducing the supply voltage from the DC power supply 4 to the secondary primary coil 111b may be used, but adding a step-down structure increases the cost, and heat generation from the step-down resistor or the like may become a problem. There is also sex. Therefore, the heat generation suppressing means 155 may stop the active signal from the superimposition control means 152 to the superimposition switch 151 to cut off the secondary primary current (hereinafter referred to as superimposition current I1b) and suppress the heat generation of the superimposition switch 151. .. Alternatively, the superimposition switch 151 may be operated in the saturation region by changing the active signal from the superimposition control means 152, and the collector-emitter voltage Vce may be brought close to 0 [V] to suppress the heat generation of the superimposition switch 151. ..

As described above, when an abnormality of the superimposition switch 151 is suspected, the superimposition switch 151 can be promoted to return to normal by the cooperation of the abnormal state detecting means 154 and the heat generation suppressing means 155. Therefore, the superimposition using the secondary primary coil 111b is used. The reliability of operation can be improved. Therefore, according to the ignition device 1 for an internal combustion engine including the superimposition function unit 15, the superimposition discharge using the secondary primary coil 111b can be stably performed.

What if the superimposition function unit 15 provided in the ignition coil unit 10 can control the superimposition current I1b to flow through the sub-primary coil 111b in response to the superimposition signal Sp which is the superimposition operation execution instruction from the internal combustion engine drive control device 3? It may be configured as. As an example, FIG. 2 shows a superimposing function unit 15A of the first configuration example.

For example, the superimposition signal forming means 153 operates by receiving the operating power supply Vcc, and outputs the superimposition instruction signal Sp'synchronized with the superimposition signal Sp to the superimposition control means 152a via the superimposition instruction signal line 153L1. The superimposition instruction signal Sp'is input to the non-inverting input (Vin (+)) of the comparator U1 via the non-inverting input signal line 152L1. A superimposition index capacitor C1 is connected between the non-inverting input signal line 152L1 and the ground line, and a voltage signal corresponding to the accumulated charge of the superimposition index capacitor C1 charged by the superimposition instruction signal Sp'is a voltage signal of the comparator U1. It is input to Vin (+).

On the other hand, the superimposition reference signal is input to the inverting input (Vin (-)) of the comparator U1 via the inverting input signal line 152L2. The comparator U1 outputs an output Vout corresponding to the difference between the non-inverting input and the inverting input as an active signal. The output active signal is input to the gate of the superimposition switch 151 via the active signal line 152L3. That is, since the superimposition switch 151 flows an on-current (collector current) corresponding to the active signal from the superimposition control means 152a, the superimposition current I1b flowing through the sub-primary coil 111b can be controlled. Since the capacitor C2 and the resistor R1 are provided in the line connecting the active signal line 152L3 and the inverting input signal line 152L2 to compensate for the phase, it is possible to suppress a sudden change in the output Vout of the comparator U1.

A capacitor C3 is provided on the inverting input signal line 152L2, and a signal having the same potential as the emitter of the superimposition switch 151 is input as a reference signal on the anti-ground side of the capacitor C3 via the reference signal introduction line 152L4. The reference signal introduction line 152L4 is connected between the emitter of the superimposition switch 151 and the resistor R3, and when the superimposition switch 151 is off, the reference signal becomes substantially the ground potential (for convenience, 0 [V]). That is, when the superimposition switch 151 is off and the superimposition operation is not performed, the capacitor C3 is not charged and the inverting input of the comparator U1 is 0 [V]. Further, if the superimposition signal Sp is off and the superimposition operation is not performed, the superimposition instruction signal Sp'is not output from the superimposition signal forming means 153 and the superimposition index capacitor C1 is not charged. It is 0 [V]. Therefore, when the superimposition signal Sp is off and the superimposition operation is not performed, the output Vout of the comparator U1 is maintained at 0 [V] and the superimposition switch 151 is not turned on. Not flowing.

When the superimposition operation is performed after the ignition timing (the timing at which the ignition signal Si changes from ON to OFF) that cuts off the primary current I1a flowing through the main primary coil 111a, the internal combustion engine drive control device 3 superimposes the signal Sp on the ignition coil unit 10. Turn on. As a result, the superimposition instruction signal Sp'is output from the superimposition signal forming means 153, the superimposition index capacitor C1 is charged, and the voltage signal corresponding to the charge charge is Vin (+) of the comparator U1 via the non-inverting input signal line 152L1. ) Is entered. Even after the start of the superimposition operation, the superimposition switch 151 is still off, so the input of Vin (-) of the comparator U1 is maintained at 0 [V], depending on the difference between Vin (+) and Vin (-). The active signal is input to the gate of the superimposition switch 151 via the active signal line 152L3.

When the accumulated charge of the superimposition index capacitor C1 increases due to the start of the superimposition operation, the signal potential of the active signal output from the comparator U1 rises, and when the gate input of the superimposition switch 151 reaches the on voltage, the superimposition switch 151 turns on. Become. When the superimposition switch 151 is off, the collector-emitter voltage Vce is a value close to the power supply voltage of the DC power supply 4, but when the superimposition switch 151 is turned on, the Vce decreases according to the collector current flowing. As a result, the signal potential of the reference signal introduction line 152L4 connected to the emitter side of the superimposition switch 151 rises from the resistor R3, the capacitor C3 is charged, and the inverting input signal is charged according to the charge charge of the capacitor C3. The signal potential of line 152L2 rises. Therefore, the input value of Vin (-) of the comparator U1 rises, the slope of the increase of the output Vout of the comparator U1 becomes gentle, and the signal level is sufficient to flow the superposed current I1b presumed to be suitable. You will be able to maintain an active signal.

When the specified superimposition time elapses after the superimposition operation as described above is started, the superimposition signal Sp is turned off, and the superimposition instruction signal Sp'from the superimposition signal forming means 153 is also turned off. The capacitor C3 is discharged, and Vin (+) and Vin (−) of the comparator U1 return to 0 [V]. Therefore, the active signal from the comparator U1 to the superimposition switch 151 is also turned off, and the superimposition current I1b does not flow through the secondary primary coil 111b.

The abnormal state detecting means 154a for detecting the abnormal state of the superimposing switch 151 controlled by the active signal from the superimposing control means 152a monitors the collector-emitter voltage Vce of the superimposing switch 151. The abnormality state detecting means 154a stores in advance an abnormality determination threshold value as a regulation threshold value for determining whether or not there is an abnormality. If the normal superimposition operation is performed, the Vce detection value of the superimposition switch 151 does not reach the abnormality determination threshold value, but an abnormality such as a load state change between the plug electrodes of the spark plug 2 or a voltage fluctuation of the DC power supply 4 If there is, the Vce detection value rises and reaches the abnormality determination threshold value. That is, the abnormal state detecting means 154a detects that the Vce detection value of the superimposition switch 151 reaches the abnormality determination threshold value as the occurrence of the abnormal state, and notifies the heat generation suppressing means 155a that the abnormal state has been detected.

The heat generation suppressing means 155a is connected to the superimposition instruction signal line 153L1 via the heat generation suppression signal line 155L1, and the superimposition instruction signal line 153L1 can be short-circuited to the ground line. When the superimposition instruction signal line 153L1 is short-circuited to the ground line, the signal potential of the non-inverting input signal line 152L1 drops to the ground potential even if the superimposition instruction signal Sp'is on, so that an active signal is output from the comparator U1. The superimposition switch 151 is turned off. That is, the heat generation suppressing means 155a notified by the abnormal state detecting means 154a that an abnormal state has occurred cuts off the active signal to the superimposition switch 151 by short-circuiting the heat generation suppression signal line 155L1 to the ground line, and superimposes the signal. It suppresses the heat generation of the switch 151 itself. The heat generation suppressing means 155a may short-circuit the active signal line 152L3 to the ground line to cut off the active signal.

An example of the superimposition operation by the ignition device 1 for an internal combustion engine including the superimposition function unit 15A configured as described above will be described with reference to FIG. In FIG. 3, the first ignition control shown on the left side shows the case where the heat generation of the superimposition switch 151 is not detected during the superimposition operation, and the second ignition control shown on the right side shows the case where the heat generation of the superimposition switch 151 is detected during the superimposition operation. Indicates the case.

The ignition signal Si is turned on and off to energize and shut off the main primary coil 111a, spark discharge occurs in the spark plug 2 to which a high voltage is applied, and the secondary current I2 flows through the secondary coil 112. Become. For example, the superimposition signal Sp is turned on at the same time as the ignition timing when the ignition signal Si is turned off, and the superimposition operation is started. The start timing of the superimposition operation may be after the ignition timing at which the spark plug 2 causes a spark discharge, and the superimposition operation may be started with a slight grace period from the ignition timing.

When the superimposition signal Sp is turned on, an active signal is input from the superimposition control means 152a to the gate of the superimposition switch 151, the superimposition switch 151 is turned on, and the superimposition current I1b starts to flow in the secondary primary coil 111b. When the superimposition operation is started, discharge energy is given to the secondary side from the secondary primary coil 111b through which the superimposition current I1b is passed, so that the reduced secondary current I2 increases and the spark discharge in the spark plug 2 Can be suitably sustained.

As in the first ignition control, if the Vce detection value input to the abnormal state detection means 154a decreases in a normal manner as the superimposition current I1b increases, the Vce detection value continues until the specified superimposition time elapses. Does not exceed the abnormality determination threshold. This abnormality determination threshold value is waveform information that can specify the regulation value for determination based on the elapsed time after the start of the superposition operation. While the superimposition switch 151 is operating due to the start of the superimposition operation, the point cloud data of the Vce regulation value or the continuous characteristic curve that changes with the passage of time from the start of the operation of the superimposition switch 151 is set as the abnormality determination threshold value. This is the basic waveform for determining an abnormality for the superimposition switch 151 during the superimposition operation. Then, when the Vce detection value at a certain time after the superimposition switch 151 starts operation is equal to or higher than the abnormality determination threshold value at that time, it can be determined that there is a high probability that the superimposition switch 151 is generating heat.

The timing at which the abnormal state detection means 154a starts comparing the abnormality determination threshold value with the Vce detection value may be the superimposition start timing T0 when the superimposition signal Sp is turned on, but in this configuration example, the superimposition switch 151 is used. The energization start timing T1 was set when the operation started and the Vce detection value began to decrease. In this way, it is possible to reduce the possibility that erroneous detection will occur due to the difference in the delay time from the on-timing of the superimposed signal Sp to the start of the superimposed current I1b. On the other hand, the abnormality determination threshold value from T2, which is the period during which the superimposition switch 151 is not operating, to T1 (or T0) of the next ignition cycle may not be set, but for example, the power supply voltage applied to the collector of the superimposition switch 151. Set to a regulated high voltage value that is appropriately higher than that. In this way, the abnormal state detecting means 154a can detect a dangerous state in which an abnormally high voltage is applied to the superimposing switch 151 even during the period when the superimposing operation is not performed. However, when the abnormal state detecting means 154a detects an abnormal state in which a dangerous high voltage is applied to the superimposition switch 151, an effective heat generating suppressing effect cannot be obtained even if the heat generation suppressing means 155a operates, so that the abnormality is detected. The history may be transmitted to the internal combustion engine drive control device 3 or the like.

Further, in consideration of the case where the superimposition control is performed based on the superimposition signal Sp of the superimposition control time longer than the standard superimposition control time (for example, the specified ON width) such as when high EGR combustion is required, the maximum length of the superimposition switch 151 is taken into consideration. It is desirable to set the basic waveform for abnormality determination according to the operating time. In this case, when the superimposition switch 151 is turned off in an operation time shorter than the maximum operation time (for example, the time from T1 to T2 in FIG. 3), the Vce detection value exceeds the abnormality determination threshold value, which is an abnormality. The abnormality determination condition is satisfied by the state detecting means 154a. Therefore, it is desirable that the abnormal state detecting means 154a does not determine the Vce rise at the end of the superimposition operation as an abnormal state so that the heat generation suppressing means 155a does not uselessly perform the heat dissipation suppressing operation after the superimposing operation is completed. .. Alternatively, by shutting off the operation power supply to the abnormal state detecting means 154a and the heat generation suppressing means 155a at the end timing of the superimposing operation, the abnormal state detecting means 154a and the heat generating suppressing means 155a are disabled until the next superimposing operation is started. You can leave it.

When the superimposition signal Sp is turned off after the specified superimposition time elapses without the Vce detection value reaching the abnormality determination threshold value, the active signal from the superimposition control means 152a is stopped, the superimposition switch 151 is turned off, and the sub The superimposed current I1b does not flow through the primary coil 111b. That is, the superimposition operation of applying the discharge energy from the secondary primary coil 111b to the secondary side is completed. When the superimposition operation is completed, the discharge energy given to the secondary side from the secondary primary coil 111b disappears, so that the secondary current I2 returns to the normal value and further decreases with the passage of time.

On the other hand, after the start of the superimposition operation, the Vce detection value input to the abnormal state detecting means 154a does not decrease in a normal manner as the superimposition current I1b increases, and the Vce detection value becomes abnormal before the specified superimposition time elapses. When the determination threshold value is reached, a heat generation suppression operation such as the second ignition control is performed.

When the load state between the electrodes of the spark plug 2 changes and the load becomes lighter (for example, the spark discharge that swells between the electrodes of the spark plug 2 is blown out, resulting in a spark discharge that connects the electrodes in a short path. (When it seems to have changed), the collector-emitter voltage Vce of the superimposition switch 151 rises. Further, when a vehicle battery is used as the DC power supply 4, the collector-emitter voltage Vce of the superimposition switch 151 rises when the voltage rises due to fluctuations in the battery voltage. When the collector-emitter voltage Vce rises due to such a factor, heat is generated by the internal resistance of the superimposition switch 151, and there is a risk that the superimposition switch 151 cannot operate normally.

Therefore, as in the second ignition control, if the Vce detection value input to the abnormal state detection means 154a does not decrease in a normal manner and starts to increase in the middle, the Vce detection value reaches the abnormality determination threshold value. Become. When the Vce detection value reaches the abnormality determination threshold value, the abnormal state detecting means 154a detects this as the occurrence of an abnormal state, and the heat generation suppressing means 155a short-circuits the heat generation suppressing signal line 155L1 to the ground line. This is the execution timing of the heat generation suppression operation, the active signal to the superposition switch 151 is cut off, and the superimposition switch 151 is turned off, so that the heat generation of the superimposition switch 151 itself is suppressed.

In the ignition cycle in which the second ignition control accompanied by the heat generation suppression operation as described above is performed, the necessary and sufficient discharge energy may not be given to the secondary side by the superimposition operation, but the superimposition switch 151 recovers by natural heat dissipation. Then, there is a high possibility that proper superposition operation can be performed in the next ignition cycle. That is, the internal combustion engine ignition device 1 that quickly determines the heat generation of the superposition switch 151 and performs the heat generation suppression operation can stably perform the superimposition discharge using the secondary primary coil 111b.

In the superimposition function unit 15A of the first configuration example described above, stopping the superimposition switch 151 is a heat generation suppression operation, but the heat generation suppression operation is not limited to this. FIG. 4 shows a superimposition function unit 15B of a second configuration example in which heat generation is suppressed by operating the superimposition switch 151 in a saturation region. The same configuration as that of the superimposition function unit 15A is designated by the same reference numerals and the description thereof will be omitted.

The heat generation suppression means 155b can raise the potential of the heat generation suppression signal line 155L1 connected to the superposition instruction signal line 153L1 to a heat generation suppression potential appropriately higher than the on voltage of the superposition instruction signal Sp'. When the potential of the heat generation suppression signal line 155L1 rises to the heat generation suppression potential by the heat generation suppression means 155b, the superimposition index capacitor C1 is charged to the heat generation suppression potential, the input potential of Vin (+) of the comparator U1 increases, and the input potential of Vin (+) of the comparator U1 increases. The potential of the active signal, which is the output Vout, also increases. When the potential of the active signal serving as the gate input becomes high and the gate-emitter voltage Vge of the superimposition switch 151 exceeds the threshold value, the collector current becomes saturated without further increase. When the superimposition switch 151 is operated in the saturation region, the collector-emitter voltage Vce is lowered and the resistance of the drift layer portion is significantly lowered, so that the heat generation of the superimposition switch 151 is suppressed.

Therefore, when the abnormal state detecting means 154a detects the abnormal state and the heat generation suppressing means 155b executes the heat generation suppressing operation for raising the superimposition instruction signal line 153L1 to the heat generation suppressing potential, the heat generation of the superimposing switch 151 can be suppressed. The heat generation suppression operation by the heat generation suppression means 155b needs to be completed in synchronization with the end timing of the superposition operation. Therefore, for example, the heat generation suppressing means 155b can detect the on / off of the superimposing signal Sp via the superimposing signal detection line 155L2, and the heat generation suppressing means 155b that detects the timing when the superimposing signal Sp is turned off voluntarily. The voltage application to the heat generation suppression signal line 155L1 may be terminated. In this way, the heat generation suppression operation can be ended in synchronization with the end timing of the superimposition operation.

An example of the superimposition operation by the ignition device 1 for an internal combustion engine including the superimposition function unit 15B configured as described above will be described with reference to FIG. Also in FIG. 5, the first ignition control shown on the left side shows the case where the heat generation of the superimposition switch 151 is not detected during the superimposition operation, and the second ignition control shown on the right side detects the heat generation of the superimposition switch 151 during the superimposition operation. Indicates the case where it is done.

In the first ignition control, the heat generation of the superimposition switch 151 is not detected (the Vce detection value does not reach the abnormality determination threshold value), so that the subprimary coil is the same as the superimposition operation by the superimposition function unit 15A of the first configuration example described above. A superposition operation is performed in which the discharge energy given to the secondary side is increased by energizing the 111b.

On the other hand, in the second ignition control, the Vce detection value input to the abnormal state detection means 154a does not decrease in a normal manner as the superimposition current I1b increases, and the Vce detection value becomes higher before the specified superimposition time elapses. The threshold value for abnormality determination is reached, and this is the execution timing of the heat generation suppression operation. That is, when the Vce detection value reaches the abnormality determination threshold value, the abnormal state detecting means 154a detects this as the occurrence of an abnormal state, and the heat generation suppressing means 155b transmits the potential of the superposed instruction signal line 153L1 via the heat generation suppressing signal line 155L1. To the heat generation suppression potential.

As a result, the signal potential of the output Vout of the comparator U1 increases, the superimposition switch 151 operates in the saturation region, and the Vce detection value becomes low (ideally, it becomes 0 [V]). When the superimposition switch 151 operates in the saturation region, the superimposition current I1b increases, and the secondary current I2 of the secondary coil 112 also increases. When the superimposition signal Sp is turned off after the specified superimposition time has elapsed, the heat generation suppression operation by the heat generation suppression means 155b is also terminated, the active signal from the superposition control means 152a is turned off, the superimposition switch 151 is also turned off, and the secondary primary The superimposed current I1b does not flow through the coil 111b. As a result, the discharge energy given to the secondary side from the secondary primary coil 111b disappears, so that the secondary current I2 returns to the normal value and decreases with the passage of time.

When the heat generation suppression operation by the heat generation suppression means 155b is performed, the superimposition switch 151 is operated in the saturation region and the superimposition current I1b is increased, so that the power consumption is increased. Therefore, the heat generation suppression operation by the heat generation suppression means 155b is not performed until the end timing of the superposition operation, and the heat generation suppression operation is terminated when the heat generation suppression holding time, which is highly probable that the superposition switch 151 has returned to the normal operation state, has elapsed. You may let it. If the end timing of the superimposition operation is reached before the heat generation suppression holding time elapses, the heat generation suppression operation may be ended in accordance with the end timing of the superimposition operation. If the superimposition operation continues even after the heat generation suppression holding time has elapsed, the potential of the superimposition instruction signal line 153L1 returns to the potential of the superimposition instruction signal Sp', so that the potential of the active signal decreases accordingly, and the sub The superimposed current I1b flowing through the primary coil 111b can be reduced, and power consumption can be suppressed.

In the superimposition function unit 15A of the first configuration example and the superimposition function unit 15B of the second configuration example described above, the superimposition current I1b is suddenly increased by stopping the superimposition switch 151 or operating the superimposition switch 151 in the saturated basin. The heat generation suppression operation was performed to increase or decrease the amount. The superimposing function unit 15C of the third configuration example shown in FIG. 6 suppresses heat generation by gradually increasing or decreasing the superimposing current I1b. In FIG. 6, the same configurations as those of the superimposing

function units

15A and 15B are designated by the same reference numerals, and the description thereof will be omitted.

As described above, the superimposition index capacitor C1 of the superimposition control means 152a is a capacitor that starts charging when the superimposition signal Sp is turned on after the energization of the main primary coil 111a is cut off. Then, the potential corresponding to the accumulated charge of the superimposition index capacitor C1 becomes the non-inverting input of the comparator U1, so that the active signal which is the output Vout of the comparator U1 has an ascending curve corresponding to the accumulated charge of the superimposition index capacitor C1. Draw. The superimposition switch 151 that operates by receiving an active signal that changes in such an ascending curve at the gate increases the collector current according to the ascending curve of the active signal. That is, by supplying the active signal generated by using the charge accumulation state of the superimposition index capacitor C1 as an index after the start of charging to the superimposition switch 151, it is possible to control the increase state of the superimposition current I1b with the passage of time. Therefore, if the increase / decrease in the accumulated charge amount of the superimposition index capacitor C1 can be controlled, the increase / decrease in the superimposition current I1b can be controlled.

Therefore, when the abnormal state detecting means 154c detects the abnormal state, the heat generation suppressing means 155c reduces the potential of the superimposing instruction signal line 153L1 via the heat generation suppressing signal line 155L1 to be sufficiently lower than the potential of the superimposing instruction signal Sp'. Performs heat generation suppression operation to lower the potential. As a result, the superimposition index capacitor C1 is discharged, and the active signal, which is the output Vout of the comparator U1, draws a downward curve according to the discharge of the superimposition index capacitor C1. The superimposition switch 151, which operates by receiving an active signal that changes in such a downward curve at the gate, causes the collector current to decrease according to the downward curve of the active signal. That is, since the superposed current I1b is reduced by the heat generation suppressing operation by the heat generation suppressing means 155c, the heat generation of the superimposing switch 151 can be suppressed.

In the heat generation suppression operation by the heat generation suppression means 155c, the potential of the superposition instruction signal line 153L1 may be lowered to the reduction potential at once in a very short time to shorten the discharge time of the superposition index capacitor C1, or the reduction potential may be gradually reduced. The discharge time of the superimposition index capacitor C1 may be lengthened by lowering to. Further, the heat generation suppression operation performed by the heat generation suppression means 155c may be continued until the end timing of the superposition operation when the superimposition signal Sp is turned off, or the heat generation suppression operation release condition which can be regarded as suppressing the heat generation of the superposition switch 151. May be terminated when is satisfied. In this configuration example, the heat generation suppression operation release condition is that a predetermined time width period (heat generation suppression operation execution period) that can be regarded as suppressing the heat generation of the superposition switch 151 has elapsed from the start of the superposition suppression operation. Thus, when the heat generation suppression operation execution period elapses from the start of the heat generation suppression operation, if the superposition operation is continuing (superimposition signal Sp is on), the potential of the superimposition instruction signal line 153L1 is again the superimposition instruction signal Sp ′. Since the potential returns to the above potential, charging of the superimposition index capacitor C1 can be started again. As a result, the potential of the active signal output from the superimposition control means 152a rises, and the collector current of the superimposition switch 151, which is highly likely to have returned to a state in which normal operation is possible, is increased, so that the discharge energy given to the secondary side can be increased. Can be raised again.

An example of the superimposition operation by the ignition device 1 for an internal combustion engine including the superimposition function unit 15C configured as described above will be described with reference to FIG. 7. Also in FIG. 7, the first ignition control shown on the left side shows the case where the heat generation of the superimposition switch 151 is not detected during the superimposition operation, and the second ignition control shown on the right side detects the heat generation of the superimposition switch 151 during the superimposition operation. Indicates the case where it is done.

In the first ignition control, the heat generation of the superimposition switch 151 is not detected (the Vce detection value does not reach the abnormality determination threshold value), so that it is the same as the superimposition operation by the

superimposition function units

15A and 15B of the first and second configuration examples described above. In addition, a superposition operation is performed to increase the discharge energy given to the secondary side by energizing the secondary primary coil 111b.

On the other hand, in the second ignition control, the Vce detection value input to the abnormal state detecting means 154c does not decrease in a normal manner as the superimposition current I1b increases, and the Vce detection value becomes higher before the specified superimposition time elapses. When the abnormality determination threshold value is reached, the heat generation suppression operation execution timing is reached. When the Vce detection value reaches the abnormality determination threshold value, the abnormal state detecting means 154c detects this as the occurrence of an abnormal state, and the heat generation suppressing means 155c reduces the potential of the superposed instruction signal line 153L1 via the heat generation suppressing signal line 155L1. Lower to potential.

As a result, the discharge of the superimposition index capacitor C1 starts, the accumulated charge of the superimposition index capacitor C1 decreases until the heat generation suppression execution period elapses, and the signal potential of the output Vout of the comparator U1 also decreases. The collector current also goes down. During the heat generation suppression execution period, the heat generation of the superimposition switch 151 is suppressed, but the discharge energy given to the secondary side also decreases as the superimposition current I1b decreases, and the secondary current I2 also decreases. However, if the heat generation suppression execution period elapses before the superimposition time elapses (before the superimposition signal Sp is turned off), the charge accumulation state of the superimposition indicating capacitor C1 is again after the heat generation suppression operation by the heat suppression means 155c is completed. The operation control of the superimposition switch 151 is executed using the above as an index.

When the heat generation suppressing operation by the heat generation suppressing means 155c is completed and the operation control of the superimposition switch 151 using the charge accumulation state of the superimposition indicating capacitor C1 as an index is restarted, it is desirable to monitor the abnormality of the superimposition switch 151 again. However, even if the abnormality monitoring with the abnormality determination basic waveform is continued from the energization timing T1 of the superimposed current I1b accompanying the start of the superposition operation to T2, the abnormality determination after the end of the heat generation suppression operation cannot be appropriately performed. Therefore, the abnormal state detecting means 154c temporarily resets the abnormal state detecting operation for the superimposition switch 151 at the timing T2'when the Vce detection value reaches the abnormality determination threshold value and detects the abnormal state. As a result, the abnormality determination threshold value that the abnormality state detecting means 154c compares with the Vce detection value returns to the same regulated high voltage value as when the superimposition switch 151 is not operating. After that, from the timing T1'when the heat generation suppressing means 155c, which has finished the heat generation suppressing operation, issues an abnormality detection restart instruction to the abnormal state detecting means 154c, the abnormal state detecting means 154c again sets the abnormality determination basic waveform as the abnormality determination threshold value. Start the judgment.

If the superposition switch 151 in which heat generation is suppressed returns to a state in which normal operation is possible after the heat generation suppression operation by the heat generation suppression means 155c is completed, the Vce detection value does not reach the abnormality determination threshold value, so that it is in an abnormal state. There is no abnormal state detection by the detection means 154c, and the superimposition operation is continued. If the superimposition switch 151 has not yet returned to the normal operation, the Vce detection value reaches the abnormality determination threshold value again, and the abnormality state detection means 154c detects the occurrence of the abnormality state, so that heat is generated again. There is a possibility that the heat generation suppressing operation by the suppressing means 155c is executed.

When the superimposition signal Sp is turned off after the specified superimposition time elapses, the active signal from the superimposition control means 152a is turned off, the superimposition switch 151 is also turned off, and the superimposition current I1b does not flow in the secondary primary coil 111b. As a result, the discharge energy given to the secondary side from the secondary primary coil 111b disappears, so that the secondary current I2 returns to the normal value and decreases with the passage of time.

Although the embodiment of the ignition device for an internal combustion engine according to the present invention has been described above based on the accompanying drawings, the present invention is not limited to this embodiment, and the configuration described in the claims is changed. It may be carried out by diverting known and existing equivalent technical means to the extent that it does not.

1 Ignition system for internal combustion engine 10 Ignition coil unit 11 Ignition coil 111a Main primary coil 111b Secondary primary coil 112 Secondary coil 13 Ignition switch 15 Superimposition function unit 151 Superimposition switch 152 Superimposition control means 154 Abnormal state detection means 155 Heat generation suppression means 2 Ignition Plug 3 Internal engine drive controller 4 DC power supply

Claims

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 ignition plug by controlling the energization of the ignition coil by turning on / off the ignition signal from the ignition control means.
In the ignition coil, the amount of forward magnetic flux increases due to the energization of the main primary current performed when the ignition signal is on, and the ignition signal is turned off to cut off the main primary current, whereby the forward magnetic flux is generated. The main primary coil whose amount is reduced, the sub-primary coil that generates magnetic flux in the breaking direction opposite to the forward direction by passing a superimposed current within the discharge period after the energization cutoff for the main primary coil, and the one end side are described above. It has a secondary coil that is connected to an ignition plug and that is given discharge energy by the action of changes in the magnetic flux of the main primary coil and the secondary primary coil.
It is composed of active elements that increase or decrease the amount of electricity applied to the sub-primary coil according to the input active signal, and by energizing and shutting off the sub-primary coil and changing the amount of electricity applied to the sub-primary coil. , The sub-primary coil energizing means that changes the amount of magnetic flux in the breaking direction,
A superimposition control means that sends the active signal to the sub-primary coil energizing means to actively operate after the energization of the main primary coil is cut off.
An abnormal state detecting means for detecting an abnormal state in which there is a risk that the secondary primary coil energizing means may not operate normally due to heat generation, and an abnormal state detecting means.
Based on the abnormality state detecting means detecting the abnormal state, the heat generation suppressing means for suppressing the heat generation of the secondary primary coil energizing means, and the heat generation suppressing means.
An ignition device for an internal combustion engine.
The abnormal state detecting means is characterized in that the abnormal state is determined when the collector-emitter voltage Vce of the active element constituting the sub-primary coil energizing means reaches a predetermined regulation threshold value. The ignition device for an internal combustion engine according to claim 1.
The internal combustion engine according to claim 1 or 2, wherein the heat generation suppressing means suppresses heat generation of the secondary primary coil energizing means by shutting off the energization of the sub primary coil. Ignition device.
The third aspect of the present invention is characterized in that the heat generation suppressing means stops the active signal output from the superimposition control means and cuts off the energization of the sub-primary coil by the sub-primary coil energizing means. Ignition system for internal combustion engines.
The heat generation suppressing means suppresses heat generation of the sub-primary coil energizing means by changing the active signal output from the superimposition control means and operating the active element constituting the sub-primary coil energizing means in a saturation region. The ignition device for an internal combustion engine according to claim 1 or 2, wherein the ignition device for an internal combustion engine is described.
The superimposition control means includes a capacitor that starts charging after the energization of the main primary coil is cut off, and sends the active signal generated using the charge accumulation state of the capacitor as an index to the sub-primary coil energization means after the start of charging. By outputting, it is assumed that the increase control of the superimposed current with the passage of time is performed.
When the abnormal state detecting means detects the abnormal state, the heat generation suppressing means reduces the charge accumulation amount of the capacitor included in the superimposition control means to change the active signal, thereby causing the secondary primary coil energizing means. The ignition device for an internal combustion engine according to claim 1 or 2, wherein the heat generation is suppressed.