WO2020179016A1

WO2020179016A1 - Ignition device for internal combustion engine

Info

Publication number: WO2020179016A1
Application number: PCT/JP2019/008867
Authority: WO
Inventors: 松野　正孝
Original assignee: 日立オートモティブシステムズ阪神株式会社
Priority date: 2019-03-06
Filing date: 2019-03-06
Publication date: 2020-09-10

Abstract

Provided is an ignition device which is for an internal combustion engine and with which it is possible to achieve adequate ignition properties without a reduction in energy efficiency, and to suppress wear in spark plugs. A discharge stopping means 15 is provided, which short-circuits both ends of a primary coil 111 in an ignition coil 11. Within the discharge cycle, when discharge stop conditions are met in which sufficient discharge energy is considered to have been applied from the primary coil 111 to a secondary coil 112, a drive control device 3 for an internal combustion engine outputs a discharge stop command signal Sd2 to the discharge stopping means 15, and the primary coil 111 is short circuited.

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 an ignition device for an internal combustion engine capable of suppressing wear of an ignition plug used in an internal combustion engine having poor ignitability.

As an internal combustion engine mounted on a vehicle, an ultra-lean burn engine and a high EGR engine are used to improve fuel efficiency. Since the ignitability of these engines is not so good, performance deterioration easily occurs due to wear of the spark plug. Further, the degree of wear of the spark plug has a great influence on the combustion control of the ignition device. Therefore, unless proper measures such as frequently replacing a deteriorated spark plug are taken, fuel consumption may be deteriorated. .. As one of the causes of deterioration of the spark plug, there is a problem that the spark discharge generated between the plug electrodes is blown off and re-discharged.

▽In spark discharge of spark plug, the maximum discharge energy immediately after the start of discharge causes dielectric breakdown between the gaps of the spark plug, sparks are formed in the gap, and then the discharge energy gradually decreases. The sparks generated in the course of this discharge are blown out by the flow of the air-fuel mixture after being expanded in the flow direction, and at the same time, a spark that connects the electrodes of the spark plug with a short path is formed. After that, re-discharge and blowout are repeated until the discharge energy by the ignition coil decreases to the extent that the spark discharge cannot be continued. The phenomenon of repeated re-strikes accelerates wear of the spark plug. Further, in the electrodes of the spark plug mounted in the cylinder, a flow of the air-fuel mixture (tumble flow) that is orthogonal to the discharge between the electrodes is generated, and the wear of the spark plug progresses in a biased direction of the air-fuel mixture. There is a possibility that the spark plug will deteriorate more quickly.

In order to prevent such deterioration of the spark plug, it is considered effective to suppress the occurrence of restrike. Therefore, in order to prevent the spark discharge from being blown off, the charge is stored in the energy input capacitor, and the charge is input from the energy input capacitor to the primary coil immediately after the ignition is started, and the continuous spark discharge is continued following the main ignition. An ignition device for an internal combustion engine that continues is proposed (for example, see Patent Document 1). According to the ignition device for an internal combustion engine described in Patent Document 1, by controlling so that the secondary current value does not decrease, it is possible to prevent the spark discharge generated between the electrodes of the spark plug from being extinguished, and ignition by restructuring. There is a possibility that abrasion around the plug electrode can be suppressed. In addition, in the internal combustion engine ignition device described in Patent Document 1, immediately after ignition is started, electric charge is injected from the energy injection capacitor to the primary coil to continue the spark discharge. It may be possible to improve the ignitability of the air-fuel mixture.

JP, 2015-200285, A

However, the ignition device for an internal combustion engine described in Patent Document 1 uses the energy input capacitor to increase the energy input to the primary side of the ignition coil and to maintain the continuous spark discharge. The required energy consumption increases. Therefore, there is concern that the energy efficiency of the ignition device for an internal combustion engine may be reduced. In addition, since the continuous spark discharge is maintained for each ignition, the total time of applying the high voltage between the electrodes of the spark plug becomes long, and there is a risk that the wear of the spark plug electrodes themselves is accelerated.

Therefore, an object of the present invention is to provide an ignition device for an internal combustion engine, which realizes necessary and sufficient ignitability without lowering energy efficiency and can prolong the life of a spark plug.

In order to solve the above problems, the first ignition device for an internal combustion engine is configured such that an energization magnetic flux is generated by energization and a primary coil in which the energization magnetic flux is reduced by cutting off the current, and one end side is connected to an ignition plug, An ignition coil having a secondary coil in which an energizing magnetic flux generated in the primary coil acts to generate discharge energy, a switch means for switching energization/interruption to the ignition coil, and a switching operation of the switch means are controlled. By doing so, the ignition control means for generating a spark discharge in the spark plug at a predetermined timing of the combustion cycle, and the ignition situation in the cylinder combustion chamber due to the spark discharge generated in the spark plug, it is possible to realize the necessary and sufficient ignitability. A discharge stop condition determination means for determining whether or not a discharge stop condition that can be regarded is satisfied, and a discharge stop instruction for outputting a discharge stop instruction signal when the discharge stop condition determination means determines that the discharge stop condition is satisfied. It is characterized by comprising means and a discharge stop means for suppressing the discharge energy given from the primary coil to the secondary coil by receiving a discharge stop instruction signal from the discharge stop instruction means and stopping the discharge of the ignition plug. And.

Further, in the first ignition device for an internal combustion engine, the discharge stopping means includes a short-circuit path for short-circuiting both ends of the primary coil, a resistance component contained in the short-circuit path, and a normally open short-circuit path for opening and closing the short-circuit path. It is composed of an open / close switch, and by receiving the discharge stop instruction signal, the short-circuit path open / close switch is closed to short-circuit both ends of the primary coil, and the discharge energy given from the primary coil to the secondary coil is suppressed. It may be configured.

Further, in the first ignition device for an internal combustion engine, the secondary coil current detection means for detecting the secondary current flowing in the secondary coil and the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug are good. A discharge stop reference value storage means for storing a preset discharge stop reference value as a secondary coil current value estimated that further discharge is not required is provided, and the discharge stop condition determination means is the secondary coil. When the secondary current detection value detected by the current detection means is less than or equal to the discharge stop reference value stored in the discharge stop reference value storage means, it is determined that the discharge stop condition is satisfied, and the discharge stop instruction means is indicated. The configuration may be such that the discharge stop instruction signal is output.

Further, in the first ignition device for an internal combustion engine, the discharge stop reference value storage means stores a plurality of discharge stop reference values set corresponding to an operating state of the internal combustion engine, and the discharge stop condition is set. The determining means may be configured to acquire the discharge stop reference value according to the operating state of the internal combustion engine from the discharge stop reference value storage means and determine the discharge stop condition.

The second ignition device for an internal combustion engine includes a main primary coil in which the amount of magnetic flux in the forward direction increases due to energization of the main primary current, and the amount of magnetic flux in the forward direction decreases due to interruption of the main primary current, and the main primary coil. A secondary primary coil that generates a superimposed magnetic flux in a blocking direction opposite to the forward direction by causing a superimposed current to flow in a discharge period after the energization of the main primary coil and the sub primary coil. Ignition coil having a secondary coil to which discharge energy is applied by the change in magnetic flux, main switch means for switching on/off of the main primary coil, and switching on/off of the sub primary coil. By switching on/off of the sub switch means and the main switch means and controlling energization/interruption of the main primary coil, a spark discharge is generated in the spark plug at a predetermined timing of a combustion cycle, and the main primary coil is discharged. In the cylinder combustion chamber due to spark discharge generated in the spark plug, ignition control means for switching the auxiliary switch means from off to on after energization of the coil and turning on the auxiliary primary coil to cause a superimposed current to flow in the auxiliary primary coil. Discharge stop condition determining means for determining whether or not the ignition condition satisfies the discharge stop condition that can be considered to have achieved necessary and sufficient ignitability, and the discharge stop condition determining means determines whether the discharge stop condition is satisfied. At this time, the discharge stop instruction signal for outputting the discharge stop instruction signal and the discharge stop instruction signal from the discharge stop instruction means are used to suppress the discharge energy given from the main primary coil to the secondary coil, thereby to It is characterized by comprising a discharge stopping means for stopping the discharge.

In the second ignition device for an internal combustion engine, the discharge stopping means includes a short-circuit path that short-circuits both ends of the main primary coil, a resistance component included in the short-circuit path, and a normally-open short circuit that opens and closes the short-circuit path. It may be configured with a road opening/closing switch.

Further, in the second ignition device for an internal combustion engine, the ignition control means, when receiving a discharge stop instruction signal from the discharge stop instruction means, turns off the sub switch means to turn on the superimposed current to the sub primary coil. May be cut off to eliminate the superimposed magnetic flux.

Further, in the second internal combustion engine ignition device, the secondary coil current detecting means for detecting the secondary current flowing through the secondary coil and the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the ignition plug are good. A discharge stop reference value storage means for storing a preset discharge stop reference value as a secondary coil current value estimated that further discharge is not required is provided, and the discharge stop condition determination means is the secondary coil. When the secondary current detection value detected by the current detection means becomes equal to or less than the discharge stop reference value stored in the discharge stop reference value storage means, it may be determined that the discharge stop condition is satisfied.

In the second ignition device for an internal combustion engine, the discharge stop reference value storage means stores a plurality of discharge stop reference values set corresponding to the operating state of the internal combustion engine, and the discharge stop condition is stored. The determination means may acquire the discharge stop reference value according to the operating state of the internal combustion engine from the discharge stop reference value storage means to determine the discharge stop condition.

Further, in the second ignition device for an internal combustion engine, the ignition control means switches off the sub switch means when a predetermined superposition time has elapsed from the start of supplying the superposition current to the sub primary coil, and the sub primary means is turned off. The superimposed current on the coil is cut off to eliminate the superimposed magnetic flux, and the discharge stop condition determining means determines that the discharge stop condition is satisfied when the ignition control means stops supplying the superimposed current to the secondary primary coil. The discharge stop instruction means may output a discharge stop instruction signal to the discharge stop means when the discharge stop condition determination means determines that the discharge stop instruction condition is satisfied.

Further, in the ignition device for the second internal combustion engine, the ignition control means switches the sub-switch means to off when a predetermined superposition time elapses from the start of supplying the superimposition current to the sub-primary coil, and the sub-primary The superposed current is cut off to the coil to eliminate the superposed magnetic flux, and the discharge stop condition determination means has passed the preset grace time after the ignition control means stops the superposed current supply to the sub-primary coil. The timing is determined to satisfy the discharge stop condition, and the discharge stop instruction means outputs a discharge stop instruction signal to the discharge stop instruction means when the discharge stop condition determination means determines that the discharge stop instruction condition is satisfied. You can

According to the internal combustion engine ignition device having the above-described configuration, when the ignition state in the cylinder combustion chamber due to the spark discharge generated in the spark plug can be considered to have obtained the necessary and sufficient ignitability, the discharge stop instruction means causes the discharge stop means. It does not interfere with good combustion conditions. Then, when the discharge stop condition is satisfied, the spark discharge is forcibly stopped to prevent restructuring that occurs in the spark plug, so that wear of the periphery of the spark plug electrode due to restrike can be suppressed and the life of the spark plug can be extended. It will be possible.

It is a schematic block diagram of the ignition device for an internal combustion engine which concerns on 1st Embodiment. 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 ignition device for an internal combustion engine 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 ignition device for an internal combustion engine which concerns on 3rd Embodiment. FIG. 7A is a waveform diagram showing first discharge stop control performed by the internal combustion engine ignition device according to the third embodiment. (B) is a waveform diagram showing a second discharge stop control performed by the internal combustion engine ignition device according to the third embodiment.

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

An internal combustion engine ignition device 1 shown in FIG. 1 includes an ignition coil unit 10 for generating a spark discharge in one spark plug 2 provided for each cylinder of an internal combustion engine, and an ignition signal Si for instructing an operation timing of the ignition coil unit 10. And an internal combustion engine drive control device 3 which outputs a discharge stop instruction signal Sd2 for forcibly stopping the discharge and the like, a DC power source 4 such as a vehicle battery, and the like.

Further, in the ignition device 1 for an internal combustion engine shown in the present embodiment, various functions for controlling the ignition coil unit 10 are included in the internal combustion engine drive control device 3 that comprehensively controls the internal combustion engine of an automobile. However, it is not limited to this integral structure. For example, a discharge stop control device is provided separately from an ECU (corresponding to the internal combustion engine drive control device 3) that has a function of generating the ignition signal Si and outputting it at an appropriate timing as standard, and discharges the function related to the discharge stop control. It may be provided in the stop control device.

The ignition coil unit 10 is a unit having an integral structure in which the ignition coil 11, the control board, etc. 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 spark plug 2 is connected via the high-voltage terminal 121, and the internal combustion engine drive control device 3 and the DC power source 4 are connected via the connector 122. Connecting.

The ignition coil 11 efficiently causes the magnetic flux generated in the primary coil 111 to act on the secondary coil 112. For example, the structure is such that the primary coil 111 is arranged so as to surround the center core 113 formed of a highly permeable magnetic material, and the secondary coil 112 is arranged outside the primary coil 111.

The one end of the primary coil 111 is connected to the DC power supply 4 via the connector 122, and the power supply voltage VB+ (for example, 12V) is applied. The other end of the primary coil 111 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 internal combustion engine drive control device 3 via the connector 122. The line from the secondary coil 112 to the connector 122 has a rectifying element D1 (for example, a cathode on the ground side and an anode on the connector 122 side) in the forward direction from the secondary coil 112 toward the connector 122. A connected diode) is provided to regulate the flow path direction of the secondary current I2.

The ignition signal Si output from the ignition control means 31 of the internal combustion engine drive control device 3 is input to the gate of the ignition switch 13 via the connector 122 at an appropriate timing of the discharge cycle. 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-power supply side end of the primary coil 111. The part is connected to the ground point GND. As a result, the primary current I1 from the power supply side to the ground side starts to flow in the primary coil 111, the flow rate of the primary current I1 increases, and the amount of magnetic flux of the energizing magnetic flux generated according to the flow rate of the primary current I1 increases. It is stored 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 energization of the primary coil 111 is interrupted at a predetermined ignition timing, a high-voltage electromotive force is generated in the secondary coil 112 and a spark discharge is generated in the discharge gap of the spark plug 2. Occurs, and the air-fuel mixture in the cylinder combustion chamber is ignited. At this time, a counter electromotive force is generated in the primary coil 111 in an attempt to flow a current in the opposite direction to the normal primary current I1. 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 may fail or the ignition switch 13 may deteriorate faster. Therefore, a bypass line 14 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 14 toward the ignition coil 11 side). , Diodes having anodes respectively connected to the emitter side of the ignition switch 13 are provided.

Further, the ignition coil unit 10 is provided with a discharge stopping means 15 for stopping the discharge of the spark plug 2. The discharge stopping means 15 has a function of suppressing discharge energy applied from the primary coil 111 to the secondary coil 112 to forcibly stop the discharge of the spark plug 2, and a discharge stop instruction from the internal combustion engine drive control device 3. It operates by the signal Sd2. The discharge is stopped when it can be considered that the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 has achieved the necessary and sufficient ignitability. By forcibly stopping the discharge so that the discharge of the spark plug 2 does not continue more than necessary, it is possible to suppress wear of the spark plug 2 due to re-strike, and it is possible to prolong the life of the spark plug 2.

The discharge stopping means 15 includes, for example, a short-circuit path 15a that short-circuits both ends of the primary coil 111, a resistance component 15b included in the short-circuit path 15a, and a normally-open short-circuit opening/closing switch 15c that opens/closes the short-circuit path 15a. Constitute. The short circuit opening/closing switch 15c is not limited to the contact type switch, and a semiconductor switch element capable of high speed switching operation with low power consumption may be used.

The discharge energy applied from the primary coil 111 of the ignition coil 11 to the secondary coil 112 is generally considered to be divided into capacitive discharge energy that occurs for a short time immediately after the interruption of energization and induction discharge energy that continues for a relatively long time. The capacitive discharge energy is a very high electromotive force that is generated when the electric charge accumulated in the secondary coil 112 is discharged at a stroke while the primary coil 111 is energized. On the other hand, the induced discharge energy is an induced electromotive force that occurs when the energizing magnetic flux generated by energizing the primary coil 111 is sharply reduced by the interruption of energization, and the change in the magnetic flux acts on the secondary side. Therefore, if the short-circuit opening/closing switch 15c is closed during the inductive discharge to short-circuit both ends of the primary coil 111, a current in the direction of eliminating the energized magnetic flux flows in the primary coil 111, and a high voltage in the direction of stopping the discharge is generated. It is generated in the secondary coil 112. That is, if the discharge stopping means 15 is operated during the induced discharge, the discharge energy given from the primary coil 111 to the secondary coil 112 is suppressed, so that the discharge of the spark plug 2 can be stopped.

As described above, in the ignition device 1 for an internal combustion engine of the present embodiment, the discharge stopping means 15 provided in the ignition coil 10 is operated at an appropriate timing after the start of the discharge to forcibly stop the discharge of the ignition plug 2. Therefore, the wear of the ignition plug 2 can be suppressed. Of course, it is necessary to determine an appropriate discharge stop timing so that the good combustion of the internal combustion engine is not hindered by operating the discharge stop means 15. Therefore, various functions of the discharge stop control provided in the internal combustion engine drive control device 3 will be described.

The internal-combustion-engine drive control device 3 uses the secondary flowing in the secondary coil 112 as information for determining whether or not the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 has achieved a necessary and sufficient ignitability. The current I2 is used. For this reason, the internal combustion engine drive control device 3 is provided with a secondary coil current detection means 32 for detecting the secondary current I2. The secondary coil current detection means 32 can be realized by, for example, a configuration that detects a voltage drop due to a shunt resistance inserted in a secondary current line connected to the ground point GND. Since the voltage value corresponding to the secondary current I2 is detected by the secondary coil current detecting means 32, the voltage value may be used as it is as the secondary current detecting value for determination, or is predetermined. The secondary current value may be obtained by converting the voltage value into the current value using the above equation.

The secondary current detection value detected by the secondary coil current detecting means 32 is supplied to the discharge stop condition determining means 33, and the discharge stop condition determining means 33 determines the success or failure of the discharge stop condition. That is, the discharge stop condition determination means determines whether or not the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 satisfies the discharge stop condition that can be considered to realize the necessary and sufficient ignitability. It is. The discharge stop condition determined by using the secondary current detection value is that the secondary current I2 has dropped to a predetermined discharge stop reference value (secondary current detection value ≤ discharge stop reference value). Alternatively, it is assumed that the secondary current I2 has fallen below a predetermined discharge stop reference value (secondary current detection value<discharge stop reference value). In a normal ignition state, the secondary current I2 gradually decreases immediately after the start of discharge due to the change in the magnetic flux in which the energizing magnetic flux of the primary coil 111 disappears. Therefore, if the secondary current I2 drops to the secondary current value when it is assumed that sufficient discharge is performed to form a flame nucleus suitable for in-cylinder combustion of the internal combustion engine, then the spark plug 2 Even if the discharge is forcibly stopped, normal combustion in the cylinder combustion chamber is not hindered.

As described above, it is presumed that the discharge stop reference value, which is the reference for determining the discharge stop condition, is that the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 is good and no further discharge is required. It is a value preset as the secondary coil current value, and is stored in the discharge stop reference value storage means 34. The discharge stop reference value is supplied from the discharge stop reference value storage means 34 to the discharge stop condition determination means 33 and is used to determine the discharge stop condition. The discharge stop reference value is a value set so as to be directly compared with the above-mentioned secondary coil current detection value.

Note that the discharge stop condition may be determined based on only one preset discharge stop reference value regardless of the operating state of the internal combustion engine, but the optimum discharge according to the operating state during low speed operation, high speed operation, etc. By properly using the stop reference value, more appropriate discharge stop control becomes possible. In this case, a plurality of discharge stop reference values set corresponding to the operating state of the internal combustion engine are stored in the discharge stop reference value storage means 34, and the discharge stop condition determining means 33 corresponds to the current operating state. The discharge stop reference value to be used may be selected from the discharge stop reference value storage means 34.

In addition, since the combustion characteristics of the internal combustion engine may differ slightly from cylinder to cylinder, the optimum discharge stop reference value is set for each cylinder, and the discharge stop condition is determined by the discharge stop reference value that differs from cylinder to cylinder. It may be configured to discharge. Further, since the combustion characteristics of the internal combustion engine may change due to deterioration over time and the like, the internal combustion engine drive control device 3 is provided with a discharge stop reference value setting means and stored in the discharge stop reference value storage means 34. The value may be rewritten to an appropriate discharge stop reference value. The discharge stop condition determining means 33 may use the detection value of the vehicle speed sensor that is standardly installed in the vehicle as means for knowing the current driving state. Alternatively, the discharge stop condition determining means 33 may autonomously determine the operating state from the operation mode according to the control state performed by the internal combustion engine drive control device 3.

The discharge stop condition determination means 33 compares the secondary current detection value detected by the secondary coil current detection means 32 with the discharge stop reference value stored in the discharge stop reference value storage means 34, and, for example, the secondary When the current detection value becomes equal to or lower than the discharge stop reference value, it is determined that the discharge stop condition is satisfied. When the discharge stop condition is satisfied, the discharge stop condition determination means 33 outputs the discharge stop condition determination signal Sd1 to the discharge stop instruction means 35. The discharge stop instruction means 35 receiving the discharge stop condition determination signal Sd1 outputs the discharge stop instruction signal Sd2. The discharge stop instruction signal Sd2 is input to the short-circuit path open / close switch 15c of the discharge stop means 15 via the connector 122 of the ignition coil unit 10 to close the normally open short-circuit path open / close switch 15c. That is, when the discharge stop condition determining means 33 determines that the discharge stop condition is satisfied, the discharge energy given from the primary coil 111 to the secondary coil 112 is suppressed, and the discharge of the spark plug 2 is stopped.

The internal combustion engine drive control device 3 may be configured such that the discharge stop condition determining means 33 is always functioning and the discharge stop control is always performed, or when the discharge stop control is required in consideration of the operation mode and the like. As long as the discharge condition determination means 33 may be activated. If the discharge stop control is configured only when it is estimated that the recharge occurs frequently due to the discharge of the spark plug 2, the discharge is stopped early in the ignition cycle in which the restrike does not occur, resulting in an incomplete combustion state. Such a problem can be effectively avoided.

Next, the operation when the discharge stop control is not performed and the operation when the discharge stop control is performed will be described based on FIG. 2 showing the waveform of the main part of the internal combustion engine ignition device 1.

First, the ignition cycle without discharge stop control will be explained. When the ignition signal Si is turned on and the energization of the primary coil 111 is started, the primary current I1 starts to flow. After that, when the ignition signal Si is turned off and the energization of the primary coil 111 is cut off, discharge energy is given to the secondary coil 112, spark discharge occurs in the spark plug 2, and the secondary current I2 starts to flow. After that, the secondary current I2 gradually decreases, and the discharge of the spark plug 2 naturally stops. During this period, from the waveform of the secondary voltage V2, it is estimated that the secondary voltage rises (extends the discharge path) and falls (blows out) alternately, and the restructuring is repeated.

That is, when the discharge stop control is not performed, even if the secondary current I2 is reduced to the discharge stop reference value, the discharge stop condition determination means 33 does not operate, so that it is estimated that further discharge is not necessary. Even after the discharge, the discharge energy is continuously applied from the primary coil 111 to the secondary coil 112. Therefore, even after the spark plug 2 has obtained a sufficient discharge to form a flame nucleus suitable for good in-cylinder combustion, the spark plug 2 repeats the restoration, and the electrode of the spark plug 2 Peripheral wear may progress, shortening the life of the spark plug 2.

On the other hand, in the ignition cycle in which the discharge stop control is performed, a spark discharge is generated in the spark plug 2 and the secondary current I2 that starts flowing to the secondary side falls to the discharge stop reference value (or falls below the discharge stop reference value. ), the discharge stop condition is satisfied, and the discharge stop condition determination means 33 operates. That is, the discharge stop condition determination means 33 outputs the discharge stop condition determination signal Sd1 (for example, a short pulse signal having a predetermined time width) to the discharge stop instruction means 35. When the discharge stop instruction means 35 receives the discharge stop condition determination signal Sd1 from the discharge stop condition determination means 33 (for example, when the rising edge of the signal pulse is detected), the discharge stop instruction signal Sd2 is output to stop the discharge. The short circuit opening/closing switch 15c of the means 15 is closed.

That is, when the discharge stop control is performed, the discharge stop condition is satisfied when the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 is good and it is estimated that further discharge is not required. Therefore, both ends of the primary coil 111 are short-circuited via the short-circuit path 15a. When both ends of the primary coil 111 are short-circuited, a current in the direction of extinguishing the energized magnetic flux flows in the primary coil 111, and a high voltage in the direction of stopping the discharge is generated in the secondary coil 112. As a result, the discharge of the spark plug 2 is forcibly stopped, so that repetitive re-strikes are prevented in the spark plug 2, wear of the electrodes around the spark plug 2 is suppressed, and the life of the spark plug 2 is extended. It becomes possible.

It is desirable that the short-circuit time that can be arbitrarily set as the time width Ts of the discharge stop instruction signal Sd2 is a time necessary and sufficient for the primary current I1 flowing through the primary coil 111 to return to zero. Further, the discharge stop instruction signal Sd2 may be output for the time width of the discharge stop condition determination signal Sd1 output by the discharge stop condition determination means 33 (indicated by a broken line in the waveform of the discharge stop condition determination signal in FIG. 2). In this case, the discharge stop condition determination means 33 adjusts the output time of the discharge stop condition determination signal Sd1 to output the discharge stop instruction signal Sd2 having a time width Ts suitable for the driving mode of the vehicle. It will be possible.

In the ignition device 1 for an internal combustion engine of the above-described embodiment, the secondary coil current detection value is used as the discharge stop condition, but the present invention is not limited to this. For example, the discharge stop condition may be established by detecting the occurrence of restrike based on the detected value of the secondary voltage V2 based on the rise/fall of the secondary voltage. In this case, the secondary voltage V2, which becomes a very high voltage, may not be directly detected, but the occurrence of restoration may be detected from the voltage change of the primary coil 111 to which the voltage change of the secondary coil 112 is transferred.

Next, a schematic configuration of the internal combustion engine ignition device 1'according to the second embodiment will be described with reference to FIG. The internal combustion engine ignition device 1'is configured to control the operation of an ignition coil unit 10' including an ignition coil 11' by an internal combustion engine drive control device 3'. The same components as those of the ignition device 1 for an internal combustion engine according to the first embodiment described above are designated by the same reference numerals and description thereof will be omitted.

In the ignition coil 11', the primary side coil is divided into a main primary coil 111a and a sub primary coil 111b by an intermediate tap, and power is supplied from the DC power source 4 which is a common power source through the intermediate tap. Since the main primary coil 111a and the sub primary coil 111b have the same winding direction, the directions of the currents that flow during energization are opposite. The main primary coil 111a and the sub primary coil 111b both cause magnetic flux to act on the secondary coil 112. For example, the main primary coil 111a and the secondary primary coil 111b are arranged so as to surround the center core 113, and the secondary coil 112 is further arranged outside the main primary coil 111a.

The non-power supply end of the main primary coil 111a is connected to the ground point GND via the main ignition switch 13'. The main ignition switch 13' can be constituted by an IGBT, and functions as a main switch means for switching between energization and interruption of the main primary coil 111a based on the main primary coil ignition signal Sa from the ignition control means 31'.

The non-power supply end of the sub primary coil 111b is connected to the ground point GND via the sub ignition switch 16. This sub ignition switch 16 can also be configured by an IGBT, and functions as a sub switch means for switching between energization and interruption of the sub primary coil 111b based on the sub primary coil superposition signal Sb from the ignition control means 31'.

First, when the main ignition switch 13' is turned on and the primary current I1a flows through the main primary coil 111a, an energizing magnetic flux is generated. When the main ignition switch 13'is turned off and the primary current I1a is cut off, the energizing magnetic flux sharply decreases. If the direction of the energizing magnetic flux is the positive direction, it is apparent that the blocking magnetic flux in the opposite direction acts and the energizing magnetic flux disappears. This change in magnetic flux acts on the secondary coil 112, so that discharge energy that causes dielectric breakdown is generated in the discharge gap of the spark plug 2.

Further, when the auxiliary ignition switch 16 is turned on after the interruption timing when the energization to the main primary coil 111a is interrupted and the superimposed current I1b flows through the auxiliary primary coil 111b, a superimposed magnetic flux in the same direction as the interrupted magnetic flux is generated. That is, since the superposed magnetic flux from the sub-primary coil 111b acts, the amount of change in the energized magnetic flux can be increased, and the discharge energy generated in the secondary coil 112 can be superposedly increased.

The internal combustion engine drive control device 3'for controlling the operation of the ignition coil unit 10' including the ignition coil 11' configured as described above will be described. When the discharge stop condition determination means 33 determines that the discharge stop condition is satisfied after the superimposed current I1b is passed through the sub-primary coil 111b to perform the superimposed discharge control for increasing the discharge energy applied to the secondary side, the discharge stop instruction means is provided. The discharge stop condition determination signal Sd1 is output to 35'. Upon receiving the discharge stop condition determination signal Sd1, the discharge stop instruction means 35' outputs the discharge stop instruction signal Sd2a and the discharge stop instruction signal Sd2b.

The discharge stop instruction signal Sd2a is input to the short-circuit path open / close switch 15c of the discharge stop means 15 via the connector 122 of the ignition coil unit 10 to close the normally open short-circuit path open / close switch 15c. Further, the discharge stop instruction signal Sd2b is input to the ignition control means 31', and the ignition control means 31' receiving this signal stops the sub primary coil superposition signal Sb and switches the sub ignition switch 16 from ON to OFF. The superimposed current I1b is cut off. That is, when the discharge stop condition determining means 33 determines that the discharge stop condition is satisfied, the discharge energy applied to the secondary coil 112 from the main primary coil 111a and the sub primary coil 111b is suppressed, and the discharge of the ignition plug 2 is stopped. It

The operation when the discharge stop control is not performed and the operation when the discharge stop control is performed will be described based on FIG. 4 showing the waveform of the main part in the internal combustion engine ignition device 1′ according to the second embodiment described above. ..

First, the ignition cycle without discharge stop control will be explained. When the main primary coil ignition signal Sa is turned on and the power supply to the main primary coil 111a is started, the main primary current I1a starts to flow. After that, when the main primary coil ignition signal Sa 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 is generated in the ignition plug 2 and the secondary current I2 is generated. Begins to flow. Further, when the main primary coil ignition signal Sa is turned off, the sub primary coil ignition signal Sb is turned on almost at the same time, so that the superposed current I1b starts to flow in the sub primary coil 111b, and the superposed magnetic flux is generated to the secondary side. The applied discharge energy is increased in a superimposed manner.

Note that the end timing of the superimposition control that causes the superimposition current I1b to flow through the sub primary coil 111b can be set arbitrarily. For example, the superimposition control end condition is that the superimposition time determined according to the engine speed elapses, the subprimary coil superimposition signal Sb is stopped at the timing when the superimposition time elapses, and the subignition switch 16 is turned off for superimposition. The current I1b may be cut off. Alternatively, the detection of the secondary voltage or the secondary current that can know the ignition condition in the cylinder combustion chamber satisfies the superposition control termination condition that can be considered to have achieved the necessary and sufficient ignitability, thereby performing the superposition control. You may end it.

After the superimposition control is started, the secondary current I2 gradually decreases. Then, when the sub-primary current I1b is cut off at the end timing of the superposition control, the superposition amount by the sub-primary coil 111b disappears and the secondary current I2 sharply decreases. Even after that, although the induction discharge energy is supplied to the secondary side by the magnetic flux remaining in the main primary coil 111a, the secondary current I2 further decreases and the discharge of the spark plug 2 naturally stops. Even after the end timing of the superposition control, the secondary voltage rises (extends the discharge path) and decreases (blowns out) from the waveform of the secondary voltage V2, and it is presumed that restrike had occurred.

That is, when the discharge stop control is not performed, even if the secondary current I2 is reduced to the discharge stop reference value, the discharge stop condition determination means 33 does not operate, and therefore the main primary coil 111a to the secondary coil continue to operate thereafter. Discharge energy is applied to 112. Therefore, even after the spark plug 2 has obtained a sufficient discharge to form a flame nucleus suitable for good in-cylinder combustion, the spark plug 2 repeats the restoration, and the electrode of the spark plug 2 Peripheral wear may progress, shortening the life of the spark plug 2.

On the other hand, in the ignition cycle in which the discharge stop control is performed, the secondary primary current I1b is interrupted at the timing of ending the superimposition control, the superimposed current due to the secondary primary coil 111b disappears, and the secondary current I2 rapidly decreases. Drops to the discharge stop reference value. That is, the discharge stop condition is satisfied at the same time as the end timing of the superposition control, and the discharge stop condition determination means 33 operates. Specifically, the discharge stop condition determination means 33 outputs a discharge stop condition determination signal Sd1 (for example, a short pulse signal having a predetermined time width) to the discharge stop instruction means 35'. Then, when the discharge stop instruction means 35' receives the discharge stop condition determination signal Sd1 from the discharge stop condition determination means 33 (for example, when the rising edge of the signal pulse is detected), the discharge stop instruction signal Sd2a is output to discharge. The short circuit opening/closing switch 15c of the stopping means 15 is closed.

That is, when the discharge stop control is performed, the discharge stop condition is satisfied when the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 is good and it is estimated that further discharge is not required. Therefore, both ends of the main primary coil 111a are short-circuited via the short-circuit path 15a. When both ends of the main primary coil 111a are short-circuited, a current in the direction of extinguishing the energizing magnetic flux flows in the main primary coil 111a, and a high voltage in the direction of stopping the discharge is generated in the secondary coil 112. As a result, the discharge of the spark plug 2 is forcibly stopped, so that repetitive re-strikes are prevented in the spark plug 2, wear of the electrodes around the spark plug 2 is suppressed, and the life of the spark plug 2 is extended. It becomes possible.

The secondary current I2 may fall to the discharge stop reference value before the end timing of the superposition control using the sub primary coil 111b, and the discharge stop condition may be satisfied. Even in such a case, when the ignition control means 31' receives the discharge stop instruction signal Sd2b output from the discharge stop instruction means 35', the ignition control means 31' promptly stops the sub primary coil superposition signal Sb, The superimposed current I1b is cut off. That is, since the superposition control is also terminated at the timing when the discharge stop condition is satisfied, there is no problem that the superimposition current I1b continues to flow in the secondary primary coil 111b even after the discharge stop means 15 is operated. When the ignition control means 31', which has already stopped outputting the sub-primary coil superposition signal Sb, receives the discharge stop instruction signal Sd2b from the discharge stop instruction means 35', it need only be ignored. Further, information on whether or not the sub primary coil superposition signal Sb is output is input to the discharge stop instruction means 35', and when the discharge stop condition is satisfied, the sub primary coil superposition signal Sb is still output. The discharge stop instruction signal Sd2b may be output only in the case of

In the internal combustion engine ignition device 1'according to the second embodiment described above, whether or not the discharge stop condition is satisfied is determined separately from the end timing of the superposition control, and the discharge stop means 15 is activated. However, if the superimposition control ending condition is set so that the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug 2 can be regarded as a state in which the necessary and sufficient ignitability is realized, the superimposition control termination condition is set. It is not necessary to determine the end timing and the discharge stop timing separately, and simple and practical ignition control can be realized. Therefore, the schematic configuration of the internal combustion engine ignition device 1 ″ according to the third embodiment will be described with reference to FIG. 5. The internal combustion engine ignition device 1 ″ includes an ignition coil unit 10 ′ including an ignition coil 11 ′. The operation is controlled by the internal combustion engine drive control device 3″. The same components as those of the internal combustion

engine ignition devices

1 and 1′ of the first and second embodiments described above are denoted by the same reference numerals. Is omitted.

The ignition control means 31″ of the internal combustion engine drive control device 3″ integrally controls energization/interruption of the main ignition coil 111a and the auxiliary ignition coil 111b, and includes the function of the discharge stop condition determination means 33″. For example, the ignition control means 31″ determines the timing at which the superimposing current I1b that has started to flow to the sub-primary coil 111b by outputting the sub-primary coil ignition signal Sb is cut off (superimposition control ending timing), and the superimposing control ends. Whether the discharge stop condition is satisfied is determined based on the timing.

The superposition control termination condition used by the ignition control means 31″ may be set arbitrarily. For example, the secondary coil current detection value is input from the secondary coil current detection means 32 to the ignition control means 31″ (in FIG. 5). , Indicated by a broken line), and the superposition stop condition may be that the secondary coil current detection value becomes equal to or lower than a predetermined superposition stop reference value. However, in the present embodiment, in order to further simplify the superimposition control, the superimposition control ending condition is set such that the superimposition time Tp having a predetermined time width elapses from the start of the superposition control. That is, the internal combustion engine drive control device 3″ according to the present embodiment determines whether the discharge stop condition is satisfied based on the superposition control end timing with the passage of the superposition time Tp, and performs the discharge stop control for operating the discharge stop means 15. ..

FIG. 6A is a waveform diagram showing the first discharge stop control performed by the internal combustion engine drive control device 3″. In this first discharge stop control, the discharge stop condition determining means of the ignition control means 31″ is shown. 32″ determines that the superposition control end condition is satisfied. That is, the ignition control means 31″ outputs the discharge stop instruction signal Sd1 at the timing when the sub-primary coil superposition signal Sb is stopped. Output to 35. Upon receiving the discharge stop instruction signal Sd1, the discharge stop instruction means 35 outputs the discharge stop instruction signal Sd2 to the discharge stop means 15. Therefore, at the same time as the end of the superimposition control, both ends of the main primary coil 111a are short-circuited via the short-circuit path 15a, and a current in the direction of eliminating the energized magnetic flux flows into the main primary coil 111a, and the high voltage in the direction of stopping discharge. Is generated in the secondary coil 112. As a result, the discharge of the spark plug 2 is forcibly stopped, so that the repetitive re-strike is not wastefully repeated in the spark plug 2, wear of the electrodes around the spark plug 2 is suppressed, and the life of the spark plug 2 is extended. It becomes possible to plan.

FIG. 6B is a waveform diagram showing the second discharge stop control performed by the internal combustion engine drive controller 3″. In this second discharge stop control, the discharge stop condition determining means of the ignition control means 31″ is used. 32″ determines that the discharge stop condition is satisfied when the grace time Te of the predetermined time width elapses from the satisfaction of the superposition control termination condition. That is, the ignition control means 31″ stops the sub-primary coil superposition signal Sb. When the grace period Te has elapsed, the discharge stop instruction signal Sd1 is output to the discharge stop instruction means 35. Upon receiving the discharge stop instruction signal Sd1, the discharge stop instruction means 35 outputs the discharge stop instruction signal Sd2 to the discharge stop means 15. Therefore, when the grace time Te elapses from the end of the superposition control, both ends of the main primary coil 111a are short-circuited via the short-circuit path 15a, and a current flowing in the main primary coil 111a flows to the main primary coil 111a to stop the discharge. A high voltage in the opposite direction is generated in the secondary coil 112. As a result, the discharge of the spark plug 2 is forcibly stopped, so that the repetitive re-strike is not wastefully repeated in the spark plug 2, wear of the electrodes around the spark plug 2 is suppressed, and the life of the spark plug 2 is extended. It becomes possible to plan. The grace period Te secures a slight ignition continuation period after the end of the superposition control using the sub-primary coil 111b, and the discharge stop condition that allows fine adjustment of the balance between ignition stability and restrike suppression can be set. It will be possible.

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

1 Ignition system for internal combustion engine (first embodiment)
11 Ignition coil 111 Primary coil 112 Secondary coil 15 Discharge stop means 2 Spark plug 3 Internal engine drive control device 31 Ignition control means 32 Secondary coil current detection means 33 Discharge stop condition determination means 34 Discharge stop reference value storage means 35 Discharge stop Indicator means 4 DC power supply

Claims

A primary coil in which an energizing magnetic flux is generated by energization and the energizing magnetic flux is reduced by shutting off the current, and one end side is connected to a spark plug, and the energizing magnetic flux generated in the primary coil acts to generate discharge energy. An ignition coil having a secondary coil,
A switch means for switching the energization / interruption of the primary coil and
By controlling the switching operation of the switch means, ignition control means for generating a spark discharge in the spark plug at a predetermined timing of a combustion cycle,
Ignition status in the cylinder combustion chamber due to spark discharge generated in the spark plug, a discharge stop condition determining means for determining whether or not a discharge stop condition that can be regarded as having realized a necessary and sufficient ignitability is satisfied,
Discharge stop instruction means for outputting a discharge stop instruction signal when the discharge stop condition determination means determines that the discharge stop condition is satisfied,
By receiving a discharge stop instruction signal from the discharge stop instruction means, the discharge energy applied to the secondary coil from the primary coil is suppressed, the discharge stop means for stopping the discharge of the spark plug,
An ignition device for an internal combustion engine, which comprises.
The discharge stopping means comprises a short-circuit path that short-circuits both ends of the primary coil, a resistance component included in the short-circuit path, and a normally-open short-circuit path open/close switch that opens/closes the short-circuit path,
The discharge stopping means that receives the discharge stop instruction signal closes the short-circuit opening/closing switch to short-circuit both ends of the primary coil, thereby suppressing discharge energy applied from the primary coil to the secondary coil. The ignition device for an internal combustion engine according to claim 1.
A secondary coil current detecting means for detecting the secondary current flowing through the secondary coil, and
Discharge stop reference value storage that stores a discharge stop reference value preset as a secondary coil current value estimated that the ignition state in the cylinder combustion chamber due to the spark discharge generated in the spark plug is good and further discharge is not required. Means and
Is provided
The discharge stop condition determination means is a discharge stop condition when the secondary current detection value detected by the secondary coil current detection means is equal to or less than the discharge stop reference value stored in the discharge stop reference value storage means. 3. The ignition device for an internal combustion engine according to claim 1, wherein it is determined that the discharge stop instruction signal is output to the discharge stop instruction means.
The discharge stop reference value storage means stores a plurality of discharge stop reference values set corresponding to the operating state of the internal combustion engine,
4. The discharge stop condition determination means acquires the discharge stop reference value according to the operating state of the internal combustion engine from the discharge stop reference value storage means, and determines the discharge stop condition. An ignition device for an internal combustion engine according to item 1.
The amount of forward magnetic flux increases when the main primary current is energized, and the amount of forward magnetic flux decreases when the main primary current is cut off, and the main primary coil is superimposed within the discharge period after the main primary coil is cut off. A secondary primary coil that generates superimposed magnetic flux in the breaking direction opposite to the forward direction by passing an electric current and one end side are connected to the ignition plug, and the magnetic flux changes of the main primary coil and the secondary primary coil act to generate discharge energy. Given a secondary coil, with an ignition coil,
The main switch means for switching the energization / shutoff of the main primary coil and
A sub-switch means for switching the energization / interruption of the sub-primary coil and
By switching on / off of the main switch means and controlling the energization / interruption of the main primary coil, a spark discharge is generated in the spark plug at a predetermined timing of the combustion cycle, and after the energization of the main primary coil is cut off. An ignition control means for switching the auxiliary switch means from off to on, and causing a superimposed current to flow in the auxiliary primary coil to generate a superimposed magnetic flux;
Discharge stop condition determining means for determining whether or not the ignition condition in the cylinder combustion chamber due to the spark discharge generated in the spark plug satisfies the discharge stop condition that can be regarded as achieving the necessary and sufficient ignitability.
Discharge stop instruction means for outputting a discharge stop instruction signal when the discharge stop condition determination means determines that the discharge stop condition is satisfied,
By receiving a discharge stop instruction signal from the discharge stop instruction means, to suppress the discharge energy applied from the main primary coil to the secondary coil, the discharge stop means for stopping the discharge of the spark plug,
An ignition device for an internal combustion engine, which comprises.
The discharge stopping means is characterized by comprising a short-circuit path for short-circuiting both ends of the main primary coil, a resistance component contained in the short-circuit path, and a normally open short-circuit path open / close switch for opening and closing the short-circuit path. The ignition device for an internal combustion engine according to claim 5.
When the ignition control means receives the discharge stop instruction signal from the discharge stop instruction means, the auxiliary switch means is switched off to cut off the superimposed current on the auxiliary primary coil so that the superimposed magnetic flux disappears. The ignition device for an internal combustion engine according to claim 5 or 6, characterized in that.
A secondary coil current detecting means for detecting the secondary current flowing through the secondary coil, and
Discharge stop reference value storage that stores a discharge stop reference value preset as a secondary coil current value estimated that the ignition state in the cylinder combustion chamber due to the spark discharge generated in the spark plug is good and further discharge is not required. Means and
Is provided
The discharge stop condition determination means is a discharge stop condition when the secondary current detection value detected by the secondary coil current detection means is equal to or less than the discharge stop reference value stored in the discharge stop reference value storage means. The ignition device for an internal combustion engine according to any one of claims 5 to 7, wherein it is determined that the above condition is satisfied.
The discharge stop reference value storage means stores a plurality of discharge stop reference values set corresponding to the operating state of the internal combustion engine,
9. The discharge stop condition determination means acquires the discharge stop reference value according to the operating state of the internal combustion engine from the discharge stop reference value storage means, and determines the discharge stop condition. An ignition device for an internal combustion engine according to item 1.
The ignition control means, when a predetermined superposition time has elapsed from the start of supplying the superposition current to the sub-primary coil, turns off the sub-switch means to cut off the superposition current to the sub-primary coil to generate a superposition magnetic flux. Let it disappear
The discharge stop condition determining means determines that the timing at which the ignition control means stops the supply of the superimposed current to the sub primary coil is a discharge stop condition being satisfied,
7. The discharge stop instruction means outputs a discharge stop instruction signal to the discharge stop means when the discharge stop condition determination means determines that the discharge stop instruction condition is satisfied. The ignition device for an internal combustion engine according to claim 6.
The ignition control means switches off the sub-switch means when a predetermined superimposition time elapses from the start of supplying the superimposition current to the sub-primary coil, cuts off the superimposition current to the sub-primary coil, and generates the superimposition magnetic flux. Let it disappear
The discharge stop condition determination means, after the ignition control means stops the superimposed current supply to the sub-primary coil, determines that the timing when the preset grace time has elapsed is the discharge stop condition is satisfied,
5. The discharge stop instruction means is characterized in that, when the discharge stop condition determination means determines that the discharge stop instruction condition is satisfied, the discharge stop instruction means outputs a discharge stop instruction signal to the discharge stop instruction means. The ignition device for an internal combustion engine according to claim 6.