JP2019143507A - Ignition device for internal combustion engine - Google Patents

Abstract

To provide an ignition device for an internal combustion engine capable of keeping stable combustion by securing a stable high curent period.SOLUTION: An ignition coil 11 is composed of a main primary coil 111a in which energization magnetic flux increased in a normal direction is suddenly decreased by blocking electric current after starting energization, an auxiliary primary coil 111b generating superposed magnetic flux in a direction opposite to the energization magnetic flux by the energization, and a secondary coil 112 on which primary-side magnetic flux change acts so that discharge energy is generated. By instructing operations to an auxiliary primary coil energization permission switch 51 and an auxiliary primary coil energization switch 52 for switching energization/blockage to the auxiliary primary coil 111b, by auxiliary primary coil energization control means 30, a fixed auxiliary primary current as a target flows to the auxiliary primary coil 111b, the discharge energy applied to the secondary side is kept constant, and a high current period of a stable secondary current I2 is secured, so that the stable combustion of the internal combustion engine can be kept.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ignition device for an internal combustion engine mounted on a motor vehicle, and increases discharge energy generated on the secondary side of an ignition coil in a superimposed manner to obtain good discharge characteristics.

  Direct-injection engines and high-EGR engines are adopted as internal combustion engines mounted on vehicles to improve fuel efficiency. However, these engines are not very ignitable, so a high-energy ignition system is required. Become. In view of this, a phase discharge ignition device has been proposed in which the output of another ignition coil is additionally superimposed on the secondary output of the ignition coil generated by the classic current interruption principle (for example, Patent Document 1). See).

  According to the ignition device described in Patent Document 1, by interrupting the primary current of the main ignition coil, the high voltage of several kV generated on the secondary side thereof causes dielectric breakdown in the discharge gap of the spark plug, thereby igniting. After starting the discharge current from the secondary side of the coil, the primary current of the auxiliary ignition coil connected in parallel with the main ignition coil is cut off, and a DC voltage of several kV generated on the secondary side is additionally superimposed. By doing so, since a large discharge energy can be given to the spark plug for a relatively long time, the ignitability to the fuel is improved, and the fuel consumption is also improved.

JP 2012-140924 A

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

  Also, by boosting the power supply voltage outside or inside the ignition coil and applying a high voltage directly to the secondary side of the coil, the energization time to the primary coil can be increased without increasing the energization time of the secondary coil. A method of increasing discharge energy and maintaining stable combustion is also conceivable. However, such a method requires a booster circuit that boosts the power supply voltage to several kV, so that the withstand voltage of the circuit to be mounted and the connection tolerance at a high voltage are required, resulting in a considerable increase in cost. . In addition, the use of the booster circuit increases the power consumption for ignition, which causes a deterioration in fuel consumption.

  Therefore, the present invention has an object to provide an ignition device for an internal combustion engine that can secure a stable high current period, maintain stable combustion, and also can optimize power consumption for ignition to reduce deterioration of fuel consumption. And

  In order to solve the above problem, an ignition device for an internal combustion engine according to claim 1 includes a main primary coil in which a positive magnetic flux is increased by energization and a positive magnetic flux is reduced by interrupting the current, An ignition coil having a secondary primary coil that generates additional magnetic flux in the reverse direction, and a secondary coil that is connected to a spark plug at one end and generates magnetic discharge energy by the magnetic flux of the primary primary coil and the secondary primary coil. , Main switch means for switching energization / cutoff to the main primary coil of the ignition coil, sub switch means for switching energization / cutoff to the sub primary coil, and a sub switch for permitting energization of the ignition coil to the sub primary coil Primary coil energization permission switch means, secondary primary current detection means for detecting secondary primary current flowing in the secondary primary coil of the ignition coil, and primary switching means for controlling the primary switch means After energizing the coil, the main primary coil is de-energized to generate a high voltage on the secondary side of the coil, generating a spark at the spark plug at a predetermined timing of the combustion cycle, and energizing the main primary coil. Ignition control means for permitting the sub primary coil energization permission switch means to energize the sub primary coil for a predetermined superimposition time after the shut off timing of shutting off, and controlling the sub switch means to control energization to the sub primary coil; The ignition control means compares the preset sub-primary current target value with the sub-primary current detection value detected by the sub-primary current detection means, so that the sub-primary current is the sub-primary current target. It is characterized in that the energization / interruption of the sub-primary coil is controlled so as to be a value.

  According to a second aspect of the present invention, in the ignition device for an internal combustion engine according to the first aspect, the ignition control means adjusts the power supplied to the sub primary coil by performing PWM control on the sub switch means. The secondary primary current flowing through the primary coil is increased or decreased.

  According to the ignition device for an internal combustion engine according to the present invention, it is possible to control the secondary primary current flowing through the secondary primary coil to be the secondary primary current target value so that a constant secondary primary current can flow. It is possible to superimpose a certain amount of discharge energy necessary and sufficient for maintaining the secondary side to ensure a stable high current period of the secondary current. Furthermore, since excessive power consumption for ignition can be optimized by suppressing excessive sub-primary current, deterioration of fuel consumption can also be reduced.

1 is a schematic configuration diagram showing an embodiment of an internal combustion engine ignition device according to the present invention. It is the wave form diagram which showed typically each part waveform in normal discharge control and superposition discharge control by the ignition device for internal combustion engines of embodiment. It is a schematic block diagram of a sub primary coil electricity supply control means.

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

  FIG. 1 shows an ignition device 1 for an internal combustion engine according to an embodiment of the present invention, an ignition coil unit 10 that generates a discharge spark in one spark plug 2 provided for each cylinder of the internal combustion engine, and the ignition An internal combustion engine drive control device 3 having a function as an ignition control means for outputting a main primary coil ignition signal Sa or the like for instructing an operation timing of the coil unit 10 at an appropriate timing, a DC power source 4 such as a vehicle battery, a sub primary coil energization It comprises a permission switch 51, a sub primary coil energization switch 52, and the like.

  In the internal combustion engine ignition device 1 shown in the present embodiment, the ignition control means is included in the internal combustion engine drive control device 3 that comprehensively controls the internal combustion engine of the automobile, but is not limited thereto. It is not a thing. For example, the ignition signal generated by the ignition signal generation function of the normal internal combustion engine drive control device 3 is received, an appropriate control signal is generated, the ignition coil unit 10, the sub primary coil energization permission switch 51, An ignition control means for outputting a control signal to the sub primary coil energization switch 52 may be separately provided.

  The ignition coil unit 10 includes, for example, an ignition coil 11, a main switch 12, a bypass line 13 provided in parallel with the main switch 12, rectifying means 14 provided on the bypass line 13, and the like in a case 15 having a required shape and an integrated structure. It is a unit. A high voltage terminal 151 and a connector 152 are provided at appropriate positions of the case 15, and the ignition plug 2 is connected via the high voltage terminal 151, and a direct current such as the internal combustion engine drive control device 3 and the vehicle battery is connected via the connector 152. The power source 4, the sub primary coil energization permission switch 51, the sub primary coil energization switch 52, and the like are connected.

  The ignition coil 11 causes a magnetic flux generated in the main primary coil 111a (for example, 90 turns) and the sub primary coil 111b (for example, 60 turns) to act on the secondary coil 112 (for example, 9000 turns). The primary primary coil 111a and the secondary primary coil 111b are arranged so as to surround the core 113, and the secondary coil 112 is further arranged outside thereof. The main switch 12 is main switch means for energizing / cutting off the main primary coil 111a, and can be configured using, for example, an IGBT (Insulated Gate Bipolar Transistor). Thus, the ignition coil unit 10 has a unit structure in which the ignition coil and the igniter are sealed in the case 15.

  The first end 111a1, which is one end of the main primary coil 111a, is connected to the DC power supply 4 through the connector 152, and is applied with a power supply voltage VB + (for example, 12V). The second end 111a2 which is the other end of the main primary coil 111a is connected to the collector of the main switch 12, and the emitter of the main switch 12 is connected to the ground point GND through the connector 152. That is, when the main primary coil ignition signal Sa output from the internal combustion engine drive control device 3 is input to the gate of the main switch 12 (when the signal level of the main primary coil ignition signal Sa changes from L to H), the main switch 12 is turned on, the second end 111a2 of the main ignition coil 111a is connected to the ground point GND, and the main primary current I1a from the first end 111a1 to the second end 111a2 flows through the main primary coil 111a. Thereby, a forward energization magnetic flux is generated in the main primary coil 111a.

  The first end 111b1 that is one end of the sub primary coil 111b is connected to the sub primary coil energization switch 52 via the connector 152, and the second end 111b2 that is the other end of the sub primary coil 111b is connected via the connector 152. The sub primary coil energization permission switch 52 is connected. The on / off of the sub primary coil energization permission switch 51 and the sub primary coil energization switch 52 is controlled by the internal combustion engine drive control device 3, and the first end 111b1 side of the sub primary coil 111b is connected to the DC power source 4, and the second end The 111b2 side is connected to the ground point GND, and the superimposed current I1b from the first end 111b1 to the second end 111b2 flows through the sub-primary coil 111b.

  When the superimposed current I1b flows through the sub-primary coil 111b, a superimposed magnetic flux in the direction opposite to the energized magnetic flux is generated, and this superimposed magnetic flux is the direction of the magnetic field induced on the secondary side when the energization is cut off to the main primary coil 111a. Is the same. That is, when the superimposed current I1b is passed through the sub primary coil 111b after the energization interruption timing to the main primary coil 111a, the discharge energy generated in the secondary coil 112 can be increased in a superimposed manner. In order to reverse the directions of the energized magnetic flux and the superimposed magnetic flux, the winding directions of the main primary coil 111a and the sub primary coil 111b are reversed, or the feeding direction to the main primary coil 111a and the sub primary coil 111b. It is sufficient to reverse the feeding direction.

  As described above, when the superposed magnetic flux is generated by energizing the sub primary coil 111b, the back electromotive force acts on the main primary coil 111a when the energization to the sub primary coil 111b is cut off. A reverse voltage for applying a current opposite to the primary current is applied between the collector and the emitter of the main switch 12, and the main switch 12 breaks down or the deterioration of the main switch 12 is accelerated. There is a risk. Accordingly, a bypass line 13 is provided in parallel with the main switch 12, and a rectifying means 14 (for example, a cathode is provided on the collector side of the main switch 12) that is forward from the ground point side of the bypass line 13 toward the ignition coil 11 side. In addition, a diode having an anode connected to the emitter side of the main switch 12 is provided.

  A current detection resistor 61a having an appropriate resistance value is inserted in the secondary current path while the secondary coil 112 is connected to the ground point GND via the connector 152. The current detection resistor 61a The secondary side voltage detection line 61b for detecting a voltage change and the current detection resistor 61a constitute a secondary current detection means. The secondary current detection signal obtained from the secondary side voltage detection line 61b is supplied to the internal combustion engine drive control device 3, and the internal combustion engine drive control device 3 flows to the secondary coil 112 based on this secondary current detection signal. The next current can be known.

  The sub primary coil energization permission switch 51 and the sub primary coil energization switch 52 provided separately from the ignition coil unit 10 described above may be provided separately or as a unit structure housed in the same case. good. Further, if a semiconductor device having a high withstand voltage and noise resistance is used as the sub primary coil energization permission switch 51 and the sub primary coil energization switch 52, the semiconductor device may be provided in the case 10 of the ignition coil unit 10.

  The sub primary coil energization permission switch 51 can be composed of a power MOS-FET having high-speed switching characteristics, and the drain of the sub primary coil energization permission switch 51 is on the second end 111b2 side of the sub primary coil 111b, and the sub primary coil energization permission switch. The source of 51 is connected to the ground point GND side, and the sub primary coil energization permission signal Sb <b> 1 is input from the internal combustion engine drive control device 3 to the gate of the sub primary coil energization permission switch 51. Therefore, when the sub primary coil energization permission signal Sb1 is turned on (for example, the signal level is L to H), the sub primary coil energization permission switch 51 is turned on, and the second end 111b2 of the sub primary coil 111b is set to the ground point GND. Will be connected.

  A current detection resistor 62a having an appropriate resistance value is inserted in the sub primary current path between the source of the sub primary coil energization permission switch 51 and the ground point GND, and the voltage generated by the current detection resistor 62a. The sub primary voltage detection line 62b for detecting the change and the current detection resistor 62a constitute a sub primary current detection means. The sub primary current detection signal obtained from the sub primary voltage detection line 62b is supplied to the internal combustion engine drive control device 3, and based on this sub primary current detection signal, the internal combustion engine drive control device 3 passes through the sub primary coil 111b. You can know the current. Then, the sub primary coil energization control means 30 (detailed later) in the internal combustion engine drive control device 3 generates an appropriate sub primary coil energization signal Sb2 using the detected value of the sub primary current, and the sub primary coil. The superposed magnetic flux generated in 111b can be appropriately controlled.

  The sub primary coil energization switch 52 can also be constituted by a power MOS-FET, the drain of the sub primary coil energization switch 52 is on the DC power supply 4 side, and the source of the sub primary coil energization switch 52 is the first end 111b1 of the sub primary coil 111b. The sub primary coil energization signal Sb <b> 2 is input from the internal combustion engine drive control device 3 to the gate of the sub primary coil energization switch 52. Therefore, when the sub primary coil energization signal Sb2 is turned on (for example, the signal level is L to H), the sub primary coil energization switch 52 is turned on, and the power voltage from the DC power supply 4 is applied to the first end 111b1 of the sub primary coil 111b. VB + is applied. In addition, a boost power supply circuit 53 (indicated by a two-dot chain line in FIG. 1) is provided in the sub primary coil switch unit 5 so that the power supply voltage VB + from the DC power supply 4 can be boosted and supplied to the sub primary coil 111b. Also good. In this way, the voltage applied to the sub primary coil 111b can be increased to increase the superimposed current I1b flowing through the sub primary coil 111b, so that larger energy can be superimposed from the sub primary coil 111b to the secondary coil 112. It becomes possible.

  Therefore, in the internal combustion engine ignition device 1 according to the present embodiment, the sub primary coil energization control means 30 controls the switching operation of the sub primary coil energization permission switch 51 and the sub primary coil energization switch 52 to generate the superimposed magnetic flux. The timing to generate, the magnitude of the superimposed magnetic flux, and the timing to eliminate the superimposed magnetic flux are adjusted. In particular, the sub primary coil energization control means 30 controls the amount of power supplied to the sub primary coil 111b so that the detection value of the sub primary current detected by the sub primary current detection means becomes a predetermined sub primary current target value. Thus, a constant secondary primary current can flow.

  Thus, in the internal combustion engine ignition device 1 according to the present embodiment, a constant amount of discharge energy necessary and sufficient to maintain stable combustion is superimposed on the secondary side, and a stable high current period of the secondary current is obtained. It can be secured. Moreover, since the sub primary coil energization control means 30 controls the power supplied to the sub primary coil 111b to a necessary and sufficient constant amount, it is possible to suppress the excessive sub primary current from flowing and reduce the power consumption for ignition. Can be appropriate. Therefore, it is possible to reduce the deterioration of fuel consumption by performing the superposed discharge control using the sub primary coil 111b.

  In FIG. 2, an example of schematic structure of the sub primary coil electricity supply control means 30 is shown. In addition, the structure of the sub primary coil electricity supply control means 30 is not limited to this. The function of the sub primary coil energization control means 30 may be realized by hardware logic or by computer control by software.

  The sub primary coil energization control means 30 does not operate during the normal discharge control using only the main primary coil 111a, and operates only during the superposed discharge control using both the main primary coil 111a and the sub primary coil 111b. For example, only when superposed discharge control is performed, the primary primary coil ignition signal Sa (or an equivalent control instruction signal) is input to the secondary primary coil energization control means 30, so that the secondary primary coil energization control means 30 Operate.

  The main primary coil ignition signal Sa is input to the sub primary coil energization timing determination means 31 of the sub primary coil energization control means 30, and an appropriate timing at the same time as or after the energization cut-off timing to the main primary coil 111a is obtained. The sub-primary coil energization permission signal generation means 32 is notified of the coil energization permission signal output timing, and the sub-primary coil energization permission signal Sb1 generated by the sub-primary coil energization permission signal generation means 32 is supplied to the sub-primary coil energization permission switch 51. Then, the sub primary coil energization permission switch 51 is turned on, and energization to the sub primary coil 111b becomes possible.

  On the other hand, the sub primary coil energization timing determining means 31 uses the sub primary coil energization signal output timing as the sub primary coil energization signal output timing at the same time as or after the sub primary coil energization permission signal Sb1 is supplied to the sub primary coil energization permission switch 51. The primary coil energization single brain generating means 33 is notified, and the sub primary coil energization signal Sb2 generated by the sub primary coil energization signal generating means 33 is supplied to the sub primary coil energization switch 52, and the sub primary coil energization switch 51 is turned on / off. Off control is performed. That is, only when the sub primary coil energization switch 52 is turned on, the sub primary coil energization switch 52 is energized from the DC power supply 4 to the sub primary coil 111a. The power supplied to the sub-primary coil 111b can be finely adjusted by the PWM control that controls ().

  The duty ratio of the sub primary coil energization signal Sb2 generated by the sub primary coil energization signal generation means 33 is adjusted based on the adjustment instruction signal from the comparison determination means 34. The sub primary current detection signal from the sub primary current detection line 62b is input to the comparison determination unit 34, and a highly probable sub primary current detection value that is the value of the sub primary current actually flowing through the sub primary coil 111b is obtained. Can be obtained. Further, the sub primary current target value stored in the sub primary current target value storage unit 35 is supplied to the comparison determination unit 34.

  Then, the comparison / determination means 34 compares the sub primary current detection value with the sub primary current target value, and if the sub primary current detection value is lower than the sub primary current target value, outputs the output increase instruction signal to the sub primary coil energization. When the sub primary current detection value is higher than the sub primary current target value, an output reduction instruction signal is output to the sub primary coil energization signal generation unit 33. The sub primary coil energization signal generation means 33 that has received the output increase instruction signal or the output reduction instruction signal may be controlled to increase or decrease the duty ratio by a predetermined level, but the output increase instruction signal and the output reduction instruction If the control includes the sub primary current energization signal generating means 33 generating the sub primary coil energization signal having a duty ratio corresponding to the increase or decrease, the sub primary current energization signal generating means 33 generates a signal in a short time. The sub primary current detection value can be set to the sub primary current target value.

  The sub primary coil energization signal generating unit 33 that has received the output increase instruction signal from the comparison determination unit 34 increases the power supplied to the sub primary coil 111b by increasing the duty ratio of the sub primary coil energization signal Sb2, Since the primary current is increased, the superimposed magnetic flux generated in the sub-primary coil 111b is strengthened, and the discharge energy superimposed on the secondary side can be increased. On the other hand, the sub primary coil energization signal generation unit 33 that has received the output reduction instruction signal from the comparison determination unit 34 reduces the power supplied to the sub primary coil 111b by reducing the duty ratio of the sub primary coil energization signal Sb2. Since the sub primary current is reduced, the superimposed magnetic flux generated in the sub primary coil 111b is weakened, and the discharge energy superimposed on the secondary side can be reduced.

  The instruction from the comparison determination unit 34 to the sub primary coil energization signal generation unit 33 is an instruction to bring the sub primary current detection value closer to the sub primary current target value, so that although there is a slight increase or decrease, the sub primary current detection value is It is maintained at a constant value substantially equal to the sub primary current target value. Therefore, the superimposed magnetic flux generated in the sub primary coil 111b can be kept substantially constant, and the discharge energy superimposed on the secondary side can also be kept almost constant.

  When the sub primary coil energization signal generation means 33 of the sub primary coil energization control means 30 starts to output the sub primary coil energization signal Sb2, the sub primary coil current detection value based on the sub primary current detection signal is 0V (or reference potential). Therefore, an output increase instruction signal is received from the comparison determination means 34. Even if the sub primary coil energization signal is generated based on the increase amount by the output increase instruction signal, the target sub primary is generated. In some cases, current cannot flow through the sub-primary coil 111b. Therefore, only when the sub primary coil energization signal generation means 33 starts to output the sub primary coil energization signal Sb2, the sub primary coil energization signal having a duty ratio (default setting) determined based on the target sub primary current is generated. You may make it produce | generate. Further, if the secondary primary current target value can be appropriately changed according to the characteristics of the internal combustion engine, versatility can be improved. For example, the secondary primary current target value setting means 36 (shown by a broken line in FIG. 2). It is good also as a structure which can perform setting change of the sub primary current target value memorize | stored in the sub primary current target value memory | storage means 35 easily.

  Next, the ignition coil unit 10, the sub primary coil energization permission switch 51 and the sub primary according to the main primary coil ignition signal Sa, the sub primary coil energization permission signal Sb 1 and the sub primary coil energization signal Sb 2 output from the internal combustion engine drive control device 3. The operation of the coil energization switch 52 will be described based on the waveform diagram of FIG.

  Since it is not necessary to add discharge energy to the secondary side by the superimposed magnetic flux, and in an operating situation in which appropriate discharge characteristics are obtained only by the main primary coil 111a, the internal combustion engine drive control device 3 performs normal discharge control. The main primary coil ignition signal Sa is output from the internal combustion engine drive control device 3 and input to the ignition coil unit 10.

  First, the signal level of the main primary coil ignition signal Sa is changed from L to H at an appropriate timing of the discharge cycle, the main switch 12 is turned on, and the primary current I1a starts to flow. When the signal level of the main primary coil ignition signal Sa is changed from H to L at the timing when the main primary coil energization period Ta elapses, the main switch 12 is turned off and the primary current I1a is cut off, the secondary coil 112 side is turned on. The next current I2 flows.

  The secondary-side voltage increases rapidly due to the primary-side current interruption, and the secondary current I2 increases rapidly. When the voltage applied to the spark plug 2 reaches the discharge voltage, dielectric breakdown occurs in the gap between the electrodes, a discharge spark occurs and the discharge current begins to flow, and the secondary current I2 decreases rapidly. When the voltage drops to some extent, the attenuation becomes gentle, and the secondary current I2 gradually approaches zero. The sudden rise and sudden decrease at the beginning of the flow of the secondary current I2 is considered to be capacitive discharge due to the electrostatic capacity stored in the secondary coil 112, and until the secondary current I2 becomes gentle and returns to zero, This is considered to be induced discharge due to the release of electromagnetic induction energy given to the secondary coil 112 due to current interruption of the main primary coil 111a.

  During the period in which the secondary current is flowing through the secondary coil 112, the signal levels of the sub primary coil energization permission signal Sb1 and the sub primary coil energization signal Sb2 are both kept at L, so that the superimposed current I1b is applied to the sub primary coil 111b. There is no flow. This is normal discharge control performed only by energization control to the main primary coil 111a.

  In an internal combustion engine (for example, a gasoline engine), the fuel in the cylinder is ignited by the discharge spark generated in the spark plug 2 and combustion in the cylinder occurs. However, the discharge current flowing through the spark plug 2 is not sufficient. There is a possibility that a flame nucleus having a size suitable for combustion is not formed, and the necessary kinetic energy cannot be obtained. Since the current value and the maintenance time of the discharge current necessary for suitable in-cylinder combustion vary depending on the structure of the internal combustion engine, the state of the air-fuel mixture, the engine speed, and the like, the internal combustion engine drive control device 3 uses the internal combustion engine. It is determined whether it is desirable to switch from the normal discharge control to the superposed discharge control according to the operation state, and a suitable in-cylinder combustion is realized.

  For example, when the primary primary coil 111a is energized only during the main primary coil 111a, the discharge energy given to the secondary side is insufficient, and a high current period over a relatively long time from the start of discharge is required. The internal combustion engine drive control device 3 performs superimposed discharge control using the sub primary coil 111b. Note that whether or not to perform the superimposed discharge control is determined by the internal combustion engine drive control device 3 based on the secondary current detection value based on the secondary current detection signal, and is necessary to maintain a suitable operating state of the internal combustion engine. In order to realize a high current maintaining period, the sub primary coil energization control means 30 is operated to generate the sub primary coil energization permission signal Sb1 and the sub primary coil energization signal Sb2.

  In the superimposed discharge control, first, the signal level of the main primary coil ignition signal Sa is changed from L to H at an appropriate timing of the discharge cycle, the main switch 12 is turned on, and the primary current I1a starts to flow. When the signal level of the main primary coil ignition signal Sa is changed from H to L at the timing when the main primary coil energization period Ta has elapsed, the main switch 12 is turned off, and the primary current I1a is cut off. A voltage is generated, a discharge spark is generated between the insulating gaps of the spark plug 2, and a secondary current I2 flows.

  Since the superposed discharge is performed after the primary current cut-off timing, the sub primary coil energization control means 30 turns on the sub primary coil energization permission signal Sb1 at the same time as turning off the main primary coil ignition signal Sa, for example. The sub-primary coil energization permission signal Sb1 is turned off at the timing when the coil energization permission period Tb1 has elapsed. That is, when the sub primary coil energization permission signal Sb1 is turned on, the second end 111b2 side of the sub primary coil 111b is in contact with the sub primary coil energization permission switch 51 of the sub primary coil switch unit 5 while the sub primary coil energization permission switch 51 is on. If it is connected to the point GND and a voltage is applied from the first end 111b1 side of the sub primary coil 111b, the sub primary coil 111b can be energized at any time.

  The sub-primary coil energization permission period Tb1 may be set to an arbitrary time, but it is necessary to set at least a period longer than the high current period in which the secondary current I2 needs to be maintained at a high current value. There is. For example, when the main primary coil 111a is energized only during the main primary coil energization period Ta and the main primary current is cut off, the period until the secondary current I2 starts flowing and returns to zero (capacity discharge period + induction discharge period) Is set to the sub-primary coil energization permission period Tb1.

  When the main primary coil 111a is cut off, the secondary current I2 flows suddenly through the secondary coil 1112, and the discharge current begins to flow through the spark plug 2, causing the secondary current I2 to attenuate rapidly. The sub-primary coil energization control means 30 turns on the sub-primary coil energization signal Sb2 at the timing when the rapid decay of I2 ends (for example, the timing when the sub-primary coil energization standby period Tb0 has elapsed). In other words, the sub primary coil energization control means 30 turns on the sub primary coil energization switch 52 of the sub primary coil switch unit 5 at the timing when the sub primary coil energization standby period Tb0 has elapsed, whereby the sub primary coil energization waiting time Tb0 has elapsed. The one end 111b1 side is connected to the DC power supply 4, and the superimposed current I1b is passed through the sub primary coil 111b.

  The sub primary coil energization period Tb2 for performing on / off control of the sub primary coil energization switch 52 by the sub primary coil energization signal Sb2 may be appropriately set within a range not exceeding the sub primary coil energization permission period Tb1. For example, the sub primary coil energization period Tb2 may be set as a period obtained by subtracting the sub primary coil energization standby period Tb0 from the high current period necessary for maintaining stable combustion, or the sub primary coil energization permission period. The sub primary coil energization period Tb2 may be set so as to coincide with the end timing of Tb1.

  Further, the sub primary coil energization control means 30 of the internal combustion engine drive control device 3 can finely adjust the electric power applied to the sub primary coil 111b by PWM control of the sub primary coil energization switch 52. Therefore, the sub primary current I1b can be held substantially at the sub primary current target value until the sub primary coil energization period Tb2 elapses (see the shaded range in the sub primary current I1b in FIG. 3). Thereby, the superimposed magnetic flux generated by the sub primary coil 111b and acting on the secondary coil 112 is kept at a constant amount until the sub primary coil energization period Tb2 elapses.

  As described above, if the sub primary coil energization control means 30 of the internal combustion engine drive control device 3 controls the energization of the sub primary coil 111b, the secondary primary coil 111b continues to the secondary until the sub primary coil energization period Tb2 elapses. Since the amount of discharge energy applied to the coil 112 is kept substantially constant, the secondary current I2 can be increased by a certain amount. That is, in the sub-primary coil energization period Tb2 in the superposed discharge control, the gradient in which the secondary current I2 decreases is substantially the same as the gradient in which the secondary current I2 decreases in the normal discharge control. Since the current value becomes high by the amount of discharge energy given from 111b (the range indicated by the shaded area in the secondary current I2 in FIG. 3), the secondary current I2 can be maintained at a high current for a necessary and sufficient period, and stable. This ensures a high current period and achieves suitable combustion.

  As mentioned above, although embodiment of the ignition device for internal combustion engines which concerns on this invention was described based on the accompanying drawing, this invention is not limited to this embodiment, The structure as described in a claim is not changed. In the range, it may be carried out by diverting known equivalent technical means.

DESCRIPTION OF SYMBOLS 1 Ignition device for internal combustion engines 10 Ignition coil unit 11 Ignition coil 111a Main primary coil 111b Sub primary coil 112 Secondary coil 113 Center core 12 Main switch 15 Case 2 Spark plug 3 Internal combustion engine drive control device 30 Sub primary coil energization control means 4 DC power supply 51 Sub primary coil energization permission switch 52 Sub primary coil energization switch 61a Current detection resistor 61b Secondary voltage detection line 62a Current detection resistor 62b Sub primary voltage detection line

Claims (2)

The primary primary coil that increases the magnetic flux in the positive direction when energized and reduces the magnetic flux in the positive direction by cutting off the current, the sub-primary coil that generates additional magnetic flux in the reverse direction when energized, and one end are connected to the spark plug An ignition coil having a secondary coil in which discharge energy is generated by the action of magnetic fluxes of the main primary coil and the sub primary coil;
Main switch means for switching energization / cutoff to the main primary coil of the ignition coil;
Sub-switch means for switching energization / cut-off to the sub-primary coil;
Sub-primary coil energization permission switch means for permitting energization to the sub-primary coil of the ignition coil;
Sub-primary current detection means for detecting a sub-primary current flowing in the sub-primary coil of the ignition coil;
After the main primary coil is energized by controlling the main switch means, a high voltage is generated on the secondary side of the coil by cutting off the energization to the main primary coil, and a discharge spark is applied to the spark plug at a predetermined timing of the combustion cycle. The sub primary coil energization is permitted to the sub primary coil energization permission switch means for a predetermined superimposition time after the shutoff timing when the energization to the main primary coil is interrupted, and the sub primary coil is controlled by controlling the sub switch means. Ignition control means for performing energization control to,
With
The ignition control means compares the preset sub primary current target value with the sub primary current detection value detected by the sub primary current detection means so that the sub primary current becomes the sub primary current target value. And an internal combustion engine ignition device characterized by controlling energization / interruption to the sub-primary coil.   The said ignition control means adjusts the electric power given to a sub primary coil by carrying out PWM control of the said sub switch means, and was made to increase / decrease the sub primary current which flows into a sub primary coil. Ignition device for internal combustion engine.

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