WO2018229883A1

WO2018229883A1 - Internal combustion engine ignition device

Info

Publication number: WO2018229883A1
Application number: PCT/JP2017/021900
Authority: WO
Inventors: 義文内勢
Original assignee: 日立オートモティブシステムズ阪神株式会社
Priority date: 2017-06-14
Filing date: 2017-06-14
Publication date: 2018-12-20
Also published as: JPWO2018229883A1; JP6739644B2

Abstract

Provided is an internal combustion engine ignition device that is capable of maintaining stable combustion by ensuring a stable high current period through stable supplying of necessary and sufficient discharge energy without deteriorating fuel efficiency. An internal combustion engine ignition device 1 for causing an ignition plug 2 to discharge electricity has an ignition coil 11 formed of a main primary coil 111a that generates a forward magnetic flux when current is passed therethrough, a sub-primary coil 111b that generates a reverse superimposed magnetic flux when current is passed therethrough, and a secondary coil 112 on which the magnetic fluxes of the main primary coil 111a and the sub-primary coil 111b are applied. Thus, an excess/shortage of discharge energy is prevented and stable combustion of an internal combustion engine is efficiently maintained through a feedback control so as to bring an actually measured value of a superimposed current I1b or an actually measured value of a secondary current I2 close to a target value during superimposed discharge control for increasing the discharge energy of the secondary coil 112, by supplying power to the sub-primary coil 111b to generate a superimposed magnetic flux after current to the main primary coil 111b is cut off.

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 obtains good discharge characteristics by increasing the discharge energy generated on the secondary side of the ignition coil in a superimposed manner.

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 primary ignition coil, a high voltage of several kV generated on the secondary side causes dielectric breakdown in the discharge gap of the spark plug. After starting the discharge current from the secondary side of the ignition coil, the primary current of the auxiliary ignition coil connected in parallel with the main ignition coil is cut off, and the DC voltage of several kV generated on the secondary side is added By superimposing, 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 determined by a combination of triangular currents output from the coils, in order to lengthen the high current period, In addition to increasing the ignition phase of the ignition coil, it is necessary to extend the high current period by extending the time for storing sufficient energy in the two ignition coils. Thus, if the energization time to the primary coil is increased in addition to the use of the two ignition coils, there arises a problem that the switching element for enlarging the coil body and controlling the energization control to the primary coil is increased.

Also, as a method of increasing the energy stored in the primary coil without increasing the energization time to the primary coil, a method of increasing the stored energy by increasing the physique of the coil and a method of using a plurality of ignition coils can be considered. However, if a large ignition coil is used or a plurality of ignition coils are used, securing the mounting space becomes a problem. In addition, if a large ignition coil is used or a plurality of ignition coils are used, excessive discharge energy is consumed, which may worsen the fuel consumption.

Therefore, an object of the present invention is to provide an ignition device for an internal combustion engine that can maintain a stable combustion while ensuring a stable high current period by stably supplying necessary and sufficient discharge energy without deteriorating fuel consumption.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a main primary coil in which a forward magnetic flux is increased by energization of a main primary current, and a reverse breaking magnetic flux is generated by interrupting the main primary current; An auxiliary primary coil that generates an additional magnetic flux in the same direction as the interruption magnetic flux by energizing the auxiliary primary current at an arbitrary timing after the generation of the interruption magnetic flux, one end side is connected to the spark plug, and the main primary coil and the auxiliary primary A secondary coil that generates a discharge energy by the action of a magnetic flux generated in the coil, a main switch means for switching between energization and interruption of the main primary coil of the ignition coil, and a connection to the sub primary coil Sub-switch means for switching between energization and cutoff, sub-primary coil energization permission switch means for permitting energization to the sub-primary coil of the ignition coil, the main switch means, Ignition control means for controlling the switch means and the sub primary coil energization permission switch means to generate a discharge spark in the spark plug at a predetermined timing of the combustion cycle, the ignition control means energizing the main primary coil Discharge generated in the secondary coil by allowing the sub primary coil energization permission switch means to energize the sub primary coil and controlling the energization to the sub switch means for a predetermined superimposition time after the shut-off timing of shutting off The energy is increased in a superimposed manner.

The invention according to claim 2 is the ignition device for an internal combustion engine according to claim 1, further comprising sub primary current detection means for detecting a sub primary current flowing in the sub primary coil of the ignition coil, wherein the ignition control is performed. The means compares the preset sub primary current target value with the sub primary current detection value detected by the sub primary current detection means, and brings the sub primary current detection value closer to the sub primary current target value. Sub-primary current feedback control for controlling power supplied to the sub-primary coil is performed.

According to a third aspect of the present invention, in the ignition device for an internal combustion engine according to the second aspect, the ignition control means performs sub primary current feedback control by PWM control of the sub switch means. It is characterized by that.

According to a fourth aspect of the present invention, in the ignition device for an internal combustion engine according to the second or third aspect, the ignition control means includes a sub primary current target value and a sub primary current for each predetermined unit period. The comparison with the detected value is performed, and the supply power control to the sub-primary coil in the next unit period is performed according to the comparison result.

The invention according to claim 5 is the ignition device for an internal combustion engine according to any one of claims 2 to 4, wherein the secondary current that detects the secondary current flowing in the secondary coil of the ignition coil is detected. Current detection means, and the ignition control means compares the preset secondary current target value with the secondary current detection value detected by the secondary current detection means, and compares the secondary current detection value The sub primary current target value is set and changed so as to approach the secondary current target value.

According to a sixth aspect of the present invention, in the internal combustion engine ignition device according to the fifth aspect, the secondary current target value is a secondary current target upper limit value determined in advance as an allowable upper limit of the secondary current. And a predetermined secondary current target lower limit value as a lower limit of the allowable secondary current, the secondary current target upper limit value and the secondary current target lower limit value are compared with the secondary current detection value, and the secondary current If the secondary current detection value is higher than the target upper limit value, change the setting of the sub primary current target value to lower the secondary current, and if the secondary current detection value is lower than the secondary current target lower limit value Is characterized in that the sub primary current target value is set and changed so as to increase the secondary current.

The invention according to claim 7 is the internal combustion engine ignition device according to

claim

5 or 6, wherein the ignition coil discharges between the main primary coil of the ignition coil and the main switch means. Primary coil voltage detection means for detecting a primary side voltage generated during the continuation, the ignition control means, when the primary coil voltage rises above a predetermined voltage earlier than a predetermined inclination angle, the secondary current target The setting is changed so as to increase the value.

According to the ignition device for an internal combustion engine according to the present invention, by providing the sub primary coil magnetic flux generation state switching means, the superimposed discharge control before the ignition timing and the superimposed discharge control after the ignition timing can be performed. The necessary and sufficient discharge energy is superimposed from the secondary primary coil to the secondary coil to ensure a stable high current period without increasing the energization time of the main primary coil, thereby realizing suitable combustion. Moreover, a high fuel efficiency improvement effect can be expected by properly using the pre-ignition timing superimposed discharge control and the post-ignition timing superimposed discharge control according to the operating conditions. In addition, since a plurality of coils and a booster circuit are not required, an increase in the size of the ignition coil and a significant increase in cost can be suppressed.

1 is a schematic configuration diagram showing a first embodiment of an ignition device for an internal combustion engine according to the present invention. It is a wave form diagram showing typically each part waveform in a combustion cycle when performing normal discharge control and superposition discharge control by the internal combustion engine ignition device concerning a 1st embodiment. (A) is the wave form diagram which showed typically the sub primary coil energization signal which a control means produces | generates when a sub primary current detection value corresponds with a sub primary current target value. (B) is a waveform diagram schematically showing a sub primary coil energization signal generated by the control means when the sub primary current detection value deviates from the sub primary current target value. (A) is a waveform diagram schematically showing the secondary primary current target value generated by the control means when the secondary current detection value is in the range of the secondary current target upper limit value and the secondary current target lower limit value. is there. (B) is a waveform diagram schematically showing the secondary primary current target value generated by the control means when the secondary current detection value exceeds the secondary current target upper limit value. (C) is a waveform diagram schematically showing the secondary primary current target value generated by the control means when the secondary current detection value falls below the secondary current target lower limit value. It is a schematic block diagram which shows 2nd Embodiment of the ignition device for internal combustion engines which concerns on this invention. It is a wave form diagram showing typically each part waveform in a combustion cycle when performing maintenance and change of a secondary current target value according to a primary coil voltage in an internal combustion engine ignition device concerning a 2nd embodiment.

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 internal combustion engine ignition device 1 according to a first embodiment of the present invention. An ignition coil unit 10 that generates a discharge spark in one ignition plug 2 provided for each cylinder of the internal combustion engine, An internal combustion engine drive control device 3 having an ignition control means 31 for outputting an ignition signal Si or the like for instructing the operation timing of the ignition coil unit 10 at an appropriate timing, a DC power source 4 such as a vehicle battery, a first sub switch element 51 The second sub switch element 52 and the like.

In the internal combustion engine ignition apparatus 1 shown in the present embodiment, the ignition control means 31 is included in the internal combustion engine drive control apparatus 3 that comprehensively controls the internal combustion engine of the automobile, but is not limited thereto. It is not something. For example, the ignition signal generated by the ignition signal generation function of the normal internal combustion engine drive control device 3 is received, and appropriate control signals are sent to the ignition coil unit 10 and the first and second

sub switch elements

51, 52. Ignition control means for outputting to may be provided separately.

The ignition coil unit 10 includes, for example, an ignition coil 11, a main switch element 12, a bypass line 13 provided in parallel with the main switch element 12, rectifying means 14 provided on the bypass line 13, and the like in a case 15 having a required shape. This unit is a unitary structure. A high voltage terminal 151 and a connector 152 are provided at appropriate positions of the case 15, and the spark plug 2 is connected via the high voltage terminal 151, and the connector 152 (for example, the first connection terminal 152 a to the sixth connection terminal 152 f is connected to the case 15. Are connected to the internal combustion engine drive control device 3, the DC power source 4 such as a vehicle battery, the first and second

sub switch elements

51 and 52, and the ground point GND.

The ignition coil 11 includes a primary primary coil 111a (for example, 90 turns), a secondary primary coil 111b (for example, 60 turns), and a secondary coil 112 (for example, 9000 turns). The ignition coil 11 causes the magnetic flux generated in the main primary coil 111a and the sub primary coil 111b to act on the secondary coil 112. For example, the main primary coil 111a and the sub primary coil 111b are arranged so as to surround the center core 1113. In addition, the secondary coil 112 is arranged outside thereof.

One end of the main primary coil 111a is connected to the DC power supply 4 through, for example, the second connection terminal 152b, and a power supply voltage VB + (for example, 12V) is applied. The other end of main primary coil 111a is connected to ground point GND via main switch element 12 and fifth connection terminal 152e.

The main switch element 12 is a main switch means for energizing / cutting off the main primary coil 111a, and is configured by using, for example, an IGBT (Insulated Gate Bipolar Transistor). That is, the ignition coil unit 10 has a unit structure in which an ignition coil and an igniter are sealed in the case 15. The gate G, which is the control terminal of the main switch element 12, is connected to the internal combustion engine drive control device 3 through, for example, the fourth connection terminal 152d, and is ON / OFF controlled by the ignition signal Si generated by the ignition control means 31. The

As described above, when the main switch element 12 is turned on by the ignition signal Si and the main primary coil 111a is energized, the main primary current I1a flows to increase the forward magnetic flux, and the main switch element 12 is turned off. When the main primary current I1a is cut off, the forward magnetic flux is suddenly reduced (apparently, a breaking magnetic flux opposite to the forward magnetic flux is generated). As a result, a high voltage is generated on the secondary coil 112 side, a discharge spark is generated between the discharge gaps of the spark plug 2, and a secondary current I2 flows. In this way, the control for discharging the spark plug 2 by energization / cutoff control for the main primary coil 111a is hereinafter referred to as normal discharge control.

The secondary coil 112 has one end connected to the spark plug 2 via the high-voltage terminal 151 and the other end connected to the ground point GND via the sixth connection terminal 152f. Note that a current detection resistor 61 is provided between the sixth connection terminal 152f and the ground point GND, and a secondary current detection signal line provided between the sixth connection terminal 152f and the current detection resistor 621 is provided as a secondary. The current detection signal Di2 is supplied to the internal combustion engine drive control device 3. That is, the current detection resistor 61 and the secondary current detection signal line function as secondary current detection means for detecting the secondary current I2 flowing through the secondary coil 112.

Next, the sub primary coil 111b whose energization / cutoff timing is controlled by the first and second

sub switch elements

51 and 52 will be described.

The sub primary coil 111b generates, for example, an additional magnetic flux in the same direction as the interrupting magnetic flux when energized in the direction from the first end 111b1 which is one end of the sub primary coil 111b to the second end 111b2 which is the other end. The first end 111b1 of the sub primary coil 111b is connected to the first sub switch element 51 via, for example, the first connection terminal 152a, and the second end 111b2 of the sub primary coil 111b is connected to, for example, the third connection terminal 152c. To the second sub switch element 52.

Therefore, when the first and second

sub switch elements

51 and 52 have the first end 111b1 of the sub primary coil 111b on the power supply side and the second end 111b2 on the ground side, the sub primary coil 11b is energized in the first direction. The Rukoto. Conversely, when the first and second

sub-switch elements

51 and 52 make the second end 111b2 of the sub-primary coil 111b the power supply side and the first end 111b1 the ground side, the sub-primary coil 11b is energized in the second direction. Will be.

In addition, the 1st direction and the 2nd direction in the sub primary coil 111b are decided by the arrangement | positioning state with the main primary coil 111a. For example, when the winding direction of the sub primary coil 111b and the winding direction of the main primary coil 111b are arranged to be the same, the same direction as the energization direction to the main primary coil 111b may be energized as the first direction. A forward magnetic flux is generated in the secondary primary coil 111b. On the other hand, when the winding direction of the sub primary coil 111b and the winding direction of the main primary coil 111b are reversed, the first primary coil 111b is energized with the opposite direction to the energization of the main primary coil 111b. In this case, a forward magnetic flux is generated.

When the sub primary coil 111b configured as described above is energized in the first direction at the same timing as the normal discharge control by the main primary coil 111a described above, the same forward magnetic flux as that of the main primary coil 11a is generated. After that, if the current supply to the sub primary coil 111b is cut off at the same timing as the normal discharge control, the forward magnetic flux of the main primary coil 111a and the sub primary coil 111b rapidly decreases at the same time, so that the discharge energy given to the secondary side is increased. Can do. That is, the forward primary magnetic flux is generated by the sub primary coil 111b before the ignition timing (before the energization interruption timing to the main primary coil 111a), and the energization interruption to the sub primary coil 111b is performed simultaneously with the main primary coil 111a. For example, the discharge energy can be superimposed on the secondary coil 112 by the secondary primary coil 111b.

In addition, if the secondary primary coil 111b is energized in the second direction at an appropriate timing after the ignition timing (after the energization cut-off timing to the main primary coil 111a), the magnetic flux in the reverse direction (high on the secondary side) is obtained. (The magnetic flux in the same direction as the magnetic field that generated the voltage) is generated, and the secondary side magnetic field can be prevented from being attenuated and the secondary side electromotive force to be lowered. The secondary current I2 can be kept high until That is, if the secondary primary coil 111b generates a reverse magnetic flux after the ignition timing and causes it to act on the secondary coil 112, the secondary primary coil 111b can superimpose discharge energy on the secondary coil 112.

It should be noted that the timing of cutting off the current in the second direction for the sub-primary coil 111b is when a sufficient and sufficient time has passed to maintain the secondary current I2 at a high current necessary for suitable combustion in the cylinder. If the second direction energization to the sub primary coil 111b is continued for a longer time than that, the fuel consumption is worsened. Such desirable energization / cutoff timing for the sub-primary coil 111b is not fixed, but varies depending on the structure of the internal combustion engine, the characteristics of the ignition coil, the operating conditions, and the like. A setting value or setting information suitable for 1 may be stored in the ignition control means 31 of the internal combustion engine drive control device 3 in advance.

Further, when the second direction energization to the sub primary coil 111b is cut off, the counter electromotive force acts on the main primary coil 111a, so that the reverse direction in which the current in the direction opposite to that of the normal primary current I1 is to flow. The voltage is applied between the collector and the emitter of the main switch element 12, and there is a risk that the main switch element 12 may break down or the deterioration of the main switch element 12 may be accelerated. Therefore, a bypass line 13 is provided in parallel with the main switch element 12, and rectifying means 14 (for example, the collector side of the main switch element 12) is forwardly directed from the ground point GND side of the bypass line 13 toward the ignition coil 11 side. And a diode having an anode connected to the emitter side of the main switch element 12).

Next, a sub primary coil capable of switching between a forward magnetic flux generation state in which the first primary coil 111b can be energized in the first direction and a reverse magnetic flux generation state in which the sub primary coil 111b can be energized in the second direction can be switched. A configuration example of the first and second

sub switch elements

51 and 52 serving as magnetic flux generation state switching means will be described. The first and second

sub switch elements

51 and 52 include a first sub switch element 51, a second sub switch element 52, a third sub switch element 53, and a fourth sub switch element 54.

The first sub switch element 51 functions as sub switch means for switching between energization / cutoff from the DC power source 4 to the sub primary coil 111b. For example, the first sub switch element 51 is configured using a power MOS-FET having high-speed switching characteristics, and the drain D of the first sub switch element 51 is on the DC power supply 4 side, and the source S of the first sub switch element 51 is. Is connected to the second end 111b2 side of the sub primary coil 111b, and the sub primary coil energization signal Sd from the ignition control means 31 is input to the gate G of the first sub switch element 51. Accordingly, the first sub switch element 51 is turned ON / OFF in response to the ON / OFF of the sub primary coil energization signal Sd input from the ignition control means 31 to the first sub switch element 51, and the first of the sub primary coil 111b. The power supply voltage VB + is applied or cut off from the DC power supply 4 to the end 111b1. In order to increase the voltage applied to the sub-primary coil 111b, a higher voltage DC power supply may be used instead of the VB + DC power supply 4. Alternatively, a booster circuit 7 (indicated by a two-dot chain line in FIG. 1) may be provided to increase the voltage applied to the sub primary coil 111b.

The second sub-switch element 52 functions as a sub-primary coil energization permission unit that switches the second end 111b2 side of the sub-primary coil 111b to the ground point GND so that the sub-primary coil 111b can be energized. For example, the second sub switch element 52 is configured by using a power MOS-FET having high-speed switching characteristics, and the drain D of the second sub switch element 52 is connected to the second end 111b2 side of the sub primary coil 111b. The source S of the switch element 52 is connected to the ground point GND side, and the sub primary coil energization permission signal Sp from the ignition control means 31 is input to the gate G of the second sub switch element 52. Therefore, the second sub-switch element 52 is turned on / off in response to the ON / OFF of the sub-primary coil energization permission signal Sp input from the ignition control means 31 to the second sub-switch element 52, and the second primary switch 111b The two ends 111b2 are connected to the ground point GND. A current detection resistor 62 is provided between the second sub switch element 52 and the ground point GND, and a sub primary current detection signal line provided between the second sub switch element 52 and the current detection resistor 62 is provided. Thus, the sub primary current detection signal Di1s is input to the internal combustion engine drive control device 3. That is, the current detection resistor 62 and the sub primary current detection signal line function as sub primary current detection means for detecting the sub primary current flowing through the sub primary coil 111b.

Here, a control example by the ignition control means 31 in the internal combustion engine ignition device 1 of the first embodiment will be described with reference to FIG.

The first stage of FIG. 2 shows normal discharge control, and is basic control for giving discharge energy to the secondary coil 112 using only the main primary coil 111a during one combustion cycle. First, when the ignition signal Si is turned ON at a predetermined timing during the combustion cycle, the main switch element 12 is turned ON and the main primary current I1a flows. As time elapses from energization to the main primary coil 111a, the main primary current I1a increases until reaching the saturation current, and energy is accumulated in the main primary coil 111a. When the ignition signal Si is turned OFF at the ignition timing (when the signal level is changed from H to L), an electromotive force corresponding to the energy accumulated in the main primary coil 111a is generated on the secondary side, and the secondary current I2 is While flowing, dielectric breakdown occurs between the electrodes of the spark plug 2 to generate a discharge spark in the cylinder (capacitive discharge). Thereafter, the discharge (inductive discharge) due to the release of the magnetic energy applied to the secondary coil 112 continues for about 0.5 to 2.5 ms, but the electromotive force generated in the secondary coil 112 gradually weakens, and the secondary current I2 Will also decay.

The subsequent stage of FIG. 2 shows superimposed discharge control. After the ignition timing by energization / cutoff of the main primary coil 111a, the first and second

sub switch elements

51 and 52 are controlled to energize the sub primary coil 111b. This control starts and supplies the secondary side with sufficient energy necessary to maintain the induction discharge from the secondary primary coil 111b.

First, when the ignition signal Si is turned ON at a predetermined timing during the combustion cycle, the main switch element 12 is turned ON and the main primary current I1a flows. As time elapses from energization to the main primary coil 111a, the main primary current I1a increases until reaching the saturation current, and energy is accumulated in the main primary coil 111a. When the ignition signal Si is turned OFF at the ignition timing (when the signal level is changed from H to L), an electromotive force corresponding to the energy accumulated in the main primary coil 111a is generated on the secondary side, and the secondary current I2 is As it flows, dielectric breakdown occurs between the electrodes of the spark plug 2, and a discharge spark is generated in the cylinder (capacitive discharge).

After the capacitive discharge is generated in the spark plug 2 and the discharge current starts to flow as described above, for example, the timing of transition from the capacitive discharge to the induction discharge (for example, the predetermined superimposed discharge standby time Tpre from the OFF of the ignition signal Si is At the elapsed timing), the ignition control unit 31 turns on the sub primary coil energization permission signal Sp (for example, the signal level from L to H) and turns on the sub primary coil energization signal Sd. In the example shown in FIG. 2, the power supplied to the sub primary coil 111b is adjusted by performing PWM control that changes the duty ratio of the sub primary coil energization signal Sd.

The sub primary current (hereinafter referred to as the superimposed current I1b) flowing through the sub primary coil 111b gradually increases until reaching the saturation current, and the reverse magnetic flux (the magnetic field generated in the secondary coil 112 after the ignition timing) The superimposed magnetic flux in the same direction also increases (indicated by shading in the superimposed current waveform in FIG. 2). Therefore, the superimposed magnetic flux generated in the secondary primary coil 111b acts on the secondary coil 112 so as to compensate for the decrease in the secondary current I2 due to the electromagnetic energy emission of the secondary coil 112, and the secondary current I2 is a high current. The high current period suitable for in-cylinder combustion can be effectively extended for a long time (indicated by the hatching in the secondary current waveform in FIG. 2).

Thereafter, when a high current maintenance period (high current period) sufficient for suitable in-cylinder combustion has elapsed, the ignition control means 31 turns off the sub primary coil energization permission signal Sp and the sub primary coil energization signal Sd. As a result, the reverse magnetic flux caused by the secondary primary coil 111b does not act on the secondary coil 112, and thereafter, a low secondary current I2 due to only the electromagnetic energy emission of the secondary coil 112 flows, and eventually the secondary current I2 Will return to zero. The energization permission period Tb1 for turning on the sub primary coil energization permission signal Sp and the energization period Tb2 for supplying power from the DC power supply 4 to the sub primary coil 111b may be the same period, or the energization permission period Tb1. However, it may be slightly longer than the energization period Tb2.

As described above, when the ignition control means 31 performs the superimposed discharge control, the discharge energy applied to the secondary coil 112 is increased without increasing the ON time of the ignition signal Si, and the discharge flowing between the electrodes of the spark plug 2. The period during which the current can be maintained at a high current can be extended. In addition, the superimposed magnetic flux applied from the secondary primary coil 111b to the secondary coil 112 is sufficient to generate and maintain a sufficiently high current necessary for suitably maintaining in-cylinder combustion. The energy required for energization can be kept low, which is effective for improving fuel efficiency.

In addition, in the internal combustion engine ignition device 1 of the present embodiment, since the ignition control means 31 can perform PWM control of the first sub switch element 51 by the sub primary coil energization signal Sd, the sub primary coil 111b in the superimposed discharge control. By appropriately increasing / decreasing the superimposed current I1b flowing through the secondary battery, appropriate discharge energy without excess or deficiency can be given to the secondary side, and further improvement in fuel efficiency can be expected. In order to do this, the ignition control means 31 stores a preset secondary primary current target value, and is obtained from the secondary primary current detection value (sub primary current detection signal Di1s) detected by the secondary primary current detection means. The value of the superimposed current I1b) is compared with the sub primary current target value, and sub primary current feedback control is performed to control the power supplied to the sub primary coil so that the sub primary current detection value approaches the sub primary current target value. It is.

As feedback control for bringing the actually measured value close to the target value, various known techniques can be applied. However, in the internal combustion engine ignition device 1 of the present embodiment, the ignition control means 31 to the first sub switch element. The duty ratio of the sub primary coil energization signal Sd output to 51 can be changed every predetermined unit period Tu, and the next unit period is determined according to the comparison result between the sub primary current detection value and the sub primary current target value. The duty ratio of the sub primary coil energization signal Sd in Tu is increased or decreased. An example of this feedback control will be described with reference to FIG. FIG. 3A shows a case where the sub primary current detection value substantially coincides with the sub primary current target value, and FIG. 3B shows the difference between the sub primary current detection value and the sub primary current target value. The case where feedback control is performed because it is large enough to require correction is shown.

Note that various known methods can be applied to the error comparison method between the target value and the detected value. However, in this example, the sub primary current detected value is the sub primary current target value at approximately the middle of the unit period Tu. If it agrees with the above, it is determined that the target discharge energy is generated. In addition, if the sub primary current detection value has reached the sub primary current target value in the previous period of the unit period Tu, or if the sub primary current detection value has exceeded the sub primary current target value before the start of the unit period Tu, It is determined that excessive discharge energy is generated. Conversely, the sub primary current detection value finally reaches the sub primary current target value in the subsequent period of the unit period Tu, or the sub primary current detection value must not reach the sub primary current target value even after the unit period Tu has elapsed. In this case, it is determined that the necessary discharge energy is not generated.

3A, in order to output the secondary primary coil energization signal Sd having a normal duty ratio during the first unit period Tu1, the secondary primary current detection value obtained as the superimposed current I1b during that time is the first primary period Tu1. Since it coincides with the sub primary current target value near the middle of the one unit period Tu1, the sub primary coil energization signal Sd having the normal duty ratio is output also in the next second unit period Tu2. Similarly, in the second to fourth unit periods Tu2 to Tu4, the sub primary current detection value coincides with the sub primary current target value in the vicinity of the middle of each period, so that the normal duty ratio is also obtained in the next unit period. The sub primary coil energization signal Sd is output.

Since the secondary primary current target value is originally set to obtain a good superimposed current I1b in order to stably generate discharge sparks in the spark plug 2, the secondary primary current target value is as shown in FIG. Ideally, the primary current detection value coincides with the sub primary current target value and appropriate discharge energy can be superimposed, but the ideal superimposed current I1b cannot be obtained due to the vehicle driving environment, engine load, etc. There is also. In such a case, by monitoring the actual superimposed current I1b and performing feedback control so as to obtain the ideal superimposed current I1b, excess or deficiency of energy due to the superimposed discharge can be eliminated.

3B, in order, in the first unit period Tu1, a sub primary coil energization signal Sd having a normal duty ratio is output, and the sub primary current detection value obtained as the superimposed current I1b during that time is the first unit period Tu1. Since it coincides with the sub primary current target value slightly later in one unit period Tu1, it is determined that the superimposed current I1b is lower than the ideal current value, and the duty ratio is increased in the next second unit period Tu2. The sub primary coil energization signal Sd is output.

When the duty ratio is increased or decreased, a high duty ratio output and a low duty ratio output are respectively determined in advance, and when the duty ratio is increased, the high duty ratio output is applied to the sub primary coil energization signal Sd. When the duty ratio is lowered, the low duty ratio output may be applied to the sub primary coil energization signal Sd, or the duty ratio according to the error value between the sub primary current target value and the sub primary current detection value may be set. A pulse signal may be generated and applied to the sub primary coil energization signal Sd.

Even in the second unit period Tu2 in which the sub-primary coil energization signal Sd with an increased duty ratio is output, the sub-primary current detection value coincides with the sub-primary current target value in a slightly later period, so that the superimposed current I1b is still present. Is lower than the ideal current value, and the sub-primary coil energization signal Sd with an increased duty ratio is output even in the next third unit period Tu3. In the third unit period Tu3 in which the sub-primary coil energization signal Sd with an increased duty ratio is output, the sub-primary current detection value substantially coincides with the sub-primary current target value in the vicinity of the middle. It is determined that I1b is supplied, and the sub-primary coil energization signal Sd having a normal duty ratio is output in the next fourth unit period Tu4. In the fourth unit period Tu4 in which the sub primary coil energization signal Sd having the normal duty ratio is output, the sub primary current detection value slightly matches the sub primary current target value in the previous period, so the superimposed current I1b Is higher than the ideal current value, and in the next fifth unit period Tu5, the sub primary coil energization signal Sd with a reduced duty ratio is output. As a result, in the fifth unit period Tu5, the superimposed current I1b can be suppressed to an ideal current value.

As described above, the ignition control means 31 compares the sub primary current target value and the sub primary current detection value for each predetermined unit period, and applies the sub primary coil 111b in the next unit period according to the comparison result. If the supplied power control is performed, the superimposed current I1b having an ideal waveform set as the sub primary current target value can be obtained.

However, the ideal secondary current I2 is not always obtained with the waveform of the superimposed current I1b set as the sub primary current target value. Therefore, the ignition control means 31 compares the preset secondary current target value with the secondary current detection value detected by the secondary current detection means, and converts the secondary current detection value to the secondary current target value. The sub primary current target value is set and changed so as to be close to each other.

As feedback control for bringing the measured value of the secondary current closer to the target value of the secondary current, various known techniques can be applied. However, in the internal combustion engine ignition device 1 of the present embodiment, the secondary control is possible. The sub primary current target value is controlled to be changed depending on whether the actual measured value of the secondary current is within the allowable range of the target current value or exceeds the threshold value of the allowable range. For example, using a secondary current target upper limit value determined in advance as an upper limit of an allowable secondary current and a secondary current target lower limit value set in advance as a lower limit of an allowable secondary current, the secondary current target upper limit value And the secondary current target lower limit value is compared with the secondary current detection value, and if the secondary current detection value is higher than the secondary current target upper limit value, the sub primary current target value is changed to lower the secondary current. When the secondary current detection value is lower than the secondary current target lower limit value, the sub primary current target value is set and changed so as to increase the secondary current. In this way, the sub primary current target value is changed so that the target secondary current I2 is obtained, and a sub primary coil energization signal Sd that brings the superimposed current I1b closer to the changed sub primary current target value is output. Will be.

An example of this feedback control will be described with reference to FIG. FIG. 4A shows the case where the detected secondary current value substantially matches the secondary current target value (when it falls within the allowable range between the secondary current target upper limit value and the secondary current target lower limit value). FIG. 4B shows a case where the secondary current detection value exceeds the secondary current target upper limit value and includes a situation where the sub primary current target value change condition is satisfied, and FIG. The case where the secondary current detection value falls below the secondary current target lower limit value and the situation where the sub primary current target value change condition is satisfied is shown.

In FIG. 4A, in any of the first unit period Tu1 to the seventh unit period Tu7, the secondary current detection value is an allowable range between the secondary current target upper limit value and the secondary current target lower limit value. Therefore, the sub primary current target value changing condition is not satisfied, and a preset sub primary current target value is used. Note that the sub primary current target value, which is the default setting, is such that the sub primary current target value increases step by step by the reference level every time the reference period Tu elapses. For example, the first reference period Tu1 is output level 1, the second reference period Tu2 is output level 2, the third reference period Tu3 is output level 3, the fourth reference period Tu4 is output level 4, and the fifth reference period Tu5 is output level. 5. The preset sub-primary current target value is such that the output level increases stepwise, such as output level 6 in the sixth reference period Tu6, output level 7 in the seventh reference period Tu7, and so on.

In FIG. 4B, when the secondary current detection value exceeds the secondary current target upper limit value, the sub primary current target value changing condition is satisfied, and control is performed to change the sub primary current target value. First, in the first reference period Tu1, the output level 1 is set according to the preset sub-primary current target value. During this first reference period Tu1, the actually measured value of the secondary current I2 is a secondary value. Since the current target upper limit value has been exceeded, the secondary current I2 is reduced to fall within the allowable range, so that the output level 1 is not changed to the output level 2 in the next second reference period Tu2. In the second reference period Tu2 that remains at the output level 1, the measured value of the secondary current I2 still exceeds the secondary current target upper limit value, so that the secondary current I2 is further reduced to be within the allowable range. In the next third reference period Tu3, the output level is kept at 1 without shifting to the output level 2.

In the third reference period Tu3 that remains at the output level 1, the measured value of the secondary current I2 falls below the secondary current target upper limit value and falls within the allowable range, so that the output level 2 is reached in the next fourth reference period Tu4. Transition. In the fourth reference period Tu4 that is increased to the output level 2, the secondary current detection value is within the allowable range between the secondary current target upper limit value and the secondary current target lower limit value. The condition is not satisfied, and the target value is raised to the output level 3 in the next fifth reference period Tu5. In the fifth reference period Tu5 that is increased to the output level 3, the measured value of the secondary current I2 again exceeds the secondary current target upper limit value, so that the secondary current I2 is reduced to fall within the allowable range. In 6 reference period Tu6, it does not shift to output level 4 but remains at output level 3.

In the sixth reference period Tu6 that remains at the output level 3, the actually measured value of the secondary current I2 falls below the upper limit value of the secondary current target and falls within the allowable range, so that the output level 4 is reached in the next seventh reference period Tu7. Transition. In the subsequent seventh reference period Tu7 to ninth reference period Tu9, the secondary current detection value is within the allowable range between the secondary current target upper limit value and the secondary current target lower limit value. Since the current target value changing condition is not satisfied and the output level is increased by 1 for each reference period Tu, the target value is set in the seventh reference period Tu7 to the ninth reference period Tu9 as in the case of the default primary current target value. The output level goes up step by step.

In FIG. 4C, when the secondary current detection value falls below the secondary current target lower limit value, the sub primary current target value changing condition is satisfied, and control is performed to change the sub primary current target value. First, in the first reference period Tu1, the output level 1 is set according to the preset sub-primary current target value. During this first reference period Tu1, the actually measured value of the secondary current I2 is a secondary value. Since the current target upper limit value has been exceeded, the secondary current I2 is reduced to fall within the allowable range, so that the output level 1 is not changed to the output level 2 in the next second reference period Tu2. In the second reference period Tu2 that remains at the output level 1, the measured value of the secondary current I2 falls below the secondary current target upper limit value and falls within the allowable range, so the sub primary current target value change condition is not satisfied, In the next third reference period Tu3, the target value is raised to the output level 2.

In the third reference period Tu3 increased to the output level 2, the measured value of the secondary current I2 has fallen below the secondary current target lower limit value. Therefore, in order to increase the secondary current I2 to be within the allowable range, In the reference period Tu4, the target value is increased by two stages and shifted to output level 4. In the fourth reference period Tu4 increased to the output level 4, the measured value of the secondary current I2 exceeds the secondary current target lower limit value and falls within the allowable range. Therefore, the target value is set to one step in the next fifth reference period Tu7. And shift to output level 5. In the subsequent fifth reference period Tu5 to ninth reference period Tu9, the secondary current detection value is within the allowable range between the secondary current target upper limit value and the secondary current target lower limit value. Since the current target value changing condition is not satisfied and the output level is increased by 1 for each reference period Tu, the output level is output in the fifth reference period Tu5 to the ninth reference period Tu9 as in the case of the default primary current target value. Goes up step by step.

The sub primary current target value whose setting has been changed as described above is compared with the sub primary current detection value as described above, and the sub primary current energization signal Sd is generated. That is, when the setting is changed to an output level higher than the default set primary primary current target value, the secondary primary coil energization signal Sd with an increased duty ratio is output, so that the superimposed current I1b is increased and the secondary side is increased. It is possible to increase the discharge energy applied to the gas and to ensure a high current period of the secondary current I2 and realize suitable combustion. Further, when the setting is changed to an output level lower than the default set primary primary current target value, the secondary primary coil energization signal Sd with a reduced duty ratio is output, so the superimposed current I1b is kept low and the secondary current is reduced. The current I2 can be kept low, and a high fuel efficiency improvement effect can be expected.

In the above-described internal combustion engine ignition device 1 according to the first embodiment, necessary and sufficient discharge energy is obtained by causing the superimposed magnetic flux generated by the sub primary coil 111b provided separately from the main primary coil 111a to act on the secondary coil 112. Is applied to the secondary side, and feedback control using measured values of the superimposed current I1b and the secondary current I2 can be performed in order to make the superimposed discharge control more efficient.

However, in the discharge control of the spark plug 2, the secondary voltage applied to the ignition coil 11 represents the discharge state of the spark plug 2 most. The secondary voltage is, for example, a voltage from the high-voltage terminal 151 to the ground point GND, and this voltage is simulated by the main primary coil 111a1 via the secondary coil 112. In other words, when the voltage of the main primary coil 111a1 can be detected when the main switch element 12 is in the non-operating state, the state of the secondary voltage can be known, so that feedback control according to the state of the secondary voltage is possible. For example, in the case of ultra lean combustion, the withstand voltage between the electrodes of the spark plug 2 is higher than a predetermined voltage, so that initial ignition is performed at a high voltage higher than the predetermined voltage, but sufficient discharge to grow the initial flame. If no current is supplied, the initial flame will not grow and will misfire due to blow-off. In such a case, in order to grow the initial flame independently, it is necessary to control to increase the current value in the high current period.

Therefore, in the internal combustion engine ignition device 1 ′ of the second embodiment shown in FIG. 5, the main primary coil 111 a and the main switch element 12 of the ignition coil unit 10 ′ (but the main primary coil rather than the bypass line 13). 111a side) is provided with a primary coil voltage acquisition line 16 as primary coil voltage detection means for detecting the primary voltage of the ignition coil 11, and a primary coil voltage detection signal is sent to the ignition control means 31 via the seventh connection terminal 152g. Dv1 is supplied. The detected value of the primary coil voltage input from the primary coil voltage detection signal Dv1 is that the discharge of the ignition coil 2 continues after the main switch element 12 is turned off and discharge energy is supplied to the secondary side of the coil. During this time, the voltage waveform simulates the secondary voltage waveform (see, for example, the waveform of the primary coil voltage detection signal Dv1 and the waveform of the secondary voltage in FIG. 6).

Therefore, the ignition control means 31 changes the setting so as to increase the secondary current target value when the detected value of the primary coil voltage rises above the predetermined voltage earlier than the predetermined inclination angle. For example, when the change condition for increasing the secondary current target value is not satisfied (when the voltage rises to a predetermined voltage below a predetermined inclination angle), good combustion is maintained at the default secondary current target value. Therefore, the default secondary current target value is maintained, the secondary primary current target value is changed and the secondary primary coil energization signal Sd is generated based on the secondary current target value (see the previous stage in FIG. 6). . On the other hand, when the change condition for increasing the secondary current target value is satisfied (when the voltage rises to a predetermined voltage earlier than a predetermined inclination angle), good combustion cannot be maintained with the default secondary current target value. Therefore, change the default secondary current target value to a higher secondary current target value (e.g., without changing the allowable range between the secondary current target upper limit value and the secondary current target lower limit value). Secondary current target correction upper limit value and secondary current target correction lower limit value, which are set to equally increase the secondary current target upper limit value and secondary current target lower limit value, and set the secondary primary current target based on this secondary current target correction value. Value change setting control and sub primary coil energization signal Sd generation control are performed (see the subsequent stage of FIG. 6).

Therefore, according to the internal combustion engine ignition device 1 ′ according to the second embodiment, it is possible to perform appropriate feedback control according to the state of the secondary voltage applied to the ignition coil 2, thereby realizing even better combustion. Along with this, a high fuel efficiency improvement effect can be expected.

The internal combustion

engine ignition devices

1, 1 ′ according to the first and second embodiments described above all show only one cylinder, but in the case of an internal combustion engine composed of a plurality of cylinders, the first, Second

sub-switch elements

51 and 52, sub-primary current detection means, secondary current detection means and the like may be provided, or all of the first and second

sub-switch elements

51 and 52 corresponding to each cylinder may be provided as a single unit. A general unit housed in a case may be used, and the general unit may be connected to the ignition coil units 10 and 10 'of each cylinder.

As mentioned above, although several 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 these embodiment, As described in a claim You may implement by diverting a well-known equivalent technical means in the range which does not change a structure.

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 12 Main switch element 2 Spark plug 3 Internal combustion engine drive control device 31 Ignition control means 4 DC power source 51 First sub switch Element 52 Second sub switch element

Claims

The primary primary current increases the forward magnetic flux and the primary primary current is interrupted to generate the reverse primary magnetic flux, and the secondary primary current is energized at any time after the generation of the primary magnetic flux. And a secondary primary coil that generates an additional magnetic flux in the same direction as the interrupting magnetic flux, and a secondary end that is connected to a spark plug at one end, and the magnetic flux generated in the primary primary coil and the secondary primary coil acts to generate discharge energy. An ignition coil having a 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;
Ignition control means for controlling the main switch means, sub switch means, and sub primary coil energization permission switch means to generate a discharge spark in the spark plug at a predetermined timing of the combustion cycle;
With
The ignition control means allows the sub-primary coil energization permission switch means to energize the sub-primary coil for a predetermined superimposition time after the shut-off timing when the energization to the main primary coil is shut off, and controls the energization to the sub-switch means. An ignition device for an internal combustion engine, characterized in that the discharge energy generated in the secondary coil is increased in a superimposed manner by performing.
Sub-primary current detection means for detecting a sub-primary current flowing in the sub-primary coil of the ignition 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, and brings the sub primary current detection value closer to the sub primary current target value. Thus, the ignition device for an internal combustion engine according to claim 1, wherein sub-primary current feedback control for controlling electric power supplied to the sub-primary coil is performed.
3. The ignition device for an internal combustion engine according to claim 2, wherein the ignition control means performs sub primary current feedback control by PWM control of the sub switch means.
The ignition control means compares the sub primary current target value and the sub primary current detection value for each predetermined unit period, and controls supply power to the sub primary coil in the next unit period according to the comparison result. The internal combustion engine ignition device according to claim 2 or 3, wherein the ignition device is configured as described above.
A secondary current detecting means for detecting a secondary current flowing in the secondary coil of the ignition coil;
The ignition control means compares the preset secondary current target value with the secondary current detection value detected by the secondary current detection means, and brings the secondary current detection value closer to the secondary current target value. The ignition device for an internal combustion engine according to claim 2, wherein the sub primary current target value is set and changed as described above.
The secondary current target value uses a secondary current target upper limit value predetermined as an upper limit of an allowable secondary current and a secondary current target lower limit value predetermined as a lower limit of an allowable secondary current, The secondary current target upper limit value and the secondary current target lower limit value are compared with the secondary current detection value, and when the secondary current detection value is higher than the secondary current target upper limit value, the secondary current target upper limit value and the secondary current target lower limit value are reduced. The primary current target value is set and changed, and when the secondary current detection value is lower than the secondary current target lower limit value, the sub primary current target value is set and changed to increase the secondary current. Item 6. An ignition device for an internal combustion engine according to Item 5.
Between the primary primary coil of the ignition coil and the main switch means, primary coil voltage detection means for detecting a primary side voltage generated during the discharge of the ignition coil continues,
6. The ignition control unit according to claim 5, wherein the ignition control unit changes the setting so that the secondary current target value is increased when the primary coil voltage rises above a predetermined voltage earlier than a predetermined inclination angle. Item 7. The ignition device for an internal combustion engine according to Item 6.