JP4911177B2 - Ignition device for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition device for an internal combustion engine, and more particularly to an ignition device that causes ignition discharge to occur multiple times within a single combustion stroke.

In order to improve the combustion state of an internal combustion engine, a so-called multiple discharge ignition device has been proposed in which ignition discharge is generated a plurality of times in a spark plug within one combustion stroke.
For example, Patent Document 1 includes an energy storage coil and a first switch unit connected to the energy storage coil. The primary coil of the ignition coil includes an energy storage coil, an ignition start capacitor, and a second A configuration is disclosed in which the switch means is connected and the spark plug is connected to the secondary coil of the ignition coil.

  Then, by alternately turning on and off the first and second switch means, the energy storage coil repeatedly stores and releases energy, and the current whose polarity reverses positively and negatively on the secondary side of the ignition coil. (Hereinafter referred to as discharge current) repeatedly flows, and multiple discharge is performed. In this multiple discharge, each time the absolute value of the discharge current detected by the current detection means is reduced to a predetermined discharge sustaining current, the first and second switch means are switched on / off, thereby allowing a predetermined period of time. The multiple discharge is to be continued (for example, see Patent Document 1).

JP2007-211631 (page 5-8, FIG. 1-2)

  The discharge energy imparted to the fuel gas by the discharge at the spark plug is the time integral value of the product of the discharge current and the spark plug gap voltage, but the fuel compression ratio and the spark plug discharge gap length are kept constant. In this case, the gap voltage during the discharge period is substantially constant, so that the discharge energy is proportional to the absolute value of the integrated value of the discharge current. As described above, the polarity of the discharge current is reversed between positive and negative and multiple discharge is maintained. In order to stabilize the combustion of fuel during the multiple discharge period in the internal combustion engine, it is applied to the fuel gas in the state of positive and negative polarities. The temporal variation of the discharge energy generated must be reduced. That is, it is important to balance the absolute value of the integrated value of the discharge current in each of the positive polarity and negative polarity periods.

  The discharge current has a resonance waveform in which harmonic surge current is superimposed due to resonance of leakage inductance between the ignition start capacitor and the ignition coil. In the conventional ignition device, since only the instantaneous value of the discharge current is observed and the first and second switch means are switched on / off, the absolute value of the discharge current is discharged even for a moment due to the influence of the surge current. When the current is lower than the sustain current, the polarity of the discharge current is reversed, the discharge energy on the positive electrode side and the negative electrode side is significantly asymmetric, and the discharge energy may fluctuate greatly in time. There was a problem that stable combustion could not be realized.

  The present invention has been made to solve the above-described problem, and realizes stable combustion during a multiple discharge period even in a resonance waveform in which a harmonic surge current is superimposed on a secondary side current of an ignition coil. An object of the present invention is to provide an ignition device for an internal combustion engine.

Ignition system for an internal combustion engine according to the present invention, DC and ignition coil spark plug is connected to the secondary side, current detection means for measuring a current flowing through the spark plug, and one end of the primary side of the ignition coil and power energy storage coil provided between a first switch means provided between the one end and the ground, a second switch means connected to the primary side of the ignition coil, it said in a combustion stroke forward period measured current signal by the current detection means becomes a positive polarity and comprising a fly-back period and a negative polarity to appear alternately, and the first switching means on / off control of the second switch means a ignition device for an internal combustion engine and a control means for performing, the control means, the sum of the forward period and the flyback period and period, the current of the flyback period When the absolute value of the integral value of the signal is larger than the absolute value of the integral value of the current signal in the forward period, the flyback period of the next combustion stroke is controlled to be long and the forward period is shortened, When the absolute value of the integral value of the current signal in the flyback period is smaller than the absolute value of the integral value of the current signal in the forward period, the flyback period of the next combustion stroke is shortened and the forward period is Control is made to be long, and the period is controlled to be a fixed value .

  According to the ignition device for an internal combustion engine according to the present invention, the difference between the absolute values of the integral values of the discharge current in the flyback period and the forward period is reduced, that is, the temporal fluctuation of the discharge energy applied to the fuel gas in both periods Since the first and second switch means can be controlled so as to reduce the above, stable combustion can be realized during the multiple discharge period.

1 is a configuration diagram showing an ignition circuit of an internal combustion engine according to Embodiment 1 of the present invention. 3 is a timing chart showing the operation of the ignition circuit of the internal combustion engine according to the first embodiment of the present invention. It is a figure which shows the relationship between the electric current waveform and duty in the ignition circuit of the internal combustion engine by Embodiment 1 of this invention. It is a block diagram which shows the ignition circuit of the internal combustion engine by Embodiment 2 of this invention. It is a block diagram which shows the ignition circuit of the internal combustion engine by Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an ignition device for an internal combustion engine according to Embodiment 1 of the present invention.
In this figure, one end of an energy storage coil 2 is connected to a DC power source 1 such as a battery or a DC / DC converter, and the first switch means 3 is connected to the other end of the energy storage coil 2. ing. The other end of the energy storage coil 2 is further connected to a wire from one end on the primary side of the ignition coil 5 via a diode 4, and an ignition start capacitor is connected to one end on the primary side of the ignition coil 5. The other end of the ignition start capacitor 6 is also connected to the ground. The second switch means 7 is connected to the other end of the primary side of the ignition coil 5. The second switch means 7 is connected between one end of the primary side of the ignition coil 5 and the diode 4. It may be connected in series. Here, IGBT, FET, bipolar transistor or the like can be used for the first switch means 3 and the second switch means 7.

A spark plug 8 is connected to one end of the secondary side of the ignition coil 5, and a current detection means 9 is connected to the other end. Current detecting means 9, the current flowing through the secondary side of the ignition coil 5, i.e. is for detecting the discharge current I ₀ flowing through the spark plug 8, the current detecting resistor and a current detector using a Hall element, A current transformer or the like can be used.

  The control means 10 includes an ignition command signal (Cont1, Cont2), a multiple discharge signal (Cont3) input from an external circuit such as an electronic control unit (ECU) (not shown), and an ignition coil 5 output from the current detection means 9. Based on the discharge current signal on the secondary side, the ON / OFF timing of the first switch means 3 and the second switch means 7 is controlled. The ignition command signal is input to the control means 10 via a plurality of signal lines or one signal line, and includes an ignition preparation signal Cont1 and an ignition period signal Cont2.

  The control means 10 generates an integrator 11 that integrates the current signal input from the current detection means 9, an adjuster 12 that adjusts a value by performing PI control or the like on the integration result, and generates a carrier signal such as a triangular wave. ON / OFF timing of the first switch means 3 and the second switch means 7 in the multiple discharge period by comparing the carrier signal from the carrier signal generator 13 and the carrier signal generator 13 with the signal from the regulator 12 A PWM (Pulse Width Modulation) comparator 14 that generates a signal, and a timing signal generated by the PWM comparator 14 in accordance with the ignition preparation signal Cont1, the ignition period signal Cont2, and the multiple discharge signal Cont3, the first switch means 3 and the second The timing control circuit 15 outputs to the switch means 7.

Next, the basic operation of each part in the circuit shown in FIG. 1 will be described based on the operation sequence of the entire ignition operation shown in FIG.
In this graph, GS1, GS2 is the gate signal for controlling the first switching means 3 and the on / off the second switch means 7, which is generated by the timing control circuit 15, V _C is the ignition start capacitor 6 charging voltage of, I _L is the current flowing through the energy storage coil, I _T1 primary side current of the ignition transformer 5, I ₀ denotes the discharge current, respectively.

It is assumed that the ignition start capacitor 6 is charged with the voltage V _C1 in the initial state (time t1). When the ignition preparation signal Cont1 rises at time t1, GS1 is turned on, but GS2 remains off. Since the voltage of the DC power source 1 is applied to both ends of the energy storage coil 2, the current I _L of the energy storage coil 2 and the energy stored in this current (when the inductance of the energy storage coil is Le, 1 / 2Le · I _L ² ) increases.

At time t2, when the ignition preparation signal Cont1 falls and the ignition period signal Cont2 rises, the first switch means 3 (GS1) is turned off and the second switch means 7 (GS2) is turned on to start ignition. The initial voltage V _{C1 of the} capacitor 4 is applied to the primary side of the ignition coil 5 and at the same time a high voltage is generated on the secondary side. As a result, a high voltage is applied to the spark plug 8 and ignition discharge starts.

For example, if the initial voltage of the ignition start capacitor 6 is V _C1 = 300 V, the primary winding of the ignition coil 5 is Np, the secondary winding is Ns, and the turns ratio Nr = Ns / Np = 100, the ignition coil 5 A voltage of 30 kV can be generated on the secondary side. Actually, a higher voltage of 35 to 40 kV is instantaneously applied to the spark plug 8 due to LC resonance due to the leakage inductance of the ignition coil 5 and stray capacitance. Using this voltage, ignition discharge can be started in the spark plug 8.

Following the discharge from the start of ignition capacitor 6, the current I _L flowing in the energy storage coil 2 to flow in the primary side of the ignition coil 5, the excitation in the case of expressing the ignition coil 5 in transformer equivalent circuit The current I _P is accumulated in the inductance L _P, and the secondary side of the ignition coil 5 has (I _L −I _P ) / Nr (Formula 1)
Current can flow. It is called a forward operation to a operation of accumulating current I _P to the exciting inductance L _P as described above, that the period for the forward operation is called "forward period".

Here, the change of the current I _L flowing through the energy storage coil 2 is expressed by dI _L / dt = V _L / Le, assuming that V _L is applied to both ends thereof, but by sufficiently increasing Le, frequently compared to I _T1 which polarity is reversed, the change of the current I _L can be sufficiently reduced. That is, the circuit including the energy storage coil 2, the first switch means 3, and the diode 4 has a constant current characteristic, and can be regarded as a current source capable of intermittent output.

As described above, since the magnetizing inductance L _P I _P is gradually increased by flowing a current I _L from the energy storage coil 2, as I _L described above which can be regarded as almost constant, according to (Equation 1) it can flow a predetermined discharge current I ₀ which gradually decreases the spark plug 8 connected to the secondary side of the ignition coil 5. Here, a substantially constant voltage (typically about 1 kV) determined by the compression ratio of the fuel and the discharge gap length of the spark plug is applied to the spark plug 8 after starting the discharge.

Energy of the energy storage coil 2 during the period from time t2 to t3 is released, the current I _L of the energy storage coil 2 decreases gradually. Released energy, in addition to being used as a discharge energy in the spark plug 8, is stored as an excitation energy of the excitation inductance L _P of the ignition coil 5, and part of it is consumed by the parasitic resistance component of the circuit.
The timing at time t3 is the time at which the multiple discharge period signal Cont3 rises. This Cont3 may be given from an external circuit such as an ECU, or may be generated by the timing control circuit 15. When generating the timing control circuit 15, the time from time t2 to time t3, may be a predetermined time determined in advance, by measuring the discharge current I _0, the absolute value is lowered to a predetermined value The time may be defined as t3.

At time t3, the first switch means 3 (GS1) is turned on and the second switch means 7 (GS2) is turned off, so that energy is stored in the energy storage coil 2 again. At this time, since the primary current I _T1 of the ignition coil 5 is interrupted, the exciting current I _P flowing in the exciting inductance L _p of the ignition coil 5 is output from the secondary winding, the spark plug 8 Is a current I ₀ having a polarity opposite to that of the current flowing during the period from t2 to t3.
Current value, the secondary side converted value of the exciting current at this time, i.e. _{- (I L -I P) /} Nr ( Equation 2)
It is. Here focusing on operation of the ignition coil 5, the period of t3~t4 emits excitation current I _P stored in the exciting inductance L _P of the ignition coil 5, because a period of performing a so-called fly-back operation, "Fly This is referred to as “back period”.

  By turning off the first switch means 3 (GS1) and turning on the second switch means 7 (GS2) at time t4, the same operation as the forward operation in the period from time t2 to t3 is performed at time t4 to t5. Done. However, since the ignition start capacitor 6 has already been discharged, unlike the period from t2 to t3, the operation of applying a high voltage to the spark plug 8 is not performed. By turning on the first switch means 3 (GS1) and turning off the second switch means 7 (GS2) at time t5, the same operation as the flyback operation in the period from time t3 to t4 at time t5 to t6. Is done. The same applies to after time t6.

As described above, the multiple discharge period is the discharge current I ₀ whose polarity is reversed to the secondary side of the ignition coil 5 by alternately turning on / off the first switch means 3 and the second switch means 7. Is a period during which the discharge energy is supplied to the spark plug 8. However, as described above, during the period from t2 to t3 immediately after the start of discharge, the waveform of _I0 is different from other forward sections due to the influence of the discharge of the ignition start capacitor 6, so this portion is excluded. In FIG. The section up to t9 is called a multiple discharge period, and the multiple discharge signal Cont3 is in the ON state during this period.

During the time period from t9 to t10, current _{I L} of the energy storage coil 2 is increased energy is stored. The timing of time t10 is a time at which the ignition period signal Cont2 falls, to the time of the time t9~t10 may be preliminarily predetermined time determined, by detecting the current I _L flowing through the energy storage coil 2 it may be determined the time when I _L falls to a predetermined value as t10.

At time t10, energy storage in the energy storage coil 2 is completed, and both the first switch means 3 (GS1) and the second switch means 7 (GS2) are turned off. Then, the energy stored in the energy storage coil 2 flows into the ignition start capacitor 6 and the ignition start capacitor 6 is charged to the same value (V _C1 ) as the initial voltage, and a series of operations in the combustion stroke is completed.

Next, a control method for reducing the difference between the discharge energy supplied to the spark plug 8 during the flyback period and the discharge energy supplied to the spark plug 8 during the forward period will be described.
During the multiple discharge period, as described above, the discharge current I ₀ whose polarity is inverted between the flyback period and the forward period flows on the secondary side of the ignition coil 5, and discharge energy is supplied to the spark plug 8. As described above, if the fuel compression ratio and the discharge gap length of the spark plug 8 are kept constant, the voltage generated in the spark plug 8 after the start of discharge can be kept constant, and therefore flows during the flyback period. If the difference between the absolute value of the integral value of the positive polarity discharge current and the absolute value of the integral value of the negative polarity discharge current flowing in the forward period can be reduced, the difference in discharge energy in both periods can also be reduced. . As a result, the temporal variation of the discharge energy applied to the fuel gas in both periods can be reduced, and stable combustion can be realized during the multiple discharge period.

Therefore, first, the current detection means 9 measures the discharge current I ₀ flowing through the spark plug 8 during the multiple discharge period.
The current signal is sent to the integrator 11 and is integrated only during the period when the multi-period signal Cont3 is on. Since the currents in the flyback period and the forward period have opposite polarities, the difference between the absolute values of the current integrated values in both periods can be obtained by this integration. The integrator 11 may be a combination of an integration circuit constituted by an operational amplifier and a hold circuit, or a logic circuit or a microprocessor that adds a current signal only while the Cont3 signal is on. it can.

Based on the difference in absolute value of the current integral value in each period of the flyback period and forward period obtained in a certain combustion stroke, the difference in absolute value of the current integral value in the next combustion stroke is greater than that in the previous combustion stroke. The control means 10 is configured as a feedback control system so that each timing of the flyback period and the forward period can be determined so as to be reduced.
The integration result by the integrator 11 is sent to the adjuster 12. In the adjuster 12, the difference between the absolute values of the current integral values stably converges as the feedback control system undergoes a plurality of combustion strokes. As described above, the control system type (proportional [P] / integral [I] / derivative [D]) is selected or combined, and each control constant (gain, time constant) in this control system is appropriately determined. It is done.

  The output signal from the regulator 12 is compared with the carrier signal output from the carrier signal generator 13 in the PWM comparator 14, and the first switch means 3 and the second switch means 7 are turned on / off during the multiple discharge period. Is determined. How to determine the timing will be described below.

FIG. 3 shows the relationship between the magnitude of the discharge current I ₀ and the lengths of the flyback period and the forward period. Here, when the flyback period one cycle time T _B and the forward period batch of time was T _F, the period T defined by T = T B ₊ T _F a fixed value it. Further, the duty D is defined as D = _TF / T.
For example, as shown in (b) of FIG. 3, when obtained by multiple discharge at D = 50%, the sum of the absolute value of the current integral of the absolute value of the sum and the period T _F of current integral period T _B Suppose they were equal. From this condition, increase the length of the T _F as in FIG. 3 (a), i.e. increasing the duty D, more current flows from the energy storage coil 2 in the period T _F in the exciting inductance L _P, the ignition coil 5 since the energy stored in increases, the peak value of the current I ₀ of the next period T _B increases. On the other hand, minute T _B where T _F is prolonged for the period T is fixed shorter, since also small amount of current decreases in the ignition coil 5 during which the peak value of the current I ₀ in the next period T _F Becomes smaller.

As shown in FIG. 3C, when the length of _TF is shortened, that is, when the duty D is decreased, the opposite result is obtained.
That is, it has been found that when it is desired to increase the discharge energy (energy in the forward period) due to the negative polarity current I ₀ , the duty (ratio of the forward period) must be decreased rather than increased.

Based on the above knowledge, in the present invention, the flyback period and the forward period are controlled as follows.
For example, when the absolute value of the current integral value in the forward period is larger than the absolute value of the current integral value in the flyback period, that is, when the output from the integrator 11 is negative, both integrals are performed in the next combustion stroke. The duty is increased so that the difference between the values becomes smaller, and the timing is set so that the forward period becomes longer.
Conversely, when the absolute value of the current integral value in the forward period is smaller than the absolute value of the current integral value in the flyback period, that is, when the output from the integrator 11 is positive, both integrals are performed in the next combustion stroke. The timing is set so that the duty is decreased so that the difference between the values becomes smaller and the forward period becomes shorter.

  In the timing control circuit 15, on / off of the first switch means 3 and the second switch means 7 in the whole period based on the ignition command signals (Cont 1, Cont 2), the multiple discharge signal Cont 3, and the output of the PWM comparator 14. And the gate signals GS1 and GS2 are sent to each switch.

By defining the flyback period and the forward period according to the procedure described above, the difference between the absolute values of the current integral values in both periods can be converged to a small value by repeating the combustion stroke. Both periods have not been optimized. Therefore, by first setting the duty to 50%, the difference between the absolute values of the current integrated values in both periods can be made relatively small.
Alternatively, duty information at the time of engine operation or immediately before stopping is recorded in an external circuit such as a non-volatile memory provided in the control circuit 10 or an electronic control unit (ECU), the engine is stopped once, and then the engine is started again. In this case, the recorded duty may be read and used as an initial value. By setting the initial value of the duty in this way, combustion can be stabilized immediately after the engine is started.

  As described above, based on the difference between the absolute values of the current integration values in the flyback period and the forward period for the secondary side current of the ignition coil 5, the first current is set so that this difference is reduced in the next combustion stroke. By controlling the timing of the switch means 3 and the second switch means 7, the temporal variation of the discharge energy applied to the fuel gas in both periods can be reduced, and stable combustion can be realized during the multiple discharge periods. Can do.

Embodiment 2. FIG.
FIG. 4 shows the configuration of an ignition device for an internal combustion engine according to Embodiment 2 of the present invention. The difference from the first embodiment is that the control means 16 is provided with a polarity separation circuit 17 to separate the current signal input from the current detection means 9 into positive polarity and negative polarity, and the integrator 18 is positive polarity (flying). 2 circuits, one for negative period (forward period) and one for negative polarity (forward period), and two outputs from this integrator 18 are input, and the absolute value of the current integrated value in the flyback period and forward period is A comparator 19 for obtaining a difference is provided, and the regulator 20 determines each control constant using not only the difference between the absolute values of the current integrated values but also the current integrated values themselves.
Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

  According to the present embodiment, it is possible to grasp the ratio of the difference between the absolute values of the integral values of both periods with respect to the integral values of the flyback period and the forward period, and based on this, the regulator 20 can determine the control constant more appropriately. Therefore, in addition to achieving the same effect as the first embodiment, there is an effect that the convergence stability of the control system can be increased or the convergence speed can be increased as compared with the first embodiment.

Embodiment 3 FIG.
In a multiple discharge type ignition device in which an ignition discharge is generated multiple times in a single combustion stroke, there is a problem in that ignition does not occur or ignition does not continue stably if the total discharge energy is too small. On the other hand, if it is too large, the discharge energy is wasted and the damage to the spark plug is increased, so that there is an optimum value for the discharge energy.
In a combustion test of an engine equipped with an ignition device, the combustion state in the combustion chamber is observed while changing the length of the multiple discharge period with respect to the engine speed and the amount of accelerator operation, and the minimum combustion state can be ensured. The optimum value of the discharge energy can be obtained by experimentally determining the discharge energy.

  Therefore, in the third embodiment, the value of the optimum discharge energy corresponding to the engine speed and the accelerator operation amount is recorded in advance in an external circuit such as an electronic control unit (ECU), and the actual engine speed. Based on the amount of accelerator operation, the length of the multiple discharge period is adjusted so that the discharge energy becomes an optimum value.

  FIG. 5 shows the configuration of an ignition device for an internal combustion engine according to Embodiment 3 of the present invention. The difference from the second embodiment is that the control means 21 is provided with an adder 22 for obtaining the sum of absolute values of current integration values in the flyback period and the forward period, and is multiplexed based on the optimum discharge energy value obtained by the ECU 23. A multiple discharge period control circuit 24 for determining the discharge period is provided.

  Next, the operation will be described. In the control means 21, the current signal separated into the positive polarity and the negative polarity by the polarity separation circuit 17 is integrated by two types of circuits, one for the positive polarity and one for the negative polarity provided in the integrator 18, The steps up to the determination of the flyback period and the forward period in the next combustion stroke based on the difference between the absolute values of both integral values and the integral values themselves are the same as in the second embodiment. Thus, if the combustion stroke is repeated, the difference between the absolute values of the current integration values in the flyback period and the forward period can be converged to a small value.

  In the present embodiment, the sum of absolute values of both integral values is also obtained by the adder 22. The ECU 23 receives the engine speed and the accelerator operation amount at time t10 when one cycle (t1 to t10) of the combustion stroke of the engine is completed. Since the ECU 23 is equipped with a database of optimum discharge energy values for the engine speed and the accelerator operation amount obtained by the above-described experiment, the ECU 23 is used to calculate the optimum discharge energy value, that is, the sum of the absolute values of the current integrated values. An optimum value (hereinafter referred to as an optimum current integration value) is obtained and sent to the multiple discharge period control circuit 24.

  Until the next combustion stroke starts, the multiple discharge period control circuit 24 calculates the optimum current integrated value input from the ECU 23 and the sum of the absolute values of the current integrated values in the previous combustion stroke input from the adder 22. The lengths of the multiple discharge signals are adjusted so that the latter value is close to the former value. For example, when the signal input from the adder 22 is smaller than the optimum current integrated value input from the ECU 23, it means that the number of multiple discharges is insufficient. The multiple discharge signal Cont3 is changed so as to lengthen the multiple discharge period. On the contrary, when the signal input from the adder 22 is larger than the optimum current integration value input from the ECU 23, it means that the number of multiple discharges is excessive. The multiple discharge signal Cont3 is changed so as to shorten the multiple discharge period.

  As described above, according to the present embodiment, in addition to the same effects as those shown in the first and second embodiments, optimum discharge energy corresponding to the engine speed and the accelerator operation amount can be supplied to the spark plug. Therefore, the power consumption in the ignition circuit can be reduced, and at the same time, the spark plug can be prevented from being worn.

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Energy storage coil 3 1st switch means 5 Ignition coil 7 2nd switch means 8 Spark plug 9 Current detection means 10 Control means 16 Control means 17 Polarity separation circuit 18 Integrator 19 Comparator 21 Control means

Claims (3)

An ignition coil having a spark plug connected to the secondary side;
Current detecting means for measuring a current flowing through the spark plug;
An energy storage coil provided between one end of the primary side of the ignition coil and a DC power source;
First switch means provided between the one end and the ground;
Second switch means connected to the primary side of the ignition coil;
The first switch means and the second switch means are turned on so that the flyback period in which the current signal measured by the current detection means in the combustion stroke is positive and the forward period in which the current signal is negative appear alternately. An ignition device for an internal combustion engine comprising control means for performing off / off control,
The control means includes
The cycle is the sum of the flyback period and the forward period,
When the absolute value of the integral value of the current signal in the flyback period is larger than the absolute value of the integral value of the current signal in the forward period, the flyback period of the next combustion stroke is lengthened and the forward period is increased. Control to shorten,
When the absolute value of the integral value of the current signal in the flyback period is smaller than the absolute value of the integral value of the current signal in the forward period, the flyback period of the next combustion stroke is shortened and the forward period is Control to be longer,
An ignition device for an internal combustion engine, wherein the cycle is controlled to be a fixed value . The control means
A polarity separation circuit for separating the current signal in the flyback period and the current signal in the forward period;
An integrator for calculating each integral value in the flyback period and the forward period for the current signal;
A comparator for obtaining a difference between absolute values of the integrated values;
A timing control circuit for determining a flyback period and a forward period in the next combustion stroke based on each integral value and the difference;
Ignition system for an internal combustion engine according to claim 1, characterized in that with a. The control means
From the difference between the sum of the integral values of the current signals in the multiple discharge period and the optimum current integral value, the sum of the integral values of the current signals in the multiple discharge period of the next combustion stroke and the optimum current integral value The ignition device for an internal combustion engine according to claim 2 , wherein the multiple discharge period of the next combustion stroke is determined so that the difference between the two is smaller .

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