JP2001012288A - Ignition control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Problem] After returning to normal from a cylinder discrimination abnormality, without energizing the back-up to the intake system, the energization of the cylinder that is kept energized is immediately cut off, and two cylinders are simultaneously energized. While energization is avoided, ignition control is restarted immediately. SOLUTION: When a cylinder discrimination NG is diagnosed, the ignition control is stopped, and the energized state is maintained for the cylinder (# 3) whose energization to the ignition coil was started immediately before the NG diagnosis. After returning to the cylinder determination OK, energization of the energized holding cylinder (# 3) is cut off at the ignition timing of the back cylinder (# 6) having a crank angle different from that of the cylinder by 360 °. At this time, the intake valve opening timing is delayed so that the intake valve of the cylinder (# 3) whose energization is cut off does not start to open.
Thereafter, the cylinder (# 1) which is the normal energization start timing
Restarts the ignition control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs cylinder discrimination,
The present invention relates to an ignition control device for an internal combustion engine which controls ignition by controlling the start and stop of energization to an ignition coil of each cylinder in accordance with the cylinder discrimination result.

[0002]

2. Description of the Related Art In a conventional ignition control apparatus for an internal combustion engine, cylinder discrimination is performed based on a signal from a cylinder discrimination sensor mounted on a camshaft, and energization of an ignition coil of each cylinder is started and energized in accordance with the cylinder discrimination result. Although the shutoff is controlled to control the ignition, if the noise from the signal from the cylinder discrimination sensor occurs, the cylinder discrimination may be erroneously made and erroneous power distribution may occur.

Therefore, every time the cylinder discrimination is performed, the latest cylinder discrimination value is compared with the cylinder discrimination estimated value estimated from the previous cylinder discrimination value. Diagnosis of abnormality.

[0004] When it is determined that the cylinder discrimination is abnormal, the ignition control is temporarily prohibited until it is determined that the cylinder is normal. Therefore, the cylinder (final passing electric cylinder) that has been energized to the ignition coil immediately before the cylinder discrimination abnormality is diagnosed is kept in the energized state. If the ignition is interrupted with the power supply turned off, unexpected problems such as damage to the air flow meter due to backfire on the intake system will occur.Therefore, wait until the normal ignition timing of the cylinder that is maintained in the energized state is reached, and then The energization is shut off (see Japanese Patent Application Laid-Open No. 6-2641).

[0005]

However, such a conventional ignition control device has the following problems.

Immediately after the cylinder discrimination returns to normal, immediately after energization is started in accordance with the original ignition order, two cylinders including the cylinders which are kept energized are energized simultaneously, resulting in a large increase in current. And the fuse of the ignition power system is blown (see Conventional Example 1 in FIG. 9A).

Further, in order to avoid simultaneous energization of the two cylinders, after the energization of the cylinder being energized is interrupted at the normal ignition timing, the ignition control is restarted from the cylinder at the normal energization start timing. Then, there is a problem that ignition cannot be performed during two revolutions, and engine stall due to missing ignition easily occurs (see Conventional Example 2 in FIG. 9B).

In any case, the last electric cylinder immediately before the cylinder discrimination abnormality is diagnosed remains energized for two rotations, which may lead to burning of the ignition coil. The present invention has been made in view of such a conventional problem, and after returning to a normal state from a cylinder discrimination abnormality, the energization of a cylinder which is maintained in an energized state relatively quickly without causing backfire to the intake system. Disclosed is an ignition control device for an internal combustion engine that can minimize the energization holding time as much as possible, and can avoid simultaneous energization of two cylinders, and can restart ignition control relatively quickly without stalling. With the goal.

[0009]

Therefore, in the invention according to the first aspect, as shown in FIG. 1, cylinder discrimination is performed by cylinder discriminating means, and energization of the ignition coil of each cylinder is started in accordance with the cylinder discrimination result. And an ignition control device for an internal combustion engine that controls ignition by controlling power supply interruption and a diagnosis unit that diagnoses whether or not the cylinder determination by the cylinder determination unit is normal or abnormal.
When the cylinder discrimination abnormality is diagnosed, the ignition control is stopped, and the ignition control stopping means for maintaining the energized state for the cylinder which has started energizing the ignition coil immediately before the abnormality is diagnosed, and the cylinder discrimination is normal. After returning to, the cylinder maintained in the energized state has a crank angle of 36
Fail-safe energization interrupting means for interrupting energization to the ignition coil at an ignition timing of the back cylinder having a phase difference of 0 °;
When the energization is interrupted at the ignition timing of the back cylinder,
An intake valve opening timing delay means for delaying the intake valve opening timing so that the intake valve of the cylinder whose energization is cut off does not start to open is provided.

The invention according to claim 2 is characterized in that an ignition control restarting means is provided for restarting ignition control from a cylinder at a regular energization start timing after energization is cut off at the ignition timing of the back cylinder. .

In the invention according to claim 3, the diagnosis means compares the latest cylinder discriminating value with the cylinder discriminating estimated value estimated from the previous cylinder discriminating value, and determines whether the two cylinders match or not. It is characterized by diagnosing normal / abnormal judgment.

[0012]

According to the first aspect of the invention, when the cylinder discrimination abnormality is diagnosed, the ignition control is stopped, and the energized state is maintained for the last electric cylinder immediately before the abnormality is diagnosed, After the cylinder discrimination has returned to normal, the cylinder maintained in the energized state has a crank angle of 36
At the ignition timing of the back cylinder having a different phase of 0 °, that is, at the latter stage of the exhaust stroke, the power supply to the ignition coil is cut off,
At this time, the opening timing of the intake valve is delayed so that the intake valve of the cylinder whose energization is cut off does not start to open, so that the energized state is maintained relatively quickly without causing backfire to the intake system. Cut off the energized cylinder,
The power supply holding time can be shortened as much as possible, and the ignition control can be restarted relatively quickly without fear of engine stall even after restarting the ignition control in order to avoid simultaneous energization of the two cylinders.

According to the second aspect of the invention, after the energization is interrupted at the ignition timing of the back cylinder, the ignition control is restarted from the cylinder at the normal energization start timing.
Simultaneous energization of the cylinders can be reliably prevented.

According to the third aspect of the present invention, it is possible to accurately diagnose whether the cylinder is normal or abnormal.

[0015]

Embodiments of the present invention will be described below. Here, a six-cylinder engine is taken as an example, and the cylinder numbers (# 1 to # 6) are in the ignition order.

FIG. 2 is a system diagram of an embodiment of the present invention. The ignition plug 1 of each cylinder includes a corresponding ignition coil 2. The ignition coil 2 for each cylinder is driven by the control unit 3 via the driver 4, is energized at a predetermined energization start timing, is deenergized at a predetermined ignition timing, and outputs a high voltage when the energization is interrupted. 1 so that ignition by the spark plug 1 is performed.

The control unit 3 receives signals from the cylinder discriminating sensor 5 and the crank angle sensor 8. The cylinder discriminating sensor 5 outputs one for every two rotations of the crankshaft.
Protrusions are provided on the signal disk plate 7 attached to the rotating camshaft 6 every 60 ° (every 120 ° of crank angle), and the number of each protrusion is different from 1, 4, 5, 2, 3, 6 In advance, the projection of the signal disk plate 7 is detected, and a cylinder discrimination signal Phase having a different number of pulses is output for each cylinder that can be discriminated. The number of projections is made different in consideration of the rotational balance.

The crank angle sensor 8 has a signal disk plate 10 attached to the crankshaft 9 for example,
A projection is provided for each unit crank angle of 0 °, and a reference crank angle position for each 120 ° (for example, 20 cylinders after TDC of each cylinder).
°), the protrusion of the signal disk plate 10 is detected, and the unit crank angle signal POS is detected.
Is output.

The position of the first projection of each projection group of the signal disc plate 7 of the cylinder discriminating sensor 5 is made to correspond to the reference crank angle position of the signal disc plate 10 of the crank angle sensor 8 (the position from which the projection is removed), Thereby, the reference crank angle position can be detected. Therefore, by counting the number of generations of the unit crank angle signal POS after detecting the reference crank angle position,
The crank angle position can be detected. When the unit crank angle is set to 10 °, the crank angle position is specified by a known time control during that time.

Inputs to the control unit 3 include an air flow meter for detecting an intake air amount, an accelerator pedal sensor for detecting an accelerator opening, a throttle for detecting a throttle opening, in addition to a cylinder discrimination sensor 5 and a crank angle sensor 8. Although there is a signal from a sensor or the like, illustration is omitted.

The control device based on the output of the control unit 3 includes, in addition to the ignition coil 2 of each cylinder, a fuel injection valve, an electronically controlled throttle valve, and a variable valve operating device for the intake and exhaust valves of each cylinder. Only the variable valve train 11 is shown.

The variable valve operating device 11 only needs to be able to control at least the opening / closing timing (particularly the opening timing) of the intake valve, and may change the phase of a cam shaft for driving the intake valve, for example. Alternatively, an electromagnetic valve device that drives the intake valve with an electromagnetic actuator may be used.

Next, referring to the time chart of FIG.
The ignition control according to the present invention will be described with reference to the flowcharts of FIGS. FIG. 4 shows a routine executed at a timing of 20 ° before TDC of each cylinder.

In step 1 (referred to as S1 in the figure, the same applies hereinafter), the next estimated cylinder determination value CYLGATE = CYLCS + 1 is obtained from the current cylinder determination value CYLCS. However, when CYLCS = 6, CYLGATE =
Let it be 1. For example, at the timing of a in FIG.
Since S = 1, CYLGATE = 2.

FIG. 5 shows a routine executed at a timing of 10 ° before TDC of each cylinder. In step 11, the value of the cylinder discrimination counter C which counts the number of pulses of the cylinder discrimination signal Phase output after the reference crank angle position of 20 ° after TDC of each cylinder is read. At timing b in FIG. 3, C = 1 is read.

In step 12, based on the value of the cylinder discrimination counter C, cylinder discrimination is performed as follows, and the cylinder discrimination value CYLCS is updated. C = 1 (pulse number 1) → CYLCS = 2 (# 2 cylinder) C = 4 (pulse number 4) → CYLCS = 3 (# 3 cylinder) C = 5 (pulse number 5) → CYLCS = 4 (# 4 cylinder) ) C = 2 (number of pulses 2) → CYLCS = 5 (# 5 cylinder) C = 3 (number of pulses 3) → CYLCS = 6 (# 6 cylinder) C = 6 (number of pulses 6) → CYLCS = 1 (# 1 (Cylinder) At the timing b in FIG. 3, C = 1, so CYL
CS = 2.

In step 13, the cylinder discrimination value CYLCS and the cylinder discrimination estimated value CYLGA are used to diagnose the cylinder discrimination.
Compare with TE. If CYLCS = CYLGATE, the process proceeds to step 14, where the cylinder determination is OK (normal).

At timing b in FIG. 3, CYLCS =
2. Since CYLGATE = 2, CYLCS = CY
LGATE, and the cylinder determination is OK. Then, in step 15, the value of the energized holding cylinder stored value CYLFDW is checked, and if CYLFDW = 0 (no energized holding cylinder), this routine ends.

FIG. 6 shows a routine executed at a timing of 10 ° after TDC of each cylinder. In step 31, it is determined whether the cylinder determination is OK or NG. In the case of cylinder determination OK,
For example, in the case of the timing c in FIG. 3, the process proceeds to step 32, and the ignition counter of the cylinder (# 2) corresponding to the cylinder discrimination value CYLCS which has already been energized is started.

Next, at step 33, the value of the energized holding cylinder stored value CYLFDW is checked, and if CYLFDW = 0 (no energized holding cylinder), the routine proceeds to step 34, where the next cylinder of the cylinder corresponding to the cylinder discrimination value CYLCS is determined. The energization start counter for the cylinder (cylinder corresponding to the cylinder discrimination value CYLCS + 1; # 3) is started, and this routine ends.

FIG. 7 shows a routine executed when the ignition timing is detected based on the ignition counter. In step 41, the cylinder is ignited by cutting off the current to the ignition coil of the cylinder corresponding to the cylinder discrimination value CYLCS (for example, the # 2 cylinder is ignited at the timing of d in FIG. 3).

In step 42, the value of the failsafe flag is determined, and if = 0, this routine ends.
FIG. 8 is a routine executed when the energization start timing is detected based on the energization start counter.

In step 51, the cylinder discrimination value CYLCS
(Cylinder determination value CYLCS + 1)
To the ignition coil of the cylinder corresponding to (# 1) (for example, at the timing of e in FIG. 3, the energization of the # 3 cylinder is started).

Next, a case where an abnormality has occurred in the cylinder discrimination will be described. For example, as shown in FIG. 3, this is a case in which noise is superimposed on the cylinder discrimination signal Phase having four pulses and the pulse number becomes five.

In this case, FIG.
At the timing of middle f, the routine of FIG.
YLGATE = 3, but at the timing of g in FIG. 3 at 10 ° before TDC of each cylinder, CYLCS = 4 (erroneous) due to the routine of FIG.
CS ≠ CYLGATE.

In this case, in the routine of FIG. 5, CYLCS ≠ CYLGATE is obtained in the determination at step 13, so the routine proceeds to step 16, where the cylinder determination is NG (abnormal).

Then, in step 17, the value of the energized holding cylinder stored value CYLFDW is checked, and CYLFDW =
If it is 0, the processing of steps 18 to 20 is performed. In step 18, in order to store the cylinder number of the cylinder that has been energized immediately before the cylinder discrimination NG has been diagnosed (last electric cylinder), the energized holding cylinder storage value CYLFDW = CYLGAT
E. At timing g in FIG. 3, CYLGATE
= 3, so CYLFDW = 3.

In step 19, the final electric cylinder (CYL)
FDW). In this case, the # 3 cylinder is kept energized. In step 20, the opening timing of the intake valve is delayed by the variable valve operating device to eliminate the overlap with the exhaust valve.

In this case, 10 ° after TDC of each cylinder in FIG.
At the timing of the middle h, in the routine of FIG. 6, the determination in step 31 is the cylinder determination NG, so this routine is terminated as it is. Therefore, neither the ignition counter of CYLCS nor the energization start counter of CYLCS + 1 is started, and the ignition timing and the energization start timing are not reached. Therefore, the ignition of CYLCS (# 3 cylinder) and the CYL are not performed.
The energization of CS + 1 (# 4 cylinder) is not started.

Next, i in FIG. 3 at 20 ° before TDC of each cylinder.
At the timing of CYL, the routine of FIG.
GATE = 5 (erroneous), and at the timing j in FIG. 3 at 10 ° before TDC of each cylinder, CYLCS = 4 by the routine of FIG. 5, so that CYLCS ≠ C
YLGATE.

In this case, in the routine of FIG. 5, CYLCS ≠ CYLGATE is determined in step 13, so that the routine proceeds to step 16, where the cylinder determination is NG. Then, in step 17, the energized holding cylinder stored value CYLF
Check the value of DW. In this case, CYLFDW = 3
Therefore, this routine is terminated as it is.

In this case, 10 ° after TDC of each cylinder in FIG.
At the timing of the middle k, in the routine of FIG. 6, the determination in step 31 is the cylinder determination NG, so this routine is ended as it is. Accordingly, neither the ignition counter of CYLCS nor the energization start counter of CYSCL + 1 is started, and the ignition timing or the energization start timing does not come. Therefore, the ignition of CYLCS (# 4 cylinder) and the CYL are not performed.
The energization of CS + 1 (# 5 cylinder) is not started.

Next, m in FIG. 3 at 20 ° before TDC of each cylinder.
At the timing of CYL, the routine of FIG.
GATE = 5, and at the timing of n in FIG. 3 at 10 ° before TDC of each cylinder, CY is determined by the routine of FIG.
Since LCS = 5, CYLCS = CYLGATE.

In this case, in the routine of FIG. 5, since CYLCS = CYLGATE in the determination at step 13, the routine proceeds to step 14, where the cylinder determination is OK. In step 15, the energized holding cylinder stored value CYLF
The value of DW is checked to determine whether CYLFDW = 0.

In this case, since CYLFDW = 3, the process proceeds to step 21. In step 21, CYLC
S (regular ignition cylinder) is CYLFDW (cylinder holding current)
In contrast, it is determined whether or not the back cylinder has a phase different by 360 ° in crank angle.

When CYLFDW = 3, CYLCS = 6
Is a back cylinder, and at timing n in FIG.
Since S = 5, this routine ends. in this case,
At the timing of o in FIG. 3 at 10 ° after the TDC of each cylinder, the cylinder discrimination is OK in the routine of FIG.
The ignition counter of S (# 5 cylinder) is started.

Also, in the determination at step 33, CYL
Since FDW ≠ 0 (CYLFDW = 3), this routine ends. Therefore, CYLCS + 1 (# 6
The energization start counter for the cylinder does not start.

Therefore, at timing p in FIG. 3, the ignition timing is reached, and the power supply to the ignition coil of the CYLCS (# 5 cylinder) is cut off in step 41 of the routine of FIG. 7, but the power supply is started. Because there is no, CYLCS
(# 5 cylinder) is not ignited. In step 42 of the routine of FIG. 7, it is determined whether or not the fail-safe flag = 1. If the fail-safe flag = 0, the routine is terminated.

Since the energization start counter has not been started and the energization start timing is not reached, FIG.
Is not started and CYLCS + 1 (# 6 cylinder)
Is not started.

Next, at 20 ° before TDC of each cylinder, q in FIG.
At the timing of CYL, the routine of FIG.
GATE = 6, and at the timing of r in FIG. 3 at 10 ° before TDC of each cylinder, CY is determined by the routine of FIG.
Since LCS = 6, CYLCS = CYLGATE.

In this case, in the routine shown in FIG. 5, since CYLCS = CYLGATE in the determination at step 13, the routine proceeds to step 14, where the cylinder determination is OK. In step 15, the energized holding cylinder stored value CYLF
The value of DW is checked to determine whether CYLFDW = 0.

In this case, since CYLFDW = 3, the process proceeds to step 21. In step 21, CYLC
S (regular ignition cylinder) is CYLFDW (cylinder holding current)
It is determined whether or not the back cylinder has a phase different by 360 ° in crank angle.

When CYLFDW = 3, CYLCS = 6
Is the back cylinder, and at the timing r in FIG.
Since S = 6 and the back cylinder, steps 22 and 23
Proceed to.

In step 22, the energized holding cylinder stored value C
Return YLFDW = 0. In step 23, the failsafe flag is set to 1 and the routine ends.

In this case, FIG.
At the timing of the middle s, in the routine of FIG. 6, the determination in step 31 is the cylinder determination OK, so the process proceeds to step 32, and the ignition counter of CYLCS (# 6 cylinder) is started.

In the determination in step 33, CYLF
Since DW = 0, the process proceeds to step 34, where CYLC
The energization start counter for S + 1 (# 1 cylinder) is started. Accordingly, the ignition timing is reached at the timing t in FIG. 3, and the CYL is performed in step 41 of the routine in FIG.
Power supply to the ignition coil of CS (# 6 cylinder) is cut off, but since power supply has not been started, there is no ignition.

In step 42 of the routine of FIG. 7, it is determined whether or not the fail-safe flag = 1. Since the fail-safe flag = 1, the processing of steps 43 to 45 is performed.

In step 43, the energization to the ignition coil of the back cylinder (# 3) of CYLCS (# 6, which is a regular ignition cylinder) is cut off to ignite. Thus, the energization of the last electric cylinder that has been maintained in the energized state can be terminated. At this time, since the # 3 cylinder is in the latter half of the exhaust stroke, the opening timing of the intake valve is delayed to eliminate the overlap with the exhaust valve, so that even if ignition is performed, backfire to the intake system is prevented. Can be.

In step 44, the fail-safe flag is returned to "0". In step 45, the retard of the intake valve opening timing is released by the variable valve operating device, and the present routine ends.

Further, at the timing of u in FIG. 3, the energization start timing is reached, and according to the routine of FIG.
Energization to the +1 (# 1 cylinder) ignition coil is started.
After that, it goes without saying that normal ignition control is performed sequentially from the # 1 cylinder.

The step 12 in FIG. 5 corresponds to the cylinder discriminating means, and steps 11, 13, 14, 16 in FIG.
Corresponds to the diagnostic means. Step 1 in FIG.
8 and 19 correspond to the ignition control stopping means, and correspond to steps 15, 21 to 23 in FIG. 5 and steps 42 and 43 in FIG.
5 corresponds to the fail-safe energizing cutoff means, and the step 20 in FIG. 5 corresponds to the intake valve opening timing delaying means. The steps 31 and 32 in FIG. 6 correspond to ignition control restarting means.

FIG. 9 shows a comparison between Conventional Examples 1 and 2 and the present invention. In the case of Conventional Example 1 shown in FIG. 9A, after the cylinder discrimination returns to the normal state, #
Since the energization is started in the order of 6 → # 1 → # 2 cylinders, two cylinders including the # 3 cylinder, which is maintained in the energized state, are energized at the same time. There are problems such as a fuse being blown.

In the case of Conventional Example 2 shown in FIG. 9B, in order to avoid simultaneous energization of the two cylinders, the energization of the cylinder # 3, which is maintained in the energized state, is cut off at the regular ignition timing, and then the normal Since the ignition control is restarted from the # 4 cylinder, which is the power supply start timing, ignition cannot be performed for two revolutions, and there is a problem that an engine stall due to missing ignition easily occurs.

In each of the conventional examples 1 and 2,
The # 3 cylinder remains energized for two rotations, which may cause ignition coil burnout. In contrast,
In the case of the present invention shown in FIG. 9 (c), for the # 3 cylinder which is kept energized after the cylinder discrimination has returned to normal,
At the ignition timing of the back cylinder (# 6) having a phase different from that of the cylinder by 360 ° in the crank angle, that is, in the latter half of the exhaust stroke,
The current supply to the ignition coil is cut off, and at this time, #
Since the opening timing of the intake valves is delayed so that the intake valves of the three cylinders do not start to open, the energization of the # 3 cylinder, which is maintained in an energized state relatively quickly, without causing backfire to the intake system. , And the current holding time can be shortened as much as possible. Thereafter, by restarting the ignition control from the # 1 cylinder, which is the normal energization start timing, ignition control can be restarted relatively quickly without stalling, and simultaneous energization of the two cylinders can be reliably prevented. .

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is a time chart of ignition control.

FIG. 4 is a flowchart of a 20 ° pre-TDC routine;

FIG. 5 is a flowchart of a 10 ° pre-TDC routine;

FIG. 6 is a flowchart of a 10 ° routine after TDC.

FIG. 7 is a flowchart of an ignition timing routine.

FIG. 8 is a flowchart of an energization start timing routine.

FIG. 9 is a diagram showing a comparison between Conventional Examples 1 and 2 and the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spark plug 2 Ignition coil 3 Control unit 5 Cylinder discrimination sensor 6 Camshaft 8 Crank angle sensor 9 Crankshaft 11 Variable valve gear

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02P 3/04 303 F02P 3/04 303G 5/15 5/15 L F-term (Reference) 3G019 AA05 AB01 AB05 CA02 CA06 CA11 DC06 GA00 GA01 GA02 GA08 GA09 3G022 AA00 AA03 EA08 GA00 GA01 GA02 GA06 GA08 3G084 AA03 BA16 BA23 DA20 DA26 DA27 FA07 FA10 FA35 FA38

Claims (3)

[Claims] 1. An ignition control device for an internal combustion engine for performing cylinder discrimination by cylinder discrimination means and controlling ignition by controlling the start and stop of energization to an ignition coil of each cylinder in accordance with a result of the cylinder discrimination. Diagnosing means for diagnosing normal / abnormal cylinder discrimination by the discriminating means; and for a cylinder which, when diagnosed as abnormal cylinder discrimination, stops ignition control and starts energizing the ignition coil immediately before being diagnosed as abnormal. An ignition control stopping means for maintaining the energized state, and ignition of the cylinder maintained in the energized state after the cylinder discrimination has returned to normal, with the ignition timing of the back cylinder having a phase difference of 360 ° in crank angle with respect to that cylinder. Fail-safe energization shutoff means for interrupting energization to the coil, and when energization is interrupted at the ignition timing of the back cylinder,
An ignition control device for an internal combustion engine, comprising: intake valve opening timing delay means for delaying the opening timing of an intake valve so that the intake valve of a cylinder whose energization is cut off does not start to open. 2. An internal combustion engine according to claim 1, further comprising an ignition control restarting means for restarting ignition control from a cylinder having a regular energization start timing after the energization is interrupted at the ignition timing of said back cylinder. Engine ignition control device. 3. The diagnostic means compares the latest cylinder discrimination value with an estimated cylinder discrimination value estimated from a previous cylinder discrimination value, and determines whether the cylinder discrimination is normal or abnormal based on the coincidence / mismatch between the two. The ignition control device for an internal combustion engine according to claim 1 or 2, wherein the ignition control device performs a diagnosis.