JPH0686856B2 - Control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an internal combustion engine, and in particular, in the range from about 90 degrees before TDC to TDC, the crankshaft does not have any timing. Even if it rotates in reverse,
The present invention relates to a control device for an internal combustion engine that can always control the internal combustion engine well.

(Prior Art) Starting of an internal combustion engine is performed, for example, by rotating a starter motor. When the internal combustion engine is not started by one operation of the starter motor, the crankshaft of the internal combustion engine is
It may be reversed by a certain angle and then stopped. Further, even when the engine is stalled, the crankshaft may reverse once and then stop.

When the ignition plug is ignited during the reverse rotation (returning) of the crankshaft, the internal combustion engine rotates in the reverse direction, or the angular position of the crankshaft and the ignition timing of the ignition plug arranged in each cylinder. When the internal combustion engine is restarted after being stopped, the ignition positions of the cylinders are extremely displaced due to incorrect distribution of the internal combustion engine, resulting in abnormal noise and unfavorable commercial conditions. Could occur.

In order to solve this drawback, if reverse rotation or stop of the internal combustion engine is detected, the spark plug does not ignite,
Alternatively, a technique has been developed for preventing the ignition position of each cylinder from being displaced when restarting after reverse rotation.

As an example of the technique, for example, Japanese Patent Publication No. 59-28751, is output every time the crankshaft is rotated by a fixed angle,
The pulse interval of the pulse for controlling the ignition timing is detected, and when the pulse interval is a predetermined time or more, it is considered that the internal combustion engine has reversely rotated, and at the time of restarting after the reverse rotation, for each cylinder, A technique is disclosed in which an ignition device is controlled so that the ignition position does not shift.

(Problems to be Solved by the Invention) The above-described conventional technique has the following problems.

According to the technique disclosed in Japanese Patent Publication No. 59-28751, when the pulse is output and a certain spark plug is discharged, or immediately after that, a reverse rotation occurs, the restart is performed after the reverse rotation. It is possible to keep the ignition timing of each cylinder in the optimum state.

However, depending on the timing of the reverse rotation, for example, when the reverse rotation occurs at a substantially intermediate time between the pulses output for each constant angle, the pulse intervals of the pulses output for each constant angle do not change much. Therefore, the reverse rotation may not be detected.

As a result, the spark plug may be ignited during the reverse rotation, causing the internal combustion engine to rotate in the reverse direction or generating an abnormal noise.

The present invention has been made to solve the above problems.

(Means and Action for Solving Problems) In order to solve the above problems, the present invention relates to a first constant angle detecting means for generating an output each time the internal combustion engine rotates at a constant angle, and an internal combustion engine. Generates an output each time it rotates the same angle as the constant angle, and the output of the first constant angle detecting means is less than 1/2 of the time interval of the output of the first constant angle detecting means. Second constant angle detecting means arranged to generate an output earlier than the first constant angle detecting means and measuring means for measuring the time interval between the outputs of the first and second constant angle detecting means are provided. Immediately before the time, the time measured by the measuring means is the time measured immediately before the stage at which the time interval is measured (this time means the time from the output of the first constant angle detecting means to the second constant The time until the output of the angle detection means and the second constant angle It is considered that the internal combustion engine is reversed, and the internal combustion engine is rotated in reverse when the time from the output of the degree detection means to the output of the first constant angle detection means is included). As a result, the reverse rotation can be detected no matter which position of the crank angle the reverse rotation starts in the range from around 90 degrees before TDC to TDC. Therefore, at least in the above range, the internal combustion engine can be controlled under optimum conditions at all times.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 1 shows an embodiment in which the present invention is applied to a V-type engine.

In the figure, a rotor 1 is fixed to a crankshaft of the internal combustion engine or a shaft that rotates in synchronization with the crankshaft. Around the rotor 1, for example, every 45 degrees, claws
Only 1A is placed. That is, the nail 1A,
It is not arranged in the portion indicated by reference numeral 1B in FIG.

The first and second pulsars 2 and 3 are sensors for detecting passage of the claw 1A, and are arranged on the outer circumference of the rotor 1 with respect to the center thereof, for example, 135 degrees (45 degrees x 3) or more. It is arranged so as to form a slightly smaller angle θ. Therefore,
When the rotor 1 rotates in the direction of arrow A, the second pulsar 3 moves at a timing earlier than the first pulsar 2
Detect 1A.

The output line of the second pulser 3 is connected to the set input terminal S of the flip-flop 4.

The reset input terminal R of the flip-flop 4 is connected to the clear output terminal CL of the CPU 5 described later, and the output terminal Q of the flip-flop 4 is the second input terminal of the CPU 5.
It is connected to C2.

The output line of the first pulser 2 is the first input terminal of the CPU5.
It is connected to C1.

The first output terminal A of the CPU5 is a soft-off switch 6
Is connected to the input terminal I of the first transistor 11 and the second output terminal B of the CPU 5 is also connected to the input terminal I of the soft-off switch 6 and the base of the second transistor 12. There is. In addition, the third of the CPU5
Is a control terminal U of the soft-off switch 6.
Further, the power supply terminal P is connected to one terminal of the ignition switch 7.

The output terminal O of the soft-off switch 6 is grounded.

The ignition switch 7 and the battery 8, the first and second transistors 11 and 12, the first and second ignition coils 13 and 14, and the first and second ignition plugs 15 and 16 are respectively illustrated. Are connected as.

The flip-flop 4 receives the output signal of the second pulser 3 and outputs a control signal from the output terminal Q to the CPU 5. Then, the control signal is a clear output terminal of the CPU5.
It is reset by the clear signal output from CL.

The clear signal of the CPU 5 is output when the first pulser 2 generates an output signal and the control signal is output from the output terminal Q.

The soft-off switch 6 is, for example, a CR circuit, and when a control signal is supplied to its control terminal U,
The current flowing through the bases of the first and second transistors 11 and 12 is reduced with a certain time constant so that the first and second spark plugs 15 and 16 are not discharged.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS. 1 and 2 to 4.

2 is a flow chart showing the operation of the CPU 5 shown in FIG. 1, FIG. 3 is a flow chart showing the details of the interrupt routine shown in step S13 of FIG. 2, and FIG.
3 is a time chart showing output waveforms of the main constituent elements shown in FIG. 1, showing a state in which the internal combustion engine is rotating normally.

First, when the ignition switch 7 (FIG. 1) is turned on, for example, a starter (not shown) is rotated, and the crankshaft of the internal combustion engine, that is, the rotor 1 is rotated in the arrow A direction. Then, the processing shown in FIG. 2 starts.

In the flowchart of FIG. 2, step S1
After 1, the interrupt routine of step S13 is executed by the interrupt of the first pulse described later. Then, in steps S1 to S10, the interrupt by the first pulse is prohibited.

First, in step S1, the first pulser 2 detects the claw 1A, and it is determined whether or not the output thereof is generated. In the following description, the output pulse of the first pulser 2 will be referred to as the first pulse.
Called the pulse of.

If the first pulse is detected, then, in step S2, T1, which will be described later, is fetched and stored in the memory of the CPU 5. The T1 is the first pulse or the second pulser 3
Output pulse (hereinafter referred to as the second pulse) from the time when the next first pulse is generated, for example, clock output by an internal counter (not shown) provided in the CPU5. It is measured by counting the pulses.

Next, in step S3, it is detected whether or not the output of the flip-flop 4 (hereinafter, simply referred to as Q output) is "0" when the first pulse is generated. If not "0", in step S4, a clear signal is output from the clear output terminal CL of the CPU 5, the flip-flop 4 is reset, and the process returns to step S1 again.

If it is determined in step S3 that the Q output is "0", it is determined in step S5 whether T1 is longer than a preset time T0. If T1 is larger than T0, it is determined that the rotor 1 is stopped or reversely rotated, and the process returns to step S1.

If T1 is smaller than T0, it is determined that the rotor 1 is rotating at a certain angular velocity or higher, and in step S6,
The stage number ST is defined as 1. The stage number ST
Is set every time the first pulse is output, and in this embodiment, stage numbers 1 to 7 are set while the rotor 1 makes one revolution.

Next, in step S7, it is determined whether or not the second pulse has been output. When the second pulse is output,
In step S8, N is set to 1, and in step S9, T2 (N) is input. T2 (N)
Is the time from the time when the first pulse is generated to the time when the second pulse is generated, and is measured by counting the clock output pulses by the internal counter of the CPU 5, as in T1.

Next, at step S10, it is judged if T2 (N) is greater than a preset time T01. T
If 2 (N) is larger than T01, it is determined that the rotor 1 is stopped or in reverse rotation, and the process is stepped.
Return to S1. If T2 (N) is smaller than T01, rotor 1
Is determined to be rotating at a predetermined angular velocity or higher, and the interrupt-disabled state by the first pulse is released in step S11.

Then, in step S12, it is judged again whether or not the first pulse has risen, and if it rises, the interrupt routine of step S13 is executed. If the interrupt routine has been executed, the process returns to step S12 again.

The interrupt routine is shown in FIG. The interrupt routine detects once whether or not the second pulse is output. The stage number ST is incremented by 1 by executing the interrupt routine once.

First, in step S21, T1 is input, and then step S
At 22, it is judged if the Q output is "0". If the Q output is not "0", the stage number ST is incremented by 1 in step S23, a clear signal is output from the clear output terminal CL of the CPU 5 in step S24, and the Q output is reset.

If the Q output is "0", the stage number ST is set to 1 in step S25.

Next, in step S26, it is determined whether T2 (N) is larger than T1. T1 is the value input in step S21. T2 (N) is the value input in step S9 when this interrupt routine is executed for the first time after the processing steps shown in FIG. 2, and the interrupt routine interrupts the first pulse. When it is executed twice or more, the value is input in step S36 described later.

Now, as is clear from FIG. 4, T1 is always smaller than T2 (N) except when measured by the stages 5 and 7 when the rotor 1 is rotating normally. Therefore, if T2 (N) is smaller than T1, it is determined that the internal combustion engine is stopped or in the reverse rotation state, and step S29 is performed.
In step 1, the soft-off switch 6 is operated to turn off the first transistor 11 or the second transistor 12 with a certain time constant so that the first spark plug 15 or the second spark plug 16 is not discharged (hereinafter , Soft off). Then, the process moves to step S30.

If T2 (N) is larger than T1, it is determined in step S27 whether the stage number ST is 3, and if it is 3, in step S28, the first transistor 11
After turning off, that is, the first output terminal A of CPU5
Shut off the output and ignite the first spark plug 15,
The process moves to step S30. If the stage number ST is not 3, the process directly goes to step S30.

In step S30, as in step S5, it is determined whether T1 input in step S21 is larger than T0 set in advance.If T1 is larger, the internal combustion engine is stopped or reversely rotated. Is judged to be
The process returns to step S1 in FIG.

If T1 is not larger than T0, in step S31,
It is determined whether or not the stage number ST is 2. If the stage number ST is 2, in step S32, the first transistor 11 is turned on, that is, the control signal is output from the first output terminal A of the CPU 5, and then the process proceeds to step S33. . If the stage number ST is not 2, the process directly goes to step S33.

Steps S33 and S34 are a loop that determines whether the second pulse or the first pulse is output. If the second pulse is detected in step S33, the process goes to step S35. If the first pulse is detected in step S34, the process returns to step S21.

In step S35, 1 is added to N for defining T2 for each stage, and in step S36, T2 (N) is input.

Next, in step S42, as in step S10,
The T2 (N) input in the step S36 is compared with the preset T01. If T2 (N) is larger than T01, it is determined that the internal combustion engine is stopped or reversely rotated, and the process is executed. Return to step S1. If T2 (N) is not larger than T01, it is determined in step S43 whether the stage number ST is 4. If the stage number ST is 4, in step S44, after the second transistor 12 is turned on, that is, the second output terminal B of the CPU 5
After the control signal is output from the step S37,
Move to. If the stage number ST is not 4, the process directly goes to step S37.

In step S37, as in step S26, T2
(N) is compared with T1, and if T2 (N) is smaller than T1, the soft-off switch 6 is operated in step S41, and then the process returns to step S12. T2 (N)
Is larger than T1, it is determined in step S38 whether the stage number ST is 5. Stage number
If ST is not 5, the process returns to step S12, 5
If so, the process proceeds to step S39.

In step S39, it is determined whether T2 (N) is larger than T2 (N-1). And T2 (N) is T2
If it is smaller than (N-1), it is determined that the internal combustion engine is in a stopped or reverse rotation state, and step S41
At, the soft-off switch 6 is activated, and T2 (N)
Is larger than T2 (N-1), the second transistor 12 is turned off in step S40. Ie CP
The output of the second output terminal B of U5 is shut off and the second spark plug 16 is ignited. Then, the process thereafter returns to step S12.

Here, in step S39, T2 (N) is equal to T2 (N
The reason why it is determined that the internal combustion engine is in the stopped state or the reverse rotation state when it is smaller than -1) will be described with reference to FIG.

FIG. 5 is a graph showing the relationship between the engine speed, in other words, the angular velocity of the crankshaft and the time when the internal combustion engine is normally rotating at the time of starting. Further, FIG. 5 shows a state in which the crankshaft makes one revolution.

As is clear from Fig. 5, the compression top dead center TDC at the start
1, TDC2 (in other words, the first and second transistors 11,1
If the internal combustion engine is operating normally within a range of about 90 degrees before (from the time when 2 is turned off), the engine speed will always drop.

Here, in step S39, the time T2 (N) from the start of the stage 5 in FIG. 4 to the first output of the second pulse in the stage 5, that is, the second transistor 12 is turned off. About 45 degrees before the crank angle-and T2 (N-
1) -that is, the range between about 45 degrees before and about 90 degrees before the crank angle at which the second transistor 12 is turned off-and if the internal combustion engine is operating normally, the stage T2 (N) in 5 is always larger than T2 (N-1) in stage 4. And this T2
If the magnitude relationship between (N) and T2 (N-1) is reversed,
It can be determined that the internal combustion engine is stopped or reversely rotated.

Now, when the internal combustion engine is rotating normally in the specified direction, the first pulse and the second pulse are
As shown in the figure, the CPU 5 executes the processing shown in FIGS. 2 and 3 by the first and second pulse outputs. As a result, the first transistor 11 is turned on at the beginning of stage 2, and the first transistor 11 is turned off (the first spark plug 15 is ignited) at the beginning of stage 3. Also, when the second pulse is output in stage 4, the second transistor 12 is turned on,
When the second pulse is first output in stage 5, the second transistor 12 is turned off (the second spark plug 16 is ignited).

Next, the operation of the embodiment of the present invention when the internal combustion engine is reversed will be described with reference to the flowcharts shown in FIGS. 6 to 8 and FIG.

FIG. 6 is a time chart showing the operation of the embodiment of the present invention when the reverse rotation occurs when the first transistor 11 is turned on.

The stage number ST shown in FIG. 6 corresponds to step S2.
The stage number ST counted at 3, and the one shown in parentheses shows the actual stage number ST.

First, when reverse rotation occurs when the first transistor 11 is turned on, the first and second pulse outputs output the first pulse indicating the start of stage 2 as shown in FIG. To be almost symmetrical with respect to the time point
Will be output.

The time T2 (N) from the start of stage 2 to the output of the second pulse is input in step S36, and T2 (N) is input.
And T1 immediately before it are compared in step S37.

As is clear from the comparison with FIG. 4, if the rotation is normal, the T2 (N) in the stage 2 is longer than the T1, but the reverse rotation occurs when the first transistor 11 is turned on. And the T2 (N) and the T1 substantially match,
The processing of the CPU 5 shifts from step S37 to step S41.
Then, in step S41, the control signal is output from the third output terminal C of the CPU 5, the soft-off switch 6 is turned on, and the first transistor 11 is soft-off.

If the speed of the crankshaft at the start of reverse rotation is higher than the speed of the crankshaft immediately before the start of reverse rotation, the T2
Since (N) becomes longer than T1, the process cannot proceed from step S37 to step S41.
Therefore, at this time (when the second pulse is output in stage 2), the first transistor 11 cannot be soft-off.

Therefore, in this case, the first transistor 11 is soft-off when the first pulse indicating the start of the stage 3 is output. That is, when the processing shifts from step S37 to step S38, thereafter, in step S12, the output of the first pulse indicating the start of the stage 3 is detected. Then, the time T1 from the second pulse output of the stage 2 to the start of the stage 3 is input in step S21, and the T1 and T2 (N) in the stage 2 are compared in step S26. As is apparent from FIG. 6, T1 of the stage 2 is always larger than T2 (N) of the stage 2, so the process shifts from step S26 to step S29, and in this step S29, the first transistor 11
Is soft-off. This soft-off is indicated by a chain double-dashed line in FIG.

FIG. 7 is a time chart showing the operation of the embodiment of the present invention when the reverse rotation occurs immediately before the second transistor 12 is turned on.

If a reversal occurs immediately before the second transistor 12 is turned on, that is, a reversal occurs before the second pulse is output in stage 4, the output of the first and second pulses will cause the reversal to occur. The output is almost symmetrical with respect to the time point.

The ON operation of the second transistor 12 is as described above.
This is performed when the second pulse is output in stage 4, but in this case, the second pulse is output in stage 4.
While waiting for the pulse output of (step S33), the first pulse is output and
After S33, the process goes to step S21 through step S34. Then, after that, in step S23, the stage number ST is defined as 5, so that the second transistor 12 is not turned on during this reverse rotation.

FIG. 8 is a time chart showing the operation of the embodiment of the present invention when the reverse rotation occurs immediately after the second transistor 12 is turned on.

Immediately after the second transistor 12 is turned on, that is,
When the reverse rotation occurs immediately after the second pulse is output in the stage 4, the first and second pulses are output so as to be substantially symmetrical with respect to the time when the reverse rotation occurs.

When the second transistor 12 confirms that the stage number ST is 4 in step S43 after confirming the second pulse output in step S33,
At S44, it turns on. Then, after that, the process returns to step S12 and waits for the first pulse to be output.

Therefore, as shown in FIG. 8, even if the second pulse is output again after the second transistor 12 is turned on, a clear signal is output from the clear output terminal CL of the CPU 5, T1 or T2 (N) will not be input.

Then, after that, when the first pulse is input, the interrupt routine shown in step S13 is executed again.

When the first pulse is input, the time T1 from when the second transistor 12 is turned on to when the stage 5 is started is input in step S21. And step S2
At 6, the T1 is compared with the time T2 (N) from the start of stage 4 until the second transistor 12 turns on. Then, in this case, it is determined that T1 is longer than T2 (N), the soft-off switch 6 is turned on, and the second transistor 12 is soft-off in step S29.

If T1 is not longer than T2 (N), or if the ON operation of the soft-off switch 6 in step S29 is configured to softly turn off only the first transistor 11, the input is made in step S36. , The time T2 (N) from the start of the stage 5 to the time when the second pulse is input in the stage 5 is first the step S42.
In, it is compared with the preset T01. If the time T2 (N) is smaller, the time T2 (N)
And the second transistor 12 input in step S21.
Is turned on and the time T1 from the start of stage 5 is compared in step S37, and when it is determined that T2 (N) is smaller than T1, the second transistor 12 is turned on in step S41. Is soft-off.

Furthermore, in step S37, for some reason,
When it is not determined that T2 (N) is smaller than T1, or the interrupt routine is executed in step S37.
If the processing is not performed, step S3
After it is confirmed that the stage number ST is 5 in 8, in step S39, the above-mentioned T2 (N) and the time T2 (N2) before the start of the stage 4 until the second transistor 12 is turned on ( N-1) is compared. As is clear from FIG. 8, when the internal combustion engine is not rotating normally, the T2 (N) is always smaller than the T2 (N-1), and as a result, the process is started from step S39. In step S41, the second transistor 12 is surely soft-off.

In the description of FIG. 6, the reverse rotation occurs when the first transistor 11 is energized, but the reverse rotation occurs when the second transistor 12 is energized. The same applies when it occurs.

Further, in the description of FIGS. 7 and 8, immediately before the energization of the second transistor 12 is started and immediately after the energization is started,
Although the case where the reverse rotation occurs is described, the same applies to the case where the reverse rotation occurs immediately before the first transistor 11 is energized and immediately after the first transistor 11 is energized.

Further, in the above-described embodiments, the method for detecting the reverse rotation of the internal combustion engine according to the present invention is explained as being used only for the soft-off operation of the first transistor 11 or the second transistor 12 in the ignition device. However, it is needless to say that the present invention is not limited to this and is applied to all control devices controlled by reverse rotation detection of the internal combustion engine.

Further, as is clear from the above description, the engine speed is constantly decreasing in the range from around 90 degrees before TDC (that is, near the ignition timing) to TDC. Therefore, from step S42 and step S39 described above. As is clear
Simply, a means for generating an angular position pulse for each predetermined constant angle before the ignition timing and a means for measuring the pulse interval are provided, and the time interval at which the angular position pulse is generated immediately before the ignition control timing is longer than the predetermined time. Is also small, and is larger than the time interval of the section immediately before the immediately preceding time interval, it is determined to be the normal rotation state, otherwise it is determined to be the reverse rotation state. Alternatively, the control device for the internal combustion engine may be configured.

Furthermore, although the above-described embodiment has been described as being applied to a V-type engine, it goes without saying that it may be applied to any engine.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

That is, the first constant angle detection means that generates an output each time the internal combustion engine rotates by a constant angle, and the output that generates an output each time the internal combustion engine rotates by the same angle as the constant angle, and the first constant angle detection Second constant-angle detection means arranged so as to generate an output before the output of the first constant-angle detection means in a time period smaller than 1/2 of the time interval of the output of the means;
A measuring unit that measures the time from the output of the first constant angle detecting unit to the output of the second constant angle detecting unit is provided, and the time measured by the measuring unit immediately before the ignition timing is provided. When the time is smaller than the time measured by the measuring means immediately before the stage where the time is measured, it is considered that the internal combustion engine is reversed, so that the TDC is changed from around 90 degrees before TDC. In the range up to this point, no matter which position of the crank angle the reverse rotation starts, the reverse rotation can be reliably detected.

Therefore, in the ignition device, when the reverse rotation occurs in the range from around 90 degrees before the TDC to the TDC, it is possible to surely prevent the spark plug from igniting, or again after the reverse rotation. It is of course possible to set the ignition timing to each cylinder at the time of start-up to an optimum state at all times, and it is possible to always maintain a normal control state by the reverse rotation detection in all control devices.

As a result, the reliability of the control device for the internal combustion engine can be increased and the commercialability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flow chart showing the operation of the CPU, and FIG. 3 is a flow chart showing the details of the interrupt routine shown at step S13 in FIG. FIG. 4 is a time chart showing the output waveforms of the main components of one embodiment of the present invention when the internal combustion engine is rotating in the normal direction, and FIG. 5 is the internal combustion engine rotating in the normal direction. 6 to 8 are graphs showing the relationship between the engine speed and the time when the internal combustion engine is rotating, and FIGS. 6 to 8 are time charts showing the output waveforms of the main constituent elements of one embodiment of the present invention when the internal combustion engine is reversed. is there. 1 ... Rotor, 1A ... Claw, 2 ... First pulser, 3 ...
Second pulser, 4 ... Flip-flop, 5 ... CPU,
6 ... Soft-off switch, 11 ... First transistor, 12 ... Second transistor, 13 ... First ignition coil, 14 ... Second ignition coil, 15 ... First spark plug, 16 …… Second spark plug

Claims (2)

[Claims] Claim: What is claimed is: 1. First constant angle detecting means for producing an output each time the internal combustion engine rotates by a constant angle, and an output for each time the internal combustion engine rotates by the same angle as the constant angle, and the first constant angle detecting means. A second constant angle detecting means arranged so as to generate an output earlier than the output of the first constant angle detecting means in a time smaller than 1/2 of the time interval of the output of the constant angle detecting means. Measuring means for measuring the time interval between the outputs of the first and second constant angle detecting means, and the time measured by the measuring means immediately before the ignition timing is measured just before the time is measured. Reverse rotation detection means for generating a reverse rotation detection output when the time is shorter than the time measured by the means, and control means for controlling the internal combustion engine according to the output of the reverse rotation detection means. Control device for internal combustion engine. 2. A first constant angle detecting means for generating an output each time the internal combustion engine rotates by a constant angle, and an output for each time the internal combustion engine rotates by the same angle as the constant angle, and the first constant angle detecting means. A second constant angle detecting means arranged so as to generate an output earlier than the output of the first constant angle detecting means in a time smaller than 1/2 of the time interval of the output of the constant angle detecting means. Measuring means for measuring the time interval between the outputs of the first and second constant angle detecting means, and the time measured by the measuring means immediately before the ignition timing is measured just before the time is measured. Reverse rotation detection means for generating a reverse rotation detection output when the time is shorter than the time measured by the means, and the primary current of the ignition coil is gradually increased in accordance with the output of the reverse rotation detection means so that the ignition plug is not discharged. Softening off An internal-combustion-engine control device comprising: