JP3863460B2 - Ignition control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine ignition control device.
[0002]
[Prior art]
The ignition timing is controlled in order to obtain an optimum output or improve the fuel consumption in accordance with the engine load state or driving state. Conventionally, an acceleration state or a deceleration state of a vehicle is detected by a change in throttle opening, and ignition timing is controlled according to the acceleration / deceleration state. For example, in a motorcycle, the output may be reduced to prevent a wheelie (lifting up the front wheel) when the throttle is suddenly opened at the time of starting, or the output may be increased to improve acceleration during normal acceleration. Done. In such a case, the output is reduced by correcting to the retard side with respect to the ignition timing during normal traveling, and the output is increased by correcting to the advance side.
[0003]
Conventionally, a throttle position sensor for detecting the throttle opening and a throttle position detection circuit connected thereto are used for such acceleration / deceleration discrimination.
[0004]
[Problems to be solved by the invention]
However, if a throttle position sensor or a throttle position detection circuit is used, the number of parts increases, the structure of the control system becomes complicated, and the cost of the vehicle increases because the parts themselves are expensive. Especially in small vehicles, the space around the engine is limited, so there is a problem with the component installation layout. If the installation space for the throttle position sensor cannot be obtained or is installed, it is larger than the layout of other components. There were cases where it was a limitation.
[0005]
The present invention takes the above-described conventional technology into consideration, and accurately determines the acceleration / deceleration state without using a dedicated sensor for detecting the throttle opening, such as a throttle position sensor. It is another object of the present invention to provide an ignition control device that can improve fuel consumption.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a rotation speed detection unit that calculates a rotation speed from a rotation detection signal of the crankshaft, a rotation fluctuation degree detection unit that calculates a rotation fluctuation degree from the rotation detection signal of the crankshaft, A rotation fluctuation degree change detection unit that calculates a change in the rotation fluctuation degree, an output correction determination part that determines whether to correct an increase or decrease in output based on the rotation fluctuation degree and / or the change, and the output An output correction calculation unit that calculates an advance amount or a retard amount of the ignition timing corresponding to an increase or decrease of the ignition timing; and an ignition timing determination unit that calculates an ignition timing based on the advance amount or the retard amount of the ignition timing; An ignition control device is provided.
[0007]
According to this configuration, the operating state of acceleration / deceleration is detected based on the rotational fluctuation degree of the crankshaft or the change thereof, and the correction of the increase / decrease of the output is determined according to this, and the ignition is performed corresponding to the increase / decrease amount of the output In order to advance or retard the timing, the acceleration / deceleration state can be detected without using a special throttle position detection sensor, and the ignition timing can be controlled accordingly. And fuel consumption can be improved.
[0008]
That is, the present invention utilizes the phenomenon that the degree of crankshaft rotation variation varies with engine load, and the operation state such as crankshaft rotation and acceleration / deceleration according to the engine load from the degree of crankshaft rotation variation. And the optimum ignition timing is calculated. At this time, the optimum ignition timing can be calculated more accurately by determining the operating state based on the change in the degree of rotational fluctuation.
[0009]
In a preferred configuration example, a protrusion having a predetermined length is formed on a flywheel attached to the crankshaft, and a pickup coil for detecting the protrusion is provided. The pickup coil detects rotation of the crankshaft, and the rotation fluctuation The degree detection unit measures the crankshaft cycle T based on the detection time t of the ridge detection unit and the detection time interval of the rotation detection signal of the crankshaft, and the ratio t of the ridge detection time t to the cycle T / T is calculated as the rotation fluctuation degree D.
[0010]
According to this configuration, since the detection time t of the protrusion provided on the flywheel rotating synchronously with the crankshaft changes according to the rotation fluctuation of the crankshaft with respect to the cycle T of one rotation of the crankshaft, The operating state can be determined by detecting the flywheel ridges that rotate synchronously with the pickup coil, analyzing the detection signal, and calculating t / T as the degree of rotational fluctuation D. The engine can be applied to a 2-cycle engine or a 4-cycle engine.
[0011]
In a more preferable configuration example, the rotation variation degree change detection unit is based on the rotation variation degree t / T and the rotation variation degree t ′ / T ′ of the next cycle as the change D ′ of the rotation variation degree, and the difference between them. It is characterized in that t / T−t ′ / T ′ is calculated as a change D ′ in the rotational fluctuation degree.
[0012]
According to this configuration, in the continuous rotation cycle of the crankshaft, the above-described difference in the rotation fluctuation degree t / T is calculated to obtain the rotation fluctuation degree change D ′, and this D ′ is used as a criterion for determining the driving state. Therefore, more accurate ignition timing control can be performed.
[0013]
In the case of a two-cycle engine, the difference in the degree of rotational fluctuation is calculated between one rotation of the crankshaft and the next rotation following this.
[0014]
In the case of a four-cycle engine, the difference in rotational fluctuation may be obtained between the compression stroke and the exhaust stroke in one cycle (two rotations), or between the compression strokes or between the exhaust strokes in successive cycles. You may obtain | require the difference of a rotation fluctuation degree between.
[0015]
In a further preferred configuration example, a rotation fluctuation degree integration unit that calculates an integral value of the rotation fluctuation degree is provided, and the rotation fluctuation degree integration part is connected to the output correction determination unit.
[0016]
According to this configuration, in addition to the change in the degree of rotational fluctuation, the integrated value of the degree of rotational fluctuation up to that time is calculated and used as a criterion for determining the driving state. The ignition timing can be accurately controlled in each acceleration state, and the vehicle travels based not only on the momentary acceleration / deceleration change but also on the driving state including the state before the change occurred. The feeling can be improved.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram illustrating the configuration of rotation detection means according to the present invention.
[0018]
A flywheel 2 is attached to the end of the crankshaft 1 of the engine. The flywheel 2 may constitute a rotor of a generator. On the outer periphery of the flywheel 2, a protrusion 3 having a predetermined length (for example, an angle range of 60 °) is formed. A pickup coil 4 for detecting the protrusion 3 is fixed to the engine case side. The pickup coil 4 detects a change in the magnetic resistance of the coil based on a change in the magnetic field when the protrusion 3 approaches. As this pickup coil, a conventional ignition timing detection coil may be used.
[0019]
When the flywheel 2 rotates in the direction of the arrow and the pickup coil 4 detects the protrusion 3, a rotation detection signal b having a protrusion a is obtained as shown in FIG. In the actual signal, a positive pulse is generated at the tip of the protrusion 3 and a negative pulse is generated at the rear end.
[0020]
The period T is detected by measuring the time interval between the two adjacent protrusions a (from the front end to the front end or from the rear end to the rear end). The rotational speed is obtained from the reciprocal of the period T.
[0021]
A ratio t / T between the detection time t of the protrusion a and the period T is calculated as the rotation fluctuation degree D. Similarly, the detection time t ′ and period T ′ of the next rotation protrusion are measured, and the ratio t ′ / T ′ is calculated as the rotation fluctuation degree D ′. A difference DD ′ between the rotational fluctuation degrees D and D ′ is calculated as a change in the rotational fluctuation degree. Based on these D and DD ′, the operating state is determined and the ignition timing is controlled as described later.
[0022]
FIG. 2 is a block diagram of the ignition control device according to the present invention.
The ignition control device 5 includes an arithmetic circuit 6, a power supply circuit 7, and an ignition circuit 8. The power supply circuit 7 is connected to the battery 10 via the main switch 9. The ignition circuit 8 is connected to an ignition coil 11 and further connected to an ignition plug of a cylinder head (not shown). The aforementioned pickup coil 4 (FIG. 1) is connected to the arithmetic circuit 6.
[0023]
The arithmetic circuit 6 includes a rotation speed detection unit 12, a rotation variation degree detection unit 13, a rotation variation degree change detection unit 14, an output correction determination unit 15, an output correction calculation unit 16, and an ignition timing determination unit 17. Composed.
[0024]
The rotational speed detector 12 calculates the rotational speed from the detection signal from the pickup coil 4 as described above. As described above, the rotation fluctuation degree detection unit 13 and the rotation fluctuation degree change detection unit 14 calculate the rotation fluctuation degree D and the rotation fluctuation degree change D ′ from the detection signal from the pickup coil 4, respectively.
[0025]
The output correction determination unit 15 compares the rotation fluctuation degree change D ′ with a predetermined reference value to determine whether it is necessary to correct the output increase or output decrease as compared with the normal operation. In addition to the rotational fluctuation degree D ′, the rotational fluctuation degree D may be compared with a predetermined reference value to determine whether output increase or output decrease correction is necessary.
[0026]
The output correction calculation unit 16 calculates an ignition advance amount or a retard amount in order to increase or decrease the engine output according to the determination result of the output increase or decrease. It is desirable to determine the ignition advance amount or retard amount based not only on the rotational fluctuation degree D and / or the rotational fluctuation degree change D ′ but also based on the rotational speed and calculate the output control amount. As a result, the ignition timing can be controlled more finely according to each of the high-speed rotation and the low-speed rotation.
[0027]
The ignition timing determination unit 17 determines the basic ignition timing during normal operation based on the rotational speed, the engine load, and the like, and the ignition timing correction amount calculated by the output correction calculation unit 16 with respect to this basic ignition timing as described above. Are added or subtracted to generate a final ignition signal. Based on this ignition signal, the ignition coil 11 is driven via the ignition circuit 8 to ignite the ignition plug of the engine.
[0028]
FIG. 3 is a block diagram of another embodiment of the present invention. This embodiment is for limiting the output at the time of sudden acceleration at the start to prevent a wheelie of a motorcycle. The functions of this embodiment are included in the functions of the above-described embodiment of FIG. 2, and FIG. 3 is obtained by changing a part of the block configuration of FIG.
[0029]
That is, in this embodiment, an output decrease determining unit 15a that determines whether or not output decrease correction is necessary based on the rotation fluctuation degree D and / or its change D ′ is provided corresponding to the output correction determining unit 15 of FIG. A retard amount calculation unit 16a that calculates an ignition retard amount based on the determination result is provided. Other configurations and operations are the same as those in the example of FIG.
[0030]
FIG. 4 is a block diagram of still another embodiment of the present invention.
In this embodiment, a rotational acceleration detector 18 connected to the rotational speed detector 12 is provided, and the acceleration is calculated by differentiating the speed signal. This rotational acceleration signal is input to the output decrease determination unit 15a, and it is determined whether or not to limit the output based on the acceleration in addition to the aforementioned D and D '. Other configurations and operations are the same as those of the embodiment of FIG.
[0031]
FIG. 5 is a flowchart showing the operation of the embodiment shown in FIGS.
Step A1:
The rotation fluctuation degree detection unit 13 calculates the rotation fluctuation degree D.
Step A2:
The rotation fluctuation degree change detecting unit 14 calculates a change D ′ of the rotation fluctuation degree within a predetermined time.
Step A3:
The output decrease determining unit 15a determines whether the rotation fluctuation degree D is equal to or greater than a predetermined reference value D0.
[0032]
Step A4:
When D is less than D0 in step A3, that is, when the degree of fluctuation in rotation is small, the ignition timing determination unit 17 calculates the basic ignition timing α in the normal travel mode.
Step A5:
When D is equal to or greater than D0 in step A3, the output decrease determination unit 15a determines whether or not the rotational fluctuation degree change D ′ is equal to or greater than a predetermined reference value D′ 0.
[0033]
Step A6:
When D ′ is equal to or greater than D′ 0, the retardation amount calculation unit 16a calculates the retardation amount β.
Step A7:
When D ′ is less than D′ 0, the retard amount calculator 16a calculates the retard amount γ.
Step A8:
The ignition timing determination unit 17 calculates a final ignition timing (α−β) obtained by subtracting and correcting the retardation amount β from the basic ignition timing α.
[0034]
Step A9:
The ignition timing determination unit 17 calculates a final ignition timing (α−γ) obtained by subtracting and correcting the retardation amount γ from the basic ignition timing α.
Step A10:
The ignition coil 11 is driven via the ignition circuit 8 based on the final ignition timing α, (α−β) or (α−γ) calculated by the ignition timing determination unit 17 to ignite the ignition plug of the engine.
[0035]
FIG. 6 is a block diagram of another embodiment of the present invention.
In this embodiment, a rotation fluctuation degree integration unit 19 connected to the rotation fluctuation degree detection unit 13 is provided. Thus, in addition to the change in the degree of rotation fluctuation, the operating state can be further discriminated using the integrated value of the degree of rotation fluctuation so far as a determination factor to obtain the optimum ignition timing retardation correction amount. Other configurations and operations are the same as those in the example of FIG.
[0036]
FIG. 7 is a block diagram of still another embodiment of the present invention.
In this embodiment, a rotational acceleration detector 18 connected to the rotational speed detector 12 is provided, and the acceleration is calculated by differentiating the speed signal. This rotational acceleration signal is input to the output decrease determination unit 15a, and it is determined whether or not to limit the output based on the acceleration in addition to the aforementioned D, D 'and the integral value. Other configurations and operations are the same as those of the embodiment of FIG.
[0037]
FIG. 8 is a flowchart art showing the operation of the embodiment shown in FIGS.
Step B1:
The rotation fluctuation degree detection unit 13 calculates the rotation fluctuation degree D.
Step B2:
The rotation fluctuation degree change detecting unit 14 calculates a change D ′ of the rotation fluctuation degree within a predetermined time.
Step B3:
A rotation fluctuation degree integration unit 19 calculates an integral value ∫D of the rotation fluctuation degree.
[0038]
Step B4:
The output decrease determining unit 15a determines whether the rotation fluctuation degree D is equal to or greater than a predetermined reference value D0.
Step B5:
When D is less than D0 in step B4, that is, when the degree of fluctuation in rotation is small, the ignition timing determination unit 17 calculates the basic ignition timing α in the normal travel mode.
[0039]
Step B6:
When D is equal to or greater than D0 in step B4, the output decrease determination unit 15a determines whether or not the rotational fluctuation degree change D ′ is equal to or greater than a predetermined reference value D′ 0.
Step B7:
When D ′ is equal to or greater than D′ 0 in step B6, the output decrease determination unit 15a determines whether or not the integral value ∫D is equal to or greater than a predetermined reference value ０D0.
[0040]
Step B8:
When D ′ is less than D′ 0 in step B6, the output decrease determination unit 15a determines whether the integral value ∫D is equal to or greater than a predetermined reference value ∫D0.
Step B9:
When ∫D is greater than or equal to ∫D0 in step B7, the retardation amount calculation unit 16a calculates the retardation amount β.
[0041]
Step B10:
When ∫D is less than ∫D0 in step B7, the retardation amount calculation unit 16a calculates the retardation amount γ.
Step B11:
The ignition timing determination unit 17 calculates a final ignition timing (α−β) obtained by subtracting and correcting the retardation amount β from the basic ignition timing α.
[0042]
Step B12:
The ignition timing determination unit 17 calculates a final ignition timing (α−γ) obtained by subtracting and correcting the retardation amount γ from the basic ignition timing α.
Step B13:
When ∫D is greater than or equal to ∫D0 in step B8, the retardation amount calculation unit 16a calculates the retardation amount δ.
[0043]
Step B14:
When ∫D is less than ∫D0 in step B8, the retard amount calculation unit 16a calculates the retard amount ε.
Step B15:
The ignition timing determination unit 17 calculates a final ignition timing (α−δ) obtained by subtracting and correcting the retardation amount δ from the basic ignition timing α.
[0044]
Step B16:
The ignition timing determination unit 17 calculates a final ignition timing (α−ε) obtained by subtracting and correcting the retardation amount ε from the basic ignition timing α.
Step B17:
The ignition coil 11 is driven via the ignition circuit 8 based on the final ignition timing α, (α−β), (α−γ), (α−δ) or (α−ε) calculated by the ignition timing determination unit 17. Then ignite the spark plug of the engine.
[0045]
FIG. 9 is a block diagram of another embodiment of the present invention. This embodiment is for increasing the output at the time of acceleration from the normal running state to improve the acceleration performance. The functions of this embodiment are included in the functions of the above-described embodiment of FIG. 2, and FIG. 9 is obtained by changing a part of the block configuration of FIG.
[0046]
That is, in this embodiment, an output increase determination unit 15b that determines whether or not output increase correction is necessary based on the rotation fluctuation degree D and / or its change D ′ is provided corresponding to the output correction determination unit 15 of FIG. Further, an advance amount calculation unit 16b for calculating the ignition advance amount based on the determination result is provided. Other configurations and operations are the same as those in the example of FIG.
[0047]
FIG. 10 is a block diagram of still another embodiment of the present invention.
In this embodiment, a rotational acceleration detector 18 connected to the rotational speed detector 12 is provided, and the acceleration is calculated by differentiating the speed signal. This rotational acceleration signal is input to the output increase determination unit 15b, and it is determined whether or not the output is increased based on the acceleration in addition to the aforementioned D and D ′. Other configurations and operations are the same as those of the embodiment of FIG.
[0048]
FIG. 11 is a flowchart showing the operation of the embodiment shown in FIGS.
Step C1:
The rotation fluctuation degree detection unit 13 calculates the rotation fluctuation degree D.
Step C2:
The rotation fluctuation degree change detecting unit 14 calculates a change D ′ of the rotation fluctuation degree within a predetermined time.
[0049]
Step C3:
The output increase determination unit 15b determines whether the rotation fluctuation degree D is equal to or greater than a predetermined reference value D0.
Step C4:
When D is less than D0 in step C3, that is, when the degree of fluctuation in rotation is small, the ignition timing determination unit 17 calculates the basic ignition timing α in the normal travel mode.
[0050]
Step C5:
When D is greater than or equal to D0 in step C3, the output increase determination unit 15b determines whether or not the rotation variation degree change D ′ is greater than or equal to a predetermined reference value D′ 0.
Step C6:
When D ′ is equal to or greater than D′ 0, the advance amount calculation unit 16b calculates the advance amount β.
[0051]
Step C7:
When D ′ is less than D′ 0, the advance amount calculation unit 16b calculates the advance amount γ.
Step C8:
The ignition timing determination unit 17 calculates the final ignition timing (α + β) corrected by adding the advance amount β to the basic ignition timing α.
[0052]
Step C9:
The ignition timing determination unit 17 calculates the final ignition timing (α + γ) corrected by adding the advance amount γ to the basic ignition timing α.
Step C10:
Based on the final ignition timing α, (α + β) or (α + γ) calculated by the ignition timing determination unit 17, the ignition coil 11 is driven via the ignition circuit 8 to ignite the ignition plug of the engine.
[0053]
FIG. 12 is a block diagram of another embodiment of the present invention.
In this embodiment, a rotation fluctuation degree integration unit 19 connected to the rotation fluctuation degree detection unit 13 is provided. As a result, in addition to the change in the degree of rotation fluctuation, the operating state can be more finely discriminated using the integrated value of the degree of rotation fluctuation up to that point as a determination factor, so that the optimal ignition timing advance correction amount can be obtained. Other configurations and operations are the same as those in the example of FIG.
[0054]
FIG. 13 is a block diagram of still another embodiment of the present invention.
In this embodiment, a rotational acceleration detector 18 connected to the rotational speed detector 12 is provided, and the acceleration is calculated by differentiating the speed signal. This rotational acceleration signal is input to the output increase determination unit 15b, and it is determined whether or not output increase correction is to be performed based on the acceleration in addition to the aforementioned D, D ′ and integral values. Other configurations and operations are the same as those of the embodiment of FIG.
[0055]
FIG. 14 is a flowchart art showing the operation of the embodiment shown in FIGS.
Step D1:
The rotation fluctuation degree detection unit 13 calculates the rotation fluctuation degree D.
Step D2:
The rotation fluctuation degree change detecting unit 14 calculates a change D ′ of the rotation fluctuation degree within a predetermined time.
[0056]
Step D3:
A rotation fluctuation degree integration unit 19 calculates an integral value ∫D of the rotation fluctuation degree.
Step D4:
The output increase determination unit 15b determines whether the rotation fluctuation degree D is equal to or greater than a predetermined reference value D0.
[0057]
Step D5:
When D is less than D0 in step D4, that is, when the degree of fluctuation in rotation is small, the ignition timing determining unit 17 calculates the basic ignition timing α in the normal travel mode.
Step D6:
When D is equal to or greater than D0 in step D4, the output increase determination unit 15b determines whether or not the rotational fluctuation degree change D ′ is equal to or greater than a predetermined reference value D′ 0.
[0058]
Step D7:
When D ′ is greater than or equal to D′ 0 in step D6, the output increase determination unit 15b determines whether or not the integral value ∫D is greater than or equal to a predetermined reference value ∫D0.
Step D8:
When D ′ is less than D′ 0 in step D6, the output increase determination unit 15b determines whether the integral value ∫D is equal to or greater than a predetermined reference value ∫D0.
[0059]
Step D9:
When ∫D is greater than or equal to ∫D0 in step D7, the advance amount calculator 16b calculates the advance amount β.
Step D10:
When ∫D is less than ∫D0 in step D7, the advance amount calculation unit 16b calculates the advance amount γ.
[0060]
Step D11:
The ignition timing determination unit 17 calculates the final ignition timing (α + β) corrected by adding the advance amount β to the basic ignition timing α.
Step D12:
The ignition timing determination unit 17 calculates the final ignition timing (α + γ) corrected by adding the advance amount γ to the basic ignition timing α.
[0061]
Step D13:
When ∫D is greater than or equal to ∫D0 in step D8, the advance amount calculation unit 16b calculates the advance amount δ.
Step D14:
When ∫D is less than ∫D0 in step D8, the advance amount calculation unit 16b calculates the advance amount ε.
[0062]
Step D15:
The ignition timing determination unit 17 calculates the final ignition timing (α + δ) corrected by adding the advance amount δ to the basic ignition timing α.
Step D16
The ignition timing determination unit 17 calculates the final ignition timing (α + ε) corrected by adding the advance amount ε to the basic ignition timing α.
[0063]
Step D17:
Based on the final ignition timing α, (α + β), (α + γ), (α + δ) or (α + ε) calculated by the ignition timing determination unit 17, the ignition coil 11 is driven via the ignition circuit 8 to ignite the ignition plug of the engine. .
[0064]
【The invention's effect】
As described above, according to the present invention, the acceleration / deceleration operating state is detected based on the degree of crankshaft rotation fluctuation or the change thereof, and the correction of the increase / decrease in output is determined accordingly, In order to advance or retard the ignition timing accordingly, the acceleration / deceleration state can be detected without using a special throttle position detection sensor, and the ignition timing can be controlled accordingly. The driving feeling and fuel efficiency can be improved.
[0065]
Furthermore, in addition to the change in the degree of rotational fluctuation, by calculating the integrated value of the degree of rotational fluctuation so far and using it as the criteria for determining the driving state, for example, whether acceleration from idle during acceleration or acceleration from the normal running state The ignition timing can be accurately controlled in each acceleration state, and not only instantaneous acceleration / deceleration changes, but also improved driving feeling based on the driving state before the change occurs Can be achieved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a rotation detection signal according to the present invention.
FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a block diagram of another embodiment of the present invention.
FIG. 4 is a block diagram of still another embodiment of the present invention.
5 is a flowchart of the embodiment of FIGS. 3 and 4. FIG.
FIG. 6 is a block configuration diagram of still another embodiment of the present invention.
FIG. 7 is a block diagram of still another embodiment of the present invention.
8 is a flowchart of the embodiment of FIGS. 6 and 7. FIG.
FIG. 9 is a block configuration diagram of still another embodiment of the present invention.
FIG. 10 is a block configuration diagram of still another embodiment of the present invention.
11 is a flowchart of the embodiment of FIGS. 9 and 10. FIG.
FIG. 12 is a block configuration diagram of still another embodiment of the present invention.
FIG. 13 is a block diagram of still another embodiment of the present invention.
14 is a flowchart of the embodiment of FIGS. 12 and 13. FIG.
[Explanation of symbols]
1: crankshaft, 2: flywheel, 3: protrusion, 4: pickup coil,
5: ignition control device, 6: arithmetic circuit, 7: power supply circuit, 8: ignition circuit,
9: main switch, 10: battery, 11: ignition coil,
12: Rotational speed detection unit, 13: Rotational fluctuation degree detection unit,
14: rotation fluctuation degree change detection unit, 15: output correction determination unit,
16: output correction calculation unit, 17: ignition timing determination unit, 18: rotational acceleration detection unit,
19: Rotational fluctuation degree integration unit.

Claims (1)

A rotation speed detection unit that calculates a rotation speed from a rotation detection signal of the crankshaft, a rotation fluctuation degree detection unit that calculates a rotation fluctuation degree from the rotation detection signal of the crankshaft, and a rotation fluctuation degree that calculates a change in the rotation fluctuation degree A change detection unit; an output correction determination unit that determines whether to correct an increase or decrease in output based on the degree of rotation fluctuation and / or the change; and an ignition timing advance corresponding to the increase or decrease in output. An output correction calculation unit that calculates an angular amount or a retard amount, and an ignition timing determination unit that calculates an ignition timing based on the advance amount or retard amount of the ignition timing,
A flywheel mounted on the crankshaft is formed with a protrusion having a predetermined length, and includes a pickup coil that detects the protrusion, and the rotation of the crankshaft is detected by the pickup coil. The crankshaft period T based on the detection time t and the detection time interval of the protrusion detection unit of the rotation detection signal of the crankshaft is detected, and the ratio t / T of the protrusion detection time t with respect to the period T is rotated. Calculated as the degree of variation D,
The rotational fluctuation degree change detection unit is based on the rotational fluctuation degree t / T and the rotational fluctuation degree t ′ / T ′ of the next period as the change D ′ of the rotational fluctuation degree, and the difference t / T−t ′. / T ′ is calculated as a change D ′ in the rotational fluctuation degree,
A rotation fluctuation degree integration unit for calculating an integral value of the rotation fluctuation degree, and connecting the rotation fluctuation degree integration part to the output correction determination unit;
When the rotational fluctuation degree D is less than a predetermined reference value D0, the basic ignition timing α is calculated,
A control parameter is determined based on whether the rotational fluctuation degree D is equal to or greater than the reference value D0, the rotational fluctuation degree change D ′ and the integral value of the rotational fluctuation degree are greater than or equal to a predetermined value;
A final ignition timing is determined from the basic ignition timing α and the control parameter .

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