JP2012007577A - Capacitor charge/discharge type engine ignition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adopt overspeed limiting control which can reduce or alleviate vibration of an engine through the reduction in variations in engine rotation speed by repeatedly performing thinning misfire control in an overspeed region so as to match with high speed rotation performance of each engine.SOLUTION: The capacitor charge/discharge type engine ignition device is provided with a capacitor 7 for charge/discharge which is charged by positive half-wave output from a source coil 4, a switching element 8 for discharge which forces a charge of the capacitor 7 for charge/discharge to be discharged through an ignition coil 3 at ON time, an ignition timing control unit 14 which forces the switching element 8 for discharge to be turned on at the ignition timing according to the engine rotation speed by negative half-wave output of the source coil 4, and a misfire control unit 15 which reduces engine rotation speed through misfire at overspeed of the engine. The misfire control unit 15 repeats thinning misfire control for causing a misfire once or a plurality of N times which is a positive integer of less than M every time when the engine rotates by M times of a positive integer.

Description

  The present invention relates to a capacitor charging / discharging engine ignition device, and is configured to repeatedly perform a flash misfire control for misfire N times each time the engine rotates M times when the engine speed is in an overspeed state.

  A capacitor charging / discharging engine ignition device mounted on a small general-purpose engine such as a two-cycle engine charges a charging / discharging capacitor with a positive half-wave output of a source coil generated in synchronization with the rotation of the engine, and the negative of the source coil. With the half-wave output, the switching element is turned on at the ignition timing corresponding to the engine speed, and the engine is ignited by discharging the charge of the charge / discharge capacitor to the primary side of the ignition coil, and the engine speed is excessive. If it enters the area, the overspeed prevention control works to prevent the engine from overspeeding.

  In this overspeed prevention control, conventionally, when the engine speed is in an overspeed range, the ignition signal applied to the switching element is bypassed to prevent the charge / discharge capacitor from discharging and completely misfire. If the engine speed (prior art of Patent Document 1) exceeds the upper limit number of revolutions during normal operation of the engine, the ignition timing is gradually delayed from the upper limit number of revolutions to the misfire speed, and if the misfire speed is reached, it is completely Some of them are misfired (paragraph 0004 of Patent Document 1).

JP 05-001651 A

  In the conventional overspeed prevention control, there is a difference between the complete misfire immediately when the engine speed increases to the overspeed range or the complete misfire through the control that delays the ignition timing. In any case, since the engine is completely misfired every period while the engine speed is in the overspeed range, the engine speed varies greatly between before and after the complete misfire, and the engine vibration is extremely high. There are increasing drawbacks. For this reason, in the conventional engine ignition device, it is difficult to employ over-rotation prevention control that matches the high-speed rotation performance of each engine.

  In view of such a conventional problem, the present invention can reduce or reduce engine vibration by reducing variation in engine speed by repeatedly performing thinning-out misfire control in an overspeed region, and each engine has high speed rotation performance. An object of the present invention is to provide a capacitor charging / discharging engine ignition device that can employ over-rotation prevention control matched to the above.

  The present invention includes a charge / discharge capacitor charged by a positive half-wave output from a source coil, a discharge switching element that discharges the charge of the charge / discharge capacitor through an ignition coil when turned on, and a negative of the source coil. A capacitor charging unit comprising ignition timing control means for turning on the discharge switching element at an ignition timing corresponding to the engine speed by half-wave output of the engine, and misfire control means for reducing the engine speed by causing the engine to misfire when the engine over-rotates. In the discharge-type engine ignition device, the misfire control means repeats thinning-out misfire control that causes one or more N integers of a positive integer less than M to be misfired every time the engine rotates a plurality of M times that is a positive integer. It is a thing.

  The misfire control means is stored in the storage unit while counting the number of rotations of the engine M times, a storage unit storing the N number of misfires, and the count unit counting M times. A thinning-out misfire control unit that misfires N times may be provided. The misfire control means defines an over-rotation region in which the thin-out misfire control is performed until the engine speed exceeds the misfire start speed and returns to the misfire end speed or less, and the misfire end speed is greater than the misfire start speed. It is desirable that

  During the misfire control, the misfire control means may perform the misfire control by turning on the discharge switching element and at the same time prevent overcharging of the charge / discharge capacitor. The misfire control means may perform MN ignition control first out of M times, and then N times misfire control. The misfire control means turns on the discharge switching element from the last ignition control of the MN ignition control to before the positive half-wave output is generated in the source coil at the Nth rotation of the engine. You may make it make it.

  According to the present invention, by repeating the thinning-out misfire control in the overspeed region, it is possible to reduce or reduce engine vibration by reducing variations in the engine speed, and to control overspeed that matches the high speed performance of each engine. There is an advantage that can be adopted.

1 is a circuit diagram of a capacitor charging / discharging engine ignition device showing a first embodiment of the present invention. It is the same block diagram. It is the same timing chart. It is explanatory drawing of the timing chart. It is explanatory drawing of the engine speed. It is the same flowchart. It is a timing chart which shows the 2nd Embodiment of this invention. It is explanatory drawing of the engine speed which shows the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 6 illustrate a first embodiment of the present invention. FIG. 1 shows a capacitor charging / discharging engine ignition device. The engine ignition device includes a magnet generator 1 driven by an engine, an ignition coil 3 connected to an ignition plug 2, and a magnet generator 1. The charge / discharge capacitor 7 charged through the diodes 5 and 6 by the positive half-wave output Vp (see FIG. 3A) generated in the source coil 4 and the charge of the charge / discharge capacitor 7 at the time of turning on the ignition coil 3 and the discharge switching element 8 for bypassing the positive half-wave output Vp generated in the source coil 4 during the thin-out misfire control, and the negative half-wave outputs Vn1, Vn2 ( 3A), the power supply circuit 10 charged via the diode 9, the first waveform shaping circuit 11 for shaping the positive half-wave output Vp of the source coil 4, and the source A second waveform shaping circuit 12 for waveform-shaping the negative half wave output Vn1, Vn2 of-yl 4, and a microcomputer 13 which operates by the power supply voltage Vcc of the power supply circuit 10.

  The waveform shaping circuits 11 and 12 have first and second switching elements 11a and 12a, and the half-wave outputs Vp, Vn1 and Vn2 of the source coil 4 are pulsed by turning on and off the first and second switching elements 11a and 12a. Waveforms are formed into vp, vn1, and vn2 (see FIGS. 3B and 3C).

  The microcomputer 13 includes a RAM, a ROM, a CPU, and the like. As shown in FIG. 2, an ignition signal is sent to the discharge switching element 8 at an ignition timing corresponding to the engine speed based on the negative half-wave output Vn1 of the source coil 4. When the engine timing is in the overspeed range OT (see FIG. 5) and the ignition timing control means 14 outputs (see FIG. 3 (E)), the engine timing is less than M times each time the engine rotates a plurality of M times. And misfire control means 15 that repeats thinning misfire control that causes one or more N misfires.

  The ignition timing control means 14 includes a rotation speed detection unit 16 that detects the engine rotation speed based on the rotation period T between the pulses vn1 before and after the negative half-wave output Vn1, and the engine rotation speed detected by the rotation speed detection unit 16. An ignition timing calculation unit 17 that calculates the corresponding ignition timing, and an ignition control unit that turns on the discharge switching element 8 by issuing a short ignition signal (see FIG. 3E) when the pulse vn1 rises according to the ignition timing. 18. When the discharge switching element 8 is turned on by the ignition signal, the charge of the charge / discharge capacitor 7 is discharged as shown in FIG. 3D, and the engine is ignited by the spark generated in the spark plug 2.

  The misfire control means 15 is configured to repeat the thin-out misfire control at a ratio of N / M that causes N misfires every time the engine rotates M times when the engine is in the overspeed region OT. M is a plurality that is a positive integer, and N is one or more that is a positive integer less than M. In this embodiment, since the misfire control is performed twice every time the engine rotates three times, M = 3 and N = 2.

  The misfire control means 15 includes a rotation speed detection unit 16, an overspeed region determination unit 19 that determines whether or not the engine speed detected by the rotation number detection unit 16 is in the overspeed region OT, and an overspeed region. A counting unit 20 that repeatedly counts the number of rotations of the engine M times in OT, a storage unit 21 that stores N number of misfires while the engine rotates M times, and a counting unit 20 that rotates M times of the engine Each time the engine is counted, when the engine speed is the first (MN), an ignition signal is output according to the engine speed to ignite the engine, and then the first time until the engine rotates N times. And a thinning-out misfire control unit 22 that performs the N misfire control by continuing the on-state of the discharge switching element 8 by outputting the ignition signal of the above.

  Each ignition signal is output when the pulse vn1 of the negative half-wave output Vn1 of the source coil 4 rises, and at the time of thinning-out misfire control, the engine rotates N times from the first ignition control as shown in FIG. Thus, the ignition signal at the first ignition is output as it is until the positive half-wave output Vp is generated in the source coil 4 at the M-th rotation of the engine from the transition to the thin-out misfire control. Yes.

  Therefore, the discharge switching element 8 remains on during the thin-out misfire control after the first ignition, and even if the positive half-wave output Vp is generated in the source coil 4, the positive half-wave output Vp is discharged. Therefore, the charging / discharging capacitor 7 is not charged and remains misfired while the engine rotates twice after the first ignition.

  As shown in FIG. 5, a misfire start rotation speed N1 and a misfire end rotation speed (ignition return rotation speed) N2 are set in the overspeed area determination unit 19, and the engine speed detected by the rotation speed detection unit 16. The over-rotation region OT is a rotation region from when the misfire start rotational speed N1 is increased to a value equal to or higher than the misfire start rotational speed N1 and then to the misfire end rotational speed N2. The misfire start rotation speed N1 is set near the upper limit rotation speed in the normal rotation region, and the misfire end rotation speed N2 is set slightly higher than the misfire start rotation speed N1. Incidentally, in this embodiment, the misfire start rotational speed N1 is 12000 r / min, and the misfire end rotational speed N2 is 12,500 r / min.

  This engine ignition device operates as follows. When the engine speed reaches the overspeed range OT, the thinning misfire control is repeated at a rate of N / M. That is, during engine rotation, the negative half-wave output Vn1, the positive half-wave output Vp, and the negative half-wave output Vn2 are repeatedly applied to the source coil 4 as shown in FIG. appear. When the positive half-wave output Vp is generated in the source coil 4, the charge / discharge capacitor 8 is charged via the diodes 5 and 6. When negative half-wave outputs Vn1 and Vn2 are generated in the source coil 4, the power supply circuit 10 is charged via the diode 9, and the microcomputer 13 becomes operable by the rise of the power supply voltage Vcc after one revolution of the engine. .

  The positive half-wave output Vp of the source coil 4 is turned on / off by the first switching element 11a of the first waveform shaping circuit 11, and the negative half-wave outputs Vn1 and Vn2 of the source coil 4 are the second waveform shaping circuit 12 of the second waveform shaping circuit 12. The waveforms are shaped into pulses vp, vn1, and vn2 shown in FIGS. 3B and 3C, respectively, by turning on and off the two switching elements 12a.

  During engine rotation, the ignition timing control means 14 outputs an ignition signal at an ignition timing corresponding to the engine speed, turns on the discharge switching element 8, and ignites at a timing suitable for the engine speed. That is, while the engine is rotating, the rotation speed detection unit 16 constantly detects the engine rotation speed, and each time the engine rotates once, the rotation speed detection unit 16 calculates the rotation period T between the preceding and following pulses vn1 and rotates. Detect numbers. The ignition timing calculation unit 17 reads the ignition timing data in the ignition timing control table and calculates the ignition timing according to the engine speed at that time. Therefore, the ignition control unit 18 outputs an ignition signal when the pulse vn1 rises. Then, the discharge switching element 8 is turned on.

  When the discharge switching element 8 is turned on, the charge of the charge / discharge capacitor 7 is discharged through the discharge switching element 8 and the primary side of the ignition coil 3, and a high voltage is generated on the secondary side of the ignition coil 3. As a result, a spark is generated in the spark plug 2 to ignite the engine.

  Accordingly, during normal engine rotation, the ignition timing control means 14 outputs an ignition signal in synchronization with the engine speed as shown in FIG. 3E, and the charge / discharge capacitor 7 is shown in FIG. 3D. The engine is ignited by repeating charging and discharging.

  If the engine speed increases beyond the normal rotation range to the over-rotation range OT during the operation of the engine due to rapid load reduction or the like, the microcomputer 13 performs the thin-out misfire control according to the flowchart shown in FIG. That is, while the engine is operating, the engine speed detected by the speed detector 16 is read (step S1), and it is determined whether there is a flag that has shifted to the thin-out misfire control (step S2).

  If it is before the transition to the thinning-out misfire control, it is determined whether or not the thinning-out misfire control is started based on whether or not the engine speed is equal to or higher than the misfire starting rotational speed N1 (step S3). If the engine rotation speed at that time is less than the misfire start rotation speed N1 (= 12000 r / min), the engine rotation speed is in the normal rotation range, so a short ignition signal is generated at the rise of the pulse vn1 of the negative half-wave output Vn1. The normal ignition control for outputting and igniting at the ignition timing corresponding to the engine speed is continued (step S4).

  If the engine speed is equal to or greater than the misfire start speed N1 (step S3), after setting a flag for shifting to the thin-out misfire control (step S5), it is determined whether or not the engine speed is the first of the M times. Judgment is made (step S6), and if it is the first time, the count of 1 is added (step S7), and then ignition is performed at the rise of the pulse vn1 of the negative half-wave output Vn1 as shown in FIGS. Output a signal.

  Since the discharge switching element 8 is turned on by this ignition signal, the charge of the charge / discharge capacitor 7 is discharged for the first time in three rotations of the engine, and the engine is ignited at the ignition timing corresponding to the rotation speed at that time. Thereafter, thinning-out misfire control is performed (step S8).

  During this thinning-out misfire control, the ignition signal remains output until the engine has rotated N times as shown in FIG. 4 (E), so even if a positive half-wave output Vp is generated in the source coil 4, the positive signal Since the half-wave output Vp flows through the diodes 5 and 6 and the discharging switching element 8, the charging / discharging capacitor 7 is not charged as shown in FIG.

  If the number of engine revolutions after the shift to the thinning-out misfire control becomes the second time, the flag that has already shifted to the thinning-out misfire control is set (step S2), so the engine speed is set to the misfire end rotational speed N2 (= 12,500 r / min) It is determined whether or not to terminate the misfire control depending on whether or not (step S9). If the second engine speed is greater than the misfire end speed N2, the process proceeds to step S10 through step S6, and it is determined whether the number of rotations at that time is the third (Mth). Since the number of rotations at this time is the second, the count is incremented by 1 (step S11), and the process returns to the return while continuing the thin-out misfire control (step S12).

  If the engine rotation number in the thinning-out misfire control is the third time (step S10), the number count is reset and returned to the first time (step S13), and the Nth misfire is completed as shown in FIG. After the discharge switching element 8 is turned on until the next positive half-wave output Vp is generated, output of the ignition signal is stopped (step S14).

  When the output of the ignition signal is stopped, the discharge switching element 8 is turned off, and the positive half-wave output Vp generated in the source coil 4 thereafter is charged for the next ignition as shown in FIG. The discharging capacitor 7 is charged.

  If the number of engine revolutions in the thinning-out misfire control is the fourth time, it is determined through steps S1, S2 and S9 that it is the first of the next three revolutions (step S6), and the count is incremented by 1 (step S7). In the same manner as described above, an ignition signal is output at the rising edge of the pulse vn1 of the negative half-wave output Vn1, and the engine is ignited by discharging the charge / discharge capacitor 7 by turning on the discharge switching element 8 (step). S8). The same control is repeated until the number of engine revolutions is reduced to the misfire end rotation speed N2 or less, and thinning-out misfire control is repeated in which misfire is performed twice every three rotations.

  If the engine speed decreases to the misfire end speed N2 or less as shown in FIG. 5 while repeating the thinning-out misfire control (step S9), the flag that has shifted to the thin-out misfire control is turned off and the misfire control is finished (step S15). ), Returning to normal ignition control (step S4).

  In this way, when the engine speed is in the over-rotation region OT, it is compared with the conventional misfire control that completely misfires every cycle by repeatedly performing the thin-out misfire control that misfires N times every time the engine rotates M times. Thus, variations in engine rotation between the over-rotation region OT and the normal rotation regions before and after the over-rotation region OT can be reduced, and engine vibration that has occurred due to the variation in rotation can be reduced or alleviated. Therefore, there is an advantage that it is possible to employ over-rotation prevention control that matches the high-speed rotation performance of each engine.

  Further, in determining the over-rotation region OT from when the engine speed increases to the misfire start speed N1 or more until it decreases to the misfire end speed N2 or less, the misfire end speed N2 is set to be greater than the misfire start speed N1. Therefore, even if there is a slight delay in the decrease in engine speed with respect to the thinning-out misfire control, it is possible to prevent the engine speed from falling too much due to the thinning-out misfire control, and the engine speed near the upper limit of the normal rotation range. Can be stabilized.

  Further, since the discharge switching element 8 is turned on during the thinning-out misfire control, misfire control for preventing ignition of the engine can be performed by turning on the discharge switching element 8, and at the same time, The generated positive half-wave output Vp can be bypassed through the discharging switching element 8, thereby preventing overcharging of the charging / discharging capacitor 7.

  In addition, since the first ignition is made during the three revolutions of the engine and the second and third two revolutions are misfired, the discharge switching element 8 is turned on / off to perform thinning-out misfire control and charge / discharge. It is possible to easily prevent the capacitor 7 from being overcharged. That is, when the first and second of the three rotations of the engine are misfired and the third ignition is performed, thinning-out misfire due to on / off of the discharge switching element 8 cannot be performed, and the charge / discharge capacitor 7 In order to prevent overcharge, the configuration becomes very complicated, for example, a bypass element is required in addition to the discharge switching element 8, but such a problem can be solved.

  FIG. 7 illustrates a second embodiment of the present invention. This embodiment shows thinning-out misfire control when misfire is made twice (N times) every 5 revolutions (M times) of the engine. In this case, after the engine speed increases to the overspeed range OT and shifts to the thin-out misfire control, as shown in FIG. 7B, the first and second of the five engine revolutions are normal. The ignition control is performed by outputting a similar short ignition signal, and the same control as in the first embodiment is performed for the third to fifth times. As a result, as shown in FIG. 7A, it is possible to perform the misfire control while the first three rotations are ignited and the subsequent two rotations are misfired as shown in FIG. 7A.

  Therefore, even when the thinning-out misfire control is performed to misfire N times each time the engine rotates M times, the M times and N times may be appropriately determined in consideration of the high-speed rotation characteristics of the engine. In addition, when the engine is misfired N times during M rotations, if the number of (MN) times becomes two or more times, one or more times less than (MN) times are normal. The ignition control may be performed in the same manner as in the first embodiment for N times from (M−N) times to M times.

  FIG. 8 illustrates a third embodiment of the present invention. This embodiment illustrates a case where the misfire start rotation speed N1 is set near the upper limit value of the normal rotation region, and the misfire end rotation speed N2 is set slightly lower than the misfire start rotation speed N1. In this case, the over-rotation region OT is from the time when the engine speed exceeds the misfire start speed N1 to the time when the engine speed decreases to the misfire end speed N2 or less.

  After the engine speed increases to the misfire start speed N1 or higher, the thin-out misfire control is performed at a rate of N / M, and the misfire end when the engine speed is lower than the misfire start speed N1 by the thin-out misfire control. If the thin-out misfire control is terminated when the rotational speed falls below N2, the engine rotational speed can be prevented from unexpectedly increasing after returning to the normal ignition control.

  As mentioned above, although each embodiment of this invention was explained in full detail, this invention is not limited to each embodiment. For example, in the embodiment, when ignition is performed during the thinning-out misfire control, in order to avoid a rapid decrease in horsepower, the engine speed at that time or a timing suitable for the engine speed near the upper limit of the normal rotation range should be set. Is desirable. However, one or a plurality of ignitions during the thinning-out misfire control may be performed by retarding compared to the normal ignition timing.

  The misfire start rotational speed N1 and the misfire end rotational speed N2 may be set substantially the same. In the embodiment, the software control method is adopted, but a hardware control method may be adopted.

  M times and N times are arbitrary numbers, and are not limited to the number of times exemplified in the embodiment. However, M times is a positive integer, for example, 2 to 7 times, preferably 3 to 5 times, because the engine speed in the overspeed state is returned to high speed rotation near the upper limit of the normal rotation range by thinning-out misfire control. Degree, N is a positive integer less than M, 1 or more, for example 1 to 6 times, preferably about 2 to 4 times, and the ratio of decimation misfire is from 1/3 to half or more Is appropriate.

3 ignition coil 4 source coil 7 charge / discharge capacitor 8 discharge switching element 14 ignition timing control means 15 misfire control means 20 count part 21 storage part 22 thinning-out misfire control part N1 misfire start speed N2 misfire end speed OT overspeed area

Claims (6)

A charging / discharging capacitor charged by a positive half-wave output from the source coil, a discharging switching element for discharging the charge of the charging / discharging capacitor through an ignition coil when turned on, and a negative half-wave output of the source coil A charge / discharge engine ignition device comprising: an ignition timing control means for turning on the discharge switching element at an ignition timing according to the engine speed; and a misfire control means for reducing the engine speed by causing the engine to misfire when the engine over-rotates. In the apparatus, each time the engine rotates a plurality of M times that are positive integers, the misfire control means repeats the skip misfire control during one or a plurality of N times that are positive integers less than M. Capacitor charge / discharge engine ignition device. The misfire control means is stored in the storage unit while counting the number of rotations of the engine M times, a storage unit storing the N number of misfires, and the count unit counting M times. The capacitor charge / discharge engine ignition device according to claim 1, further comprising a thinning-out misfire control unit that misfires N times. The misfire control means defines an over-rotation region in which the thin-out misfire control is performed until the engine speed exceeds the misfire start speed and returns to the misfire end speed or less, and the misfire end speed is greater than the misfire start speed. The capacitor charging / discharging engine ignition device according to claim 1 or 2, wherein 4. The misfire control means according to claim 1, wherein during the misfire control, the discharge switching element is turned on to perform the misfire control and simultaneously prevent overcharging of the charge / discharge capacitor. The capacitor charging / discharging engine ignition device according to any one of the above. 5. The misfire control means according to any one of claims 1 to 4, wherein the misfire control means performs MN ignition control first in M times, and then performs N misfire control thereafter. Capacitor charge / discharge engine ignition system. The misfire control means turns on the discharge switching element from the last ignition control of the MN ignition control to before the positive half-wave output is generated in the source coil at the Nth rotation of the engine. 6. The capacitor charging / discharging engine ignition device according to claim 5, wherein the capacitor ignition / discharge engine ignition device is provided.

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