JP5986063B2 - General-purpose engine ignition control device - Google Patents

Description

  The present invention relates to a general-purpose engine ignition control device.

  Many 4-cycle general-purpose engines are ignited not only in the compression stroke but also in the exhaust stroke of the intake, compression, explosion, and exhaust strokes for the purpose of simplifying the apparatus. Ignition in the compression stroke is ignition according to the combustion cycle, and the air-fuel mixture is combusted by the ignition, so it is called “regular ignition”, but ignition in the exhaust stroke follows the combustion cycle. Since the air-fuel mixture is not combusted by the ignition, not the ignition, this is a useless ignition called “abandoned fire”.

  Therefore, a general-purpose engine that generates abandoned fire has the disadvantage of shortening the life of the spark plug by the amount of useless ignition. Therefore, in order to eliminate such inconvenience, there is a technique in which it is determined whether the ignition is performed in the compression stroke or the exhaust stroke, and only the normal ignition in the compression stroke is performed based on the determination result. It has been proposed (for example, Patent Document 1).

  The technology described in Patent Document 1 calculates the average engine speed of a general-purpose engine over a predetermined time, stops ignition (cuts) at least once in either the compression stroke or the exhaust stroke, and then stops the ignition. It is determined whether or not the stroke in which ignition is stopped is the compression stroke by determining how much the engine rotation speed of the engine has decreased with respect to the average engine rotation speed (decrease degree). Specifically, when the difference between the average engine speed and the engine speed after the ignition is stopped exceeds a predetermined value, it is determined that the stopped ignition is performed in the compression stroke. Thus, if it is possible to determine the stroke in which the ignition is stopped, only the regular ignition in the compression stroke can be performed, so that it is possible to prevent the life of the spark plug from being shortened due to abandoned fire.

Japanese Patent No. 4801184

  However, for example, when an event such as unauthorized combustion occurs before and after the ignition cut, the degree of decrease in the engine speed after the ignition cut may change. Therefore, as in the technique described in Patent Document 1, it is not possible to accurately determine the stroke when the degree of decrease in the engine speed changes only by comparing the degree of decrease in the engine speed after the ignition cut with a predetermined value. There was a case.

  Accordingly, an object of the present invention is to provide an ignition control device for a general-purpose engine that can solve only the above-described problems and can perform only normal ignition in the compression stroke by accurately determining the compression stroke and the exhaust stroke. is there.

  In order to achieve the above object, according to claim 1, in the ignition control device for a general-purpose engine that controls the ignition signal so that ignition is performed in two strokes of a compression stroke and an exhaust stroke of four cycles, An engine speed detecting means for detecting an engine speed of a general-purpose engine; an average engine speed calculating means for calculating an average engine speed over a predetermined time based on the detected engine speed; First ignition stop control means for controlling the ignition signal so as to stop ignition at least once in any one of the steps, and at least ignition in a stroke different from the stroke in which the ignition was stopped by the first ignition stop control means Second ignition stop control means for controlling the ignition signal so as to stop once, the calculated average engine speed and the first ignition stop control means. The first difference calculating means for calculating a difference from the engine speed detected after the ignition is stopped at least once, and the ignition is performed at least once by the calculated average engine speed and the second ignition stop control means. Comparing the difference calculated by the second difference calculating means with the difference calculated by the first difference calculating means and the difference calculated by the second difference calculating means; A stroke discriminating unit for discriminating whether the stroke in which the ignition is stopped by the first ignition stop control unit or the stroke in which the ignition is stopped by the second ignition stop control unit is the compression stroke; And an ignition control means for controlling an ignition signal so that ignition is performed in the compression stroke.

  In the ignition control device for a general-purpose engine according to claim 2, the stroke determination unit is configured such that the difference calculated by the first difference calculation unit is larger than the difference calculated by the second difference calculation unit. The stroke in which the ignition is stopped by the first ignition stop control means is determined as the compression stroke.

  In the ignition control device for a general-purpose engine according to claim 3, the stroke determination means compares the difference calculated by the first difference calculation means with the difference calculated by the second difference calculation means. And a process in which the ignition is stopped by the first ignition stop control means and a process in which the ignition is stopped by the second ignition stop control means is based on the comparison result performed a plurality of times. It was configured to determine whether it was a compression stroke.

  The ignition control device for a general-purpose engine according to claim 4 includes a load detection sensor for detecting a load of the general-purpose engine, and an ignition signal so that ignition is performed in the compression stroke by the ignition control means. After the above control is started, the ignition voltage used for ignition in the exhaust stroke is used as the power supply voltage of the load detection sensor.

  In the ignition control device for a general-purpose engine according to claim 1, first ignition stop control means for controlling an ignition signal so as to stop ignition at least once in any one of a compression stroke and an exhaust stroke. And a second ignition stop control means for controlling the ignition signal so as to stop the ignition at least once in a stroke different from the stroke where the ignition is stopped by the first ignition stop control means, and the average engine speed of the general-purpose engine And the difference between the engine speed detected after the ignition is stopped at least once by the first ignition stop control means, the average engine speed of the general-purpose engine and after the ignition is stopped at least once by the second ignition stop control means Comparing the difference with the detected engine speed, the stroke in which the ignition is stopped by the first ignition stop control means and the ignition by the second ignition stop control means Since it is configured to determine which one of the stopped strokes is the compression stroke, and to control the ignition signal so that ignition is performed in the determined compression stroke, the first ignition stop control means by comparing the difference Therefore, it is possible to accurately determine which of the stroke in which the ignition is stopped and the stroke in which the ignition is stopped by the second ignition stop control means, and only the normal ignition in the compression stroke can be performed.

  In the ignition control device for a general-purpose engine according to claim 2, when the difference calculated by the first difference calculation unit is larger than the difference calculated by the second difference calculation unit, the stroke determination unit stops the first ignition Since the stroke in which the ignition is stopped by the control means is determined to be the compression stroke, in addition to the above effects, it becomes possible to more accurately determine the compression stroke and the exhaust stroke, and only normal ignition in the compression stroke can be performed. It can be done reliably.

  In the ignition control device for a general-purpose engine according to claim 3, the stroke determination unit performs the comparison between the difference calculated by the first difference calculation unit and the difference calculated by the second difference calculation unit a plurality of times. Further, based on the comparison result performed a plurality of times, it is configured to determine which one of the stroke in which the ignition is stopped by the first ignition stop control means and the stroke in which the ignition is stopped by the second ignition stop control means. Therefore, in addition to the effects described above, the compression stroke and the exhaust stroke can be determined with higher accuracy, and only normal ignition in the compression stroke can be performed more reliably.

  The ignition control device for a general-purpose engine according to claim 4 includes a load detection sensor for detecting the load of the general-purpose engine, and control of the ignition signal is started so that ignition is performed in the compression stroke by the ignition control means. After that, since the ignition voltage used for ignition in the exhaust stroke is configured to be used as the power supply voltage of the load detection sensor, in addition to the above effect, for the ignition in the exhaust stroke that is no longer used Effective use of the ignition voltage can be achieved. In order to secure the power supply voltage of the load detection sensor, for example, it is not necessary to strengthen the magnetic force of the magnet of the flywheel, to change the specifications and configuration of the winding and the iron core, or to prepare a separate power supply etc. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall ignition control device for a general-purpose engine according to a first embodiment of the present invention. It is a flowchart which shows operation | movement of the apparatus shown in FIG. FIG. 3 is a sub-routine flow chart showing a process determination process of FIG. 2. FIG. FIG. 4 is an explanatory diagram for explaining a process determination method of FIG. 3. It is explanatory drawing for demonstrating the waveform of the electromotive force which generate | occur | produced in the exciter coil of the ignition control apparatus of the general purpose engine which concerns on 2nd Example of this invention. It is a circuit block diagram of an ignition device provided with the exciter coil shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments for implementing an ignition control device for a general-purpose engine according to the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an overall ignition control device for a general-purpose engine according to an embodiment of the present invention.

  In FIG. 1, reference numeral 10 indicates a general-purpose engine (a general-purpose internal combustion engine; hereinafter simply referred to as “engine”). The engine 10 is an air-cooled four-cycle single-cylinder OHV engine that uses gasoline as fuel, and has an engine displacement of, for example, about 440 cc.

  A single piston 14 is accommodated in a cylinder (cylinder) formed inside the cylinder block 12 of the engine 10 so as to be capable of reciprocating. A cylinder head 16 is attached to an upper portion of the cylinder block 12, and a combustion chamber 18 formed at a position facing the top of the piston 14, and an intake port 20 and an exhaust port 22 communicating with the combustion chamber 18 are provided. . An intake valve 24 is provided near the intake port 20, and an exhaust valve 26 is provided near the exhaust port 22.

  A crankcase 30 is attached to the lower part of the cylinder block 12, and a crankshaft 32 is rotatably accommodated therein. The crankshaft 32 is connected to the lower part of the piston 14 via a connecting rod 34. A load 36 is connected to one end of the crankshaft 32, and the engine 10 outputs power to the load 36.

  A flywheel 38, a cooling fan 40, and a start recoil starter 42 are attached to the other end of the crankshaft 32. A power coil (power generation coil) 44 is attached to the crankcase 30 inside the flywheel 38, and a magnet (permanent magnet) 46 is attached to the back surface of the flywheel 38. The power coil 44 and the magnet 46 constitute a multipolar generator and generate an output synchronized with the rotation of the crankshaft 32.

  An exciter coil 48 is attached to the crankcase 30 outside the flywheel 38, and a magnet (permanent magnet) 50 is attached to the surface of the flywheel 38. The exciter coil 48 generates an output every time the magnet 50 passes.

  A camshaft 52 is rotatably accommodated in the crankcase 30 in parallel with the axis of the crankshaft 32 and is connected to and driven by the crankshaft 32 via a gear mechanism 54. The cam shaft 52 includes an intake side cam 52a and an exhaust side cam 52b, and drives the intake valve 24 and the exhaust valve 26 via push rods and rocker arms 56 and 58 (not shown).

  A carburetor 60 is connected to the intake port 20. The carburetor 60 is integrally provided with an intake passage 62, a motor case 64, and a carburetor assembly 66. A throttle valve 68 and a choke valve 70 are disposed in the intake passage 62.

  The motor case 64 houses a throttle electric motor 72 that drives the throttle valve 68 and a choke electric motor 74 that drives the choke valve 70. The throttle electric motor 72 and the choke electric motor 74 are stepping motors.

  The carburetor assembly 66 receives fuel supplied from a fuel tank (not shown), injects an amount of fuel corresponding to the opening degree of the throttle valve 68 and the choke valve 70, and mixes it with the intake air flowing through the intake passage 62 to generate an air-fuel mixture. To do.

  The generated air-fuel mixture is sucked into the combustion chamber 18 through the intake port 20 and the intake valve 24, and is ignited and burned through an ignition device including an ignition plug and an ignition coil. Exhaust generated by the combustion is discharged to the outside of the engine 10 through an exhaust valve 26, an exhaust port 22, a silencer (not shown), and the like.

  A throttle opening sensor 76 is disposed in the vicinity of the throttle valve 68, outputs a signal corresponding to the opening of the throttle valve 68, and a temperature sensor 78 such as a thermistor is disposed at an appropriate position of the cylinder block 12. An output indicating the temperature of the engine 10 is produced. An absolute pressure sensor 80 is disposed downstream of the throttle valve 68 in the intake port 20 and outputs a signal proportional to the intake port internal pressure (engine load).

  The outputs of the throttle opening sensor 76, the temperature sensor 78, the absolute pressure sensor 80, the power coil 44 and the exciter coil 48 are sent to an electronic control unit (hereinafter referred to as “ECU”) 84. The ECU 84 includes a microcomputer including a CPU, a ROM, a memory, an input / output circuit, and the like.

  In the ECU 84, the output (AC power) of the power coil 44 is input to the bridge circuit, is full-wave rectified and converted into a DC power source, and is used as an operating power source for the ECU 84 and the electric motor 72 for the throttle. Converted to a pulse signal. The output of the exciter coil 48 is used as an ignition signal for the ignition device. That is, the exciter coil 48 generates an ignition signal for each rotation of the crankshaft.

  In the ECU 84, the CPU detects the engine speed based on the converted pulse signal, and based on the detected engine speed, the output of the throttle opening sensor 76 and the temperature sensor 78, the throttle electric motor 72 and the choke electric motor 74. And controlling ignition through an ignition device. In the ECU 84, the CPU corrects the ignition timing based on the output of the absolute pressure sensor 86 and controls the engine 10 to ignite at an appropriate timing.

  Hereinafter, the ignition control will be specifically described.

  FIG. 2 is a flowchart showing the operation of the ignition control apparatus according to the embodiment of the present invention. The illustrated program is executed when the recoil starter 42 is operated, the power coil 44 starts generating electricity by the rotation of the flywheel 38, and the ECU 84 is activated.

  As will be described below, a stroke determination process is executed in S10.

  FIG. 3 is a sub-routine flowchart showing the stroke determination process.

  It is determined whether or not the engine speed NE detected in S100 exceeds the complete explosion speed. The complete explosion speed is a speed at which the recoil starter 42 can determine that the engine start has been completed, and is set to 800 rpm, for example. If the engine speed NE exceeds the complete explosion speed, the process proceeds to S102.

  In S102, it is determined whether or not the engine 10 is in an idle state. Specifically, it is determined whether or not the detected engine speed NE is between 1400 rpm and 1600 rpm as the idle speed. If it is determined that the engine 10 is in the idle state, the process proceeds to S104.

  In S104, an average engine speed (average engine speed) NEave is calculated. Specifically, the average engine speed NEave is calculated from a simple average of a plurality of engine engine speeds NE detected over a predetermined time (for example, 1 sec).

  Next, in S106, the calculated average rotational speed NEave is stored in the memory.

  Next, in S108, the ignition signal is used to cut (stop) the ignition once in one of the two strokes of the compression stroke and the exhaust stroke (hereinafter referred to as "A stroke" in the description of this flow chart). To control. Ignition is alternately performed in the compression stroke and the exhaust stroke every time the crankshaft 32 makes one rotation. Normally, unless any stroke discrimination is performed, whether the ignition is performed in the compression stroke or in the exhaust stroke. It is not possible to determine if it was done. Therefore, the A stroke is arbitrarily selected, and it is not known at this time whether the A stroke is a compression stroke or an exhaust stroke.

  The ignition cut is performed by controlling so as not to output an ignition command to an ignition coil with respect to an arbitrary ignition signal among ignition signals sequentially generated as the crankshaft 32 rotates. Instead of executing the ignition cut only once, it is also possible to execute a plurality of ignition cuts every other time.

  Next, in S110, the engine speed NEmfA after the ignition cut in the A stroke is detected. The engine speed NEmfA is an engine speed detected after a time set according to the average speed NEave has elapsed since the ignition cut was executed.

  Next, the routine proceeds to S112, where a rotational fluctuation difference ΔNEA indicating a fluctuation (degree of decrease) in the engine speed NE before and after the ignition cut is calculated. The rotational fluctuation difference ΔNEA is calculated by subtracting the engine rotational speed NEmfA after ignition cut from the average rotational speed NEave.

  Next, in S114, an ignition signal is generated so that the ignition is cut once in a stroke different from the A stroke (hereinafter referred to as "B stroke" in the description of the flow chart) of the two strokes of the compression stroke and the exhaust stroke. Control. Specifically, control is performed so as not to output an ignition command to the ignition coil for an arbitrary ignition signal among the ignition signals generated in the B stroke.

  Next, in S116, the engine speed NEmfB after the ignition cut in the B stroke is detected by the same process as in S110.

  Next, the routine proceeds to S118, where a rotation fluctuation difference ΔNEB indicating a fluctuation in the engine speed NEmfB before and after the ignition cut in the B stroke is calculated. The rotational fluctuation difference ΔNEB is calculated by subtracting the engine speed NEmfB after the ignition cut from the average speed NEave.

  Next, the process proceeds to S120, and a stroke determination is performed to determine whether the A stroke and the B stroke are the compression stroke or the exhaust stroke, respectively, by comparing the rotational fluctuation differences ΔNEA and ΔNEB.

  FIG. 4 is an explanatory diagram for explaining a method of stroke determination.

  FIG. 4A shows an idle state after the engine is started. As shown in the figure, based on the voltage waveform of the exciter coil 48 generated each time the crankshaft 32 makes one rotation, normal ignition near the end of the compression stroke and abandonment fire near the end of the exhaust stroke are executed. The engine speed NE increases immediately after the normal ignition, but does not increase immediately after the discarded fire but decreases until the next normal ignition.

  FIG. 4B shows the rotational speed fluctuation when ignition cut is executed in the compression stroke and the exhaust stroke. When ignition cut is executed in the exhaust stroke, there is no significant change in the engine speed NE after that. However, when ignition cut is executed in the compression stroke, no explosion occurs and the engine goes to the explosion stroke. The number NE decreases (in the figure, the engine speed NE after ignition cut is decreased by ΔNE with respect to the average engine speed NEave, that is, the rotational fluctuation difference is ΔNE). Therefore, it is possible to determine whether the stroke where the ignition is cut is the compression stroke or the exhaust stroke, by determining the fluctuation (rotational fluctuation difference or degree of decrease) in the engine speed NE after the ignition cut.

  However, for example, an event such as improper combustion may occur before and after the ignition cut, and in that case, the rotational fluctuation difference of the engine speed NE after the ignition cut, that is, the degree of decrease may change. The engine speed NE indicated by a broken line in FIG. 4B is an example in a case where the degree of decrease in the engine speed NE after the ignition cut in the compression stroke is changed due to incorrect combustion. In the example shown in the figure, it can be seen that the degree of decrease in the engine speed NE after the ignition cut is reduced from ΔNE to ΔNEA due to incorrect combustion.

  Therefore, as shown in the patent document 1, just by comparing the degree of decrease in the engine speed NE after ignition cut with a predetermined value (ΔNE), as shown in the figure, the degree of decrease in the engine speed NE after ignition cut. Changes to ΔNEA, there arises a disadvantage that the compression stroke cannot be determined. That is, as described above, when the degree of decrease in the engine speed NE after the ignition cut is changed, there may be a case where the stroke determination cannot be performed accurately.

  Therefore, in the present invention, the ignition cut is performed only in one of the strokes, and the stroke determination is not performed based on whether or not the degree of decrease in the engine speed NE thereafter exceeds a predetermined value, but the A stroke and the B stroke, That is, the ignition cut is performed in both the compression stroke and the exhaust stroke, and the rotational fluctuation difference ΔNEA of the engine speed NEmfA after the ignition cut in the A stroke and the rotational fluctuation difference of the engine speed NEmfB after the ignition cut in the B stroke. The stroke is discriminated by comparing with ΔNEB.

  Returning to the description of FIG. 3, it is determined in S120 whether or not the rotational fluctuation difference ΔNEA is larger than ΔNEB. If the determination is affirmative, the process proceeds to S122. Advances to S124 and determines that the B stroke is the compression stroke. That is, the rotational fluctuation difference ΔNEA, which is the degree of decrease in the engine speed NEmfA, is compared with the rotational fluctuation difference ΔNEB, which is the degree of decrease in the engine speed NEmfB, and the stroke having the larger degree of reduction (rotational fluctuation difference) is compressed. Judged as a stroke. In this way, by determining the stroke by comparing the rotation fluctuation difference ΔNEA and ΔNEB, the stroke determination can be performed with high accuracy even when the degree of decrease in the engine speed NE after the ignition cut changes. it can.

  Next, in S126, it is determined whether or not the processes from S102 to S124 are repeated. The process from S102 to S124 is repeated in order to further improve the accuracy of the stroke determination. In the first S126, the determination is affirmed and the process returns to S102.

  When the processes from S102 to S124 are repeated, the ignition cut is not performed in an arbitrary stroke in S108, but the ignition cut is performed again in the stroke in which the ignition cut was performed in the previous S108, that is, the A stroke. In other words, if the ignition cut was executed in the previous compression stroke (normal ignition side), the ignition cut was executed in the compression stroke again, while the ignition cut was executed in the previous exhaust stroke (abandoned fire side). This time, the ignition cut is executed in the exhaust stroke. The same applies to the processing of S114.

  Whether or not to repeat the process in S126 after the second time is determined based on whether or not a plurality of stroke determination results obtained by repeating S102 to S124 substantially coincide. If the plurality of stroke determination results do not substantially match, the determination is negative and the process returns to S102. On the other hand, if the plurality of stroke determination results approximately match, this sub-routine flowchart is terminated.

  However, in the present invention, as described above, since the stroke determination is performed by comparing the rotation fluctuation difference ΔNEA and ΔNEB, the stroke determination can be performed with a single comparison with high accuracy. Therefore, it is not always necessary to repeat the processing from S102 to S124.

  Returning to the description of the flow chart of FIG. 2, the process then proceeds to S12 to execute ignition control. Specifically, the ignition signal is controlled so that ignition is performed only in the stroke determined as the compression stroke of the A stroke and the B stroke as a result of the stroke determination performed in S120 to S124 in the flowchart of FIG. To do. That is, the ignition signal generated in the stroke determined as the compression stroke is selected from the ignition signals generated each time the crankshaft 32 makes one rotation, and an ignition command is issued to the ignition coil based on the selected ignition signal. Send it out.

  As described above, in the first embodiment of the present invention, the ignition control of the general-purpose engine (engine) 10 that controls the ignition signal so that the ignition is performed in the two strokes of the compression stroke and the exhaust stroke of four cycles. In the apparatus, an engine speed detecting means (power coil) 44 for detecting an engine speed NE of the general-purpose engine, and an average engine speed NEave for calculating an average engine speed NEave over a predetermined time based on the detected engine speed. Number calculation means (ECU 84, S10, S104) and first ignition stop control for controlling the ignition signal so that ignition is stopped (cut) at least once in one of the two strokes (A stroke) Means (ECU84, S10, S108) and a stroke (B stroke) different from the stroke in which ignition is stopped by the first ignition stop control means. The second ignition stop control means (ECU 84, S10, S114) for controlling the ignition signal so as to stop the ignition at least once, and at least the ignition by the calculated average engine speed and the first ignition stop control means First difference calculating means (ECU 84, S10, S112) for calculating a difference (rotational fluctuation difference) ΔNEA from the engine speed NEmfA detected after stopping once, the calculated average engine speed and the second Second difference calculation means (ECU 84, S10, S118) for calculating a difference (rotational fluctuation difference) ΔNEB from the engine speed NEmfB detected after ignition is stopped at least once by the ignition stop control means; and the first difference Comparing the difference calculated by the calculating means with the difference calculated by the second difference calculating means, the first point Stroke discriminating means (ECU 84, S10, S120 to S124) for discriminating which one of the stroke in which the ignition is stopped by the stop control means and the stroke in which the ignition is stopped by the second ignition stop control means is the compression stroke; Since it is configured to include ignition signal control means (ECU84, S12) for controlling the ignition signal so that ignition is performed in the compression stroke determined by the stroke determination means, the first ignition is stopped by comparing the difference It is possible to accurately determine which of the stroke in which the ignition is stopped by the control means and the stroke in which the ignition is stopped by the second ignition stop control means, and only the normal ignition in the compression stroke can be performed. it can.

  Further, the stroke determination means determines that the stroke in which the ignition is stopped by the first ignition stop control means when the difference calculated by the first difference calculation means is larger than the difference calculated by the second difference calculation means. Since it is configured to discriminate from the compression stroke (ECU 84, S10, S120, S122), it is possible to discriminate between the compression stroke and the exhaust stroke with higher accuracy, and it is possible to reliably perform only normal ignition in the compression stroke. .

  Further, the stroke determination unit performs the comparison between the difference calculated by the first difference calculation unit and the difference calculated by the second difference calculation unit a plurality of times, and based on the comparison result performed a plurality of times. Thus, it is determined whether the stroke in which the ignition is stopped by the first ignition stop control means or the stroke in which the ignition is stopped by the second ignition stop control means is the compression stroke (ECU 84, S10, S102 to S126). Since it comprised, it becomes possible to discriminate | determine a compression stroke and an exhaust stroke much more accurately, and only the regular ignition in a compression stroke can be performed more reliably.

  FIG. 5 is an explanatory diagram for explaining the waveform of the electromotive force generated in the exciter coil 48 of the ignition control device for a general-purpose engine according to the second embodiment, and FIG. 6 is a circuit block diagram of the ignition device including the exciter coil 48. It is.

  A general-purpose engine ignition control apparatus according to a second embodiment will be described with reference to FIGS.

  Description will be made focusing on differences from the first embodiment. In the first embodiment, the stroke determination is performed so that ignition (ignition fire) is not performed in the exhaust stroke. However, by this, an electromotive voltage (ignition voltage) for discard fire that has been conventionally used in the exhaust stroke is reduced. It becomes unnecessary. Therefore, the ignition control device for a general-purpose engine according to the second embodiment uses (utilizes) the unnecessary electromotive voltage for abandoned fire as the power supply voltage of the absolute pressure sensor 80.

  The ignition device for the engine 10 requires a power source for ignition, a power source for the CPU in the ignition device (hereinafter simply referred to as “CPU”), and a power source for the absolute pressure sensor 80. The engine 10 is used for automobiles, outboard motors, and the like. Unlike the engine that does not have a battery. Therefore, in order to secure these power sources, it has been necessary to devise measures such as strengthening the magnet of the flywheel 38 and changing the specifications and configuration of the windings and the iron core. In some cases, it was necessary to add a separate power source. However, if the electromotive voltage used for abandoned fire can be used as the power supply voltage of the absolute pressure sensor 80, it is not necessary to strengthen the magnet of the flywheel 38 or to change the specifications and configuration of the winding and the iron core. There is no need to prepare a power supply separately.

  As shown in FIG. 5, in the exciter coil 48, an electromotive voltage is generated twice on the negative side and once on the positive side at the timing of ignition. Usually, the two electromotive voltages on the − side are used as a power source for the CPU, and the electromotive voltage on the + side is used as a power source for ignition. Therefore, the positive electromotive voltage for ignition generated at the exhaust stroke, that is, at the timing of abandoned fire is used as the power supply voltage of the absolute pressure sensor 80. The two electromotive voltages on the negative side are used as they are as the power source for the CPU even at the timing of the fire.

  As shown in FIG. 6, the ignition device includes a CPU 90 and an ignition coil 92 in addition to the exciter coil 48 and the absolute pressure sensor 80. The exciter coil 48 is connected to the ignition coil 92 via the capacitor C or the thyristor A, branches on the upstream side of the capacitor C, and passes through the thyristor B and the regulator (shown as “REG” in the drawing) to the absolute pressure sensor 80. Also connected. The CPU 90 is connected to the gates of the thyristor A and the thyristor B. When an ON signal is transmitted from the CPU 90 to the gate, the anode and the cathode of the thyristor A and the thyristor B are brought into conduction.

  In FIG. 6, the thyristor B is always turned off until the stroke determination is completed, so that the negative electromotive voltage of the exciter coil 48 is stored in the capacitor C, while the thyristor is in response to a signal from the CPU 90 at a predetermined ignition timing. By turning on A, ignition (regular ignition and discarded fire) is performed.

  Thereafter, when the stroke determination is completed, the ignition is continued as before at the timing of normal ignition, but the thyristor B is turned on at the timing at which the ignition was performed. Thereby, the + side electromotive voltage of the exciter coil 48 and the electric power stored in the capacitor C can be used as the power supply voltage of the absolute pressure sensor 80.

  As described above, the second embodiment of the present invention includes the load detection sensor (absolute pressure sensor) 80 for detecting the load of the general-purpose engine, and ignition is performed in the compression stroke by the ignition control means. After the ignition signal control is started, the ignition voltage (electromotive voltage) used for ignition in the exhaust stroke is used as the power supply voltage of the load detection sensor. Effective use of the ignition voltage for ignition in the exhaust stroke that has disappeared can be achieved. Further, in order to secure the power supply voltage of the load detection sensor 80, for example, it is not necessary to reinforce the magnetic force of the magnet of the flywheel 38, or to change the specifications and configuration of the winding and the iron core, or it is necessary to prepare a separate power source or the like Nor.

  Since the remaining configuration and effects are the same as those of the first embodiment, description thereof is omitted.

  As described above, in the first and second embodiments of the present invention, the general-purpose engine (engine) 10 that controls the ignition signal so that ignition is performed in the two strokes of the compression stroke and the exhaust stroke of four cycles. In the ignition control device, an engine speed detecting means (power coil) 44 for detecting an engine speed NE of the general-purpose engine, and an average for calculating an average engine speed NEave over a predetermined time based on the detected engine speed The engine speed calculation means (ECU 84, S10, S104) and a first ignition that controls the ignition signal so that ignition is stopped (cut) at least once in one of the two strokes (A stroke) A process (ECU84, S10, S108) that is different from the process in which ignition is stopped by the first ignition stop control means ( Ignition is performed by the second ignition stop control means (ECU 84, S10, S114) for controlling the ignition signal so that the ignition is stopped at least once in the stroke), the calculated average engine speed and the first ignition stop control means. First difference calculating means (ECU 84, S10, S112) for calculating a difference (rotational fluctuation difference) ΔNEA from the engine speed NEmfA detected after at least one stop, and the calculated average engine speed and the Second difference calculating means (ECU 84, S10, S118) for calculating a difference (rotational fluctuation difference) ΔNEB from the engine speed NEmfB detected after the ignition is stopped at least once by the second ignition stop control means; Comparing the difference calculated by the first difference calculating means with the difference calculated by the second difference calculating means, Stroke discriminating means (ECU 84, S10, S120 to S124) for discriminating which one of the stroke in which the ignition is stopped by the first ignition stop control means and the stroke in which the ignition is stopped by the second ignition stop control means is the compression stroke; And an ignition control means (ECU 84, S12) for controlling an ignition signal so that ignition is performed in the compression stroke determined by the stroke determination means.

  Further, the stroke determination means determines that the stroke in which the ignition is stopped by the first ignition stop control means when the difference calculated by the first difference calculation means is larger than the difference calculated by the second difference calculation means. The compression stroke is determined (ECU 84, S10, S120, S122).

  Further, the stroke determination unit performs the comparison between the difference calculated by the first difference calculation unit and the difference calculated by the second difference calculation unit a plurality of times, and based on the comparison result performed a plurality of times. Thus, it is determined whether the stroke in which the ignition is stopped by the first ignition stop control means or the stroke in which the ignition is stopped by the second ignition stop control means is the compression stroke (ECU 84, S10, S102 to S126). Configured.

  In the second embodiment, a load detection sensor (absolute pressure sensor) 80 for detecting the load of the general-purpose engine is provided, and an ignition signal is generated so that ignition is performed in the compression stroke by the ignition control means. After the start of control, the ignition voltage (electromotive voltage) used for ignition in the exhaust stroke is used as the power supply voltage of the load detection sensor.

  Although the single cylinder engine has been described in the embodiments, the present invention can be applied to a multi-cylinder engine.

  Moreover, although the specific numerical values are shown for the displacement of the engine 10, the complete explosion speed, the idle speed, etc., these are merely examples and are not limited.

  10 engine (general purpose engine), 44 power coil, 48 exciter coil, 84 ECU (electronic control unit), 80 absolute pressure sensor (load detection sensor)

Claims (4)

  In a general-purpose engine ignition control device for controlling an ignition signal so that ignition is performed in two strokes of a compression cycle and an exhaust stroke of four cycles, an engine speed detecting means for detecting an engine speed of the general-purpose engine, An average engine speed calculating means for calculating an average engine speed over a predetermined time based on the detected engine speed, and an ignition signal so as to stop ignition at least once in either of the two strokes First ignition stop control means for controlling the ignition, and second ignition stop control means for controlling the ignition signal so as to stop the ignition at least once in a stroke different from the stroke where the ignition was stopped by the first ignition stop control means. And an error detected after the ignition is stopped at least once by the calculated average engine speed and the first ignition stop control means. A first difference calculating means for calculating a difference from the gin speed, and a difference between the calculated average engine speed and the engine speed detected after the ignition is stopped at least once by the second ignition stop control means. The second difference calculating means for calculating the difference, the difference calculated by the first difference calculating means and the difference calculated by the second difference calculating means are compared, and the ignition is stopped by the first ignition stopping control means. Ignition is performed in the compression stroke determined by the stroke determination means and stroke determination means for determining which of the compression stroke and the stroke whose ignition is stopped by the second ignition stop control means. An ignition control device for a general-purpose engine, comprising ignition control means for controlling an ignition signal.   When the difference calculated by the first difference calculation unit is larger than the difference calculated by the second difference calculation unit, the stroke determination unit determines that the stroke where the ignition is stopped by the first ignition stop control unit is the compression The general-purpose engine ignition control device according to claim 1, wherein the ignition control device is determined as a stroke.   The stroke determination unit performs the comparison between the difference calculated by the first difference calculation unit and the difference calculated by the second difference calculation unit a plurality of times, and based on the comparison result performed a plurality of times. 3. The method according to claim 1, wherein it is determined which of the stroke in which the ignition is stopped by the first ignition stop control means and the stroke in which the ignition is stopped by the second ignition stop control means is the compression stroke. General-purpose engine ignition control device.   A load detection sensor for detecting the load of the general-purpose engine is provided, and is used for ignition in the exhaust stroke after the ignition control is started by the ignition control means so that ignition is performed in the compression stroke. The ignition control device for a general-purpose engine according to any one of claims 1 to 3, wherein the ignition voltage thus used is used as a power supply voltage for the load detection sensor.

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