JP3813921B2 - Internal combustion engine start method and starter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starting method and a starting device for starting an internal combustion engine such as a two-cycle gasoline engine with an electric motor, and more particularly to a small and small output motor that can be started smoothly and reliably. About.
[0002]
[Prior art]
For example, a cell motor starter for starting an internal combustion engine such as a small air-cooled two-cycle gasoline engine mounted on a portable work machine such as a chainsaw with an electric motor usually reduces the driving force of the electric motor. It is directly transmitted to the crankshaft of the internal combustion engine via a gear mechanism (see, for example, Patent Document 1).
[0003]
However, in the conventional cell motor type starter, since the driving force of the electric motor is directly transmitted to the crankshaft as it is, the cell motor naturally has a torque and a rotational speed necessary for starting the engine. Therefore, it was necessary to use a large motor with a large output.
[0004]
Therefore, the power consumption of the motor also increases, and accordingly, a battery with a large capacity is required, and at the time of starting the engine, a strong impact is applied to the motor and its power transmission system, so the strength of the components of the starter device, There is a problem that rigidity is required, the total weight is increased, durability is lowered, and a failure due to kickback or the like is likely to occur.
[0005]
On the other hand, since the above-mentioned cell motor type starter has the above-described problems, a manual type recoil starter is often adopted as a starter for an internal combustion engine of a portable work machine such as a chain saw. The recoil starter usually includes a drive unit composed of a rope reel or the like around which a recoil rope is wound, and a driven unit composed of a centrifugal ratchet mechanism or the like, and pulls the recoil rope (recoil handle) to And the rotation of the rope reel is transmitted to the crankshaft of the internal combustion engine via the driven portion to start the internal combustion engine.
As for the recoil starter as described above, the applicant of the present invention has previously proposed a buffering / accumulating means made of a spring or the like between the driving unit and the driven unit.
[0006]
In the recoil starter according to this proposal, the first half of the recoil rope pulling operation (recoiling operation) is provided by interposing, for example, a spring mechanism as a buffering / accumulating means between the driving unit and the driven unit. In the process (until the piston reaches top dead center), the buffering effect of the mainspring mechanism is obtained, and the pulling force of the recoil rope is stored in the mainspring mechanism, and in the latter half of the process, the stored pulling is performed. The force and the pulling force actually pulled in the second half process become a resultant force, which becomes the force for starting the internal combustion engine. For this reason, fluctuations in the pulling force of the rope can be suppressed as much as possible, the rope pulling operation can be performed smoothly, and even an operator with weak force can easily start the engine (for example, Patent Documents) 2).
[0007]
For example, a spring mechanism is interposed between the driving unit and the driven unit as a buffering / accumulating means. It is conceivable to add a power storage means (for example, see Patent Document 3).
[0008]
When starting the engine with the cell motor type starter provided with such a buffering / accumulating means, a start switch provided separately is pushed. Thereby, the electric motor is energized for a predetermined time (for example, about 2 to 3 seconds) from the mounted battery, and the electric motor (the output rotation shaft thereof) rotates for the predetermined time, and the rotational driving force of the electric motor Is transmitted to the crankshaft of the internal combustion engine via the speed reduction mechanism, the mainspring mechanism constituting the buffer / accumulation means, and the driven portion.
[0009]
In this case, in the first half of the driving process by the electric motor (the compression stroke until the piston of the internal combustion engine reaches the top dead center from the bottom dead center), the buffering effect by the mainspring mechanism is obtained and the driving of the electric motor is performed. In the latter half of the process (expansion stroke from the top dead center to the bottom dead center), the stored driving force and the electric motor are actually The driving force to be output becomes a resultant force, which overcomes engine compression and becomes a force for starting the internal combustion engine.
For this reason, even with a small electric motor with a small output, the internal combustion engine can be started smoothly and reliably.
[0010]
[Patent Document 1]
Japanese Utility Model Publication No. 63-177666 (first page, FIG. 2)
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-161836 (pages 1 to 6, FIGS. 1 to 3)
[Patent Document 3]
JP 2002-235640 A (pages 1 to 5, FIGS. 1 to 8)
[0011]
[Problems to be solved by the invention]
However, even when starting with a cell motor type starter provided with a buffering / accumulating means as described above, the internal combustion engine may fail to start smoothly due to the ignition system not operating.
[0012]
To explain this in detail, generally, an ignition system of an internal combustion engine includes an ignition generator configured to generate ignition power by rotation of a crankshaft, and ignition power (output) obtained from the ignition generator. An ignition coil that boosts the voltage) to a high voltage, and an ignition plug that ignites the air-fuel mixture in the cylinder by spark discharge using the high voltage from the ignition coil. The ignition power generator generally includes a magnet that is held so as to rotate integrally with the crankshaft, and a power generation coil that is disposed close to a predetermined position on the outer peripheral side of the magnet, and the crankshaft When the motor rotates, ignition power is generated in the coil winding of the power generation coil by the magnet, and this ignition power (output voltage) is led to the ignition coil and boosted to a high voltage. The spark plug sparks and the mixture in the cylinder is ignited.
[0013]
In this case, the output voltage of the ignition generator increases as the rotation speed (angular speed) of the crankshaft increases, and therefore the voltage applied to the spark plug increases as the angular speed of the crankshaft increases. .
In addition, the ignition timing in the internal combustion engine is normally set to a timing at which the piston is around 30 ° before top dead center, as shown in FIG. In the period J immediately before reaching 30 ° before the dead center, the ignition power is obtained.
[0014]
However, when starting with an ultra-small cell motor type starter provided with a buffering / accumulating means as described above, the piston is in the compression stroke during the period J, and the driving force of the electric motor Is the time when the energy is stored in the buffer / power storage means, the angular speed of the crankshaft is slower than the speed required to obtain the required ignition power, and the output voltage of the ignition generator is small. For this reason, a required high voltage (usually about 15,000 V or more) is not applied to the spark plug, the spark plug does not perform effective spark discharge, and the air-fuel mixture is not ignited. It will not start.
[0015]
The present invention has been made in view of the above-described problems, and an object of the present invention is to enable an internal combustion engine to be started smoothly and reliably even with a small electric motor having a small output. An internal combustion engine start method and starter capable of reducing power consumption, reducing battery capacity, reducing total weight, improving durability, reducing failure, and the like are provided. There is.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, a starting method according to the present invention includes an ignition generator configured to generate ignition power by rotation of a crankshaft, and an ignition power obtained from the ignition generator at a high voltage. And an ignition system having an ignition coil that boosts the pressure to the inside and an ignition plug that ignites an air-fuel mixture in the cylinder by spark discharge with a high voltage from the ignition coil, and an electric motor as a starting drive source, In the middle of the power transmission system between the electric motor and the driven portion on the crankshaft side, in the process of driving the electric motor, the electric motor is driven to store power while buffering with the driven portion. And a starter having a buffer / accumulating means for driving the driven portion interposed therebetween, wherein the start of the expansion stroke after the piston has passed the top dead center The period during which the piston is between 5 ° and 70 ° after top dead center The ignition power generator is configured to generate ignition power in the capacitor, the ignition power obtained from the ignition power generator is charged in a capacitor, and the ignition power charged in the capacitor is The ignition coil is discharged, and the spark plug is spark-discharged by a high voltage from the ignition coil.
[0017]
An internal combustion engine starter according to the present invention basically includes an ignition generator configured to generate ignition power by rotation of a crankshaft, and ignition power obtained from the ignition generator. An ignition system having an ignition coil that boosts to a high voltage, and an ignition plug that ignites an air-fuel mixture in the cylinder by spark discharge with the high voltage from the ignition coil, and an electric motor as a starting drive source In the middle of the power transmission system between the electric motor and the driven portion on the crankshaft side, in the process of driving the electric motor, the electric motor is driven to buffer and accumulate the force while buffering the driven portion. And a starter formed by interposing a buffering / accumulating means for driving the driven portion by accumulating force.
[0018]
And the ignition generator is in the first stage of the expansion stroke after the piston passes through the top dead center. The period during which the piston is between 5 ° and 70 ° after top dead center And a capacitor for charging the ignition power obtained from the ignition generator is attached to the ignition coil at a predetermined timing. The spark plug is spark discharged by a high voltage from the ignition coil.
[0019]
The driven portion preferably includes a centrifugal clutch that is disengaged by a centrifugal force generated by rotation of the driven side, and is interlocked with the drive side via the centrifugal clutch.
[0020]
In a preferred embodiment, a one-way clutch and the buffer / accumulation means are interposed in series between the electric motor and the centrifugal clutch for power transmission.
In another preferred embodiment, a speed reduction mechanism is interposed between the buffer / accumulation means and the electric motor. In this case, the speed reduction mechanism preferably has a reduction ratio set to 1/60 to 1/100. Is done.
[0021]
The buffer / accumulation means is preferably a storage box disposed on the electric motor side, an activation pulley disposed on the driven unit side, and between the storage box and the activation pulley. The spring member is interposed, and one end and the other end of the spring member are locked to the storage box and the start pulley, respectively.
[0022]
In a further preferred aspect, a recoil drive unit is attached to the drive side separately from the electric motor, and the recoil drive unit is rotated by winding the recoil rope and pulling the recoil rope. A rope reel; a recoil urging means for reversing the rope reel to wind the recoil rope; and a recoil ratchet mechanism for transmitting the rotation of the rope reel to the buffering / accumulating means.
[0023]
In this case, the buffering / accumulating means preferably has a one-way clutch that rotates the storage box only in one direction.
On the other hand, a chain saw according to the present invention includes the starter, and the internal combustion engine is mounted horizontally in a main body housing with its head facing rearward, and one side of the main body housing. A cooling fan driven by the internal combustion engine and the starter are disposed in a part, and an air intake slit is formed on the left side so as to cover the cooling fan and the starter. A starter case is attached.
[0024]
In a preferred embodiment of the starting method and the starting device according to the present invention configured as described above, a start switch provided separately is pushed when starting the engine. As a result, the electric motor is energized from the on-board battery to the electric motor for a predetermined time (for example, about 2 to 3 seconds), and the electric motor (the output rotation shaft thereof) rotates for the predetermined time, and the rotational driving force of the electric motor Is transmitted to the crankshaft of the internal combustion engine via the speed reduction mechanism, the one-way clutch, the buffer / accumulation means, and the driven portion.
[0025]
In this case, in the first half of the driving process by the electric motor (the compression stroke until the piston of the internal combustion engine reaches top dead center), the buffering effect by the buffering / accumulating means is obtained and the driving of the electric motor is performed. The force is stored in the buffering / accumulating means, and in the latter half of the process, the stored driving force and the driving power actually output by the electric motor in the latter half of the process become a combined force, and the engine compression This is a force that starts the internal combustion engine.
[0026]
Here, in the starting device of the present invention, the ignition power generator is provided in the first stage of the expansion stroke after the piston has passed through the top dead center, preferably, as shown in FIG. The ignition power (output voltage) is obtained during a period K between 5 ° and 70 °. The period K is immediately after the piston has transitioned from the compression stroke to the expansion stroke, and is a period during which the driving force stored in the buffering / accumulating means composed of the spring member or the like is released in the compression stroke. The angular speed of the crankshaft is increased. For this reason, the output voltage of the ignition generator is also increased. For this reason, the capacitor is charged with a sufficiently high voltage, and accordingly, the required high voltage (usually 15, 15) is supplied from the ignition coil to the spark plug. 000 V or more) is applied, the spark plug effectively sparks discharge, the air-fuel mixture is reliably ignited, and the internal combustion engine starts smoothly.
[0027]
As described above, in the present invention, since the ignition power is obtained in the ignition power generator in the first stage of the expansion stroke in which the angular velocity of the crankshaft increases, the rotation speed of the crankshaft at the time of start-up Even if it is low (for example, about 200 to 300 rpm), the internal combustion engine can be reliably started. For this reason, even with a small electric motor with a small output, the internal combustion engine can be started smoothly and reliably. As a result, the power consumption of the electric motor is reduced, the battery capacity is reduced, the total weight is reduced, and the durability is increased. The reliability and the reliability can be improved, and the portable power working machine such as the chain saw can be reduced in size and weight. .
[0028]
In addition, since the ignition power from the ignition generator is charged in the capacitor, when the internal combustion engine is restarted after the operation of the internal combustion engine is completed, the first rotation From the above, the high voltage power remaining in the capacitor can be additionally used, so that starting is more reliable.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows a chain saw 200 in which an embodiment of a starter for a two-cycle internal combustion engine according to the present invention is adopted. FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
[0030]
The illustrated chainsaw 200 includes a small air-cooled two-cycle gasoline engine (hereinafter referred to as an internal combustion engine) 210 having a displacement of about 23 to 50 mL as a working unit driving power source in a main body housing 220 made of synthetic resin. The cylinder 211 is mounted horizontally, the crankshaft 212 is directed in the left-right direction, and the head 213 of the cylinder 211 is mounted rearward. A number of cooling fins 216 are formed in the cylinder 211, and a spark plug 180 is attached to the head 213 so as to be inclined obliquely rearward.
[0031]
Although not shown, a clutch cover is attached to the right side (the back side in FIG. 1) of the main body housing 220, and a guide bar 231 is slidable as a working part on the front side thereof. A saw chain set 230 comprising a saw chain 232 that is wound around is attached, and the saw chain 232 is rotated by the internal combustion engine 210.
[0032]
Further, a cooling fan 35 and a starter 5 described later are disposed on the left side 220L (the front side in the figure) of the main body housing 220, and the left side 220L covers the cooling fan 35 and the starter 5 so as to cover them. Is provided with a starter case 221 as an exterior cover, on which a large number of air intake slits 222 are formed.
[0033]
On the other hand, a U-shaped top handle 240 with a throttle lock lever 245 and a throttle trigger 246 incorporated therein is disposed on the upper surface of the main body housing 220, and a hand guard 248 is disposed on the front side thereof. The auxiliary handle 247 is disposed to be inclined rearward and downward.
The starter 3 of this embodiment employed in the chain saw 200 includes an ignition system 100 (see FIG. 4) and a starter 5 that serves both as a cell motor type and a recoil type.
[0034]
As shown in FIG. 4, the ignition system 100 is obtained from an ignition generator 110 configured to generate ignition power by the rotation of the crankshaft 212 of the internal combustion engine 210, and the ignition generator 110. The capacitor 140 is charged with power through the diode 120, the ignition coil 150 boosts the discharge from the capacitor 140, the discharge control thyristor 130 for discharging the capacitor 140, and boosted by the ignition coil 150. The timing at which the ignition plug 180 to which a high voltage is applied and the discharge thyristor 130 are operated ON (conductive) / OFF (non-conductive), that is, the ignition timing for setting the ignition timing of the air-fuel mixture by the ignition plug 180 A setting circuit 170.
[0035]
As shown in FIG. 2, the ignition power generator 110 is embedded and fixed in a cooling fan 35 that is held so as to rotate integrally with one end (left end) 212a of the crankshaft 212, and a part of the ignition power generator 110 is exposed to the outside. The exposed pole 111 and the magnet 113, and the power generation coil 112 wound around the core 112a disposed close to a predetermined position on the outer peripheral side of the magnet 113, etc., and when the crankshaft 212 rotates, A magnet 113 generates ignition power in the coil winding of the power generation coil 112.
[0036]
In the starting device 3 of the present embodiment, the ignition power generator 110 includes the first stage of the expansion stroke after the piston 214 in the cylinder 211 passes through the top dead center, preferably as shown in FIG. The ignition power (output voltage) is obtained during a period K in which the piston is at 5 ° to 70 ° after top dead center. The ignition timing controlled by the ignition timing setting circuit is a timing at which the piston 214 is around 30 ° before the top dead center TDC.
[0037]
On the other hand, the starter 5 is disposed close to and opposed to the one end (left end) 212a of the crankshaft 212, and the main starting method is a cell motor type, but when the battery is insufficiently charged, etc. However, in order to cope with the case where the starter cannot be started with the cell motor type, or when the motor or the like fails, the recoil type (manual type) can be started.
[0038]
The starter 5 has the starter case 221 attached to the left side portion 220L of the main body housing 220, and is a drive unit for starting the internal combustion engine 210 near the bottom in the starter case 221. An electric motor 70 having an output of about 50 W and about 1500 rpm, which is supplied with electric power by a rechargeable battery 90 of about 2.4 V, 2.1 Ah, which is a DC power source as a drive source, is stored and held in a horizontal position.
[0039]
In addition, a recoil drive 6 that is rotated by pulling a recoil rope 21 (recoil handle 22) is disposed in the starter case 221, and can be rotated independently from the recoil drive 6; and A driven unit 7 to which power from the electric motor 70 and the recoil-type drive unit 6 is transmitted is disposed.
[0040]
The starter case 221 has a fixed support shaft 12 projecting inward, and a rope reel 20 around which the recoil rope 21 is wound is rotatably fitted on the base end side of the fixed support shaft 12. In addition, a shock absorbing / accumulating mechanism 15 is externally fitted between the protruding end side of the fixed support shaft 12, that is, between the rope reel 20 and the cooling fan 35 constituting the driven portion 7, and for retaining the Screws 14 are screwed together. The buffer / accumulation mechanism 15 is disposed on the electric motor 70 side so as to be able to rotate independently from the rope reel 20, and the storage box 16 having a cylindrical storage portion 16a, the driven portion 7 side. And the starting pulley 17 having a cylindrical storage portion 17a, and the storage box 16 and the starting pulley 17 so as to straddle between the cylindrical storage portions 16a and 17a. The coil spring member 18 for buffering / accumulating power is provided. The storage box 16 and the start pulley 17 are coaxially rotatable relative to each other, and one end 18a and the other end 18b of the coil spring member 18 are respectively connected to the storage box 16 and the start pulley. 17, and by rotating one of the storage box 16 and the start pulley 17 relative to the other, a rotational force is applied to the other.
[0041]
Here, on the rotation axis O of the crankshaft 212, the central axis of the fixed support shaft 12, the rotation axes of the rope reel 20 and the buffering / accumulating mechanism 15, and the cooling that constitutes the driven portion 7. A rotation axis of the fan 35 is disposed, and an output rotation shaft 72 of the electric motor 70 is disposed so as to be orthogonal to the rotation axis O.
[0042]
The driving force of the electric motor 70 is transmitted to the buffer / accumulation mechanism 15 via a speed reduction mechanism 80, and further from the buffer / accumulation mechanism 15 via the cooling fan 35, the internal combustion engine 210. It is transmitted to the crankshaft 212.
[0043]
The speed reduction mechanism 80 includes a small-diameter gear 81 that is externally fitted and fixed to the output rotation shaft 72 of the electric motor 70, as can be understood by referring to FIG. 3 in addition to FIG. 2. The rotational driving force of the large and small two-stage gears 82 and 83 that are rotatably fitted on the support shaft 75 arranged in parallel to the small-diameter gear 81 → the output rotary shaft 72 → parallel to the output rotary shaft 72. A large-diameter gear 84 and a small bevel gear 85 that are externally fitted and fixed to the rotary shaft 76 that is arranged, and a large bevel gear that is fitted and fixed to the rotary shaft 77 that is arranged parallel to the rotary axis O of the crankshaft 212 86, and the rotation of the large bevel gear 86 is provided in a bowl shape on the outer periphery of the storage box 16 meshed with a small-diameter gear 87 externally fitted to the rotary shaft 77 via a one-way clutch 95. Is transmitted to the large-diameter gear 88 The storage box 16 is adapted to be rotated in one direction. In this case, the reduction ratio of the reduction mechanism 80 is about 1/80.
[0044]
The one-way clutch 95 is interposed to rotate the storage box 16 from the recoil-type drive unit 6 side without receiving a braking action by the speed reduction mechanism 80. The buffer / accumulation mechanism 15 is interposed in series between the electric motor 70 and the driven portion 7 (centrifugal clutch ratchet mechanism 30 described later) for power transmission.
[0045]
As a separate system, the rotation of the rope reel 20 is also transmitted to the crankshaft 212 of the internal combustion engine 210 via the buffer / accumulation mechanism 15 and the cooling fan 35. Yes.
On the other hand, the rope reel 20 is disposed between the starter case 221 and the storage box 16, and the rope reel 20 has a stepped disk shape, and the recoil rope 21 is wound around the outer periphery thereof. A groove portion 20a to be mounted is formed, and a cylindrical boss portion 26 that is rotatably fitted to the storage box 16 is provided at the center of the inner periphery thereof. Further, a recoil ratchet mechanism 40 having the same configuration as that of a recoil starter having a conventionally known configuration is disposed between the rope reel 20 and the storage box 16, and the recoil ratchet mechanism 40 and the storage box are arranged. A one-way clutch 19 that allows the storage box 16 to rotate only in the engine starting direction is interposed between the large-diameter gear 88 that is provided integrally with the gear 16.
[0046]
The recoil rope 21 is not shown in detail in the same manner as in a recoil starter having a conventionally well-known configuration, but one end is locked to the bottom of the groove 20a and the other end pulled out from the starter case 221 to the other end. A rope pulling handle 22 (see FIG. 1) is attached.
[0047]
Further, between the rope reel 20 and the starter case 221, a recoil spring 23 having an outer end locked to the rope reel 20 and an inner end locked to the starter case 221 is disposed. After the recoil rope 21 is pulled and the rope reel 20 is rotated, the rope reel 20 is returned to the original position by the restoring force accumulated in the recoil spring 23, and the recoil rope 21 is It is designed to automatically wind up.
[0048]
The follower 7 includes the cooling fan 35 and a centrifugal clutch ratchet mechanism 30. The centrifugal clutch ratchet mechanism 30 is formed on the outer periphery of the start pulley 17 and is supported by, for example, a pair of transmission engaging portions 31 and 31 and the cooling fan 35 so as to be swingable. The starting claw 36 is normally biased toward the inside (the rotation axis O side) by a biasing spring (screw recoil spring) 37 (when the engine is stopped). When the internal combustion engine 210 is started, the centrifugal force generated by the rotation of the cooling fan 35 driven from the crankshaft 212 side causes a radial direction when the internal combustion engine 210 is started. By swinging outward, the engagement with the recoil-type drive unit 6 is automatically released when the crankshaft 212 exceeds a predetermined rotational speed.
[0049]
In the starting device 3 of the present embodiment configured as described above, when starting the internal combustion engine 210, the start switch 150 disposed on the rear side of the left side surface 220L of the main body housing 220 is pushed. As a result, the electric motor 70 is energized from the battery 90 to the electric motor 70 for a predetermined time (for example, about 2 to 3 seconds), and the output rotating shaft 72 of the electric motor 70 rotates for the predetermined time. Is transmitted to the buffer / accumulation mechanism 15 via the speed reduction mechanism 80, and the crankshaft of the internal combustion engine 210 is transmitted from the buffer / accumulation mechanism 15 via the follower 7. 212.
[0050]
In this case, in the first half of the driving process by the electric motor 70 (the compression stroke until the piston 214 reaches the top dead center TDC), a buffering effect by the buffer / power accumulation mechanism 15 is obtained, and the electric motor The driving force of 70 is stored in the buffer / accumulation mechanism, and in the latter half of the process, the stored driving force and the driving force actually output by the electric motor 70 in the latter half of the process become a resultant force. Thus, the engine compression is overcome and the internal combustion engine 210 is started.
[0051]
Here, in the starting device 3 according to the present embodiment, the ignition power generator 110 is arranged such that the piston 214 passes through the top dead center TDC in the first stage of the expansion stroke, preferably as shown in FIG. The position of the magnet 113 on the cooling fan 35 and the like are appropriately determined so that ignition power (output voltage) is obtained during a period K where 214 is 5 ° to 70 ° after the top dead center TDC. Has been. The period K is immediately after the piston 214 shifts from the compression stroke to the expansion stroke, and the driving force accumulated in the buffer / power accumulation mechanism 15 including the coil spring member 18 and the like is released in the compression stroke. Since it is the period, the angular velocity of the crankshaft 212 is increased. Therefore, as shown in FIG. 5 (ignoring the magnitude of the voltage value for the sake of convenience), the output voltage of the ignition generator 110 is indicated by a solid line, and the piston 214 is 5 ° after the top dead center TDC. The output voltage of the ignition power generator 110 increases during the period K that is ˜70 ° (particularly, the period K when the crank angle of the second rotation is 365 ° to 430 °). As indicated by a two-dot chain line, the capacitor 140 is charged with a high voltage, and accordingly, the required high voltage (usually about 15,000 V) from the ignition coil 150 to the spark plug 180 is obtained. The above is reliably applied, the spark plug 180 is effectively spark-discharged, the air-fuel mixture is reliably ignited, and the internal combustion engine 210 is started smoothly.
[0052]
As described above, in the present embodiment, the ignition power is obtained in the ignition power generator 110 in the first stage of the expansion stroke in which the angular velocity of the crankshaft 212 is increased. Even if the rotational speed of 212 is low (for example, about 200 to 300 rpm), the internal combustion engine 210 can be started. For this reason, even with a small electric motor with a small output, the internal combustion engine can be started smoothly and reliably. As a result, the power consumption of the electric motor is reduced, the battery capacity is reduced, the total weight is reduced, and the durability is increased. As a result, the reliability can be increased and the chain saw 200 can be reduced in size and weight.
[0053]
In addition, since the ignition power from the ignition generator 110 is charged in the capacitor 140, when the internal combustion engine 210 is restarted after the operation of the internal combustion engine 210 is completed, The high voltage remaining in the capacitor 140 from the first rotation is used, so that starting becomes more reliable.
[0054]
On the other hand, in the starting device 3 of the present embodiment, when the internal combustion engine 210 cannot be started with the above-described cell motor type (when the battery runs out or the electric motor 70 is broken, etc.), the recoil type driving unit 6 is used. Start operation. That is, when the recoil rope 21 (recoil handle 22) is pulled, the rope reel 20 is rotated in the driving direction, and the rotation of the rope reel 20 is applied to the storage box 16 via the recoil ratchet mechanism 40. Communicated.
[0055]
When the rope pulling operation is performed in this manner, the rotation of the recoil drive unit 6 is transmitted to the crankshaft 212 of the internal combustion engine 210 via the buffer / accumulation mechanism 15 and the cooling fan 35. . In this case as well, in the first half of the pulling operation (recoiling operation) of the recoil rope 21, a buffering effect by the buffering / accumulating mechanism 15 is obtained, as in the case of starting with the above-described cell motor type. The pulling force of the recoil rope 21 is stored in the buffer / accumulation mechanism 15, and in the latter half of the process, the stored pulling force and the pulling force actually pulled in the latter half of the process become a resultant force, resulting in engine compression. This is a force for starting the internal combustion engine 210.
[0056]
For this reason, the pulling force fluctuation of the rope can be suppressed as much as possible, the rope pulling operation can be performed smoothly, and even an operator with weak force can easily start the engine. In the ignition system 100, as in the case of starting with the cell motor type, the ignition power from the ignition power generator 110 is increased, and the capacitor 140 is charged with a sufficiently high voltage. A required high voltage (usually about 15,000 V or more) is applied from the coil 150 to the spark plug 180, the spark plug 180 effectively sparks discharge, and the air-fuel mixture is reliably ignited. Will start smoothly. For this reason, even if the rotation speed of the crankshaft 212 at the time of starting is low (for example, about 200 to 300 rpm), the internal combustion engine 210 can be started reliably.
[0057]
Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various designs can be made without departing from the spirit of the present invention described in the claims. Can be changed.
[0058]
【The invention's effect】
As can be understood from the above description, the internal combustion engine start method and starter according to the present invention can obtain ignition power in the ignition generator in the first stage of the expansion stroke in which the angular velocity of the crankshaft is the fastest. Therefore, even if the rotation speed of the crankshaft at the time of starting is low (for example, about 200 to 300 rpm), the internal combustion engine can be started. For this reason, even with a small electric motor with a small output, the internal combustion engine can be started smoothly and reliably. As a result, the power consumption of the electric motor is reduced, the battery capacity is reduced, the total weight is reduced, and the durability is increased. Improvement, reduction of failure, etc., increase in reliability, and reduction in size and weight of portable power working machines such as chainsaws. .
[0059]
In addition, since the ignition power from the ignition generator is charged in the capacitor, when the internal combustion engine is restarted after the operation of the internal combustion engine is completed, the first rotation The high voltage remaining in the capacitor is used, which makes starting more reliable.
[Brief description of the drawings]
FIG. 1 is a partially cutaway left side view showing a chain saw in which an embodiment of a starter for a two-cycle internal combustion engine according to the present invention is employed.
2 is an enlarged cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a partially cutaway view showing the periphery of the electric motor and the speed reduction mechanism in FIG.
FIG. 4 is a circuit diagram showing an ignition system in an embodiment of a starter according to the present invention.
5 is a graph showing an output voltage of an ignition power generator and a capacitor charging voltage provided in the ignition system shown in FIG. 4;
FIG. 6 is a diagram for explaining the power generation operation of the ignition power generator according to the present invention.
FIG. 7 is a diagram for explaining the power generation operation of a conventional ignition generator.
[Explanation of symbols]
3 Starter
5 Starter
6 Recoil drive unit
7 Follower
15 Buffer / Accumulator Mechanism (Buffer / Accumulator)
16 Storage box
17 Start pulley
18 Coil spring member
18a end
18b The other end
19 One-way clutch
20 Rope reel
21 Recoil rope
23 Recoil spring (Recoil biasing means)
30 Centrifugal clutch type ratchet mechanism (centrifugal clutch)
35 Cooling fan
40 Ratchet mechanism for recoil
70 Electric motor (drive unit)
80 Reduction mechanism
95 one-way clutch
100 ignition system
110 Generator for ignition
140 capacitors
150 Ignition coil
180 spark plug
200 chainsaw
210 2-cycle internal combustion engine
211 cylinders
212 crankshaft
213 head
214 piston
220 Body housing
220L Left side (one side)
221 Starter case
222 Slit for air intake
TDC top dead center
K Maximum electromotive force generation period

Claims (10)

An ignition power generator (110) adapted to generate ignition power by rotation of the crankshaft (212), and an ignition coil (150) for boosting the ignition power obtained from the ignition power generator (110) to a high voltage And an ignition system (100) having a spark plug (180) that sparks the high voltage from the ignition coil (150) to ignite the air-fuel mixture in the cylinder (211),
An electric motor (70) as a starting drive source is provided, and the electric motor (70) is placed in the middle of the power transmission system between the electric motor (70) and the driven portion (7) on the crankshaft (212) side. 70) In the process of driving 70), the electric motor (70) is driven to buffer and store power while buffering the driven portion (7), and the driven portion (7) is driven by the stored power. 15) a starter (5) intervening, and a starting method of the internal combustion engine (210),
Electric power for ignition is generated in a period (K) in which the piston (214) is at 5 ° to 70 ° after the top dead center in the first stage of the expansion stroke after the piston (214) passes the top dead center (TDC). The ignition power generator (110) is configured, and the capacitor (140) is charged with ignition power obtained from the ignition power generator (110), and the ignition power charged in the capacitor (140) is predetermined. The ignition coil (150) is discharged at the following timing, and the spark plug (180) is spark-discharged by a high voltage from the ignition coil (150). An ignition power generator (110) adapted to generate ignition power by rotation of the crankshaft (212), and an ignition coil (150) for boosting the ignition power obtained from the ignition power generator (110) to a high voltage ), And an ignition system (100) having a spark discharge (180) for igniting an air-fuel mixture in the cylinder (211) by spark discharge with a high voltage from the ignition coil (150), and a starting drive source The electric motor (70) is driven, and the electric motor (70) is driven in the middle of the power transmission system between the electric motor (70) and the driven portion (7) on the crankshaft (212) side. In the process, the electric motor (70) is driven to buffer the driven portion (7) while accumulating, and the buffer / accumulating means (15) for driving the driven portion (7) by the accumulated force is interposed. Was And the starter (5), equipped with a,
The ignition power generator (110) has a period (5 to 70 ° after the top dead center of the piston (214) in the first stage of the expansion stroke after the piston (214) passes the top dead center (TDC) ( K) is configured to generate ignition power, and a capacitor (140) for charging the ignition power obtained from the ignition power generator (110) is attached to the capacitor (140). An internal combustion engine starter configured to discharge electric power for ignition to the ignition coil (150) at a predetermined timing and to spark discharge the spark plug (180) by a high voltage from the ignition coil (150). . The driven portion (7) includes a centrifugal clutch (30) that is disengaged by a centrifugal force generated by rotation on the driven side, and is interlocked with the drive side via the centrifugal clutch (30). An internal combustion engine starter according to claim 2 . Between the electric motor (70) and the centrifugal clutch (30), a one-way clutch (95) and the buffer / power storage means (15) are interposed in series for power transmission. The internal combustion engine starter according to claim 3 . The internal combustion engine according to any one of claims 2 to 4 , wherein a speed reduction mechanism (80) is interposed between the buffering / accumulating means (15) and the electric motor (70). Engine starter. The starter for an internal combustion engine according to claim 5 , wherein the reduction mechanism (80) has a reduction ratio set to 1/60 to 1/100. The buffering / accumulating means (15) includes a storage box (16) disposed on the electric motor (70) side, an activation pulley (17) disposed on the driven portion (7) side, and the A spring member (18) interposed between the storage box (16) and the start pulley (17), and one end (18a) and the other end (18b) of the spring member (18), The starter for an internal combustion engine according to any one of claims 2 to 6 , characterized in that it is respectively engaged with the storage box (16) and the start pulley (17). In addition to the electric motor (70), a recoil drive unit (6) is attached to the drive side, and the recoil drive unit (6) is wound with a recoil rope (21). A rope reel (20) rotated by pulling (21), a recoil biasing means (23) for reversing the rope reel (20) to wind the recoil rope (21), and the rope reel ( recoiling ratchet mechanism for rotation to transmit the buffered-accumulating means (15) of 20) (40) and, from claim 2, characterized in that it comprises a seventh of any one A starting device for an internal combustion engine . The damping and force accumulating means (15) for an internal combustion engine according to claim 7 or 8, characterized in that it comprises the one-way clutch to rotate the storage box (16) only in one direction (19) Starter. A chain saw (200) comprising the starter for an internal combustion engine according to claim 2, wherein the internal combustion engine (210) is placed horizontally in a cylinder (211) in a main body housing (220). A cooling fan (35) driven by the internal combustion engine (210) and the starter (5) are disposed on one side (220L) of the main body housing (220) while being mounted rearward. A starter case (221) as an exterior cover having an air intake slit (222) formed on the left side (220L) so as to cover the cooling fan (35) and the starter (5). A chainsaw characterized by

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