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WO2014002957A1 - Dispositif d'alimentation en combustible destiné à un moteur, et machine-outil portative - Google Patents

Dispositif d'alimentation en combustible destiné à un moteur, et machine-outil portative Download PDF

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Publication number
WO2014002957A1
WO2014002957A1 PCT/JP2013/067264 JP2013067264W WO2014002957A1 WO 2014002957 A1 WO2014002957 A1 WO 2014002957A1 JP 2013067264 W JP2013067264 W JP 2013067264W WO 2014002957 A1 WO2014002957 A1 WO 2014002957A1
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WO
WIPO (PCT)
Prior art keywords
engine
fuel
crankshaft
fuel supply
supply device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2013/067264
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English (en)
Japanese (ja)
Inventor
秀夫 川嶌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Makita Corp
Original Assignee
Makita Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Makita Corp filed Critical Makita Corp
Publication of WO2014002957A1 publication Critical patent/WO2014002957A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M17/00—Carburettors having pertinent characteristics not provided for in, or of interest apart from, the apparatus of preceding main groups F02M1/00 - F02M15/00
    • F02M17/02—Floatless carburettors
    • F02M17/04—Floatless carburettors having fuel inlet valve controlled by diaphragm
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B63/00—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
    • F02B63/02—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for hand-held tools
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
    • F02D35/0015—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for using exhaust gas sensors
    • F02D35/0046—Controlling fuel supply
    • F02D35/0053—Controlling fuel supply by means of a carburettor
    • F02D35/0069—Controlling the fuel flow only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/16—Other means for enriching fuel-air mixture during starting; Priming cups; using different fuels for starting and normal operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/04—Feeding by means of driven pumps
    • F02M37/046—Arrangements for driving diaphragm-type pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N11/00—Starting of engines by means of electric motors
    • F02N11/003—Starting of engines by means of electric motors said electric motor being also used as a drive for auxiliaries, e.g. for driving transmission pumps or fuel pumps during engine stop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N19/00—Starting aids for combustion engines, not otherwise provided for
    • F02N19/001—Arrangements thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2400/00—Control systems adapted for specific engine types; Special features of engine control systems not otherwise provided for; Power supply, connectors or cabling for engine control systems
    • F02D2400/06—Small engines with electronic control, e.g. for hand held tools
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N19/00—Starting aids for combustion engines, not otherwise provided for
    • F02N2019/002—Aiding engine start by acting on fuel

Definitions

  • the present invention relates to an engine fuel supply device, and more particularly to an engine equipped with a diaphragm pump type carburetor, a technique for supplying fuel used for starting the engine, and a portable work machine using the engine equipped with the fuel supply device as a drive source.
  • a diaphragm pump type carburetor a technique for supplying fuel used for starting the engine
  • a portable work machine using the engine equipped with the fuel supply device as a drive source.
  • Patent Document 1 discloses the following fuel supply device.
  • the fuel storage part of the carburetor and the inside of the crankcase are always communicated via the starting fuel supply flow path regardless of the vertical position of the piston.
  • a pulsation transmission passage is formed to cause pressure fluctuations in the crankcase to act on the diaphragm pump of the carburetor, and a start-up fuel supply passage that branches from the pulsation transmission passage and leads to the fuel storage section is formed.
  • a groove is formed in the inner peripheral wall of the cylinder for communicating the opening on the crankcase side of the pulsation transmission passage with the inside of the crankcase.
  • the opening of the pulsation transmission passage also serves as an opening on the crankcase side of the starting fuel supply passage.
  • JP 2007-239545 A (paragraph number 0027)
  • a starting fuel supply flow path that branches from the pulsation transmission passage is formed, and a groove that communicates the opening of the pulsation transmission passage and the inside of the crankcase with the inner peripheral wall of the cylinder.
  • the piston is at or near the bottom dead center, and the opening of the pulsation transmission passage (also serving as the opening of the starting fuel supply passage) is blocked by the peripheral side surface of the piston. Even if it is, the fuel storage part of the carburetor and the inside of the crankcase communicate with each other via the groove and the starting fuel supply flow path, so that cranking starts without waiting for the piston to rise and the intake port to be opened.
  • the present invention drives an engine fuel supply device capable of accurately supplying the fuel used for starting the engine with a diaphragm pump type carburetor without variation, and the engine equipped with the fuel supply device.
  • An object is to provide a portable work machine as a source.
  • a fuel tank a carburetor including a diaphragm pump that is driven by pressure fluctuation generated in an engine crankcase, an electric motor connected to an engine crankshaft, A starting fuel supply that rotates the crankshaft alternately in the forward and reverse directions by a motor to cause pressure fluctuations in the crankcase, and supplies the fuel stored in the fuel tank to the engine via the carburetor A fuel supply device for the engine.
  • a portable work machine including an engine including the fuel supply device and using the engine as a drive source is configured.
  • the crankshaft is alternately rotated in the normal rotation direction and the reverse rotation direction by the electric motor, thereby causing pressure fluctuation in the crankcase.
  • the diaphragm pump provided in the carburetor is operated by this pressure fluctuation, and fuel can be supplied from the fuel tank to the carburetor. Therefore, a sufficient amount of fuel can be secured in the carburetor, and the fuel can be accurately supplied to the engine.
  • the portable work machine includes an engine including the fuel supply device, and the engine can be provided as a drive source.
  • SYMBOLS 10 Internal combustion engine (engine), 12 ... Crankshaft, 14 ... Cylinder, 16 ... Crankcase, 22 ... Piston, 40 ... Electric motor, 42 ... Rotary shaft, 44 ... Electromagnetic coil, 46 ... Permanent magnet, 48 ... Rotor 60 ... carburetor, 68 ... diaphragm, 90 ... priming pump, 98 ... fuel tank, 150 ... control unit, 152 ... ignition circuit, 154 ... motor control circuit, P1 ... intake port, P22 ... scavenging port, P3 ... exhaust port, v1, v2 ... check valves.
  • FIG. 1 shows a configuration of an internal combustion engine (engine) 10 according to an embodiment of the present invention by a longitudinal section parallel to a central axis Ctr of a crankshaft 12.
  • An engine (hereinafter simply referred to as “engine”) 10 according to the present embodiment is provided in a horticultural portable work machine, such as a brush cutter, and constitutes a drive source thereof.
  • the output of the engine 10 is transmitted to the rotary blade via the drive shaft of the brush cutter and rotates it.
  • it is not limited to brush cutters, but can be provided as a drive source for any portable work machine such as mowers, chainsaws, circular cutters (cut-off saws), sprayers, spreaders, blowers (blowers), and dust collectors. is there.
  • the engine 10 includes an electric motor 40, and the crankshaft 12 of the engine 10 and the rotating shaft 42 of the electric motor 40 are directly connected, and the output torque of the electric motor 40 is transmitted via the crankshaft 12 to a drive shaft (see FIG. (Not shown), and the output torque of the engine 10 can be transmitted to the rotating shaft 42 of the electric motor 40.
  • the electric motor 40 is not only connected to the crankshaft 12 coaxially with the rotary shaft 42 but also connected via a power transmission medium such as a gear or a chain mechanism, and can be interrupted via a clutch. You may connect to.
  • the engine 10 is a two-stroke engine. In this embodiment, a single-cylinder small two-stroke engine is adopted.
  • the engine 10 is roughly divided into a cylinder 14 and a crankcase 16, and the crankshaft 12 is pivotally supported by a bearing 18 with respect to the crankcase 16.
  • An oil seal 20 is installed inside the bearing 18.
  • the piston 22 is inserted into the cylinder 14 so as to be movable up and down, and is connected to the crankshaft 12 via a connecting rod 24.
  • the piston 22 is connected to one end portion of a connecting rod 24 by a piston pin 26, and the connecting rod 24 is connected to a crank pin 28 at the other end portion and cranked via a crank arm 30 that holds the crank pin 28.
  • the crank arm 30 includes a counterweight 32 on the side opposite to the holding portion of the crankpin 28.
  • a combustion chamber C is formed above the piston 22, and an ignition plug 34 is installed so as to face the combustion chamber C.
  • the spark plug 34 operates in response to a command signal from the control unit 150 and ignites the compressed mixture formed in the combustion chamber C.
  • the cylinder 14 has a plurality of heat radiating fins 36 protruding from the outer surface thereof.
  • the electric motor 40 is a three-phase induction type electric motor (brushless motor), and can function not only as a motor (motor) but also as a generator (generator).
  • the electromagnetic coil 44 is placed on the stationary side, the permanent magnet 46 is placed on the movable side, and the rotor (rotor) 48 that holds the permanent magnet 46 is placed outside the electromagnetic coil 44.
  • the electromagnetic coil 44 is fixed to the crankcase 16.
  • the permanent magnet 46 is fixed to an inner peripheral portion of a rotor 48 formed in a bottomed cylindrical shape, and the rotor 48 is extended to an extended portion of the crankshaft 12 extending outside the crankcase 16.
  • the crankshaft 12 is rotatably mounted on the same axis. In other words, in this embodiment, the extending portion of the crankshaft 12 also functions as the rotating shaft 42 of the electric motor 40.
  • a cooling fan 50 is formed on the outer peripheral surface of the rotor 48.
  • the control unit 150 includes an ignition circuit 152 and a motor control circuit 154, and also includes an ignition timing detection circuit, a throttle opening detection circuit, and a rotor position detection circuit (not shown) as a configuration for detecting the operating state of the engine 10. .
  • the ignition circuit 152 calculates an ignition timing Tig corresponding to the operating condition of the engine 10 and outputs a command signal corresponding to the ignition timing Tig to the ignition plug 34.
  • the motor control circuit 154 calculates an operating condition of the electric motor 40 and outputs a command signal corresponding to the operating condition to the electric motor 40. Specifically, during normal operation of the engine 10, when the output torque of the engine 10 is insufficient with respect to the required torque, a command signal for operating the electric motor 40 as a motor is output, while the output torque of the engine 10 is When there is a margin for the required torque, a command signal for operating this as a generator is output. In addition to this, in the present embodiment, when the engine 10 is started, fuel supply control described later is executed.
  • the motor control circuit 154 converts a direct current from the power storage device (for example, a battery or a capacitor) 160 into a three-phase alternating current, and corresponds a current component of each phase.
  • the electromagnetic coil 44 is supplied.
  • the three-phase alternating current generated by the electromagnetic coil 44 is converted into a direct current and supplied to the power storage device 160.
  • FIG. 2 shows a schematic configuration of the carburetor 60 provided in the engine 10 by a longitudinal section parallel to the central axis of the intake passage.
  • FIG. 3 shows a schematic configuration of the engine 10 by a longitudinal section perpendicular to the central axis Ctr of the crankshaft 12.
  • an air supply passage 102, a scavenging passage 104, and an exhaust passage 106 are formed in the engine 10.
  • one end of each of these passages 102 to 106 communicates with the inside of the cylinder 14 and is opened and closed by the circumferential side surface according to the reciprocating movement of the piston 22.
  • the air supply passage 102 communicates with the cylinder 14 at the intake port P1, and the intake port P1 is positioned below the upper surface of the piston 22 whose upper edge is at the bottom dead center, and the lower edge is at the top dead center. It is set so that it may be located below the lower surface of the piston 22 in the above. As a result, the air supply passage 102 is blocked by the peripheral side surface of the piston 22 when the piston 22 is at the bottom dead center, while the supply passage 102 is below the piston 22 in the process of transition from the middle stroke of the piston 22 to the middle stroke of the lower stroke. Opened, the negative pressure generated in the crankcase 16 is introduced, and the air-fuel mixture is sucked into the crankcase 16.
  • the upward stroke refers to a stroke in which the piston 22 moves from the bottom dead center farthest away from the combustion chamber C to the top dead center closest to the piston 22, and the downward stroke refers to a stroke in which the piston 22 is bottom dead from the top dead center. The process of moving toward a point.
  • the scavenging passage 104 communicates with the crankcase 16 at the scavenging air inlet P21 at one end, and communicates with the cylinder 14 at the scavenging port P22 at the other end to spatially connect the crankcase 16 and the cylinder 14 with each other. ing.
  • the scavenging port P22 is set such that its upper edge is located above the upper surface of the piston 22 at the bottom dead center and its lower edge is located above the lower surface of the piston 22 at the top dead center.
  • the scavenging passage 104 allows the scavenging port P22 to open above the piston 22 at the end of the downward stroke of the piston 22 so that the crankcase 16 and the cylinder 14 communicate with each other.
  • a passage for feeding into the cylinder 14 is formed.
  • the exhaust passage 106 communicates with the inside of the cylinder 14 at the exhaust port P3.
  • the exhaust port P3 is located above the upper surface of the piston 22 whose upper edge is at the bottom dead center, and the lower edge is at the top dead center. It is set to be located above the lower surface of a certain piston 22.
  • the exhaust passage 106 is closed by the peripheral side surface of the piston 22 when the piston 22 is at the top dead center, while in the cylinder 14 before the scavenging port P22 in the period after the middle of the downward stroke of the piston 22. Opening and exhausting the exhaust gas to lower the pressure in the cylinder 14.
  • the crankcase 16 is formed with a pressure transmission passage 16a for introducing the pressure fluctuation generated in the crankcase 16 into the pump drive pressure chamber 72 of the carburetor 60 described below.
  • the pressure transmission passage 16a is formed so as to penetrate the crankcase 16 in a direction perpendicular to the central axis Ctr of the crankshaft 12, and the inside of the crankcase 16 and the pump drive pressure chamber 72 are connected to this pressure. It communicates via the transmission path 16a.
  • the carburetor 60 is formed with a venturi section 62, and the cylinder 14 of the engine 10 is connected to the carburetor 60 on the downstream side of the venturi section 62.
  • An air cleaner (not shown) is attached on the upstream side of the venturi 62.
  • a choke valve 64 is disposed upstream of the venturi section 62, and an air metering valve 66 is rotatably disposed downstream.
  • a pump chamber 70 and a pump drive pressure chamber 72 defined by a diaphragm 68 are formed in the main body wall portion above the venturi portion 62.
  • a fuel storage chamber 76 and an atmospheric chamber 78 defined by a diaphragm 74 are formed in the main body wall portion below the venturi 62, and the pump chamber 70 has an inlet passage 60a in which a check valve v1 is interposed. And communicates with the fuel storage chamber 76 via an intermediate passage 60b in which a check valve v2 is interposed.
  • the pump drive pressure chamber 72 is connected to the pressure transmission passage 16 a of the crankcase 16 through the pressure introduction passage 60 d and communicates with the crankcase 16.
  • the atmospheric chamber 78 is open to the atmosphere.
  • An inflow restricting valve 80 is interposed in the intermediate passage 60b between the pump chamber 70 and the fuel storage chamber 76.
  • the inflow regulating valve 80 is coupled to one side of a lever member 82 that is supported so as to be rotatable about a shaft 82 a with respect to the main body of the carburetor 60.
  • a spring 84 is interposed between the main body of the carburetor 60 and the lever member 82 in a compressed state, and the lever member 82 is biased by the inflow regulating valve 80 so as to close the intermediate passage 60b.
  • the other side of the lever member 82 is coupled to the central portion of the diaphragm 74.
  • the fuel storage chamber 76 communicates with the venturi portion 62 via the outlet passage 60c, and a metering hole h1 for regulating the maximum flow rate of the fuel flowing through the passage 60c is formed at the inlet portion of the outlet passage 60c.
  • a jet hole h2 is formed at the outlet.
  • a fuel control valve 86 is installed in the middle of the outlet passage 60c. The fuel adjustment valve 86 is manually operated by an operator and adjusts the amount of fuel supplied to the engine 10 by the carburetor 60.
  • the diaphragm 68 When the pressure fluctuation in the crankcase 16 is introduced into the pump drive pressure chamber 72 through the pressure passages 16a and 60d, the diaphragm 68 is operated by this pressure fluctuation, and the fuel is sucked into the pump chamber 70 from the fuel tank 98.
  • the fuel in the fuel storage chamber 76 is sucked out of the fuel storage chamber 76 by the negative pressure generated in the venturi section 62, supplied to the venturi section 62 through the outlet passage 60c, and added to the air that has passed through the air cleaner.
  • the amount of fuel added to the air is adjusted by the fuel adjustment valve 86, and the maximum flow rate is regulated by the metering hole h1.
  • the “diaphragm pump” of the carburetor 60 includes a main body upper side wall portion of the carburetor 60 that forms the pump chamber 70, the pump drive pressure chamber 72, the inlet passage 60a, the intermediate passage 60b, and the pressure introduction passage 60d, and the diaphragm 68. And check valves v1 and v2.
  • 3 to 6 show the operation of the engine 10 during normal operation in time series.
  • the piston 22 passes through the bottom dead center and starts moving toward the top dead center (FIG. 3)
  • the scavenging port P22 is closed by the peripheral side surface of the piston 22
  • the inside of the crankcase 16 is exposed to the outside. It becomes a sealed state, and a negative pressure develops in the crankcase 16.
  • the spark plug 34 When reaching the end of the ascending stroke, the spark plug 34 operates near the top dead center, and the compressed air-fuel mixture in the combustion chamber C is ignited.
  • the piston 22 When passing through the top dead center and proceeding to the lowering stroke, the piston 22 is pushed down by the volume expansion of the fuel and rotates the crankshaft 12 via the connecting rod 24. The rotational movement of the crankshaft 12 is transmitted to the drive shaft of the portable work machine, and rotates the cutting blade.
  • FIGS. 7 to 11 show the operation when the engine 10 is started.
  • 7 and 8 show the control for supplying fuel from the fuel tank 98 to the carburetor 60 (hereinafter referred to as “fuel filling control”)
  • FIGS. 9 and 10 show the fuel supply from the carburetor 60 to the engine 10 to form an air-fuel mixture.
  • FIG. 11 shows the control (hereinafter referred to as “starting fuel supply control”) and the control for igniting the air-fuel mixture and starting the engine 10 (hereinafter referred to as “ignition start control”).
  • starting fuel supply control the control for igniting the air-fuel mixture and starting the engine 10
  • a series of controls shown in FIGS. 7 to 11 are executed by the control unit 150 in accordance with the start operation of the portable work machine performed by the worker. Therefore, in this embodiment, the “starting fuel supply device” is configured by the control unit 150.
  • the electric motor 40 that receives the command signal from the control unit 150 rotates the crankshaft 12 alternately in the normal rotation direction and the reverse rotation direction, thereby causing pressure fluctuation in the crankcase 16.
  • the pressure fluctuation is propagated to the pump drive pressure chamber 72 of the carburetor 60, and the diaphragm 68 is operated. As a result, fuel is sucked out of the fuel tank 98 and supplied to the pump chamber 70.
  • crankshaft 12 is rotated in the forward and reverse directions in the range of crank angles Cr1 to Cr2 in which the scavenging port P22 is closed by the peripheral side surface of the piston 22.
  • reciprocation is made between the position of the crank angle Cr1 that brings the piston 22 close to top dead center and the position of the crank angle Cr2 that moves the piston 22 away from top dead center (corresponding to the “first position”).
  • the crank angle Cr2 the crown surface of the piston 22 is located on the top dead center side with respect to the upper edge of the scavenging port P22, and at the crank angle Cr1, the lower surface of the piston 22 is dead with respect to the lower edge of the intake port P1. Located on the point side.
  • the diaphragm 68 of the carburetor 60 is operated by the pressure fluctuation in the crankcase 16 by rotating the crankshaft 12 alternately in the forward and reverse directions within the range of the crank angle Cr1 to Cr2 that closes the scavenging port P22.
  • a negative pressure is applied to the fuel storage chamber 76 through the ejection hole h2, the outlet passage 60c, and the metering hole h1, and the inflow regulating valve 80 is opened.
  • the fuel can be supplied from the fuel tank 98 to the carburetor 60.
  • the supplied fuel is supplied to the fuel storage chamber 76 according to the remaining state of the fuel.
  • the number of reciprocations of the crankshaft 12 in the fuel filling control can be appropriately set according to the residual state of fuel in the carburetor 60. For example, it is adapted to the condition in which the remaining amount of fuel is the smallest in the interior of the carburetor 60 (for example, the fuel storage chamber 76) and the fuel piping from the fuel tank 98 to the carburetor 60.
  • crankshaft 12 when the crankshaft 12 is rotated from the crank angle Cr1 to the position of Cr2, it is rotated until the crown surface of the piston 22 is positioned below the upper edge of the exhaust port P3, and a part of the exhaust port P3 is rotated. Is open.
  • the crankshaft 12 may be rotated in a range up to the crank angle Cr2 'where the crown surface of the piston 22 is located above the upper edge of the exhaust port P3.
  • FIG. 8 shows the piston 22 by a two-dot chain line when the crankshaft 12 is at the crank angle Cr2 '.
  • the electric motor 40 rotates the crankshaft 12 alternately in the forward and reverse directions over the range of the crank angles Cr3 to Cr4 wider than the crank angles Cr1 to Cr2. Then, the pressure fluctuation generated in the crankcase 16 is propagated to the pump drive pressure chamber 72 of the carburetor 60 and is also propagated to the intake passage 102. As a result, the air-fuel mixture that has passed through the carburetor 60 is supplied into the crankcase 16.
  • crankshaft 12 is rotated in the reverse direction to the crank angle Cr3 where the lower surface of the piston 22 is positioned above the lower edge of the intake port P1 and a part of the intake port P1 opens into the crankcase 16.
  • a forward rotation, and the crown surface of the piston 22 is located below the upper edge of the scavenging port P22, and a crank angle Cr4 at which a part of the scavenging port P22 opens into the cylinder 14 is provided.
  • the position of the crank angle Cr4 that opens the scavenging port P22 corresponds to the “third position”, and brings the piston 22 closer to the bottom dead center than at the crank angle Cr2 (first position).
  • the position of the crank angle Cr3 that opens the intake port P1 corresponds to a “second position”, and brings the piston 22 closer to the top dead center than at the crank angle Cr1.
  • crankshaft 12 is rotated in one direction until the intake port P1 is opened, and then rotated in the opposite direction until the scavenging port P22 is opened, whereby the air-fuel mixture is sucked into the crankcase 16.
  • the air-fuel mixture can be supplied from the crankcase 16 into the cylinder 14 through the scavenging passage 104.
  • the electric motor 40 rotates the crankshaft 12 in the reverse direction to the position of the crank angle Cr5 at which the piston 22 reaches a predetermined position before the top dead center.
  • the scavenging port P22 and the exhaust port P3 are closed by the peripheral side surface of the piston 22, and a compressed mixture is formed in the combustion chamber C.
  • the crank angle Cr5 is set to an angle that determines the ignition timing at the start of the engine 10, and when the crankshaft 12 reaches the position of the crank angle Cr5, the spark plug 34 is activated, and the combustion chamber Ignition of the C compressed mixture is performed.
  • the electric motor 40 stops the rotational drive of the crankshaft 12 in synchronization with the ignition.
  • the piston 22 is pushed down from the predetermined position by the volume expansion of the fuel, and the crankshaft 12 starts to rotate forward from the position of the crank angle Cr5 and starts rotating in the forward rotation direction.
  • the electric motor 40 is driven again before the top dead center, and assist torque in the forward direction is generated with respect to the crankshaft 12. You may make it make it. Thereby, the function of the flywheel can be shared by the electric motor 40.
  • the position Cr5 before the top dead center at which the crankshaft 12 is reached is set in correspondence with the ignition timing, and the rotational drive of the electric motor 40 is stopped in synchronization with the ignition.
  • a configuration for example, a rotor position detection circuit
  • a position for rotating the crankshaft 12 at the time of ignition is set in advance, and the electric motor 40 causes the crankshaft 12 to rotate.
  • the spark plug 34 may be operated in synchronization with the rotation of the crankshaft 12 being stopped.
  • the crankshaft 12 is alternately rotated in the forward and reverse directions by the electric motor 40 to cause pressure fluctuation in the crankcase 16, and this pressure fluctuation is applied to the carburetor 60.
  • the diaphragm 68 can be operated, and fuel can be supplied from the fuel tank 98 to the carburetor 60. Therefore, a sufficient amount of fuel can be secured in the carburetor 60 when the engine 10 is started.
  • the air-fuel mixture is supplied into the crankcase 16 through the carburetor 60 by rotating the crankshaft 12 back and forth alternately so that the intake ports P1 and the scavenging ports P22 open alternately. Further, this air-fuel mixture can be supplied into the cylinder 14 through the scavenging passage 104.
  • crankshaft 12 is rotated in the reverse direction to compress the air-fuel mixture in the cylinder 14 and ignited when the crankshaft 12 reaches a position before the top dead center. It becomes possible to utilize the volume expansion force. Therefore, the engine 10 can be reliably started, and the cranking that has been performed by the starter motor or the like is unnecessary, so that the electric motor 40 can be reduced in size and labor can be saved.
  • FIG. 12 shows a schematic configuration of a carburetor 60 that constitutes a fuel supply device according to another embodiment of the present invention, in the same longitudinal section as that of FIG.
  • the supply (filling) of fuel from the fuel tank 98 to the carburetor 60 is realized by the reciprocating rotation of the crankshaft 12, but in the present embodiment, this is realized by the priming pump 90.
  • the configuration other than the priming pump 90 and its periphery is the same as in the previous embodiment.
  • the check valve embodied by the umbrella portion 94a of the umbrella-type valve 94 is inhaled as the volume of the spoid increases. 90a is opened, and the fuel vapor and air in the fuel storage chamber 76 are caused to flow into the spoid 92 through the suction passage 90a. Then, when the operator next crushes the spoid 92, the check valve embodied by the shaft portion 94b of the umbrella valve 94 opens the discharge passage 90b, and the fuel vapor or the like in the spoid 92 is transferred to the fuel tank 98. Reflux. By repeating such an operation, a negative pressure develops in the fuel storage chamber 76, the inflow regulating valve 80 is opened, and fuel is supplied from the fuel tank 98 to the carburetor 60 (fuel storage chamber 76).
  • the control after filling the carburetor 60 with fuel may be the same as in the previous embodiment (starting fuel supply control, ignition starting control). Specifically, after the crankshaft 12 is reciprocated between the crank angle Cr3 position and the crank angle Cr4 position to supply the air-fuel mixture into the cylinder 14, the crankshaft 12 is moved to a position Cr5 before top dead center. Until the compression mixture in the combustion chamber C is ignited.
  • an air-fuel mixture is formed in advance in the cylinder 14 and can be started using the volume expansion force of the fuel. Cranking is not necessary, and the electric motor 40 can be reduced in size and labor.
  • a “diaphragm pump” of the carburetor 60 is configured by the main body upper side wall portion of the carburetor 60, the diaphragm 68, and the check valves v 1 and v 2, and “starting fuel supply” is performed by the control unit 150 and the priming pump 90.
  • Device is configured.
  • the rotation direction of the crankshaft 12 when the piston 22 is brought close to top dead center is defined as the reverse rotation direction
  • the rotation direction when the piston 22 is moved away from it is defined as the normal rotation direction.
  • the forward / reverse rotation direction may be the forward rotation direction when the piston 22 is brought close to the top dead center, and the reverse rotation direction when the piston 22 is moved away. In this case, for example, with respect to the example shown in FIG. 7, the crankshaft 12 reciprocates at a mirror-symmetrical position with respect to the central axis of the cylinder 14.
  • a 4-stroke engine can be used as the engine.
  • the crankshaft when starting the engine, the crankshaft is alternately rotated in the normal rotation direction and the reverse rotation direction in the range of the crank angle (for example, the exhaust stroke) at which the intake valve is closed, and the pressure fluctuation generated in the crankcase is It acts on the diaphragm pump provided in the carburetor. Then, the reciprocating rotation of the crankshaft is continued by changing the reach range of the piston, and after the air-fuel mixture is supplied into the cylinder via the intake port, the crankshaft is reversely rotated to a predetermined position before the compression top dead center. Turn on and ignite.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Means For Warming Up And Starting Carburetors (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
PCT/JP2013/067264 2012-06-29 2013-06-24 Dispositif d'alimentation en combustible destiné à un moteur, et machine-outil portative Ceased WO2014002957A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012-147742 2012-06-29
JP2012147742A JP2015172330A (ja) 2012-06-29 2012-06-29 エンジンの燃料供給装置

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WO2014002957A1 true WO2014002957A1 (fr) 2014-01-03

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02211364A (ja) * 1989-02-08 1990-08-22 Walbro Far East Inc 気化器の始動燃料供給装置
JP2005155392A (ja) * 2003-11-25 2005-06-16 Zama Japan Co Ltd 膜式気化器の始動装置
JP2008019828A (ja) * 2006-07-14 2008-01-31 Kokusan Denki Co Ltd エンジン始動装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02211364A (ja) * 1989-02-08 1990-08-22 Walbro Far East Inc 気化器の始動燃料供給装置
JP2005155392A (ja) * 2003-11-25 2005-06-16 Zama Japan Co Ltd 膜式気化器の始動装置
JP2008019828A (ja) * 2006-07-14 2008-01-31 Kokusan Denki Co Ltd エンジン始動装置

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