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WO2017154783A1 - Internal combustion engine intake device - Google Patents

Internal combustion engine intake device Download PDF

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Publication number
WO2017154783A1
WO2017154783A1 PCT/JP2017/008538 JP2017008538W WO2017154783A1 WO 2017154783 A1 WO2017154783 A1 WO 2017154783A1 JP 2017008538 W JP2017008538 W JP 2017008538W WO 2017154783 A1 WO2017154783 A1 WO 2017154783A1
Authority
WO
WIPO (PCT)
Prior art keywords
intake
intake passage
valve
partition plate
carburetor
Prior art date
Application number
PCT/JP2017/008538
Other languages
French (fr)
Japanese (ja)
Inventor
中村　洋平
一行 高姓
大地 月原
藤久保　誠
秀輝 齋藤
Original Assignee
本田技研工業株式会社
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 本田技研工業株式会社 filed Critical 本田技研工業株式会社
Priority to JP2018504450A priority Critical patent/JP6564523B2/en
Publication of WO2017154783A1 publication Critical patent/WO2017154783A1/en

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Classifications

    • 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
    • F02B31/00—Modifying induction systems for imparting a rotation to the charge in the cylinder
    • F02B31/04—Modifying induction systems for imparting a rotation to the charge in the cylinder by means within the induction channel, e.g. deflectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
    • 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
    • F02M9/00—Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position
    • F02M9/02—Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position having throttling valves, e.g. of piston shape, slidably arranged transversely to the passage
    • F02M9/06—Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position having throttling valves, e.g. of piston shape, slidably arranged transversely to the passage with means for varying cross-sectional area of fuel spray nozzle dependent on throttle position
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to an intake device for an internal combustion engine improved for the generation of tumble flow.
  • a partition plate portion is provided in an intake passage on the downstream side of the on-off valve in the carburetor, and the main passage of the intake passage serving as a passage when the on-off valve is fully opened
  • the intake air flows through the tumble flow path when the load is low, and the open / close valve opens greatly when the load is high.
  • An intake device that allows intake air to flow through both of the paths is described in, for example, Patent Document 1 below.
  • the partition plate part is provided so that it may extend downstream from the inside of a vaporizer, it is necessary to use a dedicated vaporizer, and an existing vaporizer is used. Cannot be diverted.
  • the intake air passing through both the main flow path and the tumble flow path causes a flow collision on the downstream side of the end point of the partition plate portion, and there has been a demand for improvement in the formation of the tumble flow.
  • the present invention has been made in view of the above prior art, and even when the internal combustion engine is at a low load, the intake air easily generates a tumble flow in the combustion chamber, and flows through the main flow channel and the tumble flow channel at a high load of the internal combustion engine. It is an object of the present invention to provide an intake device for an internal combustion engine that can suppress collision of intake air downstream of an intake passage, does not require a dedicated carburetor, and can use an existing carburetor.
  • the top surface of a piston that is slidably fitted in the cylinder bore of the cylinder block and the top surface of the combustion chamber of the cylinder head that faces the same top surface are provided.
  • a combustion chamber is formed, and the cylinder head is formed by extending the intake port and the exhaust port from the intake valve port and the exhaust valve port opened in the ceiling surface of the combustion chamber while curving in a direction away from each other,
  • An inlet pipe is connected to the intake port to form a continuous intake passage, and a carburetor is connected to the upstream side of the inlet pipe. The carburetor opens and closes the flow path across the flow path inside the intake pipe.
  • a second intake passage corresponding to an inner wall portion of the flow path, the tip of which is pressed when the open / close valve of the carburetor is closed, in the flow direction of the intake air.
  • An intake device for an internal combustion engine is provided, wherein the end portion is at a position corresponding to the displacement direction of the on-off valve.
  • the upstream end of the partition plate is spaced downstream from the connection between the inlet pipe and the vaporizer.
  • the partition plate portion has a downstream end portion integrally formed by bending toward the cylinder block side in the cylinder head, and the second intake air.
  • the passage has a terminal end formed to face the combustion chamber ceiling surface of the cylinder head.
  • the intake port and the inlet pipe are connected via an insulator
  • the partition plate portion includes an inlet pipe side partition plate portion, and an intake port side partition plate portion.
  • an insulator region partition plate portion, the downstream end portion of the inlet pipe side partition plate portion is formed thicker than the upstream end portion (85Ca) of the insulator region partition plate portion, and the insulator region partition plate portion The downstream end is formed thicker than the upstream end of the intake port side partition plate.
  • a notch that is recessed downstream is formed at the upstream end of the partition plate.
  • both end portions of the upstream end portion of the partition plate portion are bent toward a valve opening direction of the on-off valve of the carburetor.
  • the combustion chamber is provided between the top surface of the piston slidably fitted in the cylinder bore of the cylinder block and the combustion chamber ceiling surface of the cylinder head facing the same top surface.
  • the cylinder head is formed to extend from the intake valve port and the exhaust valve port opened in the ceiling surface of the combustion chamber while curving in a direction in which the intake port and the exhaust port are separated from each other.
  • a pipe is connected to form a continuous intake passage, and a carburetor is connected to the upstream side of the inlet pipe, and the carburetor can be displaced so as to open and close the flow path across the internal flow path.
  • the radial width of the intake passage of the inlet pipe includes the radial width of the first intake passage and the radial width of the second intake passage, and the radial width of the intake passage of the inlet pipe. Is larger than the open / close width of the open / close valve of the vaporizer.
  • the open / close width of the open / close valve of the carburetor is formed to be substantially the same as the radial width of the first intake passage.
  • the intake device for an internal combustion engine of the present invention when the internal combustion engine is under a low load, intake air from the opening / closing valve having a small opening angle easily flows into the second intake passage along the flow passage wall of the carburetor. A tumble flow can be easily generated in the room. Further, when the internal combustion engine is at a high load, the opening degree of the carburetor on / off valve increases, and most of the intake air flows through the first intake passage, so that the flow rate flowing through the second intake passage can be reduced, and the first intake air is reduced. It is possible to suppress the intake air flowing through the passage and the second intake passage from colliding downstream of the intake passage.
  • the carburetor is disposed upstream of the separation point of the first intake passage and the second intake passage in the inlet pipe, there is no need to provide a dedicated carburetor having a separation flow path, and an existing carburetor is provided. Can be diverted.
  • the upstream end portion of the partition plate portion is spaced downstream from the connection portion between the inlet pipe and the carburetor, thereby obtaining a desired tumble ratio at a low load of the internal combustion engine.
  • the internal combustion engine is at a high load, the flow rate of the intake air flowing into the first intake passage can be ensured.
  • a downward slope portion is formed that inclines in the direction away from the center of the intake air flow toward the second intake passage in the intake air flow direction.
  • the partition plate portion has a downstream end portion integrally formed by bending toward the cylinder block side in the cylinder head, and the second intake passage is formed in the ceiling of the combustion chamber of the cylinder head.
  • the insulator-side partition plate portion connected to the downstream side of the inlet pipe-side partition plate portion is thin, and the downstream of the insulator-side partition plate portion. Since the intake port side partition plate connected to the side is thin and is formed in a stepped shape in which the thickness of each partition plate at the joint decreases according to the flow of intake air, it interferes with the flow of intake air flowing through the intake passage. Can be suppressed. Further, even when an assembly error occurs, the assembly error can be absorbed by forming the step.
  • a notch recessed downstream is formed at the upstream end of the partition plate portion, so that the area where the intake air flowing into the intake passage hits the partition plate gradually increases. In this way, changes in pressure and speed can be moderated and flow loss can be reduced.
  • both end portions of the upstream end portion of the partition plate portion are bent toward the valve opening direction of the on-off valve of the carburetor.
  • the intake air that flows into the intake passage when the internal combustion engine is under a low load flows from the lower side of the intake passage to the upper side of both sides and flows in a fan shape, so it bends toward the opening direction of the open / close valve of the carburetor
  • By providing both side end portions of the partition plate portion to be received it is possible to receive intake air flowing in a fan shape and easily guide it to the second air passage.
  • a notch that is recessed downstream is formed at the upstream end of the partition plate portion, the flow of the intake air when the carburetor on-off valve is fully opened flows through the center of the notch recess without any problem.
  • the radial width of the intake passage of the inlet pipe includes the radial width of the first intake passage and the radial width of the second intake passage, and the radial direction of the intake passage of the inlet pipe. Is larger than the opening / closing width of the on / off valve of the carburetor, so that when the internal combustion engine is under a low load, intake air from the on / off valve having a small opening degree flows into the second intake passage along the channel wall of the carburetor. It becomes easy to flow, and it can make it easy to generate a tumble flow in the combustion chamber.
  • the opening degree of the carburetor on / off valve increases, and most of the intake air flows through the first intake passage, so that the flow rate flowing through the second intake passage can be reduced, and the first intake air is reduced. It is possible to suppress the intake air flowing through the passage and the second intake passage from colliding downstream of the intake passage.
  • the opening / closing width of the opening / closing valve of the carburetor is formed to be substantially the same as the radial width of the first intake passage, so that the air flowing into the intake passage at the time of high load of the internal combustion engine Can be easily flown into the first intake passage, and the amount of intake air flowing through the first intake passage can be easily secured when the internal combustion engine is at a high load.
  • FIG. 1 is a right side view of a scooter type motorcycle equipped with a power unit including an intake device for an internal combustion engine according to an embodiment of the present invention. It is the rear right side surface of the motorcycle with the body cover removed.
  • FIG. 3 is a side cross-sectional view of a front portion of a power unit having the same orientation as shown in FIG. 2, that is, a portion of an internal combustion engine. It is a principal part enlarged view of FIG. Part (a) is a cross-sectional view of Modification 1 of the inlet pipe showing only the inlet pipe of FIG. 4, and part (b) is a view taken along the line bb in part (a). It is sectional drawing of the modification 2 of the inlet pipe which takes out only the inlet pipe of FIG. 4 like the (a) part of FIG.
  • an intake device for an internal combustion engine will be described based on the drawings. Note that the directions such as front, rear, left, right, up, down, etc. in the description and claims of the present specification are the same as those of a vehicle equipped with an internal combustion engine equipped with an intake device according to this embodiment.
  • the vehicle is a small vehicle, for example, a scooter type motorcycle.
  • an arrow FR indicates the front of the vehicle
  • LH indicates the left side of the vehicle
  • RH indicates the right side of the vehicle
  • UP indicates the upper side of the vehicle.
  • FIG. 1 shows a right side surface of a scooter type motorcycle (hereinafter simply referred to as “motorcycle”) 1 equipped with a power unit including an intake device for an internal combustion engine of the present embodiment.
  • a vehicle body front portion 1A and a vehicle body rear portion 1B are connected via a low floor portion 1C, and a vehicle body frame 2 forming a skeleton of the vehicle body is generally composed of a down tube 21 and a main pipe 22 (see FIG. 2). ). That is, the down tube 21 extends downward from the head pipe 20 of the vehicle body front portion 1A, and the down tube 21 is bent horizontally at the lower end and extends rearward below the floor portion 1C, as shown in FIG.
  • a pair of left and right main pipes 22 are connected via a connecting frame 23 arranged in the vehicle width direction in FIG. 2, and the main pipe 22 rises obliquely rearward from the connecting frame 23 and bends so that the inclination is loosened in the middle. It extends backward.
  • a handle 13 is provided above and supported by the head pipe 20, a front fork 14 extends downward, and a front wheel 15 is supported at the lower end thereof.
  • the rear right side surface of the motorcycle 1 with the vehicle body cover 12 removed shows a bracket 24 projecting near the lower end of the inclined portion of the main pipe 22, and the power unit 3 is connected to the bracket 24 via the link member 25.
  • the power unit 3 is a single-cylinder four-stroke cycle air-cooled internal combustion engine (hereinafter simply referred to as “internal combustion engine”) 30, and the power unit 3 includes a crankshaft at the front of the power unit case 50 constituting the crankcase 50 a.
  • the parts are connected via a link member 25 attached to the bracket 24 of the main pipe 22.
  • the power unit 3 includes an internal combustion engine 30 that is largely inclined forward substantially horizontally at a front portion of the power unit case 50 that constitutes the crankcase portion 50a, and a cylinder block 31, a cylinder head 32, and a cylinder head cover 33 that constitute the internal combustion engine 30 are provided. It is concluded so that it may be piled up sequentially.
  • a power transmission case portion 55 having a belt type continuously variable transmission or the like extends integrally from the crankcase portion 50a to the rear left side, and a rear axle 56 which is an output shaft of the power unit 3 is provided at the rear portion thereof. Is attached.
  • a rear cushion (not shown) is interposed between the power transmission case 55 at the rear of the power unit 3 and the rear of the main pipe 22.
  • the inlet pipe 6 extends from the upper part of the cylinder head 32 inclined largely forward of the internal combustion engine 30, curves backward, and is connected to the inlet pipe 6. Is located above the cylinder block 31, and an air cleaner device (not shown) is disposed above the power transmission case 55 in the carburetor 7 via a connecting tube 37.
  • the exhaust pipe 38 extending downward from the lower part of the cylinder head 32 is bent rearward, is biased to the right and extends rearward, and is connected to the muffler 39 on the right side of the rear wheel 16.
  • FIG. 3 is a side sectional view of the front portion of the power unit 3, that is, the portion of the internal combustion engine 30, with the same orientation as shown in FIG.
  • the internal combustion engine 30 has a piston 34 that reciprocates in a cylinder bore 31 a of a cylinder block 31, and a connecting rod 35 connects the piston 34 and a crank pin 51 a of a crankshaft 51.
  • a combustion chamber 36 is formed between the top surface 34a of the piston 34 slidably fitted in the cylinder bore 31a of the cylinder block 31 and the combustion chamber ceiling surface 32a of the cylinder head 32 opposed to the top surface 34a.
  • the internal combustion engine 30 employs a SOHC type two-valve system, and the valve mechanism 9 is provided in the cylinder head 32.
  • the cylinder head 32 is covered with a cylinder head cover 33 so as to cover the valve mechanism 9.
  • an endless cam chain (not shown) is provided on one side of the crankcase 50a, the cylinder block 31, and the cylinder head 32 in the direction of the crankshaft 51 (not shown).
  • the camshaft chamber is installed between the camshaft 91 and the crankshaft 51 through the cam chain chamber, and the camshaft 91 rotates at a half rotational speed in synchronization with the crankshaft 51.
  • An ignition plug (not shown) is inserted into the combustion chamber 36 from the opposite side of the cam chain chamber (the other side in the direction of the crankshaft 51) in the cylinder head 32.
  • the intake port 42 and the exhaust valve port 41 opened in the combustion chamber ceiling surface 32 a
  • the exhaust ports 43 are formed so as to extend while being curved away from each other in the vertical direction.
  • the upstream end of the intake port 42 is connected to the inlet pipe 6 toward the upper side of the cylinder head 32 to form a continuous intake passage 80, and the carburetor 7 is connected to the upstream side of the inlet pipe 6.
  • the downstream end of the exhaust port 43 is connected to the exhaust pipe 38 toward the lower side of the cylinder head 32.
  • a cylindrical valve guide 44 is integrally fitted to the curved outer wall portion of the intake port 42 in the cylinder head 32, and the intake valve 46 slidably supported by the valve guide 44 faces the combustion chamber 36 of the intake port 42. Open and close the intake valve port 40.
  • an exhaust valve 47 slidably supported by a valve guide 45 fitted integrally with the curved outer wall portion of the exhaust port 43 in the cylinder head 32 has an exhaust valve port 41 facing the combustion chamber 36 of the exhaust port 43. Open and close.
  • the intake valve 46 and the exhaust valve 47 are urged upward by the valve spring 48 so that the umbrella portions 46a and 47a both close the intake valve port 40 and the exhaust valve port 41 facing the combustion chamber 36.
  • the intake valve 92 and the exhaust rocker arm 95 that abuts and swings against the intake cam 92 and the exhaust cam 93 of the camshaft 91 push down the stem ends 46b and 47b of the intake valve 46 and the exhaust valve 47, and the intake valve at a predetermined timing.
  • 46 and the exhaust valve 47 are opened, and the intake port 42 and the combustion chamber 36 communicate with each other, and the exhaust port 43 and the combustion chamber 36 communicate with each other to perform intake and exhaust at a predetermined timing.
  • the intake passage 80 for providing a tumble flow of the fuel / air mixture in the combustion chamber 36 that is, longitudinal rotation.
  • the intake passage 80 is partitioned into a first intake passage 80A and a second intake passage 80B by a partition plate portion 85 that extends from the inlet pipe 6 to the intake port 42.
  • the second intake passage 80B is a lower lower passage close to the lower end 71a when the on-off valve 71 of the carburetor 7 is closed, and serves as a tumble passage.
  • the first intake passage 80A is an upper upper passage excluding the second intake passage 80B, and is partitioned into a first intake passage 80A serving as a main flow passage.
  • the flow path 70 of the vaporizer 7 is connected to the connecting tube 37 on the upstream side, and the downstream end 70a is connected to the inlet 75 via the insulator 75 as shown in FIG.
  • an on-off valve 71 formed by a venturi piston of the venturi 72 is vertically moved across the flow path 70. Displaceable.
  • the carburetor 7 is provided with a throttle valve 73 on the upstream side of the on-off valve 71 to constitute a negative pressure operation type carburetor.
  • the lower end 71a that is the tip of the on-off valve 71 is the upstream end of the second intake passage 80B that is partitioned from the first intake passage 80A by the partition plate 85.
  • the lower end 71a constituting the tip of the on-off valve 71 is a bottom portion 70b as a channel inner wall portion at a position corresponding to the second intake passage 80B, which is a tumble channel, in the flow direction when the on-off valve 71 is closed. Pressed against.
  • the on-off valve 71 is pressed against the bottom 70 b that is the lower inner wall of the flow path 70 as described above to close the flow path 70, but when the on-off valve 71 is opened, the venturi section 72 The fuel is sucked out to be mixed with the intake air, and sent from the flow path 70 on the downstream side of the carburetor 7 to the inlet pipe 6, that is, to the intake passage 80.
  • a mixture of intake air and fuel (hereinafter simply referred to as “intake air”) flowing into the intake passage when the internal combustion engine is under low load is a lower end 71a of the opening / closing valve 71 having a small opening and a bottom portion 70b of the flow path 70.
  • intake air A mixture of intake air and fuel flowing into the intake passage when the internal combustion engine is under low load is a lower end 71a of the opening / closing valve 71 having a small opening and a bottom portion 70b of the flow path 70.
  • the air flows out in a fan shape along the bottom 70b from between the air
  • the opening / closing valve 71 is pressed against the bottom 70b of the flow path 70 when the valve is closed, and the bottom 70b is connected to the upstream end 85a of the partition plate 85 with respect to the vertical movement direction of the opening / closing valve 71. It is in a substantially corresponding position.
  • the vaporizer 7 has a downstream end 70 a of the flow path 70 connected to an upstream end 80 a of the intake passage 80 in the inlet pipe 6 via an insulator 75. That is, the carburetor 7 is disposed upstream of the separation point between the first intake passage 80A and the second intake passage 80B of the intake passage 80. Accordingly, the bottom portion 80Ba of the second intake passage 80B shown in FIG. 4 is disposed at a position lower than the bottom portion 70b of the flow path 70 on the downstream side of the carburetor 7 shown in FIG.
  • the upstream end bottom portion 80Bb shown in FIG. 4 forms a downward slope portion 81 that gradually falls from the height of the bottom portion 70b shown in FIG.
  • the inner wall of the intake passage 80 is lowered in the downward slope portion 81 from the bottom portion 70b of the flow path 70 of the carburetor 7 to the bottom portion 80Ba of the second intake passage 80B through the upstream end side bottom portion 80Bb. It is formed in a direction away from the center of the flow.
  • the slope at the upstream end bottom portion 80Bb of the second intake passage 80B is the largest descending slope.
  • the intake air when the internal combustion engine 30 is at a low load, the intake air easily flows into the second intake passage 80B, and a tumble flow can be easily generated in the combustion chamber 36. Further, when the internal combustion engine 30 is at a high load, the opening / closing valve 71 of the carburetor 7 increases, and most of the intake air flows through the first intake passage 80A, so that the flow rate flowing through the second intake passage 80B is reduced. In addition, the intake air flowing through the first intake passage 80A and the second intake passage 80B can be prevented from colliding downstream of the intake passage 80, that is, downstream of the intake port 42.
  • the carburetor 7 is disposed upstream of the separation point between the first intake passage 80A and the second intake passage, there is no need to provide a dedicated carburetor having a separation flow path for intake air, and an existing carburetor can be used. Can be diverted.
  • the descending slope portion 81 may be provided in either the inlet pipe 6 or the insulator 75, or may be provided in the vaporizer 7.
  • the vaporizer 7 is also formed with a falling slope portion 74 at the bottom portion 70b of the flow path 70 on the downstream side of the on-off valve 71 in FIG. That is, since the slopes 74 and 81 are formed on the downstream side of the on-off valve 71 of the carburetor 7, the second intake passage 80B can be formed downward. 2.
  • the intake air can be easily guided to the intake passage 80B, and a tumble flow can be easily generated in the combustion chamber.
  • the upstream end portion 85a of the partition plate portion 85 is spaced downstream from the connection portion between the inlet pipe 6 and the carburetor 7, so that when the internal combustion engine 30 is under a low load, the road wall extends to the second intake passage 80B.
  • the desired amount of tumble ratio can be obtained and the flow rate of the intake air flowing into the first intake passage 80B can be ensured when the internal combustion engine is under a high load.
  • the downstream end 85b of the partition plate 85 is located in the intake port 42 of the cylinder head 32, and the downstream end 85b is located on the cylinder block 31 side in the cylinder head 32.
  • the end 80Bc of the second intake passage 80B is formed so as to face the combustion chamber ceiling surface 32a of the cylinder head 32. For this reason, the intake air flowing through the second intake passage 80B can flow into the cylinder bore 31a after passing over the umbrella portion 46a of the intake valve 46, as indicated by the small arrows in FIG. Tumble flow can be easily generated in the chamber 36.
  • the intake port 42 and the inlet pipe 6 are connected via an insulator 60, and the partition plate portion 85 includes an inlet pipe side partition plate portion 85A, an intake port side partition plate portion 85B, and an insulator.
  • An area partition plate portion 85C is provided.
  • the downstream end 85Ab of the inlet pipe side partition plate 85A is formed thicker than the upstream end 85Ca of the insulator region partition plate 85C, and the downstream end 85Cb of the insulator region partition plate 85C is on the intake port side. It is formed thicker than the upstream end 85Ba of the partition plate 85B.
  • the insulator region partition plate portion 85C connected to the downstream side of the inlet pipe side partition plate portion 85A is thin, and the downstream of the insulator region partition plate portion 85C. Since the intake port side partition plate portion 85B connected to the side is thin and formed in a stepped shape in which the thickness of each partition plate portion 85A, 85C, 85B in the joint portion decreases according to the flow of intake air, the intake air flowing through the intake passage 80 Interference with the flow can be suppressed. Further, even when an assembly error occurs, the assembly error can be absorbed by forming the step.
  • the radial width W1 of the intake passage 80 of the inlet pipe 6 is equal to the radial width W2 of the first intake passage 80A and the radial width W3 of the second intake passage 80B.
  • the radial width W1 of the intake passage 80 of the inlet pipe 6 is formed larger than the open / close width W4 of the open / close valve 71 of the carburetor 7. Therefore, when the internal combustion engine 30 is under a low load, the intake air from the opening / closing valve 71 having a small opening is likely to flow along the wall of the bottom 70b of the flow path 70 of the carburetor 7 into the second intake passage 80B. Tumble flow can be easily generated in 36.
  • the opening degree of the on-off valve 71 of the carburetor 7 is increased, and most of the intake air flows through the first intake passage 80A. Therefore, the flow rate flowing through the second intake passage 80B can be reduced, and the intake air flowing through the first intake passage 880A and the second intake passage 80B can be prevented from colliding downstream of the intake passage 80.
  • the opening / closing width W4 of the opening / closing valve 71 of the carburetor 7 is formed substantially the same as the radial width W2 of the first intake passage 80A, the opening / closing width of the opening / closing valve 71 of the carburetor 7 and the first intake air.
  • the radial width of the passage 80A substantially the same, the air flowing into the intake passage 80 can easily flow into the first intake passage 80A when the internal combustion engine 30 is heavily loaded. It becomes easy to secure the amount of intake air flowing through the first intake passage 80A.
  • FIG. 5 (a) is a cross-sectional view of Modification 1 of the inlet pipe 6 showing only the inlet pipe 6 of FIG. 4, and FIG. 5 (b) is a cross-sectional view taken along line bb in FIG. 5 (a). It is an arrow view.
  • the upstream end 85a of the partition plate 85 that is, the upstream end 85Aa of the inlet pipe side partition 85A is as described in the above embodiment.
  • the end portion is not planar, and a notch 87 is formed to be recessed downstream.
  • the shape of the notch 87 may be the V shape shown in the figure, or may be a U shape. By doing so, it is possible to gradually increase the area where the intake air flowing into the intake passage 80 hits the partition plate portion 85, to moderate changes in pressure and speed, and to reduce flow loss.
  • FIG. 6 is a sectional view of Modification 2 of the inlet pipe 6 in which only the inlet pipe 6 of FIG. 4 is taken out, similar to the part (a) of FIG. 5, and in the vicinity of the upstream end 6 a of the inlet pipe 6. Show only.
  • both end portions 88 of the upstream end portion 85a of the partition plate portion 85 have a rising 89 that is bent upward. That is, the rising 89 is in the opening direction of the on-off valve 71 of the carburetor 7.
  • FIG. 6 also shows the feature of the first modified example, in which the upstream end 85a of the partition plate 85 is also provided with a notch 87 recessed downstream, as in the above-described embodiment. Further, the upstream end 85a of the partition plate 85 may be formed in a straight line and not provided with the notch 87.
  • the intake air flowing into the intake passage 80 when the internal combustion engine 30 is under a low load flows from the lower side of the intake passage 80 to the upper side of both sides and flows in a fan shape.
  • By providing the both end portions 88 it is possible to receive the intake air flowing in a fan shape and easily guide it to the second air passage 80A.
  • the notch 87 that is recessed downstream is formed in the upstream end 85a of the partition plate portion 85, the feature of the first modification is also provided, and the central portion of the notch recess is opened and closed. The flow of the intake air when the valve 71 is fully opened can flow without any trouble.
  • the aspects of the present invention are not limited to the above-described embodiments, and it is needless to say that the present invention includes those implemented in various aspects within the scope of the gist of the present invention.
  • the power unit having the internal combustion engine in which the cylinder axis X is tilted substantially horizontally and forward has been described with respect to the left and right arrangements shown in the figure.
  • the vehicle, power unit, different types of the internal combustion engine, Even those having different left and right arrangements are included in the present invention within the scope of the gist of the invention.
  • Inlet pipe side partition plate portion 85Aa ... Upstream end portion, 85Ab ... Downstream end portion, 85B ... Intake port side partition plate portion, 85Ba ... Upstream side end portion, 85C ... Insulator side partition plate portion, 85Ca ... Upstream side End portion, 85Cb ... downstream end portion, 87 ... notch, 88 ... side end portion, 89 ... rising, X ... cylinder shaft, W1 ... radial width of intake passage 80, W2 ... first intake passage 80A Width in radial direction, W3: Width in radial direction of second intake passage 80B, W4: Width of opening / closing valve 71 of carburetor 7

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Abstract

In the present invention, an intake port 42 and an exhaust port 43 are formed so as to extend from a combustion chamber 36 of an internal combustion engine in mutually separating directions, and an intake passage 80 is formed by connecting an inlet pipe 6 to the intake port 42. A carburetor 7 is connected to an upstream-side of the inlet pipe 6, and a partition plate part 85 of the intake passage 80 partitions the intake passage 80 into a second intake passage 80B that is close to a lower end 71a of an opening/closing valve 71 of the carburetor 7, the lower end 71a being a leading end when the opening/closing valve 71 is closed, and a first intake passage 80A that is the part of the intake passage 80 excluding the second intake passage 80B. The carburetor 7 is connected to an upstream end 80a of the intake passage 80; and an inner wall part 70b of the carburetor 7, against which the leading end 71a of the opening/closing valve 71 of the carburetor 7 is pressed when the opening/closing valve 71 is closed, and an upstream end 85a of the partition plate part 85 are disposed at positions corresponding to an intake flow direction with respect to a displacement direction of the opening/closing valve 71. Due to this configuration, tumble flow is readily generated inside the combustion chamber when the load is low, the collision of intake air in a downstream part of the intake passage can be suppressed, and an existing carburetor can be used.

Description

内燃機関の吸気装置Intake device for internal combustion engine
　本発明は、タンブル流の発生のため改善された内燃機関の吸気装置に関する。 The present invention relates to an intake device for an internal combustion engine improved for the generation of tumble flow.
　従来、内燃機関の燃焼室内においてタンブル流を発生させるために、気化器において開閉弁の下流側の吸気通路に仕切板部を設けて、開閉弁の全開時の流路となる吸気通路の主流路から仕切って、低負荷時の開閉弁の開弁時開口に合わせたタンブル流路を形成し、低負荷時には吸入空気をタンブル流路に流し、高負荷時には開閉弁が大きく開き主流路とタンブル流路の両方に吸入空気を流すようにした吸気装置が、例えば下記特許文献１に記載されている。
　ところで、下記特許文献１に示されるものでは、仕切板部が気化器内から下流側に延在するように設けられているため、専用の気化器を使用する必要があり、既存の気化器を流用することができない。
　また、高負荷時には主流路とタンブル流路の両方を通った吸入空気が仕切板部の終点下流側で流れの衝突を起こすこととなり、タンブル流の形成上改善が求められていた。 Conventionally, in order to generate a tumble flow in a combustion chamber of an internal combustion engine, a partition plate portion is provided in an intake passage on the downstream side of the on-off valve in the carburetor, and the main passage of the intake passage serving as a passage when the on-off valve is fully opened To form a tumble flow path that matches the opening of the open / close valve when the load is low.The intake air flows through the tumble flow path when the load is low, and the open / close valve opens greatly when the load is high. An intake device that allows intake air to flow through both of the paths is described in, for example, Patent Document 1 below.
By the way, in what is shown by the following patent document 1, since the partition plate part is provided so that it may extend downstream from the inside of a vaporizer, it is necessary to use a dedicated vaporizer, and an existing vaporizer is used. Cannot be diverted.
In addition, when the load is high, the intake air passing through both the main flow path and the tumble flow path causes a flow collision on the downstream side of the end point of the partition plate portion, and there has been a demand for improvement in the formation of the tumble flow.
日本国特開平１１－２１０４７８号公報（図１、６、１１）Japanese Patent Laid-Open No. 11-210478 (FIGS. 1, 6, and 11)
　本発明は上記従来技術に鑑みなされたものであり、内燃機関の低負荷時でも、吸入空気が燃焼室内にタンブル流を発生しやすく、内燃機関の高負荷時において主流路とタンブル流路を流れる吸入空気が吸気通路の下流で衝突することを抑制でき、専用の気化器を設ける必要がなく、既存の気化器を流用することができる内燃機関の吸気装置を提供することを課題とする。 The present invention has been made in view of the above prior art, and even when the internal combustion engine is at a low load, the intake air easily generates a tumble flow in the combustion chamber, and flows through the main flow channel and the tumble flow channel at a high load of the internal combustion engine. It is an object of the present invention to provide an intake device for an internal combustion engine that can suppress collision of intake air downstream of an intake passage, does not require a dedicated carburetor, and can use an existing carburetor.
　上記の課題を解決するために、本発明によれば、シリンダブロックのシリンダボア内を摺動自在に嵌合されるピストンの頂面と同頂面が対向するシリンダヘッドの燃焼室天井面との間に燃焼室が構成され 、前記シリンダヘッドには、前記燃焼室天井面に開口した吸気弁口と排気弁口から各々吸気ポートと排気ポートが互いに離れる方向に湾曲しながら延出して形成され、前記吸気ポートにインレットパイプが接続されて連続した吸気通路が構成され、前記インレットパイプの上流側に気化器が接続され、該気化器は、その内部の流路を横切って該流路を開閉するように変位可能の開閉弁を備え、前記吸気通路が、前記気化器の開閉弁の閉弁時にその先端が押し付けられる前記流路の内壁部に吸気の流れ方向で対応する第２吸気通路と、同第２吸気通路を除く第１吸気通路とを仕切る仕切板部を有する内燃機関の吸気装置において、
　前記気化器は、前記吸気通路の上流側端部に接続され、前記気化器の開閉弁の閉弁時に、該開閉弁の先端が押し付けられる前記流路の内壁部と前記仕切板部の上流側端部とが、前記開閉弁の変位方向に関して対応する位置にあることを特徴とする内燃機関の吸気装置が提供される。 In order to solve the above-described problems, according to the present invention, the top surface of a piston that is slidably fitted in the cylinder bore of the cylinder block and the top surface of the combustion chamber of the cylinder head that faces the same top surface are provided. A combustion chamber is formed, and the cylinder head is formed by extending the intake port and the exhaust port from the intake valve port and the exhaust valve port opened in the ceiling surface of the combustion chamber while curving in a direction away from each other, An inlet pipe is connected to the intake port to form a continuous intake passage, and a carburetor is connected to the upstream side of the inlet pipe. The carburetor opens and closes the flow path across the flow path inside the intake pipe. And a second intake passage corresponding to an inner wall portion of the flow path, the tip of which is pressed when the open / close valve of the carburetor is closed, in the flow direction of the intake air. Second In the intake device for an internal combustion engine having a partition plate portion that partitions the first intake passage excluding the intake passage,
The carburetor is connected to an upstream end portion of the intake passage, and when the carburetor on-off valve is closed, the inner wall portion of the flow path and the upstream side of the partition plate portion are pressed against the tip of the on-off valve. An intake device for an internal combustion engine is provided, wherein the end portion is at a position corresponding to the displacement direction of the on-off valve.
　本発明の好適な実施形態では、前記仕切板部の上流側端部は、前記インレットパイプと前記気化器の接続部から下流側に離間している。 In a preferred embodiment of the present invention, the upstream end of the partition plate is spaced downstream from the connection between the inlet pipe and the vaporizer.
　本発明の好適な実施形態によれば、前記気化器の前記開閉弁の下流側で、前記吸気の流れ方向で前記第２吸気通路へ向かって、吸気の流れの中心から該中心を離れる方向に傾斜する下がりスロープ部が形成される。 According to a preferred embodiment of the present invention, on the downstream side of the on-off valve of the carburetor, in a direction away from the center of the flow of intake air toward the second intake passage in the flow direction of the intake air. An inclined down slope portion is formed.
　本発明の好適な他の実施形態によれば、前記仕切板部は、前記シリンダヘッドにおいて前記シリンダブロック側に向けて屈曲して一体に形成された下流側端部を有し、前記第２吸気通路は、前記シリンダヘッドの前記燃焼室天井面を指向するように形成された終端を有する。 According to another preferred embodiment of the present invention, the partition plate portion has a downstream end portion integrally formed by bending toward the cylinder block side in the cylinder head, and the second intake air. The passage has a terminal end formed to face the combustion chamber ceiling surface of the cylinder head.
　本発明の好適なさらに他の実施形態によれば、前記吸気ポートと前記インレットパイプは、インシュレータを介して接続され、前記仕切板部は、インレットパイプ側仕切板部と、吸気ポート側仕切板部と、インシュレータ領域仕切板部とを備え、前記インレットパイプ側仕切板部の下流側端部は、前記インシュレータ領域仕切板の上流側端部(85Ｃa)より厚く形成され、前記インシュレータ領域仕切板部の下流側端部は、前記吸気ポート側仕切板部の上流側端部より厚く形成される。 According to still another preferred embodiment of the present invention, the intake port and the inlet pipe are connected via an insulator, and the partition plate portion includes an inlet pipe side partition plate portion, and an intake port side partition plate portion. And an insulator region partition plate portion, the downstream end portion of the inlet pipe side partition plate portion is formed thicker than the upstream end portion (85Ca) of the insulator region partition plate portion, and the insulator region partition plate portion The downstream end is formed thicker than the upstream end of the intake port side partition plate.
　本発明の好適な実施形態によれば、前記仕切板部の前記上流側端部に、下流側に凹む切り欠きが形成される。 According to a preferred embodiment of the present invention, a notch that is recessed downstream is formed at the upstream end of the partition plate.
　本発明の好適な他の実施形態によれば、前記仕切板部の前記上流側端部の両側端部が、前記気化器の開閉弁の開弁方向に向かって屈曲される。 According to another preferred embodiment of the present invention, both end portions of the upstream end portion of the partition plate portion are bent toward a valve opening direction of the on-off valve of the carburetor.
　本発明の好適な実施形態によれば、シリンダブロックのシリンダボア内を摺動自在に嵌合されるピストンの頂面と同頂面が対向するシリンダヘッドの燃焼室天井面との間に燃焼室が構成され 、前記シリンダヘッドには、前記燃焼室天井面に開口した吸気弁口と排気弁口から各々吸気ポートと排気ポートが互いに離れる方向に湾曲しながら延出して形成され、前記吸気ポートにインレットパイプが接続されて連続した吸気通路が構成され、前記インレットパイプの上流側に、気化器が接続され、該気化器は、その内部の流路を横切って該流路を開閉するように変位可能の開閉弁を備え、前記吸気通路が、前記気化器の開閉弁の閉弁時にその先端が押し付けられる前記流路の内壁部に吸気の流れ方向で対応する第２吸気通路と、同第２吸気通路を除く第１吸気通路とを仕切る仕切板部を有する内燃機関の吸気装置において、
　前記インレットパイプの前記吸気通路の径方向の幅は、前記第１吸気通路の径方向の幅と前記第２吸気通路の径方向の幅を含み、前記インレットパイプの前記吸気通路の径方向の幅は、前記気化器の開閉弁の開閉幅より大きくされる。 According to a preferred embodiment of the present invention, the combustion chamber is provided between the top surface of the piston slidably fitted in the cylinder bore of the cylinder block and the combustion chamber ceiling surface of the cylinder head facing the same top surface. The cylinder head is formed to extend from the intake valve port and the exhaust valve port opened in the ceiling surface of the combustion chamber while curving in a direction in which the intake port and the exhaust port are separated from each other. A pipe is connected to form a continuous intake passage, and a carburetor is connected to the upstream side of the inlet pipe, and the carburetor can be displaced so as to open and close the flow path across the internal flow path. A second intake passage corresponding to an inner wall portion of the flow path, the tip of which is pressed when the open / close valve of the carburetor is closed, in the flow direction of the intake air. The passage In the intake device for an internal combustion engine having a partition plate portion that partitions the first intake passage except
The radial width of the intake passage of the inlet pipe includes the radial width of the first intake passage and the radial width of the second intake passage, and the radial width of the intake passage of the inlet pipe. Is larger than the open / close width of the open / close valve of the vaporizer.
　本発明の一実施形態によれば、前記気化器の前記開閉弁の開閉幅は、前記第１吸気通路の径方向の幅と略同じに形成される。 According to an embodiment of the present invention, the open / close width of the open / close valve of the carburetor is formed to be substantially the same as the radial width of the first intake passage.
　本発明の内燃機関の吸気装置によれば、内燃機関の低負荷時では、開度の小さい開閉弁からの吸入空気が気化器の流路壁に沿って第２吸気通路に流れやすくなり、燃焼室内にタンブル流を発生しやすくすることができる。また、内燃機関の高負荷時においては気化器の開閉弁の開度が大きくなり、大部分の吸入空気が第１吸気通路を流れるため、第２吸気通路を流れる流量を少なくでき、第１吸気通路と第２吸気通路を流れる吸入空気が吸気通路の下流で衝突することを抑制できる。
　さらに、気化器が、インレットパイプ中の第１吸気通路と第２吸気通路の分離点より上流に配置されるため、分離流路を備えた専用の気化器を設ける必要がなく、既存の気化器を流用することができる。 According to the intake device for an internal combustion engine of the present invention, when the internal combustion engine is under a low load, intake air from the opening / closing valve having a small opening angle easily flows into the second intake passage along the flow passage wall of the carburetor. A tumble flow can be easily generated in the room. Further, when the internal combustion engine is at a high load, the opening degree of the carburetor on / off valve increases, and most of the intake air flows through the first intake passage, so that the flow rate flowing through the second intake passage can be reduced, and the first intake air is reduced. It is possible to suppress the intake air flowing through the passage and the second intake passage from colliding downstream of the intake passage.
Furthermore, since the carburetor is disposed upstream of the separation point of the first intake passage and the second intake passage in the inlet pipe, there is no need to provide a dedicated carburetor having a separation flow path, and an existing carburetor is provided. Can be diverted.
　本発明の上記実施形態では、仕切板部の上流側端部が、インレットパイプと気化器の接続部から下流側に離間することによって、内燃機関の低負荷時に所望のタンブル比を得ることできるとともに、内燃機関の高負荷時には、第１吸気通路に流入する吸入空気の流量を確保することができる。 In the above embodiment of the present invention, the upstream end portion of the partition plate portion is spaced downstream from the connection portion between the inlet pipe and the carburetor, thereby obtaining a desired tumble ratio at a low load of the internal combustion engine. When the internal combustion engine is at a high load, the flow rate of the intake air flowing into the first intake passage can be ensured.
　本発明の上記実施形態では、気化器の開閉弁の下流側で、吸気の流れ方向で第２吸気通路へ向かって、吸気の流れの中心から該中心を離れる方向に傾斜する下がりスロープ部が形成されることにより、内燃機関の低負荷時において第２吸気通路に吸入空気を導きやすく、燃焼室内にタンブル流を発生しやすくすることができる。 In the above embodiment of the present invention, on the downstream side of the open / close valve of the carburetor, a downward slope portion is formed that inclines in the direction away from the center of the intake air flow toward the second intake passage in the intake air flow direction. Thus, intake air can be easily guided to the second intake passage when the internal combustion engine is under a low load, and a tumble flow can be easily generated in the combustion chamber.
　本発明の上記実施形態では、仕切板部が、シリンダヘッドにおいてシリンダブロック側に向けて屈曲して一体に形成された下流側端部を有し、第２吸気通路が、シリンダヘッドの燃焼室天井面を指向するように形成された終端を有することによって、第２吸気通路を流れる吸入空気を吸気弁の傘部の上方を通過させたうえで、シリンダボア内に流入させことができるため、燃焼室内においてタンブル流が発生しやすくすることができる。 In the above embodiment of the present invention, the partition plate portion has a downstream end portion integrally formed by bending toward the cylinder block side in the cylinder head, and the second intake passage is formed in the ceiling of the combustion chamber of the cylinder head. By having the end formed so as to face the surface, the intake air flowing through the second intake passage can pass through the upper portion of the umbrella portion of the intake valve and then flow into the cylinder bore. The tumble flow can be easily generated.
　本発明の上記実施形態では、インレットパイプと吸気ポートのインシュレータを介しての接続部において、インレットパイプ側仕切板部の下流側に接続するインシュレータ側仕切板部が薄く、インシュレータ側仕切板部の下流側に接続する吸気ポート側仕切板部が薄く、吸気空気の流れに従って接合部における各仕切板部の厚みが減じる段差形状に形成されるため、吸気通路を流れる吸入空気の流れに干渉することを抑制できる。また、組み付け誤差が生じる場合であっても、段差が形成されていることにより、組み付け誤差を吸収することができる。 In the above embodiment of the present invention, in the connecting portion of the inlet pipe and the intake port through the insulator, the insulator-side partition plate portion connected to the downstream side of the inlet pipe-side partition plate portion is thin, and the downstream of the insulator-side partition plate portion. Since the intake port side partition plate connected to the side is thin and is formed in a stepped shape in which the thickness of each partition plate at the joint decreases according to the flow of intake air, it interferes with the flow of intake air flowing through the intake passage. Can be suppressed. Further, even when an assembly error occurs, the assembly error can be absorbed by forming the step.
　本発明の上記実施形態においては、仕切板部の上流側端部に、下流側に凹む切り欠きが形成されることで、吸気通路に流入する吸入空気が仕切板部に当たる面積が徐々に増大するようにして、圧力と速度の変化を緩やかにし、流量損失を少なくすることができる。 In the above embodiment of the present invention, a notch recessed downstream is formed at the upstream end of the partition plate portion, so that the area where the intake air flowing into the intake passage hits the partition plate gradually increases. In this way, changes in pressure and speed can be moderated and flow loss can be reduced.
　本発明の上記実施形態によれば、仕切板部の上流側端部の両側端部が、気化器の開閉弁の開弁方向に向かって屈曲される。内燃機関の低負荷時に吸気通路内に流入する吸入空気は、吸気通路の下方から両側端の上方へ流れて扇状に流入する特性があるため、気化器の開閉弁の開弁方向に向かって屈曲する仕切板部の両側端部を設けることで、扇状に流入する吸入空気を受け止め、第２空気通路に導きやすくすることができる。
　また、併せ仕切板部の上流側端部に下流側に凹む切り欠きが形成された場合は、切り欠き凹みの中央部を気化器の開閉弁の全開時の吸入空気の流れが支障なく流れる。 According to the embodiment of the present invention, both end portions of the upstream end portion of the partition plate portion are bent toward the valve opening direction of the on-off valve of the carburetor. The intake air that flows into the intake passage when the internal combustion engine is under a low load flows from the lower side of the intake passage to the upper side of both sides and flows in a fan shape, so it bends toward the opening direction of the open / close valve of the carburetor By providing both side end portions of the partition plate portion to be received, it is possible to receive intake air flowing in a fan shape and easily guide it to the second air passage.
In addition, when a notch that is recessed downstream is formed at the upstream end of the partition plate portion, the flow of the intake air when the carburetor on-off valve is fully opened flows through the center of the notch recess without any problem.
　本発明の上記実施形態では、インレットパイプの吸気通路の径方向の幅が、第１吸気通路の径方向の幅と第２吸気通路の径方向の幅を含み、インレットパイプの吸気通路の径方向の幅が、気化器の開閉弁の開閉幅より大きいことにより、内燃機関の低負荷時では、開度の小さい開閉弁からの吸入空気が気化器の流路壁に沿って第２吸気通路に流れやすくなり、燃焼室内にタンブル流を発生しやすくすることができる。また、内燃機関の高負荷時においては気化器の開閉弁の開度が大きくなり、大部分の吸入空気が第１吸気通路を流れるため、第２吸気通路を流れる流量を少なくでき、第１吸気通路と第２吸気通路を流れる吸入空気が吸気通路の下流で衝突することを抑制できる。 In the above embodiment of the present invention, the radial width of the intake passage of the inlet pipe includes the radial width of the first intake passage and the radial width of the second intake passage, and the radial direction of the intake passage of the inlet pipe. Is larger than the opening / closing width of the on / off valve of the carburetor, so that when the internal combustion engine is under a low load, intake air from the on / off valve having a small opening degree flows into the second intake passage along the channel wall of the carburetor. It becomes easy to flow, and it can make it easy to generate a tumble flow in the combustion chamber. Further, when the internal combustion engine is at a high load, the opening degree of the carburetor on / off valve increases, and most of the intake air flows through the first intake passage, so that the flow rate flowing through the second intake passage can be reduced, and the first intake air is reduced. It is possible to suppress the intake air flowing through the passage and the second intake passage from colliding downstream of the intake passage.
　本発明の上記実施形態では、気化器の開閉弁の開閉幅が、第１吸気通路の径方向の幅と略同じに形成されることで、内燃機関の高負荷時に、吸気通路の流入する空気を第１吸気通路に流入しやすくでき、内燃機関の高負荷時において第１吸気通路を流れる吸入空気量を確保しやすくできる。 In the above embodiment of the present invention, the opening / closing width of the opening / closing valve of the carburetor is formed to be substantially the same as the radial width of the first intake passage, so that the air flowing into the intake passage at the time of high load of the internal combustion engine Can be easily flown into the first intake passage, and the amount of intake air flowing through the first intake passage can be easily secured when the internal combustion engine is at a high load.
本発明の実施形態に係る内燃機関の吸気装置を含むパワーユニットを搭載したスクータ型自動二輪車の右側面である。1 is a right side view of a scooter type motorcycle equipped with a power unit including an intake device for an internal combustion engine according to an embodiment of the present invention. 車体カバーを外した自動二輪車の後部右側面である。It is the rear right side surface of the motorcycle with the body cover removed. 図２に示すと同じ配向によるパワーユニットの前部、すなわち内燃機関の部分の側面断面図である。FIG. 3 is a side cross-sectional view of a front portion of a power unit having the same orientation as shown in FIG. 2, that is, a portion of an internal combustion engine. 図３の要部拡大図である。It is a principal part enlarged view of FIG. （ａ）部は、図４のインレットパイプのみを取り出し示すインレットパイプの変形例１の断面図であり、同図（ｂ）部は、（ａ）部中ｂ－ｂ矢視図である。Part (a) is a cross-sectional view of Modification 1 of the inlet pipe showing only the inlet pipe of FIG. 4, and part (b) is a view taken along the line bb in part (a). 図５の（ａ）部と同様に、図４のインレットパイプのみを取り出し示すインレットパイプの変形例２の断面図である。It is sectional drawing of the modification 2 of the inlet pipe which takes out only the inlet pipe of FIG. 4 like the (a) part of FIG.
　図面に基づき、本発明の一実施形態に係る内燃機関の吸気装置につき説明する。
　なお、本明細書の説明および請求の範囲における前後左右上下等の向きは、本実施形態に係る吸気装置を備えた内燃機関を搭載した車両に関しての向きに従うものとする。本実施形態において車両は小型車両であり、例えばスクータ型自動二輪車である。
　また、図中矢印ＦＲは車両前方を、ＬＨは車両左方を、ＲＨは車両右方を、ＵＰは車両上方を、それぞれ示す。 An intake device for an internal combustion engine according to an embodiment of the present invention will be described based on the drawings.
Note that the directions such as front, rear, left, right, up, down, etc. in the description and claims of the present specification are the same as those of a vehicle equipped with an internal combustion engine equipped with an intake device according to this embodiment. In the present embodiment, the vehicle is a small vehicle, for example, a scooter type motorcycle.
In the figure, an arrow FR indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle.
　図１に、本実施形態の内燃機関の吸気装置を備えるパワーユニットを搭載したスクータ型自動二輪車（以下、単に「自動二輪車」という。）１の右側面を示す。
　自動二輪車１は、車体前部１Ａと車体後部１Ｂとが、低いフロア部１Ｃを介して連結されており、車体の骨格をなす車体フレーム２は、概ねダウンチューブ21とメインパイプ22（図２参照）とからなる。
　すなわち、車体前部１Ａのヘッドパイプ20からダウンチューブ21が下方へ延出し、ダウンチューブ21は下端で水平に屈曲してフロア部１Ｃの下方を後方へ延び、図２に示されるようにその後端において車幅方向に配設された連結フレーム23を介して、左右一対のメインパイプ22が連結され、メインパイプ22は連結フレーム23から斜め後方に立ち上がって、途中、傾斜をゆるめるように屈曲して後方に延びている。 FIG. 1 shows a right side surface of a scooter type motorcycle (hereinafter simply referred to as “motorcycle”) 1 equipped with a power unit including an intake device for an internal combustion engine of the present embodiment.
In the motorcycle 1, a vehicle body front portion 1A and a vehicle body rear portion 1B are connected via a low floor portion 1C, and a vehicle body frame 2 forming a skeleton of the vehicle body is generally composed of a down tube 21 and a main pipe 22 (see FIG. 2). ).
That is, the down tube 21 extends downward from the head pipe 20 of the vehicle body front portion 1A, and the down tube 21 is bent horizontally at the lower end and extends rearward below the floor portion 1C, as shown in FIG. A pair of left and right main pipes 22 are connected via a connecting frame 23 arranged in the vehicle width direction in FIG. 2, and the main pipe 22 rises obliquely rearward from the connecting frame 23 and bends so that the inclination is loosened in the middle. It extends backward.
　メインパイプ22により乗員シート11等が支持され、その下方は車体カバー12で覆われている。
　一方、車体前部１Ａにおいては、ヘッドパイプ20に軸支されて上方にハンドル13が設けられ、下方にフロントフォーク14が延びてその下端に前輪15が軸支されている。 The occupant seat 11 and the like are supported by the main pipe 22, and the lower part thereof is covered with the vehicle body cover 12.
On the other hand, in the front part 1A of the vehicle body, a handle 13 is provided above and supported by the head pipe 20, a front fork 14 extends downward, and a front wheel 15 is supported at the lower end thereof.
　図２に、車体カバー12を外した自動二輪車１の後部右側面を示すように、メインパイプ22の傾斜部の下端付近にブラケット24が突設され、ブラケット24にリンク部材25を介してパワーユニット３が揺動可能に連結支持されている。
　パワーユニット３は、その前部が単気筒４ストロークサイクルの空冷式内燃機関（以下、単に「内燃機関」という。）30であり、クランクケース部50ａを構成するパワーユニットケース50の前部に、クランク軸51を車幅方向に配して回転自在に軸支し、シリンダ軸Ｘを略水平に近い状態にまで大きく前傾した姿勢にあって、パワーユニットケース50の下端から前方に突出したハンガアーム52の端部が、メインパイプ22のブラケット24に取付けられたリンク部材25を介して連結されている。 As shown in FIG. 2, the rear right side surface of the motorcycle 1 with the vehicle body cover 12 removed shows a bracket 24 projecting near the lower end of the inclined portion of the main pipe 22, and the power unit 3 is connected to the bracket 24 via the link member 25. Are supported in a swingable manner.
The power unit 3 is a single-cylinder four-stroke cycle air-cooled internal combustion engine (hereinafter simply referred to as “internal combustion engine”) 30, and the power unit 3 includes a crankshaft at the front of the power unit case 50 constituting the crankcase 50 a. An end of a hanger arm 52 projecting forward from the lower end of the power unit case 50 in a posture in which 51 is arranged in the vehicle width direction and rotatably supported, and the cylinder axis X is tilted largely forward to a substantially horizontal state. The parts are connected via a link member 25 attached to the bracket 24 of the main pipe 22.
　パワーユニット３は、クランクケース部50ａを構成するパワーユニットケース50の前部に略水平に大きく前傾する内燃機関30を備え、該内燃機関30を構成するシリンダブロック31、シリンダヘッド32、シリンダヘッドカバー33が順次積み上げられるように締結されている。クランクケース部50ａから左側後方にかけてベルト式無段変速機等を備えた動力伝動ケース部55が一体に延在し、その後部にパワーユニット３の出力軸である後車軸56が設けられ、後輪16が取り付けられている。
　なお、パワーユニット３の後部の動力伝動ケース部55と、メインパイプ22の後部との間には図示しないリヤクッションが介装されている。 The power unit 3 includes an internal combustion engine 30 that is largely inclined forward substantially horizontally at a front portion of the power unit case 50 that constitutes the crankcase portion 50a, and a cylinder block 31, a cylinder head 32, and a cylinder head cover 33 that constitute the internal combustion engine 30 are provided. It is concluded so that it may be piled up sequentially. A power transmission case portion 55 having a belt type continuously variable transmission or the like extends integrally from the crankcase portion 50a to the rear left side, and a rear axle 56 which is an output shaft of the power unit 3 is provided at the rear portion thereof. Is attached.
A rear cushion (not shown) is interposed between the power transmission case 55 at the rear of the power unit 3 and the rear of the main pipe 22.
　図２に示されるように、パワーユニット３の上部では、内燃機関30の大きく前傾したシリンダヘッド32の上部からインレットパイプ６が延出して後方に湾曲し、インレットパイプ６に接続された気化器７がシリンダブロック31の上方に位置し、気化器７にコネクティングチューブ37を介して図示しないエアクリーナ装置が動力伝動ケース部55の上方に配設されている。
　一方、シリンダヘッド32の下部から下方に延出した排気管38は、後方へ屈曲し右側に偏って後方に延びて後輪16の右側のマフラ39に接続される。 As shown in FIG. 2, in the upper part of the power unit 3, the inlet pipe 6 extends from the upper part of the cylinder head 32 inclined largely forward of the internal combustion engine 30, curves backward, and is connected to the inlet pipe 6. Is located above the cylinder block 31, and an air cleaner device (not shown) is disposed above the power transmission case 55 in the carburetor 7 via a connecting tube 37.
On the other hand, the exhaust pipe 38 extending downward from the lower part of the cylinder head 32 is bent rearward, is biased to the right and extends rearward, and is connected to the muffler 39 on the right side of the rear wheel 16.
　図３は、パワーユニット３の前部、すなわち内燃機関30の部分の、図２に示すと同じ配向による側面断面図である。内燃機関30は、シリンダブロック31のシリンダボア31ａ内を往復動するピストン34を有し、該ピストン34とクランク軸51のクランクピン51ａとをコネクティングロッド35が連結している。
　シリンダブロック31のシリンダボア31ａ内を摺動自在に嵌合されるピストン34の頂面34ａと、頂面34ａが対向するシリンダヘッド32の燃焼室天井面32ａとの間には燃焼室36が構成される。 3 is a side sectional view of the front portion of the power unit 3, that is, the portion of the internal combustion engine 30, with the same orientation as shown in FIG. The internal combustion engine 30 has a piston 34 that reciprocates in a cylinder bore 31 a of a cylinder block 31, and a connecting rod 35 connects the piston 34 and a crank pin 51 a of a crankshaft 51.
A combustion chamber 36 is formed between the top surface 34a of the piston 34 slidably fitted in the cylinder bore 31a of the cylinder block 31 and the combustion chamber ceiling surface 32a of the cylinder head 32 opposed to the top surface 34a. The
　本実施形態において、内燃機関30は、ＳＯＨＣ型式の２バルブシステムを採用しており、シリンダヘッド32に動弁機構９が設けられている。動弁機構９を覆うように、シリンダヘッド32にはシリンダヘッドカバー33が重ねられて被せられる。
　シリンダヘッドカバー33内の動弁機構９に動力伝達を行うため、図示しない無端状のカムチェーンが、クランクケース50ａ、シリンダブロック31、シリンダヘッド32のクランク軸51方向の一方側に設けられた図示しないカムチェーン室を通って、カム軸91とクランク軸51との間に架設され、カム軸91はクランク軸51に同期して１／２の回転速度で回転する。
　なお、シリンダヘッド32において前記カムチェーン室と反対側（クランク軸51方向の他方側）から燃焼室36内に向かって図示しない点火プラグが嵌挿されている。 In the present embodiment, the internal combustion engine 30 employs a SOHC type two-valve system, and the valve mechanism 9 is provided in the cylinder head 32. The cylinder head 32 is covered with a cylinder head cover 33 so as to cover the valve mechanism 9.
In order to transmit power to the valve operating mechanism 9 in the cylinder head cover 33, an endless cam chain (not shown) is provided on one side of the crankcase 50a, the cylinder block 31, and the cylinder head 32 in the direction of the crankshaft 51 (not shown). The camshaft chamber is installed between the camshaft 91 and the crankshaft 51 through the cam chain chamber, and the camshaft 91 rotates at a half rotational speed in synchronization with the crankshaft 51.
An ignition plug (not shown) is inserted into the combustion chamber 36 from the opposite side of the cam chain chamber (the other side in the direction of the crankshaft 51) in the cylinder head 32.
　図３に示すように、シリンダ軸線Ｘを略水平に近く大きく前傾したシリンダヘッド32においては、燃焼室天井面32ａに開口した吸気弁口40と排気弁口41からは、各々吸気ポート42と排気ポート43が互いに上下に離れる方向に湾曲しながら延出して形成される。
　吸気ポート42の上流端は、シリンダヘッド32の上方に向けてインレットパイプ６と接続して、連続した吸気通路80が構成され、インレットパイプ６の上流側に、気化器７が接続される。
　排気ポート43の下流端は、シリンダヘッド32の下方に向けて排気管38に連結される。 As shown in FIG. 3, in the cylinder head 32 inclined largely forward substantially near the cylinder axis X substantially horizontally, the intake port 42 and the exhaust valve port 41 opened in the combustion chamber ceiling surface 32 a The exhaust ports 43 are formed so as to extend while being curved away from each other in the vertical direction.
The upstream end of the intake port 42 is connected to the inlet pipe 6 toward the upper side of the cylinder head 32 to form a continuous intake passage 80, and the carburetor 7 is connected to the upstream side of the inlet pipe 6.
The downstream end of the exhaust port 43 is connected to the exhaust pipe 38 toward the lower side of the cylinder head 32.
　シリンダヘッド32における吸気ポート42の湾曲外壁部に一体に円筒状の弁ガイド44が嵌着され、弁ガイド44に摺動可能に支持された吸気弁46が、吸気ポート42の燃焼室36に臨む吸気弁口40を開閉する。
　また、シリンダヘッド32における排気ポート43の湾曲外壁部に一体に嵌着された弁ガイド45に摺動可能に支持された排気弁47が、排気ポート43の燃焼室36に臨む排気弁口41を開閉する。 A cylindrical valve guide 44 is integrally fitted to the curved outer wall portion of the intake port 42 in the cylinder head 32, and the intake valve 46 slidably supported by the valve guide 44 faces the combustion chamber 36 of the intake port 42. Open and close the intake valve port 40.
Further, an exhaust valve 47 slidably supported by a valve guide 45 fitted integrally with the curved outer wall portion of the exhaust port 43 in the cylinder head 32 has an exhaust valve port 41 facing the combustion chamber 36 of the exhaust port 43. Open and close.
　吸気弁46および排気弁47はその傘部46ａ、47ａが、いずれも燃焼室36に臨む吸気弁口40、排気弁口41を閉じるように、弁ばね48により上方に付勢されているが、カム軸91の吸気カム92、排気カム93に当接揺動する吸気ロッカアーム94、排気ロッカアーム95によって、吸気弁46、排気弁47のステムエンド46ｂ、47ｂが押し下げられて、所定のタイミングで吸気弁46、排気弁47が開弁し、吸気ポート42と燃焼室36、また、排気ポート43と燃焼室36が連通し、所定のタイミングの吸気、排気がなされる。 The intake valve 46 and the exhaust valve 47 are urged upward by the valve spring 48 so that the umbrella portions 46a and 47a both close the intake valve port 40 and the exhaust valve port 41 facing the combustion chamber 36. The intake valve 92 and the exhaust rocker arm 95 that abuts and swings against the intake cam 92 and the exhaust cam 93 of the camshaft 91 push down the stem ends 46b and 47b of the intake valve 46 and the exhaust valve 47, and the intake valve at a predetermined timing. 46 and the exhaust valve 47 are opened, and the intake port 42 and the combustion chamber 36 communicate with each other, and the exhaust port 43 and the combustion chamber 36 communicate with each other to perform intake and exhaust at a predetermined timing.
　以上のような本実施形態に係る内燃機関30において、燃焼室36でのより好ましい燃焼を得るために燃焼室36において燃料・空気混合気のタンブル流、すなわち縦回転を与えるための前記吸気通路80が形成されている。
　すなわち、吸気通路80は、インレットパイプ６から吸気ポート42へと続く仕切板部85によって、第１吸気通路80Ａと第２吸気通路80Ｂとに仕切られている。第２吸気通路80Ｂは、気化器７の開閉弁71の閉弁時の下端71ａに近い下側の下側通路でありタンブル流路となる。また、第１吸気通路80Ａは、第２吸気通路80Ｂを除く上側の上側通路であり主流路となる第１吸気通路80Ａとに仕切られている。 In the internal combustion engine 30 according to the present embodiment as described above, in order to obtain more preferable combustion in the combustion chamber 36, the intake passage 80 for providing a tumble flow of the fuel / air mixture in the combustion chamber 36, that is, longitudinal rotation. Is formed.
That is, the intake passage 80 is partitioned into a first intake passage 80A and a second intake passage 80B by a partition plate portion 85 that extends from the inlet pipe 6 to the intake port 42. The second intake passage 80B is a lower lower passage close to the lower end 71a when the on-off valve 71 of the carburetor 7 is closed, and serves as a tumble passage. The first intake passage 80A is an upper upper passage excluding the second intake passage 80B, and is partitioned into a first intake passage 80A serving as a main flow passage.
　本実施形態において、気化器７の流路70は、上流側がコネクティングチューブ37に接続し、図３の要部拡大図である図４に示されるように、下流端70ａがインシュレータ75を介してインレットパイプ６の上流側端部６ａ、すなわち吸気通路80の上流側端部80ａに接続されており、その途中にベンチュリー部72のベンチュリーピストンで形成される開閉弁71が流路70を横切って上下に変位可能に設けられる。気化器７は、開閉弁71の上流側にスロットルバルブ73が設けられて、負圧作動型気化器を構成しているが、それ自体は広く公知のものなので説明は省略する。
　開閉弁71の開放の初期位置（閉鎖の終期位置）では、開閉弁71の先端である下端71ａは、仕切板部85により第１吸気通路80Ａに対し仕切られた第２吸気通路80Ｂの上流端に流れ方向で対応する位置にある。そして、開閉弁71の先端を構成する下端71ａは、開閉弁71の閉鎖状態で、タンブル流路である第２吸気通路80Ｂに流れ方向で対応する位置にある、流路内壁部分としての底部70ｂに押し付けられる。 In the present embodiment, the flow path 70 of the vaporizer 7 is connected to the connecting tube 37 on the upstream side, and the downstream end 70a is connected to the inlet 75 via the insulator 75 as shown in FIG. Connected to the upstream end 6 a of the pipe 6, that is, to the upstream end 80 a of the intake passage 80, an on-off valve 71 formed by a venturi piston of the venturi 72 is vertically moved across the flow path 70. Displaceable. The carburetor 7 is provided with a throttle valve 73 on the upstream side of the on-off valve 71 to constitute a negative pressure operation type carburetor.
At the initial opening position of the on-off valve 71 (the closing end position), the lower end 71a that is the tip of the on-off valve 71 is the upstream end of the second intake passage 80B that is partitioned from the first intake passage 80A by the partition plate 85. In the position corresponding to the flow direction. The lower end 71a constituting the tip of the on-off valve 71 is a bottom portion 70b as a channel inner wall portion at a position corresponding to the second intake passage 80B, which is a tumble channel, in the flow direction when the on-off valve 71 is closed. Pressed against.
　図４に示されるように、開閉弁71は、上記のように流路70の下側内壁である底部70ｂに押し付けられて流路70を閉じるが、開閉弁71が開かれるとベンチュリー部72から燃料が吸い出され吸入空気との混合気となって、気化器７の下流側の流路70からインレットパイプ６へ、すなわち吸気通路80へと送られる。
　内燃機関の低負荷時に吸気通路内に流入する吸入空気と燃料との混合気（以下、単に「吸入空気」という。）は、開度の小さい開閉弁71の下端71ａと流路70の底部70ｂとの間から底部70ｂに沿って扇状に流れ出て、吸気通路80に至る特性がある。 As shown in FIG. 4, the on-off valve 71 is pressed against the bottom 70 b that is the lower inner wall of the flow path 70 as described above to close the flow path 70, but when the on-off valve 71 is opened, the venturi section 72 The fuel is sucked out to be mixed with the intake air, and sent from the flow path 70 on the downstream side of the carburetor 7 to the inlet pipe 6, that is, to the intake passage 80.
A mixture of intake air and fuel (hereinafter simply referred to as “intake air”) flowing into the intake passage when the internal combustion engine is under low load is a lower end 71a of the opening / closing valve 71 having a small opening and a bottom portion 70b of the flow path 70. The air flows out in a fan shape along the bottom 70b from between the air and the intake passage 80.
　そこで、本実施形態では、図４に断面視で示すように、気化器７の開閉弁71の閉弁時の下端71ａと、仕切板部85の上流側端部85ａとが、開閉弁71の上下移動方向で略同じに高さに位置している。換言するならば、開閉弁71は、その閉弁時に流路70の底部70ｂに押し付けられるが、該底部70ｂは、開閉弁71の上下移動方向に関して、仕切板部85の上流側端部85ａと略対応する位置にある。
　また、気化器７はその流路70の下流端70ａが、インシュレータ75を介してインレットパイプ６内の吸気通路80の上流側端部80ａに接続されている。すなわち気化器７は、吸気通路80の第１吸気通路80Ａと第２吸気通路80Ｂとの分離点より上流側に配置されている。
　　したがって、第２吸気通路80Ｂの図４図示上の底部80Ｂaは、気化器７の下流側の流路70の図４図示上の底部70ｂより低い位置に配設され、第２吸気通路80Ｂの図４図示上の上流端側底部80Ｂbは、気化器７の流路70の図４図示上の底部70ｂの高さから徐々に下がる下がりスロープ部81をなしている。換言するならば、気化器７の流路70の底部70ｂから上流端側底部80Ｂbを経て第２吸気通路80Ｂの底部80Ｂaへ向かうにつれ、吸気通路80の内壁は、下がりスロープ部81において、吸気の流れの中心から該中心を離れる方向に形成されている。そして、下がりスロープ部81のうち、第２吸気通路80Ｂの上流端側底部80Ｂbにおける傾斜が最も大きい下がり傾斜となっている。 Therefore, in the present embodiment, as shown in a cross-sectional view in FIG. 4, the lower end 71 a when the on-off valve 71 of the carburetor 7 is closed and the upstream end 85 a of the partition plate portion 85 are connected to the on-off valve 71. It is located at almost the same height in the vertical movement direction. In other words, the opening / closing valve 71 is pressed against the bottom 70b of the flow path 70 when the valve is closed, and the bottom 70b is connected to the upstream end 85a of the partition plate 85 with respect to the vertical movement direction of the opening / closing valve 71. It is in a substantially corresponding position.
The vaporizer 7 has a downstream end 70 a of the flow path 70 connected to an upstream end 80 a of the intake passage 80 in the inlet pipe 6 via an insulator 75. That is, the carburetor 7 is disposed upstream of the separation point between the first intake passage 80A and the second intake passage 80B of the intake passage 80.
Accordingly, the bottom portion 80Ba of the second intake passage 80B shown in FIG. 4 is disposed at a position lower than the bottom portion 70b of the flow path 70 on the downstream side of the carburetor 7 shown in FIG. The upstream end bottom portion 80Bb shown in FIG. 4 forms a downward slope portion 81 that gradually falls from the height of the bottom portion 70b shown in FIG. In other words, the inner wall of the intake passage 80 is lowered in the downward slope portion 81 from the bottom portion 70b of the flow path 70 of the carburetor 7 to the bottom portion 80Ba of the second intake passage 80B through the upstream end side bottom portion 80Bb. It is formed in a direction away from the center of the flow. Of the descending slope portion 81, the slope at the upstream end bottom portion 80Bb of the second intake passage 80B is the largest descending slope.
　そのため、内燃機関30の低負荷時では、吸入空気が第２吸気通路80Ｂに流れやすくなり、燃焼室36内にタンブル流を発生しやすくすることができる。また、内燃機関30の高負荷時においては気化器７の開閉弁71の開度が大きくなり、大部分の吸入空気が第１吸気通路80Ａを流れるため、第２吸気通路80Ｂを流れる流量を少なくでき、第１吸気通路80Ａと第２吸気通路80Ｂを流れる吸入空気が吸気通路80の下流、すなわち吸気ポート42の下流側で衝突することを抑制できる。
　さらに、気化器７が第１吸気通路80Ａと第２吸気通路の分離点より上流に配置されるため、吸入空気の分離流路を備える専用の気化器を設ける必要がなく、既存の気化器を流用することができる。 Therefore, when the internal combustion engine 30 is at a low load, the intake air easily flows into the second intake passage 80B, and a tumble flow can be easily generated in the combustion chamber 36. Further, when the internal combustion engine 30 is at a high load, the opening / closing valve 71 of the carburetor 7 increases, and most of the intake air flows through the first intake passage 80A, so that the flow rate flowing through the second intake passage 80B is reduced. In addition, the intake air flowing through the first intake passage 80A and the second intake passage 80B can be prevented from colliding downstream of the intake passage 80, that is, downstream of the intake port 42.
Further, since the carburetor 7 is disposed upstream of the separation point between the first intake passage 80A and the second intake passage, there is no need to provide a dedicated carburetor having a separation flow path for intake air, and an existing carburetor can be used. Can be diverted.
　なお、下がりスロープ部81はインレットパイプ６、インシュレータ75の何れに設けてもよく、また気化器７に設けてもよい。
　本実施形態においては、気化器７にも、開閉弁71の下流側の流路70の図４図示上の底部70ｂに、下がりスロープ部74が形成されている。
　すなわち、気化器７の開閉弁71の下流側に、下がりスロープ部74、81が形成されたことにより、第２吸気通路80Ｂを下方に形成することができ、内燃機関30の低負荷時において第２吸気通路80Ｂに吸入空気を導きやすく、燃焼室36内にタンブル流を発生しやすくすることができる。 The descending slope portion 81 may be provided in either the inlet pipe 6 or the insulator 75, or may be provided in the vaporizer 7.
In the present embodiment, the vaporizer 7 is also formed with a falling slope portion 74 at the bottom portion 70b of the flow path 70 on the downstream side of the on-off valve 71 in FIG.
That is, since the slopes 74 and 81 are formed on the downstream side of the on-off valve 71 of the carburetor 7, the second intake passage 80B can be formed downward. 2. The intake air can be easily guided to the intake passage 80B, and a tumble flow can be easily generated in the combustion chamber.
　また、仕切板部85の上流側端部85ａは、インレットパイプ６と気化器７の接続部から下流側に離間しており、そのため、内燃機関30の低負荷時には第２吸気通路80Ｂへ路壁に沿って吸入空気が流れ所望のタンブル比を得ることできるとともに、内燃機関の高負荷時には、第１吸気通路80Ｂに流入する吸入空気の流量を確保することができる。 Further, the upstream end portion 85a of the partition plate portion 85 is spaced downstream from the connection portion between the inlet pipe 6 and the carburetor 7, so that when the internal combustion engine 30 is under a low load, the road wall extends to the second intake passage 80B. As a result, the desired amount of tumble ratio can be obtained and the flow rate of the intake air flowing into the first intake passage 80B can be ensured when the internal combustion engine is under a high load.
　また、図４に示されるように、仕切板部85の下流側端部85ｂは、シリンダヘッド32の吸気ポート42内に位置し、この下流側端部85ｂは、シリンダヘッド32においてシリンダブロック31側に向けて屈曲して一体に形成され、第２吸気通路80Ｂの終端80Ｂcは、シリンダヘッド32の燃焼室天井面32ａを指向するように形成されている。
　そのため、第２吸気通路80Ｂを流れる吸入空気を、図４中小矢印が示すように、吸気弁46の傘部46ａの上方を通過させたうえで、シリンダボア31ａ内に流入させことができるため、燃焼室36内においてタンブル流が発生しやすくすることができる As shown in FIG. 4, the downstream end 85b of the partition plate 85 is located in the intake port 42 of the cylinder head 32, and the downstream end 85b is located on the cylinder block 31 side in the cylinder head 32. The end 80Bc of the second intake passage 80B is formed so as to face the combustion chamber ceiling surface 32a of the cylinder head 32.
For this reason, the intake air flowing through the second intake passage 80B can flow into the cylinder bore 31a after passing over the umbrella portion 46a of the intake valve 46, as indicated by the small arrows in FIG. Tumble flow can be easily generated in the chamber 36.
　図４に示されるように、吸気ポート42とインレットパイプ６は、インシュレータ60を介して接続され、仕切板部85は、インレットパイプ側仕切板部85Ａと、吸気ポート側仕切板部85Ｂと、インシュレータ領域仕切板部85Ｃとを備えて構成される。
　そして、インレットパイプ側仕切板部85Ａの下流側端部85Ａbは、インシュレータ領域仕切板85Ｃの上流側端部85Ｃaより厚く形成され、インシュレータ領域仕切板部85Ｃの下流側端部85Ｃbは、吸気ポート側仕切板部85Ｂの上流側端部85Ｂaより厚く形成されている。 As shown in FIG. 4, the intake port 42 and the inlet pipe 6 are connected via an insulator 60, and the partition plate portion 85 includes an inlet pipe side partition plate portion 85A, an intake port side partition plate portion 85B, and an insulator. An area partition plate portion 85C is provided.
The downstream end 85Ab of the inlet pipe side partition plate 85A is formed thicker than the upstream end 85Ca of the insulator region partition plate 85C, and the downstream end 85Cb of the insulator region partition plate 85C is on the intake port side. It is formed thicker than the upstream end 85Ba of the partition plate 85B.
　そのため、インレットパイプ６と吸気ポート42のインシュレータ60を介しての接続部において、インレットパイプ側仕切板部85Ａの下流側に接続するインシュレータ領域仕切板部85Ｃが薄く、インシュレータ領域仕切板部85Ｃの下流側に接続する吸気ポート側仕切板部85Ｂが薄く、吸気空気の流れに従って接合部における各仕切板部85Ａ、85Ｃ、85Ｂの厚みが減じる段差形状に形成されたため、吸気通路80を流れる吸入空気の流れに干渉することを抑制できる。また、組み付け誤差が生じる場合であっても、段差が形成されていることにより、組み付け誤差を吸収することができる。 Therefore, in the connection portion of the inlet pipe 6 and the intake port 42 via the insulator 60, the insulator region partition plate portion 85C connected to the downstream side of the inlet pipe side partition plate portion 85A is thin, and the downstream of the insulator region partition plate portion 85C. Since the intake port side partition plate portion 85B connected to the side is thin and formed in a stepped shape in which the thickness of each partition plate portion 85A, 85C, 85B in the joint portion decreases according to the flow of intake air, the intake air flowing through the intake passage 80 Interference with the flow can be suppressed. Further, even when an assembly error occurs, the assembly error can be absorbed by forming the step.
　また、図４に示されるように、インレットパイプ６の吸気通路80の径方向の幅Ｗ１は、第１吸気通路80Ａの径方向の幅Ｗ２と前記第２吸気通路80Ｂの径方向の幅Ｗ３を含むが、インレットパイプ６の吸気通路80の径方向の幅Ｗ１は、前記気化器７の開閉弁71の開閉幅Ｗ４より大きく形成されている。
　そのため、内燃機関30の低負荷時では、開度の小さい開閉弁71からの吸入空気が気化器７の流路70の底部70ｂの壁に沿って第２吸気通路80Ｂに流れやすくなり、燃焼室36内にタンブル流を発生しやすくすることができる。
　また、内燃機関30の高負荷時においては気化器７の開閉弁71の開度が大きくなり、大部分の吸入空気が第１吸気通路80Ａを流れる。したがって、第２吸気通路80Ｂを流れる流量を少なくでき、第１吸気通路880Ａと第２吸気通路80Ｂを流れる吸入空気が吸気通路80の下流で衝突することを抑制できる。 As shown in FIG. 4, the radial width W1 of the intake passage 80 of the inlet pipe 6 is equal to the radial width W2 of the first intake passage 80A and the radial width W3 of the second intake passage 80B. However, the radial width W1 of the intake passage 80 of the inlet pipe 6 is formed larger than the open / close width W4 of the open / close valve 71 of the carburetor 7.
Therefore, when the internal combustion engine 30 is under a low load, the intake air from the opening / closing valve 71 having a small opening is likely to flow along the wall of the bottom 70b of the flow path 70 of the carburetor 7 into the second intake passage 80B. Tumble flow can be easily generated in 36.
Further, when the internal combustion engine 30 is at a high load, the opening degree of the on-off valve 71 of the carburetor 7 is increased, and most of the intake air flows through the first intake passage 80A. Therefore, the flow rate flowing through the second intake passage 80B can be reduced, and the intake air flowing through the first intake passage 880A and the second intake passage 80B can be prevented from colliding downstream of the intake passage 80.
　また、気化器７の開閉弁71の開閉幅Ｗ４は、第１吸気通路80Ａの径方向の幅Ｗ２と略同じに形成されているので、気化器７の開閉弁71の開閉幅と第１吸気通路80Ａの径方向の幅を略同じにすることによって、内燃機関30の高負荷時に、吸気通路80に流入する空気を第１吸気通路80Ａに流入しやすくでき、内燃機関30の高負荷時において第１吸気通路80Ａを流れる吸入空気量を確保しやすくなる。 Further, since the opening / closing width W4 of the opening / closing valve 71 of the carburetor 7 is formed substantially the same as the radial width W2 of the first intake passage 80A, the opening / closing width of the opening / closing valve 71 of the carburetor 7 and the first intake air. By making the radial width of the passage 80A substantially the same, the air flowing into the intake passage 80 can easily flow into the first intake passage 80A when the internal combustion engine 30 is heavily loaded. It becomes easy to secure the amount of intake air flowing through the first intake passage 80A.
　また、図５の（ａ）部は、図４のインレットパイプ６のみを取り出し示すインレットパイプ６の変形例１の断面図であり、同図（ｂ）部は、（ａ）部中ｂ－ｂ矢視図である。
　本変形例では、特に（ｂ）部に示されるように、仕切板部85の上流側端部85ａ、すなわちインレットパイプ側仕切板部85Ａの上流側端部85Ａaには、上述の実施形態のように端部が平面状ではなく、下流側に凹む切り欠き87が形成されている。切り欠き87の形状は、図示のＶ字状であってもよく、あるいはＵ字状であってもよい。
　そのようにすることによって、吸気通路80に流入する吸入空気が仕切板部85に当たる面積が徐々に増大するようにして、圧力と速度の変化を緩やかにし、流量損失を少なくすることができる。 5 (a) is a cross-sectional view of Modification 1 of the inlet pipe 6 showing only the inlet pipe 6 of FIG. 4, and FIG. 5 (b) is a cross-sectional view taken along line bb in FIG. 5 (a). It is an arrow view.
In this modified example, as shown in the part (b) in particular, the upstream end 85a of the partition plate 85, that is, the upstream end 85Aa of the inlet pipe side partition 85A is as described in the above embodiment. The end portion is not planar, and a notch 87 is formed to be recessed downstream. The shape of the notch 87 may be the V shape shown in the figure, or may be a U shape.
By doing so, it is possible to gradually increase the area where the intake air flowing into the intake passage 80 hits the partition plate portion 85, to moderate changes in pressure and speed, and to reduce flow loss.
　また、図６は、図５の（ａ）部と同様に、図４のインレットパイプ６のみを取り出し示すインレットパイプ６の変形例２の断面図であり、インレットパイプ６の上流側端部６ａ近傍のみを示す。
　本変形例では、仕切板部85の上流側端部85ａの両側端部88が上方に屈曲された、せり上がり89を有している。すなわち、せり上がり89は、気化器７の開閉弁71の開弁方向に向かっている。 6 is a sectional view of Modification 2 of the inlet pipe 6 in which only the inlet pipe 6 of FIG. 4 is taken out, similar to the part (a) of FIG. 5, and in the vicinity of the upstream end 6 a of the inlet pipe 6. Show only.
In this modification, both end portions 88 of the upstream end portion 85a of the partition plate portion 85 have a rising 89 that is bent upward. That is, the rising 89 is in the opening direction of the on-off valve 71 of the carburetor 7.
　図６は、上記変形例１の特徴も併せ備えて、仕切板部85の上流側端部85ａに下流側に凹む切り欠き87も備えたものを図示しているが、上述の実施形態のように仕切板部85の上流側端部85ａが直線状に形成され切り欠き87を備えないものであってもよい。
　内燃機関30の低負荷時に吸気通路80内に流入する吸入空気は、吸気通路80の下方から両側端の上方へ流れて扇状に流入する特性があるため、上方に屈曲しせり上がる仕切板部85の両側端部88を設けることで、扇状に流入する吸入空気を受け止め、第２空気通路80Ａに導きやすくすることができる。
　また、上記変形例１の特徴も併せ備えて、仕切板部85の上流側端部85ａに下流側に凹む切り欠き87が形成された場合は、切り欠き凹みの中央部を気化器７の開閉弁71の全開時の吸入空気の流れが支障なく流れるようにできる。 FIG. 6 also shows the feature of the first modified example, in which the upstream end 85a of the partition plate 85 is also provided with a notch 87 recessed downstream, as in the above-described embodiment. Further, the upstream end 85a of the partition plate 85 may be formed in a straight line and not provided with the notch 87.
The intake air flowing into the intake passage 80 when the internal combustion engine 30 is under a low load flows from the lower side of the intake passage 80 to the upper side of both sides and flows in a fan shape. By providing the both end portions 88, it is possible to receive the intake air flowing in a fan shape and easily guide it to the second air passage 80A.
In addition, when the notch 87 that is recessed downstream is formed in the upstream end 85a of the partition plate portion 85, the feature of the first modification is also provided, and the central portion of the notch recess is opened and closed. The flow of the intake air when the valve 71 is fully opened can flow without any trouble.
　以上、本発明の実施形態につき説明したが、本発明の態様が上記実施形態に限定されず、本発明の要旨の範囲で、多様な態様で実施されるものを含むことは勿論である。
　説明の便宜上、シリンダ軸線Ｘが略水平に近く前傾した内燃機関を有するパワーユニットにつき図示の左右配置のものについて説明したが、例えば車両、パワーユニット、内燃機関のタイプの異なるもの、シリンダ軸線の立ち上がったもの、左右配置の異なるものであっても、発明の要旨の範囲であれば本発明に含まれる。 Although the embodiments of the present invention have been described above, the aspects of the present invention are not limited to the above-described embodiments, and it is needless to say that the present invention includes those implemented in various aspects within the scope of the gist of the present invention.
For convenience of explanation, the power unit having the internal combustion engine in which the cylinder axis X is tilted substantially horizontally and forward has been described with respect to the left and right arrangements shown in the figure. For example, the vehicle, power unit, different types of the internal combustion engine, Even those having different left and right arrangements are included in the present invention within the scope of the gist of the invention.
　１…自動二輪車（スクータ型自動二輪車）、３…パワーユニット、６…インレットパイプ、６ａ…上流側端部、７…気化器、30…内燃機関（空冷式内燃機関）、31…シリンダブロック、31ａ…シリンダボア、32…シリンダヘッド、32ａ…燃焼室天井面、33…シリンダヘッドカバー、34…ピストン、34ａ…頂面、36…燃焼室、37…コネクティングチューブ、40…吸気弁口、41…排気弁口、42…吸気ポート、43…排気ポート、44…弁ガイド、46…吸気弁、46ａ…傘部、48…弁ばね、50…パワーユニットケース、50ａ…クランクケース部、51…クランク軸、60…インシュレータ、70…流路、70ａ…下流端、70ｂ…底部、71…開閉弁、71ａ…下端、72…ベンチュリー部、74…下がりスロープ部、75…インシュレータ、80…吸気通路、80Ａ…第１吸気通路、80Ｂ…第２吸気通路、80Ｂa…底部、80Ｂb…上流端側底部、80Ｂｃ…終端、80ａ…上流側端部、81…下がりスロープ部、85…仕切板部、85ａ…上流側端部、85ｂ…下流側端部、85Ａ…インレットパイプ側仕切板部、85Ａa…上流側端部、85Ａb…下流側端部、85Ｂ…吸気ポート側仕切板部、85Ｂa…上流側端部、85Ｃ…インシュレータ側仕切板部、85Ｃa…上流側端部、85Ｃb…下流側端部、87…切り欠き、88…側端部、89…せり上がり、Ｘ…シリンダ軸、Ｗ１…吸気通路80の径方向の幅、Ｗ２…第１吸気通路80Ａの径方向の幅、Ｗ３…第２吸気通路80Ｂの径方向の幅、Ｗ４…気化器７の開閉弁71の開閉幅 DESCRIPTION OF SYMBOLS 1 ... Motorcycle (scooter type motorcycle), 3 ... Power unit, 6 ... Inlet pipe, 6a ... Upstream end, 7 ... Vaporizer, 30 ... Internal combustion engine (air-cooled internal combustion engine), 31 ... Cylinder block, 31a ... Cylinder bore, 32 ... Cylinder head, 32a ... Combustion chamber ceiling surface, 33 ... Cylinder head cover, 34 ... Piston, 34a ... Top surface, 36 ... Combustion chamber, 37 ... Connecting tube, 40 ... Intake valve port, 41 ... Exhaust valve port, 42 ... Intake port, 43 ... Exhaust port, 44 ... Valve guide, 46 ... Intake valve, 46a ... Umbrella part, 48 ... Valve spring, 50 ... Power unit case, 50a ... Crank case part, 51 ... Crankshaft, 60 ... Insulator, 70 ... flow path, 70a ... downstream end, 70b ... bottom, 71 ... open / close valve, 71a ... lower end, 72 ... venturi section, 74 ... falling slope section, 75 ... insulator, 80 ... intake passage, 80A ... first intake passage, 80B ... 2nd intake passage , 80Ba ... Bottom, 80Bb ... Upstream end bottom, 80Bc ... Termination, 80a ... Upstream end, 81 ... Down slope, 85 ... Partition plate, 85a ... Upstream end, 85b ... Downstream end, 85A ... Inlet pipe side partition plate portion, 85Aa ... Upstream end portion, 85Ab ... Downstream end portion, 85B ... Intake port side partition plate portion, 85Ba ... Upstream side end portion, 85C ... Insulator side partition plate portion, 85Ca ... Upstream side End portion, 85Cb ... downstream end portion, 87 ... notch, 88 ... side end portion, 89 ... rising, X ... cylinder shaft, W1 ... radial width of intake passage 80, W2 ... first intake passage 80A Width in radial direction, W3: Width in radial direction of second intake passage 80B, W4: Width of opening / closing valve 71 of carburetor 7

Claims (9)

  1. 　シリンダブロック(31)のシリンダボア(31ａ)内を摺動自在に嵌合されるピストン(34)の頂面(34ａ)と同頂面(34ａ)が対向するシリンダヘッド(32)の燃焼室天井面(32ａ)との間に燃焼室(36)が構成され 、前記シリンダヘッド(32)には、前記燃焼室天井面(32ａ)に開口した吸気弁口(40)と排気弁口(41)から各々吸気ポート(42)と排気ポート(43)が互いに離れる方向に湾曲しながら延出して形成され、
    　前記吸気ポート(42)にインレットパイプ(６)が接続されて連続した吸気通路(80)が構成され、前記インレットパイプ(６)の上流側に気化器(７)が接続され、該気化器(７)は、その内部の流路(70)を横切って該流路(70)を開閉するように変位可能の開閉弁(71)を備え、
    　前記吸気通路(80)が、前記気化器(７)の開閉弁(71)の閉弁時にその先端(71ａ)が押し付けられる前記流路(70)の内壁部に吸気の流れ方向で対応する第２吸気通路(80Ｂ)と、同第２吸気通路(80Ｂ)を除く第１吸気通路(80Ａ)とを仕切る仕切板部(85)を有する内燃機関の吸気装置において、
    　前記気化器(７)は、前記吸気通路(80)の上流側端部(80ａ)に接続され、
    　前記気化器(７)の開閉弁(71)の閉弁時に、該開閉弁の先端(71ａ)が押し付けられる前記流路(70)の内壁部(70ｂ)と前記仕切板部(85)の上流側端部(85ａ)とが、前記開閉弁(71)の変位方向に関して対応する位置にあることを特徴とする内燃機関の吸気装置。     Combustion chamber ceiling surface of the cylinder head (32) facing the top surface (34a) of the piston (34) slidably fitted in the cylinder bore (31a) of the cylinder block (31) A combustion chamber (36) is formed between the intake valve port (40) and the exhaust valve port (41) open to the ceiling surface (32a) of the combustion chamber. Each of the intake port (42) and the exhaust port (43) is formed to extend while curving in a direction away from each other,
    An inlet pipe (6) is connected to the intake port (42) to form a continuous intake passage (80), and a carburetor (7) is connected to the upstream side of the inlet pipe (6). 7) includes an open / close valve (71) that is displaceable so as to open and close the flow path (70) across the internal flow path (70),
    The intake passage (80) corresponds to the inner wall portion of the flow path (70) in which the front end (71a) is pressed when the on-off valve (71) of the carburetor (7) is closed in the direction of intake air flow. In an intake device for an internal combustion engine having a partition plate portion (85) that partitions the two intake passages (80B) and the first intake passages (80A) excluding the second intake passages (80B),
    The carburetor (7) is connected to an upstream end (80a) of the intake passage (80),
    When the on-off valve (71) of the carburetor (7) is closed, the inner wall (70b) of the flow path (70) against which the tip (71a) of the on-off valve is pressed and the upstream of the partition plate (85) An intake device for an internal combustion engine, wherein the side end (85a) is in a position corresponding to the displacement direction of the on-off valve (71).
  2. 　前記仕切板部(85)の上流側端部(85ａ)は、前記インレットパイプ(６)と前記気化器(７)の接続部から下流側に離間していることを特徴とする請求項１に記載の内燃機関の吸気装置。 The upstream end (85a) of the partition plate (85) is spaced downstream from the connection between the inlet pipe (6) and the vaporizer (7). An intake device for an internal combustion engine as described.
  3. 　前記気化器(７)の前記開閉弁(71)の下流側で、前記吸気の流れ方向で前記第２吸気通路(80Ｂ)へ向かって、吸気の流れの中心から該中心を離れる方向に傾斜する下がりスロープ部(74、81)が形成されたことを特徴とする請求項１または請求項２に記載の内燃機関の吸気装置。 On the downstream side of the on-off valve (71) of the carburetor (7), it inclines in a direction away from the center of the flow of intake air toward the second intake passage (80B) in the flow direction of the intake air. The intake device for an internal combustion engine according to claim 1 or 2, wherein a descending slope portion (74, 81) is formed.
  4. 　前記仕切板部(85)は、前記シリンダヘッド(32)において前記シリンダブロック(31)側に向けて屈曲して一体に形成された下流側端部(85ｂ)を有し、
    　前記第２吸気通路(80Ｂ)は、前記シリンダヘッド(32)の前記燃焼室天井面(32ａ)を指向するように形成された終端(80Ｂc)を有することを特徴とする請求項１ないし請求項３のいずれか一項に記載の内燃機関の吸気装置。     The partition plate portion (85) has a downstream end portion (85b) formed integrally with the cylinder head (32) by bending toward the cylinder block (31) side,
    The second intake passage (80B) has a terminal end (80Bc) formed to face the combustion chamber ceiling surface (32a) of the cylinder head (32). The intake device for an internal combustion engine according to any one of claims 3 to 4.
  5. 　前記吸気ポート(42)と前記インレットパイプ(６)は、インシュレータ(60)を介して接続され、
    　前記仕切板部(85)は、インレットパイプ側仕切板部(85Ａ)と、吸気ポート側仕切板部(85Ｂ)と、インシュレータ領域仕切板部(85Ｃ)とを備え、
    　前記インレットパイプ側仕切板部(85Ａ)の下流側端部(85Ａb)は、前記インシュレータ領域仕切板(85Ｃ)の上流側端部(85Ｃa)より厚く形成され、
    　前記インシュレータ領域仕切板部(85Ｃ)の下流側端部(85Ｃb)は、前記吸気ポート側仕切板部(85Ｂ)の上流側端部(85Ｂa)より厚く形成されたことを特徴とする請求項１ないし請求項４のいずれか一項に記載の内燃機関の吸気装置。     The intake port (42) and the inlet pipe (6) are connected via an insulator (60),
    The partition plate portion (85) includes an inlet pipe side partition plate portion (85A), an intake port side partition plate portion (85B), and an insulator region partition plate portion (85C).
    The downstream end (85Ab) of the inlet pipe side partition (85A) is formed thicker than the upstream end (85Ca) of the insulator region partition (85C),
    The downstream end (85Cb) of the insulator region partition plate (85C) is formed to be thicker than the upstream end (85Ba) of the intake port side partition plate (85B). An intake device for an internal combustion engine according to any one of claims 4 to 4.
  6. 　前記仕切板部(85)の前記上流側端部(85a)に、下流側に凹む切り欠き(87)が形成されたことを特徴とする請求項１ないし請求項５のいずれか一項に記載の内燃機関の吸気装置。 The notch (87) recessed in the downstream is formed in the upstream end (85a) of the partition plate (85), according to any one of claims 1 to 5. Intake device for internal combustion engine.
  7. 　前記仕切板部(85)の前記上流側端部(85a)の両側端部(88)が、前記気化器(７)の開閉弁(71)の開弁方向に向かって屈曲されたことを特徴とする請求項１ないし請求項６のいずれか一項に記載の内燃機関の吸気装置。 Both end portions (88) of the upstream end portion (85a) of the partition plate portion (85) are bent toward the valve opening direction of the on-off valve (71) of the vaporizer (7). An intake device for an internal combustion engine according to any one of claims 1 to 6.
  8. 　シリンダブロック(31)のシリンダボア(31ａ)内を摺動自在に嵌合されるピストン(34)の頂面(34ａ)と同頂面(34ａ)が対向するシリンダヘッド(32)の燃焼室天井面(32ａ)との間に燃焼室(36)が構成され 、前記シリンダヘッド(32)には、前記燃焼室天井面(32ａ)に開口した吸気弁口(40)と排気弁口(41)から各々吸気ポート(42)と排気ポート(43)が互いに離れる方向に湾曲しながら延出して形成され、
    　前記吸気ポート(42)にインレットパイプ(６)が接続されて連続した吸気通路(80)が構成され、前記インレットパイプ(６)の上流側に、気化器(７)が接続され、該気化器(７)は、その内部の流路(70)を横切って該流路(70)を開閉するように変位可能の開閉弁(71)を備え、
    　前記吸気通路(80)が、前記気化器(７)の開閉弁(71)の閉弁時にその先端(71ａ)が押し付けられる前記流路(70)の内壁部に吸気の流れ方向で対応する第２吸気通路(80Ｂ)と、同第２吸気通路(80Ｂ)を除く第１吸気通路(80Ａ)とを仕切る仕切板部(85)を有する内燃機関の吸気装置において、
    　前記インレットパイプ(６)の前記吸気通路(80)の径方向の幅(Ｗ１)は、前記第１吸気通路(80Ａ)の径方向の幅(Ｗ２)と前記第２吸気通路(80Ｂ)の径方向の幅(Ｗ３)を含み、
    　前記インレットパイプ(６)の前記吸気通路(80)の径方向の幅(Ｗ１)は、前記気化器(７)の開閉弁(71)の開閉幅(Ｗ４)より大きいことを特徴とする内燃機関の吸気装置。     Combustion chamber ceiling surface of the cylinder head (32) facing the top surface (34a) of the piston (34) slidably fitted in the cylinder bore (31a) of the cylinder block (31) A combustion chamber (36) is formed between the intake valve port (40) and the exhaust valve port (41) open to the ceiling surface (32a) of the combustion chamber. Each of the intake port (42) and the exhaust port (43) is formed to extend while curving in a direction away from each other,
    An inlet pipe (6) is connected to the intake port (42) to form a continuous intake passage (80), and a carburetor (7) is connected upstream of the inlet pipe (6). (7) includes an open / close valve (71) that is displaceable so as to open and close the flow path (70) across the internal flow path (70);
    The intake passage (80) corresponds to the inner wall portion of the flow path (70) in which the front end (71a) is pressed when the on-off valve (71) of the carburetor (7) is closed in the direction of intake air flow. In an intake device for an internal combustion engine having a partition plate portion (85) that partitions the two intake passages (80B) and the first intake passages (80A) excluding the second intake passages (80B),
    The radial width (W1) of the intake passage (80) of the inlet pipe (6) is equal to the radial width (W2) of the first intake passage (80A) and the diameter of the second intake passage (80B). Including the width of the direction (W3),
    An internal combustion engine characterized in that a radial width (W1) of the intake passage (80) of the inlet pipe (6) is larger than an open / close width (W4) of an open / close valve (71) of the carburetor (7). Inhalation device.
  9. 　前記気化器(７)の前記開閉弁(71)の開閉幅(Ｗ４)は、前記第１吸気通路(80Ａ)の径方向の幅(Ｗ２)と略同じに形成されたことを特徴とする請求項８に記載の内燃機関の吸気装置。 The opening / closing width (W4) of the opening / closing valve (71) of the carburetor (7) is substantially the same as the radial width (W2) of the first intake passage (80A). Item 9. The intake device for an internal combustion engine according to Item 8.
PCT/JP2017/008538 2016-03-10 2017-03-03 Internal combustion engine intake device WO2017154783A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0725230U (en) * 1993-10-01 1995-05-12 富士重工業株式会社 Engine intake system
JPH08218875A (en) * 1995-02-15 1996-08-27 Yamaha Motor Co Ltd Exhaust gas recirculation device for engine
JPH11210478A (en) * 1998-01-30 1999-08-03 Yamaha Motor Co Ltd Intake device for engine
JP2000329016A (en) * 1999-05-17 2000-11-28 Yamaha Motor Co Ltd Intake passage structure for engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0725230U (en) * 1993-10-01 1995-05-12 富士重工業株式会社 Engine intake system
JPH08218875A (en) * 1995-02-15 1996-08-27 Yamaha Motor Co Ltd Exhaust gas recirculation device for engine
JPH11210478A (en) * 1998-01-30 1999-08-03 Yamaha Motor Co Ltd Intake device for engine
JP2000329016A (en) * 1999-05-17 2000-11-28 Yamaha Motor Co Ltd Intake passage structure for engine

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