JP2008215292A - Insulator structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulator structure enabling expansion of an adjustment range of output characteristics of an engine by enabling further reduction of the diameter of a restriction opening. <P>SOLUTION: This insulator 11 has a structure connecting an intake passage 5 in an internal combustion engine side connecting to a combustion chamber 4 and an intake passage 8 in a throttle device 3 side adjusting and setting flow rates of fuel and air to be supplied to the combustion chamber 4 to form an intake passage. The insulator 11 is provided with a restriction part 65 restricting a region which the fuel and the air pass through, and the restriction part 65 is formed in a funnel shape in which a passage section area gets smaller as it goes toward a downstream direction of the intake passage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an insulator structure in which an intake passage on an internal combustion engine side and an intake passage on a throttle device side are connected to guide fuel and air supplied from the throttle device to a combustion chamber.

  Conventionally, an intake passage is formed by connecting an intake passage on the side of an internal combustion engine and an intake passage on the side of a throttle device of a fuel injection type or a carburetor type that adjusts and sets the flow rates of fuel and air supplied to the internal combustion engine. Insulators that guide fuel and air supplied from a throttle device to a combustion chamber of an internal combustion engine while blocking engine vibration are used. The insulator is basically a connecting member that connects the intake passage on the internal combustion engine side and the intake passage on the throttle device side, and can change the shape of the internal passage without changing the appearance. Therefore, an orifice plate having a restriction opening for reducing the cross-sectional area of the passage is provided inside the insulator to restrict the amount of air flowing into the combustion chamber, so that engine output characteristics corresponding to the vehicle specifications can be obtained. Insulators are known (for example, see Patent Document 1).

JP-A-6-285872

  As described above, since the engine output characteristics can be changed by forming the limiting openings with different opening areas inside the insulator, there is a demand to further reduce the diameter of the limiting openings to expand the adjustment range of the output characteristics. is there. However, when the opening area of the restriction opening is reduced, a part of the mist-like fuel that flows down with the air cannot pass through the restriction opening but liquefies by colliding with the periphery of the opening and stays in the intake passage. . As a result, there is a problem that an air-fuel mixture having an unstable air-fuel ratio is supplied to the combustion chamber, the engine combustion efficiency is lowered, and drivability and emission performance cannot be improved.

  In addition, when the throttle device is a carburetor type, the fuel atomized by the intake airflow flows in the insulator together with the intake air, so the diameter is reduced to some extent by providing a restriction opening near the peripheral wall on the fuel discharge jet side. can do. However, in the case of a throttle device using a fuel injection valve that injects fuel into the intake passage, the atomized fuel is injected with a vector different from that of the intake airflow, so the restriction opening has a small diameter. There was a problem that it was particularly difficult to make it.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an insulator structure capable of further reducing the diameter of the restriction opening and expanding the adjustment range of the output characteristics of the engine.

  In order to solve the above-described problems and achieve the object, the present invention adjusts the flow rate of the fuel and air supplied to the combustion chamber, and the intake passage (for example, the intake passage 5 in the embodiment) connected to the combustion chamber. It is a structure of an insulator that connects an intake passage on the throttle device side to be set (for example, the intake passage 8 in the embodiment) to form a communicating intake passage and guides fuel and air supplied from the throttle device to a combustion chamber. The insulator is provided with a restricting portion for restricting the passage region of the fuel and air, and this restricting portion is formed in a funnel shape in which the cross-sectional area of the passage becomes smaller toward the downstream side of the intake passage.

  In the present invention, the throttle device includes a fuel injection valve (for example, the injector 35 in the embodiment) that injects fuel into the intake passage, and the fuel injection direction of the fuel injection valve is downstream of the intake passage. In addition to being provided in an inclined posture inclined toward the direction, the limiting portion is formed to open toward the fuel injection port in the fuel injection valve.

  In addition, the insulator has a partition wall that is connected to an outer cylinder part that covers the outer periphery and partitions the intake passage into an upstream side and a downstream side, and the restriction part is formed on the partition wall by integral molding with the outer cylinder part It is preferred that

  Alternatively, the insulator has a plate-like member (for example, the orifice plates 60, 70, 80 in the embodiment) that partitions the intake passage into the upstream side and the downstream side, and the restricting portion is formed in the plate-like member. It is preferable.

Note that the opening of the restricting portion (for example, the restricting openings 67, 77, 77 ′, 87 in the embodiment) is the inner diameter center line (for example, the center line C in the embodiment) of the connection portion with the intake passage on the throttle device side in the insulator. ₈ ) The fuel injection valve side (the side where the fuel injection valve is disposed) is unevenly distributed with respect to the intake passage on the internal combustion engine side in the insulator, and the connection portion with the inner diameter center line is on the anti-fuel injection valve side It is preferably formed offset to the side opposite to the side where the fuel injection valve is disposed.

  Further, it is desirable that the restricting portion opens at an upper position in the intake passage, and a communication hole is formed below the restricting portion to communicate the upstream side and the downstream side of the restricting portion along the inner wall surface of the outer cylinder portion.

  According to the configuration in which the restricting portion is provided in the insulator, and the restricting portion is formed in a funnel shape in which the cross-sectional area of the passage becomes smaller toward the downstream side of the intake passage, the intake air and the atomized fuel are in the funnel-like restricting portion. Is flown along the wall surface of the restriction portion. For this reason, the mist-like fuel can be efficiently guided to the intake passage on the internal combustion engine side, thereby further reducing the diameter of the restriction opening and extending the adjustment range of the output characteristics of the engine.

  When a fuel injection type throttle device equipped with a fuel injection valve is used, the fuel injection valve is provided in an inclined posture in which the injection direction is inclined toward the downstream direction of the intake passage, and the restricting portion is injected by the fuel injection valve. According to the configuration in which the opening is formed toward the mouth, the vector direction of the intake airflow and the vector direction of the injected fuel can be brought close to each other, and is the most restrictive part with respect to the spray shape spreading in a conical shape from the injection port. The atomized fuel in the near region (for example, the upper region in the embodiment) can flow down along the funnel shape of the restricting portion. For this reason, even in a fuel injection type throttle device in which the passage rate of the fuel becomes a problem and it is difficult to reduce the diameter of the restricting portion, the injected fuel can be efficiently guided to the intake passage on the internal combustion engine side. The diameter of the opening can be reduced, and the adjustment range of the engine output characteristics can be expanded.

  In addition, according to the configuration in which the partition wall for partitioning the intake passage into the upstream side and the downstream side is provided inside the insulator, and the limiting portion is formed in the partition wall by integral molding with the outer cylinder portion, the insulator structure is simplified and the production process Can be simplified, and productivity can be improved. On the other hand, according to the configuration in which the plate-like member that partitions the intake passage into the upstream side and the downstream side is provided inside the insulator, and the limiting portion is formed in the plate-like member, the plate-like members having different opening areas and opening shapes are molded. Thus, a plurality of types of insulators corresponding to engine characteristics can be easily produced without changing the mold of the insulator.

  The opening of the restricting portion is unevenly distributed on the fuel injection valve side with respect to the inner diameter center line of the connecting portion on the throttle device side in the insulator, and the connecting portion with the intake passage on the internal combustion engine side of the insulator is opposite to the inner diameter center line. According to the configuration formed by offsetting in the direction, since the intake passage on the internal combustion engine side is formed offset in the vector direction of the injected fuel, the injected fuel flows smoothly into the vicinity of the center of the intake passage on the internal combustion engine side. In addition, the diameter of the connecting portion on the internal combustion engine side can be reduced while the intake passage from the throttle device to the combustion chamber has a gently curved shape.

  According to the configuration in which the restricting portion is formed at an upper position in the intake passage, and the communication hole that communicates the upstream side and the downstream side of the restricting portion along the inner wall surface of the outer cylinder portion is formed below the restricting portion. Even if liquefied fuel is produced in contact with the restriction part, it is possible to prevent the fuel from staying, and the communication hole and the restriction part are arranged apart from each other, so that the staying gas near the communication hole blows back the intake air. It becomes difficult to receive, and the air-fuel mixture can be stabilized and the engine performance can be improved.

  Therefore, according to the present invention, it is possible to provide an insulator structure capable of further reducing the diameter of the restriction opening and expanding the adjustment range of the output characteristics of the engine.

  Hereinafter, an insulator structure according to the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 show a configuration example when the insulator structure according to the present invention is applied to a motorcycle. First, an outline of an arrangement configuration of the insulator will be described with reference to these drawings. For convenience of explanation, unless otherwise specified, the arrow U direction appended to FIG. 1 will be referred to as upward, and the arrow R direction (rear of the vehicle body) will be referred to as right.

The insulator 11 is provided between the engine 2 that generates power and the throttle device 3 that adjusts and sets the flow rates of fuel and air supplied to the engine 2.
An engine-side intake passage 5 connected to the combustion chamber 4 and a throttle device-side intake passage 8 connected to the air cleaner 7 are connected to form a communication intake passage, and fuel and air supplied from the throttle device 3 are supplied to the combustion chamber. Guide to 4.

  The engine 2 exemplifies an over head camshaft (OHC) type water-cooled engine, and the cylinder head 21 is formed with an intake passage 5 and an exhaust passage 6 connected to the combustion chamber 4, and is opened to the combustion chamber 4. An intake valve 22 that opens and closes the intake port 5p and an exhaust valve 23 that opens and closes the exhaust port 6p that opens to the combustion chamber 4 are supported to be slidable in the vertical direction, and are interposed between the cylinder head 21 and the cylinder head 21. The valve springs 24, 24 are always urged upward. The upper ends of the intake valve 22 and the exhaust valve 23 are pivotally supported by the cylinder head 21 and supported by rocker arms 26a and 26b that are swung by cams formed on the camshaft 25, respectively. The rocker arms 26a and 26b are swung by the rotation of the camshaft 25 connected via a cam chain and a sprocket (not shown), and the intake valve 22 and the exhaust valve 23 are pushed down in response to the rocking of the rocker arm. 5p and the exhaust port 6p are opened and closed. That is, the intake valve 22 and the exhaust valve 23 are raised and lowered according to the raising and lowering position of the piston 29 connected to the crankshaft 28 via the connecting rod 27, and the intake port 5p and the exhaust port 6p are synchronized with the rotation of the crankshaft 28. Is opened and closed.

  The throttle device 3 is a fuel injection type throttle device using an injector (fuel injection valve) as a fuel discharge means. The throttle device 3 is perpendicular to the pipe axis of the intake passage 8 in the throttle body 31 in which the intake passage 8 is formed. A disc-shaped throttle valve 32 that is swingably mounted about an axis extending in a direction (a direction orthogonal to the drawing in both figures) and opens and closes the intake passage 8, and is provided on the downstream side of the throttle valve 32. And an injector 35 for injecting fuel.

The injector 35 has an inclined posture in which the fuel injection direction is inclined toward the downstream direction of the intake passage 8, more specifically, the fuel injection port 35 a faces an opening formed in the pipe wall of the intake passage 8. The center line C _{35 of the} injected fuel that is injected conically from the injection port _{35 a} is fixed to the throttle body 31 in such a mounting posture that smoothly contacts the center line C ₅ of the engine-side intake passage 5 that curves in an arc. (See FIG. 5).

  The fuel injection by the injector 35 is controlled by an ECU (Electronic Control Unit) that controls the operation of the engine 2, and the engine 2 (corresponding cylinder in the case of a multi-cylinder engine) is in the intake stroke, so that the intake valve 22 is opened. Thus, mist-like fuel is injected from the injection port 35a. The discharge amount of the injected fuel is set according to the engine speed, the valve opening of the throttle valve 32, the intake pressure, and the like. Specifically, it is formed in a map shape corresponding to each parameter as described above. The fuel injection time is set based on a fuel injection map stored in advance in a ROM in the ECU. For this reason, mist-like fuel is injected toward the diagonally downstream direction directed to the intake passage 5 on the engine side in an appropriate injection time according to the driving state (required air-fuel ratio) of the engine 2. The air cleaned by the air cleaner 7 and adjusted in flow rate by the throttle valve 35 and the fuel injected from the injector 35 flow through the restriction opening 67 of the insulator 11 and flow into the intake passage 5 on the engine side while being mixed. .

  The engine-side intake passage 5 is curved in a smooth circular arc shape and is connected to the combustion chamber 4. Air and fuel flowing into the intake passage 5 through the restriction opening 67 are further uniformly mixed in the passage. The air then flows down the intake passage 5 and is supplied to the combustion chamber 4 through the intake port 5p. Then, after the homogenized air-fuel mixture is compressed by the piston 29 in the compression stroke, it is ignited and burned by a spark plug (not shown) attached to the cylinder head 21, and the crankshaft is connected via the piston 29 and the connecting rod 27. 28 is rotated. The exhaust gas after combustion is pushed out by the piston 29 in the exhaust stroke, and is discharged outside through the exhaust port 6p through the exhaust passage 6.

  Thus, an external view of an insulator that is inserted between the engine 2 and the throttle device 3 and connects the intake passage 5 on the engine side and the intake passage 8 on the throttle device side is shown in FIG. ) Is a vertical cross-sectional view of the insulator 11 of the first embodiment along the direction in which the intake passage extends (cross-sectional view taken along arrow IVa in FIG. 4B), and FIG. 4B is a view from the throttle device 3 side. A front view of the insulator 11 is shown.

  The insulator 11 has an outer cylinder portion 51 that covers the outer periphery and has a cylindrical shape as a whole, and is formed integrally with an orifice plate 60 embedded in an annular partition wall 55 formed inside. On one end side of the partition wall 55 (on the right end side in FIG. 4 (a)), an engine connection portion 52 that is fitted and connected to a stepped cylindrical intake hole protrusion 42 that protrudes from the cylinder head 21, and the like. A throttle connection portion 53 is formed on the end side (left end side in the figure) to be fitted and connected to a stepped cylindrical connector portion 43 formed in the throttle device 3, and the outer peripheral side of these connection portions 52 and 53. In addition, band locking portions 54a and 54b around which the fastening bands 44a and 44b are wound are formed.

  When the engine connection portion 52 is fitted and connected to the intake hole protrusion 42 of the engine 2 and the connector portion 43 of the throttle device 3 is fitted and connected to the throttle connection portion 53, the intake passage on the engine side is sandwiched between the orifice plate 60. 5 and the intake passage 8 on the throttle device side are connected, and by tightening the fastening bands 44a and 44b wound around the band locking portions 54a and 54b, the fitting connection portion is tightly sealed without generating a gap. Connected. The insulator 11 is integrally formed by insert molding in which the peripheral edge of the orifice plate 60 is molded using a rubber material having high oil resistance and weather resistance, and the vibration of the engine 2 is cut off and is not directly transmitted to the throttle device 3.

  The orifice plate 60 provided in the partition wall 55 includes a flat disk-shaped plate portion 61 that partitions the intake passage into the upstream side (throttle device 3 side) and the downstream side (engine 2 side), and the center of the plate portion 61. A restriction portion 65 provided in the vicinity for restricting the passage region of fuel and air, a communication hole 63 formed through the plate portion 61 in the vicinity of the periphery of the plate portion 61, and the like, for example, having a plate thickness of about 1 mm It is composed of aluminum alloy plate or stainless steel plate. The communication hole 63 is formed in the shape of a long hole that communicates the upstream side and the downstream side along the bottom wall surface of the partition wall 55, and when liquefied fuel is generated in the intake passage, the communication hole 63 is caused to flow down. Prevent stagnation.

  The restricting portion 65 is formed in a funnel shape or bell mouth shape in which the passage cross-sectional area decreases toward the downstream direction of the intake passage (leftward in FIG. 4A), and is squeezed from the plate portion 61 to the downstream side. A circular restriction opening 67 is formed at the protruding end portion so as to be connected to a smooth conical or arcuate suction wall 66. For this reason, the fluid flowing through the intake passage (the gas-liquid mixed fluid of air and mist fuel) is rectified by the rectifying action of the restricting portion 65 and flows smoothly along the suction wall surface 66. Therefore, the mist-like fuel can be efficiently guided to the intake passage 5 on the engine side. Further, since the restriction opening 67 is formed at the protruding end portion that is squeezed and raised downstream from the plate portion 61, a particulate component such as a fuel component or carbon with respect to return of intake air from the intake passage 5 on the engine side. Can be prevented to prevent the backflow, thereby preventing the throttle device 3 from being soiled.

Here, as shown in FIGS. 4 and 5, the shape of the suction wall surface 66 is not axially symmetric with respect to the center line C ₆₇ passing through the center of the restriction opening 67, and the injector 35 disposed above the intake passage 8. It is formed in an eccentric funnel shape that is widened upwardly toward the injection port 35a. The injection port 35a of the injector 35 is provided in the vicinity of the peripheral edge (near the upper pipe wall) of the throttle valve 32 on the intake air side. Therefore, the vector direction of the intake airflow and the vector direction of the injected fuel can be made close to each other, and the fuel in the region closest to the orifice plate 60 with respect to the injected fuel that spreads in a conical shape obliquely downstream from the injection port 35a. Can flow smoothly along the eccentric funnel-shaped suction wall surface 66 (see the outline Fj of the injected fuel indicated by the two-dot chain line in FIG. 5).

In FIG. 4, the inner diameter center line of the throttle connection portion 53 (that is, the center line of the intake passage 8 on the throttle device 3 side) C ₈ , the center line C ₆₇ of the restriction opening 67, and the inner diameter center of the engine connection portion 52. As indicated by the line (namely, the center line of the intake passage 5 on the engine 2 side) C ₅ , the restriction opening 67 is in relation to the inner diameter center line (center line of the intake passage 8) C ₈ of the throttle connection portion 53. unevenly distributed upward toward an injector side, the engine connection portion 52 is formed to be offset downward is anti injector side in relation to the C ₈ (the center line of the intake passage 8) inside diameter center line of the throttle connecting portion 53 Yes. In other words, the intake passage 5 on the engine side is arranged offset from the intake passage 8 on the throttle device 3 side in the vector direction (diagonally downward) of the injected fuel. Therefore, the fuel that has been injected obliquely downward and passed through the restriction opening 67 flows into the vicinity of the center of the passage in the intake passage 5 on the engine side, and the gas-liquid mixed fluid that has passed through the restriction opening 67 flows down smoothly. Can be made. In addition, the insulator 11 can be made compact by reducing the diameter of the engine connection portion 52 while making the intake passage 5 connected from the throttle device 3 to the combustion chamber 4 a gentle curve.

Further, in the insulator 11, the restriction opening 67 is separated from the communication hole 63 and provided on the opposite side to the inner diameter center line C ₅ of the engine connection portion 52. For this reason, the flow of the gas in the vicinity of the communication hole 63 is suppressed and it is difficult to be affected by the blow-back of the intake air, thereby suppressing the entrainment of the staying gas.

  As described above, according to the insulator 11, the mist-like fuel can be efficiently guided to the intake passage 5 on the engine side, so that even if the injector type throttle device is used, the restriction opening 67 The diameter can be reduced, and the adjustment range of engine output characteristics can be expanded.

  Next, an insulator structure according to another embodiment of the present invention will be described with reference to FIGS. FIGS. 6 to 9 show cross-sectional views of the insulators 12 to 15 of the second to fifth embodiments corresponding to FIG. 4A, and other configurations except that the configuration of the limiting portion is different. The part is the same as that of the insulator 11 of the first embodiment. Therefore, the same parts are denoted by the same reference numerals and redundant description is omitted, and the insulator of each embodiment will be described focusing on the configuration of the limiting unit.

In the insulator 12 of the second embodiment shown in FIG. 6, a partition wall 55 ′ connected to the outer cylinder part 51 is formed by dividing the intake passage into an upstream side and a downstream side, and the restriction part 75 and the communication hole 73 are provided in the outer cylinder. It is formed by integral molding with the partition wall 55 ′ together with the part 51. That is, in the insulator 12, an eccentric funnel-shaped suction wall surface 76 similar to the suction wall surface 66 described above is formed integrally with the partition wall 55 ′, and the restriction opening 77 having the center line C ₇₇ as the opening center is formed in the downstream partition wall surface. Is formed. According to such a configuration, since it is not necessary to separately manufacture an orifice plate and insert mold, it is possible to simplify the production process and improve productivity.

In the insulator 13 of the third embodiment shown in FIG. 7, the communication hole 73 and the suction wall surface 76 in the restricting portion 75 are integrally formed with the partition wall 55 ′ together with the outer cylinder portion 51, similarly to the insulator 12 of the second embodiment. Is done. On the other hand, a restriction opening 77 ′ with the center line C ₇₇ as the center of opening in the restriction part 75 is provided in a thin flat orifice plate 70 which is insert-molded on the partition wall 55 ′. 75 is constituted. According to such a configuration, the configuration of the orifice plate 70 can be simplified, the shape and size of the restriction opening 77 ′ can be maintained with high accuracy, and the orifice plate having a different opening area and shape can be used. The mold of the insulator 13 can be shared for the range.

In the insulator 14 of the fourth embodiment shown in FIG. 8 and the insulator 15 of the fifth embodiment shown in FIG. 9, the restricting portion 85 and the communication hole 83 are provided in the plate thickness direction inside the thick disc-shaped orifice plates 80 and 80 ′. This is a configuration example formed, for example, formed integrally by a molding means such as aluminum die cast, and a suction wall surface is formed by adding a cutting process as necessary, and then the partition wall 55 is insert molded. That is, in the insulators 14 and 15, an eccentric funnel-like suction wall surface 86 similar to the suction wall surfaces 66 and 76 described above is formed as a channel wall surface that penetrates the orifice plates 80 and 80 ′, and is smoothly connected to the suction wall surface 86. A limiting opening 87 is formed in the downstream plate surface with the center line C ₈₇ as the opening center. The insulator 15 of the fifth embodiment is a configuration example in which a receiving port 88 for receiving injected fuel is formed by projecting the suction edge of the restricting portion 85 to the upstream side. According to such a structure, in addition to being able to manufacture and maintain the shape and size of the restricting portion with higher precision than the insulator 11 of the first and third embodiments, the wall surface is difficult to draw by thin plate. It is possible to create a shape, and by using orifice plates having different opening areas and shapes, it is possible to easily produce an insulator according to engine characteristics without changing the mold of the insulators 14 and 15. it can.

  As shown in the insulator 16 shown in FIG. 10, the upper portion of the partition plate 90 is bulged and formed on the upstream side to form an upward receiving plate portion 91 that faces the injector 35, and a plate surface is provided on the receiving plate portion 91. An insulator may be configured by opening a limiting opening 97 that penetrates. Alternatively, a funnel-shaped restricting portion that extends obliquely downward to the left in accordance with the fuel injection direction may be protruded from the receiving plate portion 91, and a restricting opening may be formed at the lower end of the restricting portion.

  Therefore, in the insulators 12 to 16 described above, similarly to the insulator 11 of the first embodiment, the mist-like fuel can be efficiently guided to the intake passage 5 on the engine side, thereby reducing the diameter of the restriction opening. As a possibility, the adjustment range of the output characteristics of the engine can be expanded.

  In the above, as a preferred embodiment to which the insulator structure according to the present invention is applied, a configuration example applied to an internal combustion engine having an injector type throttle device 3 has been shown. However, for an internal combustion engine having a carburetor type throttle device, Thus, it can be applied by changing the orientation of the funnel-shaped restricting portion in accordance with the formation position of the fuel discharge jet and the flight of the fuel. Further, the present invention is not limited to motorcycles, but can be similarly applied to internal combustion engines such as four-wheel automobiles and special vehicles, and similar effects can be obtained.

It is a side view which shows the arrangement | positioning position of the insulator at the time of applying the insulator structure which concerns on this invention to a motorcycle. It is a sectional side view which shows the positional relationship of an engine and a throttle apparatus, and an insulator. It is an external view of the said insulator. (a) A cross-sectional view of the insulator according to the first embodiment along the direction in which the intake passage extends (a cross-sectional view taken along arrow IVa in FIG. (b)), and (b) the insulator viewed from the throttle device side. It is a front view. It is sectional drawing which shows the relationship between the fuel injection of the injector with respect to an intake passage, and the limiting part of an insulator. It is sectional drawing of the insulator of 2nd Embodiment. It is sectional drawing of the insulator of 3rd Embodiment. It is sectional drawing of the insulator of 4th Embodiment. It is sectional drawing of the insulator of 5th Embodiment. It is sectional drawing of the insulator which shows the other structural example.

Explanation of symbols

C ₅ Inner diameter center line of engine connection C ₈ Inner diameter center line of throttle connection C ₃₅ Center line of injected fuel C ₆₇ Center line of restricted opening 2 Engine (internal combustion engine)
3 Throttle device 4 Combustion chamber 5 Engine side intake passage 8 Throttle device side intake passage 11 Insulator (first embodiment)
12 Insulator (second embodiment)
13 Insulator (Third Embodiment)
14 Insulator (4th Embodiment)
15 Insulator (5th Embodiment)
31 Throttle body 32 Throttle valve 35 Injector (fuel injection valve, 35a injection port)
51 outer cylinder part 52 engine connection part (connection part with engine side intake passage)
53 Throttle connection (connection with intake passage on throttle device side)
55, 55 'partition wall 60 orifice plate (plate-like member)
63 Communication hole 65 Restriction part 67 Restriction opening 70 Orifice plate (plate-like member)
73 Communication hole 75 Restriction part 77, 77 'Restriction opening 80 Orifice plate (plate-like member)
83 Communication hole 85 Restriction part 87 Restriction opening

Claims (6)

An intake passage is formed by connecting an intake passage on the internal combustion engine side connected to the combustion chamber and an intake passage on the throttle device side for adjusting and setting the flow rates of fuel and air to be supplied to the combustion chamber. A structure of an insulator for guiding the supplied fuel and air to the combustion chamber;
The insulator is provided with a restricting portion for restricting a passage region of the fuel and air,
The insulator structure according to claim 1, wherein the restricting portion is formed in a funnel shape in which a cross-sectional area of the passage becomes smaller toward a downstream direction of the intake passage. The throttle device has a fuel injection valve that injects fuel into the intake passage,
The fuel injection valve is provided in an inclined posture in which the injection direction of the fuel is inclined toward the downstream direction of the intake passage,
The insulator structure according to claim 1, wherein the limiting portion is formed to open toward a fuel injection port in the fuel injection valve. Inside the insulator, there is a partition wall that is connected to an outer cylinder portion that covers the outer periphery and partitions the intake passage into an upstream side and a downstream side,
The insulator structure according to claim 2, wherein the limiting portion is formed on the partition wall by integral molding with the outer cylinder portion. Inside the insulator, there is a plate-like member that partitions the intake passage into an upstream side and a downstream side,
The insulator structure according to claim 2, wherein the limiting portion is formed on the plate-like member. The opening of the restriction portion is unevenly distributed on the fuel injection valve side with respect to the inner diameter center line of the connection portion with the intake passage on the throttle device side in the insulator,
The connection part with the intake passage by the side of the said internal combustion engine in the said insulator is offset and formed in the anti-fuel-injection valve side with respect to the said internal-diameter centerline, The Claim 3 or Claim 4 characterized by the above-mentioned. Insulator structure. The restricting portion opens to an upper position in the intake passage,
6. The communication hole according to any one of claims 2 to 5, wherein a communication hole is formed below the restriction portion to communicate the upstream side and the downstream side of the restriction portion along the inner wall surface of the outer cylinder portion. An insulator structure according to claim 1.

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