JP2006258091A - Engine for leisure vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine for a leisure vehicle having an intake box of maximum capacity by maximally effectively using a usable space. <P>SOLUTION: This engine for the leisure vehicle has a combustion chamber 15, an intake passage 1 for supplying fresh air to this combustion chamber, and an intake pipe 2 connected to the upstream end side of this intake passage and supplying the fresh air to the intake passage. An engaging part 20R is formed on an outer peripheral surface of a connecting part between the intake pipe 2 and the intake passage 1. An engaging object part 4d engaging with the engaging part is arranged in the intake pipe or the intake passage or an opening 4P of an intake box 4 having an opening for penetrating these connecting part. The intake box 4 is arranged so as to cover the intake pipe from an external part by engaging the engaging part with the engaging object part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engine for leisure vehicles such as motorcycles, motor tricycles, rough terrain vehicles, and small planing boats.

  Leisure vehicles, such as motorcycles, tricycles, rough terrain vehicles, small planing boats, and other engines, may contain fresh air (fuel may be included) into the combustion chamber in the engine block. A vaporizer (used in a wide concept including the throttle body) for supplying a vaporizer (supplied in the range of the same) and an intake box (also called an airbox) for supplying clean fresh air to the vaporizer are attached ( Patent Document 1).

  Further, in the case of the leisure vehicle engine, there is almost no extra space around the engine as compared with an engine mounted on a four-wheeled vehicle or the like.

  By the way, in order for the engine to produce a desired output, it is desirable that the back pressure generated at the intake port of the carburetor is lower than a predetermined level, and the back pressure at the time of suction is made as low as possible. Engine output can be obtained.

  For this purpose, it is conceivable to increase the capacity of the intake box for supplying fresh air to the carburetor as much as possible.

However, in the case of a leisure vehicle, there is no room for a sufficiently large intake box, as described above. The present situation is that a necessary volume is obtained as a whole of these intake boxes by arranging the boxes (see Patent Document 2).
Japanese Patent No. 2578094. Japanese Patent Application Laid-Open No. 2003-176757.

  However, when a plurality of intake boxes are arranged as described above, pipes and the like for connecting the intake boxes are required, and accessory parts such as support brackets for the intake boxes are required.

  Also, among leisure vehicles, in the case of small vessels, etc., there are spaces for arranging a plurality of intake boxes as described above, but in the case of motorcycles, there are a plurality of such spaces. At present, it is difficult to obtain a space for arranging the intake box.

  The present invention is designed for a leisure vehicle engine equipped with an intake box having as large a capacity as possible by utilizing the available space as much as possible in the present day where weight reduction and simplification are currently being planned. The purpose is to provide.

The object of the present invention is solved by a leisure vehicle engine having the following configuration. That is, the leisure vehicle engine according to the present invention is connected to the combustion chamber, the intake passage for supplying fresh air to the combustion chamber, and the upstream end side of the intake passage, and supplies fresh air to the intake passage. In a leisure vehicle engine equipped with an intake pipe,
While forming an engaging portion on the outer peripheral surface of the connection portion between the intake pipe and the intake passage,
An engaged portion that engages with the engaging portion is provided in the opening of an intake box having an opening through which the intake pipe or intake passage or a connecting portion thereof passes, and the engaging portion and the engaged portion And an intake box is disposed so as to cover the intake pipe line from the outside.

  According to the leisure vehicle engine according to the present invention configured as described above, the end of the intake box can be brought as close as possible to the vicinity of the engine block (engine body), so that a dead space has conventionally been formed. The used space can be used effectively. In particular, this is a very preferable configuration for a leisure vehicle such as a motorcycle that does not have a space for providing an intake box in other portions.

  In the leisure vehicle engine, an insulator is interposed between the intake passage and the intake pipe, and the engagement portion is provided on the outer peripheral surface of the insulator. This is a preferable mode for implementation, such as an increase in the degree of freedom in selecting the material of the pipe line.

  In the leisure vehicle engine, a fixed band for fixing the intake passage side and the intake pipe side to each other is provided at the connection portion between the intake passage side and the intake pipe side. When the engaging portion is formed, the end portion of the intake box can be brought as close as possible to the engine block (engine body) side, which contributes to increasing the volume of the intake box. In such a case, it is desirable to interpose a heat insulating material between the engine block and the intake box, or to dispose a heat insulating material on the wall of the intake box on the engine block side.

  Further, in the leisure vehicle engine, a right-handed screw nut and a left-handed screw nut for fastening the fastening band are disposed (for example, fixed) at both ends of the stationary band, A tightening bolt is provided with a portion screwed into these nuts and a base end portion extending to the outside of the intake box. The tightening bolt allows the fixing band to be tightened from the outside of the intake box. With this configuration, the intake pipe line can be easily attached and detached from the intake passage side, and the engine can be easily assembled or maintained.

  In the leisure vehicle engine, if the intake pipe is formed by an intake passage of a throttle body, and the entire throttle body is accommodated in the intake box, the volume of the intake box can be increased. It becomes possible to enlarge as much as possible.

  In the leisure vehicle engine, when the engagement portion and the engaged portion are sealed in a labyrinth structure, the sealing performance with respect to the outside air side of the intake box can be improved.

  Further, in the leisure vehicle engine, if the portion through which the insulator and the insulator of the intake box penetrate is made of a flexible material, the sealing performance at this portion can be improved. This is a preferred embodiment.

  In the leisure vehicle engine, the engine includes a plurality of cylinders, and the intake pipe is provided for each cylinder or for each predetermined number of cylinders. In the multi-cylinder engine, a large volume intake box can be formed by providing a number of holes for passing through the intake passage or the insulator corresponding to the intake pipe or intake passage or the insulator. This is a preferable configuration.

  According to the leisure vehicle engine according to the present invention configured as described above, an intake box having a larger capacity than that of the conventional case can be obtained even in a leisure vehicle having a small space, such as a motorcycle. Can do.

  Hereinafter, a leisure vehicle engine according to the present invention will be specifically described with reference to the drawings, taking a four-cycle overhead cam type (OHC type) engine as an example.

  FIG. 1 is a schematic diagram showing the overall configuration of a leisure vehicle engine according to an embodiment of the present invention. FIG. 2 is an intake passage of the engine shown in FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing a schematic configuration of an intake passage, an intake conduit, and a throttle valve.

As shown in FIG. 1, an intake passage 1 is provided in a cylinder head 10 that forms a part of an engine block (engine body) of a four-cycle engine E according to the present embodiment. An air-fuel mixture is supplied into the combustion chamber 15 via the valve 12. The engine E according to this embodiment is a so-called 4-valve type engine E in which two intake valves 12 and two exhaust valves 14 are arranged in one cylinder. In FIG. 1, only one intake valve 12 and one exhaust valve 14 are shown for convenience.
The upstream end of the intake passage 1 is connected to a downstream end of an intake pipe line (generally called “intake manifold” or “throttle body”) 2, and a throttle valve 3 is provided in the intake pipe line 2. A predetermined angle range is rotatably arranged. Further, at least the upstream end portion of the intake pipe line 2 (in the case of this embodiment, specifically, all of the intake pipe line 2 as shown in FIG. 16) protrudes into the intake box 4. The fresh air in the intake box 4 is configured to be supplied to the intake pipe 2. The upstream end portion of the intake pipe 2 has a flare shape (funnel shape) that gradually expands toward the end side in order to improve intake efficiency.
Further, a fuel injection nozzle 13 (see FIG. 1) whose base end is connected to a fuel injection pump (not shown) is disposed upstream of the intake pipe 2 so that fuel is sucked at an appropriate timing. It is configured to be supplied to fresh air. In FIG. 1, 17 is a piston disposed in the cylinder 18, 19 is a crankcase, 22 is an exhaust passage, and 24 is an exhaust muffler. Further, although the ignition plug is not shown in FIG. 1, the ignition plug is disposed at a central portion of the cylinder head 10 surrounded by the two intake valves 12 and the two exhaust valves 14.

  Incidentally, as shown in FIG. 2, the intake passage 1 has an intake port (portion where the intake valve 12 is disposed) formed at the downstream end. This downstream end is connected to the two intake valves 12. Correspondingly, two intake ports are formed by bifurcating. On the other hand, the upstream end of the intake passage 1 serving as a connection end with the intake pipe 2 is formed as a single oval passage whose passage cross-sectional shape has a major axis and a minor axis (see FIG. 2). (See passage cross-sectional shape B, outlined by a two-dot chain line). The passage cross-sectional shape of the downstream end serving as the intake port and the downstream portion from the branched portion (branch portion) is substantially the same as the shape of the intake valve 12 (in this embodiment, a perfect circle shape). (Refer to the passage cross-sectional shape A outlined by the two-dot chain line in FIG. 2).

In the case of this embodiment, as shown in FIG. 2, the intake pipe 2 is formed in a tapered hole shape so that the passage cross-sectional area gradually decreases from the upstream end to the downstream end. Further, in this embodiment, the intake pipe 2 has an elliptical short axis from the taper angle α of the wall surface (see “d1” in FIG. 2) that appears when sectioned along the major axis of the ellipse. The taper angle β of the wall surface (see “d2b” in FIG. 3) of the downstream side portion of the throttle valve 3 that appears when the cross section is taken along the line is larger.
In addition, as shown in FIG. 3, the intake pipe 2 has a constant portion d2a upstream of the throttle valve 3 on the wall surface d2 of the intake pipe 2 which is shown by being cut along an elliptical short axis. The portion d2b on the downstream side of the throttle valve 3 is formed with another constant taper angle β (η1 <β).

The passage cross-sectional shape of the downstream end of the intake pipe 2 is an oval shape having a major axis and a minor axis, which is equal to the passage sectional shape of the upstream end of the intake passage 1 (two-dot chain line in FIG. 2). The passage cross-sectional shape B is outlined in FIG. 2), and the passage cross-section is configured not to change at the connection portion. In this embodiment, the intake pipe 2 is configured such that the cross-sectional area of the intake pipe 2 increases toward the upstream side (see the passage cross-sectional shapes C and D on the upstream side of the intake pipe 2). The cross-sectional shape of the passage in any part of the intake pipe 2 is an oval shape having a major axis and a minor axis.
Therefore, the shape of the throttle valve 3 (more precisely, the shape of the valve body 3A (see FIG. 5 or FIG. 7)) arranged to be openable and closable (rotatable) in the intake pipe 2 is also the intake air. It has the same ellipse shape composed of a major axis and a minor axis having substantially the same dimensions so that the pipe 2 can be substantially closed. Exactly, as shown in an enlarged view in FIG. 4, the dimension of the valve body 3A is slightly smaller than the dimension of the intake pipe 2 so that it can be smoothly opened and closed. Specifically, the dimension is about 0.05 mm to 0.20 mm smaller. More specifically, as shown in an enlarged view in FIG. 8 (b), when the throttle valve 3 is in a fully closed state, the wall surface (inner wall surface) of the intake pipe line 2 corresponds to this. The throttle valve 3 is cut obliquely so that an end face 3f is formed at the end 3a of the throttle valve 3 so that a parallel gap can be formed between the throttle valve 3 and the end 3a. By the way, as for the ratio of the length of the major axis and the minor axis of each elliptical shape of the intake pipe 2 and the throttle valve 3, the length of the minor axis is about 60 to 80% with respect to the major axis. Is preferred.

Therefore, in the engine according to the embodiment of the present invention configured as described above, the passage sectional shape from the intake pipe 2 to the intake passage 1 on the upstream side from the branch portion has substantially the same passage sectional shape. Therefore, even when the air-fuel mixture passes, the pressure loss does not change in this portion. Therefore, the air-fuel mixture is supplied to the intake port side in the cylinder head 10 without being disturbed as much as possible in this portion. The For this reason, it becomes an engine with high intake efficiency.
Further, although the exhaust passage 22 is not described, the exhaust passage is configured in the same manner, so that the engine has high exhaust efficiency.

Incidentally, as an actual configuration, as shown in FIG. 11, it is desirable that an insulator (holder) 20 is disposed between the intake pipe 2 and the intake passage 1 and is connected to the upstream end of the insulator 20. The shape of the outer peripheral cross section of the intake pipe 2 having an elliptical shape is preferably configured as follows. That is, as shown in FIG. 14, the shape of the outer peripheral cross section of the connection portion 2D of at least the intake pipe 2 connected to the insulator 20 side is continuous with positive values of the curvature of each part constituting the outer peripheral cross sectional shape. It is preferable to change the shape into an elliptical shape or a non-perfect circle (not shown). That is, when configured in this way, as will be described later, when the intake conduit 2 is connected to the intake passage 1 (see FIG. 11) side in the cylinder head 10, A highly sealable connection (connection structure) can be realized. Specifically, as shown in FIG. 11 and described later, this intake pipe line 2 is attached to the cylinder head 10 via an insulator 20 in this embodiment, but the upstream end of the insulator 20 The portion 20B and the downstream end portion of the intake pipe line 2 are overlapped in the longitudinal direction (in this embodiment, the upstream part of the insulator 20 is located outside the downstream end part of the intake pipe line 2). In a nested state). Then, as shown in FIG. 14 (or FIG. 11), the overlapping portion is replaced with a band 21 using a band (in this embodiment, a metal band: a kind of flexible band-shaped member) 21. When the bolt of the tightening bolt and the bolt of the nut pair 57 are tightened, a configuration in which a positive tightening force acts on any part around the band 21 can be realized. Therefore, if comprised in this way, connection with high sealing performance will be attained between the intake pipe 2 and the insulator 20. The material of the band 21 is not limited to a metal material, but may be other materials such as a resin material.
Further, in place of the above embodiment, although not shown, the upstream end of the insulator 20 is connected in a state of overlapping with the downstream end of the intake pipe 2 in the longitudinal direction, and the downstream of the intake pipe 2 As described above, the outer peripheral cross section of the end portion may be formed into an elliptical shape or a non-perfect circle (not shown) in which the curvature of each part constituting the outer peripheral cross section continuously changes with a positive value. Similar effects can be obtained.

  Further, as shown in FIG. 16, the upstream end of the intake passage 1 and the downstream end of the intake pipe line 2 are directly connected without interposing the insulator 20 (see FIGS. 11 and 14). May be. In such a configuration, the upstream end 1u of the intake passage 1 is formed so as to protrude from the cylinder head 10 of the engine E in a cylindrical shape, and the downstream end 2z of the intake pipe 2 is connected to the intake passage 1. The connection may be made by connecting in a state of being overlapped in the longitudinal direction so as to cover the outer peripheral side of the upstream end 1u, and tightening the overlapped portion with the band 21 from the outer peripheral side. In such a case, it is desirable that the intake pipe 2 is made of a heat-resistant hard plastic, and that a slit 55 along the longitudinal direction is provided at the downstream end 2z of the intake pipe 2. . In FIG. 16, reference numeral 57 denotes a tightening bolt and nut pair for tightening the band 21. In FIG. 16, an ellipse indicated by a broken line in the intake pipe 2 conceptually indicates the throttle valve 3.

Furthermore, the overall connection structure between the intake pipe 2 and the cylinder head 10 will be described with reference to FIGS. That means
As shown in FIG. 11, the upstream end of the intake passage 1 is opened on the side end surface of the cylinder head 10, and the front shape of the opening (the shape seen from the direction orthogonal to the opening) and the inner passage The above-described insulator 20 having the same cross-sectional shape 20A (or a continuous cross-sectional shape) is attached to the cylinder head 10 by a plurality of bolts 11 so as to communicate with the opening of the cylinder head 10. A cylindrical portion 20C is formed in the upstream portion of the insulator 20 as shown in an enlarged view in FIG. 12, and the downstream end portion 2D of the intake pipe 2 is formed in the cylindrical portion 20C. Is accommodated in a fitted state. A metal band 21 provided with the tightening bolt and nut pair 57 (see FIG. 11) is wound around the outer periphery of the cylindrical portion 20C of the insulator 20. Two ring-shaped flanges 20R are integrally projected outwardly from the cylinder head 10 (see FIG. 11). And this rib part 20R is comprised so that the two concave grooves 4d formed in the end surface of the opening part 4P of the said intake box 4 may be closely_contact | adhered.
In this case, the member 4D (see FIG. 13) including the insulator 20 and the opening 4P can be deformed because it is made of flexible rubber (or may be made of resin). The box 4 can be easily attached to the insulator 20, and high airtightness can be obtained at this attachment portion.

  Further, the intake box 4 will be described. In this embodiment, the intake box 4 is configured to accommodate two intake pipe lines 2 (see FIGS. 11 and 13) arranged side by side. As shown in FIG. 13, the intake box 4 is provided with another member (referred to as member 4 </ b> D) that is part of the intake box 4 and is different in material from the main body of the intake box 4. Two openings 4P are arranged side by side in 4D. The member 4D having the opening 4P and the other part of the intake box 4 are assembled as a physically integrated body by bonding, welding, or fitting.

In addition, the member 4D having the opening 4P is made of rubber in this embodiment, and includes a wall surface 4F of the main body portion of the intake box 4 around it, that is, a wall surface 4F other than the member 4D. The other parts are made of a highly rigid plastic (for example, ABS resin or polypropylene resin). However, it may be made of a similar material.
As described above, one end of the intake box 4 is positioned at the connection portion between the insulator 20 and the intake pipe 2, that is, one end of the intake box 4 is positioned close to the insulator 20 (position close to the engine body). ) Is an excellent configuration in that the capacity of the intake box 4 can be increased even in a limited space such as a motorcycle.

  By the way, as shown in FIG. 13, when the two intake pipes 2 and the corresponding insulators 20 are arranged side by side, on the outer peripheral side of the cylindrical portion 20C of the two insulators 20 arranged side by side, When each metal band 21 and two nuts 157B with opposite threads are fixed to both ends of the band 21 and fastened with the bands 21, the nuts 157B of the respective bands 21 are attached to the nuts 157B. It is desirable that one common tightening bolt 157A is disposed, the bolt 157A is rotated, and each nut 157B is moved on the bolt 157A to tighten the band 21. In such a case, the base end of the bolt 157A is positioned outside the intake box 4, and a “knob” 129 is formed integrally with the base end, and the “knob” 129 is rotated. Accordingly, it is more desirable to construct each band 21 so as to be tightened or loosened. That is, the intake box 4 can be fixed to or removed from the insulator 20 by simply rotating the “knob” 129. In such a configuration, a seal member is interposed between the bolt 157A and the through hole 4n of the intake box 4, or a maze structure is provided to ensure airtightness, which is a more desirable configuration. .

  In FIG. 11, the hole 25 having a small diameter is formed in the valve body 3A. In this embodiment, as shown in FIG. 1, only the fuel injection nozzle 13 ( This is because a small amount of air-fuel mixture can be supplied to the combustion chamber 15 (see FIG. 1) through the hole 25 even when the engine is idling due to the fact that the engine is idling. . Therefore, when the fuel injection nozzle is arranged on the downstream side of the valve body 3A, or when another fuel injection nozzle is also arranged on the downstream side, such a hole 25 is not necessary.

  In the engine having the above-described configuration, the throttle valve 3 can be rotated (openable and closable) as shown in FIGS. 7 and 8. The valve body 3A of the throttle valve 3 and the valve body 3A are rotatable. The pivot shaft 3B to be supported is formed as a single unit, and the pivot shaft 3B protrudes laterally from both ends of the valve body 3A, that is, the pivot shaft 3B at the center of the valve body 3A. If the configuration is such that the air-fuel mixture does not exist, the air-fuel mixture passing along the surface of the valve body 3A will not be disturbed. In particular, in the full throttle state, the air-fuel mixture passing through the valve body 3A flows smoothly. In this case, as shown in FIG. 8, the thicknesses of the end portions 3a on both sides farthest from the pivot shaft 3B of the valve body 3A are thinned and gradually increased toward the center side, and the both end portions Is configured in a round shape, a smoother air-fuel mixture flow can be obtained in the full throttle state.

  As described above and illustrated in FIG. 7, when the valve body 3 </ b> A and the pivot shaft 3 </ b> B are integrated, the intake pipe line 2 is separated from the intake pipe line 2 in the vertical direction (assembly). As shown in FIG. 7 shown in the previous state), it is divided into two parts vertically (or left and right or other directions), and the pivot shaft 3B is sandwiched between the two parts. .

  With respect to the configuration in which the intake pipe 2 is divided into two, as an embodiment different from FIG. 7, as shown in FIG. 9, in a direction orthogonal to the longitudinal direction of the intake pipe 2 (or in a direction having an arbitrary angle). It may be configured to be divided into two. In such a case, when the intake pipe 2 has a long dimension in the longitudinal direction, it is preferable in that it is easy to obtain a highly accurate passage cross-sectional shape.

  7 and 9, the both ends of the pivot shaft 3B are exposed to the outside, but at least one end may not be exposed. Such a non-exposed configuration is a preferred embodiment in that the sealing effect can be enhanced.

  Further, as an embodiment different from the above embodiment, the shape of the valve body 3A (and the intake pipe that houses the valve body 3A) may be an elliptical shape as shown in FIG. Even in such a case, the change in the pressure loss can be reduced as much as possible in the portion from the intake pipe to the intake passage as compared to a known circular shape such as a known intake pipe and valve body. The effect of this can be achieved.

  However, the intake pipe 2 and the valve body 3A having an oval shape shown in FIG. 5 are pivotally supported with respect to the intake pipe when the valve body is set in the intake pipe. Even if the shaft is slightly deviated in the longitudinal direction of the shaft, the linear portion 3p of the outer edge of the valve body is not affected by the displacement (displacement), and a desired gap is maintained with the wall surface of the intake pipe. It is preferable at the point which can do. In addition, in the case of an oval shape, the structure is basically composed of a circle and a straight line, so that the structure is excellent in productivity.

Further, as shown in FIG. 10, a flange portion 3K having a diameter larger than the diameter of the pivot shaft 3B is formed on the pivot shaft 3B side of the valve body 3A and the pivot shaft 3B of the throttle valve 3; In addition to the sealing effect of the seal member 7, when the seal member 7 is interposed on the outer side (end of the pivot shaft 3 </ b> B) of the bearing 3 </ b> G so that the throttle valve 3 can be rotated with respect to the intake pipe 2. Due to the labyrinth structure by the flange portion 3K, a preferred embodiment is also obtained in that a necessary and sufficient sealing effect can be obtained even when the above-described split structure such as “two splits” is adopted. Further, the flange portion 3K has a configuration effect (a function as a so-called “hit”) with the inner wall surface of the intake pipe 2 (in some cases, the intake passage).
Various parts of the intake pipe line 2 can be considered as such a “divided into two parts” plane. In addition to this, the connection surface between the intake passage 1 and the intake pipe line 2 can be divided into two parts. The dividing plane of "" is a simple preferred embodiment in terms of configuration.

Further, in the embodiment shown in FIG. 1, the fuel injection nozzle 13 is disposed upstream of the intake pipe 2, but instead of or in addition to this embodiment, as shown in FIG. A mounting hole 2h may be formed in a portion of the intake pipe 2 on the downstream side of the throttle valve 3, and the fuel injection nozzle 13 may be disposed in the mounting hole 2h. Specifically, the mounting hole 2h is formed in a portion of the intake pipe 2 on the downstream side of the throttle valve 3 so that the longitudinal direction of the hole is located on the downstream side. The mounting hole 2h is formed as a tapered hole having an enlarged diameter on the inner end side, and the taper angle T1 of the tapered hole is determined from the fuel injection nozzle 13 attached to the mounting hole 2h to the passage 2p of the intake pipe 2. It is configured to be larger than the so-called “spray angle” T2 of the fuel injected toward.
The fuel injection nozzle 13 is inserted into the mounting hole 2h so that the injection port 13h at the tip of the fuel injection nozzle 13 does not protrude from the inner wall surface 2w of the intake pipe 2, that is, the outer diameter from the inner wall surface 2w. It attaches in the state retreated to the direction (outer diameter direction of the intake pipe 2). Further, in this embodiment, the fuel injection nozzle 13 is arranged on the short axis of the intake pipe 2 (above the intake pipe 2 (upward) in FIG. 15). However, the fuel injection nozzle 13 may be disposed on the long axis of the intake pipe 2 of the intake pipe 2. In FIG. 15, E represents the engine, 1 represents the intake passage of the cylinder head 10, 12 represents the intake valve, 15 represents the combustion chamber, Ig represents a spark plug, and 21 represents a band for tightening.

  Moreover, in the said Example, although the reciprocating type 4 cycle type OHC engine was demonstrated to the example, this invention is applicable also to another 4 cycle engine, and can also be applied to a 2 cycle engine, Furthermore, it can be applied to a rotary engine.

  The aforementioned leisure vehicle engine according to the present invention can be used for various leisure vehicles. In particular, the engine is suitable for a motorcycle, a small planing boat, or a small ATV (rough terrain vehicle) in which the space for mounting the engine is limited.

  The engine for leisure vehicles according to the present invention can be used for various leisure vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an overall configuration of a leisure vehicle engine according to an embodiment of the present invention. It is a schematic block diagram which shows the cross-sectional shape of the principal part of the intake passage and intake pipe line of the engine shown in FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing a schematic configuration of an intake passage, an intake pipe line, and a throttle valve. FIG. 4 is a partial enlarged cross-sectional view of the portion showing the configuration of the throttle valve shown in FIG. 3 and the intake pipe in the vicinity thereof. It is the figure which looked at the valve body which shows the shape of the valve body of the throttle valve shown in FIG. 3, FIG. 4 from the front. It is the figure which looked at the valve body which shows the shape of the valve body concerning the Example different from FIG. 5 from the front. FIG. 6 is a view seen from the longitudinal direction of the pipe showing the configuration of the throttle valve having the oval valve body having the same front shape as that of FIG. 5 and a pivot shaft and the intake pipe having the throttle valve (two-part structure). . (A) is a sectional view of the throttle valve shown in FIG. 7 taken along the line IIIV-IIIV in FIG. 7, and (b) is an end of the valve body of the throttle valve shown in (a) (two-dot chain line of (a). FIG. It is the figure seen from the direction orthogonal to the pipe line longitudinal direction which shows the structure (two-part structure) of the intake pipe concerning the Example different from FIG. FIG. 8 is a partially enlarged view of a right end portion showing a configuration of a bearing portion of a throttle valve according to another embodiment different from FIG. 7. FIG. 3 is a cross-sectional view taken along the longitudinal direction of the intake pipe and the intake passage connected thereto, showing a structure for attaching the intake pipe to the cylinder head according to the embodiment of the present invention. It is an expanded sectional view of the connection part of an intake pipe line and an insulator shown in FIG. FIG. 13 is an XIII-XIII arrow view of FIG. 11 showing an intake box arranged so that one end is located at a connection portion between the intake pipe line and the insulator shown in FIG. 11. FIG. 12 is a cross-sectional view taken along the line XIIII-XIIII in FIG. 11 illustrating a configuration of a connection portion between the intake pipe line and the insulator illustrated in FIG. 11. It is a fragmentary sectional view of the fuel injection nozzle vicinity which shows the structure of the Example concerning the form which formed the attachment hole in the intake pipe and has arrange | positioned the fuel injection nozzle. FIG. 3 is a partially cutaway view showing a structure for attaching an intake pipe line to a cylinder head according to an embodiment of the present invention.

Explanation of symbols

1 ... Intake passage
2 ... Intake pipe
4 ... Intake box
4d: engaged portion
4P ... opening
15 ... Combustion chamber 20R ... Engagement part
E ... Engine

Claims (8)

In a leisure vehicle engine comprising a combustion chamber, an intake passage for supplying fresh air to the combustion chamber, and an intake pipe connected to the upstream end of the intake passage for supplying fresh air to the intake passage ,
While forming an engaging portion on the outer peripheral surface of the connection portion between the intake pipe and the intake passage,
An engaged portion that engages with the engaging portion is provided in the opening of an intake box having an opening through which the intake pipe or intake passage or a connecting portion thereof passes, and the engaging portion and the engaged portion And an intake box is disposed so as to cover the intake pipe line from the outside.   The engine according to claim 1, wherein an insulator is interposed between the intake passage and the intake pipe, and the engaging portion is provided on an outer peripheral surface of the insulator.   A fixing band for fixing the intake passage side and the intake pipe side to each other is provided with a fixing band, and the engagement portion is formed on the intake passage side from the fixing band. The engine according to claim 1 or 2, characterized in that   A right screw nut and a left screw nut for tightening the fixing band are provided at both ends of the fixing band, and a distal end portion is screwed into these nuts, and a proximal end portion is the intake air. 4. The engine according to claim 3, wherein a fastening bolt extending to the outside of the box is provided, and the fastening band can be fastened from the outside of the intake box by the fastening bolt.   The said intake pipe line is comprised by the intake passage of the throttle body, and this throttle body whole is accommodated in the said intake box, The claim of any one of Claims 1-4 characterized by the above-mentioned. Engine.   The engine according to any one of claims 2 to 5, wherein the engagement portion and the engaged portion are sealed in a maze structure.   The engine according to claim 6, wherein a portion of the insulator and the intake box through which the insulator passes is made of a flexible material. The engine includes a plurality of cylinders, the intake pipes are provided for each cylinder or for each predetermined number of cylinders, and the intake box passes through the intake pipe, the intake passage, or the insulator. The engine according to any one of claims 1 to 6, wherein a number of holes corresponding to the intake pipe line, the intake passage, or the insulator are provided.

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