JP7229334B2 - Intake structure of internal combustion engine - Google Patents

Description

The present invention relates to an intake structure for an internal combustion engine.

2. Description of the Related Art In an internal combustion engine that injects fuel into an intake port using an injector (fuel injection valve), fuel may adhere to the peripheral wall of the intake port, which may reduce the combustion efficiency of the internal combustion engine. As a countermeasure, Patent Document 1 discloses a structure in which an intake port is formed with a portion that promotes diffusion and vaporization of fuel.

JP 2015-190373 A

In order to efficiently supply the fuel injected from the injector to the combustion chamber, it is effective to arrange the injector as close to the combustion chamber as possible. However, in order to place the injector closer to the combustion chamber, there is a structural problem related to interference with the cylinder head and head cover.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure that allows the injector to be positioned closer to the combustion chamber.

According to the present invention of claim 1,
a passage member (11) connected between a cylinder head (32) provided with a head cover (31) and a throttle (12) to form an intake passage (11a);
a mounting boss (113) provided in the passage member (11) to which an injector (16) for injecting fuel is mounted;
An intake structure (10) for an internal combustion engine (3) mounted on a straddle-type vehicle (1), comprising:
The passage member (11) is
a bending portion (110a) that bends the passage direction of the intake passage (11a) in the vehicle width direction of the straddle-type vehicle (1);
a flange portion (111) having a connection surface (111a) connected to the cylinder head (32),
The mounting boss (113) is
formed integrally with the flange portion (111) at a position biased outward (OUT) from the inner side (IN) in the inward-outward direction (BD) of the bend of the bent portion (110a), and
When the passage member (11) is viewed from the connecting surface (111a) side, the passage member (11) protrudes in a direction (L2) intersecting with the cylinder axial direction (L1'),
The cylinder head (32) is
a connection surface (32a) to which the connection surface (111a) of the passage member (11) is connected;
a first avoidance portion (32b) formed adjacent to the connection surface (32a) and avoiding the injector (16);
There is provided an intake structure for an internal combustion engine characterized by:

According to the present invention of claim 2,
The mounting boss (113) has a hole (113a) into which the injector (16) is inserted and defines a fuel injection direction (L2) of the injector,
The axial direction (L2) of the hole (113a) is offset from the center line (CT) of the intake passage (11a).

According to the present invention of claim 3,
The throttle (12) is attached to an upstream end (112) of the passage member (11),
The drum portion (121) of the throttle (12) is positioned inside (IN) in the inward-outward direction (BD) of the bend of the bend (110a).

According to the present invention of claim 4,
The passage member (11) is
a first intake passage (11a), which is the intake passage;
forming a second intake passage (11b) separate from the first intake passage;
The intake port (321) of the cylinder head (32) is
a first passageway (321a) communicating with the first intake passageway (11a);
a second passageway (321b) communicating with the second intake passageway (11b);
a confluence passageway (321c) in which the first passageway (321a) and the second passageway (321b) merge on the downstream side,
The axial direction (L2) of the hole (113a) passes through the confluence passageway (321c).

According to the present invention of claim 5,
The head cover (31) is adjacent to the connecting surface (32a) of the cylinder head (32) and overlaps with the cylinder head (32) as a first avoiding portion that avoids the injector (16). Including (31a).

According to the present invention of claim 6,
The injector (16) is provided with a connection portion (16a) to which a fuel pipe is connected,
The connecting portion (16a) faces inward (IN) in the medial-lateral direction (BD).

According to the first aspect of the present invention, the amount of protrusion of the mounting boss can be suppressed, and the injector can be arranged at a position closer to the cylinder head, that is, the combustion chamber. Moreover, it is possible to reduce restrictions on the arrangement of other parts around the mounting boss. Also, it is easy to attach the injector. Furthermore, the injector can be arranged at a position closer to the combustion chamber while avoiding interference with the cylinder head .

According to the present invention of claim 2, the fuel injection direction of the injector can be oriented in a direction closer to the combustion chamber.

According to the third aspect of the present invention, the space inside the bent portion can be utilized as a space for arranging the throttle drum.

According to the fourth aspect of the present invention, in the case of adopting an intake structure that generates tumble in the combustion chamber, it is possible to promote the mixing of the intake air and the fuel after joining.

According to the fifth aspect of the present invention, the injector can be arranged at a position closer to the combustion chamber while avoiding interference with the head cover.

According to the sixth aspect of the present invention , it is possible to suppress the protrusion of the fuel pipe in the vehicle width direction.

1 is a side view of a straddle-type vehicle that is an application example of the present invention; FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; FIG. 3 is a cross-sectional view along the line BB of FIG. 2; CC line sectional view of FIG. The top view of a passage member. The figure which looked at the passage member of FIG. 5 from the one connection surface side. The figure which looked at the passage member of FIG. 5 from the other connection surface side. FIG. 7 is a cross-sectional view taken along line DD of FIG. 6; EE line cross-sectional view of FIG. FIG. 5 is a sectional view taken along line FF of FIG. 4;

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined arbitrarily. Also, the same or similar configurations are denoted by the same reference numerals, and redundant explanations are omitted.

<Saddle type vehicle>
FIG. 1 is a side view of a straddle-type vehicle 1 that is an application example of the present invention. In this embodiment, an example in which the present invention is applied to a straddle-type vehicle 1 will be described, but the present invention can also be applied to other types of vehicles such as four-wheeled vehicles.

The straddle-type vehicle 1 is a naked type motorcycle. The straddle-type vehicle 1 may be referred to as the vehicle 1 hereinafter. In each figure, Fr, Rr, U, D, L, and R indicate the front side, the rear side, the upper side, the lower side, the left side, and the right side, respectively, based on the forward direction of the vehicle 1 . Further, the terms "upstream" and "downstream" refer to the upstream and downstream sides in the airflow direction of the intake air unless otherwise specified.

A vehicle 1 includes an internal combustion engine 3 supported by a vehicle body frame 2 between front wheels FW and rear wheels RW. The front wheels FW are steering wheels, and the rear wheels RW are drive wheels rotated by the driving force of the engine 3 . A front wheel FW is rotatably supported by a front fork 4 .

The body frame 2 includes a front fork 4 and a head pipe 20 that steerably supports a handlebar 5 connected to the front fork 4, a main frame 21 extending rearward from the head pipe 20, and left and right arms extending downward from the rear portion of the main frame 21. A pair of lower frames 22, a down frame 23 extending downward from the front portion of the main frame 21, a pair of left and right seat rails 24 extending rearward from the rear portion of the main frame 21, and a stay 25 connecting the seat rails 24 and the lower frame 22 are provided. include.

A swing arm 6 is swingably supported by the main frame 21 via a pivot frame 26 . The swing arm 6 rotatably supports the rear wheel RW. The driving force of the internal combustion engine 3 is transmitted to the rear wheels RW via a chain (not shown). A rear cushion 7 is provided between the swing arm 6 and the seat rail 24 . The fuel tank 8 is supported on a main frame 21, and a seat 9 on which a rider sits is arranged behind the fuel tank 8. As shown in FIG. The seat 9 is supported by seat rails 24 .

<Internal combustion engine and peripheral structure>
The internal combustion engine 3 and its peripheral structure will be described with reference to FIGS. 1 to 4. FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, showing the vicinity of the passage member 11 viewed from above. 3 is a sectional view taken along line BB of FIG. 2, and FIG. 4 is a sectional view taken along line CC of FIG.

The internal combustion engine 3 is a SOHC 2-valve, single-cylinder, 4-stroke internal combustion engine, and includes a head cover 31, a cylinder head 32, a cylinder block 33, and a crankcase 34 in this order from the top. The internal combustion engine 3 is tilted forward and supported by the vehicle body frame 2, and the cylinder axis L1 is tilted forward with respect to the vertical direction. A line L1 indicates the cylinder axis and indicates the central axis direction of the cylinder bore 33a of the cylinder block 33. As shown in FIG. A piston 33b in the cylinder bore 33a reciprocates in the direction of the cylinder axis L1 to rotate the crankshaft 34a. The crankshaft 34a is oriented in the left-right direction (vehicle width direction).

The cylinder head 32 includes a combustion chamber 320 and an intake port 321 and an exhaust port 322 communicating with the combustion chamber 320 . The intake port 321 opens to the rear side of the cylinder head 32 and the exhaust port 322 opens to the front side of the cylinder head 32 . The intake port 321 and the exhaust port 322 are opened and closed by an intake valve and an exhaust valve (both not shown) driven by a valve mechanism 333 .

The exhaust structure 15 of the internal combustion engine 3 includes an exhaust pipe 15 a connected to the cylinder head 32 . The exhaust pipe 15a forms an exhaust passage that communicates with the exhaust port 322 of the cylinder head 32, and combustion gas is discharged through the exhaust pipe 15a.

The intake structure 10 of the internal combustion engine 3 includes a passage member 11 connected to the cylinder head 32, a throttle 12 connected to the passage member 11, and a connecting pipe 13 connecting the throttle 12 and the air cleaner box 14. An air cleaner is arranged in the air cleaner box 14 . The connection pipe 13 extends from the air cleaner box 14 to the front side of the vehicle 1 through the side of the main frame 21 and is bent to the right side of the vehicle 1 (see FIG. 2). The air purified by the air cleaner is introduced into the intake port 321 of the cylinder head 32 through each intake passage of the connection pipe 13 , the throttle 12 and the passage member 11 . The cylinder head 32 has a connecting surface 32a to which the passage member 11 is connected via a gasket, and the intake port 321 opens to the connecting surface 32a.

A mounting boss 113 is provided on the passage member 11 and an injector 16 is mounted on the mounting boss 113 . The injector 16 injects fuel contained in the fuel tank 8 into the intake port 321 . The mounting boss 113 has a hole 113a into which the tip side of the injector 16 is inserted. A line L2 in FIG. 3 indicates the axial direction of the hole 113a and indicates the fuel injection direction of the injector 16. As shown in FIG.

In the case of this embodiment, the intake port 321 includes an upper passage 321a and a lower passage 321b that are vertically partitioned, and a confluence passage 321c. The upper passage 321a and the lower passage 321b open to the connecting surface 32a on the upstream side thereof and merge on the downstream side thereof to form a confluence passage 321c. The confluence passage 321 c communicates with the combustion chamber 320 . By vertically partitioning the passage of the intake port 321 , tumble can be generated in the combustion chamber 320 .

The fuel injection port of the injector 16 faces the upper passage 321a, and the line L2 passes through the junction passage 321c. The fuel injected from the injector 16 is more likely to flow toward the confluence passage 321c, and the air passing through the upper passage 321a and the lower passage 321b can be mixed with the fuel.

<Passage material>
The structure of the passage member 11 will be described with reference to FIGS. 5 to 8. FIG. FIG. 5 is a plan view of the passage member 11, more precisely, a view from the side of the head cover 31 in the direction of the line L1. FIG. 6 is a view of the passage member 11 viewed from the side of the connection surface 111a where the passage member 11 is connected to the cylinder head 32 via the gasket. FIG. 7 is a view of the passage member 11 viewed from the side of the connecting surface 112a connected to the throttle 12. As shown in FIG. FIG. 8 is a cross-sectional view taken along line DD of FIG.

The passage member 11 integrally includes a cylindrical pipe portion 110 , a flange portion 111 at one end of the pipe portion 110 , and a flange portion 112 at the other end of the pipe portion 110 . An end surface of the flange portion 111 is a connection surface 111a that is connected to the connection surface 32a of the cylinder head 32 via a gasket. An end surface of the flange portion 112 is a connection surface 112 a that is connected to the throttle 12 .

The passage member 11 includes an upper intake passage 11a and a lower intake passage 11b formed from the connection surface 112a to the connection surface 111a. The upper intake passage 11a and the lower intake passage 11b are separated by a wall portion 11c. The upper intake passage 11a and the lower intake passage 11b are separated from each other at the connection surface 111a and are opened. It communicates with the lower passage 321b. On the other hand, the upper intake passage 11a and the lower intake passage 11b merge on the upstream side and form one opening at the connecting surface 112a to communicate with the throttle 12. As shown in FIG.

The intake structure having a plurality of passages (passages 11a and 321a and passages 11b and 321b) according to the present embodiment does not have individual control valves, and is a structure in which intake is controlled by a common throttle 12. .

The pipe portion 110 extends linearly in a direction perpendicular to the line L1 on the flange portion 111 side, and is bent leftward in plan view at a bent portion 110a on the flange portion 112 side. By bending the pipe portion 110, the length of the vehicle 1 in the front-rear direction is shortened, and the passage lengths of the upper intake passage 11a and the lower intake passage 11b are secured longer, or the layout of peripheral parts is improved. improves. 5 and 8, the arrow BD indicates the bending direction of the bent portion 110a, with OUT indicating the outside and IN indicating the inside. The inner portion 110b and the outer portion 110c of the peripheral surface of the tube portion 110 correspond to the inner portion and the outer portion in the inward-outward direction BD. In this embodiment, since the bent portion 110a is bent leftward in the vehicle width direction, the inner side 110b of the bent portion 110a is positioned on the left side and the outer side 110c is positioned on the right side in the vehicle width direction of the vehicle 1 .

The mounting boss 113 is formed integrally with the flange portion 111, partially extends to the pipe portion 110, and protrudes outward from the flange portion 111 and the pipe portion 110 (in the direction of line L2). The mounting boss 113 is a tubular portion forming a hole 113a, and the hole 113a communicates with the upper intake passage 11a. The cylindrical mounting boss 113 is arranged so close to the connection surface 111a that the outer peripheral edge of the mounting boss 113 contacts the connection surface 111a. As a result, the injector 16 can be arranged closer to the combustion chamber 320 and the fuel can be injected closer to the combustion chamber 320 . A line L2, which is the axial direction of the hole 113a, passes through a position offset from the center line CT of the upper intake passage 11a, and is directed to a deeper position of the intake port 321 (that is, the confluence portion 321c). , holes 113a are formed. This also contributes to injecting fuel from the injector 16 to a position closer to the combustion chamber 320 .

Fastening portions 111b (bolt holes in this embodiment) are formed on the flange portion 111 on opposite sides of the upper intake passage 11a, and are fixed to the cylinder head 32 by the fastening portions 111b.

Mainly referring to FIGS. 5 and 6, the position of the mounting boss 113 in the radial direction of the upper intake passage 11a and the projecting direction (line L2 direction) will be described.

The mounting boss 113 is arranged at a position radially offset from the center line CT. Also, the projecting direction (direction of line L2) is a direction intersecting with line L1'. A line L1' passes through the center line CT and is parallel to the line L1, and indicates the direction of the cylinder axis. In the conventional example, the mounting boss of the injector is arranged on the line L1' in FIG. As in the present embodiment, the mounting boss 113 is radially offset with respect to the center line CT, and the projecting direction intersects the cylinder axial direction. can be lowered. For reference, FIG. 6 shows the expected projecting height H' when a similar mounting boss is formed on line CL. The protrusion height H' has a larger protrusion amount than the protrusion height H.

By suppressing the amount of protrusion of the mounting boss 113 with the configuration of this embodiment, the mounting boss 113 can be arranged at a position close to the cylinder head 32 while avoiding interference with the head cover 31 and the cylinder head 32 . In other words, the injector 16 can be arranged closer to the combustion chamber 320 of the cylinder head 32 and the fuel can be injected closer to the combustion chamber 320 .

In terms of suppressing the amount of protrusion of the mounting boss 113, it does not matter which direction the mounting boss 113 is offset from the center line CT. However, in this embodiment, the passage member 11 is bent at the bent portion 110a. As shown in FIGS. 5 and 8, of the space around the passage member 11, the space S2 adjacent to the inner side 110b of the bent portion 110a on the left side is narrower than the space S1 adjacent to the outer side 110c. Therefore, in this embodiment, the mounting boss 113 is arranged at a position biased toward the outside (OUT) rather than the inside (IN) in the inside and outside directions of bending of the bending portion 110a. As a result, the injector 16 attached to the mounting boss 113 is positioned on the side of the wider space S1, and restrictions on placement of other components around the mounting boss 113 can be reduced.

<Structure around passage member>
The structure around the passage member 11 will be described with reference to FIGS. 2 to 4, 9 and 10. FIG. 9 is a cross-sectional view along line EE of FIG. 4, and FIG. 10 is a cross-sectional view along line FF of FIG. The throttle 12 of this embodiment is arranged near the center of the vehicle 1 in the vehicle width direction. As a result, the protrusion of the throttle 12 in the vehicle width direction can be suppressed.

The throttle 12 of this embodiment includes a valve body portion 120 and a drum portion 121 . 9 and 10 show the drum section 121 in a transparent view through the case portion thereof. The drum 121 portion includes a drum 121a that is connected to the throttle grip 5a via a wire (not shown) and that rotates when the throttle grip 5a is operated. The valve body portion 120 is provided coaxially with the drum 121a, and is provided with a butterfly-type throttle valve 120a that controls the amount of intake air by rotating the drum 121a.

The drum portion 121 is disposed laterally of the passage member 11, and in particular, adjacent to the inner side 110b of the bent portion 110a rather than the outer side 110c. That is, the drum portion 121 is arranged inside (IN) the passage member 11 in the inside and outside directions of the bending of the bending portion 110a, and is arranged in the region S2 in FIGS. The area S2, which is relatively narrower than the area S1, can be used as a space for arranging the drum section 121. As shown in FIG.

The injector 16 is provided with a connection portion 16a (see FIG. 2) to which a fuel pipe (not shown) is connected. The injector 16 as a whole is arranged on the right side of the center of the vehicle 1 in the vehicle width direction, while the connecting portion 16 a faces toward the center of the vehicle 1 in the vehicle width direction. Projection of the fuel pipe in the vehicle width direction can be suppressed.

Referring to FIG. 9, in order to avoid the injector 16, the head cover 31 has a avoiding portion 31a, and the cylinder head 32 has a avoiding portion 32b. Both the avoiding portion 31a and the avoiding portion 32b are concave portions recessed in the direction parallel to the center line CT and on the side opposite to the passage member 11 (that is, the front side of the vehicle 1).

The avoiding portion 31a is formed in a portion of the lower portion of the head cover 31 that is adjacent to the connection surface 32a and overlaps with the cylinder head 32. In particular, the peripheral portion of the head cover 31 that contacts the deck surface of the cylinder head 32. It is formed in a certain range including the lower surface. The avoiding portion 32b is formed so as to vertically overlap the same portion as the avoiding portion 31a around the deck surface of the cylinder head 32, and is formed above the connecting surface 32a.

Although a configuration without such avoiding portions 31a and 32b can be adopted, the injector 16 can be arranged at a position closer to the combustion chamber 320 by forming the avoiding portions 31a and 32b.

<Other embodiments>
In the above embodiment, the intake port 321 has two intake passages 321a and 321b, and the passage member 11 has two intake passages 11a and 11b correspondingly. may be a configuration having

Although the embodiments of the invention have been described above, the invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

Claims (8)

a passage member (11) connected between a cylinder head (32) provided with a head cover (31) and a throttle (12) to form an intake passage (11a);
a mounting boss (113) provided in the passage member (11) to which an injector (16) for injecting fuel is mounted;
An intake structure (10) for an internal combustion engine (3) mounted on a straddle-type vehicle (1), comprising:
The passage member (11) is
a bending portion (110a) that bends the passage direction of the intake passage (11a) in the vehicle width direction of the straddle-type vehicle (1);
a flange portion (111) having a connection surface (111a) connected to the cylinder head (32),
The mounting boss (113) is
formed integrally with the flange portion (111) at a position biased outward (OUT) from the inner side (IN) in the inward-outward direction (BD) of the bend of the bent portion (110a), and
When the passage member (11) is viewed from the connecting surface (111a) side, the passage member (11) protrudes in a direction (L2) intersecting with the cylinder axial direction (L1'),
The cylinder head (32) is
a connection surface (32a) to which the connection surface (111a) of the passage member (11) is connected;
a first avoidance portion (32b) formed adjacent to the connection surface (32a) and avoiding the injector (16);
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to claim 1,
The mounting boss (113) has a hole (113a) into which the injector (16) is inserted and defines a fuel injection direction (L2) of the injector,
The axial direction (L2) of the hole (113a) is offset from the centerline (CT) of the intake passage (11a),
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to claim 1 or claim 2,
The throttle (12) is attached to the upstream end (112) of the passage member (11),
The drum portion (121) of the throttle (12) is located inside (IN) of the bending of the bending portion (110a) in the lateral direction (BD),
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to claim 2,
The passage member (11) is
a first intake passage (11a), which is the intake passage;
forming a second intake passage (11b) separate from the first intake passage;
The intake port (321) of the cylinder head (32) is
a first passageway (321a) communicating with the first intake passageway (11a);
a second passageway (321b) communicating with the second intake passageway (11b);
a confluence passageway (321c) in which the first passageway (321a) and the second passageway (321b) merge on the downstream side,
The axial direction (L2) of the hole (113a) passes through the joint passage (321c),
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to any one of claims 1 to 4,
The head cover (31) is adjacent to the connection surface (32a) of the cylinder head (32) and overlaps with the cylinder head (32) as a second avoiding portion that avoids the injector (16). including (31a)
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to any one of claims 1 to 5 ,
The injector (16) is provided with a connection portion (16a) to which a fuel pipe is connected,
The connecting portion (16a) faces inward (IN) in the medial-lateral direction (BD),
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to claim 2,
The entrance of the hole (113a) is located outside (OUT) of the center line (CT) in the medial-lateral direction (BD),
An intake structure for an internal combustion engine, characterized by: An intake structure for an internal combustion engine according to claim 1,
The mounting boss (113) is formed within the width of the flange portion (111) in the passage direction,
An intake structure for an internal combustion engine, characterized by:

Images