JP3012023B2 - Engine intake control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device suitable for, for example, a four-valve engine having two intake valves and two exhaust valves, and in particular, by narrowing a cross-sectional area of an intake passage at low speed rotation or low load. Also, the present invention relates to an improvement in the shape, structure, and arrangement of an intake control valve capable of generating a so-called vertical swirl by increasing the flow velocity even when the amount of intake air is small, thereby improving the fuel consumption rate (hereinafter referred to as fuel efficiency).

[0002]

2. Description of the Related Art In order to improve the fuel efficiency of an engine, a vertical swirl is generated in a combustion chamber by increasing the flow velocity even when the intake air amount is small, such as during low-speed rotation or low-load operation. It is effective to stabilize combustion. Conventionally, as an intake control device capable of generating such a vertical swirl, for example, as disclosed in Japanese Patent Publication No. 59-5767, a control plate is arranged so as to be able to undulate near an intake valve opening of an intake passage to rotate at a low speed. Alternatively, there is a type in which the control plate is raised during a low-load operation to reduce the area of the intake passage.

[0003]

However, in the above-described conventional intake control device, a space is created downstream of the control plate at the time of low-speed rotation or the like, and the intake flow is caught in the space, causing turbulence. There is a problem that swirl is difficult to obtain. Also, due to the structure of raising and lowering the control plate, the control plate is relatively long, which requires a large arrangement space and a problem that the cylinder head portion becomes large.In addition, even when the control plate is fully opened, the control plate remains in the intake passage. There is also a problem that this remains, which becomes intake resistance at the time of high-speed rotation or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to reliably obtain a vertical swirl by suppressing turbulence of an intake air flow, and to reduce a layout space.
It is another object of the present invention to provide an intake control device for an engine that can avoid the problem of an increase in intake resistance at the time of high-speed rotation or the like.

[0005]

According to the present invention, a spark plug is disposed substantially at the center of a combustion chamber, an intake valve is disposed so as to extend substantially in the cylinder axis direction, and the intake valve opening is formed in a cylinder head by an intake passage. In the intake control device for an engine led to an outer wall, the intake passage includes a bent portion that bends in an arc shape from the opening toward the cylinder head outer wall side and a linear portion that extends substantially linearly from the bent portion. One intake control valve, which is formed by forming an intake recess in a rod having a circular cross section, is disposed in the bent portion of the wall surface on the side of the passage and the cylinder block in parallel with the cam shaft and rotatably. When the intake control valve is rotated to the closed position, the intake concave portion narrows the passage sectional area, and when rotated to the fully open position, the inner surface of the intake concave portion forms a substantially continuous surface with the wall surface of the intake passage. It is characterized by:

[0006]

According to the intake control apparatus of the present invention, when the amount of intake air is small, such as during low-speed rotation, the intake control valve pivots to the closed position so that the intake concave portion bottoms the intake passage area. By restricting from the wall surface side, the intake air is increased in flow velocity and flows along the ceiling wall of the intake passage, and is blown directionally near the center of the combustion chamber, so that vertical swirl is reliably generated. When the amount of intake air is large, such as during high-speed rotation, the intake control valve is rotated to the open position, and the inner surface of the intake concave portion is substantially flush with the wall surface of the intake passage. The intake air flows through the entire intake passage without resistance and is blown into the combustion chamber. As described above, in the present invention, since the intake control valve is formed in a rod shape having a circular cross section, it is possible to prevent the generation of a space downstream of the control valve to prevent the intake flow from being entrained, and to connect the intake control valve to the intake passage. Since the control valve can be disposed near the intake valve opening because the control valve is disposed at the bent portion of the wall surface on the mating side with the cylinder block, it is possible to give directionality to the intake air flowing into the combustion chamber, and as a result, Vertical swirl can be generated reliably. In addition, since the intake control valve is a circular rod, it can be disposed near the intake valve opening as described above, and the arrangement space can be reduced. As a result, the cylinder head can be made compact. Furthermore, since the circular concave body is formed with an intake concave portion that forms a continuous surface with the wall surface of the intake passage when opened, the provision of the intake control valve can prevent an increase in intake resistance during high-speed rotation or the like.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 8 are views for explaining an intake control device for a four-valve engine according to one embodiment of the present invention.

In the figure, 1 is a water-cooled 4-cycle parallel 4
It is a four-cylinder cylinder engine,
The cylinder block 3 and the cylinder head 4 are stacked on the upper side in a forwardly inclined state, connected by a head bolt 6, and a head cover 5 is put on the upper mating surface of the cylinder head 4. A piston 7 is slidably inserted into each of the four cylinder bores 3a formed in the cylinder block 3, and each piston 7 is connected to a crankshaft (not shown) by a connecting rod 8.

A lower surface 4a of the cylinder head 4 on the side of the cylinder block 3 has a combustion recess 4b forming a combustion chamber.
Is recessed. An ignition plug 9 is screwed into the center of the combustion recess 4b, and two intake valve openings 4c and two exhaust valve openings 4d are opened around the plug 9. The valve plate 1 of the exhaust valve 10 is provided in each exhaust valve opening 4d.
In the intake valve opening 4c, a valve plate 11a of the intake valve 11 is disposed so as to open and close the openings 4d and 4c, respectively. The valve shafts 10b and 11b of the exhaust and intake valves 10 and 11 extend obliquely upward in the cylinder axis direction so as to form a predetermined included angle when viewed in the cam axis direction. 13 are mounted. Exhaust and intake camshafts 1 for driving the lifters 12 and 13 are provided on the respective lifters 12 and 13.
4 and 15 are arranged in a direction perpendicular to the cylinder axis and parallel to each other. A cam chain (not shown) connecting the exhaust / intake camshafts 14, 15 and the crankshaft is provided with a chain chamber 4 formed in the center of the four cylinder bores 3a.
e.

The two exhaust valve openings 4d are led out to the front wall 4f side of the cylinder head 4 through a bifurcated exhaust passage 16, and an exhaust pipe (not shown) is formed in the wall opening 16a of the exhaust passage 16. Is connected. The two intake valve openings 4c are led out to the rear wall 4g side of the cylinder head 4 through a forked intake passage 17. The intake passage 17 extends in a direction substantially perpendicular to the camshaft 15 when viewed in the cylinder axis direction, and after being bent in an arc shape from the intake valve opening 4c to the cylinder rear wall 4g side when viewed in the camshaft direction. , And extend substantially linearly. A carburetor 19 is connected to a wall opening 17 a of the intake passage 17 via a cab joint 18. The carburetor 19 is of an automatic variable venturi type having a butterfly type throttle valve 19a which opens and closes by a throttle operation, and a piston valve 19b which automatically opens and closes by negative pressure of the intake air of the engine. An air cleaner 20 is connected to a suction port 19 c of the vaporizer 19.

A valve hole 17c is formed in the bent portion 17b of the intake passage 17 which is bent in the arc shape in the cam shaft direction. The valve hole 17c has an axis near the bottom wall surface 17d of the intake passage 17 and the intake valve shaft 11b.
And between the head bolt 6 and the bent portion 17b.
7, 17 are communicated. An intake control valve 2 for changing the passage sectional area of the intake passage 17 is provided in the valve hole 17c.
1 is rotatably disposed. The control valve 21 is provided as a pair of left and right sides with the cam chain interposed therebetween, and is formed by cutting out four intake recesses 21a in a round bar. As shown in FIG. 5, the intake recess 21a forms a part of the bottom wall surface 17d and the side wall surface 17e of the intake passage 17 when fully opened. The downstream end of the intake recess 21a is formed in an arc shape as shown in FIG.
Thereby, it is continuous with the bent portion 17b. Further, as shown in FIG. 4, the intake recess 21a narrows the bottom wall 17d side portion of the intake passage 17 and opens only the top wall 17f side when fully closed. Although not shown, the intake control valve 2
1 is opened and closed by a throttle operation. In this case, the intake control valve 21 is maintained in a fully closed state until the throttle opening becomes a predetermined low opening, and is opened as the throttle opening further increases, and becomes fully open at a predetermined high opening or more. .

Each intake passage 1 of the cylinder head 4
The injection hole 22a is formed in the lower part of the opening 7 so as to open to a portion of the valve hole 17c facing each of the intake recesses 21a. Each of the injection holes 22a is connected to a common pipe 22c extending in the cam axis direction by a connection pipe 22b, and the common pipe 22c is connected to a secondary side of the air cleaner 20 by an introduction hose 22d. An on-off valve 23 is provided in the middle of the introduction hose 22d. The on-off valve 23 has a valve rod 23b in a case 23a.
Are arranged so as to be biased in the closing direction, and are opened when the negative pressure of the intake control valve 21 portion of the intake passage 17 becomes a predetermined value or more.

Next, the operation and effect of this embodiment will be described. When the intake air amount is small as in the case of low-speed rotation of the engine or low-load operation, as shown in FIGS. 1 and 4, the intake control valve 21 is rotated to the fully closed position. Therefore, the intake passage 17 is narrowed from the bottom wall surface 17d side, and the top wall surface 17f
Only the side will be open. As a result, the flow velocity of the intake air is increased in the throttle section, and the top wall surface 17 of the intake passage 17 is
It flows along f and is blown directionally near the center of the combustion chamber, generating a vertical swirl as shown by the arrow in FIG. In this case, since the intake control valve 21 is formed in a columnar shape and is disposed at the bent portion 17b, the control valve 21 can be brought close to the intake valve opening 4, and at the downstream side of the control valve 21. Since the entrainment of the intake air flow can be prevented without generating a space, the directionality can be further ensured. As a result, even if the air-fuel ratio is made lean, combustion can be stabilized, and fuel efficiency can be improved.

When the intake air amount is large as in the case of high-speed rotation of the engine or high-load operation, as shown in FIG.
The intake control valve 21 is rotated to the fully open position, whereby the intake recess 21a forms a continuous surface with the intake passage 17, and the intake control valve 21 does not have intake resistance. In addition, intake recess 2
Since the tip of 1a has an arc shape, the intake resistance can be reduced even when the control valve 21 is fully closed.

Further, since the intake control valve 21 is formed in a rod shape, the intake control valve 21 can be disposed close to the intake valve opening and the arrangement space can be reduced as described above. Can be placed between 6,
Compact around the cylinder head. Here, in the engine of the present embodiment, the intake valve 11 is slanted outward with respect to the cylinder axis. Therefore, if the intake control valve is disposed on the top wall 17f side of the intake passage 17, interference with the valve shaft 11b will occur. In order to avoid this, the control valve is disposed outside, and the cylinder head is increased in size. However, in this embodiment, since the control valve is disposed on the bottom wall 17d side, an arrangement space can be easily secured, and the problem of the enlargement described above is caused. Can be avoided. Further, as described above, the air intake control valve 2 can be disposed between the head bolt 6 and the valve shaft 11b.
1 can be extended without difficulty to the adjacent intake passage,
One control valve can control intake to two cylinders. Accordingly, it is possible to easily cope with a plurality of cylinder engines without complicating the structure of the intake control device. It should be noted that the intake control valve 21 can of course be set to a length corresponding to all the intake passages of the four cylinders.

The intake control valve 21 is connected to the intake recess 21.
a is disposed so as to face the upstream side, so that no space is generated on the downstream side of the control valve, that is, on the intake valve opening side as described above, and the accumulation of carbon due to blowback from the combustion chamber can be avoided. There is no hindrance to the operation of. Furthermore, since the injection hole 22a is opened in the valve hole 17c, when the control valve 21 is closed and the negative pressure in the vicinity of the valve hole 17c increases, air is injected toward the intake recess 21a, It is possible to avoid accumulation of fuel in this portion.

FIG. 9 shows a modified example of the injection hole portion for injecting air into the valve hole in which the intake control valve is inserted. In the drawing, the same reference numerals indicate the same or corresponding portions. In this modification, the carburetor 1 is provided with an injection hole 22a opened in the valve hole 17c through an introduction hole 18c formed in the cab joint 18.
9 is opened in the vicinity of the discharge port of FIG.
The same effect as in the case of is obtained.

FIGS. 10 to 12 show modifications of the intake concave portion of the intake control valve. In the drawings, the same reference numerals as those in FIGS. 3 to 5 denote the same or corresponding parts. In this modification, a pair of intake recesses 21a 'corresponding to each cylinder are formed obliquely so that the central portion is lowered, so that when the intake control valve 21 is fully closed as shown in FIG. Portions of the intake passage open larger than at the center, so that more intake air flows into the center of the combustion chamber.

FIG. 13 shows an embodiment in which the present invention is applied to a fuel injection type engine. In the drawing, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the present embodiment, a fuel injection valve 26 is mounted on a top wall portion of the intake passage 17, and the injection nozzle of the fuel injection valve 26 has an upper edge of the intake control valve 21 through an injection hole 26 a, that is, the smallest intake passage area. The portion is directed to a portion extending from the portion to the back surface of the valve plate 11a of the intake valve 11. Here, the injection timing from the fuel injection valve 26 at the time of low-speed rotation or the like is set during the intake stroke. That is, the intake valve 11
Is opened, the intake air is blown, and the fuel is injected at the time when the vertical swirl occurs. In addition, the intake passage 1
A throttle body 24 is connected to the rear wall opening 17a of the actuator 7 via a joint 18, and a drive arm 24b of a throttle valve 24a and a drive arm 21b of an intake control valve 21 disposed in the body 24 are driven. It is connected to the throttle grip 25 via cables 25b, 25a and a connecting member 25c. Here, the connection member 25c rotates the throttle valve 24a without delay with respect to the rotation operation of the throttle grip 25,
In addition, it is for rotating the intake control valve 21 with a slight delay. In this embodiment, the fuel injection valve 2
The fuel injected from 6 also strikes the intake control valve 21, so that the control valve 21 can be cooled. In addition, since the fuel is injected during the intake process, stratification is possible, and combustion at a leaner air-fuel ratio is possible.

[0020]

As described above, according to the intake control apparatus for an engine according to the present invention, the intake control valve is a rod having a circular cross section, so that it is possible to avoid the generation of a space downstream of the control valve. Entrapment of the intake air flow can be prevented, and the intake control valve is arranged at the bent portion of the intake passage, so that the control valve can be arranged near the intake valve opening, so that a strong direction is given to the intake air flowing into the combustion chamber. As a result, the vertical swirl is reliably generated, the lean air-fuel ratio combustion at the time of low-speed rotation or the like can be stabilized, and the fuel consumption can be improved. In addition, since the intake control valve is a circular rod, it can be disposed near the intake valve opening as described above, and the arrangement space can be reduced. As a result, there is an effect that the cylinder head portion can be made compact. Since the intake recess is formed in the rod body and forms a continuous surface with the wall surface of the intake passage when fully closed, there is also an effect of avoiding an increase in intake resistance during high-speed rotation and the like.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing an intake control device for an engine according to one embodiment of the present invention.

FIG. 2 is a bottom view of a cylinder head of the engine of the embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a sectional view showing a high-speed operation state of FIG.

FIG. 6 is a front view of the intake control valve of the embodiment.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is an enlarged view of an intake concave portion of the intake control valve.

FIG. 9 is a cross-sectional view of a modified example of the air injection hole portion of the embodiment.

FIG. 10 is a cross-sectional plan view of a modified example of the intake control valve of the embodiment.

FIG. 11 is a sectional front view of the intake control valve of the modified example shown in FIG. 10;

FIG. 12 is a sectional front view of an intake control valve according to a modification shown in FIG. 11;

FIG. 13 is a sectional side view showing an embodiment when the present invention is applied to a fuel injection engine.

[Explanation of symbols]

 Reference Signs List 1 engine 4 cylinder block 4a mating surface 4b combustion recess (combustion chamber) 4c intake valve opening 4g cylinder head outer wall 9 spark plug 11 intake valve 11b intake valve shaft 15 camshaft 17 intake passage 21 intake control valve 21a intake recess

Claims (1)

(57) [Claims] 1. An ignition plug is disposed substantially at the center of a combustion chamber.
An intake valve is disposed so as to extend substantially in the axial direction of the cylinder, and the opening for the intake valve is led to an outer wall of a cylinder head through an intake passage.
In the gin intake control device, the intake passage is
From the cylinder head to the outer wall side of the cylinder head
A linear part extending substantially linearly from the bent part; and
And the wall surface on the mating side of the intake passage with the cylinder block
In the bent portion, one intake control valve formed by forming an intake concave portion in a rod having a circular cross section is disposed so as to be rotatable in parallel with the camshaft, and pivots the intake control valve to the closed position. An intake control device for an engine, wherein the intake recess portion narrows a passage cross-sectional area when the intake recess portion is turned, and an inner surface of the intake recess portion forms a substantially continuous surface with a wall surface of the intake passage when the intake recess portion is rotated to a fully open position.