JP3320775B2 - 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 system for an engine in which an intake passage area is controlled by an intake control valve. The present invention relates to an improvement in the structure of an intake control valve and an intake passage capable of improving a fuel efficiency in a high speed / low load operation range.

[0002]

2. Description of the Related Art In order to improve the fuel efficiency of an engine, it is effective to stabilize combustion at a lean air-fuel ratio by generating a vertical swirl in a combustion chamber by increasing the flow velocity even in an operation range where the amount of intake air is small. It is known that Conventionally, as an intake control device capable of generating such a vertical swirl, as described in Japanese Patent Publication No. 59-5767, for example, a control plate is arranged so as to be able to undulate near an intake valve opening of an intake passage, and a low-speed rotation is performed. Alternatively, there is one in which the control plate is raised during a low-load operation to narrow the intake passage area.

[0003]

However, in the above-described conventional intake control device, a space is generated 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.
Further, since the control plate remains in the intake passage even at the time of full opening, there is also a problem that this becomes intake resistance at the time of high-speed rotation or the like.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to prevent the turbulence of the intake air flow and to surely generate the vertical swirl, and to increase the intake resistance at the time of high speed rotation or the like. It is an object of the present invention to provide an intake control device for an engine that can also avoid problems.

[0005]

According to a first aspect of the present invention, there is provided an intake control valve which narrows a bottom wall portion of an intake passage when the amount of intake air is low, thereby biasing the intake air toward the top wall of the intake passage. The bottom wall is movably disposed between a fully closed position protruding into the intake passage and a fully open position immersed in the bottom wall, and a portion of the intake passage downstream of the intake control valve is a top wall side passage. And a partition plate for partitioning into a bottom wall side passage, a cross-sectional area at the downstream end of the top wall side passage is set to be smaller than a cross-sectional area at the upstream end, and a portion near the intake valve opening of the partition plate is Are formed so as to be close to and along the valve stem of the intake valve.

According to a second aspect of the present invention, the cross-sectional shape of the intake passage is substantially inverted triangle, and the upstream end of the partition plate is located near the base of the triangle and substantially parallel to the base. It is characterized by.

[0007]

According to the intake control apparatus for an engine of the present invention, when the amount of intake air is small, the intake control valve narrows the bottom wall side portion of the intake passage, and the partition plate covers the downstream side of the intake control valve. Since it is divided into a wall side passage and a bottom wall side passage,
The inhaled air flows at a high flow velocity unbalanced to the ceiling wall side.
Moreover, since the partition plate narrows the downstream portion of the top wall side passage, the flow velocity further increases from this point. As a result, the intake air flowing into the cylinder is given a vertical direction flowing in the cylinder axial direction. As a result, a vertical swirl is generated, and lean combustion is performed stably.

On the other hand, when the amount of intake air is high, the intake control valve pivots to the fully closed position where it is immersed in the bottom wall, so that the intake control valve does not remain in the intake passage and an increase in intake resistance is avoided. it can. In addition, since the portion near the opening of the intake valve of the partition plate is formed so as to be close to and along the valve stem of the intake valve, it is possible to suppress an increase in intake resistance at a high intake air amount from this point.

According to the second aspect of the present invention, since the cross-sectional shape of the intake passage is substantially inverted triangle, the area on the top wall side is larger when the passage area is the same. The upstream end of the partition plate is located near the bottom of the triangle, that is, at the portion having the largest cross-sectional area. The amount of increase in the passage area when the intake control valve is rotated from the fully closed position by a fixed angle in the opening direction can be increased as compared with the conventional structure having the intake passage having a circular cross section. The area of the intake passage can be sharply increased at the time of acceleration or the like, and as a result, the problem of supply delay of the air amount due to the arrangement of the intake control valve and the partition plate can be avoided.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 5 are views for explaining an intake control device for an engine according to a first embodiment of the present invention. FIG. 1 is a sectional side view of an engine provided with the embodiment device.
Is a cross-sectional side view of the main part around the intake control valve, and FIG.
FIG. 4 is a perspective view around the partition plate, and FIG. 5 is a sectional view taken along the line VV in FIG.

In FIG. 1, reference numeral 1 denotes a water-cooled four-cycle four-valve engine, in which a cylinder block 3 and a cylinder head 4 are stacked on a crankcase 2 and fastened with head bolts. It has a structure in which the head cover 5 is mounted on the surface 4i. A piston 7 is slidably inserted into a cylinder bore 3a formed in the cylinder block 3, and the piston 7 is connected to a crankshaft (not shown) by a connecting rod 8.

A combustion recess 4b constituting a combustion chamber is formed in the cylinder block 4 mating surface 4a of the cylinder head 4. The combustion recess 4b has two intake valve openings 4c and two exhaust valve openings 4d. A valve head 10a of the exhaust valve 10 is provided at each exhaust valve opening 4d.
In the intake valve opening 4c, a valve head 11a of the intake valve 11 is arranged so that each opening can be opened and closed. The valve stems 10b, 11b of the exhaust and intake valves 10, 11 extend obliquely upward so as to form a predetermined angle when viewed in the cam axis direction, and have exhaust and intake lifters 12, 13 at their upper ends.
Are attached. The lifters 12, 13
On the top, the exhaust and intake camshafts 14 and 1 that press and drive this
5 are arranged in a direction perpendicular to the cylinder axis and parallel to each other. In addition, 9 is a spark plug.

The two exhaust valve openings 4d, 4d are led out to the front wall 4f side of the cylinder head 4 through a bifurcated exhaust passage 16, and the two intake valve openings 4c, 4c are bifurcated intake passages. 17, the rear wall 4g of the cylinder head 4
Has been derived to the side. The intake passage 17 has a substantially inverted triangular cross-sectional shape (the bottom side is located on the top wall 17b side) (see FIG. 5). Therefore, the passage area is smaller than that of the intake passage having a circular cross section. It is biased by the top wall 17b side.
The intake passage 17 is viewed in the camshaft direction (FIG. 1,
2), the cylinder rear wall 4g from the intake valve opening 4c.
After being bent in an arc shape to the side, it extends substantially linearly. A wall opening 17a where the intake passages 17 merge into one.
Is connected to a carburetor 19 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.

A valve hole 17c is formed in a bent portion of each of the intake passages 17 near the opening of the intake valve in the direction of the cam shaft. The axis of the valve hole 17c is located near the surface of the bottom wall 17d of the intake passage 17, and the inside of the intake passage 17 is formed in a substantially semicircular shape. 17 is communicated. In this valve hole 17c,
An intake control valve 21 for changing the passage sectional area of each intake passage 17 is rotatably inserted and disposed. The intake control valve 21 forms a valve portion 21a for opening and closing each intake passage 17 by cutting a part of a round bar so as to form a continuous surface with the lower inner surface of the intake passage 17. The fully open position where the portion 21a is immersed in the valve hole 17c and is flush with the inner surface of the intake passage, and the valve portion 21a stands almost perpendicularly from the bottom wall 17d surface and narrows the intake passage 17 to approximately 1/2. It can rotate between the closed position. In this case, the valve 21a rotates so that the outer peripheral surface of the valve 21a is located on the upstream side.

A control pulley 22a is fixed to an outer end of the intake control valve 21, and the control pulley 22a is connected to a drive pulley 22c fixed to a control motor 22b by a cable 22d. The control motor 22b has an E
The rotation is controlled by a CU (control device) 23.
The ECU 23 receives the throttle valve opening signal a from the throttle opening sensor 24 and the engine speed signal b from the engine speed sensor 25, and sets the intake control valve 21 in the low-medium-speed / low-load operation range. When the intake air amount is small, the control signal S is output to the fully closed position, and when the intake air amount is large, such as in a high-speed, high-load operation range, the control signal S is rotated to the fully opened position. I do.

A partition plate 20 is arranged downstream of the intake control valve 21 on each intake passage 17 side. The partition plate 20 has a flat upstream portion 20a, a substantially V-shaped downstream portion 20c formed continuously therefrom, and a downstream portion 20c.
And an annular holding ring 20b fixed to the downstream end of the intake valve opening 4c.
, Which is pinched and fixed by a valve seat press-fitted into the valve.

The upstream end of the upstream portion 20a is located near the bottom (top wall) of the intake passage 17 forming the substantially inverted triangle and substantially parallel to the bottom, and has the same width as the bottom. Have. The upstream end of the upstream portion 20a comes into contact with the upper edge of the valve portion 21a of the intake control valve 21 located at the fully closed position, and forms a continuous surface with the upper edge. Thus, the partition plate 20 divides a portion of the intake passage 17 downstream of the control valve 21 into a top wall passage A and a bottom wall passage B. here,
Since the partition plate 20 changes in a V-shape with a narrower angle toward the downstream side, the top wall side passage area of the intake passage 17 becomes smaller toward the downstream side. The downstream portion 20c has a V-shape, so that the valve stem 11b of the intake valve 11 is formed.
And avoid interference.

Next, the operation and effect of this embodiment will be described. In an operating range where the amount of intake air is small, such as at low / medium speed / low load, the control motor 22b rotates the intake control valve 21 to the fully closed position shown in FIGS. Then, the valve portion 21a of the intake control valve 21 narrows the bottom wall 17d side of the intake passage 17, whereby the intake air is biased toward the top wall side passage A divided by the partition plate 20 and flows while being throttled toward the downstream side, It flows into the cylinder from the intake valve opening 4c. As a result, even when the intake air amount is small, a sufficient flow velocity can be obtained and the flow can have directionality, and when viewed in the camshaft direction, a vertical swirl that flows vertically along the cylinder axis occurs (see the arrow in FIG. 1). ).

As described above, in the present embodiment, the intake control valve 21 is provided for flowing the intake air toward the top wall of the intake passage 17, and the intake passage 17 is divided into the top wall side passage A and the bottom wall side passage B. Since the partition plate 20 is provided for dividing and reducing the passage area of the top wall side passage A toward the downstream side, when the amount of intake air is small, the intake air can flow directionally in the direction along the cylinder axis direction, and the vertical swirl can be obtained. Can be generated. As a result, lean combustion can be stabilized, and the fuel efficiency can be improved.

In this embodiment, a portion of the intake passage 17 downstream of the intake control valve 21 is divided by a partition plate 20, and the upstream portion 20 a of the partition plate 20 is formed in an arc shape of the valve portion 21 a of the intake control valve 21. Because it forms a substantially continuous surface with the outer peripheral surface of
An increase in intake resistance can be avoided, and no vortex is generated on the downstream side of the intake control valve 21, so that swirl can be more reliably generated from this point. Although a concave portion is formed on the downstream side of the valve portion 21a, since the concave portion is closed by the partition plate 20, it is possible to suppress a problem that fuel is accumulated in the concave portion.

The intake control valve 21 is controlled to a halfway opening position or a fully closed position depending on the amount of intake air. In such a state other than the fully open position, the partition plate 20 functions as a rectifying plate. Will be fulfilled. Also, this partition plate 20
Also functions as a stopper that regulates the fully open position of the intake control valve 21.

Further, in this embodiment, the intake passage 17 is formed in an inverted triangular cross section, and the upstream end of the partition plate 20 is located near the bottom of the triangle, that is, in a portion having a larger cross-sectional area. Therefore, when the intake control valve 21 is rotated in the opening direction from the fully closed state, the passage area is sharply increased at a small rotation angle as compared with the passage having a circular cross section. As a result, even when the amount of intake air needs to be rapidly increased at the time of rapid acceleration or the like, air can be introduced without delay, and the problem of response delay due to the provision of the control valve and the partition plate can be suppressed.

In the above embodiment, the intake control valve 21 is arranged near the intake valve opening 4c of the intake passage 17, but the intake control valve 21 of the present invention is, for example, as shown in FIG. It can also be provided near the external connection port 17a of the intake passage 17. In this case, the intake control valve 21 is disposed outside the head bolt 26 and the upstream portion 20
a may be extended in accordance with the arrangement position of the intake control valve 21.

Here, in order to improve the combustion by using the vertical swirl, it is necessary to more surely generate the vertical swirl by installing the partition plate or the like and to suppress the attenuation of the generated vertical swirl.

FIG. 7 shows a third embodiment in which the vertical swirl can be easily turned upside down in order to suppress the attenuation of the vertical swirl. In the drawing, the same reference numerals as those in the above embodiments indicate the same or corresponding parts. In the third embodiment, a substantially spherical concave portion 11c is formed in the lower surface of the valve head 11a of the intake valve 11.

Generally, in recent engines, the shape of the combustion chamber is made flat to increase the compression ratio. Therefore, there is a problem that the vertical swirl is easily attenuated. However, in the third embodiment, since the concave portion 11c is provided, the vertical swirl can be easily inverted upward, and the attenuation can be suppressed.

FIGS. 8 and 9 show a fourth embodiment in which the top wall of the combustion chamber is specially worked so as to prevent the flow in the vertical swirl direction from being disturbed in order to suppress the attenuation of the vertical swirl. As shown in FIG. 6, the intake and exhaust valve openings 4c, 4
The portion a between d generally protrudes into the combustion chamber, so that a step is formed. In the fourth embodiment, at least the portion between the intake and exhaust valves 11 and 10 in the step between the top wall of the combustion chamber of the cylinder head 4 and the intake valve seat 27a and the exhaust valve seat 27b that constitute the combustion recess 4b (see FIG. The hatched area a of FIG. 9 or the part a in FIG. 8) is deleted.

It should be noted that when the step is to be deleted, the steps shown in FIG.
0, as shown in the fifth embodiment in FIG.
It is also effective to delete only the side part a '. In this case, the intake air flows as indicated by the arrow in the drawing, and it is possible to avoid the intake air from hitting the valve head 10a of the exhaust valve 10.

FIGS. 12 to 14 show a sixth embodiment employing a piston shape capable of suppressing the attenuation of the vertical swirl while securing the compression ratio. In this example, the head of the piston 7 is raised into a roof shape to reduce the area of the combustion chamber to secure a compression ratio, and to provide a flat flat portion 3a at the center of the head, so that the flow of the vertical swirl is increased. As much as possible.

In each of the above embodiments, the partition plate 20 also functions as a stopper for the intake control valve 21. However, the intake control valve 21 may be stopped by the control motor 22b so as not to contact the partition plate 20. it can. In this case, the intake control valve 21 can be prevented from rebounding from the partition plate 20, and the accuracy of the opening angle can be improved.

[0031]

As described above, according to the intake control apparatus for the engine according to the first aspect of the present invention, the intake control valve for narrowing the bottom wall portion of the intake passage when the intake air amount is low is provided, and the intake passage of the intake passage is provided. The control valve downstream portion is divided into a top wall side passage and a bottom wall side passage, and a partition plate that narrows the top wall side passage toward the downstream side is provided. It can give the directionality of flowing vertically in the axial direction, and as a result, it has the effect of reliably generating vertical swirl and stabilizing lean burn, improving the fuel efficiency, and in the operating range where the intake air amount is large. Since the intake control valve does not remain in the intake passage, and the portion of the partition plate near the opening of the intake valve is formed close to and along the valve stem of the intake valve, an increase in intake resistance is avoided. it can.

According to the second aspect of the present invention, the intake passage is formed in a substantially inverted triangular shape, and the upstream portion of the partition plate is located near the bottom of the inverted triangle, so that the intake control valve can be opened from the fully closed state. Accordingly, the passage area can be rapidly increased, and there is an effect that the required intake air amount can be taken in without delay at the time of sudden acceleration or the like.

[Brief description of the drawings]

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

FIG. 2 is a sectional side view of a main part of an intake control valve and a partition plate portion of the first embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a perspective view of a partition portion of the first embodiment.

FIG. 5 is a sectional view taken along line VV of FIG. 2;

FIG. 6 is a sectional side view showing an intake control device for an engine according to a second embodiment of the present invention.

FIG. 7 is a sectional side view showing an intake control device for an engine according to a third embodiment of the present invention.

FIG. 8 is a sectional side view showing an intake control device for an engine according to a fourth embodiment of the present invention.

FIG. 9 is a bottom view of the combustion chamber of the fourth embodiment.

FIG. 10 is a sectional side view showing an intake control device for an engine according to a fifth embodiment of the present invention.

FIG. 11 is a bottom view of the combustion chamber of the fifth embodiment.

FIG. 12 is a sectional side view showing an intake control device for an engine according to a sixth embodiment of the present invention.

FIG. 13 is a perspective view of a piston according to the sixth embodiment.

FIG. 14 is a sectional front view of the engine of the sixth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 17 Intake passage 17d Bottom wall 17b Top wall 20 Partition plate 20a Upstream (upstream end) 21 Intake control valve A Top wall side passage B Bottom wall side passage

Claims (2)

(57) [Claims] 1. An intake control valve, which narrows a bottom wall side portion of an intake passage when an intake air amount is low and causes intake air to be biased toward a top wall side of the intake passage, protrudes into the intake passage at the bottom wall. Movable between the fully open position to be immersed in the fully closed position and a bottom wall
Disposed in Noh, arranged a partition plate for dividing the downstream portion and the top wall-side passage and the bottom wall-side passage from the intake control valve of the intake passage, the cross-sectional at the downstream end of the top wall-side passage narrower set than the cross-sectional area of the area at the upstream end, absorption of the partition plate
The portion near the air valve opening is close to the valve stem of the intake valve
An intake control device for an engine, characterized in that the intake control device is formed so as to follow along . 2. The intake passage according to claim 1, wherein a cross-sectional shape of the intake passage is substantially inverted triangle, and an upstream end of the partition plate is located near a base of the triangle and substantially parallel to the base. An air intake control device for an engine.