JPH11107764A - Intake system for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form more violent tumbling in the inside of a combustion chamber by controlling the flow motion of intake by a control valve provided for an intake passage. SOLUTION: In this system, an intake passage is formed out of the intake port of a cylinder head 3, and of the passage 12 of a manifold 11, and a control valve 15 which controls the flow motion of intake air to form tumbling in the inside of a combustion chamber 5, is provided for the intake passage. The portion of the air intake passage located from the upstream side of the control valve 15 down to a place close to an intake valve, is formed into a straight shape, and a distance La from the control valve 15 to the combustion chamber 5 is so designed as to be 3 to 5 times as long as the diameter D of the passage in length at the set position of the control valve 15. A cut-out 17 is formed in the control valve in such a way that an opening part 18 is formed at the lower wall surface side of the air intake passage when the control valve 15 is fully closed. Besides, a swelling part 6e is formed at the upper part of the air intake passage, and the injection portion of a fuel injection valve 10 is thereby so designed as to be disposed at the aforesaid upper part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine, and more particularly to an intake system for an engine in which a control valve provided in an intake passage controls an intake flow to generate a tumble in a combustion chamber. It is.

[0002]

2. Description of the Related Art Conventionally, a device as disclosed in Japanese Patent Application Laid-Open No. Hei 8-218881 is known as an intake device for an engine as described above.

The intake system disclosed in this publication is an intake system applied to a lean burn engine that burns at an air-fuel ratio thinner than the stoichiometric air-fuel ratio. In this intake device, an intake passage provided with an intake control valve (hereinafter abbreviated as a control valve) bifurcates on the downstream side of the control valve, that is, on the downstream side in the flow direction of the intake air, and these branch passages are respectively burned. To the room. A cutout is formed in the upper part of the control valve corresponding to the branch passage on one side. Under a predetermined operating state, the control valve is fully closed, so that the control valve is mainly opened through the cutout. It is configured such that intake air is introduced into the side branch passage.

That is, by introducing intake air into the combustion chamber through one branch passage, a composite vortex is formed by swirl and tumble in the combustion chamber, thereby promoting the flow of the air-fuel mixture. Have been.

[0005]

By the way, conventionally,
Comparing tumble with swirl, it is considered that a swirl with higher sustainability is more advantageous in promoting the flow of the air-fuel mixture than a tumble in which the flow collapses in the compression stroke, and it is important to strengthen the swirl mainly. It was done. However, according to the tumble, the decrease in the kinetic energy of the tumble is converted into the turbulence energy of the air-fuel mixture due to the collapse in the compression stroke as described above. It has been experimentally recognized that the mixture is effectively promoted, and in recent years, forming only a tumble as a means for promoting the flow of the air-fuel mixture has become mainstream. Therefore, it has been an issue to form a stronger tumble in the combustion chamber.

When a strong tumble is formed, it is necessary to make the intake air flow into the combustion chamber so that more intake air flows from the upper wall portion of the combustion chamber along the wall surface on the exhaust valve side. Conventionally, as shown in the above-mentioned publication, by introducing intake air through a notch formed in an upper portion of a control valve, a drift of intake air is formed along an upper wall surface of an intake passage to form an upper wall portion of a combustion chamber. The intake air is made to flow easily.

However, as described above, it is difficult to form an appropriate intake air flow by forming a notch in a part of the control valve and introducing the intake air through the notch, and it is not always sufficient to strengthen the tumble. is not. That is, just by forming a notch in the upper part of the control valve as in the device of the above publication, for example, as shown in FIG. 15, the gas is introduced along the upper wall surface of the intake passage through the notch 52 of the control valve 51. A part of the intake air flows around the downstream side of the control valve where the notch 52 is not formed to form a vortex, and the main flow of the intake air is drawn to the vortex to change the course toward the lower wall surface of the intake passage 50. That is, in the figure, the intake flow is represented by a vector (arrow), and the denser the arrow, the stronger the intake flow. Therefore, it is difficult to flow a large amount of intake air along the upper wall portion of the combustion chamber 53, and the tumble cannot be sufficiently strengthened.

Therefore, when a strong tumble is to be generated by controlling the intake air flow by the control valve, the intake passage and the control valve must be sufficiently considered in consideration of the above-mentioned vortex generated downstream of the control valve. Need to be configured.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problem. In an intake device in which a tumble is generated in a combustion chamber by controlling intake air flow by a control valve provided in an intake passage, It is an object of the present invention to provide an intake device for an engine that can form a stronger tumble in a room.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a control valve for generating a tumble in a combustion chamber by controlling intake air flow in an intake passage having a downstream end opening to the combustion chamber. And an opening forming part that forms an opening when fully closed is provided in the control valve, and the fuel is supplied while the intake air flows through the opening by fully closing the control valve in a predetermined operation range. In an intake system for an engine configured to inject fuel downstream of a control valve, a straight portion is formed downstream of the control valve in the intake passage, and a bulging portion for arranging a fuel injection valve is connected above the straight portion. On the other hand, the opening is formed in the control valve such that the opening is formed near the lower wall surface of the intake passage (claim 1).

According to this device, a part of the intake air introduced through the opening wraps around the control valve and forms a vortex near the upper wall surface of the intake passage. Therefore, the intake air introduced from near the lower wall surface of the intake passage flows along the upper wall surface of the intake passage while being drawn by the vortex, thereby introducing the intake air from the upper wall surface of the combustion chamber along the side wall surface. It is easy to be done. In addition, "upper part" in the description of the claim,
“Lower” is a concept of a position relative to the combustion chamber, and does not always coincide with a physical position. In the claims, “upstream” and “downstream” mean “upstream” and “downstream” in the flow direction of intake air.

In the above apparatus, the distance from the control valve to the downstream end of the intake passage is set so as to be within a range of 3 to 5 times the diameter of the intake passage at the portion where the control valve is provided. It is desirable to form the intake passage (claim 2). In particular, it is effective to set the intake passage diameter within a range of 24 to 32 mm (claim 3). If the intake passage is formed within such a range, the above-described effects can be obtained more reliably.

Further, in the device according to the first aspect, the opening forming portion is located on the downstream side with respect to a plane orthogonal to the axis of the intake passage when the angle of the valve surface of the control valve at the time of full closing is set as a reference. It is preferable to set the angle within 10 ° in the direction or within 25 ° in the direction in which the opening forming portion is located on the upstream side (claim 4).

The nature of the vortex formed on the downstream side of the control valve greatly changes depending on the angle of the valve face. However, if the angle of the valve face is set within the above range, the upper wall portion of the intake passage can be formed. A vortex is formed which is effective in forming a drift along the flow. In particular, considering the assembly error of the control valve, etc.,
It is desirable to set the opening forming portion within a range of 0 ° to 10 ° in a direction in which the opening forming portion is located on the upstream side.

According to the first aspect of the present invention, the angle of the valve surface of the control valve when the control valve is fully closed is set to an angle substantially perpendicular to the axis of the intake passage, and the high speed of the engine is controlled. If the control valve is opened in the direction in which the opening forming portion is located on the upstream side in an operation range where the air-fuel ratio is lower than the vicinity of the stoichiometric air-fuel ratio on the high load side, Item 6), not only when the control valve is fully closed,
Even when the control valve is slightly opened, the above-described drift of the intake air is formed. Therefore, in the case where a high-speed, high-load, lean operation of the air-fuel ratio is required, it is possible to promote the formation of tumble in the control valve to promote the flow of the air-fuel mixture.

Further, in the apparatus according to the first or second aspect, the downstream side of the intake passage has a common portion which branches into two branch passages, and each downstream end of the two branch passages opens to the combustion chamber. In the case where the distance from the downstream end position of the common portion to the control valve is longer than the distance from the downstream end position of the common portion to the downstream end of the intake passage. Forming the intake passage (claim 7) is effective in forming the above-described intake air drift.

In this case, of the upper wall portion in the branch passage, at least a portion up to the vicinity of the valve shaft support position of the intake valve may be formed in a straight shape (claim 8), and the portion downstream of the common portion may be formed. If the intake passage from the end position to the control valve is formed in a straight shape (claim 9), the directivity of the intake air drift flowing along the upper wall surface of the passage as described above is effectively maintained. As a result, the intake air can be more reliably introduced along the upper wall portion of the combustion chamber.

In the apparatus according to any one of claims 2, 7, and 8, the downstream side of the intake passage has a common portion that branches into two branch passages, and each downstream end of the two branch passages has a combustion portion. In the case where the intake passage is configured to open to the chamber, the cross section of the intake passage extending from the upstream end position of the common portion to the control valve is formed in a wide flat shape in the direction in which the branch passages are arranged. Preferably, the opening forming portion is formed in a shape symmetrical in the arrangement direction with respect to an axis passing through the center in the arrangement direction (claim 10). If you do this,
The intake air flows into both branch passages evenly. That is, turbulence of the intake air in the combustion chamber due to uneven intake of the intake air is suppressed, which is advantageous in forming a strong tumble.

In this case, when the control valve is rotatably supported around a rotation axis extending in the direction in which the branch passages are arranged, and rotates around the rotation axis to open and close the intake passage. It is preferable that a notch formed by cutting a peripheral portion of the control valve in parallel with the rotation axis is formed as the opening forming portion of the control valve (Claim 11). It is preferable to provide the opening forming portion such that the size of the opening is 35% or less of the intake passage area in the portion where the control valve is provided (claim 12). In this way, it is possible to more reliably form the above-described intake air drift.

In order to solve the above-mentioned problems, the present invention is directed to controlling the flow of intake air upstream of an intake passage having a common portion which branches downstream into two branch passages and opens to a combustion chamber. A control valve for generating a tumble in the combustion chamber is provided, and an opening forming section for forming an opening when fully closed is provided in the control valve, and the opening is formed by fully closing the control valve in a predetermined operation range. In an intake system for an engine, in which fuel is injected downstream of the control valve while circulating intake air through the intake valve, an intake passage diameter at a position where the control valve is disposed is set within a range of 24 to 32 mm. The intake passage is formed so that the distance from the valve to the downstream end of the intake passage is within a range of 3 to 5 times the intake passage diameter, and the distance from the downstream end position of the common portion to the control valve is reduced. , The length is longer and straighter than the distance from the downstream end position of the mon portion to the downstream end portion of the intake passage, and the cross section of the intake passage from the upstream end position of the common portion to the control valve is formed in each branch passage. While forming the intake passage so as to have a wide flat shape in the arrangement direction, the control valve is configured to open and close the intake passage by rotating around a rotation axis extending in the arrangement direction of the branch passages,
As the opening forming portion, a cutout portion is formed in the control valve in which a peripheral portion on a lower side of the control valve is cutout in parallel with the rotation axis (claim 13).

According to this device, a part of the intake air introduced through the opening wraps around the control valve to form a vortex near the upper wall surface of the intake passage. Therefore, the intake air introduced from the vicinity of the lower wall surface of the intake passage flows along the upper wall surface of the intake passage while being drawn to the vortex, whereby the intake air is introduced from the upper wall surface of the combustion chamber along the side wall surface. It will be easier.

In the above device, the opening forming portion is provided such that the size of the opening is 35% or less of the intake passage area in the portion where the control valve is provided when the control valve is fully closed. (Claim 14). By doing so, it is possible to form the above-described intake air drift more effectively.

Further, in order to solve the above-mentioned problem, the present invention is to control the intake air flow upstream of an intake passage having a common portion which branches off into two branch passages and opens to a combustion chamber. A control valve for generating a tumble in the combustion chamber is provided, and an opening forming section for forming an opening when fully closed is provided in the control valve, and the opening is formed by fully closing the control valve in a predetermined operation range. In an intake system for an engine, in which fuel is injected downstream of the control valve while circulating intake air, a distance from the downstream end position of the common section to the control valve is set at a distance from the downstream end position of the common section. It is shorter than the distance to the downstream end of the intake passage, and the cross section of the intake passage extending from the upstream end position of the common portion to the control valve has a wide flat shape in the arrangement direction of the branch passages. While forming the intake passage, in which the opening is provided in the control valve the opening forming portion so as to be formed on the upper wall near the air intake passage (claim 1
5).

According to this device, a part of the intake air introduced through the opening wraps around the control valve and forms a vortex near the lower wall surface of the intake passage, but is introduced from the vicinity of the upper wall surface. The intake air will reach the downstream end of the intake passage before being completely drawn into this vortex. Therefore, while the intake air is introduced from near the upper wall surface of the intake passage, the intake air is easily introduced from the upper wall surface of the combustion chamber along the side wall surface.

In this device, it is preferable that an injection port portion of the fuel injection valve is provided downstream of a downstream end position of the common portion. With this configuration, the bulging portion can be interposed between the branch passages, and the space efficiency can be improved.

Further, in the apparatus according to the fifteenth aspect, when the control valve is fully closed, the size of the opening is set to be 35% or less of the intake passage area in a portion where the control valve is provided. It is desirable to form the notch so as to provide a forming portion (claim 17), and to form a straight intake passage from the downstream end position of the common portion to the control valve (claim 18). . By doing so, it becomes possible to make the intake air flow more effectively in the combustion chamber along the upper wall surface of the combustion chamber.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 schematically show an engine body to which an intake device according to an embodiment of the present invention is applied. In these drawings, an engine main body 1 includes a cylinder block 2 and a cylinder head 3, and the engine main body 1 includes a plurality of cylinders 4. A piston (not shown) is fitted into each cylinder 4, and a combustion chamber 5 is formed between the piston and the lower surface of the cylinder head 3. The downstream end of the intake port 6 and the upstream end of the exhaust port 7 are open to the combustion chamber 5.

The intake port 6 is a passage for intake formed integrally with the cylinder head 3, and has a common portion 6c that branches from an upstream port portion to two downstream port portions 6a and 6b (branch passages). The downstream ports 6a and 6b are open to the combustion chamber 5 in a state of being arranged in the cylinder row direction (the vertical direction in FIG. 2). The downstream ports 6a and 6b are opened and closed by the intake valve 8, respectively. The intake port 6 has a bulging portion 6 bulging upward from the upstream port portion to the common portion 6c.
e (a bulging portion) is formed, and an injection port portion of the fuel injection valve 10 is interposed in the bulging portion 6e. on the other hand,
The exhaust port 7 has two upstream port portions 7a and 7b, and these upstream port portions 7a and 7b open to the combustion chamber 5 and are opened and closed by an exhaust valve 9. An ignition plug (not shown) is provided at the upper center of the combustion chamber 5.

The engine body 1 further has a manifold 11 attached to the cylinder head 3. The manifold 11 is provided with passages 12 for respective cylinders connected to a surge tank (not shown), and these passages 12 communicate with the respective intake ports 6. That is,
The passage 12 of the manifold 11 and the intake port 6 of the cylinder head 3 constitute an intake passage of the present application for introducing intake air into the combustion chamber 5. In the following description, a passage constituted by the intake port 6 and the passage 12 will be referred to as an “intake passage” as described above.

The intake passage is provided with a control valve 15 for controlling the flow of the intake air to generate a tumble in the combustion chamber 5. The control valve 15 is arranged at a downstream end portion of the passage 12 and rotates from a fully closed state to a fully open state around a rotating shaft 16 extending in a cylinder row direction (a direction in which the downstream port portions 6a and 6b are arranged). It is possible.

Here, the configuration of the intake passage and the control valve 15 will be described in more detail.

The intake passage extends from at least the location of the control valve 15 to the downstream end 6d of the common portion 6c (both downstream port portions 6d).
a, 6b are completely separated from each other), and in the embodiment shown in the figure, particularly, in the embodiment shown in the figure, the intake passage is formed straight from a position upstream of the control valve 15 to a position near the intake valve 8. Is formed.
Then, it curves downward from a position near the intake valve 8 and communicates with the combustion chamber 5.

Each of the downstream port portions 6a and 6b has a circular cross section of the same shape, and the portion upstream of the common portion 6c is, for example, at the axis of the intake passage (two-dot chain line in FIGS. 1 and 2). The cross section perpendicular to the horizontal is long, that is, each downstream port 6
It has an elliptical shape long in the arrangement direction of a and 6b. This ellipse has a shape symmetrical to the left and right with respect to an axis orthogonal to the axis, and by having such a cross-sectional shape, intake air is uniformly supplied from the upstream port portion to each of the downstream port portions 6a and 6b. It can be introduced. Note that the upstream portion of the intake port 6 has a cross-sectional shape in which the above-mentioned bulging portion 6d is continuously provided on the basis of such an elliptical shape.

In the intake passage, the distance Lb from the downstream end 6d of the common portion 6c to the control valve 15 is longer than the distance Lc from the downstream end 6d of the common portion 6c to the downstream end of the intake passage. Set and control valve 1
5 from the downstream end of the intake passage to the control valve 15
The intake passage is configured so as to have a diameter D of the passage cross section in the arrangement portion, specifically, a length of 3 to 5 times the minor diameter in the elliptical shape. In general engine specifications, it is desirable to set the diameter D within the range of 24 to 32 mm.

As shown in FIG. 3, the control valve 15 has a horizontally-long elliptical shape corresponding to the cross-sectional shape of the intake passage.
(Opening formation part) is formed. Thus, when the control valve 15 is fully closed, a semilunar opening 18 is formed in the lower portion of the passage 12. This notch 17
The size of the opening 18 by the control valve 15 is preferably
Is set to a range of 35% or less of the intake passage area of the arrangement portion. Note that the shape of the notch 17 is not limited to that shown in FIG. 3. For example, as shown in FIG.
The notch 17 may be provided only at the intermediate portion in the direction of the rotation axis, or the notch may be provided leaving the peripheral portion as shown in FIG.

The angle of the valve surface when the control valve 15 is fully closed is
As shown in FIG. 1, it is set so as to be substantially perpendicular to the axis of the intake passage. The control valve 15 can be opened and closed between the fully closed state and the fully opened state where the valve surface of the control valve 15 is substantially in the same direction as the axis.

According to the intake system of the present embodiment as described above, when the control valve 15 is fully closed in the low-load operation range, the control valve 15 passes through the opening 18 formed by the notch 17 and is located on the downstream side. A tumble is generated in the combustion chamber 5 by the intake air flowing through the combustion chamber 5. In this case, since the opening 18 is formed on the lower wall surface side of the intake passage, the function of generating tumble is enhanced, and a stronger tumble can be generated in the combustion chamber 5.

That is, according to the above-described intake device,
When the intake air is introduced into the intake port 6 through the opening 18, a part of the air enters the upper wall surface where the opening 18 is not formed downstream of the control valve 15 as shown in FIG. A vortex is formed near the upper wall of the passage.
Therefore, the main flow of the intake air is affected by the swirl flow, that is, attracted by the swirl flow, flows toward the upper wall surface side of the intake port 6, and reaches the combustion chamber 5 along the wall surface. In this case, the main flow of the intake air immediately after passing through the opening passes through the lower wall surface side, while the bulging portion 6e is provided at the upper part of the intake passage as described above. The flow from the lower wall surface side to the upper wall surface side of the intake port 6 is favorably obtained without being dispersed and weakened by the outlet portion 6e. The intake valve 8 in the intake passage
Since most of the downstream side of the control valve reaching the vicinity of is formed in a straight shape, the flow of the intake air flowing along the upper wall surface, that is, the drift of the intake air is appropriately maintained. Therefore, most of the intake air introduced into the combustion chamber 5 flows from the upper wall surface of the combustion chamber 5 along the cylinder side on the exhaust valve side, whereby a strong tumble is formed. In FIG. 6, the intake flow is represented by a vector (arrow), and the denser the arrow, the stronger the intake flow.

By the way, in the above-described intake system, the distance La from the control valve 15 to the combustion chamber 5 is controlled by the control valve 1 as described above.
5 to 3 to 5 times the diameter D of the passage cross section (La
/ D = 3 to 5), but this is because La / D is less than 3 or 5 as shown in FIG.
This is because the tumble ratio sharply decreases in a configuration of the intake passage that exceeds tumble, that is, the tumble is weakened, and it is not expected that the tumble is strengthened.

This can be considered as follows.
That is, as shown in FIG. 8, the flow of the intake air in the intake passage is directed from the lower wall surface side to the upper wall surface side of the intake passage under the influence of the vortex (the vortex indicated by the symbol α). When the flow is biased toward the upper wall surface of the intake passage, a vortex (a vortex indicated by reference numeral β) is formed between the flow and the lower wall surface of the intake passage, and along the upper wall surface of the intake passage as shown in FIG. Under the influence of the vortex, the intake air flowing again is directed from the upper wall surface side to the lower wall surface side of the intake passage again.

Therefore, when La / D exceeds 5 in the relative relationship between the diameter D of the passage cross section and the distance La, the relationship between the intake air flow and the opening position of the combustion chamber 5 causes The downstream end portion of the intake passage is located at a position where the intake air flowing along the upper wall surface is again directed to the lower wall surface side, in other words, the intake air flows at or near the lower wall surface of the intake passage at the downstream end portion of the intake passage. The passage configuration is as follows. Therefore, when La / D exceeds 5, it is considered that the tumble is weakened.

Conversely, when La / D is less than 3, the downstream end portion of the intake passage is located upstream of the position where the drift of the intake air is formed on the upper wall surface of the intake passage. At the opening of the combustion chamber 5, a passage structure is formed such that the intake air flows in the lower part of the intake passage or in the vicinity thereof. Therefore, it is considered that the tumble is similarly weakened when La / D is less than 3.

FIG. 9 shows the result of measurement of the difference between the value of La / D and the average flow velocity of the upper half and the lower half of the intake passage near the combustion chamber 5. As described above, when La / D is less than 3, the difference in the average flow velocity is a negative value, that is, the upper half has a lower flow velocity than the lower half.
Therefore, in the configuration of the intake passage in which La / D is less than 3,
In the vicinity of the downstream end of the intake passage, the flow on the upper side is weakened, and in some cases, backflow may occur on the upper side. That is, it is considered that this reduces the intake air flowing along the upper wall surface of the combustion chamber 5 and weakens the tumble.

Therefore, in order to generate a strong tumble, it is effective to configure the intake passage so that La / D = 3 to 5.

Further, in the above-described intake device, when the control valve 15 is fully closed as described above, the size of the opening 18 is set to be 35% or less of the intake passage area of the portion where the control valve 15 is disposed. As shown in FIG. 10, when the opening area ratio is set to 35% or less, the turbulent energy of the air-fuel mixture in the combustion chamber 5 sharply increases, that is, the strong This is because tumble occurs. This is advantageous in that the intake speed is faster in the generation of tumble, and in this respect, the opening area ratio of the opening 18 is 35%.
It can be considered that the intake speed can be effectively increased by setting the following. Therefore, in order to generate a strong tumble, it is advantageous to configure the control valve 15 so that the opening area ratio is 35% or less.

In the engine body 1 of the embodiment, the angle of the valve surface when the control valve 15 is fully closed is set so as to be perpendicular to the axis of the intake passage. It is not necessary that the notch 17 is located on the downstream side (the left side in FIG. 11) in a forward direction (shown by a solid line) on the basis of a case perpendicular to the axis of the intake passage (shown by a solid line) as shown in FIG. The angle of the valve face when fully closed may be set so that the notch 17 is inclined in the negative direction (direction indicated by the two-dot chain line) located on the upstream side. In this case, the angle of the valve face is set within a range of 10 ° (+ 10 °) in the positive direction and within 25 ° (−25 °) in the negative direction, based on a case perpendicular to the axis of the intake passage. Is preferred.

That is, if the angle is set outside the above angle range, the turbulence energy of the air-fuel mixture in the combustion chamber 5 is significantly reduced. This is because, at an angle exceeding + 10 °, the vortex formed immediately downstream of the control valve 15 causes the control valve 1
This is because a large swirl flows from 5 to the vicinity of the intake valve 8 and the intake air flowing in through the opening 18 is not sufficiently drawn to the upper portion of the intake passage. At a large angle, a vortex as shown by the symbol β in FIG. 8 is formed relatively close to the control valve 15, so that the intake air flowing along the upper wall surface of the intake passage returns to the lower end portion at the downstream end portion of the intake passage. This is probably because the light is directed toward the wall.

In this case, the allowable range in the negative direction is large as described above.
As shown in the figure, the turbulence energy changes slowly,
In consideration of the assembly error of the control valve 15, etc., the above angle is set to -1.
It is desirable to set in the range of 0 ° to 0 °.

In the above device, the angle of the valve surface when the control valve 15 is fully closed is set to be perpendicular to the axis of the intake passage. Alternatively, the control valve 15 can be rotated in the positive direction. In the above-described embodiment, the control valve 15 is rotated in the negative direction to open and close the intake passage. The intake passage may be opened and closed by rotating the intake passage. However, if the control valve 15 is rotated in the negative direction to open and close the intake passage, the control valve 15 is opened if the angle of the control valve 15 is −25 ° to 0 ° as described above. Even in the depressed state, it is possible to form the drift of the intake air along the upper wall surface of the intake passage as described above. Therefore, for example, when the engine is operating at a high rotation speed and a high load,
And the control valve 1 slightly like the operating range where the air-fuel ratio is lean
In the case of opening 5, there is an advantage that a strong tumble can be generated to improve the flammability.

In the above-described intake device, the intake valve 8
The intake passage is curved downward from the vicinity of the valve shaft support position to the downstream side, and if the intake air flows along the upper wall surface at the valve shaft support position, the intake air naturally flows to the upper part of the intake passage downstream of the intake passage. It will flow along the wall. Therefore, for example, from the control valve 15 to the downstream end 6d of the common portion 6c
If the upper wall surface of the intake passage is formed in a straight shape from the downstream end 6d of the common portion 6c to the vicinity of the valve shaft supporting position of the intake valve 8, the common portion is formed. On the downstream side, the resistance to the drift along the upper surface of the intake passage is reduced as much as possible, and a strong tumble can be generated.

Next, a second embodiment of the present invention will be described.

FIG. 13 schematically shows an engine body according to the second embodiment. The engine body 1 'also has the basic configuration of the engine body 1 of the first embodiment.
The same reference numerals are given to the common parts and the description will be omitted, and the differences from the engine body 1 will be described in detail below.

Engine body 1 'according to the second embodiment
In the first embodiment, the intake passage from the control valve 15 to the combustion chamber 5 is set relatively short as compared with the engine main body 1, and the intake passage is formed such that, for example, La / D is less than 3. . Further, in the intake passage, a distance L from the downstream end 6d of the common portion 6c to the downstream end of the intake passage is set.
c is set longer than the distance Lb from the downstream end 6d to the control valve 15.

Further, a notch 17 is formed in the control valve 15 so as to form a semilunar opening 18 in the upper part of the passage 12 when the outer control valve 15 is fully closed. Note that, in FIG.
The bulging portion, the fuel injection valve and the like are omitted.

Also in the case of the second embodiment described above, when the control valve 15 is fully closed in the low-load operation range, the control valve 15 passes through the opening 18 formed by the cutout 17. A tumble is generated in the combustion chamber 5 by the intake air flowing downstream.

More specifically, when the intake air is introduced into the intake port 6 through the opening 18 formed in the upper part of the passage 12, a part of the intake air is located downstream of the control valve 15 as shown in FIG. The air flows around the lower wall portion where the opening 18 is not formed, and forms a vortex on the lower wall portion of the intake port 6. Therefore, the main flow of the intake air tends to flow toward the lower wall surface of the intake port 6 under the influence of the vortex. However, since La / D is less than 3, and the intake passage from the control valve 15 to the combustion chamber 5 is set relatively short,
The main flow of the intake air reaches the curved portion of the intake port 6 before reaching the lower wall surface of the intake port 6, and as a result, flows into the combustion chamber 5 along the upper wall surface of the intake port 6. Therefore, most of the intake air introduced into the cylinder 4 flows from the upper wall surface of the combustion chamber 5 along the side wall surface on the exhaust valve side, whereby a strong tumble is formed.

Therefore, in the engine body 1 'of the second embodiment, similarly to the engine body 1 of the first embodiment, a strong tumble is formed in the combustion chamber 5. Can be.

In the structure of the engine body 1 ', the intake passage from the control valve 15 to the combustion chamber 5 is relatively short as described above, and the opening of the combustion chamber 5 extends from the downstream end 6d of the common portion 6c. Since the intake passage is configured so that the distance Lc to the portion is longer than the distance Lb from the downstream end 6d to the control valve 15, an injection valve having two injection ports is adopted as a fuel injection valve, It is preferable that this is disposed in the space between the downstream port portions 6a and 6b so that each nozzle port faces the downstream port portions 6a and 6b. In this way, each downstream port 6a, 6
It is a reasonable arrangement that makes effective use of the space between b,
The periphery of the intake port 6 can be made compact.

[0060]

As described above, according to the present invention, a control valve for generating a tumble in a combustion chamber by controlling the flow of intake air is provided in an intake passage, and the control valve is fully closed in a predetermined operating range. In the intake device, which injects fuel while allowing intake air to flow through the opening of the control valve,
The control valve is configured such that the opening is formed in the vicinity of the lower wall surface of the intake passage, and thereby the intake air introduced along the lower wall surface of the intake passage is swirled by the vortex of the intake air formed immediately downstream of the control valve. To form a drift of the intake air flowing along the upper wall surface of the intake passage by directing toward the upper wall surface of the intake passage, while forming the control valve downstream side of the intake passage in a straight shape, and A bulging portion for fuel injection is connected to the combustion chamber, so that it is possible to flow into the combustion chamber without disturbing the above-described drift, so that most of the intake air flows from the upper wall surface of the combustion chamber to the side wall surface. Can be effectively introduced along. Therefore, a strong tumble can be effectively formed in the combustion chamber.

In particular, in the above configuration, the intake valve is controlled such that the distance from the control valve to the downstream end of the intake passage is within a range of 3 to 5 times the intake passage diameter at the portion where the control valve is provided. If a passage is formed, a strong tumble can be generated more effectively.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an engine body to which an intake device (first embodiment) of the present invention is applied.

FIG. 2 is a schematic plan view showing an intake passage.

FIG. 3 is a side view showing a configuration of a control valve.

FIG. 4 is a side view showing another example of the control valve.

FIG. 5 is a side view showing another example of the control valve.

FIG. 6 is a diagram showing a flow rate of intake air in an intake passage.

FIG. 7 is a diagram showing a relationship between a ratio (La / D) of an intake passage diameter (D) to a distance (La) from a control valve to a combustion chamber and a tumble ratio.

FIG. 8 is a schematic diagram illustrating a flow of intake air in an intake passage.

FIG. 9 is a diagram showing the relationship between La / D and the difference between the upper half average flow velocity and the lower half average flow velocity in the intake passage.

FIG. 10 is a diagram showing a relationship between an opening ratio of a control valve and turbulent energy in a combustion chamber.

FIG. 11 is a diagram illustrating a valve face angle of a control valve when fully closed.

FIG. 12 is a diagram showing the relationship between the valve face angle of the control valve and the turbulence energy in the combustion chamber when fully closed.

FIG. 13 is a schematic sectional view showing an engine main body to which the intake device (first embodiment) of the present invention is applied.

FIG. 14 is a diagram showing a flow rate of intake air in an intake passage.

FIG. 15 is a diagram showing a flow rate of intake air in an intake passage in a conventional intake device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder block 3 Cylinder head 4 Cylinder 5 Combustion chamber 6 Intake port 6a, 6b Downstream port part 6c Common part 6d Downstream end 7 Exhaust port 7a, 7b Upstream port part 8 Intake valve 9 Exhaust valve 10 Fuel injection valve 11 Manifold DESCRIPTION OF SYMBOLS 12 Passage 15 Control valve 16 Rotating shaft 17 Notch 18 Opening

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumihiko Saito 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Toshihide Yamamoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Yoshihisa Noo 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Pref.

Claims (18)

[Claims] A control valve for controlling a flow of intake air to generate a tumble in a combustion chamber is provided in an intake passage having a downstream end opening to the combustion chamber, and an opening forming section for forming an opening when fully closed is provided. An intake system for an engine provided in the control valve and injecting fuel downstream of the control valve while allowing intake air to flow through the opening by fully closing the control valve in a predetermined operation range. A straight portion is formed downstream of the control valve in the intake passage, and a bulging portion for arranging the fuel injection valve is continuously provided above the straight portion, while the opening is formed near a lower wall surface of the intake passage. An intake device for an engine, wherein the opening forming portion is provided in a control valve so as to be operated. 2. The intake passage is formed such that a distance from the control valve to a downstream end of the intake passage is within a range of 3 to 5 times a diameter of the intake passage in a portion where the control valve is provided. The intake device for an engine according to claim 1, wherein: 3. The intake system for an engine according to claim 2, wherein said intake passage diameter is set within a range of 24 to 32 mm. 4. An angle of a valve surface of a control valve when fully closed,
With reference to a plane perpendicular to the axis of the intake passage, the opening is set within a range of 10 ° in the direction in which the opening is located on the downstream side, or within 25 ° in the direction in which the opening is located on the upstream side. The intake device for an engine according to claim 1, wherein: 5. An angle of a valve surface of a control valve when fully closed,
5. The intake device for an engine according to claim 4, wherein the opening forming portion is set within a range of 0 [deg.] To 10 [deg.] In a direction in which the opening forming portion is located on the upstream side with respect to a plane orthogonal to the axis of the intake passage. 6. An angle of a valve surface of the control valve when the control valve is fully closed is set to an angle substantially orthogonal to an axis of the intake passage, and is on a high-speed, high-load side of the engine, and 2. The control valve according to claim 1, wherein the control valve is opened in a direction in which the opening forming portion is located on the upstream side in an operation range in which the air-fuel ratio has a smaller air-fuel ratio than the vicinity of the stoichiometric air-fuel ratio.
An intake device for an engine as described. 7. The intake passage has a common portion whose downstream side branches into two branch passages, and each downstream end of each of the two branch passages is configured to open to a combustion chamber.
The distance from the downstream end position of the common portion to the control valve is:
3. The intake system for an engine according to claim 1, wherein the intake passage is formed so as to be longer than a distance from a downstream end position of a common portion to a downstream end of the intake passage. 8. An upper wall portion in the branch passage,
8. The intake system for an engine according to claim 7, wherein at least a portion up to a position near a valve shaft support position of the intake valve is formed in a straight shape. 9. The intake system for an engine according to claim 7, wherein an intake passage extending from a downstream end position of the common portion to the control valve is formed in a straight shape. 10. The intake passage has a common portion whose downstream side is branched into two branch passages, and each downstream end of each of the two branch passages is configured to open to a combustion chamber. The cross section of the intake passage from the upstream end position of the common portion to the control valve is formed in a wide flat shape in the direction in which the branch passages are arranged, and the opening forming portion is formed with respect to an axis passing through the center in the arrangement direction. 9. The intake device for an engine according to claim 2, wherein the intake device is formed in a symmetrical shape in the arrangement direction. 11. The control valve, wherein the control valve is rotatably supported around a rotation axis extending in a direction in which the branch passages are arranged, and rotates around the rotation axis to open and close the intake passage. 11. The intake device for an engine according to claim 10, wherein a cutout portion formed by cutting out a peripheral portion of the control valve is provided in parallel with the rotation axis as the opening forming portion of the valve. 12. The method according to claim 12, wherein the size of the opening is 35% or less of an area of the intake passage in a portion where the control valve is provided when the control valve is fully closed. The intake device for an engine according to claim 10 or 11, wherein: 13. A control valve for controlling a flow of intake air to generate a tumble in the combustion chamber is provided on an upstream side of an intake passage having a common portion that branches off into two branch passages and opens to the combustion chamber. At the same time, an opening forming part that forms an opening when fully closed is provided in the control valve, and the control valve is fully closed in a predetermined operation range to flow fuel through the opening and flow the fuel through the control valve. In the intake system for an engine, the intake valve diameter is set within a range of 24 to 32 mm at a position where the control valve is provided, and a distance from the control valve to a downstream end of the intake passage is set. Is formed within a range of 3 to 5 times the diameter of the intake passage, and the distance from the downstream end position of the common portion to the control valve is reduced from the downstream end position of the common portion to the downstream of the intake passage. end To the control valve from the upstream end position of the common portion, and the intake passage is formed so as to have a wide flat shape in the arrangement direction of the branch passages. While forming the passage, the control valve is configured to open and close the intake passage by rotating around a rotation shaft extending in the arrangement direction of the branch passages, and as the opening forming portion, in parallel with the rotation shaft. An intake device for an engine, wherein a cutout portion obtained by cutting out a lower peripheral portion of the control valve is provided in the control valve. 14. The opening forming portion is provided such that the size of the opening is 35% or less of the intake passage area in the portion where the control valve is provided when the control valve is fully closed. The intake device for an engine according to claim 13, wherein: 15. A control valve for controlling a flow of intake air to generate a tumble in the combustion chamber is provided on an upstream side of an intake passage having a common portion that branches into two branch passages on the downstream side and opens into the combustion chamber. At the same time, an opening forming part that forms an opening when fully closed is provided in the control valve, and the control valve is fully closed in a predetermined operation range to flow fuel through the opening and flow the fuel through the control valve. The distance from the downstream end of the common section to the control valve is smaller than the distance from the downstream end of the common section to the downstream end of the intake passage. And the intake passage is formed such that the cross section of the intake passage from the upstream end position of the common portion to the control valve has a wide flat shape in the direction in which the branch passages are arranged. An intake device for an engine, wherein the opening forming portion is provided in a control valve so as to be formed near an upper wall surface of an intake passage. 16. The intake system for an engine according to claim 15, wherein an injection port portion of the fuel injection valve is disposed downstream of a downstream end position of the common portion in the intake passage. 17. The apparatus according to claim 17, wherein the size of the opening is 35% or less of an intake passage area in a portion where the control valve is provided when the control valve is fully closed. The intake device for an engine according to claim 15, wherein 18. An intake system for an engine according to claim 15, wherein an intake passage extending from a downstream end position of said common portion to said control valve is formed in a straight shape.