WO2023053377A1 - Air intake structure for internal combustion engine - Google Patents

Abstract

The present disclosure is directed to a configuration that, in an internal combustion engine configured such that an intake channel is divided by a partitioning portion, securing of tumble performance is enabled while enabling relaxing of clearance control of an intake control valve that can also be referred to as a tumble valve. An intake structure S in an internal combustion engine according to an embodiment includes: a main partitioning portion 62 that partitions an intake channel 38 into a first intake channel 64 serving as a tumble channel and a second intake channel 66; a sub-partitioning portion 72 provided so as to form a third intake channel 68 and a fourth intake channel 70 in the first intake channel 64; and an intake control valve 76c provided upstream of the main partitioning portion 62. When the intake control valve 76c is in a state closing off the second intake channel 66 and the fourth intake channel 70, a first gap G1 portion is formed between the sub-partitioning portion 72 and a valve element 76d of the intake control valve 76c, and a second gap portion G2 is formed between an intake channel wall face 77a and the valve element 76d.

Description

Intake structure of internal combustion engine

The present invention relates to an intake structure for an internal combustion engine provided with partitions for dividing an intake passage into a plurality of sections.

Various intake structures for internal combustion engines have been proposed in which the intake passage on the downstream side of the throttle valve is divided into a plurality of passages by partitions. For example, in the intake structure for an internal combustion engine disclosed in Patent Document 1, a tumble valve is provided downstream of the throttle valve, and a partition plate portion, which is a partition portion, is provided downstream of the tumble valve from the inlet pipe to the intake port, The partition plate partitions the intake passage into a lower secondary passage and an upper main passage. The lower secondary passage serves as a tumble passage, and the tumble valve substantially opens and closes the upper main passage.

Japanese Patent No. 6714764

Conventionally, for example, when the operating state of the internal combustion engine is in the low load region, the tumble valve is closed to generate a tumble flow in the combustion chamber with intake air from the tumble flow path. However, if a passage other than the tumble flow passage in the tumble valve, for example, the upper main flow passage is less blocked, the intake flow will leak into the main flow passage, and the intake air from the tumble flow passage will not generate a tumble flow. It is likely to weaken.

On the other hand, in order to increase the degree of occlusion of the tumble valve when closed, it is necessary to manage the clearance between the tumble valve and the wall surface of the intake passage. This clearance management can result in increased costs.

An object of the present invention is to make it possible to relax the clearance management of an intake control valve, which may also be referred to as a tumble valve, and to ensure tumble performance in an internal combustion engine in which an intake passage is divided by partitions. The object is to provide a configuration that makes it possible.

In order to achieve the above object, one aspect of the present invention is
a main partition that divides an intake passage leading to a combustion chamber of an internal combustion engine into a first intake passage serving as a tumble flow passage for generating a tumble flow in the combustion chamber and a second intake passage;
A sub-partition provided in the first intake passage so as to form a third intake passage and a fourth intake passage, wherein the fourth intake passage separates the third intake passage and the second intake passage. a sub-partition formed to have a smaller cross-sectional area than the second intake passage and positioned between;
an intake control valve provided upstream of the main partition,
When the intake control valve is in a state of closing the second intake passage and the fourth intake passage, a first gap is formed between the sub-partition and the valve body of the intake control valve, and There is provided an intake structure for an internal combustion engine, characterized in that a second gap is formed between the intake passage wall surface on the side opposite to the sub-partition of the intake control valve and the valve body.

According to the above configuration, the first intake passage is provided with the sub-partition so as to form the third intake passage and the fourth intake passage, and the fourth intake passage separates the third intake passage and the second intake passage. is formed to have a cross-sectional area smaller than that of the second intake passage and positioned between the sub-partition and the intake control valve when the intake control valve is in a state of closing the second intake passage and the fourth intake passage. A first clearance is formed between the valve and the valve body of the valve, and a second clearance is formed between the intake passage wall surface on the side opposite to the sub-partition of the intake control valve and the valve body. be. Therefore, the flow of intake air that has passed through the first and second gaps can be urged to the fourth intake passage, which can serve as a tumble flow path. Therefore, tumble performance can be ensured. In addition, since the intake control valve is designed to form the first and second clearances, clearance management of the intake control valve is relaxed compared to increasing the degree of blockage of the intake control valve when the valve is closed. be able to. Therefore, according to the intake structure of the internal combustion engine, it is possible to secure the tumble performance while making it possible to relax the clearance management of the intake control valve.

Preferably, when the direction of the cylinder axis from the crankshaft side to the cylinder head side is defined as a first direction, the main partition section defines the intake passage as the first intake passage and the first intake passage of the first intake passage. The sub-partition separates the first intake passage from the third intake passage and the fourth intake passage on the first direction side of the third intake passage. provided to form With this configuration, it is possible to more preferably generate a tumble flow.

Preferably, the first clearance is located downstream of the second clearance in the intake flow direction. With this configuration, when the intake control valve is in a state of closing the second intake passage and the fourth intake passage, it is possible to cause the intake air to more preferably flow into the fourth intake passage, which may serve as a tumble passage.

Preferably, each of the first gap and the second gap has a gap width equal to or less than the thickness of the main partition. With this configuration, when the intake control valve is in a state of closing the second intake passage and the fourth intake passage, the intake air flows into the first intake passage including the third intake passage and the fourth intake passage that can be a tumble passage. can be further encouraged.

Preferably, the intake structure of the internal combustion engine described above is a confluence portion where the third intake passage and the fourth intake passage merge, and the first intake passage is connected to the second intake passage via the confluence portion. It further includes a confluence section that merges with the. With this configuration, the intake air from the first intake passage having the third intake passage and the fourth intake passage can have strong directivity, and the tumble performance can be further ensured.

Preferably, the cross-sectional area perpendicular to the flow direction on the downstream side of the upstream end of the merging portion is smaller than the sum of the cross-sectional areas of the third intake passage and the fourth intake passage. The confluence section is partitioned. With this configuration, when the intake air from the third intake passage and the intake air from the fourth intake passage merge at the confluence portion and flow into the second intake passage, the flow velocity of the intake air can be kept high.

Preferably, the merging portion is defined so that the intake air from the first intake passage through the merging portion flows into the combustion chamber at a smaller entrance angle than the intake air from the second intake passage. there is With this configuration, the intake air that has passed through the first intake passage can be introduced into the combustion chamber while maintaining strong directivity, so that a strong tumble flow can be generated in the combustion chamber.

Preferably, the intake control valve is configured to be able to open and close the second intake passage and the fourth intake passage, and has a first position for closing the second intake passage and the fourth intake passage, and a first position for closing the second intake passage and the fourth intake passage. It has a second position in which the second intake passage is closed and the fourth intake passage is opened, and a fully open position. With this configuration, it is possible to more preferably secure an intake air amount according to the operating state while appropriately generating a tumble flow.

Preferably, the intake control valve includes a single valve member that rotates integrally with a valve shaft, and a recess that allows movement of the valve member is provided in a wall that defines the intake passage. ing. With this configuration, the amount of intake air can be more easily adjusted by controlling the movement of a single valve member, and the recess can improve the opening and closing function of the valve member. .

Preferably, when the intake control valve is in a state of closing the second intake passage and the fourth intake passage, one end side half of the valve member of the intake control valve is positioned in the direction of flow of intake air about the valve shaft. The valve member is located downstream and forms an obtuse angle with the sub-partition portion downstream of the one end half, and the other end half of the valve member is located upstream and is the other end half. form an acute angle with the wall of the recess on the downstream side of the . With this configuration, when the intake control valve is in a state of closing the second intake passage and the fourth intake passage, it is possible to further promote the flow of the intake air that has passed through the intake control valve toward the fourth intake passage.

According to the above aspect of the present invention, since it has the above configuration, in an internal combustion engine in which the intake passage is configured to be divided by the partition, it is possible to relax the clearance management of the intake control valve and improve the tumble performance. can be ensured.

1 is a cross-sectional view showing a schematic configuration of an internal combustion engine according to one embodiment of the present invention; FIG. FIG. 2 is a diagram showing a three-dimensional model of a portion of an intake passage on the downstream side of a throttle valve in the internal combustion engine of FIG. 1; 3 is a view of the three-dimensional model of FIG. 2, viewed from a different angle than that of FIG. 2; FIG. FIG. 2 is a diagram showing a valve body of a tumble valve in the internal combustion engine of FIG. 1; FIG. 2 is a top view of a three-dimensional model including an intake passage portion downstream of a throttle valve and a tumble valve and an exhaust port in the internal combustion engine of FIG. 1 ; FIG. 6 is a view of the three-dimensional model of FIG. 5 viewed from a direction orthogonal to the cylinder axis and orthogonal to the intake flow direction; FIG. 7 is a cross-sectional view of the three-dimensional model of FIG. 6 at a position along line VIIA-VIIA; FIG. 7 is a cross-sectional view of the three-dimensional model of FIG. 6 at a position along line VIIB-VIIB; FIG. 7 is a cross-sectional view of the three-dimensional model of FIG. 6 at a position along line VIIC-VIIC; FIG. 7 is a cross-sectional view of the three-dimensional model of FIG. 6 at a position along the VIID-VIID line; FIG. 4 is a diagram for explaining the flow of intake air through a butterfly valve; FIG. 10 is a further diagram for explaining the flow of intake air by the butterfly valve; 2 is a diagram for explaining the flow of intake air around a tumble valve, which is an intake control valve, in the internal combustion engine of FIG. 1; FIG.

Hereinafter, an embodiment according to the present invention will be described based on the accompanying drawings. The same parts (or configurations) are given the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

A schematic configuration of an internal combustion engine 10 according to one embodiment of the present invention is shown in FIG. FIG. 1 is a cross-sectional view of an internal combustion engine 10 along an axis (cylinder axis) C of a cylinder bore 12b of a cylinder block 12 of the internal combustion engine 10. FIG.

A piston 15 that reciprocates in the cylinder bore 12b of the cylinder block 12 is connected to the crankpin of the crankshaft 17 of the crankcase portion 16 by a connecting rod 18. A combustion chamber 20 is formed between the top surface 15a of the piston 15 slidably fitted in the cylinder bore 12b of the cylinder block 12 and the combustion chamber ceiling surface 14a of the cylinder head 14 facing the top surface 15a. be.

The internal combustion engine 10 employs a SOHC type two-valve system, and a valve mechanism 22 is provided in the cylinder head 14 . A cylinder head cover 24 is overlaid on the cylinder head 14 so as to cover the valve mechanism 22 . In order to transmit power to the valve mechanism 22 in the cylinder head cover 24, an endless cam chain (not shown) is provided on one side of the crankcase portion 16, the cylinder block 12, and the cylinder head 14 in the crankshaft direction. A camshaft 26 and a crankshaft 17 are installed through a cam chain chamber, and the camshaft 26 rotates in synchronism with the crankshaft 17 at a rotation speed of 1/2. An ignition plug is inserted into the combustion chamber 20 from the opposite side of the cam chain chamber (the other side in the crankshaft direction) of the cylinder head 14 .

In the cylinder head 14, from an intake valve port 28 and an exhaust valve port 30 that open to the ceiling surface 14a of the combustion chamber, an intake port 32 and an exhaust port 34 are formed so as to extend while curving in directions vertically separating from each other. The upstream end of the intake port 32 opens toward the upper side of the cylinder head 14 and is connected to an inlet pipe 36 to form a continuous intake passage 38. A throttle body 40 is connected to the upstream side of the inlet pipe 36. be.

The downstream end of the exhaust port 34 opens downward from the cylinder head 14 and is connected to the exhaust pipe 42 . An exhaust purification device and a silencer may be provided downstream of the exhaust pipe 42 .

A cylindrical intake valve guide 44 is integrally fitted to the curved outer wall portion 32a of the intake port 32 in the cylinder head 14. An intake valve 46 slidably supported by an intake valve guide 44 opens and closes an intake valve port 28 of the intake port 32 facing the combustion chamber 20 .

Also, an exhaust valve 50 slidably supported by an exhaust valve guide 48 integrally fitted to the curved outer wall portion 34a of the exhaust port 34 in the cylinder head 14 is an exhaust valve opening facing the combustion chamber 20 of the exhaust port 34. Open and close 30.

The intake valve 46 and the exhaust valve 50 are biased upward by valve springs so that the head portions 46a and 50a thereof close the intake valve port 28 and the exhaust valve port 30 facing the combustion chamber 20, respectively. Stem ends 46b and 50b of the intake valve 46 and the exhaust valve 50 are pushed down by an intake rocker arm 56 and an exhaust rocker arm 58 that contact and oscillate with the intake cam and the exhaust cam of the camshaft 26, and the intake valve 46 and the exhaust valve 50 are opened at a predetermined timing. The exhaust valve 50 opens, the intake port 32 communicates with the combustion chamber 20, and the exhaust port 34 communicates with the combustion chamber 20, and intake and exhaust are performed at predetermined timings.

An inlet pipe 36 is connected to the upstream end of the intake port 32 of the internal combustion engine 10 via an insulator 60 to form a continuous intake passage 38. A throttle body 40 is connected to the upstream side of the inlet pipe 36. be done. The throttle body 40 has an intake passage 40a with a substantially circular cross section forming part of the intake passage 38 communicating with the combustion chamber 20 of the internal combustion engine 10, and the upstream side of the intake passage 40a is connected to an air cleaner device (not shown).

The throttle body 40 is rotatably supported in the throttle body 40 by a valve shaft, that is, a throttle valve shaft 40b which intersects the direction of flow of intake air in the intake passage 40a, that is, at right angles to the central axis of the intake passage 40a. It has a throttle valve 40c that can variably control the flow area of the intake passage 40a to open and close the intake passage 40a. The throttle valve 40c is of the butterfly type, and has a throttle valve shaft 40b and a disk-shaped valve body 40d that is fixed to the throttle valve shaft 40b and rotates integrally with the throttle valve shaft 40b.

The throttle valve 40c is rotatable counterclockwise in FIG. 1 in the valve opening direction by the driver's operation or the like. It is biased clockwise in the valve closing direction so as to be positioned at the fully closed position in contact with the inner wall surface. The opening direction and the closing direction of the throttle valve 40c may be opposite to each other.

In the internal combustion engine 10 as described above, the intake structure S is configured to give a tumble swirl flow of the fuel-air mixture in the combustion chamber 20 in order to obtain more favorable combustion in the combustion chamber 20, i.e., vertical rotation. ing. That is, the intake passage 38 is divided along the direction of intake air flow by a partition portion 62 leading from the inlet pipe 36 to the intake port 32, and is configured such that the passing intake air generates a tumble flow within the combustion chamber 20. It is partitioned into a tumble channel 64 and a main channel 66 excluding the tumble channel 64 . The tumble flow path 64 corresponds to the first intake passage, and the main flow path 66 corresponds to the second intake passage. Note that the tumble channel 64 may also be referred to as a secondary channel.

Furthermore, a partition 72 is provided in the tumble flow path 64 so as to continue mainly from the inlet pipe 36 to the intake port 32 . By providing the partition portion 72 , the tumble flow path 64 is partitioned into two intake passages 68 and 70 . One of the two intake passages 68 , 70 is the first tumble passage 68 and the other of them is the second tumble passage 70 . The first tumble flow path 68 corresponds to the third intake passage, and the second tumble flow path 70 corresponds to the fourth intake passage.

Here, the partition 62 that separates the tumble flow channel 64 and the main flow channel 66 is referred to as a main partition, and the partition 72 that separates the first tumble flow channel 68 and the second tumble flow channel 70 of the tumble flow channel 64 is called a secondary partition. It is called a partition. The main partition 62 extends like a plate in the direction of flow of intake air, and the sub-partition 72 also extends like a plate along the direction of the flow of intake air, for example, substantially parallel to the main partition 62 . The main partition 62 is provided so as to substantially bisect the intake passage 38 in the vertical direction, here so as to substantially extend on the central axis extending in the flow direction. Further, the sub-partition 72 is provided so as to substantially bisect the tumble flow path 64 in the vertical direction, here so as to substantially extend on the central axis of the tumble flow path 64 extending in the flow direction. As a result, a tumble flow path 64 and a main flow path 66 partitioned by the main partition 62 are formed in the intake passage 38, and a first tumble flow path 68 and a first A second tumble channel 70 is formed closer to the main channel 66 than the tumble channel 68, that is, positioned between the first tumble channel 68 and the main channel 66. As shown in FIG. Here, as described above, the main partition 62 extends so as to substantially bisect the intake passage 38 in the vertical direction, and the secondary partition 72 extends so as to substantially bisect the tumble flow passage 64 in the vertical direction. , the cross-sectional area of the main channel 66 is clearly greater than the cross-sectional area of the secondary tumble channel 70 . Note that the sub-partitions 72 may be provided so as to be biased, for example, in one of the vertical directions.

The cross-sectional area ratio of the main channel 66 and the tumble channel 64 (cross-sectional area of the main channel 66:cross-sectional area of the tumble channel 64) is preferably in the range of 1:1 to 3:1. The intake structure S of the internal combustion engine 10 is also designed within this range. Also, the ratio of the cross-sectional areas of the main channel 66, the second tumble channel 70, and the first tumble channel 68 (cross-sectional area of main channel 66: cross-sectional area of second tumble channel 70: first tumble channel 68) should be in the range of 6:4:2 to 9:1:2.

The lower portion of the intake passage 38 partitioned by the main partition 62 forms the tumble flow channel 64, the upper portion forms the main flow channel 66, and the lower portion of the tumble flow channel 64 partitioned by the secondary partition 72 forms the first tumble flow. Channel 68, the upper portion of which constitutes secondary tumble channel 70, is not limited herein to such a top-to-bottom arrangement. In this specification, the terms "top" and "bottom" of the intake passage 38 and the like refer to the direction from the crankshaft 17 to the cylinder head 14 or the cylinder head cover 24 in the direction of the cylinder axis C. , the direction opposite to this "upward" direction, that is, the direction from the cylinder head 14 side to the crankshaft 17 side is called the "downward" or "downward" direction, and the absolute "upward" or "downward" direction in space. does not mean As used herein, the "up" or "up" direction corresponds to the first direction, and the "down" or "down" direction corresponds to the second direction.

A tumble valve body 76 is connected to the upstream end of the inlet pipe 36 via an insulator 74 . The tumble valve body 76 has an intake passage 76a with a substantially circular cross section forming part of the intake passage 38, and the throttle body 40 is connected to the upstream end thereof.

The tumble valve body 76 is rotatably supported in the tumble valve body 76 by a valve shaft 76b which intersects the direction of intake air flow of the intake passage 76a, that is, at right angles to the central axis of the intake passage 76a. and a tumble valve 76c that can open and close the upper region of the intake passage 76a in cooperation with the partitions 62, 72. As shown in FIG. The tumble valve 76c is of the butterfly type, and has a valve shaft 76b and a substantially disk-shaped valve body 76d that is fixed to the valve shaft 76b and rotates together. In this manner, the tumble valve 76c is configured with the valve element 76d, which is a single valve member that rotates integrally with the valve shaft 76b. However, the valve shaft 76b of the tumble valve 76c is parallel to the throttle valve shaft 40b. The tumble valve 76c may also be called a tumble control valve, TCV, or the like, and corresponds to the intake control valve of the present invention.

　Here, Figs. 2 and 3 show a three-dimensional model M1 of the portion of the intake passage 38 on the downstream side of the throttle valve 40c. 2 is a perspective view of the three-dimensional model M1 from the downstream side, and FIG. 3 is a view of the three-dimensional model M1 from the horizontal direction (perpendicular to the vertical direction). 3 is a view of the three-dimensional model M1 viewed from a direction orthogonal to the valve axis 46c of the intake valve 46 and orthogonal to the extending direction of the main partition 62 and the extending direction of the sub-partition 72. FIG. . The three-dimensional model M1 represents the valve body 76d of the tumble valve 76c. 4 shows the valve body 76d of the tumble valve 76c. The valve body 76d, which is the single valve member of the tumble valve 76c, is substantially disk-shaped as described above, but the distal end portion 76t swung around the valve shaft 76b on the downstream side is substantially linear. As a result, the valve body 76d can be in a closed state with respect to the main partitioning portion 62 or can be in a closed state with respect to the sub-partitioning portion 72. As shown in FIG.

The main partition 62 continuously extends from a position immediately downstream of the tumble valve 76c to the intake port 32. Similarly, the sub-partition 72 continuously extends to the intake port 32 from a position immediately downstream of the tumble valve 76c. As is clear from FIG. 1, the valve stem 76b of the tumble valve 76c is positioned above the main partition 62. As shown in FIG. Therefore, naturally, the valve shaft 76b of the tumble valve 76c is positioned above the sub-partition portion 72. As shown in FIG. Additionally, the tumble valve 76c is a butterfly type valve. Therefore, the upstream edge 62a of the main partition 62 is located downstream of the upstream edge 72a of the sub-partition 72. As shown in FIG. Here, the upstream side of the sub-partition 72 extends into the tumble valve body 76, and the upstream edge 72a is formed in the tumble valve body 76, but is not limited to this. An intake structure S may be designed to be located in the pipe 36 . Note that the downstream edge 62b of the main partition 62 is located downstream of the downstream edge 72b of the sub-partition 72. As shown in FIG.

As shown in FIG. 1, the tumble valve body 76 is provided with a recess 77 that allows movement of the valve element 76d of the tumble valve 76c. The recessed portion 77 is provided in an upper wall portion 76u of a wall portion 76e of a tumble valve body 76, which is a wall portion defining and forming an intake passage 38, particularly an intake passage 76a. 1 and 3, the concave portion 77 has a substantially arc shape.

The tumble valve 76c configured as described above is configured to be able to open and close the main flow path 66, which is the second intake passage, and the second tumble flow path 70, which is the fourth intake passage. Here, the tumble valve 76c is provided so as not to affect the degree of opening of the first tumble flow path 68. As shown in FIG.

In FIG. 1, the valve body 76d of the tumble valve 76c is positioned so that the downstream side extends to the upstream edge 72a of the sub-partition portion 72. That is, in FIG. 1, the tumble valve 76c substantially closes the main flow path 66 and the secondary tumble flow path 70, naturally leaving the primary tumble flow path 68 open.

As shown in FIG. 1, the tumble valve 76c can be positioned at the first position P1 where the downstream tip 76t of the valve body 76d extends to the upstream edge 72a of the sub-partition 72. As shown in FIG. The tumble valve 76c has a first position P1 (solid line in FIG. 3), a fully open position PA (chain line in FIG. 3) in which the valve body 76d of the tumble valve 76c extends in the flow direction, and a downstream side of the valve body 76d. and a second position P2 (a chain double-dashed line in FIG. 3) extending to the upstream edge 62a of the main partition 62. As shown in FIG. With the tumble valve 76c at the fully open position PA, the tumble flow path 64 and the main flow path 66 are fully opened. With the tumble valve 76c in the first position P1, the primary tumble passage 66 and the secondary tumble passage 70 are substantially closed, as previously described with reference to FIG. remains open. With the tumble valve 76c in the second position P2, the main flow path 66 is substantially closed, leaving the second tumble flow path 70 in addition to the first tumble flow path 68 open. In this way, the tumble valve 76c is used at a plurality of degrees of opening, and the provision of the recess 77 allows the valve body 76d to be suitably positioned at the fully open position PA, the first position P1, and the second position P2. be positioned. Both when the tumble valve 76c is positioned at the first position P1 and when positioned at the second position P2, the inner wall surface 77a of the recess 77 and the portion of the valve body 76d facing it (hereinafter, arc-shaped portion) The inner wall surface 77a of the recess 77 is concavely curved so that a gap having substantially the same shape and substantially the same width is formed between the recess 76s (see FIG. 4). Note that the tumble valve 76c can be positioned at any other position. These positions of the tumble valve 76c are controlled by an ECU 80 described later based on the operating state of the internal combustion engine 10 here.

It should be noted that the valve body 76d of the tumble valve 76c is inclined when it is in the first position P1 shown in FIGS. At this time, the one end side half body 76f positioned below the valve body 76d of the tumble valve 76c in the intake flow direction F centered on the valve shaft 76b is positioned downstream of the one end side half body 76f. , forms an obtuse angle α with the corresponding sub-partition 72 . Also, at this time, the other end side half 76g positioned above the valve body 76d of the tumble valve 76c in the intake air flow direction F centered on the valve shaft 76b is positioned upstream and the other end side half 76g , forms an acute angle β with an upper wall portion 76u of the wall portions 76e of the corresponding recessed portion 77, that is, an inner wall surface 77a of the recessed portion 77, which is the intake passage wall surface. This angular relationship is also established when the valve body 76d of the tumble valve 76c is at the second position P2. An obtuse angle is formed with the corresponding main partition 62 and its downstream side.

A fuel injection valve 78 is provided in the internal combustion engine 10 . The fuel injection valve 78 is provided downstream of the throttle valve 40c and the tumble valve 76c. Here, the fuel injection valve 78 is provided in the inlet pipe 36 so as to face the main flow path 66 and is provided so as to inject fuel toward the intake port 32 . More specifically, fuel injection valve 78 is provided to inject fuel toward intake valve 46 via main flow path 66 . The fuel injection amount and the injection timing from the fuel injection valve 78 are controlled in association with the control of each of the throttle valve 40c and the tumble valve 76c.

Note that the throttle valve 40c is not limited to being electronically controlled, and may be a valve that is mechanically controlled by a throttle cable, for example, and the same applies to the tumble valve 76c. Further, in addition to the fuel injection valve 78, a further fuel injection valve may be provided. In this case, the further fuel injection valve supplies fuel to the intake passage downstream of the throttle valve 40c and upstream of the tumble valve 76c. may be provided to inject the If this additional fuel injector is provided, the amount of fuel injected from this additional fuel injector and its injection timing is similar to the amount of fuel injected from fuel injector 78 and its injection timing, or It may be controlled in association with the fuel injection amount from 78 and its injection timing.

An ECU (electronic control unit) 80 that controls the internal combustion engine 10 has a configuration as a so-called computer, and includes an intake control section 82 and a fuel injection control section 84 . The ECU 80 analyzes the operating state of the internal combustion engine 10 based on outputs from various sensors such as an engine rotation speed sensor and an engine load sensor, and controls the respective operations of the throttle valve 40c and the tumble valve 76c through the intake control unit 82. do. For example, the throttle valve 40c is controlled to an opening degree according to the accelerator operation by the driver. Further, the ECU 80 controls the operation of the fuel injection valve 78 by means of the fuel injection control section 84 based on the analyzed operating state of the internal combustion engine 10 . The ECU 80 stores programs and various data for these controls.

Here, the control of the tumble valve 76c will be explained in detail. For example, when the operating state of the internal combustion engine 10 is in the low load region, the ECU 80 positions the tumble valve 76c at the first position P1 so that the intake air is substantially drawn only from the first tumble flow path 68. control its operation. As a result, an intake air amount suitable for a low load region is ensured, and a tumble flow is formed in the combustion chamber 20 by intake air from the first tumble flow path 68 . Since the first tumble flow path 68 has a relatively small cross-sectional area, it is possible to increase the flow velocity even with an intake air amount suitable for a low load region, and to form a strong tumble flow. Here, when the operating state of the internal combustion engine 10 is in the low load region, the fuel injection from the fuel injection valve 78 is controlled so that the air-fuel ratio becomes lean, but by forming the tumble flow, effective combustion is achieved. can be generated.

Further, for example, when the operating state of the internal combustion engine 10 is in the middle load range, the ECU 80 controls the tumble valves so that the intake air is taken in from the first tumble flow path 68 and the second tumble flow path 70, that is, from the tumble flow path 64. 76c is controlled to be in the second position P2. As a result, the amount of intake air suitable for the medium load range is ensured, and the intake air from the first and second tumble passages 68 and 70 forms a tumble flow in the combustion chamber 20 . Since the intake air from the first and second tumble flow passages 68 and 70 forms the tumble flow, even in the medium load range where a larger amount of intake air is required than in the low load range, the necessary intake air amount is secured and strong A tumble flow can be formed. Here, when the operating state of the internal combustion engine 10 is in the medium load range, the fuel injection from the fuel injection valve 78 is controlled so that the air-fuel ratio becomes lean, but by forming the tumble flow, effective combustion is achieved. can be generated.

Further, for example, when the operating state of the internal combustion engine 10 is in the high load region, the ECU 80 causes the intake air to be taken in from the tumble flow path 64 including the first tumble flow path 68 and the second tumble flow path 70 and the main flow path 66. Then, the operation of the tumble valve 76c is controlled so that it is positioned at the fully open position PA. As a result, the amount of intake air suitable for the high load region is ensured, and the intake air from the first and second tumble flow paths 68 and 70 preferably creates a tumble flow in the combustion chamber 20, and even if not, a suitable cylinder flow is obtained. Achieve internal flow velocity. Here, when the operating state of the internal combustion engine 10 is in the high load region, the fuel injection from the fuel injection valve 78 is controlled so that the air-fuel ratio becomes stoichiometric, and furthermore, by realizing a suitable flow velocity in the cylinder, the effect is further increased. combustion can occur.

For example, when the operating state of the internal combustion engine 10 is in the high load region, the operation of the tumble valve 76c is controlled so that it is positioned at the fully open position PA, and intake air is taken in from the tumble flow path 64 and the main flow path 66. At this time, the intake structure S of the internal combustion engine 10 is designed to increase the amount of intake air by the intake air from the main flow path 66 and to more preferably secure the tumble performance by the intake air from the tumble flow path 64. It has further configurations and shapes. Further explanation is given below.

A confluence portion 86 is formed on the downstream side of the tumble flow channel 64 . The confluence portion 86 is provided at a point where the first tumble flow path 68 and the second tumble flow path 70 merge on the downstream side thereof. The tumble flow path 64 joins the main flow path 66 via the confluence portion 86 . The confluence portion 86 is formed in the cylinder head 14 . Here, the confluence portion 86 is formed as part of the intake port 32 .

Here, FIGS. 5 and 6 show a three-dimensional model M2 including the portion of the intake passage 38 on the downstream side of the throttle valve 40c and the tumble valve 76c and the exhaust passage of the exhaust port 34. FIG. FIG. 5 is a view of the three-dimensional model M2 from above, and FIG. 6 is a view of the three-dimensional model M2 from a direction orthogonal to the cylinder axis C and the direction of intake air flow. 7A shows a cross-sectional view of the solid model M2 along the line VIIA-VIIA in FIG. 6, and FIG. 7B shows a cross-sectional view of the solid model M2 along the line VIIB-VIIB in FIG. 7C shows a cross-sectional view of the solid model M2 at a position along the VIIC-VIIC line in FIG. 6, and FIG. 7D shows a cross-sectional view of the solid model M2 at a position along the VIID-VIID line in FIG. show. Line VIIA-VIIA in FIG. 6 passes near the upstream edge of the main partition 62, line VIIB-VIIB in FIG. line VIID--VIID in FIG. 6 passes near the downstream edge of the main partition 62. FIG. All of these lines VIIA-VIIA to VIID-VIID are parallel to the cylinder axis C in FIG.

7A, 7B and 7C, the first tumble channel 68 and the second tumble channel 70 have generally the same shape and size. Thus, each of the first tumble flow path 68 and the second tumble flow path 70 smoothly extends from the upstream side to the downstream side without significantly changing its shape or size in the intake air flow direction. The first tumble flow path 68 and the second tumble flow path 70 are connected to the confluence portion 86 . The confluence portion 86 is connected to the main flow path 66 on the downstream side of the downstream edge 62b of the downstream end of the main partition portion 62 (see FIGS. 1 and 6). With this configuration, the first tumble flow path 68 and the second tumble flow path 70 are connected to the main flow path 66 via the confluence portion 86 on the downstream side of the downstream edge 72b of the sub-partition portion 72 . Therefore, the intake air passing through the first tumble flow path 68 and the second tumble flow path 70 of the tumble flow path 64 can have strong directivity.

In FIG. 6, the line L1 defined to extend in the intake flow direction at the confluence portion 86 intersects the cylinder axis C at an angle θ1 close to a right angle. line L2 intersects the cylinder axis C at an angle .theta.2 smaller than the angle .theta.1. In this way, the confluence portion 86 is partitioned so that the intake air from the tumble flow passage 64 via the confluence portion 86 flows into the combustion chamber 20 at a smaller entrance angle than the intake air from the main flow passage 66. . With this configuration, the intake air passing through the tumble flow path 64 can be introduced into the combustion chamber 20 while maintaining strong directivity, and a strong tumble flow can be generated in the combustion chamber 20, for example. The term "advance angle" as used herein refers to the angle at which the intake air flowing into the combustion chamber 20 flows into the combustion chamber 20. For example, when viewed from a direction perpendicular to the cylinder axis C and the direction of intake air flow, as shown in FIG. , the larger the angle formed with the cylinder axis C, the smaller the approach angle.

1, 3 and 6, the tumble channel 64 is defined to have a downwardly convex curved shape, and the main channel 66 has an upwardly convex curved shape. It is partitioned as follows. With this configuration, as described above, it is possible to guide the intake air from the tumble flow path 64 to the combustion chamber 20 at a smaller entrance angle, and to more effectively direct the intake air from the main flow path 66 to the combustion chamber 20. be able to guide.

FIG. 7C shows that the first tumble flow path 68 and the second tumble flow path 70 communicate with the upstream end of the confluence portion 86 . Here, for reference, FIG. 1 shows one side TA1 of the cross section in the imaginary plane. The side TA1 of the upstream end 86u of the merging portion 86 is longer than the vertical length of the cross section 68A of the first tumble flow channel 68 and the vertical length of the cross section 70A of the second tumble flow channel 70, respectively. is clearly long. In this way, the cross-sectional area of each of the first tumble flow path 68 and the second tumble flow path 70 (areas S1 and S2 in FIG. 7C) is equal to the cross-sectional area S3 of the upstream end 86u of the merging portion 86 (by side TA1). The confluence portion 86 is partitioned so as to be smaller than the cross-sectional area of which a part is partitioned (S1<S3, S2<S3). With this configuration, the intake air from the first tumble flow path 68 and the intake air from the second tumble flow path 70 can preferably flow into the confluence portion 86 . More specifically, when the tumble valve 76c is at the second position P2 and intake air is flowing through the first tumble flow path 68 and the second tumble flow path 70, the cross-sectional area of the confluence portion 86 is Since the cross-sectional area is larger than that of each of the second tumble flow paths 70, the amount of intake air is less likely to be restricted at the confluence portion 86, and the amount of intake air suitable for the operating range of the middle load range can be ensured.

Also, for example, side TA2 in FIG. 7D is shorter than side TA1 in FIG. 7C. That is, toward the downstream side, the cross-sectional area of the confluence portion 86 of the tumble flow channel 64 tends to be smaller at the cross-sectional location in FIG. 7D than at the side TA1 in FIG. 7C, for example. Thus, in the internal combustion engine 10, the confluence portion 86 is sectioned so as to generally taper from the upstream end portion of the confluence portion 86 toward the downstream side. With this configuration, the upstream end 86u of the merging portion 86 is larger than the sum of the cross-sectional areas of the first tumble flow path 68 and the second tumble flow path 70 (for example, the sum of the area S1 of the cross section 68A and the area S2 of the cross section 70A). The area (cross-sectional area) in the cross section orthogonal to the flow direction on the downstream side becomes smaller. As a result, when the intake air from the first tumble flow path 68 and the intake air from the second tumble flow path 70 merge at the confluence portion 86 and flow into the main flow path 66, the flow velocity of the intake air can be kept high. Become. Therefore, the intake air from the tumble channel 64 can flow into the combustion chamber 20 at a high flow velocity and preferably form a tumble flow. It should be noted that the cross-sectional area perpendicular to the flow direction on the downstream side of the upstream end of the confluence portion 86 cannot be made smaller than the sum of the cross-sectional areas of the first tumble flow channel 68 and the second tumble flow channel 70. , may be realized by means other than tapering.

Now, as mentioned above, the tumble valve 76c can be positioned in the first position P1 and the second position P2. When positioned in any of them, at least one intake passage is closed and the intake air from the remaining intake passages tries to positively generate a tumble flow. However, in order to increase the degree of blockage of at least one intake passage in the tumble valve 76c when the valve is closed, the design accuracy of the valve body 76d may be improved or the wall surface defining the intake passage 76a of the tumble valve body 76 may be improved. You need to improve your accuracy. Therefore, in this embodiment, the tumble valve 76c is positioned at the first position P1 to close the main flow path 66, which is the second intake passage, and the second tumble flow path 70, which is the fourth intake passage. At this time, a gap (first gap) G1 is actively formed between the sub-partition 72 and the valve body 76d, and extends to the side opposite to the sub-partition 72 of the tumble valve 76c, that is, to the upper side. A clearance (second clearance) G2 is formed between the wall surface defining the intake passage 76a, that is, the intake passage wall surface, and the valve body 76d of the tumble valve 76c. In other words, at that time, the upstream end 72a of the sub-partitioning portion 72 is separated from the facing tip portion 76t of the valve body 76d by a predetermined distance (first predetermined distance) corresponding to the first gap portion G1, and the tumble valve 76c The wall surface defining the upwardly extending air intake passage 76a is separated from the opposite edges of the valve body 76d of the tumble valve 76c, that is, the arcuate portion 76s by a predetermined distance (second predetermined distance) corresponding to the second clearance G2. Here, the wall surface defining the intake passage 76a extending above the tumble valve 76c is the upper wall portion 76u of the wall portion 76e of the tumble valve body 76, that is, the inner wall surface 77a of the recess 77. 1 and 3, the valve body 76d of the tumble valve 76c is inclined. Located downstream of G2.

Each of the first gap G1 and the second gap G2 has a gap width equal to or less than the thickness of the main partition 62. The thickness of the main partition 62 is preferably the average thickness of the main partition 62 extending in the intake air flow direction. Specifically, each of the first gap G1 and the second gap G2 preferably has a gap width of 3 mm or less (0<gap width≦3 mm), more preferably 2 mm or less (0<gap width≦3 mm). 2 mm). Here, the sub-partitions 72 are also formed to have approximately the same thickness as the main partitions 62 . That is, in the present embodiment, each of the first gap G1 and the second gap G2 has a gap width equal to or less than the thickness of the sub-partition 72 . The first gap G1 has a maximum width in FIGS. 1 and 3, and is formed so that the width of the gap becomes smaller as it progresses to the left and right (the direction perpendicular to the paper surface in FIGS. 1 and 3). Good. Similarly, the second gap G2 has a maximum width in FIGS. 1 and 3, and is preferably formed so that the width of the gap decreases as it progresses to the left and right. These gaps G1 and G2 are designed to realize the flow of intake air (for example, see arrows in FIG. 10), which will be described later. Here, in FIGS. 1 and 3, the gaps G1 and G2 have a gap width of about 2 mm, but the width is not limited to this.

Before explaining the effect of providing the gaps G1 and G2, related phenomena will be explained below with reference to FIGS. 8 and 9. FIG. Note that the description similar to the description below based on FIGS. 8 and 9 is described in detail in JP-A-2019-23459.

In FIG. 8, the intake passage 100 is provided with a partition portion 106 that separates the tumble flow passage 102 and the main flow passage 104, and the butterfly valve 108 is provided upstream of the partition portion 106, and the butterfly valve 108 gradually opens. FIG. 4 is a diagram schematically showing the flow of intake air when the valve is open (when it is in a slightly open state). FIG. 9 is a diagram mainly showing the pressure on the downstream side when the butterfly valve 108 shown in FIG. 8 is gradually opened.

The butterfly valve 108 is rotatable in the counterclockwise direction R in FIG. 8 in the valve opening direction. It is biased clockwise in the valve closing direction so that the other end half body 108c, which rotates while contacting the inner wall surface 110 forming the partition, is positioned at the fully closed position in contact with the inner wall surface 110. As shown in FIG.

One end side half 108b of the butterfly valve 108 in the fully closed state has an obtuse contact angle with the inner wall surface 110 of the intake passage 100 on the downstream side in the intake air flow direction F, and the other end side half 108c has an obtuse contact angle with the intake air flow direction F. The contact angle of the inner wall surface 110 of the intake passage 100 on the downstream side in the direction F is acute. In other words, the butterfly valve 108 is inclined, its one end half 108b is positioned downstream of the intake passage 100 with respect to the valve shaft 108d, and the other end half 108c of the butterfly valve 108 is Located upstream of the intake passage 100 . When the butterfly valve 108 changes from the fully closed position in such a state to the gradually opened position as shown in FIG. Through the gap (hereinafter referred to as the obtuse angle side gap) 110a formed between the inner wall surface 110 and the gap (hereinafter referred to as the acute angle side gap) 110b formed between the other end side half 108c and the inner wall surface 110 , flows downstream. At this time, as shown in FIGS. 8 and 9, the angle α1 between the one end half 108b of the butterfly valve 108 and the inner wall surface 110 of the intake passage 100 is an obtuse angle. The angle β1 formed between the passage 100 and the inner wall surface 110 is an acute angle.

At this time, as shown in FIG. 9, a strong negative pressure is generated in the region 112 immediately downstream of the obtuse-angle side gap 110a and the acute-angle side gap 110b (black portion in FIG. 9), and the valve shaft 108d of the butterfly valve 108 is A wide negative pressure area 114 (dotted hatched area in FIG. 9) is generated in the downstream range of the butterfly valve 108 including. That is, as shown in FIG. 9, the portion of the intake passage 100 on the downstream side of the butterfly valve 108 is separated along the intake air flow direction F by the partition portion 106 having a surface substantially parallel to the valve shaft 108d of the butterfly valve 108. , divided into two channels 102 and 104 with large and small cross-sectional areas, the channel 104 with the larger cross-sectional area is downstream of the other end half 108c, and the channel 102 with the smaller cross-sectional area is located downstream. If arranged on the downstream side of the one end side half 108b, when the butterfly valve 108 is gradually opened, the momentum of the intake air passing through the butterfly valve 108 and flowing toward the flow path 104 having a large cross-sectional area tends to weaken, and the momentum of the lost cross-sectional area decreases. The intake air flowing through the large flow path 104 is attracted by the negative pressure generated in the immediately downstream portions 112 (black portions in FIG. 9) of each end of the one end side half body 108b and the other end side half body 108c of the butterfly valve 108. , backflow upstream. The backflowing intake air is attracted by the negative pressure generated in the direct downstream portion 112 of the first end half 108b on the side of the flow path 102 with the small cross-sectional area, and then passes through the butterfly valve 108 together with the intake air with the small cross-sectional area. The intake air flowing into and through the channel 102 increases.

Therefore, the channel 104 with a large cross-sectional area is used as the main channel, and the channel 102 with a small cross-sectional area is used as the tumble channel. , the intake air that has once flowed into the main flow path 104 can be led to the tumble flow path 102 . That is, by setting the cross-sectional area of the main channel 104 to be larger than the cross-sectional area of the tumble channel 102, the intake air flowing through the tumble channel 102 can be strengthened.

Furthermore, in a cross-sectional view along the central axis X of the intake passage 100 at right angles to the valve shaft 108d of the butterfly valve 108, the one end half 108b of the fully closed butterfly valve 108 is in contact with the inner wall surface 110 at an obtuse angle, The other end half 108c of the butterfly valve 108 is in contact with the inner wall surface 110 at an acute angle, the tumble flow path 102 is located downstream of the one end half 108b, and the main flow path is downstream of the other end half 108c. 104 is located. In this manner, one end side half 108b of butterfly valve 108 when fully closed is arranged so as to be in contact with inner wall surface 110 on the downstream side at an obtuse angle. , is inclined from the main flow path 104 toward the tumble flow path 102, and when the butterfly valve 108 is gradually opened or the like, the reverse flow of the main flow path 104 is easily led to the tumble flow path 102 side, and the partition portion 106 is inclined toward one end side half. body 108b, and in the direction of intake air flow F, the distance from one end half 108b to the partition 106 is less than the distance from the other end half 108c to the partition 106; Therefore, the intake air that has passed through the one end half 108b easily flows into the tumble flow path 102, and the amount of intake air that flows into the tumble flow path 102 can be increased.

Here, we return to the description of the above embodiment of the present invention. As mentioned above, when the tumble valve 76c is in the first position P1 shown in FIG. The one end side half body 76f located on the downstream side forms an obtuse angle α with the corresponding sub-partition 72 on the downstream side thereof, and the other end side half body 76g located above the valve body 76d of the tumble valve 76c , upstream and forms an acute angle β with the wall 76e of the corresponding recess 77 on its downstream side. The cross-sectional area of the main flow path 66 is larger than the cross-sectional area of the second tumble flow path 70, and the second tumble flow path 70 is arranged downstream of the one end half body 76f of the valve element 76d of the tumble valve 76c. A main flow path 66 is arranged downstream of the other end half 76g of the body 76d. Therefore, the butterfly valve 108, the tumble flow path 102 and the main flow path 104 in FIG. 8 can be associated with the tumble valve 76c, the second tumble flow path 70 and the main flow path 66 in this embodiment. Therefore, by designing the tumble valve 76c so as to form the first gap G1 and the second gap G2 as described above, the intake structure S for the internal combustion engine of the present embodiment can be constructed based on FIG. The inspiratory flow described can be achieved.

As shown in FIG. 10, according to the intake structure S of the internal combustion engine 10 of FIG. 1, when the tumble valve 76c is at the first position P1, the first gap G1 and the second gap G2 is formed as The flow of intake air at this time is schematically indicated by arrows in FIG. Although the intake air that has passed through the second gap G2 can once flow toward the main flow path 66, part or preferably all of it returns to the second tumble flow path 70, together with the intake air that has passed through the first gap G1. , flow through the second tumble channel 70 . In this way, the intake air that has flowed downstream through the tumble valve 76c in the first position P1 enters the second tumble flow path 70 and eventually flows into the tumble flow path 64. As shown in FIG.

In the intake structure S of the internal combustion engine 10 described above, when the tumble valve 76c is positioned at the first position P1, the first gap G1 is formed between the sub-partition 72 and the valve body 76d of the tumble valve 76c. In addition, a second clearance G2 is formed between the wall surface 77a defining the upper intake passage of the tumble valve 76c and the valve body 76d. As a result, as described above, when the tumble valve 76c is controlled to the first position P1, in addition to the first tumble flow path 68 that is mainly opened, the flow of intake air to the second tumble flow path 70 is encouraged. , thus promoting the flow of intake air into the tumble flow path 64 containing them, thus preferably enhancing the tumble flow in the intake air through the first tumble flow path 68 rather than impeding the formation of the tumble flow. can be done. Therefore, the tumble performance can be secured favorably.

Also, in this way, the tumble valve 76c is not designed to increase the degree of blockage, but is designed to form the first and second gaps G1 and G2. Since the first and second gaps G1, G2 may have a certain width as described above, designing the tumble valve 76c to form the gaps G1, G2 in this way does not allow the valve to close. This is easier than increasing the degree of closure of the tumble valve 76c. Therefore, it becomes possible to relax the clearance management of the tumble valve 76c.

Therefore, according to the intake structure S of the internal combustion engine 10, it is possible to relax the clearance management of the tumble valve 76c and ensure the tumble performance.

When the tumble valve 76c is thus controlled to the first position, the intake air that has flowed through the second tumble flow path 70 is transferred to the first tumble flow path 68 whose main purpose is to flow the intake air at that time. It merges with the intake air at the junction 86 and is taken into the combustion chamber 20 . Therefore, at this time, the intake air from the tumble flow path 64 including the intake air flowing through the second tumble flow path 70 can be given a strong directivity, and the tumble flow in the combustion chamber 20 can be favorably strengthened. Tumble performance can be further secured.

When the tumble valve 76c is in the second position P2, the tumble valve 76c tilts in the same manner as when it is in the first position P1, and the main partition 62 and the valve body 76d A clearance is formed between the valve body 76d of the tumble valve 76c and the wall surface defining the intake passage 76a extending upward from the tumble valve 76c. At this time, the intake air that has passed through the tumble valve 76c can flow into the main flow path 66. Since it is possible to give strong directivity to the , it is possible to obtain sufficient tumble performance as a whole.

In the intake structure S of the internal combustion engine 10, the main partition 62 partitions the tumble flow path 64 and the main flow path 66, and the sub-partitions partition the tumble flow path 64 into first and second tumble flow paths 68 and 70. 72 are provided. According to the intake structure S, the main flow path 66 and the tumble flow path 64 are provided, and the tumble flow path 64 can be divided into the first tumble flow path 68 and the second tumble flow path 70 . Therefore, it is possible to use any one or all of them depending on the operating state of the internal combustion engine to secure the intake air amount according to the operating state.

The number of sub-partitions is not limited to one, and may be plural. By providing a plurality of sub-partitions in the tumble flow path 64, the tumble flow path 64 can be divided into a third intake passage corresponding to the first tumble flow passage 68 and a fourth intake passage corresponding to the second tumble flow passage 70. It becomes possible to divide into three or more intake passages, ie, intake passage sections, including the . The plurality of divided intake passage portions should preferably be connected to the main flow passage 66 via the confluence portion 86 and then to the combustion chamber 20, similar to the first and second tumble flow passages 68 and 70 described above. In this case, the plurality of sub-partitions may be provided in the tumble flow channel 64 separately from each other in the vertical direction. At this time, a tumble valve may be provided so as to positively utilize the reverse flow phenomenon of the intake air to the tumble flow path described with reference to FIGS. 8 to 10 .

Also, various members that define the intake passage of the internal combustion engine 10, particularly the intake passage on the downstream side of the throttle valve 40c, are preferably manufactured mainly by casting. As a result, it is possible to realize various shapes such as a downwardly convex tumble channel 64 and an upwardly convex main channel 66 . It should be noted that the present disclosure does not exclude the production of the member that defines the intake passage by a method other than casting.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to them. Various substitutions and changes can be made without departing from the spirit and scope of the invention as defined by the claims of this application.

In the intake structure of the internal combustion engine of the above embodiment, the second tumble flow path is formed above the first tumble flow path, and the main flow path is provided above the tumble flow path including these. However, the second tumble channel may be formed below the first tumble channel, and the main channel may be provided below the tumble channel including these. However, at this time, the tumble valve 76c is preferably turned upside down in the drawing corresponding to FIG.

10... internal combustion engine, 12... cylinder block, 14... cylinder head, 15... piston
20... Combustion chamber, 28... Intake valve port, 30... Exhaust valve port, 32... Intake port, 34... Exhaust port
38... Intake passage, 40... Throttle body, 46... Intake valve, 50... Exhaust valve
62... Partition (main partition), 64... Tumble passage (first intake passage)
66...Main passage (second intake passage), 68...First tumble passage (third intake passage)
70...Second tumble flow path (fourth intake passage), 72...Partition (secondary partition)
76...Tumble valve body, 76c...Tumble valve (intake control valve), 86...Joining portion, S...Intake structure G1...First clearance, G2...Second clearance

Claims (10)

The intake passage (38) communicating with the combustion chamber (20) of the internal combustion engine (10) is composed of a first intake passage (64) serving as a tumble flow path for generating a tumble flow in the combustion chamber (20); a main partition (62) that separates two intake passages (66);
A sub-partition (72) provided in the first intake passage (64) to form a third intake passage (68) and a fourth intake passage (70), wherein the fourth intake passage (70 ) is a sub-partition ( 72) and
an intake control valve (76c) provided upstream of the main partition (62),
When the intake control valve (76c) is in a state of closing the second intake passage (66) and the fourth intake passage (70), the auxiliary partition (72) and the valve body of the intake control valve (76c) (76d) and a first gap (G1) is formed between the intake passage wall surface (77a) of the intake control valve (76c) and the valve An intake structure (S) for an internal combustion engine (10), characterized in that a second gap (G2) is formed between the body (76d) and the body (76d). When the direction of the cylinder axis (C) from the crankshaft (17) side to the cylinder head (14) side is defined as the first direction, the main partition (62) defines the intake passage (38) as the first intake passage (38). partitioning into a passageway (64) and a second intake passageway (66) on the first direction side of the first intake passageway (64);
The sub-partition (72) includes the first intake passage (64), the third intake passage (68), and the fourth intake passage (68) on the first direction side of the third intake passage (68). 70). An intake structure (S) for an internal combustion engine (10) according to claim 1, characterized in that it is provided to form a. 3. The internal combustion engine according to claim 1, wherein the first gap (G1) is located downstream of the second gap (G2) in the intake flow direction (F). (10) intake structure (S). Each of the first gap (G1) and the second gap (G2) has a gap width equal to or less than the thickness of the main partition (62). An intake structure (S) for an internal combustion engine (10) according to any one of Claims 1 to 3. A confluence portion (86) where the third intake passageway (68) and the fourth intake passageway (70) merge, and the first intake passageway (64) is connected to the first intake passageway (64) via the confluence portion (86). 2 The confluence portion (86) that merges with the intake passage (66)
An intake structure (S) for an internal combustion engine (10) according to any one of claims 1 to 4, further comprising: Flow downstream of the upstream end (86u) of the junction (86) relative to the sum of the cross-sectional areas (S1, S2) of the third intake passage (68) and the fourth intake passage (70) 6. An intake structure (S) for an internal combustion engine (10) according to claim 5, wherein said merging portion (86) is formed so as to have a smaller area in a cross section perpendicular to the direction. The intake air from the first intake passage (64) through the junction (86) flows into the combustion chamber (20) at a smaller entrance angle than the intake air from the second intake passage (66). 7. An intake structure (S) for an internal combustion engine (10) according to claim 5 or 6, characterized in that said confluence (86) is partitioned. The intake control valve (76c) is configured to be able to open and close the second intake passage (66) and the fourth intake passage (70). A first position (P1) that closes the intake passage (70), a second position (P2) that closes the second intake passage (66) and opens the fourth intake passage (70), and a fully open position (PA). An intake structure (S) for an internal combustion engine (10) according to any one of claims 1 to 7, characterized in that it comprises: The intake control valve (76c) includes a single valve member (76d) that rotates integrally with the valve shaft (76b),
9. A recess (77) for allowing movement of the valve member (76d) is provided in a wall section defining the intake passage (38). 3. An intake structure (S) for an internal combustion engine according to the above paragraph. When the intake control valve (76c) is in a state of closing the second intake passage (66) and the fourth intake passage (70), in the intake flow direction (F) about the valve shaft (76b), The one end half (76f) of the valve member (76d) of the intake control valve (76c) is positioned downstream, and the secondary partition (72) is positioned downstream of the one end half (76f). Forming an obtuse angle (α), the other end side half (76g) of the valve member (76d) is positioned upstream, and the wall of the recess (77) is positioned downstream of the other end side half (76g). 10. An intake structure (S) for an internal combustion engine according to claim 9, characterized in that it forms an acute angle ([beta]) with the portion (76e).

Images