WO2022176860A1

WO2022176860A1 - Intake structure for internal combustion engine

Info

Publication number: WO2022176860A1
Application number: PCT/JP2022/006004
Authority: WO
Inventors: 裕高河津; 加代子武市; 治江水
Original assignee: 本田技研工業株式会社
Priority date: 2021-02-18
Filing date: 2022-02-15
Publication date: 2022-08-25
Also published as: JPWO2022176860A1; JP7403707B2

Abstract

The purpose of the present disclosure is to provide a configuration that makes it possible for a plurality of intakes that are split by a dividing section and flow into a combustion chamber of an internal combustion engine to be drawn into the combustion chamber more effectively. An intake structure S for an internal combustion engine according to one embodiment of the present invention comprises: a dividing section 62 that is configured so as to split an intake channel 38 into a plurality of channels and that separates a first intake channel 64 and a second intake channel 66 within the intake channel; and a downstream-side wall section 82 that is disposed downstream of the dividing section 62 so that the flow of intake from the second intake channel 66 into a combustion chamber 20 is directed in a direction that intersects the direction of flow of intake from the first intake channel 64 into the combustion chamber 20.

Description

Intake structure of internal combustion engine

The present invention relates to an intake structure for an internal combustion engine that includes partitions that divide 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. Note that the tumble valve is a valve that can also be called an intake distribution valve or an intake control valve, and may not be provided in an internal combustion engine provided with the partition section (see, for example, Patent Document 2).

Japanese Patent No. 6714764 Japanese Patent No. 6439070

By the way, when the operating state of the internal combustion engine is in a predetermined operating state such as a high load, for example, the throttle valve or both the throttle valve and the tumble valve are fully opened or nearly so so as to increase the efficiency of intake air into the combustion chamber. be done. In recent years, there has been a growing demand for improved fuel efficiency, and it is desired to improve output while more effectively producing lean combustion even in the above-described predetermined operating conditions. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to more effectively direct intake air flowing through a plurality of passages divided by the partitions into a combustion chamber in an internal combustion engine having an intake passage divided by the partitions. To provide a configuration that enables inhalation.

In order to achieve the above object, one aspect of the present invention is
a partition configured to divide an intake passage into a plurality of sections, the partition separating a first intake passage and a second intake passage in the intake passage;
It is provided on the downstream side of the partition so as to direct the flow of intake air from the second intake passage to the combustion chamber in a direction that intersects the flow direction of intake air from the first intake passage to the combustion chamber. and a downstream side wall portion.

According to the above configuration, the intake air flowing from the second intake passage to the combustion chamber is less likely to be affected by the intake air flowing from the first intake passage to the combustion chamber. Therefore, it becomes possible to more effectively draw the intake air flowing through the plurality of passages divided by the partition into the combustion chamber.

Preferably, when a direction from the crankshaft side to the cylinder head side in the cylinder axial direction is defined as a first direction, and a direction opposite to the first direction is defined as a second direction, the first intake passage is defined as the above-mentioned The partition extends into the intake passage so as to define a second intake passage on the second direction side, and the downstream side wall portion is the first direction side. With this configuration, the intake air from the second intake passage is less likely to be affected by the intake air from the first intake passage, and the intake air from the second intake passage can be effectively promoted to the combustion chamber side.

Preferably, at least part of the downstream side wall portion extends along the valve axis of the intake valve. With this configuration, it is possible to smoothly direct the intake air from the second intake passage toward the combustion chamber.

Preferably, when viewed from a direction perpendicular to the extending direction of the partition and perpendicular to the valve axis of the intake valve, at least a part of the downstream side wall is positioned closer to the exhaust than the valve axis of the intake valve. and is provided on the valve axis side of an imaginary line passing through an intermediate point between the exhaust side end of the opening of the intake valve and the valve axis and parallel to the valve axis. . This arrangement makes it possible to more effectively direct the intake air from the second intake passage into the combustion chamber, more preferably to the intake side of the combustion chamber.

Preferably, a central axis in the flow direction of the outlet portion of the first intake passage, which is defined at the downstream edge of the partition portion, extends so as to pass through an opening range of the intake valve on the exhaust side when the intake valve is opened. . With this configuration, the intake air from the first intake passage can be guided more effectively and directly to the combustion chamber while suppressing flow resistance.

Preferably, when a direction from the crankshaft side to the cylinder head side in the cylinder axial direction is defined as a first direction and a direction opposite to the first direction is defined as a second direction, the downstream side wall portion A section is formed so that the flow of intake air from the second intake passage to the combustion chamber is directed from the first direction side to the second direction side of the flow of intake air from the first intake passage to the combustion chamber. . This configuration makes it possible to more effectively introduce the intake air from the second intake passage into the combustion chamber.

Preferably, the internal combustion engine includes a single intake valve, the partition is formed so that the second intake passage extends along both sides of the first intake passage in the intake air flow direction, and the downstream side wall portion is , are provided downstream of the second intake passage so as to be located on both sides in the flow direction of the intake air of the intake valve. This configuration makes it possible to more effectively reduce the influence of the intake air from the first intake passage on the intake air from the second intake passage.

Preferably, the downstream side wall portion directs the flow of intake air from the second intake passage to the combustion chamber from the side of the flow of intake air from the first intake passage to the combustion chamber of the opening of the intake valve. It is provided so as to face the opening on the intake side. With this configuration, it is possible to more effectively reduce the influence of the intake air from the first intake passage on the intake air from the second intake passage.

Preferably, the downstream side wall portion has a curvature smaller than the average curvature of the wall portion defining the intake passage. With this configuration, the direction of flow of intake air from the second intake passage can be changed more effectively at the downstream side wall portion.

According to the above aspect of the present invention, since it has the above configuration, in an internal combustion engine configured such that the intake passage is divided by the partition, the intake air flowing through the plurality of passages divided by the partition is It becomes possible to inhale into the combustion chamber more effectively.

FIG. 1 is a schematic configuration diagram of the essential parts of an internal combustion engine according to one embodiment of the present invention. 2A is a cross-sectional view of the internal combustion engine of FIG. 1 and is a cross-sectional view of the internal combustion engine taken along line IIA-IIA of FIG. 1. FIG. 2B is a cross-sectional view of the internal combustion engine of FIG. 1, and is a cross-sectional view of the internal combustion engine taken along line IIB-IIB of FIG. 2C is a cross-sectional view of the internal combustion engine of FIG. 1, taken along line IIC-IIC of FIG. 1. FIG. FIG. 3 is a diagram showing a three-dimensional model of a downstream portion of an intake passage of the internal combustion engine of FIG. 1, and is a perspective view from above. FIG. 4 is a view of the three-dimensional model of FIG. 3 viewed from the left and right. FIG. 5 is a diagram of the three-dimensional model of FIG. 3 as seen from below. 6A is a cross-sectional view of the three-dimensional model of FIG. 3, and a cross-sectional view along line VIA-VIA of FIG. 4. FIG. 6B is a cross-sectional view of the three-dimensional model in FIG. 3, and a cross-sectional view along line VIB-VIB in FIG. 6C is a cross-sectional view of the three-dimensional model of FIG. 3, and is a cross-sectional view along line VIC-VIC of FIG. 4. FIG. FIG. 7 is an enlarged cross-sectional view of a portion of the internal combustion engine of FIG. 1, enlarging the downstream side of the intake passage. 8A is a schematic diagram of a downstream portion of an intake passage of the internal combustion engine of FIG. 1, viewed from above. FIG. FIG. 8B is a schematic diagram of the downstream side portion of the intake passage of the internal combustion engine of FIG. 1, viewed from the left-right direction. 9 is a schematic cross-sectional view of the internal combustion engine of FIG. 1. FIG. FIG. 10A is a computer simulation result for the internal combustion engine of FIG. FIG. 10B is a computer simulation result for a comparative internal combustion engine. FIG. 11A is a schematic diagram of the downstream portion of the intake passage of the comparative internal combustion engine, viewed from above. FIG. 11B is a schematic diagram of the downstream side portion of the intake passage of the comparative internal combustion engine, viewed from the left-right direction. 4 is a graph showing the results of measuring the flow rate of intake air flowing through the intake port by computer simulation. 4 is a graph showing the results of measuring the flow velocity of intake air in a cylinder of an internal combustion engine by computer simulation;

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 the cylinder head 14 side of the internal combustion engine 10 along the axis (cylinder axis) C of the cylinder bores 12b of the cylinder block 12 of the internal combustion engine 10. FIG. Although the internal combustion engine 10 is a single-cylinder engine, the internal combustion engine to which the present invention is applied may be a so-called multi-cylinder engine having multiple cylinders.

A piston 16 that reciprocates in the cylinder bore 12b of the cylinder block 12 is connected by a connecting rod 18 to a crankpin of a crankshaft (not shown) of a crankcase (not shown). A combustion chamber 20 is formed between the top surface 16a of the piston 16 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 16a. 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 connected to a cam (not shown) provided on one side of the crankcase, cylinder block 12, and cylinder head 14 in the crankshaft direction. It is installed between the camshaft 26 and the crankshaft through the chain chamber, and the camshaft 26 rotates in synchronism with the crankshaft at half the rotation speed. A spark plug 27 (see FIG. 7) 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 opening 28 and the exhaust valve opening 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 throttle valve shaft 40b that intersects the central axis of the intake passage 40a at right angles to the flow direction of intake air in the intake passage 40a. It has a throttle valve 40c that can variably control the flow passage area of the air 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.

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 passage 64 and a main passage 66 excluding the tumble passage 64. - 特許庁The tumble passage 64 corresponds to the first intake passage, and the main passage 66 corresponds to the second intake passage. Note that the tumble passage 64 may also be referred to as a secondary passage.

The lower part of the intake passage 38 partitioned by the partition part 62 is the tumble passage 64, and the upper part is the main passage 66, but in this specification they are not limited to their vertical arrangement. In this specification, the terms "top" and "bottom" with respect to the intake passage 38 and the like refer to the direction from the crankshaft side to the cylinder head 14 or the cylinder head cover 24 side in the direction of the cylinder axis C. The direction opposite to this "up" direction, that is, the direction from the cylinder head 14 side to the crankshaft side is called the "down" or "down" direction, and is the absolute "up" or "down" direction in space. Not meaning. The "up" or "up" direction corresponds to the first direction, and the "down" or "down" direction corresponds to the second direction.

In the inlet pipe 36, an intake distribution valve 68 is provided downstream of the throttle valve 40c and upstream of the partition portion 62. The intake air distribution valve 68 is a valve that can also be called a tumble valve or an intake control valve. The intake air distribution valve 68 is a valve whose base end rotating shaft 68a is rotatably supported by the inlet pipe 36 in the vicinity of the upstream end edge of the partition part 62, and whose tip facing the intake upstream side is rotatable up and down. , is rotated about the rotation axis 68a. The intake air distribution valve 68 rotates with its tip directed toward the upstream throttle valve 40c to divide the intake air downstream from the throttle valve 40c vertically and change the ratio of the intake air flowing through the tumble passage 64 and the main passage 66. can do.

The partition portion 62 continuously extends from a position immediately downstream of the intake distribution valve 68 to the intake port 32 . By closing the intake air distribution valve 68 as shown in FIG. 1, the main passage 66 is substantially completely closed regardless of the opening degree of the throttle valve 40c, and intake air can be drawn only from the tumble passage 64. can. Further, by fully opening the throttle valve 40c and fully opening the intake air distribution valve 68, more intake air can be taken in through both the tumble passage 64 and the main passage 66.

　In the internal combustion engine 10, two

fuel injection valves

70 and 72 are provided. The first fuel injection valve 70 is provided to inject fuel into a portion of the intake passage downstream of the throttle valve 40c and upstream of the intake distribution valve 68. As shown in FIG. Also, the second fuel injection valve 72 is provided so as to inject fuel into the main passage 66 on the downstream side of the intake distribution valve 68 . The fuel injection amount and injection timing from each of these two

fuel injection valves

70 and 72 are controlled in association with control of the throttle valve 40c and the intake distribution valve 68, respectively. Although two

fuel injection valves

70 and 72 are provided in the present embodiment, the present invention is not limited to this. only one fuel injection valve 72 may be provided. Further, the throttle valve 40c is not limited to being electronically controlled, and may be a valve mechanically controlled by a throttle cable, for example.

An ECU (electronic control unit) 76 that controls the internal combustion engine 10 has a configuration as a so-called computer, and includes an intake control section 78 and a fuel injection control section 80 . That is, the ECU 76 includes a processing unit or processor, for example a CPU, and a storage device or memory including, for example, ROM and RAM. The ECU 76 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 each operation of the throttle valve 40c and the intake distribution valve 68 by the intake control unit 78. do. The ECU 76 also controls the operation of each of the

fuel injection valves

70 and 72 based on the analyzed operating state of the internal combustion engine 10 . For example, under a predetermined operating condition such as a high load, the ECU 76 controls the operations of the throttle valve 40c and the intake air distribution valve 68 so that they are fully opened. Further, in this predetermined operating state, the ECU 76 calculates the fuel injection amount and/or the injection timing of the first fuel injection valve 70 based on pre-stored data, and based on these, the first fuel injection control the operation of the fuel injection valve 70. Similarly, in this predetermined operating state, the ECU 76 calculates the fuel injection amount and/or the injection timing of the second fuel injection valve 72 based on pre-stored data, and based on these, the first 2 fuel injection valve 72 is controlled. In addition, in a predetermined operating state such as a high load, the internal combustion engine 10 positively generates a tumble flow and increases the amount of intake air, as will be described later. The amount is relatively reduced compared to the conventional method. That is, in a predetermined operating state, the internal combustion engine 10 performs lean combustion.

Now, the structure of the intake passage 38 provided with the partition portion 62 will be further described. 2A through 2C show cross-sectional views of the internal combustion engine 10. FIG. 2A is a cross-sectional view of the internal combustion engine 10 along line IIA-IIA in FIG. 1, FIG. 2B is a cross-sectional view of the internal combustion engine 10 along line IIB-IIB in FIG. 2 is a cross-sectional view of the internal combustion engine 10 taken along line IIC-IIC; FIG. In this specification, the "left" direction and "right" direction of the intake passage 38 and the like used as shown in FIGS. It is the crossing direction. However, the "left" direction and the "right" direction shown in FIG. 2 correspond to the directions when the internal combustion engine 10 is mounted on the vehicle. The right direction is the direction extending toward the back side of the paper surface in FIG. 1, and the left direction is the direction extending toward the front side of the paper surface. These "left" and "right" directions also do not imply absolute directions in space.

As shown in FIGS. 2A, 2B and 2C, the intake passage 38 is divided by a partition 62 such that the main passage 66 is positioned above and the tumble passage 64 is positioned below the main passage 66. The partition portion 62 is provided so as to partition the tumble passage 64 into the intake passage 38, and extends in the intake passage 38 in the intake flow direction so as to separate it from the main passage 66 located above it. do. That is, the partition 62 extends into the intake passage 38 so as to define the tumble passage 64 below the main passage 66 . Here, the main passageway 66 is designed to have a cross-sectional area greater than that of the tumble passageway 64, as is evident from FIG. 2A, for example.

FIG. 2A is a cross-sectional view of the intake passage 38 at the intake port 32, taken along line IIA-IIA in FIG. It is a diagram. The tumble passage 64 has a substantially circular cross section, and the main passage 66 is positioned above it. 2A, when defining a line L1 extending vertically through the central axis (flow direction axis) 64A of the tumble passage 64, the main passage 66 and the intake passage 38 are substantially symmetrical with respect to this line L1. 2A, the main passage 66 extends downward on both sides of the tumble passage 64 so as to extend across the left and right sides of the tumble passage 64 in the intake air flow direction. That is, in FIG. 2A, the main passage 66 is provided with extension portions 66b on the left and right sides of the tumble passage 64, respectively, which extend downward.

2B is a cross-sectional view of the intake passage 38 at the intake port 32 at a location downstream of the cross-sectional location of FIG. FIG. 2 is a cross-sectional view in an imaginary plane along line IIB-IIB of FIG. 1 which intersects perpendicularly; Again, the tumble passage 64 has a substantially circular cross-section, and the main passage 66 is located above it. Also in FIG. 2B, when defining a line L2 extending vertically through the flow direction axis 64A of the tumble passage 64, the main passage 66 and the intake passage 38 are substantially symmetrical with respect to this line L2. 2B, the enlarged portion 66b of the main passageway 66 extends further below the flow direction axis 64A on both sides of the tumble passageway 64 than in FIG. 2A. 2B, the expanded portion 66b of the main passage 66 extends across both sides of the tumble passage 64 in the intake air flow direction, in other words, the width of the tumble passage 64 perpendicular to the intake air flow direction. The partition part 62 is formed so as to extend on both left and right sides in the direction. At this time, the portion of the main passage 66 immediately above the tumble passage 64 becomes narrower than in FIG. 2A due to the intake valve 46 . Therefore, the intake air in the main passage 66 will easily flow to the expanded portions 66b on both sides of the tumble passage 64. As shown in FIG.

FIG. 2C is a cross-sectional view of the intake passage 38 at the intake port 32 at a position further downstream than the cross-sectional position of FIG. , and is a cross-sectional view on a virtual plane along line IIC-IIC in FIG. Since partition 62 does not extend to this point, there is no boundary between main passage 66 and tumble passage 64 here. The intake passage 38 is also substantially symmetrical with respect to the line L3 extending vertically through the flow direction axis 64A of the upstream tumble passage 64 in FIG. 2C.

As shown in FIG. 2C, a wall portion 80 that defines the intake passage 38 is provided with a wall portion 82 whose curvature changes greatly when coming from the surroundings. The wall portion 82 is provided on the downstream side of the partition portion 62 and is hereinafter referred to as the downstream side wall portion. Downstream sidewall 82 is designed to alter, or deflect, the flow of intake air from main passageway 66 . The downstream side wall portions 82 are provided on both left and right sides of an upper wall portion (hereinafter referred to as an upper side wall portion) 80u extending along an extension line of the main passage 66 among the wall portions 80 defining the air intake passage 38 in the flow direction of the intake air. 2C so as to face the flow direction axis 38A side of the intake passage 38. As shown in FIG. Specifically, the downstream side wall portion 82 directs the flow of intake air from, for example, the expanded portion 66b of the main passage 66 to the combustion chamber, from the side of the flow of intake air from the tumble passage 64 to the combustion chamber to the opening of the intake valve 64. It is designed to allow directing to the intake side opening side of the The upper wall portion 80u includes the aforementioned curved outer wall portion 32a of the intake port 32 on which the intake valve 46 is supported via the intake valve guide 44. As shown in FIG.

The downstream side wall portion 82 is provided downstream of the partition portion 62 so as to direct the flow of intake air from the main passage 66 to the combustion chamber 20 in a direction that intersects the flow direction of the intake air from the tumble passage 64 to the combustion chamber 20. This is the wall where the The downstream side wall portion 82 is also a wall portion provided on the upstream side of the umbrella portion 46a of the intake valve 46, and is located on the upper side in FIG. 2C. Therefore, the downstream side wall portion 82 is the wall portion on the first direction side, that is, the upper side wall portion of the wall portion 80 defining the intake passage 38 .

Here, FIGS. 3 to 5 show a three-dimensional model M of the portion 38d of the intake port 32 (hereinafter referred to as the downstream portion) on the downstream side of the intake passage 38. FIG. 3 is a perspective view from above of the downstream portion 38d of the intake passage 38. FIG. FIG. 4 is a view of the downstream portion 38d of the intake passage 38 from the left-right direction of the three-dimensional model M, that is, from a direction orthogonal to the cylinder axis C and the direction extending from the intake side to the exhaust side. FIG. 5 is a bottom view of the three-dimensional model M of the downstream portion 38d of the intake passage 38. As shown in FIG.

3, 4 and 5, in the downstream portion 38d of the intake passage 38, the tumble passage 64 divided by the partition 62 merges with the main passage 66 on the downstream side of the partition 62 to form a generally circular shape. , and is connected to the combustion chamber 20. The internal combustion engine 10 has a single intake valve 46, and the downstream circle 38e in FIG. Here, a plurality of auxiliary lines are shown on the three-dimensional model M so as to facilitate understanding of its shape.

FIG. 6A shows a cross-sectional view of the three-dimensional model M at a position along line VIA-VIA in FIG. 4, FIG. A cross-sectional view along the line VIC--VIC is shown in FIG. 6C. As it moves downstream from FIG. 6A to FIG. 6C, the surface M1 becomes convex inside the intake passage 38 . A face M1 having this shape conforms to the shape of the downstream sidewall 82 of FIG. 2C. Therefore, the surface M1, that is, the downstream side wall portion 82, is configured so that the wall portion 80 defining and forming the intake passage 38 mainly has an outwardly convex surface, so here the wall portion defining and forming the intake passage 38 is It has a curved shape in the opposite direction to 80 , in other words, it has a curvature smaller than the average curvature of the wall 80 defining the intake passage 38 .

Here, in FIG. 4, the axis of the intake valve 46 (hereinafter referred to as the valve axis) 46c, the midpoint between the valve axis 46c and the exhaust side end 46d of the intake valve port 28, which is the seat portion or opening of the intake valve 46. An imaginary line L4 passing through 46e and parallel to valve axis 46c is shown. 4 shows the downstream side of the intake passage as seen from the direction in which the partition portion 62 extends, that is, the direction perpendicular to the extending direction of the partition valve 62 and the direction perpendicular to the valve axis 46c of the intake valve 46. corresponds to Fig. In FIG. 4, the surface M1 is partially provided on the exhaust side of the valve axis 46c of the intake valve 46, and positioned on the valve axis 46c side of the imaginary line L4. This is because, in the internal combustion engine 10, when the intake passage is viewed from a direction perpendicular to the valve axis 46c of the intake valve 46 (that is, in FIG. It corresponds to being positioned between the axis 46c and an imaginary line L4 passing through the midpoint 46e between the exhaust-side end 46d of the intake valve port 28 of the intake valve 46 and the valve axis 46c and parallel to the valve axis 46c. At least a portion of the downstream side wall portion 82, preferably substantially all of it, is preferably provided along the valve axis 46c, specifically substantially parallel to the valve axis 46c, like the plane M1 shown in FIG. . This is to effectively direct the flow of intake air from the main passage in a direction that will be described later.

FIG. 7 shows a portion of the internal combustion engine 10 with the downstream side of the intake passage 38 enlarged. FIG. 7 is a sectional view of an imaginary plane that roughly bisects the intake port 32 of the intake passage 38 and includes the cylinder axis C, viewed from a direction perpendicular to the imaginary plane. 7 is a view of the downstream side of the intake passage 38 viewed from a direction orthogonal to the extending direction of the gate valve 62, and also a view viewed from a direction orthogonal to the valve axis 46c of the intake valve 46. be. Of the two downstream side wall portions 82, FIG. 7 shows the downstream side wall portion 82 located on the far side of the intake valve 46 so as to be distinguishable from the surrounding wall surface defining the intake port 32. As shown in FIG. More specifically, in FIG. 7, the downstream side wall portion 82 is hatched. Here, the downstream side wall portion 82 configured as described above starts from the region where the partition portion 62 extends in the direction of intake air flow and extends to the vicinity of the intake valve port 28 of the intake valve 46 . As a result, the intake air from the main passage 66 is directed to the intake side of the intake valve port 28 of the intake valve 46, that is, the intake side opening 28i. Note that the downstream side wall portion 82 may be provided so as to start from a position on the downstream side of the downstream edge 62a of the partition portion 62 and extend downstream thereof. Further, the downstream side wall portion 82 is not limited to extending to the vicinity of the intake valve port 28 of the intake valve 46. It may be formed so as to extend to a point extending in the intake flow direction.

Further, FIG. 7 shows the downstream end 64b of the tumble passage 64 at the downstream edge 62a of the partition 62, that is, the central axis 64c of the outlet in the flow direction. In FIG. 7, the exhaust side opening range of the intake valve 46 when the valve is open, that is, the exhaust side valve curtain 46f is indicated by a dashed line. The valve curtain 46f is the trajectory of the umbrella portion 46a of the intake valve 46 that reciprocates along the valve axis 46a when the intake valve 46 is open. 7, the central axis 64c of the downstream end 64b of the tumble passage 64 extends through the exhaust side valve curtain 46f of the intake valve 46 on the exhaust side of the valve axis 46c. That is, the central axis 64c of the downstream end 64b of the tumble passage 64 extends through the exhaust side opening 28e of the intake valve port 28 in FIG.

The operation and effect of the intake structure S of the internal combustion engine 10 having the above configuration will be described below.

A schematic diagram of a downstream portion 38d of the intake passage 38 is shown in FIGS. 8A and 8B. FIG. 8A is a top view of the downstream portion 38d, and FIG. 8B is a left-right view of the downstream portion 38d. 9 shows a schematic cross-sectional view of the internal combustion engine 10 on a virtual plane that bisects the intake passage 38 into right and left and includes the cylinder axis C. As shown in FIG. 8A, 8B and 9, intake air from the tumble passage 64 is labeled "G1" and intake air from the main passage 66 is labeled "G2". 8A, 8B, and 9 schematically show the flow of intake air in the above-described predetermined operating state in which the throttle valve 40c and the intake air distribution valve 68 are fully opened.

As shown in FIGS. 8 and 9, when the intake valve 46 is open, the intake air from the tumble passage 64 flows straight into the combustion chamber 20 through the opening of the intake valve 46, that is, the exhaust side opening 28e of the intake valve port 28. flow from As described with reference to FIG. 7, the internal combustion engine 10 is arranged such that the flow direction axis 64c of the downstream end of the tumble passage 64 passes through the portion of the valve curtain of the intake valve 46 on the exhaust side of the valve axis 46c. is designed.

Further, when the intake valve 46 is opened in the above-described predetermined operating state, the intake air from the main passage 66 mainly flows from the upper side of the tumble passage 64 to the outside thereof, and then flows inward, as shown in FIG. 8A. As shown in FIGS. 8B and 9, the intake air from the tumble passage 64 intersects with the flow of intake air and enters the combustion chamber 20 at the intake side opening 28i of the intake valve opening 28 of the intake valve 46. flow from This is because, as described above, the main passageway 66 is provided with an extension 66b extending downward on the side of the tumble passageway 64 as described, for example, with reference to FIGS. 2A and 2B, and the downstream wall portion 82 is provided. because it is

FIG. 10A shows the results of a computer simulation performed to verify the effects of the internal combustion engine 10. FIG. However, the various conditions of this computer simulation imitated the above-described predetermined operating state in which the

various valves

40c and 68 of the intake passage are fully opened. FIG. 10B also shows a computer simulation result of an internal combustion engine having an intake structure different from the intake structure S of the internal combustion engine 10 (hereinafter referred to as a comparative internal combustion engine).

Here, the intake structure of the comparative internal combustion engine will be explained based on FIGS. 11A and 11B. 11A and 11B show schematic diagrams of the downstream portion of the intake passage of the comparative internal combustion engine. FIG. 11A is a top view of the downstream portion of the intake passage of the comparative internal combustion engine, and FIG. 11B is a lateral view of the downstream portion of the intake passage of the comparative internal combustion engine. 11A and 11B, the intake air from the tumble passage is labeled "G1", and the intake air from the main passage is labeled "G2". Unlike the intake structure S of the internal combustion engine 10, the intake structure of the comparative internal combustion engine does not include the downstream side wall portion 82, and the expanded portion of the main passage is narrower and shallower than the expanded portion 66b of the internal combustion engine 10. FIG.

Returning to FIGS. 10A and 10B, the explanation of the computer simulation results continues. In FIGS. 10A and 10B, each line represents a streamline, and the denser the streamline, the denser the flow of intake air, ie, the greater the inflow. 10A and 10B, for example, region XA in FIG. 10A and region XB in FIG. It has been found that there are more streamlines extending into the combustion chamber 20 . This is probably because the comparative internal combustion engine does not have the downstream side wall portion 82 and the flow G2 is easily affected by the flow G1, whereas in the internal combustion engine 10 the direction of the flow G2 is changed with respect to the flow G1 as described above.

In addition, the flow rate of intake air flowing through the intake port 32 was measured by computer simulation under the same conditions as the computer simulations of FIGS. 10A and 10B. The results are shown in FIG. As shown in FIG. 12, in the internal combustion engine 10 (example in FIG. 12), a larger intake flow rate could be obtained than in the comparative internal combustion engine (comparative example in FIG. 12). This is because in the internal combustion engine 10, it is possible to generate the flow of intake air from the tumble passage 64 and the flow of intake air from the main passage 66 as described with reference to FIGS. 8A, 8B and 9. deaf. 10A, more intake air can be introduced into the combustion chamber 20 through the intake-side opening 28i of the intake valve port 28. As shown in FIG. As described above, since the internal combustion engine 10 is provided with the intake structure S, the intake air can be drawn into the combustion chamber more effectively.

Furthermore, FIG. 13 shows the result of measuring and averaging the flow velocity of intake air in the combustion chamber of the internal combustion engine, that is, in the cylinder, by computer simulation. FIG. 13 is a graph plotting the crank angle when the intake valve 46 is open on the horizontal axis and the flow velocity of the intake air on the vertical axis. It should be noted that there is a relationship that the faster the flow velocity of the intake air, the faster the combustion velocity, so the vertical axis in FIG. 13 can be replaced with the combustion velocity. From FIG. 13, it was found that the internal combustion engine 10 (Example of FIG. 13) can obtain a higher flow velocity of intake air in the combustion chamber than the comparative internal combustion engine (Comparative example of FIG. 13). This can improve the intake air flow from the main passage 66 from being affected by the intake air flow from the tumble passage 64 as described above, and the tumble flow in the combustion chamber 20 can be made more effective with the intake air flow from the tumble passage 64. This is probably because it can be generated dynamically (see flow G1 in FIG. 9, for example).

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.

For example, in the internal combustion engine, the partition portion 62 is provided so as to divide the intake passage 38 into two passages, the tumble passage 64 and the main passage 66 . However, the present disclosure does not exclude that the partition is configured to divide the intake passage into three or more. Also, the internal combustion engine 10 employs a SOHC type two-valve system, thus providing a single intake valve per cylinder. However, the internal combustion engine 10 may be configured with two or more intake valves per cylinder.

10... internal combustion engine, 12... cylinder block, 14... cylinder head, 16... piston,
20... combustion chamber, 28... intake valve port,
30...Exhaust valve opening, 32...Intake port, 34...Exhaust port, 38...Intake passage,
40... throttle body, 46... intake valve,
50 ... Exhaust valve,
62... partition, 64... tumble passage, 66... main passage, 68... intake diverting valve,
70, 72...fuel injection valve, 76...ECU,
82 ... wall portion (downstream side wall portion),
S: Intake structure.

Claims

A partition (62) configured to divide the intake passage (38) into a plurality of sections, the partition separating a first intake passage (64) and a second intake passage (66) in the intake passage (38). a part (62);
The flow of intake air from the second intake passage (66) to the combustion chamber (20) is directed in a direction that intersects the flow direction of intake air from the first intake passage (64) to the combustion chamber (20). and a downstream side wall portion (82) provided downstream of the partition portion (62).
When the direction from the crankshaft side to the cylinder head (14) side in the direction of the cylinder axis (c) is defined as the first direction, and the direction opposite to the first direction is defined as the second direction,
The partition (62) extends into the intake passage (38) so as to define the first intake passage (64) on the second direction side of the second intake passage (66),
2. The internal combustion engine according to claim 1, wherein the downstream side wall portion (82) extends in the first direction of a wall portion (80) defining the intake passageway (38). 10) Intake structure (S).
3. The intake structure for an internal combustion engine (10) according to claim 2, wherein at least part of the downstream side wall portion (82) extends along the valve axis (46c) of the intake valve (46). S).
When viewed from a direction orthogonal to the extending direction of the partition (62) and orthogonal to the valve axis (46c) of the intake valve (46),
At least part of the downstream side wall portion (82) is provided closer to the exhaust side than the valve axis (46c) of the intake valve (46), and is located on the exhaust side of the opening (28) of the intake valve (46). It is provided closer to the valve axis (46c) than an imaginary line (L4) passing through the middle point (46e) between the side end (46d) and the valve axis (46c) and parallel to the valve axis (46c). 4. An intake structure (S) for an internal combustion engine (10) according to claim 2 or 3, characterized in that:
The central axis (64c) in the flow direction of the outlet of the first intake passage (64), which is defined at the downstream edge (62a) of the partition (62), corresponds to the center axis (64c) when the intake valve (46) is open. 5. The intake structure (S) for an internal combustion engine (10) according to any one of claims 2 to 4, wherein the intake structure (S) extends so as to penetrate the exhaust side opening range (46f) of the intake valve.
When the direction from the crankshaft side to the cylinder head (14) side in the direction of the cylinder axis (c) is defined as the first direction, and the direction opposite to the first direction is defined as the second direction,
The downstream side wall portion (82) regulates the flow of intake air from the second intake passage (66) to the combustion chamber (20) and the flow of intake air from the first intake passage (64) to the combustion chamber (20). 6. The intake structure (S) for an internal combustion engine (10) according to any one of claims 1 to 5, characterized in that the intake structure (S ).
The internal combustion engine (10) has a single intake valve (46),
The partition (62) is formed so that the second intake passage (66) extends across both sides of the first intake passage (64) in the direction of flow of intake air,
The downstream side wall portion (82) is provided on the downstream side of the second intake passage (66) so as to be located on both sides in the intake flow direction of the intake valve (46). 7. An intake structure (S) for an internal combustion engine (10) according to 6 above.
The downstream side wall portion (82) regulates the flow of intake air from the second intake passage (66) to the combustion chamber (20) and the flow of intake air from the first intake passage (64) to the combustion chamber (20). 8. The internal combustion engine according to claim 7, characterized in that it is provided so as to face from the flow side toward the intake side opening (28i) of the openings (28) of the intake valve (46). (10) intake structure (S).
The downstream side wall portion (82) has a curvature smaller than the average curvature of the wall portion (80) defining the intake passageway (38),
An intake structure (S) for an internal combustion engine (10) according to any one of claims 1 to 8, characterized in that: