JP2009185653A - Intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device for an internal combustion engine capable of performing both the inhibition of air flow noise and the homogeneous dispersion of addition gas. <P>SOLUTION: An induction conduit 2 includes a first induction conduit 4 for supporting a valve stem 3a of a butterfly valve 3; a second induction conduit 5 having a flow passage area larger than that of the first induction conduit 4, and continuously arranged at the downstream side of the first induction conduit 4; and a third induction conduit 6 having a flow passage area smaller than that of the second induction conduit 5, and continuously arranged at the downstream side of the second induction conduit 5. The second induction conduit 5 includes a flow passage area enlarged portion 5a with the flow passage area on the one half 3b side of the butterfly valve 3 larger than the flow passage area on the other half 3c side, and a flow passage area gradually narrowed portion 5b continuously arranged at the downstream side of the flow passage area enlarged portion 5a, for making the flow passage area of the second induction conduit 5 gradually become closer to the flow passage area of the third induction conduit 6. An addition gas introducing port 8 is provided in the vicinity of the boundary of the second and third induction conduits 5, 6 for introducing the addition gas into the induction conduit 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intake device for an internal combustion engine in which a butterfly valve is disposed in an intake pipe that supplies air to the internal combustion engine.

In this type of intake device, when the fully closed butterfly valve is suddenly opened, the intake air flow that has passed through both ends of the butterfly valve merges on the downstream side of the butterfly valve, and an annoying airflow sound is generated. In particular, if the intake pipe is made of resin, the sound of the airflow is further increased due to the reflection of the intake pipe. Therefore, by expanding the flow path area on the downstream side of the butterfly valve, the pressure energy when the intake air flows join is released, and the generation of airflow noise is suppressed (see Patent Document 1).
Japanese Patent Laid-Open No. 10-121994 (paragraphs 0029 to 0031, FIG. 2)

  By the way, additional gas such as EGR gas or blow-by gas is introduced into the intake pipe of the internal combustion engine. However, when a flow passage area enlarged portion as shown in Patent Document 1 is provided, selection of the installation location of the additional gas introduction port is selected. Becomes difficult. That is, when the flow passage area enlargement section is not provided, an vortex of the intake flow is generated immediately downstream of the butterfly valve. Conventionally, an additional gas introduction port is provided there to uniformly diffuse the additional gas in the intake pipe. It was. However, if the flow passage enlargement portion as shown in Patent Document 1 is provided, the vortex of the intake air flow is less likely to be generated. Therefore, if the additional gas inlet is provided near the butterfly valve, There is a possibility that the additional gas rides on one of the different intake flows and does not diffuse uniformly in the intake pipe. On the other hand, if the additional gas inlet is too far away from the butterfly valve, the intake flow is rectified at that position, so that the additional gas tends to be biased and diffused toward the inlet. In short, when the technique of Patent Document 1 is adopted, the generation of airflow noise can be suppressed, but it becomes difficult to uniformly diffuse additional gas into the intake air. In particular, in a multi-cylinder internal combustion engine, the concentration of the additional gas differs from cylinder to cylinder, causing a problem of variation in combustion.

  In view of such circumstances, an object of the present invention is to provide an intake device for an internal combustion engine capable of both suppressing generation of airflow noise and uniform diffusion of additional gas.

  In order to solve the above-mentioned problems, the present invention provides an intake device for an internal combustion engine in which a butterfly valve is disposed in an intake pipe that supplies air to the internal combustion engine, and a first intake pipe portion that supports a valve shaft of the butterfly valve. A second intake pipe portion having a flow passage area larger than the flow passage area of the first intake pipe portion and continuously provided downstream of the first intake pipe portion, and a flow path of the second intake pipe portion The intake pipe is configured with a third intake pipe portion having a flow path area smaller than the area and continuously provided downstream of the second intake pipe portion, and the second intake pipe portion includes the butterfly valve A channel area enlarged portion in which the channel area on one half side is larger than the channel area on the other half side, and the channel area of the second intake pipe section is the channel area of the third intake pipe section. In order to gradually approach the channel area, a channel area gradually decreasing portion connected downstream of the channel area expanding portion is provided. Further, wherein the vicinity of the boundary between the second and third suction pipe portion, characterized in that a additional gas inlet for introducing an additional gas into the intake pipe.

  According to this configuration, the intake air that has passed through the passage on one half side of the butterfly valve flows into the flow passage area enlarged portion of the second intake pipe portion to reduce the flow velocity, while passing through the other half side passage. Since the intake air flows along the inner surface of the second intake pipe portion, the flow rate of the former intake flow is smaller than that of the latter intake flow. For this reason, since two intake air flows merge at a position offset in the axial direction in the intake pipe, a direct collision of the intake air flow is avoided and generation of airflow noise is suppressed. On the other hand, in the vicinity of the boundary between the second and third intake pipe portions, the intake flows having different flow velocities merge to form a strong turbulent flow, so that the additional gas rides on the strong turbulent flow and diffuses into the intake pipe.

  It is preferable that the additional gas inlet is arranged in a region on the same intake pipe circumference as the flow path area gradually decreasing portion or in a region near the boundary between the second and third intake pipe portions downstream of the region.

  According to such a configuration, since the intake flow whose flow velocity has been reduced by passing through the flow passage area enlarged portion is guided to the flow passage area gradually decreasing portion, the boundary between the second intake pipe portion and the third intake pipe portion. A flow toward the axial center of the second intake pipe portion is formed on the upstream side. On the other hand, the flow rate of the intake air flow that has not passed through the enlarged flow channel area is higher than the flow rate of the intake air flow that has passed through the enlarged flow channel area portion. On the other hand, in other words, a flow toward the axial center of the third intake pipe portion is formed on the downstream side of the boundary between the second intake pipe portion and the third intake pipe portion. For this reason, the two intake flows merge near the boundary between the second intake pipe portion and the third intake pipe portion, and a strong turbulent flow is generated in a region on the same intake pipe circumference as the flow passage area gradually decreasing portion. Therefore, the additional gas can be diffused more uniformly by arranging the additional gas introduction port in this region or slightly downstream thereof.

  It is preferable that the flow path area enlarged portion is arranged so as to increase the flow area on the half body side that is inclined to the upstream side of the butterfly valve.

  According to such a configuration, the flow rate can be gradually adjusted by the butterfly valve, and the intake control with a low flow rate can be performed.

  The additional gas introduction port is disposed in the vicinity of the boundary between the flow path on one half side of the butterfly valve and the flow path on the other half side, and the valve shaft of the butterfly valve substantially extends from the additional gas introduction port. It is preferable to introduce the additional gas into the intake pipe in a parallel direction.

  According to such a configuration, there is no possibility that the additional gas is diffused by being biased to one of the flow path on one half side of the butterfly valve and the flow path on the other half side, and the diffusion effect is further improved.

  The first intake pipe portion is formed of a throttle body, the second and third intake pipe portions are formed of an intake manifold, and the flow passage area enlarged portion is adjacent to a joint surface of the intake manifold to the throttle body. It is preferable to form them.

  According to such a configuration, when the second and third intake pipe portions are molded, there is no restriction in the mold release direction, and it is possible not only to suppress an increase in molding cost, but also to easily increase the volume of the channel area expansion portion. And helps reduce airflow noise.

  It is preferable that the flow passage area enlarged portion is provided with a rib that extends inside the intake pipe shaft core.

  According to this configuration, since the rigidity of the intake pipe is improved, the airflow sound is less likely to be reflected in the intake pipe, and the airflow sound can be further reduced. Further, since the rib is accommodated in the flow path area enlarged portion, the rib does not protrude from the flow path of the first intake pipe portion or the third intake pipe portion, and the first intake pipe portion and the third intake air are not projected. A reduction in the flow area of the pipe portion (in other words, a reduction in volumetric efficiency of the internal combustion engine) is avoided. Moreover, since the rib extends along the intake pipe axis, an increase in intake resistance can be suppressed.

  The rib is preferably formed such that at least one of its height and width increases toward the downstream side.

  According to this configuration, the flow passage area of the second intake pipe portion changes gradually with respect to the intake pipe axial center direction, and the flow passage area of the second intake pipe portion gradually increases to the flow passage area of the third intake pipe portion. Therefore, the effect of suppressing the intake resistance is further increased.

  According to the present invention, since the intake air that has passed through both halves of the butterfly valve merges at a position offset in the axial direction in the intake pipe, the generation of airflow noise due to the direct collision of the intake air can be suppressed. Further, in the vicinity of the boundary between the second and third intake pipe portions, intake flows having different flow velocities merge to form a strong turbulent flow, so that additional gas is placed on the turbulent flow and uniformly diffused in the intake pipe. Can do.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1 is a view showing an intake device for an internal combustion engine according to the present invention, and is a cross-sectional view taken along line AA of FIG. FIG. 2 is a view of the intake manifold of FIG. 1 as viewed from the open end.

  This intake device 1 is provided with a butterfly valve 3 inside an intake pipe 2 and controls the amount of air supplied to the internal combustion engine by adjusting the opening degree. The intake pipe 2 includes a first intake pipe portion 4 formed of a throttle body incorporating a butterfly valve 3 and second and third intake pipe portions 5 formed of a resin intake manifold communicating with the first intake pipe portion 4. , 6. Each of the intake pipe portions 4, 5, and 6 has a flow path having a circular cross section, and the axial centers CL thereof are aligned to be connected. The flow passage area of the first intake pipe portion 4 is substantially equal to the flow passage area of the third intake pipe portion 6. However, the flow passage area of the second intake pipe portion 5 is larger than the flow passage areas of the first and third intake pipe portions 4 and 6 by the provision of the flow passage area enlarged portion 5a and the flow passage area gradually decreasing portion 5b. It is getting bigger. A valve shaft 3a of the butterfly valve 3 is rotatably supported on the first intake pipe portion 4. The butterfly valve 3 is arranged so that its tip end enters the second intake pipe 5 when the valve is opened. Note that the butterfly valve 3 in the closed state is indicated by a two-dot chain line in FIG.

  The second intake pipe unit 5 tilts the area of the flow path 20 on the first half 3b side that tilts upstream of the two halves 3b and 3c constituting the butterfly valve 3 to the downstream side. A channel area enlarged portion 5a that is larger than the area of the channel 30 on the half body 3c side is provided. The flow paths 20 and 30 on the first and second half bodies 3b and 3c side are the insides of the intake pipe 2 defined by the surface extending the valve shaft 3a of the butterfly valve 3 along the intake pipe axis CL. Space. In the cross section shown in FIG. 1 (the cross section including the intake pipe axis CL that is orthogonal to the valve shaft 3a of the butterfly valve 3), the flow passage area enlarged portion 5a is a part of the peripheral wall of the second intake pipe portion 5 outside the radial direction. It is formed to bulge out. The channel area enlarged portion 5a is formed in a substantially semicircular shape when viewed from the opening end of the second intake pipe portion 5 (see FIG. 2).

  A flow passage area gradually decreasing portion 5 b is provided downstream from the flow passage area enlarged portion 5 a so that the flow passage area of the second intake pipe portion 5 is equal to the flow passage area of the third intake pipe portion 6. That is, the channel area gradually decreasing portion 5b is formed such that the channel area gradually decreases toward the downstream side. Further, a pair of ribs 7 extending along the intake pipe axis CL are provided in the flow channel area enlarged portion 5a and the flow channel area gradually decreasing portion 5b. The upper surfaces of the ribs 7 and 7 are flush with the inner surfaces 4 a and 6 a of the first and third intake pipe portions 4 and 6. In the present embodiment, the ribs 7 are arranged symmetrically with respect to the line AA in FIG.

  The intake pipe 2 is provided with an additional gas introduction port 8 for introducing additional gas (EGR gas, blow-by gas, evaporated fuel, etc.) into the downstream side of the butterfly valve 3. This additional gas inlet 8 is a region on the same intake pipe circumference as the flow passage area gradually decreasing portion 5b, and is disposed at the boundary between the flow passages 20 and 30 on the first and second half bodies 3b and 3c side. It is. Specifically, the additional gas introduction port 8 is disposed slightly upstream from the boundary between the second and third intake pipe portions 5 and 6. Further, additional gas is introduced into the intake pipe 2 from the additional gas introduction port 8 in a direction substantially parallel to the valve shaft 3 a of the butterfly valve 3. The intake manifold 9 is provided with a hose connection pipe 10 connected to the additional gas introduction port 8 (see FIG. 2).

  Flange 11, 12 is provided at the open ends of the first and second intake pipe portions 4, 5, and the first and second intake pipe portions 4 are interposed between the flanges 11, 12 with a sealing material 13 interposed therebetween. , 5 are connected to each other. Thereby, the flow passage area enlarged portion 5 a of the second intake pipe portion 5 forms a discontinuous step adjacent to the flange 11 of the first intake pipe portion 4.

  In the intake device 1, the intake air that has passed through the passage a on the first half 3 b side that is inclined to the upstream side of the butterfly valve 3 flows into the flow passage area enlarged portion 5 a of the second intake pipe portion 5 to reduce the flow velocity. On the other hand, since the intake air that has passed through the passage b on the other half 3c side flows along the inner surface of the second intake pipe section, the flow rate of the former intake air flow A is smaller than that of the latter intake air flow B. Thereafter, the two intake flows A and B are curved toward the center of the second intake pipe section 5, but the intake flow A having a low flow velocity has a higher degree of curvature than the intake flow B having a high flow velocity. The two intake flows A and B merge at a position offset in the axial direction in the intake pipe 2. That is, the direct collision of the two intake air flows A and B is avoided, and the generation of airflow noise due to the direct collision of the intake air A and B is suppressed. As a result, even if the butterfly valve 3 in the fully closed state is suddenly opened, no loud airflow noise is generated as in the conventional case.

  By the way, the intake air flow A whose flow velocity has been reduced by passing through the flow passage area enlarged portion 5a is guided to the flow passage area gradually decreasing portion 5b, so that the second intake pipe portion 5 and the third intake pipe portion 6 A flow toward the axis CL of the second intake pipe portion 5 is formed upstream of the boundary. On the other hand, since the intake air flow B that has not passed through the flow passage area enlarged portion 5a has a flow velocity larger than that of the intake air flow A that has passed through the flow passage area enlarged portion 5a, the intake air flow that has passed through the flow passage area enlarged portion 5a. The flow toward the axial center CL of the third intake pipe portion 6 is formed further downstream than the boundary between the second intake pipe portion 5 and the third intake pipe portion 6. . For this reason, the two intake flows A and B are merged in the vicinity of the boundary between the second intake pipe portion 5 and the third intake pipe portion 6, and the region on the same intake pipe circumference as the flow passage area gradually decreasing portion 5b. Since a strong turbulent flow is generated at this point, the additional gas can be uniformly diffused by arranging the additional gas inlet 8 in this region or slightly downstream thereof. In short, in order to uniformly diffuse the additional gas into the intake pipe 2, it is most preferable to arrange the additional gas inlet 8 in this way. However, since the additional gas rides on the turbulent flow and diffuses into the intake pipe 2, the additional gas inlet 8 is arranged at a certain distance from the boundary between the second and third intake pipe portions 5 and 6 to the upstream and downstream sides. However, a sufficient diffusion effect can be expected.

  Further, since the additional gas introduction port 8 is arranged at the boundary between the flow paths 20 and 30 on the first and second half bodies 3b and 3c, the flow paths 20 and 30 on the first and second half bodies 3b and 3c side are arranged. There is no risk of the additional gas diffusing to be biased to any one of 30 and the diffusion effect is improved. Further, since the additional gas is introduced into the intake pipe 2 from the additional gas introduction port 8 in a direction substantially parallel to the valve shaft 3 a of the butterfly valve 3, that is, the additional gas is introduced into the intake pipe 2 from the additional gas introduction port 8. Since it is made to flow toward the center, the bias of the additional gas is eliminated and the diffusion effect is further improved. As long as the additional gas inlet 8 is disposed in the vicinity of the boundary between the flow paths 20 and 30, it may be slightly separated from the boundary.

  By the way, since the flow passage area enlarged portion 5a is arranged so as to enlarge the area of the flow passage 20 on the half body 3b side inclined to the upstream side of the butterfly valve 3, the flow rate adjustment by the butterfly valve 3 can be gradually performed. Low flow rate intake control (such as idle control) is possible. If the flow path area enlarged portion 5a is arranged so as to increase the area of the flow path 30 on the half 3c side that is inclined to the downstream side of the butterfly valve 3, when the opening of the butterfly valve 3 is increased, When the tip of the half 3c reaches a position facing the flow passage area enlarged portion 5a, the flow passage area increases rapidly, and intake control at a low flow rate becomes difficult.

  In the intake device 1, the first intake pipe portion 4 is formed of a throttle body, and the second and third intake pipe portions 5 and 6 are formed of a resin intake manifold, and the flow path of the second intake pipe portion 5 Since the discontinuous step is formed adjacent to the flange 11 of the first intake pipe portion 4 in the area enlarged portion 5a, there is a restriction in the mold release direction when the second and third intake pipe portions 5 and 6 are formed. It does not occur, and the rise in molding cost can be suppressed. Moreover, the volume expansion of the flow path area enlarged portion 5a is facilitated, which helps to reduce the air flow noise.

  Further, since the rigidity is enhanced by providing a pair of ribs 7 on the flow channel area enlarged portion 5a and the flow channel area gradually decreasing portion 5b, the air flow noise is less likely to reverberate in the intake pipe 2, and the air flow noise can be further reduced. The ribs 7 and 7 extend along the intake pipe axis CL, and their tips are flush with the inner surfaces 4a and 6a of the first and third intake pipe portions 4 and 6, and the flow passage area enlarged portion 5a and the flow are increased. Since it is accommodated in the road area gradually decreasing portion 5b, an increase in intake resistance can be suppressed. That is, airflow noise can be reduced while suppressing an increase in intake resistance.

[Modification]
3 is a view showing a modification of the second and third intake pipe portions of FIG. 1, and is a cross-sectional view corresponding to the line AA of FIG. 4 is a cross-sectional view taken along line BB in FIG.
A pair of ribs 70 extending along the intake pipe axis CL are provided in the flow channel area enlarged portion 5a and the flow channel area gradually decreasing portion 5b. These ribs 70 and 70 are gradually increased in width toward the downstream side (see FIG. 4). Further, on the upper surface of each rib 70, an inclined surface 70a formed so that the height of the rib 70 gradually increases toward the downstream side, and a third intake pipe portion connected to the downstream side of the inclined surface 70a. 6 and the parallel surface 70b that is flush with the inner surface 6a are formed (see FIG. 3).

  When the rib 70 is formed in this way, the flow passage area of the second intake pipe portion 5 changes gently with respect to the intake pipe axis CL direction, and the flow passage area of the second intake pipe portion 5 changes to the third intake pipe portion. 6 is gradually approached, so that the effect of suppressing the intake resistance is further increased.

  In this modification, the height and width of the rib 70 are changed. However, the increase in the intake resistance can be suppressed to some extent only by changing either the height or the width.

By the way, when two types of additional gas are introduced into the intake pipe 2, it is most preferable to arrange the two additional gas introduction ports 8 in parallel with the valve shaft 3 a of the butterfly valve 3.
Further, when a large amount of additional gas is introduced into the intake pipe 2, as shown in FIG. 3, one additional gas introduction port 8 is disposed at the above-mentioned position, and the remaining additional gas introduction ports 80 are added. It may be arranged adjacent to the upstream side or downstream side of the gas inlet 8 or may be arranged adjacently on the same intake pipe circumference. At that time, in order to prevent tar in the blow-by gas from adhering to the adjacent additional gas introduction port 80, it is desirable that the blow-by gas introduction port be disposed downstream.

It is a figure which shows the intake device of the internal combustion engine of this invention, and is the sectional view on the AA line of FIG. FIG. 2 is a view of the intake manifold of FIG. 1 as viewed from an open end. It is a figure which shows the modification of the 2nd and 3rd intake pipe part of FIG. 1, and is sectional drawing corresponding to the AA line of FIG. FIG. 4 is a sectional view taken along line BB in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake device 2 Intake pipe 3 Butterfly valve 3a Valve shaft 3b 1st half 3c 2nd half 4 1st intake pipe part 5 2nd intake pipe part 5a Flow path area enlarged part 5b Flow path area gradually reduced part 6 3rd supply Trachea part 7 Rib 8 Additional gas inlet 9 Intake manifold 10 Hose connection pipe 11 Flange 12 Flange 13 Sealing material 20 First half side flow path 30 Second half side flow path A Intake flow B Intake flow a Passage b Passage CL CL Intake pipe Shaft core

Claims (7)

  In an intake device for an internal combustion engine in which a butterfly valve is disposed in an intake pipe that supplies air to the internal combustion engine, a first intake pipe portion that supports a valve shaft of the butterfly valve, and a flow path of the first intake pipe portion A flow passage area larger than the area, a second intake pipe portion provided downstream of the first intake pipe portion, and a flow passage area smaller than the flow passage area of the second intake pipe portion, The third intake pipe portion connected downstream of the second intake pipe portion constitutes the intake pipe, and the second intake pipe portion has a flow area on one half side of the butterfly valve on the other side. A flow passage area enlarged portion that is larger than a flow passage area on the half body side, and the flow passage area enlarged portion that gradually brings the flow passage area of the second intake pipe portion closer to the flow passage area of the third intake pipe portion. A flow passage area gradually decreasing portion provided downstream of the second and third intake pipes; The vicinity of the boundary, an intake system for an internal combustion engine, characterized by comprising an additional gas inlet for introducing an additional gas into the intake pipe.   The additional gas introduction port is disposed in a region on the same intake pipe circumference as the flow path area gradually decreasing portion or in a region near the boundary between the second and third intake pipe portions downstream of the region. The intake device for an internal combustion engine according to claim 1.   3. The internal combustion engine according to claim 1, wherein the flow passage area enlarged portion is arranged so as to enlarge a flow passage area on a half body side that is inclined to the upstream side of the butterfly valve. 4. Intake device.   The additional gas introduction port is disposed in the vicinity of the boundary between the flow path on one half side of the butterfly valve and the flow path on the other half side, and the valve shaft of the butterfly valve substantially extends from the additional gas introduction port. 4. The intake system for an internal combustion engine according to claim 1, wherein the additional gas is introduced into the intake pipe in a parallel direction.   The first intake pipe portion is formed of a throttle body, the second and third intake pipe portions are formed of an intake manifold, and the flow passage area enlarged portion is adjacent to a joint surface of the intake manifold to the throttle body. 5. The intake device for an internal combustion engine according to claim 1, wherein the intake device is formed as described above.   6. The intake device for an internal combustion engine according to claim 1, wherein a rib that is accommodated in the flow passage area enlarged portion and extends along an intake pipe axis is provided in the passage area enlarged portion.   2. The intake device for an internal combustion engine according to claim 1, wherein the rib is formed so that at least one of its height and width increases toward the downstream side.

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