JP3617796B2 - Intake device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for an internal combustion engine that includes a bypass air passage that bypasses a throttle valve and communicates with an intake passage downstream of the throttle valve. More specifically, a rotary air control valve that controls the amount of bypass air is provided. The structure of the bypass air passage provided.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an intake device for an internal combustion engine that includes a bypass air passage that bypasses a throttle valve provided in an intake passage and communicates with an intake passage downstream thereof, the rotary air control valve provided in the bypass air passage is opened. By controlling the degree, the amount of bypass air is controlled to control the number of idle rotations of the internal combustion engine.
[0003]
In this idle speed control, the bypass air that passes through the air control valve is throttled by the air control valve, and therefore, turbulence including the frequency in the audible frequency range occurs immediately downstream of the outlet, that is, pressure fluctuation occurs. Air passing sound based on pressure fluctuation is generated. The bypass air including the pressure fluctuation flows into the intake passage at a high speed and vibrates the intake pipe, thereby generating noise that is a vehicle interior sound. The magnitude of this noise was particularly noticeable when a resin intake pipe having a lower rigidity than that of a metal intake pipe was used.
[0004]
Therefore, in order to reduce such noise, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-47163, in an auxiliary air control device for an internal combustion engine, a grid-like rectifier blade is provided in the auxiliary air passage with an air control valve. Further, a passage expansion chamber is provided in an auxiliary air passage downstream of the rectifying blade. Since this rectifying blade rectifies the disturbance of the auxiliary air that has passed through the air control valve, the excitation force of the intake pipe by the rectified auxiliary air is weakened, and noise is reduced. Furthermore, since the auxiliary air rectified by the rectifying blades flows into the passage expansion chamber and the flow velocity thereof is reduced, noise is further reduced.
[0005]
Further, in the technique disclosed in Japanese Patent Laid-Open No. 5-209564, an orifice or a sleeve is provided in the straight pipe portion of the outlet side bypass passage located downstream of the idle speed control valve in the idle speed control device. Thus, the passage area can be changed stepwise. Therefore, based on the air vibration generated in the outlet side passage of the idle speed control valve, the vibration that resonates in the outlet side bypass passage is forcibly disturbed by the orifice, sleeve, etc. Resonance in the bypass passage and the surge tank of the intake system is suppressed, and the generation of abnormal noise is prevented.
[0006]
[Problems to be solved by the invention]
By the way, in the techniques of both publications, in the former, the grid-like rectifying blades are provided over the entire flow passage cross section of the auxiliary air passage, and in order to perform an effective rectifying action, the number of grids Therefore, the air flow resistance tends to increase. In the latter case, the flow resistance of the air increases because the flow path of the outlet side bypass passage is restricted by the orifice or sleeve provided over the entire circumference of the outlet side bypass passage. Therefore, in order to prevent a decrease in the amount of air measured by the control valve due to an increase in flow resistance, the air passage in the portion where the rectifying blade, orifice or sleeve is provided has a relatively large diameter. Accordingly, the diameter of the air passage formed in the throttle body is increased, and there is room for improvement in terms of reducing the size and weight of the throttle body.
[0007]
The present invention has been made in view of such circumstances, and in an intake device of an internal combustion engine, noise generated from an intake pipe into which bypass air flows is reduced, and the throttle body is reduced in size and weight. For the purpose.
[0008]
[Means for Solving the Problems and Effects of the Invention]
The invention according to claim 1 of the present application provides an intake air passage formed by a throttle body and an intake pipe attached to the throttle body, a rotary air control valve having a valve housing attached to the throttle body, A bypass air passage having an outlet that bypasses the throttle valve provided in the intake passage in the throttle body and opens to the intake passage downstream of the throttle valve, and passes through the bypass air passage by the air control valve In an intake device for an internal combustion engine in which an air amount of bypass air is controlled, a part of the bypass air passage, which is formed in the valve housing from an outflow hole located immediately downstream of the valve body of the air control valve. An outlet side bypass air passage leading to the outlet is formed in the valve housing and communicates with the outlet hole. That a first outflow passage, and a second outlet passage said connected are formed in the throttle body to the first outlet passage,The outlet hole includes a fully closed end that first forms a control opening in cooperation with the valve body when the air control valve opens from a closed state, and the control when the air control valve is fully opened. A fully open end that forms an opening in cooperation with the fully closed end;In the outflow side bypass air passage, a step portion is formed by the cooperation of the passage wall surface of the first outflow passage of the valve housing and the step portion of the throttle body, and the step portion is formed in the first outflow passage.SaidFully closed endSideThe outlet side bypass air passage with respect to the passage wall surface;Only at the fully closed endIt protrudes inward and has a length corresponding to the interval in the direction parallel to the rotation axis of the valve body between the passage wall surfaces of the first outflow passage, and extends in the direction parallel to the rotation axis. Furthermore, the step portion has a step surface that deflects a part of the bypass air from the outflow hole in a direction from the base end of the step portion toward the tip end of the step portion.The step portion causes the stepped surface of the bypass air to flow out of the outflow hole and flow through the first outflow passage when the air control valve has a small opening compared to when the air control valve has a large opening. Increases the proportion of impinging bypass airAn intake device for an internal combustion engine.
[0009]
According to the first aspect of the present invention, when the air control valve is operated, the bypass air measured by the air control valve flows out from the outflow hole to the first outflow passage at a high speed. Part of the bypass air flowing through the first outflow passage collides with the step surface of the step portion and is deflected toward the tip of the step portion, so that the pressure fluctuation of itself is reduced.
[0010]
Further, the bypass air deflected by colliding with the step surface isBaseSince the air flow is directed toward the front end and becomes turbulent in the bypass air flowing between the front end and the passage wall surface of the outflow side bypass air passage, the pressure fluctuation of the bypass air is alleviated. Therefore, the pressure fluctuation of the bypass air after passing through the step portion is smaller than that of the bypass air before passing through the step portion, and the pressure fluctuation when flowing into the intake passage is also reduced. As a result, the vibration of the intake pipe due to the bypass air flowing into the intake passage is suppressed, and noise is reduced.
[0011]
Also, compared to when the air control valve is opened or fully opened (hereinafter simply referred to as “when the valve is opened”), the bypass air has a pressure fluctuation in the audible frequency range that is recognized as noise in the vehicle. It has been proved by experiments that the stepped portion has a fully closed end in the first outflow passage.SideFor the passage wallOnly at the fully closed end of the outflow bypass air passageDue to the protrusion, when the air control valve is in a small opening, the proportion of the bypass air that collides with the stepped surface out of the bypass air that flows out from the outflow hole and flows through the first outflow passage is larger than when the air control valve is in a large opening.
[0012]
Therefore, when the air control valve is in a small opening, a larger proportion of bypass air collides with the step surface and is deflected than in the case of a large opening. The bypass air causes a stronger turbulence in the bypass air flowing between the front end and the passage wall surface of the outflow side bypass air passage, so that the pressure fluctuation of the bypass air is further alleviated. As a result, it is possible to effectively reduce the noise of the intake pipe due to the bypass air at the time of a small opening having a large pressure fluctuation in the audible frequency range recognized as noise in the vehicle.
[0013]
Furthermore, since the step portion is only partially provided in the circumferential direction of the passage wall surface only on the fully closed end side of the outflow side bypass air passage, the air flow resistance by the step portion is relatively small. It is possible to suppress an increase in the cross-sectional area of the side bypass air passage, and thus it is possible to reduce the size and weight of the throttle body in which the second outflow passage that is a part of the outflow side bypass air passage is formed.
[0014]
According to a second aspect of the present invention, in the intake device for an internal combustion engine according to the first aspect, the step portion of the throttle body, wherein the tip portion forms a passage wall surface having no step of the second outflow passage, It is a portion having a mating surface with the valve housing, and the step surface is on the same plane as the mating surface.
[0015]
According to the second aspect of the present invention, since the step portion is formed by utilizing the mating surface of the throttle body with the valve housing, it is the outflow side bypass air passage formed in the throttle body by the step portion. No step is formed on the wall surface of the second outflow passage. As a result, the cross-sectional area of the second outflow passage can be reduced, and the throttle body can be further reduced in size and weight.
[0016]
In addition, since the step portion is formed by the portion having the mating surface of the throttle body, it is not necessary to provide a special structure for forming the step portion. Therefore, the structure of the throttle body is simplified and the cost is reduced. It can be reduced.
[0017]
According to a third aspect of the present invention, in the intake device for an internal combustion engine according to the first or second aspect, the outflow side bypass air passage is formed in the intake pipe, and one end thereof is connected to the second outflow passage. , Further comprising a third outflow passage having the other end serving as the outlet, the third outflow passage is provided with an expansion chamber integrally formed with the intake pipe, and the flow passage cross-sectional area of the expansion chamber is: The flow passage cross-sectional area of each of the outflow side bypass air passages upstream and downstream of the expansion chamber is made larger.
[0018]
According to the third aspect of the present invention, since the flow rate of the bypass air is reduced in the expansion chamber, the pressure fluctuation is further alleviated, so that the vibration of the intake pipe is further suppressed and the noise is further reduced. Further, since the expansion chamber is formed in the intake pipe, the bypass air passage structure of the throttle body can be simplified, and further, the throttle body can be reduced in size and weight.
[0019]
In this specification, the fully closed end refers to a central point that bisects the distance between the fully closed end and the fully open end of the outflow hole formed in the valve housing of the air control valve, and the air control valve. This is the side where the fully closed end of the outflow hole is located with respect to a virtual plane including a virtual straight line parallel to the rotation axis of the valve body and the center point of the bypass air passage on the mating surface of the valve housing with the throttle body.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS.
1 to 4 show a first embodiment. In this embodiment, the internal combustion engine to which the invention of the present application is applied is a spark ignition type four-cylinder internal combustion engine. An aluminum throttle body 1, an air cleaner 2 attached to the upper surface of the throttle body 1, and a resin intake manifold 3 attached to the lower surface of the throttle body 1 are provided. The intake passage 5 formed by the throttle body 1 and the intake manifold 3 is a downflow type intake passage through which air flows from the upper side to the lower side in the vertical direction.
[0021]
On the side surface of the throttle body 1, a valve housing 7 of a rotary air control valve 6 (hereinafter referred to as an “air control valve”) abuts a mating surface 1a on the throttle body 1 side and a mating surface 7a on the valve housing 7 side. The bypass air control device including the bypass air passage 8 and the air control valve 6 is constituted by the throttle body 1, the air control valve 6, and the intake manifold 3.
[0022]
Among these, the bypass air passage 8 includes an inflow-side bypass air passage 9 that is a bypass air passage 8 upstream of the valve body 16 and a bypass air passage downstream of the valve body 16 with respect to the valve body 16 of the air control valve 6. 8 and an outflow side bypass air passage 10.
[0023]
The inflow side bypass air passage 9 is formed in the throttle body 1 in the horizontal direction, one end forms an inlet 11a that opens to the intake passage 5 upstream of the throttle valve 4, and the other end opens to the mating surface 1a. 1 inflow passage 11, formed in the valve housing 7, one end connected to the first inflow passage 11 at the mating surface 7 a and the other end to the second inflow passage 12 reaching the valve body 16. The inflow side bypass air passage 9 has a circular flow path cross section as shown in FIG.
[0024]
The outflow side bypass air passage 10 is formed in the valve housing 7 in the horizontal direction, one end is formed in the valve housing 7 and is located immediately downstream of the valve body 16 and communicates with the outflow hole 17, and the other end is formed. A first outflow passage 13 opening in the mating surface 7a and a throttle body 1 are formed. One end is connected to the first outflow passage 13 at the mating surface 1a, and the other end is connected to a third outflow passage 15 described later. The second outflow passage 14 is formed in the intake manifold 3. One end of the second outflow passage 14 is connected to the second outflow passage 14 and the other end forms an outlet 15 a that opens to the intake passage 5 downstream of the throttle valve 4. 3 outflow passages 15. And the 1st outflow passage 13 and the horizontal part 14e which is the part formed in the horizontal direction of the 2nd outflow passage 14 are the part in which the step part 1b mentioned later was formed, as FIG. 2 shows. Except for the same rectangular channel cross section.
[0025]
Further, the third outflow passage 15 is formed with an expansion chamber 15b in the middle thereof, and the flow passage cross-sectional area of the expansion chamber 15b is a portion of the third outflow passage 15 located upstream of the expansion chamber 15b, the second outflow passage. 14 and the flow passage cross-sectional area of the first outflow passage 13 and the flow passage cross-sectional area of the portion of the third outflow passage 15 located downstream of the expansion chamber 15b.
[0026]
On the other hand, the air control valve 6 includes a valve body 16 that is integrally fixed to a drive shaft 18 that is rotated by a solenoid (not shown). The arcuate plate-like valve body 16 rotates around the rotation axis of the drive shaft 18 extending in the horizontal direction, thereby forming a control opening 19 formed by the cooperation of the outflow hole 17 and the valve body 16. By changing the opening area continuously, the amount of bypass air flowing through the bypass air passage 8 is controlled to control the idle speed of the internal combustion engine.
[0027]
Referring to FIGS. 2 to 4, the outflow hole 17 first forms a control opening 19 in cooperation with the valve body 16 when the air control valve 6 is opened from the closed state. It has a fully closed end 17a, and has a fully open end 17b at its uppermost portion that forms a control opening 19 when the air control valve 6 is fully opened in cooperation with the fully closed end 17a.
[0028]
Further, the portion of the outflow side bypass air passage 10 constituted by the first outflow passage 13 and the second outflow passage 14 includes a passage wall surface of the first outflow passage 13 and a step portion 1b provided in the throttle body 1. A stepped portion 20 is formed by cooperation. The step portion 20 has a central point P1 that bisects the distance between the fully closed end of each of the first outflow passage 13 and the second outflow passage 14, that is, the full closed end 17a and the full open end 17b of the outflow hole 17. And the virtual plane P3 including the virtual straight line L (see FIG. 2) parallel to the rotational axis of the valve body 16 and the center point P2 of the first outflow passage 13 on the mating surface 7a, It is located on the side where the closed end 17a is located.
[0029]
More specifically, the step portion 20 is located on the fully closed end side of the first outflow passage 13, is substantially parallel to the fully closed end 17 a, and is positioned below the fully closed end 17 a and the lower passage wall surface 13 a. The second outflow passage 14 is formed by a stepped portion 1b provided on the throttle body 1 and integrally formed with the throttle body 1 on the fully closed end side.
[0030]
The step portion 1b protrudes from the lower passage wall surface 14a, which is a passage wall surface only on the fully closed end side of the second outflow passage 14, to the inside of the second outflow passage 14, that is, upward, at a predetermined height. In the outflow passage 14, it extends in a direction parallel to the rotation axis and is formed across the both-side passage wall surfaces 14b and 14c. Therefore, when the first outflow passage 13 is used as a reference, the step portion 1b is on the same plane as the lower passage wall surface 14a of the second outflow passage 14 and is opposed to the lower passage wall surface 13a that is the passage wall surface only on the fully closed end side. Projecting inward of the second outflow passage 14 and having a length corresponding to the interval in the direction parallel to the rotational axis of the side wall surfaces 13b, 13c of the first outflow passage 13, It extends in a direction parallel to the rotation axis.
[0031]
Further, the step portion 1b has a step surface 1c that faces the outflow hole 17 and is flush with the mating surface 1a of the throttle body 1 and is formed together with the mating surface 1a. A part of the bypass air which is measured at the control opening 19 and flows out from the outflow hole 17 to the first outflow passage 13 collides with the surface 1c. The bypass air that has collided with the stepped surface 1c is deflected from the base end 1d of the stepped portion 1b toward the tip end 1e, thereby relaxing the pressure fluctuation of the stepped surface 1c.
[0032]
In addition, the bypass air deflected by colliding with the stepped surface 1c becomes an air flow having an upward velocity component and flows between the tip 1e, which is the space above the tip 1e, and the upper passage wall surface 14d. By causing turbulence in the air, the pressure fluctuation of the bypass air is alleviated.
[0033]
The amount of bypass air to be deflected and the magnitude of the upward velocity component are determined by the step 1b, which is a portion intersecting the lower passage wall surface 13a of the first outflow passage 13.Base 1dSince this depends on the height of the step surface 1c from the tip 1e to the tip 1e, that is, the height of the step portion 1b, this height is the flow path of the passage formed between the tip 1e and the upper passage wall surface 14d. As a cross-sectional area, a flow passage cross-sectional area that is large enough not to squeeze the measured bypass air is secured, and the degree of relaxation of the pressure fluctuation of the deflected bypass air itself, the bypass flowing above the tip 1e It is appropriately set in consideration of the degree of turbulence generated in the air, and therefore the degree of relaxation of the pressure fluctuation of the bypass air.
[0034]
In this embodiment, the front end 1e of the stepped portion 1b is set higher than the fully closed end 17a with respect to the lower passage wall surface 13a of the first outflow passage 13.
[0035]
Further, the stepped surface 1c is a surface that protrudes from the fully closed end 17a with respect to the outflow hole 17, that is, a surface that intersects the lower passage wall surface 13a that is a passage wall surface on the fully closed end side of the first outflow passage 13 substantially perpendicularly. When the air control valve 6 is formed with a small opening, the air control valve 6 flows out from the outflow hole 17 as compared with the case where the air control valve 6 has a large opening (meaning that the opening is large or fully opened as described above). The ratio of the bypass air which collides with the level | step difference surface 1c among the bypass air which flows through the 1 outflow passage 13 is made large.
[0036]
Next, operations and effects of the embodiment configured as described above will be described.
During idle operation of the internal combustion engine in which the throttle valve 4 is fully closed, the intake passage 5 downstream of the throttle valve 4 is in a high negative pressure state, so that air from the air cleaner 2 is upstream of the throttle valve 4. From the inlet 11a of the engine, the air flows into the intake manifold 3 from the outlet 15a downstream of the throttle valve 4 through the bypass air passage 8 and is supplied to each cylinder.
[0037]
At that time, the valve body 16 of the air control valve 6 is supplied to the intake manifold 3 through the bypass air passage 8 so that the rotation speed of the internal combustion engine becomes a preset idle rotation speed according to the engine operating state. It is rotated to control the amount of bypassed air. During this idle operation, when an auxiliary device such as an air conditioner is driven, for example, the valve body 16 is rotated in the valve opening direction so that the idle speed does not decrease due to an increase in load, and the control opening 19 is increased. As a result, more bypass air is supplied to the intake manifold 3 to maintain the set idle speed. Conversely, when the load decreases, the valve body 16 is rotated in the valve closing direction, and the amount of bypass air supplied to the intake manifold 3 is reduced, thereby preventing an increase in the idle speed. Thus, the set idle speed is maintained.
[0038]
When the air amount of the idle air is controlled by the air control valve 6 in this way, the air passing through the control opening 19 of the air control valve 6 is throttled, so that the frequency in the audible frequency range is included immediately downstream thereof. Since turbulence, that is, pressure fluctuation occurs, a passing sound of bypass air is generated based on the pressure fluctuation.
[0039]
The bypass air measured by the air control valve 6 flows out from the outflow hole 17 to the first outflow passage 13 at a high speed. A part of the bypass air flowing through the first outflow passage 13 collides with the stepped surface 1c and is deflected toward the tip 1e of the stepped portion 1b, so that the pressure fluctuation of itself is reduced.
[0040]
Further, the bypass air deflected by colliding with the stepped surface 1c becomes an air flow from the base end 1d of the stepped portion 1b toward the tip 1e, and is disturbed by the bypass air flowing between the tip 1e and the upper passage wall surface 14d. Therefore, the pressure fluctuation of the bypass air is reduced. Therefore, the pressure fluctuation of the bypass air after passing through the step portion 20 is smaller than that of the bypass air before passing through the step portion 20, and when the air flows into the intake passage 5 of the intake manifold 3. Pressure fluctuation is also small. As a result, the vibration of the intake manifold 3 due to the bypass air flowing into the intake passage 5 is suppressed, and noise is reduced.
[0041]
Furthermore, in this embodiment, since the expansion chamber 15b is formed in the third outflow passage 15, bypass air whose pressure fluctuation has been reduced by the step portion 1b flows into the expansion chamber 15b through the second outflow passage 14. Since the flow velocity of the bypass air decreases in the expansion chamber 15b, the pressure fluctuation is further alleviated. As a result, vibration of the intake manifold 3 is further suppressed, and noise is further reduced.
[0042]
Further, the step portion 1b is opposed to the lower passage wall surface 13a which is the passage wall surface on the fully closed end side in the first outflow passage 13.Second outflow passage 14 Only on the fully closed end ofThe ratio of the bypass air that collides with the stepped surface 1c out of the bypass air that flows out from the outflow hole 17 and flows through the first outflow passage 13 when the air control valve 6 is small opening compared to when the air control valve 6 is large opening. Becomes larger.
[0043]
Therefore, when the air control valve 6 is in a small opening, a larger proportion of the bypass air collides with the stepped surface 1c and is deflected compared to when the air control valve 6 is in a large opening. Since a large proportion of the bypass air causes stronger turbulence in the bypass air flowing between the tip 1e and the upper passage wall surface 14d of the second outflow passage 14, the pressure fluctuation of the bypass air is further alleviated. As a result, compared to when the air control valve 6 is opened to a large degree, the noise in the intake manifold 3 due to the bypass air at the time of a small opening having a large pressure fluctuation in the audible frequency range recognized as noise in the vehicle is effective. Can be reduced.
[0044]
Furthermore, since the tip 1e of the step portion 1b is higher than the fully closed end 17a with respect to the lower passage wall surface 13a of the first outflow passage 13, the bypass air flowing out from the lower portion of the control opening 19 is stepped surface 1c. Therefore, the bypass air can be deflected more easily.
[0045]
Furthermore, the step portion 1b is provided to protrude at a predetermined height from the lower passage wall surface 14a which is a part of the circumferential direction of the passage wall surface only on the fully closed end side of the second outflow passage 14 constituting the outflow side bypass air passage 10. Therefore, the ratio of the step portion 1b in the flow path cross section of the second outflow passage 14 is small. Accordingly, the air flow resistance is relatively small, and an increase in the flow passage cross-sectional area of the second outflow passage 14 can be suppressed. Therefore, the throttle body 1 in which the second outflow passage 14 is formed can be reduced in size and weight.
[0046]
Further, since the expansion chamber 15b is formed in the intake manifold 3, the structure of the bypass air passage 8 formed in the throttle body 1 can be simplified, and also in this respect, the throttle body 1 can be reduced in size and weight.
[0047]
Hereinafter, with reference to FIG. 5 and FIG. 6, 2nd and 3rd embodiment of this invention is described.
[0048]
FIG. 5 shows a second embodiment, in which the stepped portion 30 b does not protrude inward of the second outflow passage 14 and forms a passage wall surface without a step in the second outflow passage 14. It is formed by a portion having 30 mating surfaces 30a. Other configurations are basically the same as those of the first embodiment, and corresponding members are denoted by the same reference numerals.
[0049]
Therefore, in the second embodiment, the step portion 30b that forms the step portion 31 in cooperation with the lower passage wall surface 13a of the first outflow passage 13 is a passage wall surface only on the fully closed end side in the first outflow passage 13. The outflow side bypass air passage 10 has a lower passage wall surface 13a.Only on the fully closed endIt protrudes inward and has a length corresponding to the interval in the direction parallel to the rotational axis of the valve body 16 between the side passage walls of the first outflow passage 13 and in the direction parallel to the rotational axis. It extends. Further, the step surface 30c that intersects the lower passage wall surface 13a at a substantially right angle faces the outflow hole 17 and is continuous with the mating surface 30a on the same plane, and is formed together with the mating surface 30a. Is.
[0050]
The tip 30e of the step portion 30b forms a step wall surface of the second outflow passage 14, and the flow passage cross-sectional area of the second outflow passage 14 is such that the measured bypass air is not restricted. In size, at least the horizontal portions 14e of the second outflow passages 14 all have substantially the same flow path cross-sectional area.
[0051]
According to the second embodiment configured as described above, the same functions and effects as those of the first embodiment are achieved, and unlike the first embodiment, the flow passage cross-sectional area of the second outflow passage 14 is increased. It is not necessary to increase the cross-sectional area of the second outflow passage 14 in the portion of the second outflow passage 14 that is once reduced by the portion and is not provided with the stepped portion. Since at least the horizontal cross-sectional area of the horizontal portion 14e of the second outflow passage 14 is substantially the same, the vertical dimension of the throttle body 30 can be reduced, and the throttle body 30 can be reduced in size and weight. As a result, the height of the internal combustion engine can be reduced, and the internal combustion engine can be made compact.
[0052]
Further, since the stepped portion 30b is formed by the portion having the mating surface 30a of the throttle body 30, it is not necessary to provide a special structure separately to form the stepped portion 30b, so that the structure of the throttle body 30 is simple. Thus, the cost can be reduced.
[0053]
FIG. 6 shows a third embodiment, in which a stepped portion 40b formed in the throttle body 40 has an overhang portion 40f extending into the first outflow passage 13, and the stepped portion 41 is in the first outflow. It is formed in the passage 13. Other configurations are basically the same as those of the first embodiment, and corresponding members are denoted by the same reference numerals.
[0054]
In this third embodiment, the step portion 40b that forms the step portion 41 in cooperation with the lower passage wall surface 13a of the first outflow passage 13 is the lower wall surface that is the passage wall surface only on the fully closed end side of the first outflow passage 13. Each of the first outflow passage 13 and the second outflow passage 14 with respect to the passage wall surface 13a.Only on the fully closed endThe length of the valve body 16 between the side passage wall surfaces of the first outflow passage 13 extends in the direction parallel to the rotation axis with a length corresponding to the interval in the direction parallel to the rotation axis. ing. Further, a step surface 40c that intersects the lower passage wall surface 13a at a substantially right angle is formed on a surface facing the outflow hole 17 of the overhang portion 40f.
[0055]
According to the third embodiment configured as described above, the same operation and effect as in the first embodiment are achieved, and the step surface 40 c of the step portion 40 b is formed in the first outflow passage 13 with the outflow hole 17. Since it can be formed closer, the amount of bypass air deflected and the magnitude of the upward velocity component can be changed without changing the height of the stepped portion 40b by changing the length of the overhang portion 40f. The degree of relief of pressure fluctuation due to the bypass air from the outflow hole 17 being deflected by colliding with the stepped surface 40c, and the air flow that is deflected upward is formed as a step portion. The strength of the turbulence generated in the bypass air flowing between the tip 40e of 40b and the upper passage wall surfaces 13d, 14d of the first outflow passage 13 and the second outflow passage 14, and thus the pressure of the bypass air It is possible to increase the degree of freedom of adjustment of the degree of relaxation of the change.
[0056]
Hereinafter, an embodiment in which a part of the configuration of each embodiment is changed will be described.
In the first and third embodiments, the step portions 1b and 40b are formed integrally with the throttle bodies 1 and 40. However, the throttle bodies 1 and 40 are separated from the throttle bodies 1 and 40 by a fixing means such as screws. By sticking to, the step part of the throttle bodies 1 and 40 can also be formed. Thus, by preparing a member having various heights or various overhang lengths with the step portion as a separate member, the height can be adjusted, and in the third embodiment, the length of the overhang length can be adjusted. Adjustment is easy.
[0057]
In each of the above embodiments, the step surfaces 1c, 30c, and 40c intersect the lower passage wall surface 13a of the first outflow passage 13 at a substantially right angle, but the step surfaces 1c, 30c, and 40c are the step surfaces 1c, 30c. , 40c may be inclined with respect to the lower passage wall surface 13a as long as it deflects air from the base ends 1d, 30d, 40d toward the tips 1e, 30e, 40e. Moreover, although the front-end | tip 1e, 30e, 40e vicinity is a corner | angular part, you may make it round and form so that the flow of an air flow may become smooth.
[0058]
In each said embodiment, although the shape of the flow-path cross section of the horizontal part 14e of the 1st outflow passage 13 and the 2nd outflow passage 14 was a rectangle, respectively, a circular shape may be sufficient. The intake passage 5 is a down flow type, but may be a horizontal flow type intake passage. The intake manifold 3 is made of resin, but may be made of metal.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an essential part of an intake device for an internal combustion engine according to a first embodiment of the present invention.
2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a partially enlarged view of FIG. 1, and is a cross-sectional view when the air control valve is opened.
FIG. 4 is a cross-sectional view when the air control valve is closed.
FIG. 5 is a partially enlarged view of an intake device for an internal combustion engine according to a second embodiment of the present invention, and a sectional view when the air control valve is opened.
FIG. 6 is a partially enlarged view of an intake device for an internal combustion engine according to a third embodiment of the present invention, and a sectional view when the air control valve is opened.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Throttle body, 1a ... Matching surface, 1b ... Step part, 1c ... Step surface, 1d ... Base end, 1e ... Tip, 2 ... Air cleaner, 3 ... Intake manifold, 4 ... Throttle valve, 5 ... Intake passage, 6 DESCRIPTION OF SYMBOLS ... Rotary type air control valve, 7 ... Valve housing, 7a ... Mating surface, 8 ... Bypass air passage, 9 ... Inflow side bypass air passage, 10 ... Outflow side bypass air passage, 11 ... First inflow passage, 12 ... Second Inflow passage, 13 ... first outflow passage, 13a ... lower passage wall surface, 14 ... second outflow passage, 14a ... lower passage wall surface, 15 ... third outflow passage, 15a ... outlet, 15b ... expansion chamber, 16 ... valve body, 17 ... Outflow hole, 17a ... Fully closed end, 17b ... Fully open end, 18 ... Drive shaft, 19 ... Control opening, 20 ... Stepped part,
30 ... Throttle body, 30a ... mating surface, 30b ... stepped portion, 30c ... stepped surface, 30d ... proximal end, 30e ... tip, 31 ... stepped portion,
40 ... Throttle body, 40a ... Mating surface, 40b ... Step portion, 40c ... Step surface, 40d ... Base end, 40e ... Tip, 40f ... Overhang portion, 41 ... Step portion,
L ... Virtual straight line, P1 ... Center point, P2 ... Center point, P3 ... Virtual plane.

Claims (3)

An intake passage formed by a throttle body and an intake pipe attached to the throttle body, a rotary air control valve having a valve housing attached to the throttle body, and a throttle provided in the intake passage in the throttle body An internal combustion engine having a bypass air passage having an outlet opening to the intake passage downstream of the throttle valve by bypassing the valve, wherein the amount of bypass air passing through the bypass air passage is controlled by the air control valve In the intake system of
An outflow side bypass air passage that is a part of the bypass air passage and is formed in the valve housing and extends from an outflow hole that is located immediately downstream of the valve body of the air control valve to the outlet is formed in the valve housing. A first outflow passage communicating with the outflow hole, and a second outflow passage formed in the throttle body and connected to the first outflow passage,
The outlet hole includes a fully closed end that first forms a control opening in cooperation with the valve body when the air control valve opens from a closed state, and the control when the air control valve is fully opened. A fully open end that forms an opening in cooperation with the fully closed end;
In the outflow side bypass air passage, a step portion is formed by the cooperation of the passage wall surface of the first outflow passage of the valve housing and the step portion of the throttle body,
Stepped portion is configured to protrude only inwardly in該全closed side of the outflow-side bypass air passage for the previous SL passage wall surface of the entire closed side of the first outlet passage, the first outlet passage Extending in a direction parallel to the rotation axis, with a length corresponding to the interval in a direction parallel to the rotation axis of the valve body between the wall surfaces of the passage,
Further, the step portion has a step surface for deflecting a part of the bypass air from the outflow hole in a direction from the base end of the step portion toward the tip of the step portion, and the step control portion allows the air control valve to be deflected. The ratio of the bypass air that collides with the stepped surface out of the bypass air that flows out from the outflow hole and flows through the first outflow passage is larger than when the air control valve is at a large opening. An intake system for an internal combustion engine. The step portion is a portion having a mating surface with the valve housing of the throttle body, the tip of which forms a passage wall surface without a step of the second outflow passage, and the step surface is the mating surface 2. The intake device for an internal combustion engine according to claim 1, wherein the intake device is on the same plane as the internal combustion engine. The outflow side bypass air passage is further formed with a third outflow passage which is formed in the intake pipe, has one end connected to the second outflow passage and the other end serves as the outlet, An expansion chamber integrally formed with the intake pipe is provided, and the flow passage cross-sectional area of the expansion chamber is larger than the flow passage cross-sectional areas of the outflow side bypass air passages upstream and downstream of the expansion chamber. 3. The intake device for an internal combustion engine according to claim 1, wherein the intake device is enlarged.

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