JP3650534B2 - Throttle body with diffuser - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throttle body with a diffuser.
[0002]
[Prior art]
Conventionally, as shown in FIG. 8, as a throttle body disposed in an intake system of an internal combustion engine, a throttle shaft 102 can be rotated in a direction perpendicular to the axis XX of the portion 101 on a cylindrical throttle body portion 101. The throttle valve 103 is fixedly attached to the throttle shaft 102, and further, a diffuser 105 having a diffuser 105 having an inner surface 104 that expands on the downstream side is formed downstream of the throttle body 101. Is disclosed, for example, in JP-A-5-141262.
[0003]
[Problems to be solved by the invention]
By the way, the throttle body 106 with a diffuser expands the inner surface 104 of the diffuser 105 toward the downstream side, thereby suppressing the peeling phenomenon in which the streamlines of the airflow near the inner surface 104 are pushed out from the inner surface 104. The intake energy loss is reduced by reducing the intake energy loss. However, as in the conventional structure shown in FIG. 8, the throttle shaft 102 exists on the upstream side of the diffuser 105, and the downstream side of the throttle shaft 102. When the diffuser inner surface 104 is expanded with a smooth surface, the presence of the throttle shaft 102 causes turbulence and deceleration of the air flow downstream of the root portion, thereby causing the oblique lines in FIGS. 9 (a) and 9 (b). As shown in the figure, the airflow separation area A starts from the root of the throttle shaft 102 and diverges downstream. Jo to occur, a wide range of peeling zone A occurs. Therefore, the pressure loss increases due to the wide separation area A, and the intake loss increases.
[0004]
If the degree of intake loss is replaced with the diffuser performance, it can be expressed by the pressure recovery efficiency of the diffuser. If the pressure recovery efficiency is small, it can be said that the pressure loss is large.
[0005]
For example, as shown in FIG. 10, the pressure recovery efficiency is measured by disposing the throttle body 106 with a diffuser at the upstream end of the pseudo surge tank 108 and the vacuum pump 109 at the downstream end thereof. The static pressure P _{1 in the} vicinity and the static pressure P ₂ in the downstream portion of the diffuser 106 are measured, and can be obtained from the values by the following equation.
[0006]
Pressure recovery efficiency η = (P ₂ −P ₁ ) / P ₁
Then, as a result of obtaining the pressure recovery efficiency η by the above formula under the following test conditions for the throttle body 106 with a diffuser having the conventional structure, the value of η is 37.1% as shown by η ₁ in FIG. Met.
[0007]
Test conditions: Intake flow rate: In a 3-liter inline 6-cylinder engine, the throttle valve was fully opened, the rotation speed was 6000 rpm, and the intake amount was 10.3 m ³ / min (inlet flow velocity 60.75 m / s).
[0008]
Throttle valve opening: 90 ° (fully open)
Pulsation: None (steady flow)
Therefore, the conventional structure has a problem that the pressure recovery rate η ₁ is low, that is, there is a large intake loss.
[0009]
In view of the above, the present invention reduces the separation region generated in the downstream portion of the root portion of the throttle shaft in the conventional structure, and increases the pressure recovery efficiency η as compared with the conventional structure, thereby reducing the intake air loss. An object of the present invention is to provide a throttle body with a diffuser that improves engine output and improves engine output.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first invention according to claim 1 is characterized in that a throttle shaft is rotatably provided in a throttle body portion, a throttle valve is fixed to the throttle shaft, and a downstream side of the throttle body portion. Further, the diffuser is provided in a series, and the inner surface of the diffuser is provided with a rectifying convex portion from the vicinity of both side root portions of the throttle shaft toward the downstream side.
[0011]
When the throttle body with the diffuser of the present invention is attached to the intake system of the engine, when the throttle valve opens and the air is drawn from the throttle body portion side to the diffuser side, the airflow hits the throttle shaft, and the throttle shaft is attached to both sides. An air flow separation region occurs in the diffuser inner surface portion from the root portion to the downstream portion. As in the present invention, by providing the rectification convex portion on the inner surface of the diffuser from the vicinity of both root portions of the throttle shaft toward the downstream, the rectification convex portion Fills the separation area of the airflow, reduces the separation area, and rectifies. Therefore, the pressure loss due to the separation of the airflow is reduced, and the pressure recovery efficiency of the diffuser is improved and the amount of intake air is increased as compared with the conventional throttle body with a diffuser that does not have the rectifying convex portion.
[0012]
According to a second aspect of the present invention, in the first aspect of the invention, the ridge line of the rectifying convex portion is parallel to the axial center of the throttle body from the same surface as the inner surface of the throttle body portion to the downstream, and downstream thereof. The side is expanded in the radial direction.
[0013]
In the second aspect of the invention, the rectifying convex portion of the ridge line portion which is flush with the inner surface of the throttle body and parallel to the throttle body axis mainly controls the reduction of the air flow separation area, and reduces the pressure loss as described above. As a result, the pressure recovery efficiency of the diffuser is improved and the amount of intake air is increased.
[0014]
According to a third aspect of the present invention, in the first aspect, the ridge line of the straightening convex portion is inclined toward the axial center side of the diffuser from the same surface as the inner surface of the throttle body portion toward the downstream side. It is characterized by expanding in the radial direction from the vicinity of the downstream end.
[0015]
In the third aspect of the invention, the second narrow portion is formed in the vicinity of the downstream end of the diffuser at the ridge line of the rectifying convex portion, and the diffuser shaft core is extended over a long distance from the upstream end of the rectifying convex portion to the vicinity of the downstream end. Since the inclined surface in the direction is formed, the deceleration of the gas in the diffuser is suppressed on the inclined surface. Therefore, as compared with the second aspect of the invention, the air flow separation region is further reduced, the pressure loss is further reduced, the pressure recovery efficiency of the diffuser is further improved, and the intake air amount is increased.
[0016]
According to a fourth aspect of the present invention, in the first aspect, the ridge line of the rectifying convex portion is inclined toward the axial center side of the diffuser from the same surface as the inner surface of the throttle body portion toward the downstream side. The diameter is increased in the radial direction from the vicinity of the upstream end.
[0017]
In the fourth aspect of the invention, the second narrow portion is provided in the vicinity of the upstream end of the diffuser on the ridge line of the rectifying convex portion so that the downstream length from the second narrow portion is longer than that of the third aspect. The slope angle and length of the downstream ridge line can be formed to have the same gentle angle and length as the inner surface of the diffuser, that is, the angle and length that does not cause separation of the airflow. Therefore, the separation area downstream from the second narrowed portion is further reduced as compared with the first invention, the pressure loss is further reduced, the pressure recovery efficiency of the diffuser is further improved, and the intake air amount is further increased. Become.
[0018]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the width of the rectifying convex portion viewed from a plane orthogonal to the axis of the throttle shaft is set from the upstream side to the downstream side. It is characterized by widening toward the side.
[0019]
The separation region of the airflow usually occurs in a shape that spreads downstream from the throttle shaft on a surface orthogonal to the axis of the throttle shaft. Therefore, by forming the rectifying convex portion in a divergent shape according to the diverging peeling region, the peeling region can be effectively filled with the rectifying convex portion, and the rectifying convex portion of each of the inventions acts effectively.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described based on the examples shown in FIGS. FIG. 1 shows a first embodiment of the present invention, in which FIG. 1 (a) is a view as seen from the downstream side of a throttle body 1 with a diffuser, FIG. 1 (b) is a cross-sectional view along line YY in FIG. c) The figure is a ZZ line sectional view of (a) figure.
[0021]
In the first embodiment, the cylindrical throttle body portion 2 constituting the diffuser-equipped throttle body 1 is provided with a throttle shaft 3 rotatably provided in a direction perpendicular to the axis XX of the portion 2. A throttle valve 4 is fixed to the throttle shaft 3 so as to be positioned in the throttle body portion 2, and the throttle shaft 4 is opened and closed by rotating the throttle shaft 3 forward and backward by a throttle driving means (not shown). Yes. The cross-sectional shape of the inner surface 2a of the throttle body portion 2 is formed in a substantially circular shape, and the throttle valve 4 is formed in a substantially circular shape in which both axial ends of the throttle shaft 3 are close to the inner surface 2a of the throttle body 2. Has been.
[0022]
On the downstream side of the throttle body portion 2, a diffuser 5 is formed integrally in a series with a tapered surface that expands the inner surface 5a toward the downstream side. The inner surface 5a is formed in a truncated conical surface centered on the axis XX, except for the downstream portions of the throttle shaft 3 near both roots. Further, the upstream side end 5b of the inner surface 5a is set at a position deviated from the axis of the throttle shaft 3 to the downstream side by a predetermined distance L _1. Furthermore, the inclination relative to the axis X-X of the inner surface 5a of the diffuser 5 (expanded) square alpha ₁ is set difficult angle peeling occurs airflow, for example, about 5 to 15 °. In the illustrated example, the angle is set to about 10 °.
[0023]
On the inner surface 5a of the diffuser 5 located on the downstream side of both root portions of the throttle shaft 3, a rectifying convex portion 6 is formed along the axial direction of the diffuser 5, and the total pair of rectifying convex portions 6, 6 are opposed to each other. Are arranged.
[0024]
The rectifying convex portion 6 will be described in more detail. The rectifying convex portion 6 is formed to have a predetermined width around the axis XX of the diffuser 5 passing through the axial center of the throttle shaft 3, and the width is as shown in FIG. As shown in (c), it is formed in a divergent shape in which the upstream side is reduced and the downstream side is enlarged, and the angle α ₂ of both side edges 6a, 6a with respect to the axis XX is approximately the same as the angle α _1. Is set. The angle α ₂ is set to about 10 ° in the illustrated example.
[0025]
Further, the cross-sectional shape of the rectifying convex portion 6 in the direction orthogonal to the axis XX of the diffuser 5 is formed so as to protrude on a substantially arc surface as shown in FIG. 1A, and both side edges 6a thereof. , 6a is a curved surface centered on the inside of the diffuser 5 and is continuous with the inner surface 5a of the diffuser 5. Further, the ridge line 6b on the upstream side of the straightening convex portion 6 is formed on the axial extension line of the inner surface 2a of the throttle body portion 2, that is, flush with the inner surface 2a. The ridgeline 6c is formed in a tapered shape whose downstream side is inclined toward the outer side in the radial direction of the diffuser 5, and further its downstream end portion 6d is expanded in a trumpet shape with a curved surface.
[0026]
As described above, since the upstream end of the ridge line 6b of the rectifying convex portion 6 is flush with the inner surface 2a of the throttle body 2, the upstream end 6e of the rectifying convex portion 6 is the upstream end 5b of the tapered surface 5a of the diffuser 5. And is set at a position shifted by a distance L ₁ downstream from the axis of the throttle shaft 3.
[0027]
In the embodiment shown in the figure, the inner diameter D of the throttle body portion 2 is set to 60 mm, so that the opposing distance L ₂ between the ridges 6 b and 6 b on the upstream side of both the straightening convex portions 6 and 6 is 60 mm. Is set. Further, the distance L ₁ is set to 8 mm.
[0028]
The throttle body 1 with a diffuser is disposed in the intake system with the throttle body 2 on the upstream side and the diffuser 5 on the downstream side.
Next, the intake action of the first embodiment will be described.
[0029]
In the throttle body 1 with a diffuser arranged in the intake system, when the air is sucked in as indicated by the arrow B shown in FIG. 2, it is originally peeled off from the root of the throttle shaft 3 as shown by the oblique lines in FIG. However, by forming the rectifying convex portion 6 as described above, the separation region A is filled with the rectifying convex portion 6 and the separation region becomes a separation region A ₁ indicated by dots in FIG. The separation area A ₁ is reduced as compared with the separation area A shown in FIG.
[0030]
Therefore, the pressure loss due to the separation of the airflow is reduced as compared with the conventional structure, and the pressure recovery efficiency of the diffuser 5 is improved.
Further, since the downstream end portion 6d of the rectifying convex portion 6 is open with a curved surface, the portion 6d has a diffuser function.
[0031]
Further, the rectifying convex portion 6 is not provided on the entire circumference of the diffuser 5 but is partially provided in the downstream portion in the vicinity of the throttle shaft 3, so that the flow area in the diffuser 5 by the rectifying convex portion 6 is reduced. The amount of reduction will not increase much.
[0032]
With respect to the structure of the first embodiment, the pressure recovery efficiency η was measured under the same test conditions as in the prior art. As a result, a value of 43.2% was obtained as shown by η ₂ in FIG. Therefore, the pressure recovery efficiency η ₂ according to the first embodiment is improved by about 6.1 points compared to the pressure recovery efficiency η _{1 of} 37.1% of the conventional structure. As a result, the pressure loss was reduced to reduce the intake loss and the engine output could be improved.
[0033]
3A and 3B show a second embodiment of the present invention, in which FIG. 3A is a view seen from the downstream side of the throttle body 1A with a diffuser, FIG. 3B is a cross-sectional view taken along line YY in FIG. c) is a sectional view taken along line ZZ in FIG.
[0034]
The second embodiment is a modification of the rectifying convex portion 6 in the first embodiment, and the other structures are the same as those in the first embodiment. Therefore, the same reference numerals as those in the first embodiment denote the same parts as in the first embodiment, and a description thereof will be omitted.
[0035]
The rectifying convex portion 6A of the second embodiment has the upstream end 6e at the same position as the first embodiment, and the ridge line 6f downstream from the upstream end 6e is inclined in the axial direction of the diffuser 5 and the downstream end A second narrow portion 6g is formed in the vicinity, and the downstream end portion 6h is a curved surface that is expanded in a trumpet shape from the second narrow portion 6g. The spread angle of the downstream end 6h is set to about 40 °.
[0036]
With such a structure, the distance L ₃ between the second narrow portions 6 g and 6 g facing each other is shorter than the inner diameter D of the throttle body portion 2. Further, the distance L ₄ of the second narrow portion 6g from the throttle shaft 3 is longer than ½ of the inner diameter D of the throttle body portion 2, that is, the downstream side of the throttle valve 4 when the throttle valve 4 is fully opened. It is set so that the second narrow portion 6g is positioned downstream of the end.
[0037]
In the illustrated embodiment, the inner diameter D of the throttle body portion 2 is set to 60 mm, the facing distance L ₃ between the second narrow portions 6g, 6g is set to 50 mm, and the second narrow portion 6g from the axial center of the throttle shaft 3 is set. The distance L ₄ between them is set to 54 mm.
[0038]
In the second embodiment, the second narrowing portion 6g serves as the second peeling point, and the distance between the second peeling point and the first peeling point in the vicinity of the throttle shaft 3 is a long and gently inclined surface. , Suppresses the deceleration of airflow. Further, the air flow separation area in the second embodiment is a separation area A ₂ indicated by dots in FIG. 4, which is further less than the separation area A _{1 in} the first embodiment. Therefore, in the second embodiment, the pressure recovery efficiency is further improved as compared with the structure of the first embodiment.
[0039]
As a result of measuring the pressure recovery efficiency for the structure of the second embodiment under the same test conditions as in the prior art, a value of 47.0% was obtained as indicated by η ₃ in FIG. Therefore, the pressure recovery efficiency η ₃ was improved by 9.9 points from the conventional structure, and further improved by 3.8 points from the first embodiment. From this, according to the second embodiment, the pressure loss can be further reduced as compared with the structure of the first embodiment, the intake loss can be further reduced, and the engine output can be further improved.
[0040]
5A and 5B show a third embodiment of the present invention, in which FIG. 5A is a view seen from the downstream side of the throttle body 1B with a diffuser, FIG. 5B is a cross-sectional view taken along the line YY of FIG. It is ZZ sectional view taken on the line of (a).
[0041]
The third embodiment is a modification of the rectifying projection 6 in the first embodiment, and the other structure is the same as that of the first embodiment. Therefore, the same reference numerals as those in the first embodiment denote the same parts as in the first embodiment, and a description thereof will be omitted.
[0042]
The rectifying convex portion 6B of the third embodiment has the upstream end 6e at the same position as the first embodiment, and the second narrow portion 6i similar to the second narrow portion 6g of the second embodiment is replaced with the first narrow portion 6i. The upstream angle of the second narrow portion 6g in the second embodiment is closer to the upstream side, that is, in the direction of the throttle shaft 3, and the downstream ridge line 6j downstream from the second narrow portion 6i is defined as the downstream end in the second embodiment. This is smaller than the spread angle of the portion 6h.
[0043]
In the illustrated embodiment, the inner diameter D of the throttle body 2 is set to 60 mm, and the distance L ₃ between the second narrow portions 6i, 6i is 50 mm shorter than the inner diameter D of the throttle body 2 as in the second embodiment. The distance L ₅ between the axial center of the throttle shaft 3 and the second narrow portion 6i is set to 28 mm, which is approximately D / 2.
[0044]
According to the third embodiment, as compared with the structure of the second embodiment, the ridgeline 6j downstream from the second narrowing portion 6i, which is the second peeling point, is lengthened and the spread angle downstream thereof is increased. Can be small. Accordingly, the ridgeline 6j is brought close to the angle at which airflow separation is not likely to occur, that is, the spread angle of the inner surface 5a of the diffuser 5, and the separation areas generated before and after the second narrow portion 6i are indicated by dots in FIG. Further, it is possible to make the peeling area A ₃ smaller than that of the second embodiment.
[0045]
As a result of measuring the pressure recovery efficiency for the structure of the third embodiment under the same test conditions as in the prior art, a value of 49.3% was obtained as shown by η ₄ in FIG. Accordingly, the pressure recovery efficiency η ₄ is improved by about 12.2 points from the conventional structure, and further improved by 2.3 points from the second embodiment.
[0046]
Therefore, according to the third embodiment, the pressure loss can be further reduced as compared with the structure of the second embodiment, the intake loss can be further reduced, and the engine output can be further improved.
[0047]
【The invention's effect】
As described above, according to the invention of the present application, compared with the conventional throttle body with a diffuser having the same diameter, the pressure recovery efficiency of the diffuser is increased, the reduction of the intake air amount is reduced, and the engine output is improved. Can be achieved.
[Brief description of the drawings]
1A and 1B show a first embodiment of the present invention, where FIG. 1A is a view seen from the downstream side, FIG. 1B is a cross-sectional view taken along line YY of FIG. 1, and FIG. Z line sectional drawing.
FIG. 2 is a view showing an airflow separation area in the embodiment of FIG. 1;
FIGS. 3A and 3B show a second embodiment of the present invention, where FIG. 3A is a view seen from the downstream side, FIG. 3B is a cross-sectional view taken along line YY of FIG. FIG.
4 is a view showing an airflow separation area in the embodiment of FIG. 3; FIG.
5A and 5B show a third embodiment of the present invention, in which FIG. 5A is a view seen from the downstream side, FIG. 5B is a cross-sectional view taken along line YY of FIG. FIG.
6 is a view showing an airflow separation region in the embodiment of FIG. 5;
FIG. 7 is a graph showing pressure recovery efficiency (pressure loss) of the present invention and a conventional structure.
8A and 8B show a conventional structure, in which FIG. 8A is a view seen from the downstream side, and FIG.
FIGS. 9A and 9B show a separation region of an air flow in a conventional structure, in which FIG. 9A is a cross-sectional view seen from a side surface of a throttle shaft, and FIG.
FIG. 10 is a sectional view schematically showing an apparatus for measuring the pressure recovery efficiency of a throttle body with a diffuser.
[Explanation of symbols]
1, 1A, 1B ... Throttle body with diffuser 2 ... Throttle body 2a ... Inner surface 3 of throttle body 4 ... Throttle shaft 4 ... Throttle valve 5 ... Diffuser 5a ... Riffer inner surface 6, 6A, 6B ... Rectification convex part 6a ... Rectification opposite side edges 6b of the protrusions, 6c, 6f, 6j ... ridge 6g of the rectifying protrusion, 6i ... second constriction _{a 1, a 2, a 3} ... exfoliation region

Claims (5)

A throttle shaft is rotatably inserted in the throttle body portion, a throttle valve is fixed to the throttle shaft, and a diffuser is provided in a series downstream of the throttle body portion, and both sides of the throttle shaft are attached to the inner surface of the diffuser. A throttle body with a diffuser, characterized in that a rectifying convex portion is provided downstream from the vicinity of the root portion. The ridge line of the straightening convex portion is parallel to the axial center of the throttle body from the same surface as the inner surface of the throttle body portion to the downstream side, and the downstream side is expanded in the radial direction. Throttle body with diffuser. The ridge line of the rectifying convex portion is inclined toward the axial center side of the diffuser from the same surface as the inner surface of the throttle body portion, and is expanded radially from the vicinity of the downstream end of the diffuser. Item 1. A throttle body with a diffuser according to item 1. The ridge line of the rectifying convex portion is inclined toward the axial center side of the diffuser from the same surface as the inner surface of the throttle body portion toward the downstream side, and is radially expanded from the vicinity of the upstream end of the diffuser. Item 1. A throttle body with a diffuser according to item 1. The throttle body with a diffuser according to any one of claims 1 to 4, wherein the width of the straightening convex portion as viewed from a plane orthogonal to the axis of the throttle shaft is increased from the upstream side toward the downstream side. .

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