JP2019090381A - Swirl flow generator of intake system - Google Patents

Abstract

To provide a structure capable of suppressing deterioration of dust separation efficiency, or cyclone efficiency, in a case where a swirl flow generation unit and an inner cylinder cannot be arranged coaxially.SOLUTION: A swirl flow generator of an intake system comprises: an outside air introduction duct 3 bent into an elbow shape; a swirl flow generation blade member 6 having a plurality of blades 6b inclined to an axial center of the outside air introduction duct 3; and an outlet duct 7 provided on a downstream side with respect to the swirl flow generation blade member 6, of which an inflow port 7b is opened toward the swirl flow generation blade member 6, and an axial center is eccentric to the swirl flow generation blade member 6. The swirl flow generation blade member 6 is coaxially arranged at a bent part of the outside air introduction duct 3, and an opening end surface of the inflow port 7b of the outlet duct 7 is inclined to the axial center.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a swirl flow generating device provided in an intake system of an internal combustion engine to generate a swirl flow.

  In an intake system of a part of an internal combustion engine, it is practiced to provide a swirling flow generating device, also referred to as a precleaner, upstream of an air cleaner. For example, in Patent Documents 1 and 2, a plurality of fixed type vanes for generating a swirling flow are provided in a duct provided on the upstream side of the air cleaner, and at the downstream side of the vanes, A concentric arrangement of the tubes is disclosed.

  In such a swirling flow generating device, a swirling flow is positively generated in the air before being sucked by the air cleaner, and dust (foreign matter) contained in the suction is separated by a so-called cyclone type centrifugal separation principle, While collecting in the space between the duct and the inner cylinder, only the air of the central portion given the swirling flow is sent out to the air cleaner side through the inner cylinder.

Unexamined-Japanese-Patent No. 2006-274948 JP, 2015-206353, A

  For example, due to the restriction on the arrangement with other devices close to the intake system of the internal combustion engine, it may not be possible to secure a straight shape (straight shape) as the shape of the duct including the swirl flow generating device. In such a case, unlike the ones described in the cited documents 1 and 2, especially when the blade and the inner cylinder can not be arranged on the same axis, the cyclone efficiency which is the original purpose, that is, dust There is a problem that the separation efficiency of

  The present invention has been made focusing on such problems, and in particular, it is possible to use cyclone efficiency even when the vanes functioning as the swirling flow generating unit and the inner cylinder can not be arranged on the same axis. It is an object of the present invention to provide a swirl flow generating device of an intake system capable of suppressing a reduction in the separation efficiency of certain dust.

  The present invention has an outer cylinder bent in an elbow shape, and a plurality of blades arranged to be inclined with respect to the axial center of the outer cylinder between the inner peripheral surface of the outer cylinder and the central portion. A swirling flow generation unit, provided downstream of the swirling flow generation unit in the outer cylinder, and an inflow port is opened toward the swirling flow generation unit inside the outer cylinder, and the axial center is It is a rotational flow generation device of the intake system provided with an inner cylinder which is biased to the above-mentioned rotational flow generation part. In addition, the swirl flow generation unit is disposed at the bending portion of the outer tube bent in an elbow shape so as to have the same axial center as the outer cylinder, and the opening end face of the inlet of the inner cylinder Are inclined with respect to the axial center of the inner cylinder.

  In this case, it is desirable that a space between the outer cylinder and the inner cylinder functions as a space for collecting dust, and a dust outlet communicating with the space is formed as needed.

  As a desirable mode, a portion of the outer cylinder on the downstream side of the swirl flow generation unit in the outer cylinder is larger in diameter than an upstream portion, and an axis of the outer cylinder on the upstream side of the swirl flow generation unit It is assumed that the axial center of the downstream portion with respect to the heart is offset with the axial center of the inner cylinder.

  Similarly, as a desirable mode, the inner circumferential surface of the inner cylinder is formed as a conical shape whose diameter is gradually reduced toward the inlet.

  As a further desirable aspect, the vicinity of the open end face of the inflow port of the inner cylinder is enlarged toward the swirling flow generating portion.

  According to the present invention, even if the axial center of the inner cylinder is offset with respect to the axial center of the swirling flow generation unit, it is possible to suppress the reduction of the dust separation efficiency which is the cyclone efficiency. Therefore, the swirling force obtained by the swirling flow generation unit can be maintained, and the centrifugally separated dust can be efficiently introduced to the space between the outer cylinder and the inner cylinder. As a result, it is possible to contribute to prolonging the life of the air element (air filter) of the air cleaner located downstream of the swirling flow generating device.

1 is a view showing a first embodiment of a swirl flow generating device for an intake system according to the present invention, and a perspective view of a main part of a part of an intake system of an internal combustion engine as viewed from the outside of a case of an air cleaner. The principal part perspective view which looked at a part of intake system shown in Drawing 1 from the inside of the case of an air cleaner. The expanded sectional view which followed the axis line of the external air introduction duct shown to FIG. FIG. 4 is a perspective view showing details of the swirling flow generating blade member shown in FIG. 3; Explanatory drawing for demonstrating the function in the external air introduction | transduction duct shown in FIG. The graph which shows the relationship between the angle ((theta)) of the inlet of the outlet duct and the cyclone efficiency Q (%) in the rotational flow generation apparatus shown in FIG. It is a figure which shows the 2nd Embodiment about the swirling flow production | generation apparatus of the intake system which concerns on this invention, and is an expanded sectional view along the axis line of an external air introduction duct like FIG. Explanatory drawing for demonstrating the function in the external air introduction | transduction duct shown in FIG. The graph which shows the relationship between the aperture ratio (D2 / D1) of the outlet duct and cyclone efficiency Q (%) in the rotational flow generation apparatus shown in FIG.

  1 to 6 show a first specific embodiment for carrying out a swirl flow generating device for an intake system according to the present invention, and in particular, FIG. 1 shows a part of the intake system of an internal combustion engine outside the case of an air cleaner. FIG. 2 is a perspective view of an essential part of the air intake system shown in FIG. 1 as viewed from the inside of a case of an air cleaner. FIG. 3 is an enlarged cross-sectional view along the axis of the outside air introduction duct shown in FIGS.

  As shown in FIGS. 1 and 2, an outside air introduction duct 3 which is a dirty side (inlet side) is connected to a peripheral wall portion of a case 2 having a square shape, for example, of the air cleaner 1. A swirling flow generating device is formed together with a swirling flow generating blade member 6 as a swirling flow generating unit described later contained in the outer air introducing duct 3 as an outer cylinder and an outlet duct 7 as an inner cylinder. In addition, the internal space of case 2 becomes an accommodation space of the air element (air filter) which abbreviate | omitted illustration so that it may be known.

  The outside air introduction duct 3 is generally fitted and connected by inserting one end thereof into the connection flange portion 2a of the case 2 as shown in FIG. It is bent in the shape of a circle. And in order to hold the swirling flow generation blade member 6 mentioned later in this bent shape part, the open air introduction duct 3 in this embodiment is the so-called of the downstream duct 4 which becomes the case 2 side, and the upstream duct 5 It is formed as a two-piece structure.

  The upstream duct 5 has a large diameter fitting flange portion 5a fitted and connected to the swirling flow generating blade member 6 described later, while the downstream duct 4 is fitted and connected to the swirling flow generating blade member 6 And an outlet end 4b fitted and connected to the connection flange 2a on the case 2 side. The downstream duct 4 having the inlet end 4a and the outlet end 4b is itself bent in an elbow shape with a predetermined curvature.

  A swirling flow generating blade member 6 functioning as a swirling flow generating unit is interposed at an intermediate portion in the longitudinal direction of the external air introducing duct 3 including the downstream side duct 4 and the upstream side duct 5. FIG. 4 is an enlarged perspective view of only the swirling flow generating blade member 6. As shown in FIG. 4 and FIG. 4 in addition to FIG. 3, the swirling flow generating blade member 6 has a plurality of blades 6 b which are bent in a spiral shape with respect to the axial center inside the one end of the annular body 6 a. Are arranged radially at equal pitches. The plurality of blades 6b forming the swirling flow generating blade member 6 are gathered at the central portion of the body portion 6a, and each blade 6b protrudes from the body portion 6a toward the inside of the upstream duct 5 The height gradually changes from the central portion toward the outer peripheral side.

  Then, the swirl flow generation blade member 6 is used as a joint member, and from the both sides of the swirl flow generation blade member 6, with the swirl flow generation blade member 6 inside, the fitting flange portion 5a of the upstream duct 5 and the downstream side By fitting and connecting the inflow port side end portions 4a of the ducts 4, the outside air introducing duct 3 bent in a substantially elbow shape is formed. At the same time, the swirling flow generating blade member 6 is interposed in the longitudinal middle portion of the outside air introducing duct 3 composed of the downstream side duct 4 and the upstream side duct 5. Thereby, the upstream duct 5 including at least the fitting flange portion 5a and the swirling flow generating blade member 6 are concentric with each other having the same axial center, and the air flowing in the outside air introducing duct 3 generates the swirling flow By passing the blade member 6, a swirling flow is provided.

  Further, the outlet side end 4b including the outlet 4c of the downstream side duct 4 is formed larger in diameter than the inlet side end 4a fitted to the swirling flow generating blade member 6 as described above . The outlet 4c of the downstream side duct 4 faces the inside of the case 2 of the air cleaner 1, and the outlet 4c is fitted with a straight (straight) outlet duct 7 with a flange portion 7a functioning as an inner cylinder. It is connected. As a result, at the portion of the downstream side duct 4 close to the outlet 4c, the outlet side end 4b and the outlet duct 7 overlap each other to form a substantially double cylindrical structure.

  The diameter of the outlet duct 7 is smaller than the diameter of the outlet end 4 b of the downstream side duct 4, and the large diameter flange portion 7 a formed at one end of the outlet duct 7 is used as the downstream side duct 4. It is fittingly connected in such a way as to be seated at the outlet 4c of the Thereby, the outlet 4c of the downstream side duct 4 is closed. The open end face of the inlet 7 b of the outlet duct 7 is formed obliquely with respect to its own axis, and the outlet duct 7 has the same axial center as the outlet end 4 b of the downstream duct 4. It is formed concentrically.

  Here, as shown in FIG. 3, assuming that the inner peripheral side (the short side of the curvature circumferential length) of the curvature portion of the downstream side duct 4 bent in a substantially elbow shape is the inner corner portion 8, the inflow side end portion The axial center of the outlet end 4b is offset to the inner corner 8 by a predetermined amount with respect to the axial center of 4a. Specifically, the axial center of the upstream duct 5, the axial center of the swirling flow generating blade member 6, and the axial center of the inflow inlet end 4a of the downstream duct 4 coincide with each other. Here, an axial center common to them is referred to as an upstream axial center L1. At the same time, the axis of the outlet end 4b of the downstream duct 4 and the axis of the outlet duct 7 coincide with each other. Here, an axial center common to these is referred to as an axial center L2 on the downstream side. On the other hand, the axial center L2 on the downstream side is offset to the inner corner 8 by a predetermined amount with respect to the axial center L1 on the upstream side.

  Further, as described above, the open end face of the inlet 7b of the outlet duct 7 is formed obliquely with respect to the axis of itself. As for the inlet 7b of the outlet duct 7, as shown in FIG. 3, the trunk length of the portion of the outlet duct 7 near the inner corner 8 of the curved portion of the downstream duct 4 is far from the inner corner 8. As a result, the opening end face of the inflow port 7b of the outlet duct 7 is formed obliquely by forming it so as to be gradually shorter than the length of the portion.

  A void R, which is a portion where the outlet side end 4b of the downstream side duct 4 and the outlet duct 7 overlap each other, and is surrounded by both, is included in the air to which the swirling flow is given as described later. It functions as a space for collecting dust. A short pipe-like dust outlet 9 is formed to project outward at a part of the outlet end 4b of the downstream side duct 4 so as to communicate with the gap R. Further, a flexible dust cup 10 is attached to the outside of the dust outlet 9. Then, as described later, the dust collected in the space R is collected into the dust cup 10 through the dust outlet 9 and then discharged to the outside.

  Due to the mechanism of the dust cup 10, as shown in FIG. 3, the air cleaner 1 is disposed in such a posture that the dust cup 10 is directed downward in the vehicle mounted state. In addition, the dust cup 10 has a sipe (cut) that divides itself into two, and has a known structure in which the sipe opens and closes by a minute external force.

  In the swirl flow generating device of the intake system configured as described above, the air necessary for combustion in the combustion chamber is sucked during the intake stroke of the internal combustion engine, so the external air introduction duct 3 and the air cleaner 1 are used. Outside air is supplied into the combustion chamber.

  At that time, the swirling flow is given in the process of passing the swirling flow generating blade member 6 with the outside air sucked through the upstream duct 5 of the outside air introducing duct 3. That is, the swirling flow is applied in the process of flowing the outside air through the gap between the blades 6 b and 6 b forming the swirling flow generating blade member 6, and the air that has become the swirling flow is the downstream side duct 4 Flow into

  FIG. 5 is an explanatory view for explaining the function of the outside air introduction duct 3 shown in FIG. As described above, if dust (foreign matter) is contained in the air that has become a swirling flow by passing through the swirling flow generating blade member 6, the dust with a large mass (weight) is separated by centrifugal separation by so-called swirling flow On the principle (cyclone effect) of (1), for example, as indicated by a symbol Q1 in FIG. 5, it is driven to the outer peripheral side (the outer peripheral side of the downstream side duct 4 in a cross section perpendicular to the axis) of the downstream side duct 4. Therefore, of the air flowing in the downstream duct 4 as a swirling flow, only the air in the central portion (central portion at the cross section perpendicular to the axis of the downstream duct 4) from which the large dust is removed is the outlet duct 7 It flows into the air cleaner 1 through it.

  Then, in the air cleaner 1, fine dust that could not be removed by the downstream duct 4 is removed by an air element (not shown), and finally, only the air cleaned by passing through the air cleaner 1 It will be supplied to the combustion chamber.

  Also, the large-mass dust driven to the outer peripheral side in the downstream duct 4 by the principle of centrifugal separation by the swirling flow is, as shown by a symbol Q1 in FIG. 5, an outlet end 4b of the downstream duct 4 and The air is collected in the space R between the outlet ducts 7. Then, after being collected in the dust cup 10 through the dust outlet 9 along with the suction pulsation in the suction stroke, the dust cup 10 is opened and closed by the suction pulsation or the vibration accompanying the suction pulsation. Exhausted.

  As described above, according to the swirl flow generation device of the intake system in the present embodiment, the outside air introduction duct 3 as the outer cylinder is bent in a substantially elbow shape, and in the outside air introduction duct 3 The axial center of the outlet duct 7 as the inner cylindrical member to be disposed is biased with respect to the axial center of the swirling flow generating blade member 6 as the swirling flow generating member similarly disposed in the outside air introduction duct 3 To prevent the cyclone efficiency from decreasing due to the application of the swirling flow by inclining the open end face of the inlet 7b of the outlet duct 7 with respect to its own axis even when the two are not on the same axial center Can. It is inferred that the diameter of the downstream side duct 4 is larger than that of the upstream side duct 5 to suppress the decrease in the cyclone efficiency. The definition of cyclone efficiency will be described later.

  Therefore, even if it is not possible to adopt a straight shape as the shape of the outside air introduction duct 3 including the swirl flow generating blade member 6 due to, for example, the restriction on the layout of the intake system, the reduction of the cyclone efficiency is suppressed. Become able to achieve the purpose.

  Here, in the present embodiment, as shown in FIG. 5 for the outlet duct 7 shown in FIG. 3, the inclination angle θ of the open end face of the inflow port 7b is set to 10 degrees. Therefore, here, the dust separation efficiency, which is the degree to which dust can be collected, collected and discharged by the principle of centrifugal separation (so-called cyclone effect) by the application of swirling flow, is defined as cyclone efficiency Q (%). Do. Furthermore, in addition to the case where the inclination angle θ is 10 degrees, when the inclination angle θ is 5 degrees, and the inclination angle θ is 0 degrees (the open end face of the inlet 7 b is with respect to the axis of the outlet duct 7 And the cyclone efficiency Q (%).

  As a result, the cyclone efficiency Q (%) was 43% when the inclination angle θ was 10 degrees, 38% when the inclination angle θ was 5 degrees, and 30% when the inclination angle θ was 0 degrees. What these results were graphed is shown in FIG. The cyclone efficiency Q (%) is represented by the following formula (1).

Cyclone efficiency Q (%) = B ÷ (A-B) x 100 ... (1)
However, A is the amount of dust input, and B is the amount of dust collected and discharged by the cyclone effect.

  As is clear from FIG. 6, there is a proportional relationship between the inclination angle θ and the cyclone efficiency Q (%), and in the case of the inclination angle θ = 10 degrees, the cyclone efficiency Q (%) is It turned out to be the highest. In this case, when the inclination angle θ is 0 degree, the outlet duct 7 has a simple straight shape, so the presence of the outlet duct 7 becomes the resistance of the swirling flow indicated by a symbol Q1 in FIG. It is estimated that the efficiency Q (%) is the lowest.

  As described above, according to the present embodiment, the dust separation efficiency can be obtained even if the axial center of the outlet duct 7 as the inner cylinder is biased with respect to the axial center of the swirling flow generating blade member 6 as the swirling flow generation unit. It is possible to suppress the decrease in cyclone efficiency, which is Therefore, the swirling force obtained by the swirling flow generating blade member 6 can be maintained, and the centrifugally separated dust can be efficiently introduced to the gap R between the downstream duct 4 and the outlet duct 7. As a result, it is possible to contribute to prolonging the life of the air element (air filter) of the air cleaner 1 located downstream of the outlet duct 7.

  7 to 9 show a second embodiment of the swirl flow generating device for an intake system according to the present invention. In the description of the second embodiment, the same reference numerals as in FIG. 3 denote the same parts as in FIG. 3, and a duplicate description will be omitted.

  In the second embodiment shown in FIG. 7, the shape of the outlet duct 12 functioning as an inner cylinder is different from that shown in FIG. The outlet duct 12 shown in FIG. 7 is formed in a conical shape so that the diameter thereof gradually decreases toward the swirling flow generating blade member 6. More specifically, the flow of the air to which the swirling flow is given by passing the swirling flow generating blade member 6 passes from the downstream side duct 4 to the inside of the case 2 of the air cleaner 1 through the outlet duct 12. In consideration of flow smoothness, as shown in FIG. 7, in addition to the outlet duct 12 being formed in a conical shape, the circumferential wall portion of the conical outlet duct 12 has a convex shape directed inward. It is formed as a smooth curved shape or an arc shape which becomes

  The diameter-increased portion 11 is bent so as to expand the diameter toward the swirling flow generating blade member 6 in the vicinity of the opening end face of the inlet 12b of the outlet duct 12, and is formed in a so-called bellmouth shape.

  FIG. 8 is an explanatory view for explaining the function of the outside air introduction duct 3 shown in FIG. As shown in FIG. 8, the inclination angle θ of the open end face of the inlet 12 b of the outlet duct 12 is set to 10 degrees as in FIG. 3. Furthermore, when focusing on the aperture ratio of the sizes of the inlet 12b and the outlet 12c of the outlet duct 12, the aperture ratio D2 / D1 of the diameter D1 of the inlet 12b to the diameter D2 of the outlet 12c is set to 1.4. It is done.

  In the first embodiment shown in FIG. 3, as described above with reference to FIG. 6, when the inclination angle θ of the opening end face of the inlet 7 b of the outlet duct 7 is set to 10 degrees, the inclination is It has been found that the cyclone efficiency Q (%) is improved as compared to the case where the angle θ is smaller than 10 degrees.

  On the other hand, in the first embodiment shown in FIG. 3, the outlet duct 7 has a straight shape (straight shape) as described above. In this case, when the air flow imparted with the swirling flow by passing the swirling flow generating blade member 6 is directed to the outlet duct 7, the entire opening area of the outlet duct 7 is not effectively utilized, as shown in FIG. It has been found that, as indicated by symbol Q2, the downstream duct 4 tends to pass through in a state biased to a portion near the inner corner portion 8. And it is presumed that this flow bias tendency has some effect on the cyclone efficiency Q (%) mentioned above.

  On the other hand, in the second embodiment shown in FIG. 7, the outlet duct 12 is formed in a conical shape, and the diameter in the vicinity of the inflow port 12b is expanded, and in the so-called bellmouth shape. It has become. Therefore, the deviation of the air flow as described above is eliminated, and as shown by reference numeral Q3 in FIG. 8, the entire opening area of the outlet duct 12 is effectively utilized, thereby further improving the cyclone efficiency. It has been found.

  Further, when the flow analysis around the outlet duct 12 shown in FIG. 7 is performed, the swirling flow generated by passing the swirling flow generating blade member 6 is reversely rotated at the inlet of the dust outlet 9. It turned out that it collides with the swirling flow, and it results in the result that the flow velocity drops rapidly at the relevant position. Thereby, it is considered that a flow field in which dust tends to descend toward the dust outlet 9 is formed, and it is presumed that the cyclone efficiency contributes to further improvement.

  In the present embodiment, for the outlet duct 12 shown in FIG. 7, as shown in FIG. 8, the inclination angle θ of the open end face of the inflow port 12 b is set to 10 degrees as in the first embodiment. There is. Furthermore, when focusing on the aperture ratio between the inlet 10b and the outlet 12c of the outlet duct 12, the aperture ratio D2 / D1 between the diameter D1 of the inlet 12b and the diameter D2 of the outlet 12c is set to 1.4. doing.

  Therefore, after setting the inclination angle θ of the opening end face of the inlet 12b of the outlet duct 12 to 10 degrees, the aperture ratio D2 / D1 is set to 1.4, and the aperture ratio D2 / D1 is set to 1.2. The cyclone efficiency Q (%) was measured in the same manner as in the first embodiment described above for each of the cases where the aperture ratio D2 / D1 was 1.

  As a result, the cyclone efficiency Q (%) is 55% when the aperture ratio D2 / D1 is 1.4, 52% when the aperture ratio D2 / D1 is 1.2, and 1 when the aperture ratio D2 / D1 is 1. To 43%. What these results were graphed is shown in FIG. In addition, cyclone efficiency Q (%) is represented by Formula (1) similarly to the above.

  As is clear from FIG. 9, there is a proportional relationship between the above-mentioned aperture ratio D2 / D1 and the cyclone efficiency Q (%), and the cyclone efficiency is obtained when the aperture ratio D2 / D1 is 1.4. It turned out that Q (%) becomes the highest.

  6 and 9, the inclination angle θ of the open end face of the inlet 12b of the outlet duct 12 is 10 degrees, and the above aperture ratio D2 / D1 is 1.4. It was found that the cyclone efficiency Q (%) is the highest when the

  As described above, according to the present embodiment, the cyclone efficiency can be further improved as well as the same effect as the first embodiment can be obtained.

3 ... Outside air introduction duct (outer cylinder)
4 ... downstream duct 5 ... upstream duct 6 ... swirl flow generation blade member (swirl flow generation section)
6b ... vane 7 ... outlet duct (inner cylinder)
7b: Inlet 9: Dust outlet 11: Expanded diameter portion 12: Outlet duct (inner cylinder)
12b ... inlet

Claims (5)

An outer tube bent in an elbow shape,
A swirl flow generation unit having a plurality of blades arranged to be inclined with respect to the axial center of the outer cylinder between the inner circumferential surface and the central portion of the outer cylinder;
The outer cylinder is provided on the downstream side of the swirl flow generation unit, the inflow port is opened toward the swirl flow generation unit inside the outer cylinder, and the axial center is open to the swirl flow generation unit. The inner cylinder is biased against
Equipped with
The swirling flow generating unit is disposed at the bending portion of the elbow-shaped outer cylinder so as to have the same axial center as the outer cylinder.
An inlet end face of an inlet of the inner cylinder is inclined with respect to an axial center of the inner cylinder. The diameter of the portion of the outer cylinder downstream of the swirling flow generating portion is larger than that of the upstream portion,
The axial center of the downstream side portion is offset with the axial center of the inner cylinder with respect to the axial center of the upstream side portion of the outer cylinder with respect to the swirl flow generation unit. Swirling flow generation device for the intake system of   The swirl flow generating device for an intake system according to claim 1 or 2, wherein the inner peripheral surface of the inner cylinder is formed as a conical shape whose diameter decreases gradually toward the inflow port.   The swirl flow generation device for an intake system according to claim 3, wherein a diameter of the vicinity of the opening end face of the inflow port of the inner cylinder is expanded toward the swirl flow generation unit.   5. A swirl flow generating device for an intake system according to claim 4, wherein a dust outlet is formed at a position corresponding to the vicinity of the inlet of the inner cylinder in the outer cylinder.

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