JP2009019613A - Intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device for an internal combustion engine capable of suppressing cooling loss while suppressing weakening of a swirl. <P>SOLUTION: The intake device includes an intake port 5 for making a tangential flow Ft flow out in the direction along the inner periphery of a cylinder 2 of the internal combustion engine by leading air toward the cylinder 2, and by using the tangential flow Ft made to flow out by the intake port 5, the swirl Fsw can be formed in the cylinder 2. The intake device is provided with a cylinder member 10 having a blade part 12A extending while twisting about the same direction as the direction of a rotational component f2 so that the tangential flow Ft includes the rotational component f2 around the axis extending in the advancing direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intake device for an internal combustion engine capable of forming a swirl in a cylinder of the internal combustion engine.

  There is an internal combustion engine intake device provided with an auxiliary intake port that opens to a cylinder head adjacent to an intake port of a diesel engine (Patent Document 1). This intake device introduces a longitudinal flow into the cylinder from the auxiliary intake port when a swirl is generated in the cylinder, and increases the turbulent energy of the intake air by mixing the swirl and the longitudinal flow. In addition, Patent Documents 2 and 3 exist as prior art documents related to the present invention.

JP-A-4-47124 Japanese Patent Laid-Open No. 11-257077 Japanese Patent Laid-Open No. 2002-30937

  If the swirl formed in the cylinder becomes stronger, the flow rate increases, and therefore the amount of heat radiation from the wall surface that contacts the swirl, such as the inner peripheral surface of the cylinder or the top surface of the piston, increases, resulting in an increase in cooling loss. . Further, if the swirl is simply mixed with the swirl like the intake device of Patent Document 1, the swirl in the cylinder may interfere with the swirl introduced from the auxiliary intake port and the swirl may be weakened.

  Accordingly, an object of the present invention is to provide an intake device for an internal combustion engine that can suppress an increase in cooling loss while suppressing weakening of a swirl.

  An intake device for an internal combustion engine according to the present invention includes an intake port that causes a tangential flow in a direction along an inner periphery of the cylinder to flow into the cylinder by guiding air toward the cylinder of the internal combustion engine, and the intake port includes In an intake device of an internal combustion engine that can form a swirl in the cylinder using the tangential flow that has flowed out, the air introduced by the intake port so that the tangential flow has a rotational component around an axis extending in the traveling direction. On the other hand, the above-described problem is solved by providing a rotation component applying means for applying a rotation component around the same direction as the rotation component.

  According to this intake device, since the tangential flow along the inner periphery of the cylinder has a rotational component around the axis extending in the traveling direction, the turbulence is generated near the inner peripheral wall surface of the cylinder, and the flow velocity in the vicinity thereof decreases. Therefore, the boundary layer between the swirl formed by the development of the tangential flow and the cylinder wall surface becomes thick. Thereby, the heat radiation from the wall surface of the cylinder can be suppressed. Since a rotational component is given to the air guided by the intake port, the swirl formed in the cylinder does not interfere with other airflows. Moreover, the flow rate is slow only in a region close to the wall surface. Therefore, it is possible to suppress an increase in cooling loss while suppressing weakening of the swirl.

  As one aspect of the present invention, the intake port generates a swirl flow for letting the swirl flow swirling in the same direction as the rotation direction of the swirl and the tangential flow generation region for letting the tangential flow flow out into the cylinder. The swirl generation port is formed in the same port so that the region is adjacent to the upper and lower sides in the height direction of the cylinder, and the rotation component applying means is limitedly provided in the tangential flow generation region. (Claim 2). According to this aspect, since the range in which the rotation component applying means is provided is limited to the tangential flow generation region, the rotation component applying means is less exposed to the air than in the case where the rotation component applying means is provided in the entire cross section of the intake port. There will be less influence. Thereby, since the flow velocity of the air affected by the rotation component applying means becomes relatively high, the strength of the swirling component of the tangential flow that flows out from the intake port can be increased.

  There is no particular limitation on the rotation component applying means, and it is sufficient that the required rotation component can be applied to the air. For example, as the rotation component applying means, the twisting about the same direction as the rotation component that protrudes inward from the inner surface side of the intake port and that the tangential flow has in the direction in which air is guided at the intake port. However, a spiral protrusion that extends may be provided (claim 3). According to this aspect, since air passing through the intake port travels along the spiral protrusion, a rotation component in a predetermined direction can be given to the air. In this aspect, the spiral protrusion may be curved so that a cross section in the short side direction becomes concave toward the twist direction (claim 4). In this case, since it becomes easier to catch air, a swirl component can be efficiently given to the air.

  Further, as one aspect of the present invention, the intake port includes an immovable portion formed in a cylinder head of the internal combustion engine, and an axis around which the spiral protrusion is provided and extends in a direction in which the air is guided. And a rotation drive unit that is supported by the cylinder head in a state of being rotatable relative to the unit, and further includes a rotation drive unit that can rotate the rotation unit about the same direction as the twist direction of the spiral protrusion. (Claim 5). According to this aspect, when the rotating portion rotates in the same direction as the twist direction of the spiral protrusion, a larger rotational component can be given to the air guided by the intake port.

  There is no particular limitation on the configuration of the rotation driving means. For example, the rotating unit can be rotated using an electric motor. The internal combustion engine includes an intake valve that opens and closes the intake port, and valve operating means that drives the intake valve to open and close, and the rotational drive means is configured to cause the valve operating means to open the intake valve. A transmission mechanism may be provided that converts the movement of the above into a movement for rotating the rotating part and transmits the converted movement to the rotating part (Claim 6). In this case, since the rotary part is rotationally driven using the valve operating means, it is not necessary to separately prepare a drive source dedicated to rotational drive for the rotary part. Thereby, an increase in the number of parts can be suppressed. In addition, since the valve operating means rotates the rotating part using the movement of opening the intake valve, the valve opening period of the intake valve and the rotating period of the rotating part can be easily synchronized.

  As described above, according to the present invention, since the tangential flow along the inner periphery of the cylinder has a rotational component around the axis extending in the traveling direction, turbulence occurs near the inner peripheral wall surface of the cylinder, and the flow velocity in the vicinity thereof And the boundary layer between the swirl and the cylinder wall surface becomes thicker. Thereby, the heat radiation from the wall surface of the cylinder can be suppressed. In addition, since the swirl component is given to the air guided by the intake port, the swirl formed in the cylinder does not interfere with other airflows. Therefore, it is possible to suppress an increase in cooling loss while suppressing weakening of the swirl. As a result, it is possible to suppress an increase in cooling loss without impairing the mixing and diffusing effect of the fuel by the swirl, so that low fuel consumption and low smoke combustion becomes possible.

(First form)
FIG. 1 is a plan view schematically showing a main part of an internal combustion engine to which an intake device according to an embodiment of the present invention is applied. In this figure, there are portions where the inner surfaces of passages, holes and the like are illustrated by outlines for easy understanding. The internal combustion engine 1 shown in FIG. 1 is configured as an in-line diesel engine formed in a cylinder block 3 such that a plurality (only one is shown) of cylinders 2 are arranged in one direction. An intake passage 4 for sucking air is connected to the cylinder 2, and the intake passage 4 includes two intake ports 5 and 6 for guiding air to each cylinder 2. These intake ports 5 and 6 are formed in a cylinder head 7 that closes the opening of the cylinder 2. Openings of the intake ports 5 and 6 are opened and closed by an intake valve 8. The cylinder 2 is connected to an exhaust passage for guiding exhaust, but the illustration is omitted.

  One intake port 5 is configured as a so-called tangential port, and the intake port 5 guides air toward the cylinder 2, thereby causing a tangential flow Ft along the circumferential direction of the cylinder 2 to flow out. The other intake port 6 is configured as a helical port. The intake port 6 guides air to the cylinder 2 to cause the swirling flow Fr swirling in the circumferential direction of the cylinder 2 to flow out. In the intake stroke, the tangential flow Ft and the swirl flow Fr flow out from the intake ports 5 and 6, respectively, and thus the swirl Fsw is formed in the cylinder 2 using these flows. As is well known, the swirl Fsw is a flow swirling in a plane that intersects the center line of the cylinder 2 along the inner peripheral surface of the cylinder 2. Note that the presence of the intake port 6 configured as a helical port is not essential for the formation of the swirl Fsw. Therefore, the swirl Fsw can be formed even if the intake port 6 is changed to another form or omitted.

  The intake port 5 includes a cylindrical member 10 that functions as a rotational component applying means disposed on the upstream side thereof. The cylinder member 10 is configured as a separate part from the cylinder head 7. A mounting hole 7 a for fitting the cylinder member 10 is formed in the cylinder head 7, and the mounting hole 7 a has an inner diameter that is larger than the inner diameter of the intake port 5 by the thickness of the cylindrical member 10. The cylindrical member 10 functions as a part of the intake port 5 by being fitted in the mounting hole 7a in a non-rotatable state.

  2 to 7 show details of the cylindrical member 10 shown in FIG. 2 is a front view of the cylindrical member 10, FIG. 3 is a view showing a state seen from the direction of arrow III in FIG. 2, FIG. 4 is a view showing a state seen from the direction of arrow IV in FIG. FIG. 7 is a cross-sectional view taken along lines VV, VI-VI, and VII-VII in FIG.

  As shown in these drawings, the cylindrical member 10 is formed in a cylindrical shape, and four blade portions 12A to 12D extending spirally are provided at equal intervals in the circumferential direction on the inner peripheral surface 10a. Each blade part 12A-12D protrudes inward from the inner peripheral surface 10a of the cylindrical member 10, and extends while twisting clockwise in the direction in which air is guided (the direction from right to left in FIG. 2). . Moreover, each blade part 12A-12D is curving so that the cross section (cross section) of the transversal direction may become concave toward a twist direction. In the illustrated form, the twist pitch is set such that each blade portion 12A to 12D is twisted once by rotating from the inlet side end portion 10b of the cylindrical member 10 to the outlet side end portion 10c. Thus, when the cylindrical member 10 is fitted into the cylinder head 7 and the intake port 5 is configured, the air passing through the intake port 5 flows along the blade portions 12A to 12D, as is apparent from FIGS. proceed. Therefore, a swirl component that rotates in the same direction as the twist direction, that is, clockwise in the direction in which the air is guided, is given to the air guided through the intake port 5.

  As a result, as shown in FIG. 1, the tangential flow Ft that flows out from the intake port 5 has a tangential component f1 and a rotational component f2 that is clockwise with respect to the traveling direction. That is, since the tangential flow Ft has a rotation component f2 around the axis extending in the traveling direction in addition to the tangential component f1, at least a part of the tangential flow Ft draws a spiral. For this reason, turbulence is generated in the vicinity of the inner peripheral wall surface of the cylinder 2, and the flow velocity in the vicinity thereof is reduced. 8 and 9 schematically show the flow state near the inner peripheral wall surface of the cylinder. FIG. 8 shows the flow velocity distribution near the inner peripheral wall surface in the initial outflow of the tangential flow Ft, and FIG. 9 shows the tangential flow developed. It is explanatory drawing which each showed the flow-velocity distribution of the inner peripheral wall surface in the state in which the swirl Fsw was produced | generated. In FIG. 9, the flow velocity distribution of a comparative example using a normal intake port is indicated by a broken line.

  As shown in FIG. 8, at the initial outflow of the tangential flow Ft, the flow of the inner peripheral wall surface is disturbed by the influence of the rotation component f1, and the flow velocity is lowered at a position near the wall surface. Thereafter, the tangential flow Ft and the swirl flow Fr of the intake port 6 shown in FIG. 1 are combined to form a swirl Fsw. The flow velocity distribution of the swirl Fsw is affected by the turbulence in the initial outflow of the tangential flow Ft, and as shown in FIG. 9, the flow velocity only at a position close to the inner peripheral wall surface becomes slower than the comparative example. Thereby, since the boundary layer between the swirl Fsw and the inner peripheral wall surface of the cylinder 2 is thickened, heat radiation from the inner peripheral wall surface can be suppressed. Since a rotational component is given to the air guided by the intake port 5, the swirl Fsw formed in the cylinder 2 does not interfere with other airflows. Moreover, the flow rate is slow only in the region close to the inner peripheral wall surface. Therefore, it is possible to suppress an increase in cooling loss while suppressing weakening of the swirl. The present embodiment is not limited to the inner peripheral wall surface of the cylinder 2, and the same effect is obtained with respect to the piston top surface and the like existing in the cylinder 2.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second mode is characterized in that the above-described cylindrical member 10 is rotated with respect to the cylinder head 7. The basic configuration of the internal combustion engine 1 is the same as that shown in FIG. FIG. 10 shows an outline of a mechanism for rotating the cylindrical member, and FIG. 11 shows a cross section taken along line XI-XI in FIG. As shown in these drawings, the internal combustion engine 1 is provided with a rotation drive mechanism 20 that functions as a rotation drive means in order to rotate the cylindrical member 10 with respect to the cylinder head 7. The cylinder member 10 is supported by the cylinder head 7 via a bearing 13 in a state of being rotatable around an axis Ax extending in a direction in which air is guided. Thereby, the cylinder member 10 functions as a rotating part constituting a part of the intake port 5, and the remaining part of the intake port 5 functions as a non-moving part.

  The rotation drive mechanism 20 is configured such that the valve mechanism (valve drive means) 15 of the internal combustion engine 1 can rotationally drive the cylindrical member 10 using a motion for opening the intake valve 8. The rotation drive mechanism 20 uses the rotation of the camshaft 16 of the valve operating mechanism 15 as a drive source, and the power is transmitted to the cylindrical member 10 by the transmission mechanism 21. As is well known, the camshaft 16 has an intake cam 16a for opening and closing the intake valve 8, and is driven by the rotation of the crankshaft of the internal combustion engine 1.

  The transmission mechanism 21 rotates integrally with the camshaft 15 and has a cylinder member rotation cam 22 having an operating angle that overlaps the operating angle of the intake cam 16 and is interposed between the cam 22 and the cylinder member 10. And an intermediate mechanism 23. The intermediate mechanism 23 is coupled to the cylinder member 10 and a cam follower 24 that is slidably supported by the cylinder head 7 in contact with the cam surface of the cam 22 and pressed against the cam 22 side by a return spring 26. Arm 25. The cam follower 24 is formed with a guide groove 24a extending in a direction orthogonal to the direction of movement, and the arm 25 is provided with a slide member 25a that slides in the guide groove 24a.

  With the above configuration, the rotation drive mechanism 20 can rotate the cylindrical member 10 in the direction of the solid line arrow in FIG. 10 according to the opening operation of the intake valve 8 by the intake cam 16. That is, the rotation drive mechanism 20 can be rotated in the same direction as the twist direction of the blade portions 12 </ b> A to 12 </ b> D of the cylindrical member 10. Note that after the intake valve 8 is closed, the rotation direction of the cylindrical member 10 is reversed in the direction of the broken line arrow in FIG. The timing relationship between the opening operation of the intake valve 8 and the rotating operation of the cylindrical member 10 can be adjusted by appropriately setting the profile of the cylindrical member rotating cam 22.

  According to the second mode, the cylinder member 10 can be rotated in the same direction as the twist direction of the blade portions 12A to 12D in synchronization with the intake stroke of the internal combustion engine 1, and therefore, the air guided by the intake port 5 A larger rotational component can be provided.

(Third form)
Next, a third embodiment of the present invention will be described with reference to FIGS. This mode is characterized by the configuration of the intake port for allowing the tangential flow Ft to flow out and the arrangement of the cylindrical member as the rotation component applying means for applying the rotation component. Hereinafter, the characteristic points of the third embodiment will be mainly described, and the common points with the above-described embodiments will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted.

  FIG. 12 is a plan view schematically showing a main part of the internal combustion engine to which the intake device according to the third embodiment is applied. As shown in this figure, the internal combustion engine 1 is provided with an intake port 31 configured as a swirl generation port capable of generating a tangential flow Ft and a swirl flow Fr in the same port. The intake port 31 includes a cylindrical member 36 having a smaller size than the cylindrical member 5 according to the above-described form as a part thereof. The cylindrical member 36 is fitted in a mounting hole 7 a ′ formed in the cylinder head 7 in a non-rotatable state. The configuration of the cylindrical member 36 is the same as that shown in FIGS.

  FIG. 13 shows details of the intake port 31, and a plan view seen from above the cylinder 2 and sectional views a to d are shown. Note that FIG. 13 does not show the cylindrical member 36 because the basic function of the intake port 31 is mainly described. The intake port 31 includes an opening 32 that opens to the cylinder 2, a helical portion 33 that continues to the opening 32 while being curved around the stem portion of the intake valve 8, and an upstream side (away from the cylinder 2) of the helical portion 33. And an introduction portion 34 connected to the side).

  As shown in each sectional view taken along line aa and bb in FIG. 13, the introduction part 34 has an upper layer region 34 a located on the upper side in the vertical direction of the cylinder 2 and a lower layer region 34 b located on the lower side. . These upper layer region 34 a and lower layer region 34 b are formed in the intake port 31 so as to be adjacent to each other in the vertical direction with respect to the height direction of the cylinder 2. The introduction portion 34 is configured such that the lateral width W1 of the upper layer region 34a is narrower than the lateral width W2 of the lower layer region 34b, and the difference between these lateral widths gradually increases as the helical portion 33 is approached. That is, the upper layer region 34 a is configured to be gradually narrowed as it approaches the helical portion 33. As shown in the cross-sectional views taken along line cc and line dd in FIG. 13, the helical portion 33 is configured such that the height h in the vertical direction of the cylinder 2 gradually decreases in the process of bending toward the opening portion 32. It is configured.

  According to the intake port 31, the air guided thereto passes through the lower layer region 34 b of the introducing portion 34, whereby the tangential flow Ft flows out into the cylinder 2, and the air continues to the upper layer region 34 a of the introducing portion 34 and the following. The swirl flow Fr flows out into the cylinder 2 by passing through the helical portion 33. As a result, as shown in FIG. 12, the swirl Fsw is generated in the cylinder 2 while ensuring the required intake air flow rate. That is, the lower layer region 34b in the illustrated form corresponds to the tangential flow generation region according to the present invention, and the upper layer region 34a corresponds to the swirl flow generation region according to the present invention.

  As shown in FIG. 12, the cylindrical member 36 of this embodiment is limitedly provided in the lower layer region 34b described above. That is, the cylindrical member 36 functions as a part of the intake port 31 by being disposed in the lower layer region 34b so as not to impair the function of the upper layer region 34a. Thereby, it can restrict to the air which passes the lower layer area | region 34b, and can give the rotation component of the same direction as each form mentioned above. Since the dimension of the cylindrical member 36 is smaller than that of the configuration of FIG. 1 and the flow velocity is increased, the strength of the swirl component f2 of the tangential flow Ft that flows out from the intake port 31 can be increased as compared with the configuration of FIG.

  The present invention is not limited to the above embodiments, and can be implemented in various forms. The form of the intake port according to the present invention is not limited to the form shown in the drawings, and any shape can be used as long as it can flow a tangential flow. For example, the intake port 5 shown in FIG. 1 can be replaced with a known helical port. In addition, the intake port is arranged next to the intake port according to the present invention and its form is arbitrary. Therefore, this intake port may be omitted, and this intake port can be implemented in various forms.

  The form of the rotation component applying means is arbitrary, and need not be a separate component from the cylinder head 7. For example, a spiral protrusion equivalent to the blade portions 12A to 12D shown in FIGS. 2 to 7 may be integrally provided on the inner surface of the intake port. Moreover, these blade parts 12A-12D are only examples of a spiral protrusion. For example, it can also be implemented in a linear form without the cross section of the spiral protrusion being curved. In addition, as shown in the figure, when it is curved so as to be concave with respect to the twisting direction, air can be easily captured, so that a swirl component can be efficiently given to the air. The number of spiral protrusions is arbitrary and may be one. Further, the protruding amount can be determined as appropriate. For example, by increasing the protrusion amount, the intake port can be partitioned by a spiral protrusion.

  Further, the rotation driving means is not limited to being mechanically realized as in the second embodiment. Therefore, for example, the rotation driving means can be implemented by an electric motor. When the electric motor is used, there is an advantage that the timing for rotating the rotating portion can be arbitrarily set by the operation control of the electric motor. Therefore, it is possible to easily realize changing the strength of the rotation component according to the operating state of the internal combustion engine 1.

  In the third embodiment, the cylindrical member 36 is provided so as not to rotate with respect to the cylinder head 7. However, the cylindrical member 36 is mounted rotatably with respect to the cylinder head 7, and this is the same mechanism as in the second embodiment. Alternatively, it can be rotated using an electric motor or the like.

The top view which showed typically the principal part of the internal combustion engine to which the intake device which concerns on one form of this invention was applied. The front view which showed the detail of the cylinder member of FIG. The figure which showed the state seen from the direction of arrow III of FIG. The figure which showed the state seen from the direction of arrow IV of FIG. Sectional drawing regarding the VV line of FIG. Sectional drawing regarding the VI-VI line of FIG. Sectional drawing regarding the VII-VII line of FIG. Explanatory drawing which showed the flow-velocity distribution near the inner peripheral wall surface in the outflow early stage of a tangential flow. It is explanatory drawing shown respectively. Explanatory drawing which showed the flow-velocity distribution of the inner peripheral wall surface in the state where the tangential flow developed and the swirl was generated. The figure which showed the outline of the mechanism which rotates a cylinder member. Sectional drawing regarding the XI-XI line of FIG. The top view which showed typically the principal part of the internal combustion engine to which the intake device which concerns on a 3rd form was applied. The figure which showed the detail of the intake port shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 5 Intake port 7 Cylinder head 10 Cylindrical member (Rotation component provision means, rotation part)
12A-12D Blade part (spiral protrusion)
15 Valve mechanism (valve mechanism)
20 Rotation drive mechanism (rotation drive means)
21 Transmission mechanism 31 Intake port (swirl generation port)
36 Tube member (rotation component applying means, rotating part)
34a Upper layer region (swirl flow generation region)
34b Lower layer region (tangential flow generation region)
Ax Axis Ft that extends in the direction in which the air is guided Tangent flow Fsw Swirl f2 Rotational component

Claims (6)

An intake port for flowing out a tangential flow in a direction along the inner periphery of the cylinder by introducing air toward the cylinder of the internal combustion engine into the cylinder, and using the tangential flow discharged by the intake port; In an intake device for an internal combustion engine that can form a swirl in a cylinder,
Rotation component applying means for applying a rotation component around the same direction as the rotation component of the tangential flow to the air guided by the intake port so that the tangential flow has a rotation component around an axis extending in the traveling direction. An intake device for an internal combustion engine, comprising: The intake port has a tangential flow generation region for letting out the tangential flow and a swirl flow generation region for letting a swirling flow swirling in the same direction as the rotation direction of the swirl into the cylinder. It is configured as a swirl generation port formed in the same port so as to be adjacent vertically in the vertical direction,
2. The intake device for an internal combustion engine according to claim 1, wherein the rotation component applying unit is provided in a limited manner in the tangential flow generation region.   As the rotation component applying means, it protrudes inward from the inner surface side of the intake port and extends while twisting around the same direction as the rotation component of the tangential flow toward the direction in which air is guided at the intake port. The intake device for an internal combustion engine according to claim 1, wherein a spiral protrusion is provided.   The intake device for an internal combustion engine according to claim 3, wherein the spiral protrusion is curved so that a cross section in a short direction thereof becomes concave toward a twist direction. The intake port is a state in which the stationary part formed in the cylinder head of the internal combustion engine and the spiral protrusion and the axis that extends in the direction in which the air is guided can rotate relative to the stationary part. And a rotating part supported by the cylinder head,
5. The intake device for an internal combustion engine according to claim 3, further comprising a rotation driving unit capable of rotating the rotating unit in the same direction as a twist direction of the spiral protrusion. The internal combustion engine includes an intake valve that opens and closes the intake port, and valve operating means that drives the intake valve to open and close,
The rotation driving means includes a transmission mechanism that converts a movement for opening the intake valve by the valve operating means into a movement for rotating the rotation section and transmits the movement to the rotation section. The intake device for an internal combustion engine according to claim 5.

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