JP2006016993A - Air intake system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air intake system of a vehicle capable of making clear sound by preventing unclear intake noise. <P>SOLUTION: This air intake system of an internal combustion engine has an intake air introduction port 10 to introduce intake air and a volumetric part 1 to which a plurality of branch parts 2 to 5 respectively communicated to an air intake port of an engine and acoustic control parts 6 to 9 applied with dimple work are respectively provided at least on parts facing against branch openings 11 to 14 on an internal wall surface of the volumetric part 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle intake device, and more particularly to a structure of an intake device that improves intake sound to a clear sound quality.

  As a cause of deteriorating the sound quality of the intake sound of the vehicle, the intake sound itself becomes cloudy due to the fact that the air flow noise is generated in the intake passage in addition to the intake sound and the path length of the intake flow varies from cylinder to cylinder It is known to become a sound.

  In a four-cycle engine, operations such as opening and closing of the intake valve are performed once for two rotations of the crankshaft, so that the intake noise includes a 0.5th order component with respect to the rotation of the crankshaft.

  In general, in a multi-cylinder engine, intake air that has passed through a throttle chamber is distributed from a collector tank to an intake port of each cylinder. However, the passage length from the collector tank inlet to the engine side end of each cylinder branch varies depending on the layout constraints of the engine room and the characteristics such as output.

  For this reason, some of the above 0.5th order components may be synthesized and emphasized. When the sounds of the 0.5th order component overlap in this way, the intake sound becomes muddy.

  For example, the air flow noise must be bent greatly in the direction of the intake air flow due to the layout restrictions in the engine room, and the bent portion, especially the inner surface with the smaller radius of curvature, from the inner wall surface of the intake duct. The air flow is disturbed by the separation of the intake air.

Patent Document 1 describes a technique for suppressing air flow noise by suppressing separation by performing dimple processing on a wall surface of a bent portion having a small radius of curvature of an intake duct.
JP-A-2001-280311

  However, Patent Document 1 does not describe any method for preventing the intake sound from becoming muddy.

  In order to prevent the intake sound from becoming muddy, it is necessary to reduce the 0.5th order component. For this purpose, each intake air is adjusted by adjusting the intake manifold branch length and the throttle chamber position. It is known that it is effective to make the path length to the engine side end of the port equal.

  However, it is difficult to make it the same length due to the balance with characteristics such as engine output and the layout restrictions in the engine room, and even if it can be made the same length, The contribution of the composite sound with the sound reflected by the sound increases, and the sound may become muddy.

  In other words, in order to prevent the intake sound from becoming muddy, it is important to suppress the composite of the reflected sound in the intake passage and make it acoustically equal in length.

  Therefore, an object of the present invention is to prevent the intake sound from becoming a muddy sound by making the path length of the intake passage acoustically the same length.

  An intake device for an engine according to the present invention has an intake inlet into which intake air is introduced, and a volume portion to which a plurality of branch portions respectively communicating with an intake port of the engine are connected, and at least the inner wall surface of the volume portion A sound adjusting portion subjected to dimple processing is provided in a portion facing the branch opening.

  According to the present invention, the sound pressure level of the intake sound is reduced by providing each of the acoustic adjustment portions that are dimpled on at least a portion of the inner wall surface of the volume portion facing the branch opening, and the 0.5th order component Therefore, it is possible to prevent the intake sound from becoming cloudy without making the path length from the intake inlet (collector tank inlet) to the engine side end of the branch of each cylinder the same.

  In addition, the turbidity of the intake sound can be prevented without making the path length from the intake inlet (collector tank inlet) to the engine side end of the branch of each cylinder equal to the physical length. The degree increases.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of an intake manifold for an in-line four-cylinder engine to which the present embodiment is applied.

  1 is a collector tank as a volume part, 2 to 5 are branches connected to the intake ports of the respective cylinders, and 6 to 9 are acoustic adjustment parts in which the inner wall surface of the collector tank 1 is dimpled as will be described later. This is a dimple processing portion.

  The branches 2 to 5 are connected to the intake ports of the first to fourth cylinders, respectively.

  The collector tank 1 has a collector tank inlet 10 as an intake inlet opening at one end in the longitudinal direction, and a throttle chamber (not shown) is connected to the collector tank inlet 10.

  In addition, on the side wall of the collector tank 1, communication holes 11 to 14 as branch openings communicating with the branches 2 to 5 are arranged in the longitudinal direction of the collector tank 1.

  With the above configuration, intake air introduced from an air duct (not shown) is introduced into the collector tank 1 with the intake air amount adjusted in the throttle chamber, and supplied to each cylinder of the engine via each branch 2-5.

  It should be noted that the lengths of the branches 2 to 5 are different depending on the layout constraints in the engine room and the requirements from the engine output characteristics, and the lengths from the collector tank inlet 10 to the communication holes 11 to 14 are also different. Therefore, the distance from the collector tank inlet 10 to the engine side end of the branch of each cylinder (hereinafter referred to as the port length) differs for each cylinder.

  Next, the dimple processing portions 6 to 9 will be described.

  The dimple processing portions 6 to 9 are provided at portions where sound waves transmitted through the communication holes 11 to 14 collide with the collector tank 1, that is, at positions facing at least the communication holes 11 to 14.

  The number of dimples differs depending on the distance from the collector tank inlet 10, and the number of dimples increases as the distance from the collector tank inlet 10 increases. In addition, a product obtained by multiplying the volume of one dimple by the number of dimples provided in each of the dimple processing portions 6 to 9 is an integrated dimple volume (hereinafter referred to as dimple volume) and a ratio of dimple volumes between the cylinders (for example, dimple processing). Dimple volume attenuation ratio (hereinafter referred to as attenuation ratio) where A is the dimple volume of the portion 6 and A is the dimple volume of the dimple processing portion 7, and the sum of the dimple volumes of all the dimple processing portions 6 to 9 Is called the total volume of dimples.

  The effect of the dimple processing as described above will be described with reference to FIGS.

  2 shows the intake mode of each branch 2 to 5 with the sound pressure level on the vertical axis and the frequency on the horizontal axis, respectively, when the dimple processing is not performed, and FIG. 3 is the case where the dimple processing is performed. is there. In addition, A to D in the figure are the intake modes of the branches 2 to 5, respectively (the same applies to FIG. 3 and FIG. 7 described later).

  As shown in FIGS. 2 and 3, each of the branches 2 to 5 has a different intake mode and takes a peak value in different frequency bands. This is because the port length of each cylinder is different as described above.

  Due to this shift in the intake mode, a 0.5th order component is generated and becomes larger by combining several 0.5th order components. It is known that the development of the 0.5th order component is the cause of the intake sound becoming muddy.

  2 and 3 both show peaks in different frequency bands, but the sound pressure level in FIG. 3 is smaller. In the present embodiment, this is because the pressure wave transmitted from each branch 2 to 5 to the collector tank 1 hits the dimple processing portions 6 to 9 provided on the wall surface facing the communication holes 11 to 14 of the collector tank 1. It is because is reduced.

  When the intake mode is reduced, the development of the 0.5th order component is also suppressed, so that it is possible to prevent the intake sound from becoming muddy.

  In other words, if the intake mode is reduced by providing the dimple processing portions 6 to 9 and the 0.5th-order component is reduced, the length of the branches 2 to 5 is not made physically equal, but acoustically The effect equivalent to physically making the branch portions 2 to 5 equal in length is obtained, and the turbidity of the intake sound can be prevented. In addition, the state equivalent to making the branch parts 2-5 physically equal length is called acoustic equal length.

  Next, the relationship between the dimple shape, the dimple volume, the attenuation ratio, the processing range, and the acoustic isometric length of the dimple processing portions 6 to 9 will be described.

(About dimple shape)
Examples of the dimple shape are shown in FIGS. 9 shows a triangular pyramid, FIG. 10 shows a quadrangular pyramid, FIG. 11 shows a cone, and FIG. 12 shows a hemisphere.

  The relationship between the dimples shaped as shown in FIGS. 9 to 12 and the acoustic isometric length is as shown in FIG. FIG. 4 shows the results of investigating the influence of the dimple shape on the isometricity, with the vertical axis representing the equal length and the horizontal axis representing the dimple shape. It is assumed that the dimple density (the number of dimples per unit area of the inner wall surface of the collector tank 1) is constant, and the vertical axis becomes higher (approaching the same length) as it goes down.

  As is apparent from FIG. 4, it is understood that if the dimple density is the same, the isometricity increases in the order of triangular pyramid, quadrangular pyramid, cone, and hemisphere.

  Therefore, the shape of the dimple can be selected according to the physical isometric length to increase the acoustic isometric length.

  Even when the density and processing range of the dimple processing are limited due to the size and shape of the collector tank 1 and problems in the processing process, the acoustic isometric length can be adjusted by the shape of the dimple.

(About dimple volume and damping ratio)
FIG. 5 shows the influence of the dimple volume and damping ratio on the isometricity, with the vertical axis representing the equal length and the horizontal axis representing the dimple volume. Note that the dimple processed portions 6 and 7, 7 and 8, and 8 and 9 all have the same damping ratio. That is, the dimple volume increases in the order of the dimple processing portions 9, 8, 7, 6.

  As can be seen from FIG. 5, the greater the dimple volume and the greater the damping ratio, the higher the isometricity.

  Therefore, by adjusting the dimple volume and the damping ratio according to the physical isometric length, the acoustic isometric height can be increased. For example, when the interval between the communication holes 11 to 14 is wide and the physical isometric length is low, both the dimple volume and the damping ratio may be increased.

(About processing range)
FIG. 6 is a diagram showing the relationship between the processing range of the dimple processing portions 6 to 9 and the equal length, where the vertical axis is the equal length and the horizontal axis is the range where the dimple processing is performed.

  The range in which dimple processing is performed will be described with reference to FIG. FIG. 8 is a cross-sectional view of the collector tank 1, and the wall surface on the side facing the communication hole 1 with respect to the diameter substantially perpendicular to the direction in which the communication hole 1 opens from the center of the collector tank 1 is an L side wall surface. The wall surface on the communication hole 1 side is an R side wall surface.

  As shown in FIG. 6, the equal length increases in the order of only the R side wall surface, only the L side wall surface, and both the L side wall surface and the R side wall surface.

  Therefore, the acoustic isometric length can be increased by adjusting the range where the dimple processing is performed according to the physical equal length. For example, when there is a large difference in port length between the cylinders, and it is not possible to make the acoustic length equal by simply increasing the dimple density, the range for performing dimple processing may be widened.

  Next, a case where the collector tank inlet 10 opens to a place other than the end of the collector tank 1, for example, a case where the collector tank inlet 10 opens between the branches 12 and 13 as shown in FIG. 13 will be described with reference to FIG.

  In FIG. 7, the vertical axis represents the damping ratio, and the horizontal axis represents the positions of the communication holes 11 to 14, and represents the setting of the damping ratio for increasing the isometric length.

  When the collector tank inlet 10 is close to the communication hole 11, the damping ratio is set to increase as the distance from the communication holes 12, 13, 14 and the communication hole 11 increases.

  When the collector tank inlet 10 is close to the communication hole 12, the damping ratio is increased as the distance from the communication holes 13 and 14 and the communication hole 12 increases, and the distance from the communication hole 12 is approximately equal. Is set to approximately the same attenuation ratio.

  When the collector tank inlet 10 is close to the communication hole 13, the damping ratio increases as the distance from the communication holes 12 and 11 and the communication hole 13 increases, and the communication hole 14 and the communication hole 12 having substantially the same distance from the communication hole 13 are substantially the same. Set to the same damping ratio.

  When the collector tank inlet 10 is close to the communication hole 14, the damping ratio is set to increase as the distance from the communication holes 13, 12, 11 and the communication hole 14 increases.

  As described above, in the present embodiment, the branch portions 2 to 5 pass through the communication holes 11 to 14 on the inner wall surface of the collector tank 1 including the intake air inlet 10 and the plurality of communication holes 11 to 14 arranged substantially linearly. Since the dimple processing portions 6 to 9 are subjected to dimple processing at the respective portions where the sound waves transmitted from the collector to the collector 1 collide with each other, the sound pressure level of the intake sound is reduced, and the 0.5 order component The development of can be suppressed.

  As a result, the path length from the collector tank inlet 10 to the engine side ends of the branches 2 to 5 can be made equal acoustically without being physically equal, and the turbidity of the intake sound can be achieved. Can be prevented. Further, since the length can be made acoustically equal without physically equal length, the degree of freedom in designing the intake manifold 1 is increased. For example, other characteristics such as output and constraints on the layout of the engine room While being satisfied, it is possible to prevent the turbidity of the intake sound.

  Depending on the path length difference from the openings 11 to 14 to the engine side ends of the branches 2 to 5, for example, if the port length difference between the cylinders is large, the dimple volume is set large. By doing so, the acoustic isometric can be increased.

  Depending on the difference in the path length from the opening to the engine side end of each branch, for example, if the port length difference between cylinders is large, the damping ratio is set to a large value. It is possible to increase the isometric length.

  By adjusting the dimple volume by changing the dimple shape without changing the dimple density, for example, there are restrictions on the size and shape of the collector tank 1 and the processing steps, and the dimple density cannot be increased. However, it is possible to increase the acoustical length.

  By setting the distribution of the dimple density in the circumferential direction of the dimple processing portions 6 to 9 according to the difference in the port length, there is a large difference in the port length between the cylinders, and simply increasing the dimple density Even when the length cannot be made acoustically, the acoustic length can be increased.

  In this embodiment, the case where the present invention is applied to a four-cylinder engine has been described. However, in the case of a 3, 5, 6, 8, 10, 12-cylinder engine, etc. In the case of an engine or the like, the same can be applied to each bank.

  It can also be applied to an exhaust manifold to prevent turbidity of exhaust sound.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

  The present invention can be applied to prevent the turbidity of the intake and exhaust sounds of a multi-cylinder engine.

It is the schematic of the structure of this embodiment. It is a figure showing the intake mode at the time of using the conventional collector tank. It is a figure showing the intake mode at the time of using the collector tank of this embodiment. It is a figure showing the influence on the iso-length of a dimple shape. It is a figure showing the influence to the dimple total volume and damping ratio by equal length. It is a figure showing the influence on the equal length of a dimple processing range. It is a figure showing the attenuation ratio according to the position of an opening part. It is sectional drawing of a collector tank. It is a figure showing the case where a dimple shape is a triangular pyramid. It is a figure showing the case where a dimple shape is a quadrangular pyramid. It is a figure showing the case where a dimple shape is a cone. It is a figure showing the case where a dimple shape is a hemisphere. It is a figure showing the case where a collector tank inlet opens between the branches 12 and 13.

Explanation of symbols

1 Collector tank 2-5 Branch 6-9 Dimple processing part 10 Collector tank inlet 11-14 Communication hole

Claims (5)

An intake port through which intake air is introduced, each having a volume part to which a plurality of branch parts communicating with the intake port of the engine are connected;
An intake device for an engine, wherein a dimple-processed acoustic adjustment portion is provided at least on a portion of the inner wall surface of the volume portion facing the branch opening.   An integrated dimple volume amount calculated by multiplying the volume per dimple of the acoustic adjustment unit by the number of dimples is set in accordance with a difference in path length from the intake inlet to the engine side end of each branch. Item 2. The engine intake device according to Item 1.   A dimple volume attenuation ratio, which is a ratio of integrated dimple volume amounts between one acoustic adjustment unit and another acoustic adjustment unit, is set according to a difference in path length from the intake inlet to the engine side end of each branch. The engine intake device according to claim 1 or 2.   The engine intake device according to claim 2 or 3, wherein the integrated dimple volume is adjusted by changing a dimple shape without changing a dimple density which is the number of dimples per unit area of the volume portion.   The distribution of the dimple density in the circumferential direction from the portion where the sound wave transmitted through the opening into the volume collides is determined according to the difference in the path length from the intake inlet to the end of the engine on each branch. The engine intake device according to any one of claims 1 to 4, which is set.

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