JP2014234810A - Intake sound generating device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake sound generating device capable of increasing sound pressure of a desired frequency band.SOLUTION: An intake sound generating device 11 has an introduction conduit 12 with one end connected to an intake passage 4 and the other end opened to the outside, and an oscillation body 13 closing the introduction conduit 12 in the middle of the introduction conduit 12. The oscillation body 13 is oscillated using intake pulsations as an excitation source to generate intake sound, and the intake sound is transmitted to a vehicle interior. The introduction conduit 12 has a first conduit 15 which is situated on one end side of the oscillation body 13 and is connected to the intake passage 4, and a second conduit 16 which is situated on the other end side of the oscillation body 13 and increases the sound pressure of intake sound of a predetermined frequency band in the intake sound generated by oscillation of the oscillation body 13. The second conduit 16 is formed with an expansion part 20 in which the passage sectional area is expanded relatively.

Description

  The present invention relates to an intake sound generation device for an internal combustion engine that generates intake sound using intake air pulsation of the internal combustion engine.

  2. Description of the Related Art Conventionally, an intake sound generation device that increases the sound pressure at a predetermined frequency of intake sound using intake pulsation of an internal combustion engine is known.

  For example, Patent Document 1 discloses an introduction pipe that guides intake pulsation in an intake system, a vibrating body that is provided so as to cover one end of the introduction pipe, and is connected to the introduction pipe via the vibrating body. An intake sound generator having a resonance tube that increases the sound pressure of intake sound in a predetermined frequency band among intake sound generated by vibration of a vibrating body is disclosed.

JP 2009-22201 A

  However, in such a conventional intake sound generation device, the pipe length of the resonance tube is adjusted according to the frequency band to which the sound pressure is added. If it cannot be set for a long time, it may not be possible to sufficiently increase the intake sound pressure of the desired frequency.

  Accordingly, the present invention provides an introduction pipe line having one end connected to the intake passage of the internal combustion engine and the other end opened to the outside, and a vibrating body arranged in the middle of the introduction pipe to block the introduction pipe. The introduction pipe line is located on one end side with respect to the vibrating body, and is located on the other end side with respect to the first pipe line into which the intake air pulsation in the intake passage is introduced. In the intake sound generation device for an internal combustion engine having a second pipe that increases the sound pressure of the intake sound in a predetermined frequency band among the intake sound generated by the vibration of the vibrating body, a passage cross-sectional area is provided in the introduction pipe. By forming a relatively enlarged expansion part, the sound pressure obtained by changing the frequency band of the intake sound to a relatively low frequency side in the pipe line on the side where the expansion part is provided in the introduction pipe line is obtained. It is characterized by adding.

  When the extension portion is provided in the first pipe line, the first pipe line can generate a different resonance frequency for each part before and after the extension part. Moreover, when the said expansion part is provided in the said 2nd pipe line, it becomes possible for the said 2nd pipe line to generate a different resonant frequency for every part before and behind the said expansion part.

  A plurality of the extension portions may be provided in at least one of the first pipeline and the second pipeline. If a plurality of the extension portions are provided in at least one of the first pipeline and the second pipeline, a plurality of relatively short pipelines are formed before and after the extension portion. These short pipelines Since the resonance frequency is set every time, a plurality of resonance frequencies can be set.

  Moreover, you may make it provide the said expansion part only in the said 2nd pipe line. Thereby, even if it is the limited space in an engine room, it becomes possible to set the said expansion part comparatively freely.

  According to the present invention, by providing the extension portion, it is possible to move the frequency band to which the sound pressure is added to the low frequency side without changing the lengths of the first and second pipes.

  If a plurality of the extension portions are provided in at least one of the first pipe line and the second pipe line, it is possible to increase the sound pressure in a desired frequency range by superimposing a plurality of resonance frequencies. It becomes.

  Further, by providing the extension part only in the second pipe line, the setting position of the extension room in the engine room can be set relatively freely.

Explanatory drawing which showed the inside of the engine room of a vehicle typically. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the intake sound generator of the internal combustion engine which concerns on 1st Example of this invention. Explanatory drawing which showed an example of the frequency band of the intake sound to which sound pressure is added by air column resonance. Explanatory drawing which showed the state on which the frequency bands to which sound pressure is added were overlapped. Explanatory drawing which showed typically the intake sound generator of the internal combustion engine which concerns on 2nd Example of this invention. Explanatory drawing which showed typically the intake sound generator of the internal combustion engine which concerns on 3rd Example of this invention. Explanatory drawing which showed typically the intake sound generator of the internal combustion engine which concerns on 4th Example of this invention. Explanatory drawing which showed typically the intake sound generator of the internal combustion engine which concerns on 5th Example of this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing the inside of an engine room 1 of a vehicle to which an intake sound generation device for an internal combustion engine according to the present invention is applied.
In the engine room 1, for example, a 6-cylinder engine 2 is arranged as an internal combustion engine. Air (intake air) taken from outside is supplied to each cylinder of the engine 2 via the intake system 3.

  The intake system 3 is generally composed of an upstream intake passage 4 and a downstream intake manifold 5.

  The intake passage 4 is arranged so that an intake intake 6 is opened in front of the vehicle, and an air cleaner 7, an air flow meter 8, and a throttle valve 9 are arranged in this order from the upstream side.

  The intake manifold 5 has a plurality of branch pipes 5 a having the same number as the number of cylinders, and these branch pipes 5 a communicate with each cylinder of the engine 2.

  The intake passage 4 is provided with an intake sound generation device 11 that generates intake sound using intake pulsation generated in the intake system 3. The intake sound generator 11 is located between the air cleaner 7 and the throttle valve 9 and has an introduction pipe line 12 having one end connected to the intake passage 4 and the other end opened to the outside, And an oscillating body 13 that is disposed in the middle of the pipe line 12 and closes the introduction pipe line 12. The oscillating body 13 is vibrated using the intake pulsation as an excitation source to generate an intake sound, and the intake sound is Communicate indoors. In the present embodiment, the other end opening of the introduction pipe line 12 is located in the engine room 1 and faces the dash panel 14.

  FIG. 2 is an explanatory view schematically showing a schematic configuration of the intake sound generation device 11 of the first embodiment.

  The introduction pipe line 12 made of a resin material is positioned on one end side (left side in FIG. 2) from the vibrating body 13 and connected to the intake passage 4, and the other end side from the vibrating body 13 ( And a second pipe line 16 that is located on the right side in FIG. 2 and increases the sound pressure of the intake sound in a predetermined frequency band among the intake sounds generated by the vibration of the vibrating body 13. A predetermined portion of the introduction pipe 12 is fixed to the vehicle body in the engine room 1.

  The first duct 15 has a cylindrical general portion 17 and a flange-shaped flange portion 18 formed at the other end of the general portion 17. One end of the general portion 17 communicates with the intake passage 4 at a position between the air cleaner 7 and the throttle valve 9. The flange portion 18 is connected to one end of the second pipe line 16. In the present embodiment, the first pipe line 15 is formed integrally with the intake passage 4, but both may be connected as separate parts later.

  The vibrating body 13 is made of a predetermined resin material (for example, a polyester-based thermoplastic elastomer) having rubber characteristics and higher member strength than rubber. The vibrating body 13 has a bottomed cylindrical shape, and has a bottom wall portion 13a having a predetermined thickness, a bellows-like cylindrical portion 13b, and a flange-like flange portion 13c formed at the opening edge of the cylindrical portion 13b. doing. The bottom wall portion 13a is disposed so as to be orthogonal to the central axis of the first pipeline 15, and vibrates using the intake pulsation as an excitation source. The cylindrical portion 13b is formed thinner than the bottom wall portion 13a in order to promote vibration of the bottom wall portion 13a. The flange portion 13 c is fixed to the flange portion 18 of the first pipeline 15 so as to surround the periphery of the other end opening of the first pipeline 15.

  The second pipe line 16 includes a cylindrical general portion 19, a cylindrical expansion portion 20 whose passage cross-sectional area is relatively enlarged with respect to the general portion 19, and a vibrating body housing portion in which the vibrating body 13 is housed. 21.

  In this first embodiment, one extended portion 20 is formed in the general portion 19 of the second pipe line 16, and the general portion 19a connected to one end of the extended portion 20 is on one end side (the left side in FIG. 2). The general body 19b connected to the other end of the extended portion 20 has an opening on the other end side (the right end in FIG. 2) facing the dash panel 14 in the engine room 1. . The vibrating body accommodating portion 21 is accommodated concentrically with the vibrating body 13 not contacting the inner peripheral surface thereof, and a flange 21a is formed at the opening end thereof. Then, the flange 13a is sandwiched between the flange 21a and the flange 17 of the first pipe 15, and the vibrator 13 is welded to each other, for example, so that the vibrator 13 is connected to the first pipe 15 and the second pipe. It is held and fixed with the path 16. That is, the second pipe line 16 is configured not to communicate with the intake passage 4.

  In the first embodiment as described above, by forming the expansion portion 20 in the second pipe line 16, as shown in FIG. 3, the intake sound to which sound pressure is added by the air column resonance of the second pipe line 16. The frequency band (the frequency at which the peak of the sound pressure level appears) is changed to the relatively low frequency side. A characteristic line indicated by a broken line in FIG. 3 is an example of a frequency characteristic of the intake sound when the extended portion 20 is not provided, and a characteristic line indicated by a solid line in FIG. 3 indicates a frequency when the extended portion 20 is provided. It is an example of a characteristic.

  The second pipe line 16 can increase the sound pressure of the intake sound in a desired frequency band by adjusting the axial length of the second pipe line 16, etc., but in the first embodiment described above, By providing the extended portion 20 in the second pipeline 16, it becomes possible to set the resonance frequency for each of the general portions 19a and 19b before and after the extended portion 20, and the axial length of the second pipeline 16 is changed. Without this, it is possible to change the frequency band of the intake sound to which the sound pressure is added by the air column resonance of the second pipe line 16.

  In other words, the second pipe line 16 in the first embodiment includes the position of one end connected to the first pipe line 15, the position of the other end facing the dash panel 14, and the position of the one end to the position of the other end. By adjusting the axial length and inner diameter of the general part 19 and the position, length and inner diameter of the expansion part 20 without changing the route in the engine room 1, the sound of the intake sound in the desired frequency band is adjusted. It is possible to increase the pressure. That is, in the first embodiment, the desired length of the introduction pipe 12 can be changed without changing the axial length of the introduction pipe 12, that is, without changing the length of the first pipe 15 and the second pipe 16 in the axial direction. It is possible to increase the sound pressure of the intake sound in the frequency band. Therefore, when the intake sound generation device 11 is arranged in the engine room 1, interference with peripheral components can be easily avoided without changing the existing component layout.

  Then, the frequency band to which the sound pressure moved to the low frequency side by adding the expansion unit 20 is added is the frequency band to which the sound pressure is added by the resonance of the vibrating body 13 or the air column resonance of the first pipe line 15. Thus, it is possible to increase the sound pressure in the overlapped frequency band by overlapping with the frequency band to which the sound pressure is added. For example, as shown in FIG. 4, the expansion portion 20 is provided in the second pipe line 16, and the frequency band to which sound pressure is added by the air column resonance of the second pipe line 16 is moved to the low frequency side, and the first pipe If the frequency band where the sound pressure is added by the air column resonance of the path 15 is overlapped, the sound pressure of the intake sound in the frequency band where the sound pressure is added by the air column resonance of the first duct 15 is increased. It becomes possible.

  A characteristic line indicated by a broken line in FIG. 4 shows an example of the frequency characteristic of the intake sound when the expansion portion 20 is not provided in the second pipeline 16, and the frequency at which the peak of the sound pressure level appears is from the low frequency side. In order, the resonance frequency is due to the resonance frequency of the vibrating body 13, due to the air column resonance of the first duct 15, and due to the air column resonance of the second duct 16.

  A characteristic line indicated by a solid line in FIG. 4 shows an example of the frequency characteristic of the intake sound when the expansion portion 20 is provided in the second pipeline 16, and the sound pressure is added by the air column resonance of the second pipeline 16. Is overlapped with the frequency band to which the sound pressure is applied by the air column resonance of the first duct 15, and the sound pressure in the overlapped frequency band is increased.

  Note that the amount of movement of the frequency band of the intake sound to which the sound pressure is added by air column resonance to the low frequency side depends on the position of the expansion portion 20 in the second pipe line 16, the axial length of the expansion portion 20, the inner diameter, and the like. It can be adjusted. Further, the larger the axial length and the inner diameter of the extended portion 20, the greater the amount of movement of the frequency band to which the sound pressure is applied by air column resonance toward the low frequency side.

  Hereinafter, other embodiments of the present invention will be described, but the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted.

  A second embodiment of the present invention will be described with reference to FIG. The intake sound generation device 24 of the second embodiment has substantially the same configuration as the intake sound generation device 11 of the first embodiment described above, but the expansion portion 20 is formed only in the first pipeline 15.

  That is, the first pipe line 15 in the second embodiment includes a cylindrical general part 17, a cylindrical extended part 20 whose passage cross-sectional area is relatively enlarged with respect to the general part 17, and a second pipe line. 16 and a flange portion 18 connected to one end of 16. The general portion 17 a connected to one end (the left end in FIG. 5) of the expansion portion 20 is connected to the intake passage 4 at one end side. The general portion 17b connected to the other end (the right end in FIG. 5) of the extended portion 20 has a flange portion 18 formed on the other end side.

  The second pipe line 16 in the second embodiment has a cylindrical general portion 19 and a vibrating body accommodating portion 21 in which the vibrating body 13 is accommodated, and the vibrating body accommodating portion 21 on one end side of the general portion 19. Are connected, and the other end side of the general portion 19 is opened in the engine room 1 so as to face the dash panel 14.

  In such a second embodiment, by forming the expansion portion 20 in the first conduit 15, the frequency band of the intake sound to which sound pressure is added by the air column resonance of the first conduit 15 is relatively It is changed to the low frequency side.

  More specifically, in this second embodiment, by providing the expansion portion 20 in the first pipeline 15, it becomes possible to set the resonance frequency for each of the general portions 17a and 17b before and after the expansion portion 20. Without changing the axial length of the first pipe line 15, it is possible to change the frequency band of the intake sound to which sound pressure is added by the air column resonance of the first pipe line 15.

  That is, the first pipe line 15 in the second embodiment has a position of one end connected to the intake passage 4, a position connected to the second pipe line 16, and the position of the one end to the position of the other end. Without changing the route in the engine room 1, the sound pressure of the intake sound in the desired frequency band can be adjusted by adjusting the axial length and inner diameter of the general portion 17 and the position, length and inner diameter of the expansion portion 20. It can be increased. Therefore, also in the intake sound generation device 24 of the second embodiment, the axial length of the introduction pipe 12 is not changed, that is, the axial lengths of the first pipe 15 and the second pipe 16 are changed. Thus, the sound pressure of the intake sound in a desired frequency band can be increased.

  For this reason, the intake sound generator 24 can increase the sound pressure of the intake sound in a desired frequency band without changing the axial length of the introduction pipe line 12. Therefore, it is possible to easily avoid interference with peripheral components without changing the existing component layout.

  The frequency band to which the sound pressure moved to the low frequency side by adding the expansion unit 20 is added is the frequency band to which the sound pressure is added by the resonance of the vibrating body 13 or the air column resonance of the second pipe line 16. Thus, it is possible to increase the sound pressure in the overlapped frequency band by overlapping with the frequency band to which the sound pressure is added.

  In the second embodiment, the amount of movement of the frequency band of the intake sound to which the sound pressure is added by the air column resonance to the low frequency side is determined by the position of the expansion portion 20 in the first pipe line 15 and the expansion portion 20. It can be adjusted by the axial length, inner diameter, and the like. Further, the larger the axial length and the inner diameter of the extended portion 20, the greater the amount of movement of the frequency band to which the sound pressure is applied by air column resonance toward the low frequency side.

  FIG. 6 shows a third embodiment of the present invention. The intake sound generation device 34 of the third embodiment has substantially the same configuration as the intake sound generation device 11 of the first embodiment described above, but both the second pipe line 16 and the first pipe line 15 are respectively provided. An extended portion 20 is formed.

  That is, the first pipe line 15 in the third embodiment includes a cylindrical general part 17, a cylindrical extended part 20 a whose passage sectional area is relatively enlarged with respect to the general part 17, and a second pipe line. 16 and a flange portion 18 connected to one end of 16. The general portion 17a connected to one end (the left end in FIG. 6) of the extended portion 20a is connected to the intake passage 4 at one end side. The general portion 17b connected to the other end (the right end in FIG. 6) of the extended portion 20a has a flange portion 18 formed on the other end side. The second pipe line 16 in the third embodiment accommodates a cylindrical general portion 19, a cylindrical expansion portion 20 b whose passage cross-sectional area is relatively enlarged with respect to the general portion 19, and the vibrating body 13. And a vibrating body accommodating portion 21. The general part 19a is connected to one end (the left end in FIG. 6) of the extended part 20b, and the general part 19b is connected to the other end (the right end in FIG. 6) of the extended part 20b.

  In the third embodiment, the frequency band of the intake sound to which sound pressure is added by the air column resonance of the first conduit 15 by forming the expansion portion 20a in the first conduit 15 is relatively low. The frequency band of the intake sound to which the sound pressure is added by the air column resonance of the second pipeline 16 by forming the expansion portion 20b in the second pipeline 16 while being changed to the frequency side is relatively low frequency Changed to

  Specifically, in the third embodiment, the first pipe 15 and the second pipe 16 are provided with the expansion portions 20a and 20b, respectively, so that the axial length of the first pipe 15 is not changed. The frequency band of the intake sound to which sound pressure is applied by the air column resonance of the first pipe line 15 can be changed, and the second pipe line 16 can be changed without changing the axial length of the second pipe line 16. It is possible to change the frequency band of the intake sound to which the sound pressure is added by the air column resonance.

  That is, the first pipe line 15 in the third embodiment has a position of one end connected to the intake passage 4, a position connected to the second pipe line 16, and a position from the one end position to the other end position. Without changing the route in the engine room 1, the sound pressure of the intake sound in a desired frequency band can be adjusted by adjusting the axial length and inner diameter of the general portion 17 and the position, length and inner diameter of the expansion portion 20a. It can be increased. Further, the second pipe line 16 has a position of one end connected to the first pipe line 15, a position of the other end facing the dash panel 14, and a position in the engine room 1 from the position of the one end to the position of the other end. It is possible to increase the sound pressure of the intake sound in a desired frequency band by adjusting the axial length and inner diameter of the general portion 19 and the position, length and inner diameter of the expansion portion 20b without changing the path. It is possible. Accordingly, also in the intake sound generation device 34 of the third embodiment, the axial length of the introduction pipe 12 is not changed, that is, the axial lengths of the first pipe 15 and the second pipe 16 are changed. Thus, the sound pressure of the intake sound in a desired frequency band can be increased.

  Therefore, the intake sound generation device 34 can increase the sound pressure of the intake sound in a desired frequency band without changing the axial length of the introduction pipe line 12. Therefore, it is possible to easily avoid interference with peripheral components without changing the existing component layout.

  In the third embodiment, the frequency band to which sound pressure is applied by air column resonance and the frequency band to which sound pressure is added by resonance of the vibrating body 13 are overlapped and overlapped with each other. The sound pressure in the frequency band can be increased.

  FIG. 7 shows a fourth embodiment of the present invention. The intake sound generation device 44 of the fourth embodiment has substantially the same configuration as the intake sound generation device 11 of the first embodiment described above, but a plurality of expansion portions 20 are formed in the second pipeline 16. Yes.

  That is, the second pipe line 16 of the fourth embodiment includes a cylindrical general portion 19 and two cylindrical expansion portions 20a and 20b whose passage sectional area is relatively enlarged with respect to the general portion 19. And a vibrating body accommodating portion 21 in which the vibrating body 13 is accommodated.

  More specifically, in the second pipe line 16 of the fourth embodiment, the general portion 19a is connected to one end (the left end in FIG. 7) of the expansion portion 20a, and the expansion portion 20a and the expansion portion 20b are connected by the general portion 19b. The general portion 19c is connected to the other end (the right end in FIG. 7) of the extended portion 20b. The general portion 19c is opened such that the other end side (the right end in FIG. 7) faces the dash panel 14 in the engine room 1, for example.

  Further, the second pipe line 16 in the fourth embodiment has a position of one end connected to the first pipe line 15, a position of the other end facing the dash panel 14, and a position of the other end from the position of the one end. By adjusting the axial length and inner diameter of the general part 19 and the position, length and inner diameter of the expansion part 20 without changing the route in the engine room 1 until the sound of the intake sound in the desired frequency band It is possible to increase the pressure. Therefore, the intake sound generation device 44 can be used without changing the axial length of the introduction pipe 12, that is, without changing the axial lengths of the first pipe 15 and the second pipe 16. It is possible to increase the sound pressure of the intake sound in the frequency band.

  In the fourth embodiment, the same effects as those of the first embodiment described above can be obtained, and the general portions 19a, 19b, 19c in the second pipeline 16 are relatively short pipelines. Since a plurality of resonance frequencies are set for each of these short pipelines, it is possible to increase the sound pressure in a desired frequency range by superimposing these plurality of resonance frequencies. That is, by setting a plurality of expansion units 20, it is possible to easily set a frequency region that increases sound pressure.

  FIG. 8 shows a fifth embodiment of the present invention. The intake sound generation device 54 of the fifth embodiment has substantially the same configuration as the intake sound generation device 24 of the second embodiment described above, but a plurality of expansion portions 20 are formed in the first pipeline 15. Yes.

  That is, the first pipe line 15 of the fifth embodiment includes a cylindrical general portion 17 and two cylindrical expanded portions 20a and 20b whose passage cross-sectional area is relatively enlarged with respect to the general portion 17. And a flange portion 18 connected to the other end of the first pipe line 15.

  More specifically, in the first pipe line 15 in the fifth embodiment, the general portion 17a is connected to one end of the expansion portion 20a (the left end in FIG. 7), and the expansion portion 20a and the expansion portion 20b are connected by the general portion 17b. The general portion 17c is connected to the other end (the right end in FIG. 7) of the extended portion 20b. One end of the general portion 17a (the left end in FIG. 8) is connected to the intake passage 4, and the general portion 17c has a flange portion 18 formed at the other end (the right end in FIG. 8).

  Further, the first pipe line 15 in the fifth embodiment has a position of one end connected to the intake passage 4, a position connected to the second pipe line 16, and a position from the one end position to the other end position. By changing the axial length and inner diameter of the general portion 17 and the positions, lengths and inner diameters of the expansion portions 20a and 20b without changing the route in the engine room 1, the sound of the intake sound in a desired frequency band is adjusted. It is possible to increase the pressure. Therefore, also in the intake sound generating device 54 of the fifth embodiment, the axial length of the introduction pipe 12 is not changed, that is, the axial lengths of the first pipe 15 and the second pipe 16 are changed. Thus, the sound pressure of the intake sound in a desired frequency band can be increased.

  In the fifth embodiment, the same effects as those of the second embodiment described above can be obtained, and the general portions 17a, 17b, and 17c in the first conduit 15 are relatively short conduits. Since a plurality of resonance frequencies are set for each of these short pipelines, it is possible to increase the sound pressure in a desired frequency range by superimposing these plurality of resonance frequencies. That is, by setting a plurality of expansion units 20, it is possible to easily set a frequency region that increases sound pressure.

  In each of the above-described embodiments, the other end of the second pipe line 16 is opened so as to face the dash panel 14 in the engine room 1, but the other end of the second pipe line 16 extends to the vehicle interior. The other end of the second pipe line 16 may be opened in the passenger compartment.

  Further, in the configuration in which the expansion portion 20 is provided only in the second pipe line 16 as in the first and fourth embodiments described above, the position, length, and inner diameter of the expansion portion 20 are set relatively freely. be able to.

  And the number of the expansion parts 20 provided in the 1st pipe line 15 and the 2nd pipe line 16 is not limited to one or two, It is also possible to provide two or more.

DESCRIPTION OF SYMBOLS 11 ... Inhalation sound generator 12 ... Introducing pipe line 13 ... Vibrating body 15 ... 1st pipe line 16 ... 2nd pipe line 17 ... General part 18 ... Flange part 19 ... General part 20 ... Expansion part 21 ... Vibrating body accommodating part

Claims (3)

An introduction pipe line having one end connected to the intake passage of the internal combustion engine and the other end opened to the outside; A pipe line is positioned on one end side of the vibrating body and is introduced with intake pulsation in the intake passage, and is positioned on the other end side of the vibrating body by vibration of the vibrating body. In the intake sound generator for an internal combustion engine having a second pipe that increases the sound pressure of the intake sound in a predetermined frequency band among the generated intake sounds,
By forming an expanded portion having a relatively enlarged passage cross-sectional area in the introduction pipe line, relative to the frequency band of the intake sound in the pipe line on the side where the expansion section is provided in the introduction pipe line An intake sound generation device for an internal combustion engine, characterized by adding a sound pressure changed to a low frequency side to the internal combustion engine.   2. The intake sound generation device for an internal combustion engine according to claim 1, wherein a plurality of the extension portions are provided in at least one of the first pipeline and the second pipeline.   The intake sound generating device for an internal combustion engine according to claim 1 or 2, wherein the extension portion is provided only in the second pipe line.

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