JP7191466B2 - internal combustion engine silencer - Google Patents

Description

The present invention relates to a muffler for an internal combustion engine, and more particularly to a muffler applied to an internal combustion engine that supercharges intake air with a supercharger.

2. Description of the Related Art Conventionally, a vehicle such as an automobile is equipped with a supercharger such as a turbocharger for supercharging intake air to the engine (internal combustion engine) in order to increase the output of the engine. In a vehicle equipped with a turbocharger, the compressed air from the turbocharger flows back upstream during supercharging, and the airflow noise emitted from the intake pipe and intake port is perceived by passengers as an abnormal noise. A muffler is provided to suppress airflow noise.

For example, Japanese Patent Laid-Open No. 2002-100001 describes an intake system of an engine in which a resonator, which is a silencer, is provided. In this intake system, an air cleaner, a resonator, a turbocharger, which is a supercharger, and an intake manifold are arranged in this order from the upstream side in an intake passage of an engine. Air is introduced into the engine through the intake manifold.

The resonator has a resonance housing that forms a resonance chamber that communicates with the interior of the intake passage. This resonance chamber controls the flow of intake air and generates resonance in the resonance chamber to reduce airflow noise during supercharging. can be reduced.

JP-A-60-093123

However, the intake device described in Patent Document 1 has a problem that the pressure loss of the intake air increases due to the provision of the resonator, and the low power output of the engine is suppressed. At high revolutions, that is, in a high supercharging range where the supercharging pressure is high, pressure loss due to the resonator causes a problem that desired output performance cannot be obtained.

On the other hand, in the high supercharging range, the increase in engine noise makes it difficult for the passenger to perceive the intake noise as an abnormal noise. Therefore, there has been a demand for a structure capable of suppressing the pressure loss due to the resonator in the high supercharging region and exhibiting high output performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a noise reduction device for an internal combustion engine that can reduce airflow noise generated in a low supercharging pressure range and can obtain high output performance in a high supercharging range. for the purpose.

To achieve the above object, one embodiment of the present invention provides an intake manifold connected to an internal combustion engine, a supercharger disposed in an intake passage for introducing intake air into the intake manifold, and a supercharger in the intake passage. and a muffler for muffling intake noise, wherein the muffler constitutes a part of the intake passage and has a cylindrical communicating portion having a through hole in a peripheral wall thereof. a resonance housing provided outside the communication portion and forming a resonance chamber communicating with the inside of the communication portion through the through hole; and a vent pipe communicating the inside of the intake manifold with the inside of the resonance housing . and is arranged between the communicating portion and the resonance housing, and when the boost pressure of the intake air introduced into the resonance housing through the vent pipe is equal to or higher than a predetermined value, the communicating portion a movable member that moves in a circumferential direction or a cylindrical axial direction to displace from an open position that opens the through hole to a closed position that closes the through hole; and a biasing member , wherein the movable member is formed in a cylindrical shape that covers the entire circumference of the communicating portion with a gap from the outer peripheral surface of the communicating portion, and extends from the inner peripheral surface to the outer peripheral surface of the communicating portion. The muffler has an air chamber defined by the outer surface of the communication portion, the inner peripheral surface of the movable member, and the movable wall portion, and the air chamber through the ventilation pipe. The movable member is moved to the closing position by pressing the movable wall portion by the pressure of the intake air introduced into the air chamber .

According to this configuration, when the supercharging pressure of the intake air introduced into the resonance housing of the muffler from the intake manifold through the vent pipe is less than the predetermined value, that is, in the low supercharging region where the supercharging pressure becomes low. In this case, the intake air can be reduced by opening the through hole of the muffler and allowing the intake air to flow into the resonance chamber of the muffler. Further, when the supercharging pressure of the intake air introduced into the resonance housing of the muffler from the intake manifold through the vent pipe is equal to or higher than a predetermined value, that is, in the case of the high supercharging region where the supercharging pressure is high, the noise is muted. By closing the through hole of the device, intake air is prevented from flowing into the resonance chamber, thereby preventing intake pressure loss. As a result, high output performance can be obtained in the high supercharging region.

According to this configuration, the movable member can be moved by the pressure of the intake air introduced into the air chamber formed in the muffler through the vent pipe. A member can be moved.

In one embodiment of the present invention, in the silencer for an internal combustion engine, the communication portion has a plurality of through holes in the peripheral wall, and the movable member opens all the through holes at the open position, It is characterized in that all the through holes are closed at the closing position.

According to this configuration, it is possible to obtain high output performance by closing all the through holes with the movable member in the high supercharging region.

According to the noise reduction device for an internal combustion engine according to the present invention, it is possible to reduce the air flow noise generated in the low supercharging pressure region and obtain high output performance in the high supercharging region.

1 is an explanatory diagram showing a silencer for an internal combustion engine according to an embodiment of the present invention; FIG. FIG. 4 is a side view of the muffler with the movable member in the open position; FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 3 is a longitudinal sectional view of the silencer shown in FIG. 2; FIG. 4 is a cross-sectional view of the upstream side of the silencer 20 taken along line BB in FIG. 3 along the cylinder axis direction; FIG. 4 is a side view of the muffler with the movable member in the closed position; FIG. 7 is a cross-sectional view taken along line CC of FIG. 6;

FIG. 1 is an explanatory diagram showing a silencer for an internal combustion engine according to one embodiment of the present invention. A muffler 10 according to the present invention is applied to a vehicle such as an automobile, and includes a muffler 20 that reduces intake noise of intake air introduced into an engine (internal combustion engine) 12 . A muffler 10 of the present embodiment includes an engine 12, an intake device 14 that introduces intake air into the engine 12, and an exhaust device 16 that discharges exhaust from the engine 12. The muffler 20 is provided in the intake device 14. It is

The engine 12 supercharges intake air with a supercharger to achieve high output and low fuel consumption. For example, a small engine with a small displacement or a large engine with a large displacement is used. be able to. Furthermore, the engine type is not limited, and may be, for example, a horizontally opposed engine, an in-line engine, a V-type engine, or the like.

The intake device 14 includes an intake pipe 41 forming an intake passage 40. The intake pipe 41 includes, in order from the upstream side, an air cleaner 42, an air flow meter 44, a turbocharger 50 as a supercharger, a silencer 20, and a throttle valve. 45, an intercooler 46, an intake manifold 48, and the like are provided.

The air cleaner 42 is a filter that filters intake air to remove dust in the air. The airflow meter 44 is provided near the outlet of the air cleaner 22 and measures the amount of intake air passing through the intake pipe 41 .

The turbocharger 50 is a supercharger that is arranged between the intake pipe 41 and the exhaust pipe 61 of the exhaust device 16 and uses the energy of the exhaust gas from the engine 12 to compress and supercharge the intake air. The turbocharger 50 has a turbine 52 provided in the exhaust pipe 61 and a compressor 54 connected to the turbine 52 by a rotating shaft 53 and provided in the intake pipe 41 . The turbocharger 50 rotates a turbine 52 with exhaust gas from the engine 12 to drive a coaxial compressor 54 to compress intake air.

The muffler 20 reduces intake noise of intake air, and is specifically a resonator that muffles airflow noise by generating resonance. The muffler 20 is provided in the intake passage 40 in the vicinity of the turbocharger 50 , and in the present embodiment, is arranged in the intake passage 40 downstream of the turbocharger 50 and upstream of the throttle valve 45 . there is

2 is a side view of the muffler 20, FIG. 3 is a cross-sectional view along line AA in FIG. 2, FIG. 4 is a vertical cross-sectional view of the muffler 20 shown in FIG. 2, and FIG. FIG. 4 is a cross-sectional view taken along the line BB in FIG. 3 in the direction of the cylinder axis; The muffler 20 has a cylindrical communicating portion 21 that constitutes a part of the intake passage 40 and has at least one communicating hole (through hole) 22 that communicates with the outside in the peripheral wall, and the communicating portion 21 through the communicating hole 22 A resonance housing 25 forming a resonance chamber 28 communicating with the inside is provided, and an opening/closing mechanism for opening and closing the communication hole 22 is provided. In addition, in FIG. 2 and FIG. 6 described later, the resonance housing 25 is indicated by a chain double-dashed line so that the opening/closing mechanism can be easily understood. The opening/closing mechanism includes a movable member 31 , a biasing member 36 and a vent pipe 38 .

The communicating portion 21 is a part of the intake pipe 41 that forms the intake passage 40, and the communicating hole 22 is a hole penetrating the peripheral wall of the communicating portion. In the present embodiment, the outer peripheral surface 21a of the communicating portion 21 is formed with four protrusions 23 that protrude radially outward and extend in the cylinder axis direction. Two communicating holes 22 are formed. In the communication portion 21, the number of communication holes 22, the length of the communication holes 22, the size of the opening area of the communication holes 22, and the like can be appropriately set according to the frequency band of the intake noise to be silenced.

The resonance housing 25 is a housing provided outside the communication portion 21 and has a resonance chamber 28 inside which can communicate with the inside of the communication portion 21 . In the present embodiment, the resonance housing 25 is formed in a tubular shape surrounding the entire circumference of the communicating portion 21 so as to cover all the communicating holes 22 from the outside. It has a first end wall portion 26b that closes the upstream end opening of the surrounding wall portion 26a, and a second end wall portion 26c that closes the downstream end opening of the surrounding wall portion 26a. . In this embodiment, the communicating portion 21 and the resonance housing 25 are formed in a substantially cylindrical shape, but the cross-sectional shape is not limited to circular, and may be elliptical or polygonal.

A movable member 31 that constitutes an opening/closing mechanism is disposed between the resonance housing 25 and the communicating portion 21, and is movable with respect to the communicating portion 21 so as to open and close all the communicating holes 22 of the communicating portion 21. configured to

In this embodiment, the movable member 31 is formed in a tubular shape surrounding the entire circumference of the communicating portion 21 . Both ends of the movable member 31 are slidably in contact with the inner surfaces of the first end wall portion 26b and the second end wall portion 26c of the resonance housing 25. It is configured to be rotatable in the circumferential direction with respect to the housing 25 . As shown in FIGS. 3 and 4, the top surface of the projecting portion 23 of the communicating portion 21 is in contact with the inner peripheral surface of the movable member 31, and the peripheral wall of the movable member 31 has the communicating hole 22 of the communicating portion 21. Through holes 32 are formed at positions corresponding to . When the movable member 31 rotates in the circumferential direction, each through hole 32 overlaps with each communicating hole 22 of the communicating portion 21, and all the communicating holes 22 are in an open position (see FIGS. 2 to 4). ) and a closed position (see FIGS. 6 and 7) where all the communication holes 22 are closed.

A movable wall portion 33 is formed inside the movable member 31 so as to protrude from the inner peripheral surface 31 a of the movable member 31 to the outer peripheral surface 21 a of the communicating portion 21 . In the present embodiment, the movable wall portion 33 extends in the cylinder axis direction substantially parallel to the projecting portion 23 of the communicating portion 21, and both ends thereof are connected to the first end wall portion 26b and the second end of the housing 25 for resonance. It is in slidable contact with the inner surface of the wall portion 26c. As shown in FIG. 3 , between the communicating portion 21 and the movable member 31 are an inner peripheral surface 31 a and a movable wall portion 33 of the movable member 31 , an outer peripheral surface 21 a that is the outer surface of the communicating portion 21 , and a projecting portion 23 . A chamber partitioned by is formed. In the illustrated example, a first chamber (air chamber) 34 and a second chamber 35 partitioned by a movable wall portion 33 are formed between the projecting portions 23 adjacent in the circumferential direction.

The biasing member 36 applies a biasing force to the movable member 30 so as to hold the movable member 30 at the open position. As shown in FIG. 3, the biasing member 36 of this embodiment is a coil spring and is arranged in each first chamber 34 . One end of the coil spring is connected to the projecting portion 23 of the communicating portion 21, and the other end is connected to the movable wall portion 33. As the coil spring expands and contracts, the movable member 30 rotates in the circumferential direction.

The vent pipe 38 is a pipe that communicates between the intake manifold 48 and the first chamber 34 formed in the resonance housing 25 . As shown in FIGS. 2 and 5, the vent pipe 38 has a plurality of branched ends on the resonance housing 25 side, and each branch passage communicates with each first chamber 34 in the silencer 20, It does not communicate with the second chamber 35 . 5, illustration of the biasing member 36 in the first chamber 34 is omitted. Part of the intake air that has flowed into the intake manifold 48 through the intercooler 46 is introduced into the first chamber 34 of the muffler 20 through the ventilation pipe 38 .

The spring constant of the biasing member 36 is determined when the internal pressure of the first chamber 34 reaches or exceeds a predetermined value, specifically, when the supercharging pressure of the intake air supercharged by the turbocharger 50 reaches or exceeds a predetermined value. Further, the movable wall portion 33 is pushed toward the second chamber 34 against the biasing force of the biasing member 36 by the pressure inside the chamber, and the movable member 31 is set to move to the closed position. Note that the value of the supercharging pressure, which is the reference for moving the movable member 31, can be appropriately set according to the turbocharger 50 to be used.

The throttle valve 45 adjusts the amount of intake air and is arranged downstream of the muffler 20 . The throttle opening of the throttle valve 45 is adjusted by an actuator (not shown) according to the driver's operation of the accelerator pedal or the like.

The intercooler 46 is a heat exchanger that is arranged downstream of the compressor 54 and cools the air that has been compressed by the compressor 54 and heated to a high temperature. In the illustrated example, the intercooler 46 is arranged downstream of the throttle valve 45 , but the intercooler 46 may be arranged between the silencer 46 and the throttle valve 45 .

The exhaust system 16 includes an exhaust pipe 61 forming an exhaust passage 60, and an exhaust manifold 62, a turbine 52, and the like are arranged in order from the upstream side (engine 12 side). The exhaust system 16 further has an exhaust bypass pipe 64 that communicates between the upstream side and the downstream side of the turbine 52 . The exhaust bypass pipe 64 is provided with a wastegate valve 65 and an actuator 66 that adjusts the opening of the wastegate valve 65 . The supercharging pressure can be controlled by adjusting the amount of displacement.

In the silencer 10 described above, the air sucked through the air cleaner 42 is supercharged by the turbocharger 50 , passed through the silencer 20 , throttled by the throttle valve 45 , and cooled by the intercooler 46 . Cooled intake air is introduced into the engine 12 via an intake manifold 48 and drawn into each cylinder formed in the engine 12 . In each cylinder, a mixture of intake air and fuel is combusted, and exhaust gas after combustion is discharged to an exhaust pipe 61 via an exhaust manifold 62 .

Next, the operation of the muffler 20 of the muffler 10 will be described.

When the muffler 20 is not supercharged or in a low supercharging pressure region where the supercharging pressure by the turbocharger 50 is less than a predetermined value, the movable member 31 is held at the open position side by the biasing member 36. Thus, the inside of the communication portion 21 and the resonance chamber 27 are brought into communication with each other through the communication hole 22 and the through hole 32 . As a result, the muffler 20 is turned on as shown in FIGS. 2 to 4 to muffle the intake sound by resonance.

Intake noise (turbo airflow noise) during supercharging by the turbocharger 50 is likely to be perceived as an abnormal noise by the occupant, especially when the boost pressure rises. Since the silencer 10 is turned on in the low supercharging region, the turbo airflow noise can be appropriately silenced.

On the other hand, in a high supercharging pressure region where the supercharging pressure by the turbocharger 50 is equal to or higher than a predetermined value, the silencer 20 reduces the pressure of the intake air introduced into the first chamber 34 from the intake manifold 48 through the ventilation pipe 38. pushes the movable wall portion 33 toward the second chamber 35 so that the first chamber 34 expands. As a result, the movable member 31 moves to the closed position against the urging force of the urging member 36, and the muffler 20 enters an OFF state in which all the communication holes 21 are closed, as shown in FIGS. Become. In the OFF state, intake air introduced from the intake manifold 48 into the first chamber 34 is also introduced into the resonance chamber 28 through the through hole 32 . The volume of the second chamber 35 is reduced as the volume of the first chamber 34 is expanded. Since the muffler 20 is turned off, intake pressure loss in the muffler 20 is prevented, and the output performance of the engine 12 is kept high.

In a high supercharging region where the boost pressure rises and the engine 12 rotates at high speed, vehicle power noise is generated in addition to the turbo airflow noise, so the turbo airflow noise is less likely to be perceived as an abnormal noise by the occupants. The muffler 10 can obtain high output performance by turning off the muffler 20 in this high supercharging region and prioritizing the output performance of the engine 12 .

As described above, the muffler 10 can switch on and off the muffler 20 using the supercharging pressure, so it does not require complicated control, and achieves both muffling performance and output performance with a simple structure. It is possible. In recent years, attention has been focused on a so-called downsizing turbo technology, in which an internal combustion engine is downsized (reduced displacement) and supercharged by a turbocharger to improve fuel efficiency. It can be suitably used for an internal combustion engine equipped with a supercharger.

Further, the silencer 10 has a spring constant of the biasing member 36 so that the opening of the communication hole 22 changes stepwise according to the supercharging pressure when the movable member 31 moves from the open position to the closed position. Also, the arrangement of the communication holes 22 and the through holes 32 can be adjusted as appropriate. As a result, the effective frequency of the muffler 20 can be changed according to the boost pressure, and the muffling performance can be further improved.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the invention.

For example, the muffler 20 may be arranged in the intake passage 40 upstream of the turbocharger 50, or may be arranged between the air flow meter 44 and the compressor 54 in the intake device 14 shown in FIG. .

By appropriately changing the shape of the air chamber 37 and the arrangement of the urging member 36, the movable member 30 can be configured to move in the direction of the cylindrical axis of the communicating portion 21 to open and close the through hole 22. FIG.

Further, in the above-described embodiment, the turbocharger 50 is used as the supercharger, but instead of this, for example, other types of supercharger such as a supercharger can be used.

10 silencer 12 engine (internal combustion engine)
14 intake device 16 exhaust device 20 muffler 22 communication hole (through hole)
25 housing for resonance 28 resonance chamber 31 movable member 32 through hole 33 movable wall portion 34 first chamber (air chamber)
35 Second Chamber 36 Biasing Member 38 Ventilation Pipe 40 Intake Passage 48 Intake Manifold 50 Turbocharger

Claims (2)

an intake manifold coupled to an internal combustion engine;
a turbocharger disposed in an intake passage that introduces intake air into the intake manifold;
A muffler for an internal combustion engine comprising a muffler disposed in the intake passage for muffling intake noise,
The silencer is
a tubular communicating portion forming a part of the intake passage and having a through hole in a peripheral wall thereof;
a resonance housing that is provided outside the communicating portion and forms a resonance chamber that communicates with the inside of the communicating portion through the through hole;
a vent pipe communicating between the intake manifold and the resonance housing ;
It is disposed between the communicating portion and the resonance housing, and is provided in a circumferential direction with respect to the communicating portion when boost pressure of intake air introduced into the resonance housing through the vent pipe is equal to or higher than a predetermined value. a movable member that moves in a direction or in a cylinder axis direction and displaces from an open position that opens the through hole to a closed position that closes the through hole;
a biasing member biasing the movable member to hold it in the open position ;
The movable member is formed in a cylindrical shape that covers the entire circumference of the communicating portion with a gap from the outer peripheral surface of the communicating portion, and has a movable wall portion that extends from the inner peripheral surface to the outer peripheral surface of the communicating portion,
The muffler has an air chamber defined by the outer surface of the communication portion, the inner peripheral surface of the movable member, and the movable wall portion, and the intake air introduced into the air chamber through the ventilation pipe is exhausted. A muffler for an internal combustion engine, wherein the movable wall portion is pressed by pressure to move the movable member to the closed position . The communicating portion has a plurality of through holes in the peripheral wall,
2. A muffler for an internal combustion engine according to claim 1 , wherein said movable member opens all through holes at said open position and closes all through holes at said closed position.

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