US20160273424A1

US20160273424A1 - Mounting structure of variable valve for dual exhaust system

Info

Publication number: US20160273424A1
Application number: US14/955,943
Authority: US
Inventors: Hak-Son Han
Original assignee: Hyundai Motor Co
Current assignee: Hyundai Motor Co
Priority date: 2015-03-19
Filing date: 2015-12-01
Publication date: 2016-09-22
Also published as: DE102015121071A1; CN105986854A

Abstract

A mounting structure of a variable valve for a dual exhaust system may include a muffler, at a front end of which is connected a first inlet pipe, and at a rear end of which is connected a first outlet pipe, and a Helmholtz Resonator, at the front end of which is connected a second inlet pipe, and at a rear end of which is connected a second outlet pipe, in which a variable valve which is opened and closed by an Electronic Control Unit (ECU) of a car is disposed on the second outlet pipe connected to the Helmholtz Resonator.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2015-0037918 filed Mar. 19, 2015, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a mounting structure of variable valve for dual exhaust system. More particularly, the present invention relates to a mounting structure of variable valve for dual exhaust system in which a Helmholtz Resonator is formed to be relatively small compared to a muffler and a variable valve is mounted at the rear end of the Helmholtz Resonator so that a second outlet pipe is selectively opened and closed, whereby the reduction of the booming noise and the maximization of the power performance can be achieved at the same time and the production cost can be significantly reduced.
2. Description of Related Art
The noise entered into the inside of the car is caused by a variety of factors such as engine driving, road surface bending, or wind flowed into the car during travel, and a variety of devices are used to reduce the noise.
In particular, since the exhaust gas combusted in the inside of the engine of the car is considerably high temperature and the velocity thereof almost amounts to the speed of sound so that if it is discharged into the atmosphere as it is, then it is abruptly expanded and produces the violent sound, a separate muffler is mounted on the exhaust gas path of the car to lower the temperature and the pressure of the exhaust gas so as to reduce the exhaust sound.
In general, a muffler is formed in the form of barrel of a predetermined size, and inside thereof are mounted a plurality of pipes and baffles so that the exhaust sound can be lowered by inducing the expansion, resonance and the sound absorption of the exhaust gas at a time of flow of the exhaust gas.
Meanwhile, this muffler has a problem in that if the exhaust gas resistance is raised to reduce the exhaust sound, the resistance applied to the exhaust gas stroke, that is, the back pressure is raised so that the output of the engine is lowered, and to the contrary, if the exhaust gas resistance is lowered to prevent the output loss of the engine, the exhaust sound is increased.
To solve such a problem, a muffler installed with a variable valve is developed and used to raise the back pressure in the low speed interval in which the exhaust sound becomes a problem and to lower the back pressure in the middle and high speed intervals in which the engine output becomes a problem.
FIG. 1 is a top view showing a conventional mounting structure of variable valve for dual exhaust system.
As shown in FIG. 1, the conventional dual exhaust system comprises a first inlet pipe 1 and a second inlet pipe 1′ which are branched into two pipes so that the exhaust gas discharged from the engine of the car can be flowed, a first muffler 2 and a second muffler 2′ reducing the exhaust sound by being respectively connected to the first inlet pipe and the second inlet pipe, and a first outlet pipe 3 and a first outlet pipe 3′ each discharging the exhaust gas having passed the first muffler and the second muffler to the outside of the car.
At this time, a first variable valve 4 and a second variable valve 4′ which are controlled by the Electronic Control Unit (ECU) of the car are respectively installed on the first outlet pipe 3 and the second outlet pipe 3′ so as to differentiate the level of the exhaust sound and the back pressure according to the travel condition of the car.
However, the conventional mounting structure of variable valve for dual exhaust system has the problem in that, since the first variable valve 4 and the second variable valve 4′ should be respectively installed on both sides of the first outlet pipe 3 and the second outlet pipe 3′, there is a difficulty in the respect of production cost.
In addition, there are problems in that the conventional first variable valve 4 and the second variable valve 4′ are respectively installed in the space between the first muffler 2 and the first tail pipe 5 and in the space between the second muffler 2′ and the second tail pipe 5′ so that the composition of the package is difficult, and the entire size of the muffler 2, 2′ is reduced to prepare the installation space for the variable valves 4, 4′.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a mounting structure of variable valve for dual exhaust system in which one variable valve is installed only at the rear end of the Helmholtz Resonator unlike the prior art so that the production cost and the car weight are significantly reduced.
Furthermore, various aspects of the present invention are directed to providing a mounting structure of variable valve for dual exhaust system in which, although only one variable valve is installed, the booming noise is significantly reduced compared to the conventional car and the power performance is maximized.
According to various aspects of the present invention, a mounting structure of a variable valve for a dual exhaust system may include a muffler, at a front end of which is connected a first inlet pipe, and at a rear end of which is connected a first outlet pipe, and a Helmholtz Resonator, at the front end of which is connected a second inlet pipe, and at a rear end of which is connected a second outlet pipe, in which a variable valve which is opened and closed by an Electronic Control Unit (ECU) of a car may be disposed on the second outlet pipe connected to the Helmholtz Resonator.
The Helmholtz Resonator may be constructed to have relatively small size than the muffler so that the muffler and the Helmholtz Resonator are arranged asymmetrically.
The Helmholtz Resonator may include a housing, into an inside of which exhaust gas flows and a rear end of which is opened, a first baffle arranged transversely in the housing, a second baffle combined transversely to close the rear end of the housing, and a resonant chamber partitioned by the first baffle and the second baffle.
At a time of low load travel of the car, the second outlet pipe may be closed by the variable valve and the exhaust gas may flow in the second inlet pipe and an inside of the Helmholtz Resonator so that a booming noise of the car is significantly reduced.
At a time of high load travel of the car, the second outlet pipe may be opened by the variable valve and the exhaust gas may be discharged to an outside of the car through the first outlet pipe and the second outlet pipe.
It is understood that the term “vehicle” or “vehicular” or other similar terms as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuel derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example, both gasoline-powered and electric-powered vehicles.
The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a conventional mounting structure of variable valve for dual exhaust system according to the related art.

FIG. 2A and FIG. 2B are top views showing an entire configuration of an exemplary mounting structure of variable valve for dual exhaust system according to the present invention.

FIG. 3 is a perspective view showing the configuration of the exemplary variable valve according to the present invention.

FIG. 4 is a projective top view showing a configuration of Helmholtz Resonator according to the present invention.

FIG. 5 shows graphs comparing a result of analysis of transmission loss varying upon opening/closing of the variable valve according to the present invention.

FIG. 6 shows graphs comparing a tail pipe noise varying upon opening/closing of the variable valve according to the present invention.

FIG. 7 shows graphs comparing an exhaust sound of the exemplary mounting structure of variable valve for dual exhaust system according to the present invention and an exhaust sound of the conventional mounting structure of variable valve for dual exhaust system at the time of slow acceleration of a car.

FIG. 8 shows graphs comparing an exhaust sound of the exemplary mounting structure of variable valve for dual exhaust system according to an the present invention and an exhaust sound of the conventional mounting structure of variable valve for dual exhaust system at the time of rapid acceleration of the car.

FIG. 9 shows graphs comparing pressure of the exemplary mounting structure of variable valve for dual exhaust system according to the present invention and back pressure of the conventional mounting structure of variable valve for dual exhaust system.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
FIG. 2A and FIG. 2B are top views showing the entire configuration of the mounting structure of variable valve for dual exhaust system according to various embodiments of the present invention, FIG. 3 is a perspective view showing the configuration of the variable valve according to various embodiments of the present invention, and FIG. 4 is a projective top view showing the configuration of the Helmholtz Resonator according to various embodiments of the present invention.
As shown in FIG. 2A and FIG. 2B, the exhaust gas discharged from an engine of the car flows into the muffler 10 and the Helmholtz Resonator 20 through the first inlet pipe 11 and the second inlet pipe 21 branched into two pipes.
In various embodiments, the first inlet pipe 11 is arranged at the left hand of the car and the second inlet pipe 21 is arranged at the right hand of the car, and in the likewise manner, the muffler 10 is arranged at the left hand of the car and the Helmholtz Resonator 20 is arranged at the right of the car, however, the reverse configuration is also possible.
The first outlet pipe 12 and the second outlet pipe 22 are connected to the rear end of the muffler 10 and the Helmholtz Resonator 20 respectively, and the first outlet pipe 12 and the second outlet pipe 22 play role of discharging the exhaust gas, which passed the muffler 10 and the Helmholtz Resonator 20, to the outside of the car.
The inside of the muffler 10 is partitioned by a number of baffles likewise the typical muffler, and in the muffler 10 are arranged the first inlet pipe 11, the first outlet pipe 12 and the middle pipe 13 in consideration of the flow of the exhaust gas.
On the second outlet pipe 22 connected to the Helmholtz Resonator 20 is installed a variable valve 30 which opens and closes the second outlet pipe 22 by being controlled by an Electric Control Unit (ECU) of the car.
At this time, unlike in the conventional structure of dual exhaust system the variable valves (4, 4′ of FIG. 1) are arranged at both outlet pipes (3, 3′ of FIG. 1), in the structure of dual exhaust system according to the present invention, the variable valve 30 is mounted only at the second outlet pipe 22.
This is possible since, unlike the prior art, in the present invention, on both sides are not installed identical mufflers (2, 2′ of FIG. 1), but on one side is installed the muffler 10 and on the other side is installed the Helmholtz Resonator 20.
As shown in FIG. 3, the variable valve 30 comprises a rotational motor 31 which is actuated by the ECU according to the travel condition (car speed, load and the like) of the car, and a valve cover 32 of the form of the circular plate which is rotated according to the actuation of the rotational motor.
Specifically, at the time of low load travel of the car (low speed travel, low acceleration travel, downward slope travel and the like), the rotational motor 31 is actuated so that the valve cover 32 coincides with the section of the second outlet pipe 22 so as to not allow the exhaust gas to pass.
On the contrary, at the time of high load travel of the car (high speed travel, rapid acceleration travel, upward slope travel and the like), the rotational motor 31 is actuated so that the valve cover 32 is arranged perpendicular to the section of the second outlet pipe 22 so as to allow the exhaust gas to pass.
At this time, since the Helmholtz Resonator 20 is constructed to have relatively small size than the muffler 10 so that the muffler 10 and the Helmholtz Resonator 20 are arranged asymmetrically, in the present invention, it is not necessary to reduce the size of the muffler 10 to install the variable valve 30.
Thinking in reverse, the muffler 10 according to the present invention may be formed to be further larger than the conventional muffler (2, 2′ of FIG. 1), and accordingly the designer of the muffler 10 can design the muffler 10 to realize the optimum noise characteristics without having limitation of layout.
As shown in FIG. 4, the Helmholtz Resonator 20 comprises a housing 23 into inside of which the exhaust gas flows and the rear end of which is opened, a first baffle 24 arranged transversely in the housing, a second baffle 25 combined transversely to close the rear end of the housing, and a resonant chamber 26 partitioned by the first baffle 24 and the second baffle 25.
The Helmholtz Resonator was devised by Helmholtz a German physiologist to separate a single sound from a complex sound and is widely used in mechanical system to reduce the flow noise in the duct.
In general, the resonator includes a cavity of significantly large volume and a neck, and the narrow band noise is reduced by making the resonant frequency, which is determined by the geometrical information of the cavity and the neck, consistent with the noise frequency of the duct.
In various embodiments, at the time of low load travel of the car, the second outlet pipe 22 is closed by the variable valve 30, the resonant chamber 26 plays the role of the cavity, and the second inlet pipe 21 plays the role of the neck, so that accordingly the booming noise of the exhaust gas passing through the inside of the muffler 10 is significantly reduced.
At the time of high load travel of the car, the second outlet pipe 22 is opened by the variable valve 30, and the exhaust gas is discharged to the outside through the first outlet pipe 12 and the second outlet pipe 22, whereby the power performance of the car is improved.
That is, the Helmholtz Resonator 20 according to the present invention plays the role of low frequency resonator at the time of low load travel of the car, and plays the role of the muffler in which the flow path is expanded and the back pressure is significantly reduced at the time of low load travel of the car.
At this time, the second outlet pipe 22 is formed in the linear shape unlike the outlet pipe used in the conventional typical muffler, so that the exhaust gas can be directly discharged, thereby having a significant effect in reducing the back pressure at the time of high load travel.
FIG. 5 shows graphs comparing the result of analysis of transmission loss varying upon opening/closing of the variable valve according to various embodiments of the present invention, and FIG. 6 shows graphs comparing the tail pipe noise varying upon opening/closing of the variable valve according to various embodiments of the present invention.
In general, the capacity of noise reduction is represented by the transmission loss curve obtained at the frequency zone, and to achieve the effective noise reduction, the peak frequency of the transmission loss curve should be consistent with the noise frequency.
As shown in FIG. 5, when comparing the transmission loss curve at the time of closing the variable valve 30 according to the present invention with the transmission loss curve at the time of opening the variable valve 30, it can be seen that the transmission loss curve at the time of closing the variable valve 30 has peak value at the low frequency zone.
That is, it can be seen that if the variable valve 30 is closed, the Helmholtz Resonator 20 has the effective noise reduction characteristics in the low frequency zone, and accordingly the booming noise of the car is reduced.
This is more obvious from the graphs comparing the tail pipe noise shown in FIG. 6. As shown in FIG. 6, it can be seen that the tail pipe noise at the time of closing the variable valve 30 in the low Revolution Per Minute (RPM) stage is significantly reduced compared to the tail pipe noise at the time of opening the variable valve 30, and accordingly the starting booming noise of the car is significantly reduced.
FIG. 7 shows graphs comparing the exhaust sound of the mounting structure of variable valve for dual exhaust system according to various embodiments of the present invention and the exhaust sound of the conventional mounting structure of variable valve for dual exhaust system at the time of slow acceleration of the car, FIG. 8 shows graphs comparing the exhaust sound of the mounting structure of variable valve for dual exhaust system according to various embodiments of the present invention and the exhaust sound of the conventional mounting structure of variable valve for dual exhaust system at the time of rapid acceleration of the car, and FIG. 9 shows graphs comparing the back pressure of the mounting structure of variable valve for dual exhaust system according to various embodiments of the present invention and the back pressure of the conventional mounting structure of variable valve for dual exhaust system.
Specifically, FIG. 7 shows the graphs comparing the exhaust sound in the condition of Accelerator Position Sensor (APS) 30% when applying the mounting structure of variable valve for dual exhaust system according to the present invention and the conventional mounting structure of variable valve for dual exhaust system to the real car.
As shown in FIG. 7, it can be seen that, at the time of slow acceleration of the car, the structure according to the present invention has the effect that the starting booming noise is reduced by about 10% in the low RPM zone (about 2000 RPM or below) compared to the conventional structure, and the acceleration linearity (shown in dotted line in FIG. 7) is secured so that there is the effect in favor of the realization of the dynamic sound quality.
FIG. 8 shows the graphs comparing the exhaust sound in the condition of WOP (Wide Open Throttle) when applying the mounting structure of variable valve for dual exhaust system according to the present invention and the conventional mounting structure of variable valve for dual exhaust system to the real car.
As shown in FIG. 8, at the time of rapid acceleration of the car, the structure according to the present invention has the effect that the dynamic exhaust gas sound quality and the power performance are maximized in the high RPM zone (about 2000 RPM or above) compared to the conventional structure.
Furthermore, as shown in FIG. 9, even when reviewing the back pressure according to the flow rate of the exhaust gas, the structure according to the present invention has the effect that the back pressure is significantly reduced compared to the conventional structure.
Therefore, regardless of the fact that the present invention uses one variable valve 30, the present invention has the improved effect in all respect compared to the structure using two conventional variable valves (4, 4′ in FIG. 1) that the starting booming noise is reduced in the low RPM zone and the power performance is improved in the high RPM zone.
The present invention having the structure described above has the effect of reducing the production cost and the car weight by installing one variable valve only on the second outlet pipe 22 connected to the rear end of the Helmholtz Resonator 20 compared to installing the variable valves on both sides.
Furthermore, the present invention has the advantage in that since the Helmholtz Resonator 20 is formed to have relatively small size than the muffler 10 so that the muffler 10 and the Helmholtz Resonator 20 are arranged asymmetrically, it is not necessary to reduce the size of the muffler to install the variable valve.
In addition, the present invention has the effect that although the variable valve 30 is installed only on the Helmholtz Resonator 20, the second inlet pipe 22 and the Helmholtz Resonator 20 play the role of low frequency resonator at the time of low load travel (at the time of slow acceleration) so that the booming noise is significantly reduced compared to the prior art.
Furthermore, the present invention has the effect that the variable valve installed on the Helmholtz Resonator is opened so that the sectional area of the outlet pipe is increased at the time of high load travel (at the time of rapid acceleration), whereby the power performance of the car and the dynamic exhaust sound quality are maximized compared to the prior art.
As a conclusion, in the present invention, there occurs the effect that the production cost and the car weight are reduced compared to the prior art and at the same time the exhaust gas performance and the power performance are improved so that the marketability of the car is increased.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

Claims

What is claimed is:

1. A mounting structure of a variable valve for a dual exhaust system comprising:

a muffler, at a front end of which is connected a first inlet pipe, and at a rear end of which is connected a first outlet pipe; and

a Helmholtz Resonator, at the front end of which is connected a second inlet pipe, and at a rear end of which is connected a second outlet pipe;

wherein a variable valve which is opened and closed by an Electronic Control Unit (ECU) of a car is disposed on the second outlet pipe connected to the Helmholtz Resonator.

2. The mounting structure of the variable valve for the dual exhaust system of claim 1, wherein the Helmholtz Resonator is constructed to have relatively small size than the muffler so that the muffler and the Helmholtz Resonator are arranged asymmetrically.

3. The mounting structure of the variable valve for the dual exhaust system of claim 1, wherein the Helmholtz Resonator comprises:

a housing, into an inside of which exhaust gas flows and a rear end of which is opened;

a first baffle arranged transversely in the housing;

a second baffle combined transversely to close the rear end of the housing; and

a resonant chamber partitioned by the first baffle and the second baffle.

4. The mounting structure of the variable valve for the dual exhaust system of claim 1, wherein, at a time of low load travel of the car, the second outlet pipe is closed by the variable valve and the exhaust gas flows in the second inlet pipe and an inside of the Helmholtz Resonator so that a booming noise of the car is significantly reduced.

5. The mounting structure of the variable valve for the dual exhaust system of claim 1, wherein, at a time of high load travel of the car, the second outlet pipe is opened by the variable valve and the exhaust gas is discharged to an outside of the car through the first outlet pipe and the second outlet pipe.