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US 6,633,646 B1Granted
Method and apparatus for controlling exhaust noise
AssigneeKorea Institute of Science and Technology
InventorYoha Hwang
Life of this patent
Estimating the term…
Abstract
The present invention relates to noise reduction technology for controlling exhaust noise in internal combustion engines such as an automobile engine and/or noise in a duct of an air delivery system such as air conditioning systems, and more particularly, to an apparatus and a method for controlling exhaust noise in an internal combustion engine or noise in a duct of an air delivery system using a conduit bypass pipe having variable or fixed lengths and dual mufflers.
Claims19
An apparatus for controlling exhaust noise from an internal combustion engine, comprising:
- a main exhaust pipe;
- a first bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a first bypass section is defined in the passage of said main exhaust pipe, and two air delivering passages each passing through each of the two connection points for said main exhaust pipe and the first bypass pipe are formed thereby;
- a second bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a second bypass section is defined in the passage of said main exhaust pipe, and two air delivering passages each passing through each of the two connection points for said main exhaust pipe and the second bypass pipe are formed thereby;
- first and second actuators adapted to be actuated to vary the length of said first and second bypass pipes, respectively;
- a controller for controlling said first actuator to select the length of said first bypass pipe so that the lengths of said two air delivering passages passing through said two connection points of said main exhaust pipe and said first bypass pipe differ from each other by a half wavelength of a main noise component occurring in said internal combustion engine, and for controlling said second actuator to select the length of said second bypass pipe so that the lengths of said two air delivering passages passing through said two connection points of said main exhaust pipe and said second bypass pipe differ from each other by a half wavelength of a noise component having a frequency of two times the frequency of the main noise component occurring in said internal combustion engine;
- a lower back pressure muffler installed downstream of said main exhaust pipe;
- and
- a higher back pressure muffler provided separately from said lower back pressure muffler;
- such that when the engine revolutions per minute are higher than a predetermined value, said main noise component and said noise component having a frequency of two times the frequency of said main noise component are eliminated at said two connection points of each of said main exhaust pipe and said first and second bypass pipes, and the remaining noises of other wide frequencies pass through said lower back pressure muffler, and when the engine revolution per minute is lower than the predetermined value, the exhaust noise passes through the higher back pressure muffler.
6 more elements
An active exhaust noise control apparatus, comprising:
- a main exhaust pipe 11, a bypass pipe 12 having variable length and connected to said main exhaust pipe 11 at both ends thereof so that a bypass section is defined in the passage of the main exhaust pipe 11, an actuator 14 being actuated so as to vary the length of said bypass pipe 12 by varying the length of the actuating rod 14a, and a controller 21 for controlling said actuator 14,
- said apparatus further comprises a lower back pressure muffler 18 and a higher back pressure muffler 19 which are bifurcated and installed downstream of the main exhaust pipe 11, and a valve 20 for selectively communicating the main exhaust pipe 11 with two mufflers 18 and 19, and said valve 20 is controlled by said controller 21.
A noise control apparatus for controlling noise inside a duct of an air delivering system, comprising:
- a main air delivering duct 15, a first bypass duct 53 of which both ends are connected to said air delivering duct 51 so that a first bypass section is defined in the passage of the air delivering duct 51, a second bypass duct 55 of which both ends are connected to said main air delivering duct 51 so that a second bypass section is defined in the passage of the main air delivering duct 51,
- wherein the length of the first bypass duct 53 is selected so that the lengths of the two air delivering passages passing through the two connection points of the main air delivering duct 51 and the bypass duct 53 differs from each other by a half wavelength of the main noise component occurring in the gas delivering system, and
- wherein the length of the second bypass duct 55 is selected so that the lengths of the two air delivering passages passing through the two connection points of the main air delivering duct 51 and the bypass duct 55 differs from each other by a half wavelength of component having a frequency of two times the frequency of the main noise components occurring in the air delivering system.
A method for controlling exhaust noise from an internal combustion engine, comprising the steps of:
- analyzing a main noise component passing through a main exhaust pipe with a controller;
- actuating a first actuator with said controller to select a length of a first bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the first bypass pipe differ from each other by a half wavelength of said main noise component to eliminate said main noise component and noise components having frequencies multiplied by odd integers to the frequency of said main noise component;
- actuating a second actuator with said controller to select a length of a second bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the second bypass pipe differ from each other by a half wavelength of a noise component having a frequency of two times the frequency of said main noise component to eliminate the noise component having a frequency of two times the frequency of said main noise component;
- and
- controlling a valve with said controller to communicate said main exhaust pipe with a lower back pressure muffler at an engine rotation speed higher than a predetermined value so that remaining noises of other wide frequencies pass through the lower back pressure muffler, and to communicate said main exhaust pipe with a higher back pressure muffler at one of an engine rotation speed lower than a predetermined value and upon cold starting said engine so that the exhaust noise passes through the higher back pressure muffler.
2 more elements
A method for controlling exhaust noise from an internal combustion engine, comprising the steps of:
- analyzing a main noise component passing through a main exhaust pipe with a controller;
- actuating a first actuator with said controller to select a length of a first bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the first bypass pipe differ from each other by a half wavelength of said main noise component to eliminate said main noise component and noise components having frequencies multiplied by odd integers to the frequency of said main noise component;
- actuating a second actuator with said controller to select a length of a second bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the second bypass pipe differ from each other by a half wavelength of a noise component having a frequency of two times the frequency of said main noise component to eliminate the noise component having a frequency of two times the frequency of said main noise component;
- and
- actuating a dual mode muffler to operate as a lower back pressure muffler at an engine rotation speed higher than a predetermined value, and as a higher back pressure muffler at one of an engine rotation speed lower than a predetermined value and upon cold starting said engine.
2 more elements
A method for controlling exhaust noise from an internal combustion engine, comprising the steps of:
- actuating a valve at an engine rotation speed higher than a predetermined value such that exhaust noise passes through a main exhaust pipe, and at an engine rotation speed lower than a predetermined value or cold starting said engine such that exhaust noise passes through a second exhaust pipe and a higher back pressure muffler;
- analyzing a main noise component passing through the main exhaust pipe with a controller;
- actuating a first actuator with said controller to select a length of a first bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the first bypass pipe differ from each other by a half wavelength of said main noise component to eliminate said main noise component and noise components having frequencies multiplied by odd integers to the frequency of said main noise component;
- actuating a second actuator with said controller to select a length of a second bypass pipe such that the lengths of two air delivering passages each passing through one of two connection points of said main exhaust pipe with the second bypass pipe differ from each other by a half wavelength of a noise component having a frequency of two times the frequency of said main noise component to eliminate the noise component having a frequency of two times the frequency of said main noise component;
- and
- passing remaining noises of other wide frequencies through a lower back pressure muffler.
3 more elements
A method for controlling exhaust noise from an internal combustion engine, comprising the steps of:
- analyzing a main noise component with a controller;
- actuating an actuator with said controller to adjust a length of a bypass pipe such that said main noise component and noise components having frequencies of two times the frequency of said main noise component or multiplied by odd integers to the frequency of said main noise component, are removed;
- and
- controlling a valve with said controller to communicate a main exhaust pipe with a lower back pressure muffler at an engine rotation speed higher than a predetermined value such that remaining noises of other wide frequencies pass through the lower back pressure muffler, and to communicate the main exhaust pipe with a higher back pressure muffler at an engine rotation speed lower than a predetermined value or cold starting said engine such that exhaust noise passes through the higher back pressure muffler.
1 more element
An apparatus for controlling exhaust noise from an internal combustion engine, comprising:
- a main exhaust pipe;
- a first bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a first bypass section is defined in a passage of said main exhaust pipe, and two air delivering passages each passing through each of the two connection points for said main exhaust pipe and the first bypass pipe are formed thereby;
- a second bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a second bypass section is defined in the passage of said main exhaust pipe;
- a first and second actuators adapted to be actuated to vary the length of said first and second bypass pipes, respectively;
- and
- a controller for controlling said first actuators wherein said apparatus further comprises a lower back pressure muffler and a higher back pressure muffler bifurcated downstream of the main exhaust pipe, and a valve for selectively communicating the main exhaust pipe with the two mufflers and, and wherein said valve is controlled by the controller.
3 more elements
An apparatus for controlling exhaust noise from an internal combustion engine, comprising:
- a main exhaust pipe;
- a first bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a first bypass section is defined in the passage of said main exhaust pipe;
- connection points for said main exhaust pipe and the first bypass pipe are formed thereby;
- a second bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a second bypass section is defined in the passage of said main exhaust pipe;
- first and second actuators adapted to be actuated to vary the length of said first and second bypass pipes, respectively;
- and
- a controller for controlling said first and second actuators
- wherein said apparatus comprises a dual mode type muffler which is installed downstream of the main exhaust pipe and is controlled by the controller so as to be selectively actuated to function as one of a higher back pressure muffler and a lower back pressure muffler.
5 more elements
An apparatus for controlling exhaust noise from an internal combustion engine, comprising:
- a main exhaust pipe;
- a first bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a first bypass section is defined in the passage of said main exhaust pipe;
- a second bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a second bypass section is defined in the passage of said main exhaust pipe;
- first and second actuators adapted to be actuated to vary the length of said first and second bypass pipes, respectively;
- wherein said apparatus comprises a double mode type muffler which is installed downstream of the main exhaust pipe and is selectively actuated as one of a high back pressure muffler and a low back pressure muffler in accordance with the exhaust gas pressure.
2 more elements
An apparatus for controlling exhaust noise from an internal combustion engine, comprising:
- a main exhaust pipe;
- a first bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a first bypass section is defined in a passage of said main exhaust pipe;
- a second bypass pipe having a length which is variable and connected to said main exhaust pipe at both ends thereof so that a second bypass section is defined in the passage of said main exhaust pipe;
- first and second actuators adapted to be actuated to vary the length of said first and second bypass pipes, respectively;
- and
- a controller for controlling said first and second actuators;
- wherein said apparatus further comprises a second exhaust pipe bifurcated upstream of the first bypass pipe from the main exhaust pipe, and a valve for selectively communicating two exhaust gas passages defined by the main exhaust pipe and the second exhaust pipe, and wherein said valve is controlled by the controller.
4 more elements
Dependencies are inferred from the claim text.