Exhaust silencer
An exhaust silencer includes a flow pipe supported in a housing. A space is defined between the flow pipe and the housing. At least one movable flap is located in the space and is resiliently biased to a closed position and movable by exhaust gas pressure from said closed position to an opened position. The at least one flap provides less restriction to exhaust gas flow through the space in the opened position as compared to the closed position. The one or more flaps are pivotably supported on a spring-biased hinge assembly or are provided as part of a resiliently deformable baffle plate that uncovers flow apertures under force of exhaust pressure. The baffle plate is selectively removable by an end-user to allow for maximum exhaust flow when desired. The flow pipe can be omitted in a base plate only version.
This application claims priority from and benefit of the filing date of U.S. provisional application Ser. No. 60/724,460 filed Oct. 7, 2005, and said provisional application is hereby incorporated by reference into the present specification.
BACKGROUNDSilencers for automobile exhaust systems are known. One type of silencer is known as an active silencer due to its capacity to adjust in response to pressure of exhaust gases in the system. As such, at low engine revolutions per minute (RPM) with correspondingly low exhaust pressure, the silencer remains substantially closed to increase exhaust backpressure and reduce noise, while increase in engine RPM causes a corresponding increase in exhaust gas pressure which, in turn, is used to open the silencer against the closing force of a biasing spring to reduce backpressure which causes an increase in exhaust noise and engine power. While known active silencers are superior to passive silencers, which merely restrict exhaust flow by constant amount, known active silencers have also been deemed deficient for complexity, cost, insufficient backpressure reduction when opened, reliability and other reasons. As such, a need has been identified for a new and improved active exhaust silencer.
SUMMARYIn accordance with one aspect of the present invention, an exhaust silencer includes a housing and a flow pipe supported in the housing. A space defined between the flow pipe and the housing. At least one movable flap is located in the space and is resiliently biased to a closed position and movable by exhaust gas pressure from the closed position to an opened position. The flap provides less restriction to exhaust gas flow through the space in the opened position as compared to the closed position.
In accordance with another aspect of the present invention, and exhaust silencer includes a housing and a base plate secured in the housing. The base plate defines at least one main flow opening and at least one secondary flow opening. At least one flexible metal baffle is secured to the base plate and is normally resiliently biased to a closed position where it covers the secondary flow aperture. The baffle is resiliently movable by exhaust gas pressure from its closed position to an opened position where it moves away from the secondary flow opening(s) to allow exhaust gas flow therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
As illustrated herein, the silencer ES is intended to be retro-fitted into an existing exhaust tailpipe T using one or more fasteners F1 such as a bolt, rivet, screw, etc., or by other means such as welding, friction-fit or the like to secure the silencer to the tailpipe T. In particular, the exhaust silencer ES comprises an outer housing tube H that is fitted into the tailpipe T, and the fasteners F1 or other means are used to fixedly secure the housing tube H relative to the tailpipe T. If necessary and/or desired, a spacer or gasket K can be used to surround the housing tube H to fill any space defined between the tailpipe T and housing tube H. In some cases, such as when the silencer ES is supplied as original equipment, the tailpipe T, itself, provides the housing tube H, and the fasteners F1 are not needed.
At least one open flow pipe P is located, preferably concentrically, in the housing tube H and secured therein by rivets, bolts, screws and/or other fasteners F2 (
An annular space B is defined between the pipe P and the housing H. First and second flow-control flaps C1,C2 are located in the annular space B, near an outer end thereof. These flaps C1,C2 move between a closed position (
As is easily seen in
When the exhaust gas pressure in the annular space B subsides, the springs N1,N2 return the flaps C1,C2 toward and/or fully to their closed positions. Stops M1,M2 are provided and engage the flaps C1,C2, respectively, when the flaps are closed to prevent movement of the flaps C1,C2 beyond their closed positions under force of springs N1,N2. As shown, the stops M1,M2 are defined by indented portions of the housing tube H, but can be defined by rivets, tabs, screws or other suitable fixed member that extends into the annular space B.
Those of ordinary skill in the art will recognize that when the flaps C1,C2 are closed, exhaust gas flow and noise are restricted owing to the fact that the only path for the exhaust gases to flow to the tailpipe outlet O is via pipe P (except for any leakage around flaps C1,C2). When the flaps C1,C2 open under exhaust pressure, the exhaust gas flow and engine performance and noise increase, because the exhaust gases are able to flow to the tailpipe outlet O through the pipe P and also through the annular space B. As such, the exhaust silencer ES provides a self-adjusting capability that is responsive to exhaust gas pressure that varies with driving habits or other causes of variations in exhaust gas pressure.
Except for the optional gasket K, the components of the exhaust silencer are preferably defined from a metal such as steel or stainless steel using grades and alloys that are known in the exhaust arts. The springs N1,N2 are preferably metal and defined from suitable spring wire such as (by way of example only) stainless steel, Inconel, or other metal with sufficient resistance to elevated temperature creep and fatigue.
The silencer ES′ is intended to be retro-fitted into an existing exhaust tailpipe T′ using one or more fasteners F1′ such as a bolt, rivet, screw, etc., or by other means such as welding, friction-fit or the like that engage the tailpipe T′ and housing tube H′. In particular, the exhaust silencer ES′ comprises an outer housing tube H′ that is fitted into the tailpipe T′, and the fasteners F1′ or other means are used to fixedly secure the housing tube H′ relative to the tailpipe T′. If necessary and/or desired, a gasket K′ can be used to surround the housing tube H′ to fill any space defined between the tailpipe T′ and housing tube H′. In some cases, such as when the silencer ES′ is supplied as original equipment, the tailpipe T′, itself, provides the housing tube H′, and the fasteners F1′ are not needed.
At least one open flow pipe P′ is located, preferably concentrically, in the housing tube H′. The pipe P′ is secured in this position by one or more rivets, bolts, screws and/or other fasteners F2′ that engage the housing tube H′ and open flow pipe P′. This open flow pipe P′ has an open upstream end P1′ and an open downstream end P2′ so as to allow free-flow of exhaust gases therethrough from an upstream position in the tailpipe T′ toward the outlet O′ of the tailpipe T′ as indicated by arrow A1′. An annular space B′ is defined between the flow pipe P′ and the housing tube H′.
A baffle base plate D′ is closely fitted in the housing tube H′ and is secured in this position. As shown, the baffle base plate D′ includes an outer flange DF′ that is engaged by the fasteners F1′ or welding or the like to secure the baffle base plate D′ in its operative position in the housing tube H′. The baffle base plate D′ also defines a central pipe-support aperture DA′ through which the open flow pipe P′ extends. An optional fastener F3′ or a spot weld, or other means is used to secure the pipe P′ to the baffle base plate D′. The baffle base plate D′ defines one or more flow apertures DE′ that provide a path for exhaust gases to flow from an upstream location in the tailpipe T′, through the annular space B′ and through the base plate D′ to the tailpipe outlet O′.
To regulate the flow of exhaust gases through the flow apertures DE′ of the base plate D′, at least one flexible baffle J′ is secured adjacent the downstream side of the base plate D′(facing tailpipe outlet O′). The baffle J′ is preferably defined by a flexible metal sheet that includes an opening JO′ through which the flow pipe P′ is loosely received. As shown, the baffle J′ is secured directly to the base plate D′ by one or more rivets, screws or other fasteners F4′. In some cases, the fasteners F4′ are preferably non-removable and in others, the fasteners F4′ are screws or other removable fasteners that allow a user to change baffles J′ or add (by stacking) additional baffles J′ to control exhaust flow. As is shown in
The baffle J′ is selected so that it bends to the opened position to allow exhaust gas flow through the flow apertures DE′ when the exhaust gas pressure in the annular space B exceeds a select threshold, which will vary depending upon the desired performance characteristics and the particular vehicle or other application. In one embodiment, the baffle J′ is intended to stay closed during idle of an automobile, to open slightly and partially uncover the apertures DE′ during normal vehicle acceleration, and to open fully during hard acceleration to at least substantially uncover the apertures DE′. When the exhaust pressure in the annular space B′ subsides, the baffle J′ resiliently returns to its normally closed position, which is a relatively flattened (not necessarily completely flat) state relative to the opened position.
Those of ordinary skill in the art will recognize that when the baffle J′ is closed, exhaust gas flow and noise are restricted owing to the fact that the only path for the exhaust gases to flow to the tailpipe outlet O′ is via open pipe P′ (except for some leakage around the baffle base plate D′ and/or leakage through flow apertures DE′). When the baffle J′ opens, the exhaust gas flow and engine performance and noise increase, because the exhaust gases are able to flow to the tailpipe outlet O′ through both the pipe P′ and also through the annular space B′ via apertures DE′. As such, the exhaust silencer ES′ provides a self-adjusting capability that is responsive to exhaust gas pressure that varies with driving habits or other causes of variations in exhaust gas pressure.
Except for the optional gasket K, which can be a heat/fire resistant insulation material, components of the exhaust silencer ES′ are preferably defined from a metal such as steel or stainless steel using grades and alloys that are known in the exhaust arts. The baffle J′ is preferably defined from metal such as (by way of example only) stainless steel, Inconel, or other metal with sufficient resistance to elevated temperature creep and fatigue, having a thickness, e.g., in the range of 0.005 inches to 0.015 inches (the thickness is varied to control the exhaust pressure required to flex the baffle J′ to its opened position). If desired, the user can selectively remove the baffle ′ to allow full exhaust flow under all conditions by removing screws F4′. Also, the baffle J′ can be changed by a user to control the opening pressure (by replacing a baffle J′ with another having different flexibility), and multiple baffles J′ (of same or varied thickness/flexibility) can be stacked against the base plate D′ if desired to increase the pressure required to open the flow apertures DF′.
In another alternative embodiment 3ES′ as shown in
While considerable emphasis has been placed on the preferred embodiments, it will be appreciated that other embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention, and it is intended that the following claims be construed literally and/or according to the doctrine of equivalents as broadly as possible.
Claims
1. An exhaust silencer comprising:
- a housing;
- a flow pipe supported in said housing;
- a space defined between said flow pipe and said housing;
- at least one movable flap located in said space and resiliently biased to a closed position and movable by exhaust gas pressure from said closed position to an opened position, wherein said at least one flap provides less restriction to exhaust gas flow through said space in said opened position as compared to said closed position.
2. The exhaust silencer as set forth in claim 1, wherein said at least one flap pivots between said closed and opened positions.
3. The exhaust silencer as set forth in claim 2, wherein said at least one flap comprises first and second separate flaps that each pivot between said closed and opened positions.
4. The exhaust silencer as set forth in claim 3, further comprising at least one spring engaged with said first and second flaps to bias said first and second flaps to their respective closed positions.
5. The exhaust silencer as set forth in claim 4, further comprising first and second hinges that extend between said flow pipe and said housing, wherein said first and second flaps are each connected to both said first and second hinges, and wherein said at least one spring is a torsion spring connected to one of said first and second hinges.
6. The exhaust silencer as set forth in claim 5, wherein said at least one spring comprises first and second springs respectively connected to said first and second hinges, wherein each of said first and second springs is engaged with both of said first and second flaps.
7. The exhaust silencer as set forth in claim 6, further comprising first and second stops located between said housing and said flow pipe, said first and second stops abutting said first and second flaps, respectively, when said first and second flaps are in their respective closed positions.
8. The exhaust silencer as set forth in claim 7, wherein said first and second flaps define a 180 degree angle therebetween when the first and second flaps moved to their closed positions, and wherein said first and second flaps define therebetween an angle of less than 180 degrees when the first and second flaps are moved their respective opened positions.
9. The exhaust silencer as set forth in claim 7, wherein said flow pipe is located centrally in said housing so that said space defined between said housing and said flow pipe is an annular space that encircles said flow pipe.
10. The exhaust silencer as set forth in claim 9, wherein said first and second hinges are arranged in diametrically opposed locations relative to each other.
11. The exhaust silencer as set forth in claim 10, wherein said flow pipe defines an unobstructed flow path from an open upstream end to an open downstream end thereof.
12. The exhaust silencer as set forth in claim 1, wherein said at least one flap is defined as part of a flexible metal baffle that is secured in said space, wherein said at least one flap moves from said closed position to said opened position by resilient deformation of said metal baffle under force of exhaust gas pressure in said space, and wherein said at least one flap resiliently moves from said opened position to said closed position when said exhaust gas pressure in said space subsides.
13. The exhaust silencer as set forth in claim 12, wherein said at least one flap comprises first and second flaps.
14. The exhaust silencer as set forth in claim 13, wherein said first and second flaps are defined by said metal baffle as a one-piece construction.
15. The exhaust silencer as set forth in claim 12, further comprising a base plate secured in said space between said flow pipe and said housing, said base plate defining at least one flow aperture, wherein said metal baffle is secured to said base plate and occludes said at least one flow aperture when in said closed position and moves away from said at least one flow aperture when in said opened position.
16. The exhaust silencer as set forth in claim 15, wherein said metal baffle is secured to said base plate by at least one removable fastener that allow for selective separation of said baffle from said base plate for maximum exhaust flow.
17. The exhaust silencer as set forth in claim 16, wherein said base plate comprises an outer flange that is secured to said housing and comprises a pipe support aperture through which said flow pipe extends, and wherein said baffle comprises an opening through which said flow pipe extends.
18. The exhaust silencer as set forth in claim 12, wherein said metal baffle comprises a flexible metal sheet.
19. The exhaust silencer as set forth in claim 1, wherein said at least one flap is defined by a stack of at least two flexible metal baffles that are secured in said space, wherein said at least one flap moves from said closed position to said opened position by resilient deformation of said stack of metal baffles under force of exhaust gas pressure in said space, and wherein said at least one flap resiliently moves from said opened position to said closed position by relative flattening of said stack of metal baffles when said exhaust gas pressure in said space subsides.
20. The exhaust silencer as set forth in claim 20, further comprising a base plate secured in said space between said flow pipe and said housing, said base plate defining at least one flow aperture, wherein said stack of metal baffles is secured to said base plate and occludes said at least one flow aperture when in said closed position and moves away from said at least one flow aperture when in said opened position.
21. An exhaust silencer comprising:
- a housing;
- a base plate secured in the housing, the base plate comprising at least one main flow opening and at least one secondary flow opening;
- at least one flexible metal baffle secured to the base plate and normally resiliently biased to a closed position where it covers the secondary flow aperture, wherein said baffle is resiliently movable by exhaust gas pressure from said closed position to an opened position where it moves away from the at least one secondary flow opening to allow exhaust gas flow through the at least one secondary flow opening.
Type: Application
Filed: Oct 6, 2006
Publication Date: May 17, 2007
Inventor: Jason Sicotte (Bristol, CT)
Application Number: 11/544,201
International Classification: F01N 1/16 (20060101);