Variable sound muffler system   

The invention relates to a muffler system for use in a vehicle such as a motorcycle, automobile, truck, boat or recreational vehicle. The muffler system includes a remote switch that enables a user to control the exhaust sound.

Exhaust systems are used on vehicles to draw off exhaust gases formed as a result of engine operation. Exhaust mufflers may be used for the silencing of exhaust noises. Generally the muffler will include some form of a duct that allows for the passage of gas and sound through it. The duct will also include a series of holes along its surface and is surrounded by a noise-dampening/sound-absorbing material. As the exhaust gas and sound passes through the duct some of the sound passes through the series of holes and is absorbed by the noise-dampening/sound-absorbing material.

The exhaust system for an internal combustion engine is designed to perform many functions. One of the primary functions of the exhaust system is to convey hot exhaust gases away from the engine and discharge the exhaust gases to the atmosphere at a location and in a direction away from the operator of the engine. In the case of motorcycles, cars, trucks, boats and recreational vehicles, the exhaust gases are preferably discharged from the rear of the vehicle to minimize driver and passenger exposure to the exhaust gases. Another important function of the exhaust system is to silence or muffle hazardous and objectionable noises.

The present invention provides a muffler system, or part of a system, for use on a vehicle, that allows a user to vary the exhaust sound, note or pitch using a remote switch or device.

The present invention provides a muffler system that includes two pipes, one pipe located inside the other. Both pipes are perforated with corresponding apertures, e.g. holes or slots, for sound absorption. As the outer pipe is turned by an electric motor or mechanical device, the holes or slots may be partially or completely aligned and sound changing qualities are produced. This enables the operator to change the exhaust note from quiet to loud using a switch connected to the motor or device and mounted, for example, inside the vehicle or recreational vehicle cockpit or on the handlebars of a motorcycle or recreational vehicle.

The present invention provides a muffler system having a housing, a first pipe located within the housing and a second pipe rotatably mounted on the first pipe. The first and second pipes each having a plurality of complementary apertures. The system also has an actuating means connected to at least one of the first pipe and/or the second pipe for rotating one of the first or second pipes relative to the other.

The present invention provides a muffler system having a housing, a first pipe located within the housing and a second pipe either rotatably mounted on the first pipe or mounted on the second pipe and adapted to move longitudinally relative to the first pipe. The first and second pipes each having at least one aperture. The system also has an actuating means connected to at least one of the first pipe and/or the second pipe for rotating one of the first or second pipes relative to the other.

The present invention further provides a muffler system having a housing, a first pipe located within the housing and a second pipe mounted thereon and adapted to move longitudinally relative to the first pipe. The first and second pipes each having a plurality of complementary apertures located therethrough. The system also includes an actuating means connected to the second pipe for moving the second pipe in a longitudinal direction relative to the first pipe.

The present invention further provides a muffler system having a housing, an exhaust conduit and a conduit cover. The exhaust conduit is operable for the passage of exhaust gas having a plurality of first apertures therethrough and the conduit cover is connected to the conduit and includes a plurality of second apertures. The cover is operable to cover the plurality of first apertures located on the exhaust conduit and is adapted to move relative to the exhaust conduit to partially or completely align the plurality of second apertures with the plurality of first apertures. The system also includes an actuating means connected to the conduit cover that is operable to move the cover relative to the conduit.

The present invention further provides an insert for use with a straight-through muffler system, comprising a first pipe and a second pipe mounted on the first pipe, the first and second pipes each comprising at least one aperture therethrough, the pipes being sized to be received within the straight-through muffler, at least one connection means attached to at least one of the first or second pipes and operable to releasably attach the insert to the straight-through muffler and at least one positioning means located on the peripheral end of the first pipe and operable to indicate to a user the position of the second pipe relative to the first pipe. The second pipe may be rotatably mounted on the first pipe or may be mounted on the first pipe and operable to move longitudinally relative to the first pipe.

The present invention will now be described in further detail with reference to the following figures:

FIG. 1 is a longitudinal cross sectional view of one embodiment of the muffler system of the present invention showing the first and second pipes in a position with the apertures located in each pipe in complete alignment;

FIG. 2A is an axial cross sectional view of the muffler system of FIG. 1;

FIG. 2B is a perspective cross section of a portion of FIG. 3A illustrating the direction of rotation of the second pipe relative to the first pipe;

FIG. 3 is a side view of the first and second pipes of the muffler system of FIG. 1 with a partial cut away of the second pipe;

FIG. 4 is a longitudinal partial cross section of the system of FIG. 1 with a partial alignment of the apertures of the pipes;

FIG. 5 is a longitudinal partial cross section of an alternative embodiment of the muffler system of the present invention illustrating a longitudinal movement of the second pipe relative to the first;

FIG. 6 is a partial view of the pipes of FIG. 5 illustrating a partial overlap of the apertures of the pipes relative to each other;

FIG. 7A to 7D are a series of partial views of the first and second pipes of the present invention illustrating some of the possible variations in the alignment of the apertures of the second pipe relative to the first;

FIG. 8 illustrates examples of some of the shapes that may be used for the apertures of the first and second pipes;

FIG. 9 illustrates the muffler system of the present invention connected to inlet and outlet pipes clearly having a smaller diameter than the first and second pipes of the muffler system;

FIG. 10 illustrates a sound deadening insert for use in the present invention;

FIG. 11 illustrates a further embodiment which provides an exhaust insert according to the present invention for use with a straight-through muffler;

FIG. 12a is a cross sectional side view of the exhaust insert of FIG. 11 placed in a straight-through muffler;

FIG. 12b is an end view of the insert of FIG. 12a taken along line 12b-12b;

FIG. 13 is a perspective view of the inside portion of the first pipe of the muffler system according to the present invention including a butterfly valve; and

FIG. 14 is a photograph of the end of the first and second pipe showing the first pipe located within the second pipe and showing the end plates of both pipes.

The present invention provides a system that allows for muffler or exhaust sound to be changed from quiet to loud in varying stages. The muffler system can be applied to vehicles such as, but not limited to, motorcycles, cars, trucks, boats, recreational vehicles and any fuel systems that use exhaust means or any engine from which exhaust sounds are produced and can be regulated.

The present invention provides a muffler system, for use on a vehicle or fuel system having an exhaust, that allows the user of the vehicle or fuel system to vary the sound emitted from the system.

In one embodiment, the muffler system includes a conventional muffler housing that has been internally adapted to variably adjust the exhaust sound note, remotely by the user, and is attached or installed to the exhaust pipe of a vehicle operating a conventional gas, propane, diesel, hybrid, combination (i.e. electric and fuel, hydrogen, etc.) fuel system engine the typical way all mufflers are installed. In addition the system includes a remotely installed user switch to allow the user to vary the sound level characteristics.

Within the housing there is located a first pipe that is adapted for connection to the exhaust pipe of the vehicle/fuel system engine. The first pipe is operable to allow the passage of exhaust gas and sound therethrough. The first pipe has a plurality of apertures located throughout. A second pipe is located within the housing and is connected to and surrounds the first pipe. The second pipe also includes a plurality of complementary apertures that when aligned with the apertures of the first pipe will provide an opening for the exhaust gas and sound within the first pipe to pass through but when not aligned the non-aperture portion of the second pipe will block the apertures of the first pipe and will no longer allow the gas and sound to pass through and therefore forcing the exhaust gas and sound out of the exhaust end of the first pipe. The chamber may also contain parabolic or conical diverters or re-routing devices, including but not limited to baffles, doors, bumps, concave surfaces or protrusions to enhance, adjust, re-direct or generally assist, modify or change the sound management qualities or gas flow directions.

Surrounding the first and second pipe is located noise-dampening/sound-absorbing material that is gas permeable, for example, high temperature acoustical absorbing material, high temperature resistance inert packing such as fibreglass baht, steel wool, sound deadening composite or sound-deadening packing material such as fibrous metal, glass, polyarimides; glass or ceramic open cell foams; ceramic wool or felt; multiple layers of fine screening, stainless steel, ceramic fibres, metallic fibre, fibrous material, glass fibre, polyarimides fibrous materials, metal fragments, single strand fibreglass acoustic fill material, or precious metals that will absorb any sound that passes through the apertures of the first and second pipe when partially or fully aligned. It will be understood by a person skilled in the art that combinations of these and/or other sound absorbing materials may also be used.

The movement of the first and second pipes relative to each other is controlled by an actuating means which may be a motor or servo switch. The control of the actuating means is activated by a switch. The switch allows a user to control movement of the pipes and thereby the alignment of the apertures which controls the volume of sound that passes through into the sound absorbing material.

The present invention will now be described in detail with reference to the accompanying Figures. One embodiment of the muffler system of the present invention is shown in FIG. 1. The muffler system 10 comprises a housing 12 containing a first pipe 14, having a plurality of first apertures 16 (not shown) therethrough, located within a second pipe 18, having a plurality of second apertures 20 therethrough. Surrounding the pipes 14, 18 within the housing 12 is sound absorbing material 22. Connected to the housing 12 is a motor 24, for example a 12 volt servo motor, that is connected to a remote switch 26, shown in FIG. 4. The motor 24 controls the movement of the pipes 14, 18 relative to one another and is operated by the switch 26 controlled by and optionally located adjacent a user of the vehicle to which the muffler system 10 is attached.

The sound absorbing material 22 fills the housing 12 in a similar manner as a conventional muffler system. As such, the material is wrapped around the perforated pipes 14, 18 in a calculated method, i.e. computer designed or engineered, for example in a wafer or laminate style with different materials of different thicknesses layered upon each other to offer the maximum potential of sound deadening qualities to the system when the pipe is in full quiet mode. These layers, sandwiches, wafers, laminates and mixtures of materials will be determined for the application individually and specifically for each vehicle, by a person skilled in the art. Methods for determining such are well known in the art.

In addition, a thin layer of material such as a honeycomb wafer may optionally be placed between the pipes, 14, 18 in some applications. This may offer rattle proof features to a system or an alignment configuration for exhaust sound to travel through.

The types of pipes 14, 18 used in the present invention are known in the art and may be made from, but are not limited to, steel, aluminum, stainless, titanium, carbon fibre, platinum and/or other precious metals. The pipes may also be made from high heat plastics.

As can be seen from the Figures, most particularly FIG. 9, the pipes 14, 18 preferably have a larger diameter than the inlet and outlet pipes 38, 40. The first pipe 14 may be designed so that the diameter of the pipe increases from the housing edge at the connection to the inlet pipe 38. This change in diameter slows the pulses of the exhaust gas down and allows more sound to be absorbed. As an example, the inlet pipe 38 from the engine may be 2.25″ on the internal diameter and the first pipe 14 may be approximately 2.5″ or larger.

The housing 12 is operable to be connected to an exhaust outlet 38 of an engine in which the muffler system 10 is to be used. The housing 12 may be made from material known and used in the art, such as stainless steel or aluminized steel exhaust canisters made from 16 or 18 gauge or thinner. The housing 12 is connected to the exhaust outlet to allow for the flow of exhaust gas and sound from the exhaust outlet into the first pipe 14 located in the muffler system 10. The direction of the flow of the exhaust gas and sound is indicated at arrow A in FIG. 1 showing the entry into the first pipe 14 and at arrow B showing the exit from the first pipe 14.

Turning to FIGS. 2A, 2B and 3 the interaction of first pipe 14 and the second pipe 18 will be discussed in further detail. In this embodiment the first pipe 14 is located within the second pipe 18 and includes a plurality of first apertures 16 that may be aligned with a plurality of second apertures 20 in the second pipe 18. As indicated at arrow C in FIG. 2A and arrow D in FIG. 2B, the second pipe 18 is rotatably mounted on the first pipe 14. Rotation of the second pipe 18 will allow a user to align the second apertures 20 with the first apertures 16 on the first pipe 14. The degree of rotation of the second pipe 18 will provide varying levels of overlapping of the apertures, including complete overlap and no overlap.

The second pipe 18 may be free to rotate freely about first pipe 14 or may be limited in its rotational movement. The rotation of the second pipe 18 around the first pipe 14 may be limited by the placement of a screw or stopper (not shown) at a fixed point. Such a limitation may be used for an application where control over the maximum noise output is required. For example, a vehicle noise restriction limitation enforced by a law or a workplace noise limitation. The limitation of rotation of the pipes may be included at the time of installation or may be retrofitted after the system is installed. In addition, the limiting stopper or screw may be tamper-proof or may be adjustable to allow a user to remove it when required.

The first pipe 14 is connected to the housing 12 by conventional means which are known by a person skilled in the art. The second pipe 18, is connected to the first pipe 14 to allow for movement about the first pipe 14 in a rotational manner. The second pipe 18 is attached to the first pipe 14 in a manner that maintains the relative placement of the pipes 14, 18 to allow for the alignment of the apertures. For example, the pipes 14, 18 may be connected using a set of ridges and grooves or stoppers or bearings.

The rotation of the second pipe 18 about the first pipe 14 allows for partial or complete alignment of the plurality of first and second apertures 16, 20. Alternatively the second pipe may be rotated in order that the plurality of first apertures 16 are blocked, or closed, by the second pipe 18. Examples of some of the varying degrees of overlap of the apertures are illustrated in FIGS. 7A-D. However, it will be understood that these examples are not limiting in any way.

As can be seen more clearly in FIG. 2A, the rotation of the second pipe 18 relative to the first pipe 14 is controlled by an actuating means, also referred to herein as a motor 24. The motor 24, in this embodiment, includes a series of teeth 28 that interlock with complementary grooves 30 on the exterior of the second pipe 18. As the motor 24 runs it rotates about an axis, causing the interlocking teeth 28 and grooves 30 to rotate the second pipe 18 simultaneously. The degree of rotation can be controlled by the switch 26 that is connected to the motor 24. Other examples of connecting the motor to the second pipe include, but are not limited to, gear tooth in slot, sprocket in slot, chain operated or gear reduction methods. It will be understood that the mechanism, such as teeth and grooves, for moving the pipes may be integral with the motor 24 or may be a separate component that is connected to the motor.

It will be understood by a person skilled in the art that the motor may be connected to the first pipe 14 and that the first pipe 14 may be rotated relative to the second pipe 18. Alternatively, the motor may be connected to both pipes and may rotate both pipes simultaneously relative to each other.

The apertures 16, 20 of the embodiment of FIGS. 1-4 are shown as a series of parallel lines of evenly spaced apertures. FIG. 2B illustrates the position of the second pipe 18 relative to the first pipe 14 when the second pipe 18 blocks the first apertures 16 of the first pipe 14. In contrast, FIG. 3 illustrates the position of the second pipe 18 relative to the first pipe 14 when the apertures 16, 20 are aligned. FIG. 4 illustrates a position of the second pipe 18 relative to the first pipe 14 in which the second apertures 20 substantially overlap with the first apertures 16. The location and shapes of the apertures will be discussed in further detail below.

Turning to FIGS. 5 and 6 a second embodiment of the invention will now be described. In this embodiment the movement of pipes 14, 18 relative to each other is a longitudinal movement indicated by arrows E and F in FIGS. 5 and 6, respectively. The control of the movement of the pipes 14, 18 relative to each other in a longitudinal direction is controlled by motor 24. The movement of the second pipe 18 relative to the first pipe 14 may be controlled by a piston type connector attached to the second pipe 18 and the motor 24. The movement may be smooth or may comprise a step like movement between several different longitudinal positions. The connection between the second pipe 18 and motor 24 (not shown) may be a piston or ratchet-type mechanism. The second pipe 18 may move any amount of distance in the longitudinal direction that allows for partial and complete alignment of the apertures. As an example, the second pipe 18 may be operable to move about 1″ or more in the longitudinal direction. It will be understood that the required amount of movement will depend on the shape and configuration of the apertures.

As mentioned above, the pipes 14, 18 can be moved relative to each other in order to achieve varying degrees of alignment of first and second apertures 16, 20. FIGS. 7A-D illustrate a series of possible alignment positions. These illustrated positions are not meant to be limiting, it will be understood that any degree of alignment is possible between the closed position or no alignment shown in FIG. 7A and the open or full alignment shown in FIG. 7C.

FIGS. 1 through 7 illustrate the first and second apertures 16, 20 as a series of aligned round holes. However, the apertures located in first and second pipes may take any shape provided that the positioning of first and second pipes 14, 18 allow for a position in which the apertures 16, 20 are fully aligned and a position in which the apertures 16 located on first pipe 14 are completely blocked by second pipe 18. Examples of different shapes that may be used for apertures 16, 20 are illustrated in FIG. 8. These examples are not intended to be limiting in any way and include circles, squares, triangles, slots, moons, crosshatch, convoluted shapes, convex rises, bars, mesh, computer generated patterns to apply to performance and sound dampening qualities. The apertures may only comprise a single aperture located on each pipe that is of sufficient width and length to accomplish the aim of the present invention, for example the aperture may be an “s” shaped aperture that stretches the length of each pipe. Sizes may vary from a pin hole through to larger sizes in the 0.05 to 0.50 to 0.99 to 1.5 ranges and so forth. Sizes may be determined via computers programs, dyno testing and other methods to develop the ultimate in sound deadening qualities for the muffler system when in full quiet mode, and vice-versa in full volume mode.

The muffler system 10 of the present invention may be placed on a new vehicle or alternatively the internal components of the muffler system 10 may be retrofitted into an existing exhaust system. It will be understood by a person skilled in the art that the size of the muffler system 10, including the housing 12 and pipes 14, 18, may vary in size with respect to the end use intended. The dotted line 36 in FIG. 2A and FIG. 9 indicates one possible variation in the size of the muffler system housing. For example, it will be understood by a person skilled in the art that a muffler system used on a motorcycle may be more compact than one used on a truck.

When the muffler system 10 of the present invention is attached to a vehicle the switch 26 that is connected to motor 24 is preferably located adjacent the user of the vehicle and remote from the placement of the housing 12. This allows the user to easily manipulate the positioning of the first and second pipes 14, 18 relative to each other and thereby control the sound emitted from the muffler system without having to manually manipulate the housing 10. The switch may be connected to the motor 24 using technology known in the art, such as space or aircraft type technology with braided conduit or an analog switch. The braided or protected conduit may be routed from the muffler via wires through the frame or outside the frame of a car or truck to the control area of the vehicle, i.e. the handlebars or cockpit/dash. It will be understood that the term “switch” is used to describe a mechanism that allows a user to control the actuating means/motor and is not limited to being a mechanical switch but also includes control mechanisms known generally in the art including, but not limited to, buttons and knobs.

The housing 12, first and second pipes 14, 18 and the sound absorbing material 22 are components that are frequently used in known muffler systems. It will be understood from the description of the embodiments above that the second pipe 18 will be sized to contain the first pipe 14 within it. The pipes 14, 18 of the invention are manufactured for a close fit, i.e. close tolerance. Optionally, a mat or Teflon film or other honeycomb like material may be placed between the pipes in order to obtain a close fit. It will be understood by a person skilled in the art that any material placed between the pipes 14, 18 should either also include apertures that are aligned with those of the first and second pipes 14, 18 or should be made from a material that will not substantially hinder the passage of sound therethrough in particularly when the apertures of the first and second pipes are aligned.

In a further embodiment of the present invention the first pipe 14 may only include apertures along a portion of the surface and the second pipe 18 may only be a partial pipe or a sheet of material sized to correspond to the portion of the first pipe 14 that includes the apertures. In this embodiment it will be understood that the second partial pipe or piece of material will also include apertures that correspond to those on the first pipe and will be connected to the first pipe so that the aperture on the first pipe may be aligned with those on the partial pipe or be covered by the partial pipe. The connection of the partial pipe and movement about the first pipe is as described above.

In a further embodiment, illustrated in FIG. 10, the present invention further provides a sound deadening insert 110 which may be used in combination with any of the embodiments described herein. The sound deadening insert 110 has a cross sectional accordion shape, as can be seen in FIG. 10a, and is sized to be received within a muffler adjacent the inside surface. The sound deadening insert 110 may be used for additional sound absorption. As can be seen in FIG. 10a the sound deadening insert 110 includes a plurality of apertures 116 on each folded surface. The configuration of the apertures 116 and the folded accordion style of the insert 110 limits bounce back of sound waves and absorbs more sound providing a quieter volume from the muffler. It will be understood that the number and configuration of apertures is not limited to the embodiment shown and may be changed according to the requirements of the user. In addition, the number of accordion folds in the insert may be varied in order to achieve the sufficient amount of sound absorption required.

In an alternative embodiment of the present invention, an exhaust insert 210 is provided to be used a straight-through muffler. The insert 210 is shown in FIGS. 11 and 12a,b. The insert 210 is inserted into a straight-through muffler, in the direction indicated by arrow A in FIG. 11, and held in position by one or more allen screw attachments 230. In the illustrated embodiment three allen screw attachments 230 are shown however, it will be understood that any number may be used provided they secure the insert 210 to the muffler. Further, any type of attachment mechanism may be used provided it is removable and will hold the insert 210 securely in place during use. The insert 210 may be configured manually prior to insertion into the muffler to allow for variation in the volume of the muffler. Alternatively, the insert may be adjusted when already positioned in the muffler, when the vehicle is not operational.

The insert 210 comprises a first and second pipe 214, 218, clearly shown in FIG. 12b as discussed above. The second pipe 218 is rotatably mounted on the first pipe 214 and is operable to rotate about the first pipe 214. In the illustrated embodiment, the pipes include a first outer portion 234 and a second inner portion 236. Both pipes includes a plurality of apertures 216 located on the second inner portion 236 that are sized and shaped so that when the first and second pipes 214, 218 are aligned the apertures are operable to completely overlap. It will be understood that the first pipe may include apertures over all of its surface and the second pipe only include apertures on the second inner portion 236. Alternatively both pipes may includes apertures over their surface. The illustrated embodiment is not meant to be limiting but serves as an example of one embodiment of the invention. The configuration and operation of the rotating pipes and alignment of the apertures has been discussed in detail above. Likewise, the second pipe may be attached to the first pipe and be operable to move longitudinally along the first pipe, as described above.

The second inner portion 236 of the pipes is sized to be received within a straight-through muffler, as shown in FIG. 12a. When the insert 210 is placed within the muffler, the inner portions 236 of the first and second pipes 214, 218 are received within the main body, indicated at numeral 238, of the muffler while the outer portions 234 are received within the end, indicated at numeral 240, of the muffler.

At the outer end of the first outer portion 234 of the second pipe 218 extend two connection arms 242. Each arm 242 extends outwardly from the surface of the outer portion 234 and then extends parallel to the body of the insert 210 along a portion of the length of the first outer portion 234. At the end of each arm 242 is an attachment means 234 that releasably attaches the insert 210 to the end 240 of the muffler. In the embodiment illustrated the attachment means comprises three allen screws that are operable to releasably engage with the end 240 of the muffler. When the insert 210 is placed within the muffler the allen screws are tightened to abut the outside end 240 of the muffler to secure it in place. When removal of the insert 210 is required, the allen screws are loosened so that the insert 210 may be removed. As discussed above, any type of attachment means, for examples, screws, bolts etc., may be used to releasably secure the insert 210 in place. In addition, the insert 210 may be connected directly to the muffler pipe using an attachment means, such as a screw or bolt, without the use of the arms illustrated in FIGS. 11 and 12a. It will be understood that the attachment of the insert 210 to the muffler pipe should allow for secure attachment during use but also allow a user to remove the insert 210 when and if desired.

In the illustrated embodiment, located on the end of the insert 210 is positioning plate 244, also referred to as an end plate, which also serves as a sound selector. Positioning plate 244 is located around the periphery of the opening of the insert 210 and is sized to include positioning indicators 246. The positioning indicators 246 indicate to a user the position of the first pipe 214 relative to the second pipe 218. In the illustrated embodiment, each of the first and second pipes include end plates or positioning plates 244, as can be seen in FIG. 14, the positioning plates 244 include positioning indicators 246 which serve to position the first and second pipes relative to each other and comprise a series of setting holes that are manually screwed into each of the end plates/positioning plates to secure the first and second pipes 214, 218 in pre-selected positions. The setting holes are fixed into place using screws. The insert 210 also includes indicating means 248 to indicate to a user which setting provides more or less volume. For example, and as indicated, the indicating means 248 may include a series of “+” and symbols that will indicate the volume to the user. The indicating means 248 is located on the outer most positioning plate for viewing by the user. Other indicating means may be used and it will be understood that the illustrated embodiment is purely exemplary and not meant to be limiting in any way. In use, once the insert 210 has been placed and secured in the muffler pipe, the user can remove the screw located in the hole at the positioning indicator 246 and by hand turn the pipes 214, 218 to the next position, indicated by the indicating means 248. Once the insert 210 has been placed in the next position the screw is returned to the slot and the pipes secured in place.

It will be understood that the positioning of the two pipes may be controlled and indicated by other means known in the art, provided that the pipes are operable to move relative to each other and can be secured in place once the desired setting is achieved. The positioning indicators and indicating means may be one and the same and can be other than the illustrated embodiment provided that they indicate to the user the position of the pipes and allow for adjustment of the position to alternative positions depending on the requirements of the user, i.e. the volume of sound desired to be emitted from the muffler.

The insert 210 is preferably provided as a retrofit unit that may be provided in one piece with the first and second pipes 214, 218 connected together and including the adjustment feature described above. The insert 210 is therefore operable to be immediately fitted into a muffler pipe and secured in place by the attachment means. The insert 210 may also be provided in separate pieces and may require assembly before use.

In a further embodiment, illustrated in FIG. 13 the present invention provides a system and/or insert as described above which further includes a butterfly valve, indicated at 300 located within the first pipe 114. The butterfly valve 300 includes a valve guide, or opening means, 302 that passes through the first pipe 114 in a configuration such that the second pipe 118 engages the opening means 302 and causes it to open and/or close.

In the illustrated embodiment, the butterfly valve 300 is actuated by valve opening means 302 that extends from the valve 300 out of a slot 304 located on the first pipe 114. The valve opening means 302 is operable to open and close the butterfly valve 300. In operation when the second pipe 118 is releasably connected to first pipe 114 and is operable to rotate about first pipe 114, during rotation the second pipe 118 engages the valve opening means 302. The butterfly valve 300 is installed within first pipe 114 so that rotation of the second pipe 118 in a direction that aligns the apertures on both pipes will also engage the valve opening means 302 to move it to close the valve 300. When the pipes are rotated so that the apertures 116 are not aligned, i.e. the pipe is closed, the second pipe 118 will engage the valve opening means 302 to move so that the butterfly valve 300 is open. Variations between these two positions is also possible as rotation of the second pipe 118 will move the valve opening means 302 between these positions that will partially open the butterfly valve 300. Arrows A and B indicate the movement of the butterfly valve when opening. Arrows A indicated the folding inward movement of the valve while Arrows B indicate the forward movement. It will be understood that the mechanism of opening and closing of the butterfly valve is well known and understood by a person skilled in the art.

The system may be used to reduce after market exhaust noise for sensitive areas and gives the operator the choice of changing the exhaust sound while in motion or stationary, with the engine running or not, via a remote switch. As noted above, the muffler system may be retrofitted into existing exhaust systems.

The system may be operated manually or electrically via high temperature motor or servo switch. The muffler system may be applied to a dual pipe muffler system but still use only one motor or servo in most applications. The system offers resolution to loud exhausts in sensitive areas, but still offer the option of a loud exhaust when requested by operator. The system may be adjusted to change the exhaust from a baffled sound deadening type system to a straight pipe type system at the flick of a switch. The muffler system may replace any vehicle muffler with bolt on installation. The Variable muffler system may be used in any muffler application, single or dual design, or crossover styles as such in Porsche or Lamborghinis.

The exhaust system of this invention may be provided as a sound management kit having changeable turnability for different engines and/or different performance objectives. Also it may be offered as a retrofit conversion and core samples of stock units will be overhauled with this system thus taking a stock or aftermarket muffler and converting its internal components and/or mechanisms to our variable system. The ability to retrofit a system allows users to keep a stock looking exhaust but with the new variable sound changing ability installed and available at a button switch on the handlebars or a motorcycle or sport recreational vehicle or with a typical auto type switch from inside the car, truck, boat or other type of vehicle. This may also reduce the price of exhaust replacement by taking and compensating for core samples. The system allows a user to ensure that the vehicle conforms to local laws and regulations, where applicable, and at the push of a button change to a louder system in localities were there are differing sound laws or in the countryside where no one may be disturbed by a loud exhaust system. The system also provides the ability to quiet the ride sound for parades, passengers and for riding in close proximity or in groups, so as to not annoy or distract other group riders. However, when necessary have the ability to turn the noise on, if required. For example, a non-motorcycle or larger vehicle may realize that a motorcycle is near them due to the loud and discernable noise being emitted through a pipe on full loud position.

The variable sound exhaust systems may be used with a conventional centrifugal spark arrester or a screen-type spark arrester or may use a conventional certified or non-certified spark arresting device, which is necessary for legal operation in many state or federal lands or by national or provincial fire prevention bylaws.

While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modification of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. Further, all of the claims are hereby incorporated by reference into the description of the preferred embodiments.