Patent Application
20200240299
The present disclosure relates to a sound attenuation system for an internal combustion engine on a machine. More specifically, the present disclosure relates to a multi-chambered sound attenuation system that targets multiple ranges of frequencies.
Internal combustion engines generate engine and exhaust noise due to the combustion of fuel, and due to exhaust gas passing through the engine emission system. Some noise-sensitive locations may require the use of noise attenuation components such as mufflers. Most exhaust muffling systems are configured to muffle lower frequency noise (such as, for example 0-300 Hz). Mid to high frequency noise (such as, for example 300-5000 Hz) may also be emitted by an internal combustion exhaust system due to exhaust gasses traversing the exhaust system. Commercially-available muffler systems may not meet performance requirements for low, mid, and high frequency sound attenuation, while also satisfying other non-performance requirements such as, for example, ease of manufacturability, pressure drop targets, overall costing targets etc.
An example system for sound attenuation is described in U.S. Patent Application No. 2017/0218806 (hereinafter referred to as the '806 reference). In particular, the '806 reference describes a muffler system with three chambers for sound attenuation. The system described in the '806 reference does not, however, target both low, mid, and high frequency noises while attenuating sound 28-35 decibels (dB). Moreover, conventional muffler systems, including the system described in the '806 reference, may not attenuate noise to these noise reduction levels while minimizing manufacturing complexity and cost. For example, the '806 reference describes a muffler design that may be unnecessarily complex, with a high number of unique parts that are not repeated throughout the assembly.
Example embodiments of the present disclosure are directed toward overcoming the deficiencies described above.
In an aspect of the present disclosure, an apparatus for engine exhaust sound attenuation includes a housing having an interior and an exterior, and a plurality of baffle plates arranged within the housing. The plurality of baffle plates may be disposed apart from each other to define an inlet chamber at a proximal end of the housing, an outlet chamber at a distal end of the housing, and a plurality of intermediate chambers disposed between the inlet chamber and the outlet chamber. The plurality of intermediate chambers include a first intermediate chamber proximate to the inlet chamber, a second intermediate chamber proximate to the first intermediate chamber, and a third intermediate chamber proximate to the second intermediate chamber and the outlet chamber. An inlet tube is disposed fluidly connected to the housing and configured to direct a flow of exhaust from the exterior of the housing to the inlet chamber. An outlet tube is disposed fluidly connected to the housing and configured to direct the flow of exhaust from the outlet chamber to the exterior of the housing. A first tube is configured to direct the flow of exhaust from the inlet chamber to one of the plurality of intermediate chambers via an interior of the first tube, and a second tube is configured to direct the flow of exhaust from a second one of the plurality of intermediate chambers to the outlet chamber via an interior of the second tube.
In another aspect of the present disclosure, an apparatus for engine exhaust sound attenuation is described. The apparatus includes a housing having an interior and an exterior, and a plurality of baffle plates arranged within the housing. The baffle plates are disposed apart from each other to define an inlet chamber at a proximal end of the housing, an outlet chamber at a distal end of the housing, and a plurality of intermediate chambers disposed between the inlet chamber and the outlet chamber. The plurality of intermediate chambers includes a first resonant chamber proximate to the outlet chamber, a second resonant chamber proximate to the inlet chamber, a first intermediate chamber proximate to the second resonant chamber, and a second intermediate chamber proximate to the first intermediate chamber and the first resonant chamber. The apparatus further includes an inlet tube disposed fluidly connected to the housing and configured to direct a flow of exhaust from the exterior of the housing to the inlet chamber, an outlet tube disposed fluidly connected to the housing and configured to direct the flow of exhaust from the outlet chamber to the exterior of the housing, a first tube configured to direct the flow of exhaust from the inlet chamber to one of the plurality of intermediate chambers via an interior of the first tube, and a second tube configured to direct the flow of exhaust from a second one of the plurality of intermediate chambers to the outlet chamber via an interior of the second tube.
In yet another aspect of the present disclosure an engine connected with a sound attenuation apparatus is described. The sound attenuation apparatus includes a housing having an interior and an exterior, and a plurality of baffle plates arranged within the housing. The baffle plates are disposed apart from each other to define an inlet chamber at a proximal end of the housing, an outlet chamber at a distal end of the housing, and a plurality of intermediate chambers disposed between the inlet chamber and the outlet chamber. The plurality of intermediate chambers includes a first resonant chamber proximate to the outlet chamber, a second resonant chamber proximate to the inlet chamber, a first intermediate chamber proximate to the second resonant chamber, and a second intermediate chamber proximate to the first intermediate chamber and the first resonant chamber. The apparatus further includes an inlet tube disposed fluidly connected to the housing and configured to direct a flow of exhaust from the exterior of the housing to the inlet chamber, an outlet tube disposed fluidly connected to the housing and configured to direct the flow of exhaust from the outlet chamber to the exterior of the housing, a first tube configured to direct the flow of exhaust from the inlet chamber to one of the plurality of intermediate chambers via an interior of the first tube, and a second tube configured to direct the flow of exhaust from a second one of the plurality of intermediate chambers to the outlet chamber via an interior of the second tube.
The housing 102 is depicted as generally cylindrical in shape having two end wall(s) 114 and a cylindrical side wall 116. The end wall(s) 114 and the cylindrical side wall 116 may be formed of one or more pieces, although they may include several separate pieces welded or otherwise joined together. It should be appreciated that the apparatus 100, although depicted as generally cylindrical, may take other general shapes including an elliptical cylinder, rectangle, etc. The housing 102 may be fabricated of heavy gauge, rust and heat-resistant material such as, for example, sheet metal. For example, the housing 102 may be generally constructed from stainless steel, or another heat and corrosion resistant metallic alloy, heat-resistant carbon fiber, or another suitable material. Under certain sets of circumstances, it is contemplated that the end wall(s) 114 may be removed from, for example, the cylindrical side wall 116 by breaking one or more weldments connecting the end wall(s) 114 and the cylindrical side wall 116. With the end wall(s) 114 removed, various parts or components disposed within the housing interior 104 may be inspected and/or serviced.
The apparatus 100 includes a plurality of baffle plates arranged within the housing interior 104. The plurality of baffle plates can include a first set of identical baffle plates 118 and 120, and a second set of identical baffle plates 122 and 124. The plurality of baffle plates 118-124 may be arranged within the housing interior 104, disposed apart from each other to define an inlet chamber 126 at a proximal end 128 of the apparatus 100, an outlet chamber 130 disposed at a distal end 132 of the apparatus 100, a first intermediate chamber 134 proximate to the inlet chamber 126, a second intermediate chamber 136 proximate to the first intermediate chamber 134, and a third intermediate chamber 138 proximate to the second intermediate chamber 136 and the outlet chamber 130.
In one embodiment, the first set of identical baffle plates includes the baffle plate 118 and the baffle plate 120. The baffle plates 118 and 120 may be configured to be identical to one another with similar dimensions and features such that a single pattern may be used to manufacture both of the baffle plates 118 and 120. This feature may provide ease of manufacturability by reducing design complexity and manufacturing cost. The first set of identical baffle plates 118, 120 may be unperforated to fluidly isolate the inlet chamber 126 from the first intermediate chamber 134, and fluidly isolate the outlet chamber 130 and the third intermediate chamber 138.
In another aspect, the plurality of baffle plates further comprises the baffle plate 122 and the baffle plate 124. The baffle plates 122 and 124 may be referred to, collectively, as the second set of identical baffle plates. The baffle plates 122 and 124 may be configured to provide partial fluid separation between the plurality of intermediate chambers (134, 136, and 138). For example, the baffle plate 122 may be disposed in the housing interior 104 to provide partial fluid separation of the second intermediate chamber 136 and the first intermediate chamber 134. As used herein, partial fluid separation means that fluid, such as the flow of exhaust 110, can freely pass from one chamber to another chamber with minimal impedance from the baffle plate. The impedance may be due to, for example, a perforation pattern having a predetermined ratio of open surface area (e.g., a hole or other opening) to closed surface area (the face of the baffle plate in which the hole or other opening is made). According to one or more embodiments, the predetermined ratio of open surface area to closed surface can be limited to a range of area values that may be observed to target sound attenuation at higher frequencies. For example, although the five-chamber configuration as depicted in
The apparatus 100 further includes a first tube 140 that may be fluidly connected to the inlet chamber 126, and configured to direct the flow of exhaust 110 from the inlet chamber 126 to one of the plurality of intermediate chambers 134, 136, and/or 138 via an interior 142 of the first tube 140. In the embodiment depicted in
In another aspect, the apparatus 100 also includes a second tube 144 configured to direct the flow of exhaust 110 from a second one of the plurality of intermediate chambers 134, 136, and/or 138 to the outlet chamber 130 via an interior 146 of the second tube 144. In the embodiment depicted in
According to embodiments of the present disclosure, the apparatus 100 may incorporate multiple copies of the same part (that is, multiple parts may be identical in that they share the same features and dimensions). For example, the first tube 140 may include features and dimensions that may be the same as corresponding features and dimensions of the second tube 144, such that multiple copies of the one part can (e.g., the first tube 140) may be copied to stand in the place of another part (e.g., the second tube 144). Accordingly, the copied part may be oriented differently from the first part to produce the described sound attenuation without added complexity of multiple designs for custom parts. Two substantially identical parts may share the same feature. One example of such a feature is a perforation pattern having a predetermined ratio of open surface area to closed surface area. Another example of such a feature is a hole in a baffle plate shaped, sized, positioned, and/or otherwise configured to mate with and/or accept the first tube 140 and/or the second tube 144. In a similar respect, the first pair of baffle plates 118 and 120 may be identical parts, where a hole is made in both parts at the same location to accept the inside or outside diameters of the first tube 140 and the second tube 144. Accordingly, the baffle plates 118 and 120 may include identical features.
In another aspect, two parts may share the same dimensions. An example of such a dimension is a diameter measurement for a circular baffle plate (e.g., the baffle plates 118-120). In another example, a shared dimension between identical parts may include a diameter of a hole in the baffle plate 118 that accommodates the first tube 140, such that the first tube 140 may be welded to the baffle plate 118. In another aspect, the first tube 140 may include a same inner diameter as the second tube, a same outer diameter as the second tube 144, and/or a same length as the second tube 144. In the embodiment of
In yet another aspect, parts may be identical (by sharing the same dimensions and features) because they share the same predetermined perforation pattern, shape, length, diameter, etc., such that one of the identical parts may be substituted for another part in the apparatus 100. For example, the first tube 140 may be substituted for the second tube 144, and vice versa. In another example, the first baffle plate 118 may be substituted for the baffle plate 120, and vice versa. As another example, the baffle plate 122 may be substantially identical to the baffle plate 124, such that any one of the baffle plates 122 and 124 may be substituted for the other by orienting at 180 degrees of axial rotation with respect to the other part. It should be appreciated that simplicity in design may be an attribute that may provide many benefits to embodiments of the present disclosure, such as manufacturing efficiencies, as well as reduced inventory for repair and replacement parts.
The apparatus 100 may further include a sound insulating layer 148 disposed on an interior surface of the housing interior 104, wherein the sound insulating layer 148 may be proximate to the flow of exhaust 110. The sound insulating layer 148 may provide a thermal and/or acoustic barrier that impedes sound transfer and heat transfer from the housing interior 104 to the housing exterior 106. In any of the examples described herein, the sound insulating layer 148 may be formed from one or more thermal insulation materials and/or acoustic insulation materials such as a mineral fiber, rockwool, etc. In one aspect, the sound insulating layer 148 may be disposed on an inside surface of the housing interior 104 such that the insulating material can be in direct contact with and/or proximate to the flow of exhaust 110.
The housing 202 may be substantially similar to and/or identical to the housing 102 as depicted in
The apparatus 200 can include a plurality of baffle plates 218, 220, 222, and 224, that may be arranged within the housing interior 204. The plurality of baffle plates 218-224 may be substantially similar and/or identical to the plurality of baffle plates 118-124, depicted with respect to
In one embodiment, the first set of identical baffle plates can include the baffle plate 218 and the baffle plate 220. The baffle plates 218 and 220 may be configured to be identical to one another with similar dimensions and features such that a single pattern may be used to manufacture both of the baffle plates 218 and 220. This feature may provide ease of manufacturability by reducing design complexity and manufacturing cost. The first set of identical baffle plates 218 and 220 may be unperforated to fluidly isolate the inlet chamber 226 from the first intermediate chamber 234, and fluidly isolate the outlet chamber 230 from the third intermediate chamber 238.
In another aspect, the plurality of baffle plates further comprises a baffle plate 222 and a baffle plate 224. The baffle plates 222 and 224 may be referred to, collectively, as a second set of identical baffle plates. The baffle plates 222 and 224 may be configured to provide partial fluid separation between the plurality of intermediate chambers. For example, the baffle plate 222 may be disposed in the housing interior 204 to provide partial fluid separation of the second intermediate chamber 236 and the first intermediate chamber 234. As used herein, partial fluid separation means that fluid such as the flow of exhaust 210 can freely pass from one chamber to another chamber with minimal impedance from the baffle plate. The impedance may be due to, for example, a perforation pattern having a predetermined ratio of open surface area (e.g., a hole or other opening) to closed surface area (the face of the baffle plate in which the hole or other opening is made). According to one or more embodiments, the predetermined ratio of open surface area to closed surface can be limited to a range of area values that may be observed to target sound attenuation at higher frequencies. For example, although the five-chamber configuration as depicted in
The apparatus 200 may further include a first tube 240 configured to direct the flow of exhaust 210 from the inlet chamber 226 to one of the plurality of intermediate chambers 234, 236, and/or 238 via an interior 242 of the first tube 240. In the embodiment depicted in
In another aspect, the apparatus 200 also includes a second tube 244 configured to direct the flow of exhaust 210 from a second one of the plurality of intermediate chambers 234, 236, and/or 238 to the outlet chamber 230 via an interior 246 of the second tube 244. In the embodiment depicted in
According to embodiments of the present disclosure, and similar to the embodiment described with respect to
The apparatus 200 may further include a sound insulating layer 248 disposed on an interior surface of the housing interior 204, wherein the sound insulating layer 248 is proximate to the flow of exhaust 210. The sound insulating layer 248 may be substantially similar and/or identical to the sound insulating layer 148, in that it may provide a thermal and/or acoustic barrier that impedes sound transfer and heat transfer from the housing interior 204 to the housing exterior 206. In one aspect, the sound insulating layer 248 may be disposed on an inside surface of the housing interior 204 such that the sound insulating layer 248 may be in direct contact with and/or proximate to the flow of exhaust 210.
In one aspect, the inlet tube 308 may terminate at a surface of the housing interior 304. The end of the inlet tube 308 that touches the housing interior 304 may be fluidly sealed by welding or by another means for mechanically coupling the open end of the inlet tube 308 to the housing interior 304. In another aspect, a portion of the inlet tube 308 in the inlet chamber 326 comprises the perforated section 354 having the predetermined ratio of open surface area to closed surface area as described above with respect to
In another aspect, outlet tube 312 may terminate at a surface of the housing interior 304 in an outlet chamber 330. The end of the outlet tube 312 that touches the housing interior 304 may be fluidly sealed by welding or by another means for mechanically coupling the open end of the outlet tube 312 to the housing interior 304. In another aspect, a portion of the outlet tube 312 in the outlet chamber 330 comprises the perforated section 356 having the predetermined ratio of open surface area to closed surface area as described above with respect to
The housing 302 may be substantially similar to and/or identical to the housing 102 as depicted in
The apparatus 300 can include a plurality of baffle plates arranged within the housing interior 304. The plurality of baffle plates (318, 320, 322, and 324), may be substantially similar and/or identical to the baffle plates depicted with respect to
In one embodiment, the first set of identical baffle plates can include the baffle plate 318 and the baffle plate 320. The baffle plates 318 and 320 may be configured to be identical to one another with similar dimensions and features such that a single pattern may be used to manufacture both of the baffle plates 318 and 320. This feature may provide ease of manufacturability by reducing design complexity and manufacturing cost. The first set of identical baffle plates 318, 320 may be unperforated to fluidly isolate the inlet chamber 326 from the first intermediate chamber 334, and fluidly isolate the outlet chamber 330 from the third intermediate chamber 338.
In another aspect, the plurality of baffle plates further comprises a baffle plate 322 and a baffle plate 324. The baffle plates 322 and 324 may be referred to, collectively, as a second set of identical baffle plates. The baffle plates 322 and 324 may be configured to provide partial fluid separation between the plurality of intermediate chambers. For example, the baffle plate 322 may be disposed in the housing interior 304 to provide partial fluid separation of the second intermediate chamber 336 and the first intermediate chamber 334. As used herein, partial fluid separation means that fluid such as the flow of exhaust 310 can freely pass from one chamber to another chamber with minimal impedance from a respective baffle plate having partial fluid separation. The impedance may be due to, for example, a perforation pattern having a predetermined ratio of open surface area (e.g., a hole or other opening) to closed surface area (the face of the baffle plate in which the hole or other opening is made). According to one or more embodiments, the predetermined ratio of open surface area to closed surface can be limited to a range of area values that may be observed to target sound attenuation at higher frequencies. For example, although the five-chamber configuration as depicted in
The apparatus 300 may further include a first tube 340 configured to direct the flow of exhaust 310 from the inlet chamber 326 to one of the plurality of intermediate chambers 334, 336, and/or 338 via an interior 342 of the first tube 340. In the embodiment depicted in
In another aspect, the apparatus 300 also includes a second tube 344 configured to direct the flow of exhaust 310 from a second one of the plurality of intermediate chambers 334, 336, and/or 338 to the outlet chamber 330 via an interior 346 of the second tube 344. In the embodiment depicted in
According to embodiments of the present disclosure, and similar to the embodiment described with respect to
The apparatus 300 may further include a sound insulating layer 348 disposed on an interior surface of the housing interior 304, wherein the sound insulating layer may be proximate to the flow of exhaust. The sound insulating layer 348 may be substantially similar and/or identical to the sound insulating layer 248 and/or 148. In one aspect, the sound insulating layer 348 may be configured on an inside surface of the housing interior 304 such that the sound insulating layer 348 may be in direct contact and/or proximate to the flow of exhaust 310.
In one aspect, the inlet tube 408 and the outlet tube 412 may be disposed axially aligned with a longitudinal axis (not shown in
The housing 402 may be substantially similar to and/or identical to the housing 102, 202, and/or 302, as respectively depicted in
The apparatus 400 can include a plurality of baffle plates arranged within the housing interior 404. The plurality of baffle plates as shown in
In some aspects, it may be desirable to attenuate overall sound approximately 25-33 dB with the sound attenuation apparatuses as describe with respect to
In other aspects, the relative sizes of chambers within the apparatus 400, as well as their configuration as the resonant chambers 454 and 456, or the intermediate chambers 434 and 436 may also attenuate particular (targeted) frequencies of noise content. For example, the resonant chambers 454 and 456 may target specific frequencies of noise content based on relative size of the chamber with respect to other chamber sizes. In one aspect, the first resonant chamber 454, being the smallest chamber of the apparatus 400, may be configured to target approximately 200 Hz to 500 Hz exhaust noise. In other aspects, the second resonant chamber 456 may be configured to attenuate mid-range frequencies (approximately 100 Hz-200 Hz) exhaust noise.
In one embodiment, the plurality of baffle plates may include the baffle plate 418 and the baffle plate 420, referred to herein as a first set of identical baffle plates. The baffle plates 418 and 420 may be configured to be identical to one another with similar dimensions and features such that a single pattern may be used to manufacture both of the baffle plates 418 and 420. This feature may provide ease of manufacturability by reducing design complexity and manufacturing cost. The first set of identical baffle plates 418, 420 may be unperforated to fluidly isolate the inlet chamber 426 from the second resonant chamber 456, and fluidly separate the outlet chamber 430 from the first resonant chamber 454.
In another aspect, the plurality of baffle plates may further include the baffle plate 422 and the baffle plate 424, referred to collectively as a second set of identical baffle plates. The baffle plates 422 and 424 may be configured to fluidly isolate the plurality of intermediate chambers from the resonant chambers 454 and 456. For example, the baffle plate 422 may be disposed in the housing interior 404 to fluidly isolate the first intermediate chamber 434 from the second resonant chamber 456. As explained previously, full fluid separation (and/or fluid isolation) means that fluid such as the flow of exhaust 410 cannot freely pass from one chamber to another chamber, because the baffle plate does not have perforations that allow gas flow. On the other hand, the center baffle plate 425 may be configured for partial fluid separation such that the flow of exhaust 410 can pass freely with minimal impedance from the second intermediate chamber 436 to the first intermediate chamber 434. The impedance may be due to a perforation pattern having the predetermined ratio of open surface area (e.g., a hole or other opening) to closed surface area (the face of the baffle plate in which the hole or other opening is made) as described with respect to
The apparatus 400 may further include a first tube 440 configured to direct the flow of exhaust 410 from the inlet chamber 426 to the second intermediate chamber 436 via an interior 442 of the first tube 440. The first tube 440 may extend from and fluidly connect the inlet chamber 426 to the second intermediate chamber 436. In one aspect, the first tube 440 terminates at a surface of the baffle plate 424. The end of the first tube 440 in contact with the baffle plate 424 may be fluidly sealed with the baffle plate 424 at the end of the tube by welding or another method. A portion of the first tube 440 in the second intermediate chamber 436 may incorporate a perforated section 452 having the predetermined ratio of open surface area to closed surface area (described previously with respect to
Although the first tube 440 may be sealed at the end to the baffle plate 424, an acoustic channel 458 may be formed by an opening (or plurality of openings) in the baffle plate 424 to acoustically connect the interior 442 of the first tube 440 with the first resonant chamber 454. Since the first resonant chamber 454 does not include an outlet to direct the flow of exhaust 410, the first resonant chamber 454 may function as a mid-high frequency sound attenuation chamber. The acoustic channel 458 may include a single hole substantially smaller than an inside diameter of the first tube 440, or a plurality of holes (e.g., such as, for example, the perforation pattern described above).
In another aspect, the apparatus 400 also includes a second tube 444 configured to direct the flow of exhaust 410 from a second one of the plurality of intermediate chambers 434 and/or 436 to the outlet chamber 430 via an interior 446 of the second tube 444. In the embodiment depicted in
Although the second tube 444 may be sealed at the end to the baffle plate 422, an acoustic channel 460 may be disposed in the baffle plate 422 to acoustically connect the interior 446 of the second tube 444 with the second resonant chamber 456. Since the second resonant chamber 456 does not include an outlet to direct the flow of exhaust 410, the second resonant chamber 456 may function as a high frequency sound attenuation chamber that targets low-mid range frequency noise ranging from approximately 100 Hz to approximately 200 Hz. The acoustic channel 460 may include a single hole substantially smaller than a diameter of the second tube 444, or a plurality of holes (e.g., such as, for example, the perforation pattern described above). It should also be appreciated that the relative size of the second resonant chamber 456 is associated with the targeted frequency of sound attenuation. For example, because sound attenuation is associated with size (that is, volume) of the chambers, the larger volume of the second resonant chamber 456 may attenuate lower frequencies (e.g., approximately 0-100 Hz) than the relatively smaller volume of the first resonant chamber 454.
According to embodiments of the present disclosure, and similar to the embodiment described with respect to
The apparatus 400 may further include a sound insulating layer 448 disposed on an interior surface of the housing interior 404, wherein the sound insulating layer may be proximate to the flow of exhaust. The sound insulating layer 448 may be substantially similar and/or identical to the sound insulating layer 448, in that it may provide a thermal and/or acoustic barrier that impedes sound transfer and heat transfer from the housing interior 404 to the housing exterior 406. In one aspect, the sound insulating layer 448 may be configured on an inside surface of the housing interior 404 such that the insulating material may be in direct contact and/or proximate to the flow of exhaust 410.
The present disclosure provides apparatuses for sound attenuation for internal combustion-type motors that target specific frequencies of noise content. According to embodiments of the present disclosure, the apparatuses may attenuate noise to noise reduction levels to approximately 30 dB or more, across a wide spectrum of noise content (e.g., from approximately 0 Hz to approximately 5000 Hz). Moreover, embodiments described herein can minimize cost associated with manufacturing the apparatuses with reduced system complexity, and by incorporation of multiple copies of standardized parts.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
