Patent Publication Number: US-11391195-B2

Title: Exhaust system and muffler

Description:
TECHNICAL FIELD 
     The present disclosure relates to an exhaust system for an engine. More particularly, the present disclosure relates to a muffler of an exhaust system for an engine. 
     BACKGROUND 
     An exhaust system for an internal combustion engine employs a muffler in order to dampen exhaust noise generated by the engine. In a multi-cylinder internal combustion engine, two different exhaust streams may be generated by two different banks of cylinders. The two exhaust streams may flow into the muffler from two different portions of an exhaust manifold through two different exhaust pipes. In many situations, a length of each of the exhaust pipes may be different from each other, such as due to different routing arrangement of each of the exhaust pipes, location of the engine, location of various vehicle components around each of the exhaust pipes, and so on. Due to difference in lengths between the exhaust pipes, a corresponding engine order noise may be generated downstream of the exhaust pipes. 
     SUMMARY 
     In an aspect of the present disclosure, a muffler for use with an engine is provided. The muffler includes a first tube defining a first inlet and a first outlet spaced apart from the first inlet. The first tube is configured to receive exhaust from the engine at the first inlet. The muffler includes a second tube spaced apart from the first tube. The second tube defines a second inlet and a second outlet spaced apart from the second inlet. The second tube is configured to receive exhaust from the engine at the second inlet. The muffler also includes a third tube disposed at least partly around the second tube. The third tube defines a third outlet spaced apart from each of the second inlet and the second outlet. The third outlet is in fluid communication with the second outlet of the second tube. The muffler further includes at least one outlet tube in fluid communication with the first outlet and the third outlet. 
     In another aspect of the present disclosure, an exhaust system for use with an engine having a first row of cylinders and a second row of cylinders is provided. The exhaust system includes a first pipe configured to receive exhaust from the first row of cylinders. The exhaust system also includes a second pipe configured to receive exhaust from the second row of cylinders. The exhaust system further includes a muffler. The muffler includes a first tube defining a first inlet and a first outlet spaced apart from the first inlet. The first inlet is in fluid communication with the first pipe. The muffler includes a second tube spaced apart from the first tube. The second tube defines a second inlet and a second outlet spaced apart from the second inlet. The second tube is in fluid communication with the second pipe. The muffler also includes a third tube disposed at least partly around the second tube. The third tube defines a third outlet spaced apart from each of the second inlet and the second outlet. The third outlet is in fluid communication with the second outlet of the second tube. The muffler further includes at least one outlet tube in fluid communication with the first outlet and the third outlet. 
     In yet another aspect of the present disclosure, a muffler for use with an engine is provided. The muffler includes a first tube defining a first inlet and a first outlet spaced apart from the first inlet. The first tube is configured to receive exhaust from the engine at the first inlet. The muffler includes a second tube spaced apart from the first tube. The second tube defines a second inlet and a second outlet spaced apart from the second inlet. The second tube is configured to receive exhaust from the engine at the second inlet. The muffler includes a third tube disposed at least partly around the second tube. The third tube defines a third outlet spaced apart from each of the second inlet and the second outlet. The third outlet is in fluid communication with the second outlet of the second tube. The muffler also includes a housing at least partly enclosing the first tube, the second tube and the third tube. The housing defines a common chamber in fluid communication with the first outlet and the third outlet. The muffler further includes at least one outlet tube in fluid communication with the common chamber. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic representation of an exhaust system coupled to an engine, according to an aspect of the present disclosure; 
         FIGS. 2A and 2B  are different perspective views of a muffler, according to an aspect of the present disclosure; 
         FIGS. 2C and 2D  are different perspective views of the muffler of  FIG. 2A  without an outer shell, according to an aspect of the present disclosure; 
         FIG. 2E  is a cross-sectional view of the muffler of  FIG. 2A  along a section A-A′, according to an aspect of the present disclosure; 
         FIGS. 3A and 3B  are exemplary graphical representations of a performance of the muffler of  FIG. 2A  with respect to a conventional muffler; 
         FIGS. 4A and 4B  are different perspective views of another muffler, according to another aspect of the present disclosure; 
         FIGS. 4C and 4D  are different perspective views of the muffler of  FIG. 4A  without an outer shell, according to an aspect of the present disclosure; 
         FIG. 5  is a schematic representation of another exhaust system coupled to the engine, according to an aspect of the present disclosure; 
         FIG. 6  is a cross-sectional view of another muffler, according to another aspect of the present disclosure; and 
         FIGS. 7A to 7D  are schematic representations of different exemplary arrangements of a second tube and a third tube of another muffler, according to an aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Referring to  FIG. 1 , an exemplary schematic representation of an exhaust system  100  coupled to an engine  102  is illustrated. The engine  102  may be any internal combustion engine powered by a fuel, such as gasoline, diesel, natural gas, and so on, or a combination thereof. The engine  102  is a multi-cylinder engine. Accordingly, the engine  102  includes two rows of cylinders, such as a first row of cylinders  104  and a second row of cylinders  106 . The first row of cylinders  104  and the second row of cylinders  106  may correspond to two cylinder banks of the engine  102 . In the illustrated embodiment, each of the first row of cylinders  104  and the second row of cylinders  106  includes three cylinders. In other embodiments, each of the first row of cylinders  104  and the second row of cylinders  106  may include any number of cylinders, based on application requirements. Also, in the illustrated embodiment, the engine  102  has a V-configuration. In other embodiments, the engine  102  may have any other configuration, such as an inline or straight configuration, and so on, based on application requirements. 
     The exhaust system  100  includes a first exhaust manifold  108  and a second exhaust manifold  110 . The first exhaust manifold  108  is coupled to the first row of cylinders  104 . Accordingly, the first exhaust manifold  108  is adapted to receive a first exhaust stream “E 1 ” from the first row of cylinders  104 . The second exhaust manifold  110  is coupled to the second row of cylinders  106 . Accordingly, the second exhaust manifold  110  is adapted to receive a second exhaust stream “E 2 ” from the second row of cylinders  106 . Additionally, the engine  102  may include components and/or systems not described herein, such as an engine block, a cylinder head, a valve assembly, an intake manifold, a cooling system, a lubrication system, an air delivery system, a turbocharger, a supercharger, other peripherals, and so on, based on application requirements. 
     The exhaust system  100  also includes a muffler  112 . The muffler  112  is coupled to each of the first exhaust manifold  108  and the second exhaust manifold  110 . More specifically, the muffler  112  is coupled to the first exhaust manifold  108  via a first pipe  114 . The first pipe  114  defines a first pipe length “LP 1 ”. The first pipe  114  is adapted to provide flow of the first exhaust stream “E 1 ” from the first exhaust manifold  108  to the muffler  112 . Also, the muffler  112  is coupled to the second exhaust manifold  110  via a second pipe  116 . The second pipe  116  defines a second pipe length “LP 2 ”. The second pipe  116  is adapted to provide flow of the second exhaust stream “E 2 ” from the second exhaust manifold  110  to the muffler  112 . 
     In the illustrated embodiment, the first pipe length “LP 1 ” of the first pipe  114  is greater than the second pipe length “LP 2 ” of the second pipe  116 . In other embodiments, the second pipe length “LP 2 ” of the second pipe  116  may be greater than the first pipe length “LP 1 ” of the first pipe  114 . As such, a travel length of the first exhaust stream “E 1 ” through the first pipe  114  is greater than a travel length of the second exhaust stream “E 2 ” through the second pipe  116 . Due to a difference in the travel length of each of the first exhaust stream “E 1 ” and the second exhaust stream “E 2 ”, a half engine order noise may be created downstream of each of the first pipe  114  and the second pipe  116 . Accordingly, the muffler  112  may be adapted to limit the half engine order noise downstream of each of the first pipe  114  and the second pipe  116 . Additionally, the exhaust system  100  may include one or more aftertreatment components/systems (not shown), such as a Diesel Particulate Filter (DPF) unit, a Diesel Oxidation Catalyst (DOC) unit, a Diesel Exhaust Fluid (DEF) unit, a Selective Catalytic Reduction (SCR) unit, a tailpipe, and so on, based on application requirements. 
     Referring to  FIGS. 2A, 2B, 2C, and 2D , different perspective views of one embodiment of a muffler  202  are illustrated. Referring to  FIG. 2E , a cross-sectional view of the muffler  202  along a section A-A′ (shown in  FIGS. 2A and 2B ) is illustrated. The muffler  202  will now be explained with combined reference to  FIGS. 2A to 2E . The muffler  202  includes a housing  204  defining a longitudinal axis L-L′ of the muffler  202 . In the illustrated embodiment, the housing  204  has a substantially elliptical and elongated configuration. In other embodiments, the housing  204  may have any other configuration, such as rectangular, cylindrical, and so on, based on application requirements. The housing includes an outer shell  205 . The housing  204  defines a first side  206  and a second side  208  disposed opposite to the first side  206 . The housing  204  includes a first end plate  210  disposed on the first side  206  and connected to the outer shell  205 . The housing  204  also includes a second end plate  212  disposed on the second side  208  and connected to the outer shell  205 . 
     The muffler  202  includes a first internal plate  214 , a second internal plate  216 , and a third internal plate  218 . Each of the first internal plate  214 , the second internal plate  216 , and the third internal plate  218  is disposed within the housing  204 . Also, each of the first end plate  210 , the second end plate  212 , the first internal plate  214 , the second internal plate  216 , and the third internal plate  218  is disposed substantially parallel to and spaced apart from one another. Accordingly, the muffler  202  includes a common chamber  220  disposed between the first internal plate  214  and the second internal plate  216 . The muffler  202  also includes a first chamber  222  disposed between the first end plate  210  and the first internal plate  214 . The muffler  202  also includes a second chamber  224  disposed between the second internal plate  216  and the third internal plate  218 . The muffler  202  further includes a third chamber  226  disposed between the second end plate  212  and the third internal plate  218 . 
     The muffler  202  includes a first tube  228  disposed at least partly within the housing  204 . The first tube  228  defines a first length “L 1 ”. The first tube  228  is at least partially disposed in the first chamber  222  extending between the first end plate  210  and the first internal plate  214 . More specifically, the first tube  228  extends out from each of the first end plate  210  and the first internal plate  214 . The first tube  228  defines a first inlet  230  and a first outlet  232  disposed spaced apart from the first inlet  230 . In the illustrated embodiment, the first outlet  232  is disposed opposite to the first inlet  230 . In other embodiments, the first outlet  232  may be disposed on a wall (not shown) of the first tube  228  and spaced apart from the first inlet  230 . In such a situation, an end of the first tube  228  disposed distally opposite to the first inlet  230  may be closed. The first inlet  230  is disposed on the first end plate  210 . The first inlet  230  is adapted to be fluidly coupled to the first pipe  114 . Accordingly, the first inlet  230  is adapted to receive the first exhaust stream “E 1 ” from the first pipe  114  into the first tube  228 . The first outlet  232  is disposed on the first internal plate  214  and in fluid communication with the common chamber  220 . Accordingly, the first outlet  232  is adapted to discharge the first exhaust stream “E 1 ” from the first tube  228  into the common chamber  220 . 
     The muffler  202  includes a second tube  234  disposed at least partly within the housing  204 . The second tube  234  defines a second length “L 2 ”. The second length “L 2 ” of the second tube  234  is greater than the first length “L 1 ” of the first tube  228 . The second tube  234  is disposed substantially parallel to and spaced apart from the first tube  228 . The second tube  234  is disposed in each of the first chamber  222 , the common chamber  220 , and the second chamber  224  and extends between the first end plate  210 , the first internal plate  214 , and the second internal plate  216 . The second tube  234  defines a second inlet  236  and a second outlet  238 . The second inlet  236  is disposed spaced apart from the second outlet  238  along the longitudinal axis L-L′. The second inlet  236  is disposed on the first end plate  210 . The second inlet  236  is adapted to be fluidly coupled to the second pipe  116 . Accordingly, the second inlet  236  is adapted to receive the second exhaust stream “E 2 ” from the second pipe  116  into the second tube  234 . In the illustrated embodiment, the second outlet  238  is disposed opposite to the second inlet  236  and within the second chamber  224 . In other embodiments, the second outlet  238  may be disposed on a wall  240  of the second tube  234  spaced apart from the second inlet  236  and within the second chamber  224 . In such a situation, a distal end  242  of the second tube  234  may be closed. 
     The muffler  202  also includes a third tube  244  disposed within the housing  204 . The third tube  244  defines a third length “L 3 ”. The third length “L 3 ” of the third tube  244  is greater than the first length “L 1 ” of the first tube  228 . Accordingly, a sum of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  is greater than the first length “L 1 ” of the first tube  228 . In other embodiments, each of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  may be smaller than the first length “L 1 ” of the first tube  228 . However, the sum of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  may be greater than the first length “L 1 ” of the first tube  228 . The third tube  244  is disposed substantially parallel to and spaced apart from each of the first tube  228  and the second tube  234 . Also, the third tube  244  is disposed at least partly around the second tube  234 . 
     More specifically, the third tube  244  is disposed concentrically around the second tube  234 , such that a portion of the third tube  244  overlaps the second tube  234  defining an overlap length “OL” and a reversal length “RL”. As such, the third length “L 3 ” of the third tube  244  is equal to a sum of the overlap length “OL” and the reversal length “RL”. Alternatively, the third tube  244  may be eccentrically disposed around the second tube  234 . The third tube  244  is disposed in each of the common chamber  220  and the second chamber  224 . The third tube  244  defines a third outlet  246 . The third outlet  246  is spaced apart from each of the second inlet  236  and the second outlet  238  of the second tube  234 . Additionally, the third outlet  246  is disposed axially between the second inlet  236  and the second outlet  238  of the second tube  234  relative to the longitudinal axis L-L′. Also, the third outlet  246  is provided in fluid communication with the second outlet  238  of the second tube  234  through a gap  248  provided between the second tube  234  and the third tube  244 . The gap  248  may be an annular gap between the second tube  234  and the third tube  244 . 
     The third tube  244  also includes a closed end  250  defined by an end wall  249  disposed opposite to the third outlet  246  relative to the longitudinal axis L-L′. More specifically, the closed end  250  is axially spaced apart from the second outlet  238  of the second tube  234  relative to the longitudinal axis L-L′. Accordingly, the second outlet  238  of the second tube  234  is axially disposed between the closed end  250  and the third outlet  246  of the third tube  244 . The second outlet  238  of the second tube  234  is adapted to discharge the second exhaust stream “E 2 ” within the third tube  244  into a reversal portion  251 . The reversal portion  251  defines the reversal length “RL”. The third tube  244  is adapted to receive the second exhaust stream “E 2 ” from the second outlet  238  of the second tube  234  into the reversal portion  251  and to allow flow of the second exhaust stream “E 2 ” through the gap  248 . The third outlet  246  is provided in fluid communication with the common chamber  220 . Accordingly, the third outlet  246  is adapted to discharge the second exhaust stream “E 2 ” into the common chamber  220 . 
     The muffler  202  also includes a connecting member  252  disposed between the second tube  234  and the third tube  244 . More specifically, the connecting member  252  is disposed adjacent to the third outlet  246 . The connecting member  252  is adapted to connect the second tube  234  to the third tube  244  and provide structural rigidity between the second tube  234  and the third tube  244 . The connecting member  252  includes a first part  288  connected to an outer surface of the second tube  234 , a second part  290  extending from the first part  288 , and a third part  292  connected to an outer surface of the third tube  244 . The second part  290  is inclined to each of the first part  288  and the third part  292 . The first part  288  and the third part  292  are substantially parallel to each other. The first part  288  may be connected to the second tube  234  by various methods, such as welding, adhesives, mechanical joints, fasteners, and so forth. Similarly, the third part  292  may be connected to the third tube  244  by various methods, such as welding, adhesives, mechanical joints, fasteners, and so forth. 
     In the illustrated embodiment, the muffler  202  includes a single connecting member  252 . In other embodiments, the muffler  202  may include multiple connecting members, such that each of the multiple connecting members may be disposed at any location between the second tube  234  and the third tube  244 . In yet other embodiments, the second tube  234  may be connected to the third tube  244  using any other coupling method, such as a pin-type weld, a pipe-to-pipe joint, and so on. Alternatively, in some embodiments, each of the second tube  234  and the third tube  244  may be connected to any of the first end plate  210 , the first internal plate  214 , the second internal plate  216 , and/or the third internal plate  218 , based on application requirements, such that the second tube  234  and the third tube  244  may have a pipe-on-pipe configuration. 
     The muffler  202  further includes a number of outlet tubes, such as a first outlet tube  254  and a second outlet tube  256 , disposed at least partly within the housing  204 . Each of the first outlet tube  254  and the second outlet tube  256  is disposed substantially parallel to and spaced apart from one another and each of the first tube  228 , the second tube  234 , and the third tube  244 . Each of the first outlet tube  254  and the second outlet tube  256  is disposed in each of the first chamber  222 , the common chamber  220 , the second chamber  224 , and the third chamber  226  and extends between the first internal plate  214 , the second internal plate  216 , the third internal plate  218 , and the second end plate  212 . Each of the first outlet tube  254  and the second outlet tube  256  is provided in fluid communication with the first outlet  232  of the first tube  228  and the third outlet  246  of the third tube  244  via the common chamber  220 . The first outlet tube  254  includes an inlet end  258  and an outlet end  262 . Similarly, the second outlet tube  256  includes an inlet end  260  and an outlet end  264 . Each of the outlet ends  262 ,  264  is disposed opposite to the respective inlet ends  258 ,  260  relative to the longitudinal axis L-L′. 
     Each of the inlet ends  258 ,  260  is disposed on the first internal plate  214  and in fluid communication with the common chamber  220 . Accordingly, the first outlet tube  254  and the second outlet tube  256  are adapted to receive a third exhaust stream “E 3 ” and a fourth exhaust stream “E 4 ” from the common chamber  220  via the inlet ends  258 ,  260 , respectively. Each of the outlet ends  262 ,  264  is disposed on the second end plate  212 . Further, each of the outlet ends  262 ,  264  may be fluidly coupled to a downstream component (not shown) of the exhaust system  100 , such as the tailpipe. Accordingly, the outlet ends  262 ,  264  are adapted to discharge the third exhaust stream “E 3 ” and the fourth exhaust stream “E 4 ” from the first outlet tube  254  and the second outlet tube  256 , respectively, out of the muffler  202 . 
     The muffler  202  also includes a first branch tube  266  and a second branch tube  268 . The first branch tube  266  and the second branch tube  268  are coupled to the first outlet tube  254  and the second outlet tube  256 , respectively. Also, each of the first branch tube  266  and the second branch tube  268  is disposed within the housing  204  and within the third chamber  226 . The first branch tube  266  and the second branch tube  268  are adapted to discharge a portion of the third exhaust stream “E 3 ” and a portion of the fourth exhaust stream “E 4 ” from the first outlet tube  254  and the second outlet tube  256 , respectively, into the third chamber  226 . As such, each of the first branch tube  266  and the second branch tube  268  is adapted to improve tuning of the muffler  202  and/or limit a pressure differential between the third chamber  226  and each of the first outlet tube  254  and the second outlet tube  256 , respectively. The first and second branch tubes  266 ,  268  may therefore act as side branch tuners for the muffler  202 . 
     Additionally, the muffler  202  includes a reinforcing rod  270  extending between each of the first internal plate  214  and the second internal plate  216 . The reinforcing rod  270  is disposed substantially parallel to and spaced apart from each of the first tube  228 , the second tube  234 , the third tube  244 , the first outlet tube  254 , and the second outlet tube  256 . The reinforcing rod  270  is adapted to provide structural rigidity to each of the first internal plate  214  and the second internal plate  216 . In other embodiments, the reinforcing rod  270  may be, additionally or optionally, provided between the first end plate  210  and the first internal plate  214 , the second internal plate  216  and the third internal plate  218 , and/or the third internal plate  218  and the second end plate  212 . 
     During operation, the first exhaust stream “E 1 ” is received into the muffler  202  from the first pipe  114  (shown in  FIG. 1 ) via the first inlet  230  of the first tube  228  and is discharged into the common chamber  220  via the first outlet  232  of the first tube  228 , as shown by an arrow  272 . The second exhaust stream “E 2 ” is received into the muffler  202  from the second pipe  116  (shown in  FIG. 1 ) via the second inlet  236  of the second tube  234  and is discharged into the third tube  244  via the second outlet  238  of the second tube  234 , as shown by an arrow  274 . Due to the closed end  250  of the third tube  244 , the second exhaust stream “E 2 ” deflects in the reversal portion  251  and flows into the gap  248 , as shown by an arrow  276 , and is further discharged into the common chamber  220  via the third outlet  246  of the third tube  244 , as shown by an arrow  278 . 
     As the second exhaust stream “E 2 ” flows through the muffler  202 , the second exhaust stream “E 2 ” travels a distance approximately equal to the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116 . More specifically, the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116  may be approximately equal to a sum of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  less the first length “L 1 ” of the first tube  228 , i.e., (LP 1 −LP 2 ) may be approximately equal to [(L 2 +L 3 )−L 1 ]. As such, each of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  compensates for the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116 , in turn, decreasing the half engine order noise downstream of the muffler  202 . 
     In other words, the sum of the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244  is greater than the first length “L 1 ” of the first tube  228 , i.e., (L 2 +L 3 ) is greater than (L 1 ). Accordingly, the half engine order noise generated due to the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116  is decreased. Therefore, (L 2 +L 3 ) is greater than (L 1 ) such that the half engine order noise downstream of the muffler  202  is decreased. In such a situation, a sum of the first pipe length “LP 1 ” of the first pipe  114  and the first length “L 1 ” of the first tube  228  is approximately equal to a sum of the second pipe length “LP 2 ” of the second pipe  116 , the second length “L 2 ” of the second tube  234  and the third length “L 3 ” of the third tube  244 , i.e., (LP 1 +L 1 ) is approximately equal to (LP 2 +L 2 +L 3 ) in order to decrease the half engine order noise downstream of the muffler  202 . The second and third tubes  234 ,  244  may therefore allow flow reversal of the second exhaust stream “E 2 ”, thereby increasing a flow length of the second exhaust stream “E 2 ” with respect to the first exhaust stream “E 1 ”. Accordingly, the travel length of the second exhaust stream “E 2 ” through the second pipe  116 , the second tube  234  and the third tube  244  is approximately equal to the travel length of the first exhaust stream “E 1 ” through the first pipe  114  and the first tube  228 . Further, the overlap between the second and third tubes  234 ,  244  may provide a compact configuration without reducing the flow length through the second and third tubes  234 ,  244 . 
     The first exhaust stream “E 1 ” and the second exhaust stream “E 2 ” mix with each other within the common chamber  220  forming a mixed exhaust stream. The mixed exhaust stream flows into the first chamber  222  from the common chamber  220 , as shown by arrows  280 , via one or more apertures  282  provided on the first internal plate  214 . In the illustrated embodiment, the first internal plate  214  includes a number of such apertures  282  with different shapes, such as rectangular, circular, oval and so forth. A number and shapes of the apertures  282  may be varied as per application requirements. In some situations, a portion of the mixed exhaust stream may also flow into the second chamber  224  from the common chamber  220 , as shown by an arrow  284 , via one or more apertures  286  provided on the second internal plate  216 . The portion of the mixed exhaust stream may flow into the second chamber  224  from the common chamber  220  based on a pressure differential between the common chamber  220  and the second chamber  224 . In the illustrated embodiment, the second internal plate  216  includes one such aperture  286  with a polygonal shape. A number and shapes of the apertures  286  may be varied as per application requirements. 
     Further, the mixed exhaust stream present in the common chamber  220  divides into the third exhaust stream “E 3 ” and the fourth exhaust stream “E 4 ” such that the third exhaust stream “E 3 ” flows into the first outlet tube  254  via the inlet end  258 , and the fourth exhaust stream “E 4 ” flows into the second outlet tube  256  via the inlet end  260 . The third exhaust stream “E 3 ” flows through the first outlet tube  254  and is discharged out of the muffler  202  via the outlet end  262 . A portion of the third exhaust stream “E 3 ” may be discharged into the third chamber  226  via the first branch tube  266  based on the pressure differential between the first outlet tube  254  and the third chamber  226 , in turn, improving tuning of the muffler  202 . Also, the fourth exhaust stream “E 4 ” flows through the second outlet tube  256  and is discharged out of the muffler  202  via the outlet end  264 . A portion of the fourth exhaust stream “E 4 ” may be discharged into the third chamber  226  via the second branch tube  268  based on the pressure differential between the second outlet tube  256  and the third chamber  226 , in turn, improving tuning of the muffler  202 . 
     The configuration of the muffler  202 , as shown in  FIGS. 2A to 2E , are exemplary in nature and alternative configurations are possible within the scope of the present disclosure. For example, though the first, second and third tubes  228 ,  234 ,  244  are illustrated as substantially straight hollow cylindrical tubes, the first, second and/or third tubes  228 ,  234 ,  244  may have alternative shapes, such as curvilinear with non-circular cross-sections. 
     Referring to  FIG. 6 , a cross sectional view of another embodiment of a muffler  602  is illustrated. The muffler  602  has a configuration substantially similar to the configuration of the muffler  202 . As such, the muffler  602  includes the housing  204  having the first side  206 , the second side  208 , the first end plate  210 , the second end plate  212 , the first internal plate  214 , the second internal plate  216 , the third internal plate  218 , the common chamber  220 , the first chamber  222 , the second chamber  224 , and the third chamber  226 . The muffler  602  also includes the first tube  228  having the first inlet  230  and the first outlet  232 . The muffler  602  also includes the connecting member  252  having the first part  288 , the second part  290 , and the third part  292 . The muffler  602  also includes the first outlet tube  254  having the inlet end  258  and the outlet end  262 , the second outlet tube  256  having the inlet end  260  and the outlet end  264 , the first branch tube  266 , the second branch tube  268 , and the reinforcing rod  270 . The muffler  602  also includes the aperture  282  and the aperture  286 . 
     In the illustrated embodiment, the muffler  602  includes a second tube  634  having a second inlet  636 , a second outlet  638 , a wall  640 , and a closed end  642  defined by an end wall  643 . The wall  640  extends between the second inlet  636  and the end wall  643 . The end wall  643  and the closed end  642  are disposed axially opposite to the second inlet  636 . The second outlet  638  is defined by one or more openings  639  disposed on the wall  640 . The one or more openings  639  are through holes disposed on the wall  640 . In case of multiple openings  639 , the openings  639  may be angularly and/or axially separated from each other. A number, a shape and dimensions of each opening  639  may be varied as per application requirements. The second outlet  638  is disposed adjacent to the end wall  643  and the closed end  642 . Also, the second outlet  638  is disposed spaced apart from the second inlet  636  and within the second chamber  224 . 
     The muffler  602  also includes a third tube  644  having a third outlet  646 . The third tube  644  is disposed concentrically around the second tube  634  forming a gap  648  therebetween. The third outlet  646  is provided in fluid communication with the second outlet  638  of the second tube  634  through the gap  648  provided between the second tube  634  and the third tube  644 . The third tube  644  also includes a closed end  650  defined by an end wall  649  disposed axially opposite to the third outlet  646 . The third tube  644  is connected to the second tube  634  adjacent to the closed end  642  of the second tube  634 . More specifically, the end wall  649  of the third tube  644  is connected to the wall  640  of the second tube  634  adjacent to the closed end  642  of the second tube  634 . The third outlet  646  is spaced apart from each of the second inlet  636  and the second outlet  638  of the second tube  634 . Accordingly, the second outlet  638  of the second tube  634  is axially disposed between the closed end  642  of the second tube  634  and the third outlet  646  of the third tube  644 . 
     Specifically, the one or more openings  639  are axially disposed between the closed end  642  of the second tube  634  or the closed end  650  of the third tube  644 , and the third outlet  646  of the third tube  644 . In other words, the one or more openings  639  are disposed between the closed end  642  of the second tube  634  or the closed end  650  of the third tube  644 , and the third outlet  646  of the third tube  644  relative to a longitudinal axis (not shown) of the muffler  602 . In such a situation, the reversal portion  251  of the muffler  202  is omitted. The end wall  649  of the third tube  644  may be connected to the wall  640  of the second tube  634  by various methods, such as welding, adhesives, mechanical joints, fasteners, a pin-type weld, a pipe-to-pipe joint, and so on, based on application requirements. In some embodiments, the third tube  644  may be pinched down to form the end wall  649  which is connected to the second tube  634 . 
     During operation, the second exhaust stream “E 2 ” is received into the muffler  602  from the second pipe  116  (shown in  FIG. 1 ) via the second inlet  636  of the second tube  634 . The second exhaust stream “E 2 ” is then deflected by the end wall  643  and the closed end  642  of the second tube  634  and is discharged into the third tube  644  via the second outlet  638  of the second tube  634 , as shown by an arrow  674 . Specifically, the second exhaust stream “E 2 ” flows through the one or more openings  639 . Due to the end wall  649  and the closed end  650  of the third tube  644 , the second exhaust stream “E 2 ” flows through the gap  248 , as shown by an arrow  676 . As such, the second exhaust stream “E 2 ” undergoes flow reversal upon entering the gap  248 . The second exhaust stream “E 2 ” is further discharged into the common chamber  220  via the third outlet  646  of the third tube  644 , as shown by an arrow  678 . 
     Referring to  FIGS. 3A and 3B , exemplary graphical representations of a performance of the muffler  202  in comparison to performance of a conventional muffler (not shown) are illustrated. The conventional muffler refers to a muffler without an arrangement of the second tube  234  and the third tube  244  as described with reference to the muffler  202 . 
     Referring to  FIG. 3A , a graphical representation of engine speed against one and a half (1.5) engine order noise at partially-open throttle condition is illustrated. A curve “C 1 ” represents performance of the muffler  202  at the partially-open throttle condition and a curve “C 2 ” represents performance of the conventional muffler at the partially-open throttle condition. 
     As shown, the half engine order noise reduces by approximately 15-25 decibels (dBA) between approximately 1500 rotations per minute (RPM) and 3300 RPM while employing the muffler  202  in comparison to the conventional muffler. Referring to  FIG. 3B , a graphical representation of engine speed against one and a half (1.5) engine order noise at wide-open throttle condition is illustrated. A curve “C 3 ” represents performance of the muffler  202  at the wide-open throttle condition and a curve “C 4 ” represents performance of the conventional muffler at the wide-open throttle condition. As shown, the half engine order noise reduces by approximately 10-15 dBA between approximately 1500 RPM and 3300 RPM while employing the muffler  202  in comparison to the conventional muffler. Similarly, the muffler  202  may reduce different harmonics (e.g., 3, 4.5, 6 etc.) of the half engine order noise as compared to the conventional muffler. 
     Referring to  FIGS. 4A, 4B, 4C, and 4D , different perspective views of another embodiment of a muffler  402  are illustrated. The muffler  402  will now be explained with combined reference to  FIGS. 4A to 4D . The muffler  402  has a configuration substantially similar to the configuration of the muffler  202  described with reference to  FIGS. 2A to 2E . As such, the muffler  402  includes a housing  404 , an outer shell  405 , a first end plate  410 , a second end plate  412 , a first internal plate  414 , a second internal plate  416 , and a third internal plate  418 . The muffler  402  also includes a common chamber  420 , a first chamber  422 , a second chamber  424 , and a third chamber  426 . The muffler  402  further includes a first tube  428 , a second tube  434 , a third tube  444 , and a reinforcing rod  470 . However, the muffler  402  includes a single outlet tube  454 . 
     In the illustrated embodiment, the outlet tube  454  is disposed in each of the common chamber  420 , the second chamber  424 , and the third chamber  426  extending between the second internal plate  416 , the third internal plate  418 , and the second end plate  412 . It should be noted that an arrangement, a location, and/or an orientation of the housing  404 , the outer shell  405 , the first end plate  410 , the second end plate  412 , the first internal plate  414 , the second internal plate  416 , the third internal plate  418 , the common chamber  420 , the first chamber  422 , the second chamber  424 , the third chamber  426 , the first tube  428 , the second tube  434 , the third tube  444 , and the reinforcing rod  470  of the muffler  402  are substantially similar to those of the muffler  202  described with reference to  FIGS. 2A to 2E . 
     During operation, the first tube  428  is coupled to the first pipe  114  and the second tube  434  is coupled to the second pipe  116 . Accordingly, the first exhaust stream “E 1 ” is received in the common chamber  420  of the muffler  402  from the first pipe  114  via the first tube  428 , as shown by an arrow  472 . Also, the second exhaust stream “E 2 ” is received in the second tube  434  from the second pipe  116 . The second exhaust stream “E 2 ” is deflected by the closed end  450  of the third tube  444  in the reversal portion  451 , as shown by an arrow  474 . The second exhaust stream “E 2 ” then flows along the gap  448  between each of the second tube  434  and the third tube  444 , as shown by the arrow  474 , and is received in the common chamber  420  from the third tube  444 , as shown by an arrow  478 . 
     As the second exhaust stream “E 2 ” flows through the muffler  402 , the second exhaust stream “E 2 ” travels the distance approximately equal to the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116 . More specifically, the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116  may be approximately equal to the sum of the second length “L 2 ” of the second tube  434  and the third length “L 3 ” of the third tube  444  less the first length “L 1 ” of the first tube  428 , i.e., (LP 1 −LP 2 ) may be approximately equal to [(L 2 +L 3 )−L 1 ]. As such, each of the second length “L 2 ” of the second tube  434  and the third length “L 3 ” of the third tube  444  compensates for the difference between the first pipe length “LP 1 ” of the first pipe  114  and the second pipe length “LP 2 ” of the second pipe  116 , in turn, limiting the half engine order noise downstream of the muffler  402 . The first exhaust stream “E 1 ” and the second exhaust stream “E 2 ” mix with each other in the common chamber  420  and forms a mixed exhaust stream “EM”. The outlet tube  454  is provided in fluid communication with the first tube  428  and the third tube  444  via the common chamber  420 . Accordingly, the mixed exhaust stream “EM” then flows into the outlet tube  454 , and is further discharged out of the muffler  402 , as shown by an arrow  480 . 
     In the illustrated embodiment, the outlet tube  454  includes a perforated region  466  disposed in the third chamber  426 . The perforated region  466  allows a portion of the mixed exhaust stream “EM” to flow into the third chamber  426 , in turn, limiting a pressure differential between the outlet tube  454  and the third chamber  426  and/or improving tuning of the muffler  402 . The muffler  402  also includes a first tuning tube  482  and a second tuning tube  486 . The first tuning tube  482  is disposed in the first internal plate  414  and in fluid communication with each of the common chamber  420  and the first chamber  422 . The second tuning tube  486  is disposed in the second internal plate  416  and in fluid communication with each of the common chamber  420  and the second chamber  424 . Each of the first tuning tube  482  and the second tuning tube  486  is adapted to allow flow of the mixed exhaust stream “EM” therethrough, as shown by arrows  484 ,  488 , respectively. Each of the first tuning tube  482  and the second tuning tube  486  is adapted to limit a pressure differential between each of the first chamber  422 , the common chamber  420 , and the second chamber  424 , in turn, improving tuning of the muffler  402 . 
     It should be noted that although each of the second tubes  234 ,  434 ,  634  and the third tubes  244 ,  444 ,  644  described with reference to  FIGS. 2A to 2E ,  FIGS. 4A to 4D , and  FIG. 6 , respectively, has a substantially straight configuration, in other embodiments, one or more of the second tubes  234 ,  434 ,  634  and/or the third tubes  244 ,  444 ,  644  may have any other configuration. Referring to  FIGS. 7A to 7D , different exemplary configurations of a second tube and a third tube are illustrated. For example, referring to  FIG. 7A , a second tube  734   a  has a substantially L-shaped or a single bent configuration and includes a second inlet  736   a  and a second outlet  738   a.  Also, a third tube  744   a  has a substantially straight configuration and includes a third outlet  746   a.  In another embodiment, referring to  FIG. 7B , the second tube  734   a  has the substantially L-shaped or the single bent configuration and includes the second inlet  736   a  and the second outlet  738   a.  Also, a third tube  744   b  has a substantially L-shaped or a single bent configuration and includes a third outlet  746   b.    
     In another embodiment, referring to  FIG. 7C , a second tube  734   c  has a substantially C-shaped or a double bent configuration and includes a second inlet  736   c  and a second outlet  738   c.  Also, the third tube  744   a  has the substantially straight configuration and includes the third outlet  746   a.  In yet another embodiment, referring to  FIG. 7D , the second tube  734   c  has the substantially C-shaped or the double bent configuration and includes the second inlet  736   c  and the second outlet  738   c.  Also, the third tube  744   b  has the substantially L-shaped or the single bent configuration and includes the third outlet  746   b.  It should be noted that different configurations of each of the second tubes  734   a,    734   c  and each of the third tubes  744   a,    744   b  described herein are merely exemplary and may vary based on application requirements. As such, one or more of the second tubes  734   a,    734   c  and/or the third tubes  744   a,    744   b  may have single or multiple bent configurations, curved or curvilinear configurations, and so on, based on application requirements. 
     Referring to  FIG. 5 , an exemplary schematic representation of another exhaust system  500  coupled to the engine  102  is illustrated. In the illustrated embodiment, the first pipe length “LP 1 ” of the first pipe  514  is approximately equal to the second pipe length “LP 2 ” of the second pipe  516 . Further, each of the first pipe  514  and the second pipe  516  is coupled to the muffler  112 . The muffler  112  may be any one of the muffler  202 , as described with reference to  FIGS. 2A to 2E , or the muffler  402 , as described with reference to  FIGS. 4A to 4D , or the muffler  602 , as described with reference to  FIG. 6 . In such a situation, each of the second length “L 2 ” of the second tube  234 ,  434 ,  634  and the third length “L 3 ” of the third tube  244 ,  444 ,  644  provides an increased travel distance for the second exhaust stream “E 2 ” within the muffler  112 . As such, in such a configuration, each of the second length “L 2 ” of the second tube  234 ,  434 ,  634  and the third length “L 3 ” of the third tube  244 ,  444 ,  644  increases the half engine order noise downstream of the muffler  112  and may be applicable in situations when the half engine order noise may be desired, such as in sports-oriented vehicles, vehicular applications requiring rumbling exhaust noise, and so on. 
     In other words, the sum of the second length “L 2 ” of the second tube  234 ,  434 ,  634  and the third length “L 3 ” of the third tube  244 ,  444 ,  644  is greater than the first length “L 1 ” of the first tube  228 ,  428 , i.e., (L 2 +L 3 ) is greater than (L 1 ). Accordingly, the travel length of the second exhaust stream “E 2 ” through the second pipe  516 , the second tube  234 ,  434 ,  634 , and the third tube  244 ,  444 ,  644  is greater than the travel length of the first exhaust stream “E 1 ” through the first pipe  514  and the first tube  228 ,  428  in order to increase the half engine order noise downstream of the muffler  202 ,  402 ,  602 . In such a situation, the sum of the first pipe length “LP 1 ” of the first pipe  514  and the first length “L 1 ” of the first tube  228 ,  428  is less than the sum of the second pipe length “LP 2 ” of the second pipe  516 , the second length “L 2 ” of the second tube  234 ,  434 ,  634  and the third length “L 3 ” of the third tube  244 ,  444 ,  644 , i.e., (LP 1 +L 1 ) is less than (LP 2 +L 2 +L 3 ) in order to increase the half engine order noise downstream of the muffler  202 ,  402 ,  602 . 
     The muffler  202 ,  402 ,  602  provides a simple, efficient, and cost-effective method of limiting the half engine order noise within the exhaust system  100 ,  500 . The muffler  202 ,  402 ,  602  includes the second tubes  234 ,  434 ,  634  and the third tubes  244 ,  444 ,  644  having an overlapping and concentric arrangement defining the overlap length “OL” and the reversal length “RL”, in turn, providing a compact configuration, and optimizing space utilization and tuning volume within the mufflers  202 ,  402 ,  602 . Also, each of the second length “L 2 ” of the second tubes  234 ,  434 ,  634  and the third length “L 3 ” of the third tubes  244 ,  444 ,  644  may be easily adjusted, i.e., increased or decreased, in order to tune the muffler  202 ,  402 ,  602 , based on application requirements. 
     The arrangement also reduces an overall footprint of the muffler  202 ,  402 ,  602 . The muffler  202 ,  402 ,  602  also provides improved mixing of the first exhaust stream “E 1 ” and the second exhaust stream “E 2 ” within the common chamber  220 ,  420 , in turn, improving efficiency and performance of the muffler  202 ,  402 ,  602 . In some situations, as described with reference to  FIG. 5 , the muffler  202 ,  402 ,  602  may be employed in the exhaust system  500  in order to increase the half engine order noise, based on application requirements. The muffler  202 ,  402 ,  602  may be employed in any exhaust system with little or no modification to the existing system, in turn, providing wide compatibility and usability. 
     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.