Abstract:
A muffler for an exhaust system of a gas combustion engine, which comprises a muffler body ( 14 ) connected to an exhaust pipe inlet ( 10   a ), an exhaust pipe outlet ( 11   a ) to the tailpipe connected to the muffler body ( 14 ), and adjacent baffles ( 23, 24 ) within the muffler body ( 14 ), characterized in that the exhaust pipe inlet ( 10   a ), the exhaust pipe outlet ( 11   a ) and the adjacent baffles ( 23, 24 ) are in line without significant restriction to gas exhaust flow and having baffle openings ( 21, 22 ) and baffle louver openings ( 18   b,    19   b ) to the central muffler chamber ( 17 ), whereby the central muffler chamber route ( 17 ) is generally a straight line from the exhaust inlet pipe ( 10   a ) to the exhaust pipe outlet ( 11   a ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the provisional patent application Ser. No. 61/596,088, filed 2012 Feb. 7, entitled “Muffler for Automobile”. 
    
    
     BACKGROUND 
     The present application relates to the field of exhaust mufflers and, more particularly, to automotive mufflers. Automotive mufflers are created using different methods to channel gas exhaust through exhaust pipes in order to displace and muffle engine sound. Because of their complexity, many of these methods are over-thought and over-designed resulting in restricted performance and efficiency to the engine. Most engines perform at maximum capacity when exhaust airflow is not restricted. Mufflers that contain multiple and complex baffles to channel exhaust airflow create backflow pressure to the engine causing loss of performance and efficiency. Complex baffle designs can be expensive and complicated to manufacture. Other designs use packing, which typically consists of a fiberglass material placed within the muffler to displace sound. Due to extreme temperatures produced from the engine to the muffler, packing eventually hardens and breaks down, thus creating undesirable sound and ultimately the need for replacement. 
     SUMMARY 
     In one aspect, the disclosure provides baffles permanently contained in a fixed location within the muffler body allowing for direct airflow through the muffler chamber resulting in increased performance and efficiency from the engine. Due to the simplicity of the design, the manufacturing process is simple to achieve and requires minimal labor effort to assemble. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a top partially cut away view showing an automotive muffler according to one embodiment. 
         FIG. 1B  shows a portion of another embodiment of an automotive muffler. 
         FIG. 1C  is a side view of the arrangement of  FIG. 1A . 
         FIG. 1D  is another side view of the arrangement of  FIG. 1A . 
         FIG. 2  is an isometric view of internal components of the automotive muffler of  FIG. 1A . 
         FIG. 3  is a top, partially-cut away view of another embodiment of an automotive muffler. 
         FIG. 4  is an assembled isometric view of the automotive muffler of  FIG. 3 . 
         FIG. 5  is an exploded isometric view of the automotive muffler of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A, 1C, 1D and 2  illustrate one embodiment of an automotive muffler for the exhaust system of a gas combustion engine.  FIG. 1A  is a top view of the automotive muffler, which can be made of a metal, such as steel or stainless steel. In the illustrated embodiment, the automotive muffler has a muffler casing or body  14  which includes an exhaust inlet end cap  12  and an opposing exhaust outlet end cap  13 . An outer wall  140  extends between the end caps  12 ,  13 . The end caps  12 ,  13  can be joined to opposite ends of the outer wall  140  such as by welding. In the illustrated embodiment, the muffler body  14  has an elongated, rectangular box-like structure and can have rounded longitudinal edges. A center muffler chamber  17  is formed within the muffler body  14 . 
     An exhaust pipe inlet  10   a  can be joined to the inlet end cap  12  by inserting the exhaust pipe inlet  10   a  through a hole in the inlet end cap  12  and then welded to the inlet end cap  12  via an exhaust pipe inlet flange  10   b . Similarly, an exhaust pipe outlet  11   a  is joined to the outlet end cap  13  by first inserting the exhaust pipe outlet  11   a  through a hole in the outlet end cap  13  and then welding an exhaust pipe outlet flange  11   b  to the outlet end cap  13 . The exhaust pipe inlet  10   a , the first end cap  12 , the exhaust pipe outlet  10   b , and the second end cap  13  can be made of metal. Gas exhaust can follow an exhaust flow path E entering the automotive muffler through the exhaust pipe inlet  10   a  and exiting through the exhaust pipe outlet  11   a . The exhaust pipe inlet  10   a  and the exhaust pipe outlet  11   a  can be substantially aligned along the longitudinal axis of the muffler body  14 . The exhaust flow path E can extend in a straight line from the exhaust pipe inlet  10   a  to the exhaust pipe outlet  11   a , uninterrupted by any internal structure within the muffler body  14 . 
     With continued reference to  FIGS. 1A , C &amp; D and  2 , a baffle  23  having an upstream portion and a downstream portion is enclosed within the muffler body  14 . The illustrated baffle  23  is elongated, has top and bottom surfaces, and opposite ends extending the full length of the muffler body  14 . An upstream end of the baffle  23  is attached at a first corner of the muffler body  14  where the inlet end cap  12  meets the outer wall  140 . A downstream end of the baffle is attached at a second corner of the muffler body  14  where the outlet end cap  13  meets the outer wall  140 .  FIG. 1B  shows another embodiment in which the ends of the baffle  23  are not attached to the muffler body  14  at the first and second corners, but instead are attached to the ends caps at locations spaced from the associated corner in order to fit different muffler casing designs. 
     The baffle  23  can be made of any material, such as metal, including  14  gauge steel or stainless steel. The baffle  23  preferably is attached to the muffler body  14  along the entirety of both the top and bottom surfaces, preferably by top and bottom welds that each extend the complete length of the baffle  23 . Preferably the ends of the baffle  23  are attached along their complete height, preferably by welds that extends the entire height of the ends. 
     The length of the baffle can be between 14 inches to 16 inches or any length, depending on the application and design. The height of the baffle  23  can be around 4 inches to 5 inches or any height, depending on the application and design. 
     As best shown in  FIG. 1A , the upstream portion and the downstream portion of the baffle  23  can be separated by a bend in the baffle  23 . As shown, the upstream portion extends from the upstream end cap in a direction transverse to the longitudinal axis so as to narrow the exhaust flow path E. The downstream portion extends from the bend to the downstream end cap also in a direction transverse to the longitudinal axis but oriented so as to broaden the exhaust flow path. 
     The baffle  23  cooperates with the outer wall  140  to define a sound cancelling chamber, or baffle chamber  16  within the muffler body  14 , which baffle chamber  16  is separated from the muffler chamber  17  by the baffle  23 . In the illustrated embodiment, the baffle chamber  16  is generally triangular in shape. 
     A baffle upstream sound hole or upstream aperture  22   a  is formed through the upstream portion. A downstream sound hole or aperture  22   b  is formed through the downstream portion of the baffle  23 . In the illustrated embodiment of  FIG. 1 , and as shown in  FIGS. 1C and 1D , the upstream and downstream apertures  22   a, b  are each a circular hole about 1¼ inches in diameter located approximately midway along the upstream portion and midway along the downstream portion. The location, size, shape, and number of the apertures  22   a ,  22   b  can change based on application and design. 
     With continued reference to  FIGS. 1A and 2 , the apertures  22   a ,  22   b  are designed to trap and muffle sound. Since the baffle  23  is connected along its top and bottom and at its ends, the baffle sound holes preferably are the only air pathways into and out of the sound cancelling chamber  16 . As shown, preferably a portion of the sound associated with exhaust follows a sound travel path S into the muffler chamber  17  through the inlet pipe  10   a , and then into the sound cancelling chamber  16  through the upstream baffle aperture  22   a . Sound is trapped and muffled in the chamber  16 , and exits back into the muffler chamber  17  via the downstream baffle aperture  22   b  and exits the muffler via the outlet pipe  11   a.    
     With continued reference to  FIGS. 1A , B &amp; C and  2 , a second baffle  24  that mirrors the first baffle  23  can be placed opposite the longitudinal axis of the muffler body  14 . The second baffle  24  would also have an upstream and a downstream portion, one or more upstream apertures  21   a , one or more downstream apertures  21   b , further divide the muffler chamber  17  into a smaller muffler chamber  17  and another baffle chamber  15 , and define a sound pathway S through the baffle chamber  15 . 
     In the illustrated embodiment, the muffler chamber  17  is generally hourglass-shaped, having wide portions at or adjacent the inlet and the outlet portions of the muffler body  14 . A narrowed portion of the muffler chamber  17  is defined between the bends of the baffles  23 ,  24 . Preferably the narrowed portion is substantially midway along the length of the muffler body  17  such that the upstream portions and the downstream portions of the baffles  23 ,  24  have approximately the same length. In one embodiment, the narrowed portion is about 5 inches wide, but this width can vary depending on application, baffle angle, and muffler body width. In the illustrated embodiment, the narrowed portion is the narrowest space along the length of the exhaust pathway E. 
       FIGS. 3-5  illustrate another embodiment of an automotive muffler having a casing or muffler body  14  enclosing a muffler chamber  17 . An exhaust inlet pipe  10   a  extends through an end cap  12  to deliver exhaust to the muffler chamber  17 . Exhaust exits the chamber  17  through an exhaust outlet pipe  11   a  that extends through an end cap  13 . A baffle  23  within the body  14  defines a baffle chamber  16  that is separated from the muffler chamber  17 . A baffle  24  is a mirror image of baffle  23  and defines a baffle chamber  15  that is separated from the muffler chamber  17 . As such, the muffler chamber  17  has an hourglass shape. Weld supports  20  along the longitudinal top and bottom of each baffle can be welded to the interior of the muffler body  14 . 
     The illustrated baffles  23 ,  24  each have one upstream sound hole  22 ,  21 , formed through an upstream portion of the respective baffle. Each baffle also has three downstream sound holes  19   b ,  18   b  formed through a downstream portion of each baffle, which downstream portion is defined as the part downstream along the exhaust flow path from the narrowest part of the hourglass shape. In the illustrated embodiment, the upstream sound holes  21 ,  22  are each circular, and are each located off center of the upstream portion of the baffle  23 ,  24 . More specifically, the upstream holes are located somewhat forward of the center of each upstream portion. 
     With continued reference to  FIGS. 3-5 , in the illustrated embodiment, the downstream apertures  18   b ,  19   b  are generally rectangular, and each have an adjacent latitudinal louver  18   a ,  19   a  extending from a downstream edge of the associated downstream aperture  18   b ,  19   b . In the illustrated embodiment, each louver extends in a direction away from the baffle chambers  15 ,  16  into the muffler chamber  17 . The illustrated louvers  18   a ,  19   a  are generally straight and extend in a direction transverse to the longitudinal axis. In the illustrated embodiment, the louvers  18   a ,  19   a  extends in a direction generally towards the exhaust pipe inlet  10   a . The louvers  18   a ,  19   a  can be formed by partially punching out the downstream apertures  18   b ,  19   b  and bending the louvers  18   a ,  19   a  at the downstream edge of the downstream apertures  18   b ,  19   b.    
     In accordance with one embodiment, a method for making an automotive muffler as in  FIGS. 3 and 4  is provided. In accordance with the embodiment, a metal such as steel or stainless steel is cut to create the muffler body  14 . The steel is bent longitudinally to form a uniform muffler body  14  and muffler chamber  17 . The formed muffler body  14  is then welded on the exterior of one side to create a solid muffler body  14 . The formed muffler body  14  can be sealed by creating a weld along one side of the longitudinal length of the formed muffler body  14 . Two baffles  23 ,  24  are cut out of steel or stainless steel, then bent at equal locations creating the initial stages of the baffle chambers  15 ,  16 . Baffle weld supports  20  are then bent outward toward the center of the muffler chamber  17  and welded to the muffler body  14 . The baffles  23 ,  24  can be secured to the muffler body  14  by multiple welds along the weld support locations. The baffles can also be secured to the muffler body by multiple weld locations along the inside latitudinal edge. The exhaust inlet pipe  10   a  and exhaust outlet pipe  11   a  can be joined to respective end caps  12 ,  13  by first inserting the exhaust inlet and outlet pipes  10   a ,  11   a , through hole in the associated end caps  12 ,  13  and then welding the pipes to the end caps via associated exhaust pipe flanges  10   b ,  11   b . The end caps  12 ,  13  can then be welded to the respective ends of the muffler body  14 .