Exhaust muffler

Abstract

An exhaust muffler for an internal combustion engine, the exhaust muffler including a housing having a first end plate and a second end plate. The second end plate is disposed opposite to the first end plate. The exhaust muffler also includes an inlet pipe connected to the first end plate and an outlet pipe connected to the second end plate of the housing. A plurality of passages are disposed within the housing along a longitudinal axis of the housing, the plurality of passages have different lengths.

1 . An exhaust muffler for an internal combustion engine, the exhaust muffler comprising:
 a housing having a first end plate and a second end plate, the second end plate disposed opposite to the first end plate, wherein a perforated sheet having a plurality of openings is attached adjacent to at least one of the first end plate and the second end plate;   an inlet pipe connected to the first end plate;   a plurality of passages disposed within the housing along a longitudinal axis of the housing, the plurality of passages have different lengths; and   an outlet pipe connected to the second end plate of the housing.   
     
     
         2 . The exhaust muffler of  claim 1 , wherein the plurality of passages includes tubes. 
     
     
         3 . The exhaust muffler of  claim 2 , wherein the tubes include a bell-mouth shaped entry portion and a bell-mouth shaped exit portion. 
     
     
         4 . The exhaust muffler of  claim 3 , wherein the tubes further include an inner surface, an outer surface, and a layer of sound absorbing material disposed between the inner surface and the outer surface. 
     
     
         5 . The exhaust muffler of  claim 4 , wherein the inner surface is made of perforated sheet having about 25% to 40% open area. 
     
     
         6 . The exhaust muffler of  claim 4 , wherein the tubes further include an inlet portion adjacent to the bell-mouth shaped entry portion. 
     
     
         7 . The exhaust muffler of  claim 6 , wherein the inlet portion is made of a perforated sheet having about 25% to 40% open area. 
     
     
         8 . The exhaust muffler of  claim 1  further including a first resonator chamber defined by the first end plate and an intermediate plate. 
     
     
         9 . The exhaust muffler of  claim 8 , wherein the inlet pipe includes a tubular body portion offset from the longitudinal axis and having an intermediate opening positioned within the first resonator chamber. 
     
     
         10 . The exhaust muffler of  claim 8 , wherein the inlet pipe includes a perforated portion extending into the housing. 
     
     
         11 . The exhaust muffler of  claim 1  further including a second resonator chamber disposed within the housing, the second resonator chamber is defined by a first side wall and a second side wall. 
     
     
         12 . The exhaust muffler of  claim 11 , wherein the passages are supported by the first side wall and the second side wall. 
     
     
         13 . The exhaust muffler of  claim 11 , wherein the second resonator chamber includes an opening. 
     
     
         14 . (canceled) 
     
     
         15 . An exhaust muffler for an internal combustion engine, the exhaust muffler comprising:
 a housing having a first end plate and a second end plate, the second end plate disposed opposite to the first end plate, wherein a perforated sheet having a plurality of openings is attached adjacent to at least one of the first end plate and the second end plate;   a first resonator chamber defined by the first end plate and an intermediate plate;   an inlet pipe connected to the first end plate, the inlet pipe includes a tubular body portion having an intermediate opening positioned within the first resonator chamber;   a second resonator chamber disposed within the housing, the second resonator chamber is defined by a first side wall and a second side wall;   a plurality of passages disposed within the housing along a longitudinal axis of the housing, the plurality of passages supported by the first side wall and the second side wall and have different lengths; and   an outlet tube connected to the second end plate of the housing.   
     
     
         16 . The exhaust muffler of  claim 15 , wherein the plurality of passages includes tubes having a bell-mouth shaped entry portion and a bell-mouth shaped exit portion. 
     
     
         17 . The exhaust muffler of  claim 16 , wherein the tubes further include an inner surface, an outer surface, and a layer of sound absorbing material disposed between the inner surface and the outer surface. 
     
     
         18 . The exhaust muffler of  claim 17 , wherein the inner surface is made of perforated sheet having about 25% to 40% open area. 
     
     
         19 . The exhaust muffler of  claim 18 , wherein the tubes further include an inlet portion adjacent to the bell-mouth shaped entry portion, the inlet portion is made of a perforated sheet having about 25% to 40% open area. 
     
     
         20 . The exhaust muffler of  claim 15 , wherein the inlet pipe includes a perforated portion extending into the housing. 
     
     
         21 . The exhaust muffler of  claim 1 , wherein the perforated sheet attached to at least one of the first end plate and the second end plate includes about 25% to 40% open area.