Exhaust muffler

Abstract

An exhaust muffler comprises a hollow body and an exhaust pipe disposed at least partially within the hollow body. The hollow body defines a first set of apertures on the hollow body and the exhaust pipe defines a second set of apertures and a third set of apertures on the exhaust pipe. The exhaust pipe has an inner surface and an outer surface. The inner surface defines a primary exhaust gas flow path (P). At least one divider allows the exhaust pipe to pass therethrough, and divides the hollow body into a first chamber and a second chamber. The first chamber defines a reservoir fluidly associated with the primary exhaust gas flow path (P) via the second set of apertures, and to the environment via the first set of apertures. The second chamber is fluidly associated with the primary exhaust gas flow path (P) via the third set of apertures.

What is claimed is: 
     
         1 . An exhaust muffler comprising:
 a hollow body defining a first set of apertures on the hollow body,   an exhaust pipe having an inlet opening, and an outlet opening spaced apart from the inlet opening, wherein the exhaust pipe is disposed at least partially within the hollow body with the exhaust pipe having an inner surface and an outer surface disposed opposite to the inner surface,   wherein the inner surface defines a primary exhaust gas flow path (P) extending along from the inlet opening to the outlet opening, and   wherein the exhaust pipe defines a second set of apertures and a third set of apertures on the exhaust pipe such that the exhaust gases flowing through the exhaust pipe flow out of the exhaust pipe within the hollow body and/or flow back into the exhaust pipe from the hollow body through the second set of apertures and the third set of apertures, and   at least one divider defining an opening to allow the exhaust pipe to pass therethrough, wherein the at least one divider divides the hollow body into at least a first chamber and a second chamber operatively configured for sound attenuation, wherein the first chamber is engaged with the second chamber,   wherein the first chamber defines a reservoir fluidly associated with the primary exhaust gas flow path (P) via the second set of apertures, and to the environment via the first set of apertures, and   wherein the second chamber is fluidly associated with the primary exhaust gas flow path (P) via the third set of apertures.   
     
     
         2 . The exhaust muffler according to  claim 1 , wherein the second chamber is filled with an absorption material. 
     
     
         3 . The exhaust muffler according to  claim 1 , wherein the reservoir defines a reservoir volume (V) and the second set of apertures define an area (A) such that a minimum reservoir volume (V min ) to the area (A) ratio is greater than or equal to 100 mm: (100 mm<=V min /A). 
     
     
         4 . The exhaust muffler according to  claim 1 , wherein the second chamber is disposed downstream of the reservoir and on an opposite side of the divider separating the second chamber and the reservoir. 
     
     
         5 . The exhaust muffler according to  claim 2 , wherein the third set of apertures is a row of apertures at least partially surrounded by the absorption material in the second chamber. 
     
     
         6 . The exhaust muffler according to  claim 1 , wherein the first set of apertures, and/or the second set of apertures, and/or the third set of apertures have apertures of shape similar to a slot. 
     
     
         7 . The exhaust muffler according to  claim 1 , wherein the exhaust pipe has a multi-piece structure joined together by at least one divider. 
     
     
         8 . The exhaust muffler according to  claim 1 , wherein the second set of apertures is configured to attenuate low frequency standing waves, in particular ranging from 50-250 Hz. 
     
     
         9 . The exhaust muffler according to  claim 1 , wherein the second chamber is configured to attenuate high frequency air rush, in particular ranging from 500-2500 Hz. 
     
     
         10 . The exhaust muffler according to  claim 1 , wherein the at least one divider has a fourth set of apertures configured to allow fluid communication between at least two chambers.