Low backpressure straight-through reactive and dissipative muffler

A muffler, comprising:

• a tubular member for passing exhaust gases extending longitudinally between opposite ends and having an imperforate end portion and a perforate central portion;
• imperforate first and second end plates mounted to and extending radially from said tubular member;
• a cylindrical outer shell mounted to said end plates so as to define a muffling chamber around and between the ends of said tubular member;
• a perforate end plate disposed interiorly of said shell between said imperforate end plates, said perforate end plate being connected to said tubular member and to said outer shell and extending generally radially therebetween so as to define an annular end chamber between said perforate end plate and said first end plate and providing the sole means for communicating exhaust gases from the perforate central portion of said tubular member into said annular end chamber,
• sound absorbing material disposed in and substantially filling the annular end chamber defined between the perforate and imperforate end plates and radially between the shell and the imperforate end portion of the tubular member;
• and
• sound absorbing means completely surrounding and engaging the perforate central portion of said tubular member, said sound-absorbing means substantially filling an annulus formed between the tubular member and the inner wall of said outer sleeve except for a small annular air chamber formed between the inner wall of said outer shell and the sound absorbing means.

A muffler for silencing exhaust gases, comprising:

• a straight-through exhaust gas flow tube having imperforate inlet and outlet end portions and a perforate central portion located between said end portions;
• an outer shell having a pair of imperforate endwalls extending radially between said flow tube and said outer shell;
• an inner sound absorbing chamber comprising sound absorbing material surrounding the perforate central portion of said flow tube;
• an outer resonating chamber enclosing said inner sound absorbing chamber;
• a perforate header extending radially between said flow tube and said outer shell, said header and one of said end walls forming an annular end chamber around one of said imperforate end portions;
• a sound absorbing material extending between the header and said one end wall and radially between said shell and said one perforate end portion and substantially filling said annular end chamber,
• said perforate header being provided with a plurality of apertures to pass exhaust gases from said inner sound absorbing chamber into said annular end chamber.

A muffler for silencing exhaust gases, comprising

• a main straight-through sound conducting tube for passing exhaust gases between an inlet and an outlet end of the tube,
• a shell having spaced end walls and forming a muffling chamber around said tube, said tube including a first and second imperforate end portion adjacent, respectively, to said inlet end and to said outlet end and a perforate central portion between said imperforate end portions for communicating exhaust gases into said muffling chamber,
• first pervious sound absorbing material encircling said perforate central portion,
• a header extending between the tube and the shell for defining an annular end chamber encircling one said imperforate end portion,
• passage means in said header for communicating sound waves from said sound conducting tube into said annular end chamber, and
• second pervious sound absorbing material, extending longitudinally between one end wall of the shell and the header and radially between the shell and the one imperforate end portion of the sound conducting tube and substantially filling said annular end chamber, for silencing said sound waves.