Flattened venturi, method and apparatus for making

A muffler defining a portion of a path for exhaust gases from an internal combustion engine comprising:

• a housing;
• and
• a venturi at least partially within the housing and forming a portion of said gas path through said housing and comprising:
• a tubular sidewall defining a pair of opposing, substantially circular open ends and surrounding a centerline extending between the open ends, the venturi having at each point along the centerline and at the open ends, a transverse cross-sectional area normal to the centerline and a major axis extending between a pair of most divergent points of the sidewall in the plane of the transverse cross-sectional area;
• a first section of the sidewall near one of said open ends having transverse cross-sectional areas diminishing in magnitude and major axes increasing in magnitude as the first section extends from near said one open end towards the remaining open end;
• a second section of the sidewall near the remaining open end having transverse cross-sectional areas diminishing in magnitude and major axes increasing in magnitude as the second extends from near the remaining open end towards the one open end;
• and
• said first and second sections of the sidewall each having at least one major axis greater than the major axes at either of said open ends.

A muffler defining a portion of a path for exhaust gases from an internal combustion engine comprising:

• a housing;
• and
• a hollow tube forming a portion of the exhaust gas path through the housing and having a sidewall, a pair of opposing substantially circular open ends, a central axis between the open ends, and a transverse cross-sectional area at each point along the central axis normal to the central axes;
• a throat section of the tube between the open ends having the minimal transverse cross-sectional area of the tube;
• a first section of the tube between one open end and the throat section having two opposing sections of the sidewall diverging from the central axis as the tube extends from the one open end to the throat section;
• and
• a second section of the tube between the remaining open end and throat section having two opposing sections of the sidewall diverging from the central axis as the tube extends from the remaining open end to the throat section.