Patent ID: 8002081
Filing Date: 2011-08-23
Classification: F01N

Abstract:
1. An exhaust system for a combustion engine, which comprises: a tubular inner shell for passage therethrough of exhaust gases from the combustion engine, the tubular inner shell having upstream and downstream portions opposite to each other with respect to the direction of flow of the exhaust gases from the combustion engine; a tubular outer shell enclosing the tubular inner shell and cooperating with the tubular inner shell to define a sound silencing chamber between the tubular inner shell and the tubular outer shell for receiving the exhaust gases therein; a perforated wall area defined in the upstream portion of the tubular inner shell and having a plurality of communication perforations defined therein for communicating between an interior of the tubular inner shell and the sound silencing chamber; a non-perforated wall area defined in the downstream portion of the tubular inner shell and having no communicating perforation defined therein, the non-perforated wall area and the perforated wall area being formed on the same tubular inner shell formed by a unitary tube; and an exhaust gas pressure regulating member that is tapered in a direction upstream thereof with respect to the direction of flow of the exhaust gases, the exhaust gas pressure regulating member being fixedly disposed inside the non-perforated wall area of the tubular inner shell; wherein the sound silencing chamber is positioned radially outwardly of the perforated wall area and the non-perforated wall area and is in fluid communication only with the interior of the tubular inner shell through the communication perforations, and wherein the non-perforated wall area of the tubular inner shell has an axial length with respect to the direction of flow of the exhaust gases, which is equal to or greater than 1.3 times the inner diameter of the non-perforated wall area, and which is within the range of 0.20 to 0.90 times the axial length of the perforated wall area.