Patent ID: 7503427

Claim:
A muffler comprising: a muffler body defining an expansion room; an upstream pipe, an end portion thereof is opened in the expansion room; a downstream pipe having a first straight pipe portion opened in the expansion room, a second straight pipe portion opened outside of the expansion room, and the first straight pipe portion and the second straight pipe portion being joined together by a curved pipe portion; and an opening formed in a side face of the second straight pipe portion of the downstream pipe in the expansion room, the opening being formed in an elongated area extending substantially along a main axis of the downstream pipe, wherein the end portion of the upstream pipe and an end portion of the first straight pipe portion of the downstream pipe are opened towards the same direction, wherein the opening in the downstream pipe is positioned in an axial direction only between the end portion of the upstream pipe and the end portion of the first straight pipe portion of the downstream pipe, and wherein the elongated area is directionally stretched in a circumferential direction of the downstream pipe and is evenly distributed in a substantial main axis direction of the downstream pipe.