Patent ID: 6789644
Filing Date: 2004-09-14
Classification: F01N

Abstract:
An engine muffler comprising:a partition board dividing the muffler having a chamber gas inlet aperture connecting to an engine exhaust gas outlet and a chamber gas outlet aperture into a first expansion chamber and a second expansion chamber; the first expansion chamber having a chamber gas inlet aperture connecting to an engine exhaust gas outlet; the second expansion chamber having a chamber gas outlet aperture; a first exhaust gas purifier provided passing through a part of the partition board and extending between the first and the second expansion chambers; a first cover plate, which has an inlet aperture, covering an upstream portion of the first exhaust gas purifier in the first expansion chamber; an exhaust gas upstream flow-in portion formed by the partition board, the first exhaust gas purifier and the first cover plate in the first expansion chamber; a second cover plate, which has an outlet aperture, covering a downstream portion of the first exhaust gas purifier in the second expansion chamber; and an exhaust gas downstream flow-out portion formed by the partition board, the first exhaust gas purifier and the second cover plate in the second expansion chamber; wherein a wall of at least one of the first expansion chamber and the second expansion chamber has a double wall construction with a predetermined gap interposed therebetween.