Patent ID: 7571789

Claim:
A muffler for exhaust systems of vehicles, comprising a tubular shell that is internally lined with a noise-deadening material and is closed at its ends by a front wall provided with an inlet connectable to receive exhaust gas, and by a rear wall, a first chamber and a second chamber being defined within the tubular shell, which are separated by a transverse wall having an inlet opening and an outlet opening, a perforated inlet pipe extending within the first chamber from the inlet to the inlet opening, gas-piping means extending within the first chamber and having one end open to said outlet opening, and the other end connectable to exhaust pipes, wherein said inlet opening and outlet opening are substantially equal in diameter to the inlet pipe, and are connected to each other via a toroidal duct that is arranged within the second chamber and is substantially equal in diameter to the inlet pipe; and wherein said gas-piping means comprise a pair of perforated pipes having two converging ends welded to said outlet opening and in mutual contact along respective flattened surfaces, so that their profile at said transverse wall substantially matches with the profile of the outlet opening.