Muffler for internal combustion engine

A muffler for an internal combustion engine having an exhaust port, the muffler comprising:

• an expansion chamber into which exhaust gas is to be introduced from the exhaust port of the internal combustion engine, the expansion chamber having at least two impingement openings for enabling the exhaust gas to be divided into at least two exhaust gas flows and enabling the divided exhaust gas flows to be subsequently impinged against each other, wherein the expansion chamber comprises a first expansion chamber into which the exhaust gas is directly introduced from the exhaust port, and a second expansion chamber which is disposed next to and on the outer peripheral side of the first expansion chamber into which the exhaust gas is directly introduced via at least one blow-off port from the first expansion chamber, the second expansion chamber being provided with the impingement openings;
• a final exhaust port for discharging the exhaust gas flows to the external atmosphere;
• and
• a collision chamber which includes the final exhaust port and covers the impingement openings.