Muffler

Abstract

A muffler for a small two-cycle engine includes: a muffler body having an expansion chamber; an exhaust-gas guide member covering an outlet for exhaust gas, the outlet being provided on the muffler body and a cover hood that covers a discharge port for exhaust gas, the discharge port being provided on the exhaust-gas guide member. A guide that guides the exhaust gas in the exhaust-gas guide member is gradually widened toward a top surface of the cover hood as proceeding to the discharge port.

1 . A muffler comprising:
 a muffler body having an expansion chamber;   an exhaust-gas guide member covering an outlet for exhaust gas, the outlet being provided on the muffler body; and   a cover hood that covers a discharge port for the exhaust gas, the discharge port being provided on the exhaust-gas guide member, and wherein:   a guide that guides the exhaust gas in the exhaust-gas guide member is gradually widened toward a top surface of the cover hood as proceeding to the discharge port.   
   
   
       2 . A muffler comprising:
 a muffler body having an expansion chamber;   an exhaust-gas guide member covering an outlet for exhaust gas, the outlet being provided on the muffler body; and   a cover hood that covers a discharge port for the exhaust gas, the discharge port being provided on the exhaust-gas guide member, and wherein:   a distance between a center of the outlet and the discharge port is less than or equal to a height of an opening portion of the discharge port.   
   
   
       3 . A muffler comprising:
 a muffler body having an expansion chamber;   an exhaust-gas guide member covering an outlet for exhaust gas, the outlet being provided on the muffler body;   a cover hood that covers a discharge port for the exhaust gas, the discharge port being provided on the exhaust-gas guide member; and   a tail pipe mounted on the outlet in the expansion chamber, and wherein:   a height of an opening portion of the discharge port is less than or equal to an inner diameter of the tail pipe.   
   
   
       4 . The muffler according to  claim 1 , wherein:
 the cover hood is provided with an outer-air mixing portion in which exhaust gas discharged from the discharge port and outer air introduced from an outside are mixed, and   an opening area of the narrowest portion of a diameter-reduced portion provided in the outer-air mixing portion in a cross section crossing a flow direction of exhaust gas is four or more times larger than an opening area of the discharge port.   
   
   
       5 . The muffler according to  claim 1 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.   
   
   
       6 . The muffler according to  claim 2 , wherein:
 the cover hood is provided with an outer-air mixing portion in which exhaust gas discharged from the discharge port and outer air introduced from an outside are mixed, and   an opening area of the narrowest portion of a diameter-reduced portion provided in the outer-air mixing portion in a cross section crossing a flow direction of exhaust gas is four or more times larger than an opening area of the discharge port.   
   
   
       7 . The muffler according to  claim 6 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.   
   
   
       8 . The muffler according to  claim 3 , wherein:
 the cover hood is provided with an outer-air mixing portion in which exhaust gas discharged from the discharge port and outer air introduced from an outside are mixed, and   an opening area of the narrowest portion of a diameter-reduced portion provided in the outer-air mixing portion in a cross section crossing a flow direction of exhaust gas is four or more times larger than an opening area of the discharge port.   
   
   
       9 . The muffler according to  claim 8 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.   
   
   
       10 . The muffler according to  claim 2 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.   
   
   
       11 . The muffler according to  claim 3 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.   
   
   
       12 . The muffler according to  claim 4 , wherein:
 a protrusion is provided adjacent to an exhaust port of the cover hood, the protrusion being protruding toward a center of the exhaust port in an in-plane direction.