Means for accelerating the discharge of exhaust gas from an internal combustion engine

Claim 1

Means for accelerating the discharge of exhaust gas from an internal combustion engine comprising: a tubular member (1) adapted to be communicatingly connected to an engine exhaust pipe (6) and having a first tubular portion (1A) of which diameter is gradually widened in the exhaust gas flow direction along the axial direction of said tubular member (1), a second tubular portion (1B) gradually tapering in the exhaust gas flow direction and a trumpet-shape tubular portion (1C) of which diameter is suddenly widened from the smallest diameter portion of said second tubular portion (1B); and a plurality of circumferentially disposed spiral blades (2) made of thin plate for spirally flowing and guiding exhaust gas and defining a space adjacent the axial center of said tubular member (1), said spiral blade (2) disposed in said tubular member (1) between said first tubular portion (1A) and said second tubular portion (1B) thereof, each of said spiral blades (2) having an arcuate or substantially arcuate section in the widthwise direction of the spiral blade plate at right angle to the spiral direction thereof, each of said spiral blades (2) having, at that part of its inner edge located at the slightly upstream side of exhaust gas flow with respect to the largest portion of said first tubular portion (1A), a tongue piece (2a) for guiding exhaust gas flowing toward said part, to the exhaust gas downstream side in the radially external direction of said tubular member (1), each of said spiral blades (2) further having, at its end adjacent to the smallest diameter portion of said second tubular portion (1B), a steeply inclined tongue piece (2c) for imparting a rapid swirling force to spirally flowing exhaust gas, thereby to guide the exhaust gas into said trumpet-shape tubular portion (1C).