Abstract: An exhaust gas control system has a guiding pipe with a proximal inlet end for connecting to a distal end of an engine exhaust pipe. An expanding portion of the guiding pipe has a central rearward expanding cone and spiralling blades extending between the cone and the walls of the expanding portion. The expanding portion is followed by an axially decreasing chamber and then an axially increasing chamber to the distal opening. A duct is supported on radial vanes around the latter chambers. The duct has a forward opening slightly rearward of a maximum cross-sectional dimension of the guiding pipe and has an outlet positioned rearward of the distal opening of the guiding pipe.

Abstract: An exhaust gas control system has a proximal end for connection to a distal end of an exhaust pipe and has a first divergent and convergent and second divergent portions. Curved spiralling blades extend around inner walls of the first divergent and convergent portions leaving an open central space about which exhaust gas whirls. The second divergent portion exhausts the swirling gas through a distal opening. A duct surrounds the convergent and second divergent portions and controls flow of ambient air over those portions.