Thermal reactor having collector therein to mix pulsed flows of exhaust and secondary air

Claim 1

An exhaust gas purification system for internal combustion engines comprising at least two cylinders including two exhaust gas passages, respectively, defining open ends, respectively, each of said exhaust gas passages including an exhaust pipe and an exhaust port and an exhaust valve communicating respectively with one another, each of said exhaust gas passages being formed with a substantially constant cross-section up to and including said open ends, in which a mass of exhaust gases passes without mixing with a subsequent mass of secondary air, a thermal reactor having a reaction chamber operatively communicating with said exhaust pipes, said exhaust pipes of said two exhaust gas passages being inserted into said reaction chamber spaced apart in parallel, heat insulating means in said exhaust gas passages for maintaining the temperature of said exhaust gases above a trigger temperature of said thermal reactor, a secondary air passage including a check valve communicating with said exhaust gas passages, respectively, providing the mass of secondary air into each of said exhaust pipes, respectively, a collecting means simultaneously communicating with said open ends of both said exhaust pipes, said collecting means defining a mixing zone and an outlet therefrom, said mixing zone having an entrance portion adjacent said open ends of said exhaust pipes and at least a central portion adjacent said entrance portion, said central portion and said entrance portion having a cross-section substantially equal to the sum of the cross-sections of both of said exhaust pipes, said collecting means for collecting the mass of exhaust gases and the mass of secondary air ejected from said exhaust pipes at said open ends, respectively, in said mixing zone, said collecting means and said mixing zone being formed so as to cause collision and diffusion of the mass of the exhaust gases and the mass of the secondary air, respectively, thereby effecting mixing thereof, said mixing zone including an outlet portion of bulge shape forming said outlet therein, said outlet defining a narrowmost portion of said collecting means and defining a radius of curvative smaller than an adjacent portion of said mixing zone, and said collecting means being disposed in said reaction chamber of said thermal reactor and having said outlet communicating therewith and for discharging a mixture of said exhaust gases and said secondary air from said outlet into said reaction chamber of said thermal reactor.