Exhaust recycle to carburetor of an internal combustion engine

Claim 1

In an internal combustion engine having an exhaust manifold, and a float-controlled down-draft carburetor including a booster venturi means for injecting gasoline into the carburetor wherein said booster venturi is positioned above the throttle plate of the carburetor, the improvement comprising, (a) an attenuator means which places said exhaust manifold in unvalved but restricted open fluid communication with said exhaust manifold, said attenuator means comprising, (i) an attenuator chamber, and (ii) baffle means within said chamber to attenuate the velocity and lower the pressure of exhaust gases in said exhaust manifold, (b) intake conduit means of predetermined diameter to place said chamber in open fluid communication with said exhaust manifold, and, (c) supply conduit means of predetermined diameter placing said chamber in open fluid communication with said carburetor, the outlet of said supply conduit being positioned directly laterally opposite from said booster venturi so as to heat it by directly impinging recycled exhaust gases thereupon, the amount of said recycled gases to the carburetor being greater than 2 percent but less than 10 percent by volume of exhaust gases generated by said engine.

Claim 7

A method of controlling operation of an internal combustion engine by controlling the temperature of gasoline sprayed into the main venturi of a carburetor having a booster venturi, and controlling the amount of exhaust gases recycled to the carburetor, comprising, (a) conducting a self-regulated slipstream of said exhaust gases, in an amount from about 2% to 10% by volume of the exhaust gases generated by said engine, to said carburetor which is disposed in unvalved but restricted open fluid communication with an exhaust manifold of said engine, so that the pressure of said slipstream adjacent the carburetor is at least 70% of the pressure in said exhaust manifold when the engine is operating in the range from about 550-850 rpm, (b) directly heating said booster venturi by impinging said self-regulated slipstream at the center of said booster venturi, so as to maintain the temperature of the gasoline vapor flowing into said main venturi at a temperature in the range from about 200° F. to about 650° F., and (c) diluting the air flowing through said carburetor with said slipstream so as to maintain the exhaust emissions of said engine within predetermined limits.

Claim 8

A method of controlling operation of an internal combustion engine by controlling the temperature of gasoline sprayed into the main venturi of a carburetor having a booster venturi, and controlling the amount of exhaust gases recycled to the carburetor, comprising, (a) conducting a self-regulated slipstream of said exhaust gases, in an amount from about 2% to 10% by volume of the exhaust gases generated by said engine, to said carburetor which is disposed in unvalved but restricted open fluid communication with an exhaust manifold of said engine, so that the pressure of said slipstream adjacent the carburetor is at least 70% of the pressure in said exhaust manifold when the engine is operating in the range from about 550-850 rpm, (b) directly heating said booster venturi by impinging said self-regulated slipstream at the center of said booster venturi, so as to maintain the temperature of the gasoline vapor flowing into said main venturi at a temperature in the range from about 200° F. to about 650° F., and (c) diluting the air flowing through said carburetor with said slipstream so as to maintain the exhaust emissions of said engine within predetermined limits.