Engine exhaust recirculation

Claim 1

In an internal combustion engine, A. an inlet header for conducting a fuel-air mixture to said engine for combustion therein, B. a throttle valve for controlling the flow of said mixture to said engine, C. an exhaust header for discharging exhaust gases from said engine, D. means for effectively inhibiting the formation of oxides of nitrogen during said combustion at part open throttle conditions by limiting the combustion temperature comprising restricted bypass duct means for conducting exhaust gases from said exhaust header into said inlet header, E. exhaust reactor means in communication with said exhaust header downstream of the communication of the latter with said bypass duct means to receive exhaust gases for effecting the reaction of incompletely reacted components of said exhaust gases, and F. means for reversing the flow through said bypass duct during wide open throttle operation comprising opposite ends of said bypass duct means opening respectively into said exhaust and inlet header at predetermined locations and angular arrangements with respect to the gas flow within their respective headers to effect a higher effective pressure during said wide open throttle operation at the one end of said bypass duct means opening into said inlet header than at the opposite end of said bypass duct meAns opening into said exhaust header, thereby to reverse the flow through said bypass duct means and supply inlet gases to said exhaust header to facilitate said reaction in said reactor.