EGR Recirculation at low load in internal combustion engines

Claim 1

In an internal combustion engine having a variable volume chamber in which combustion occurs, a main intake passage communicating with said chamber through a main intake port for delivering a charge thereto, an exhaust passage communicating with said chamber for receiving a burned charge exhausted therefrom, and an emission system for discharging exhaust gas from said exhaust passage for further treatment by combustion within said chamber, the improvement comprising an auxiliary intake passage having an inlet communicating with said main intake passage and an outlet communicating with said chamber through auxiliary port means, said auxiliary intake passage having an effective cross-sectional area substantially less than the effective cross-sectional area of said main intake passage for causing a given mass flow of charge through said auxiliary intake port to enter said chamber at a significantly greater velocity, throttle valve means for controlling the ratio of flow into said chamber through said main intake port to the flow into said chamber through said auxiliary intake port means, and means for delivering exhaust gases from said emission system to said main intake passage in a location to minimize the effects of pulsation thereof and for introduction at a high velocity into said chamber through said auxiliary intake port means under the control of said throttle valve means.