Exhaust gas recirculation system with high rate valve

Claim 2

An exhaust gas recirculation system for an internal combustion engine having a carburetor for air fuel supply at one end of an engine induction passage with an unrestricted segment, a throttle valve in said induction passage at the other end thereof for controlling air-fuel flow therethrough to an intake manifold in communication with combustion chambers, and an exhaust passage for exhaust gas flow from the engine comprising: an exhaust gas recirculation line connected between the exhaust passage and a point in the unrestricted segment of the induction passage upstream of said throttle valve and downstream of the carburetor, valve means for controlling exhaust gas recirculation through said recirculation line in accordance with changes in intake manifold pressure, said valve means including means responsive to intake manifold pressure for selectively opening and closing said valve means throughout a throttle position range from idle to wide open throttle, said valve means including a variable geometry flow path therethrough scheduled to open so as to produce a ratio of exhaust gas recirculation to inlet air flow which continually increases as engine load increases thereby to maximize the exhaust gas recirculation to a point slightly less than will produce misfire in the combustion chambers because of charge dilution of the air fuel charge by recirculation of exhaust gas from the exhaust passage to the induction passage.

Claim 5

An exhaust gas recirculation control system for use in an internal combustion engine having a carburetor at one end of an induction passage with an unrestricted segment for air flow to the engine, a throttle in the other end of said induction passage controlling air flow therethrough to produce a quantity of air-fuel mixture proportional to engine load and speed, and a combustion chamber along with an exhaust passage for exhaust gas flow from the engine comprising: means defining an exhaust gas recirculation introduction port in the unrestricted segment of the induction passage between the carburetor and engine throttle valve, an exhaust gas recirculation line connected between the exhaust passage and the introduction port, valve means in said exhaust gas recirculation line movable between closed and opened positions for controlling exhaust gas recirculation flow, said valve means having an opening therein contoured to progressivEly increase valve flow area at a continuously positive rate from said closed position to said open position with the positive rate being greatest at the initial opening movement and least at the final opening movement, a valve operator including a movable diaphragm and housing means forming an enclosure, a vacuum signal line connected between the intake manifold of the engine and the enclosure for biasing said diaphragm in accordance with changes in intake manifold pressure produced by increases in engine load, spring means within said enclosure for opposing the biasing action of said vacuum signal, actuator means coupling said diaphragm to said valve means for causing said valve means opening to progressively move into a more open position in accordance with engine load to continually increase the ratio of exhaust gas recirculation flow to air flow through the induction passage as engine load increases through a throttle range from throttle idle operation to wide open throttle operation, said spring means returning said valve means to full open position upon vacuum signal failure to produce maximum exhaust gas recirculation at reduced engine loads thereby to reduce engine performance so as to indicate system malfunction.

Claim 6

An exhaust gas recirculation control system for use in an internal combustion engine having a carburetor at one end of an induction passage with an unrestricted segment for air flow to the engine, a throttle in the other end of said induction passage controlling air flow therethrough to produce a quantity of air-fuel mixture proportional to engine load and speed, and a combustion chamber along with an exhaust passage for exhaust gas flow from the engine comprising: means defining an exhaust gas recirculation introduction port in the unrestricted segment of the induction passage between the carburetor and engine throttle valve, an exhaust gas recirculation line connected between the exhaust passage and the introduction port, valve means in said exhaust gas recirculation line movable between closed and opened positions for controlling exhaust gas recirculation flow, said valve means having an opening therein contoured to progressivEly increase valve flow area at a continuously positive rate from said closed position to said open position with the positive rate being greatest at the initial opening movement and least at the final opening movement, a valve operator including a movable diaphragm and housing means forming an enclosure, a vacuum signal line connected between the intake manifold of the engine and the enclosure for biasing said diaphragm in accordance with changes in intake manifold pressure produced by increases in engine load, spring means within said enclosure for opposing the biasing action of said vacuum signal, actuator means coupling said diaphragm to said valve means for causing said valve means opening to progressively move into a more open position in accordance with engine load to continually increase the ratio of exhaust gas recirculation flow to air flow through the induction passage as engine load increases through a throttle range from throttle idle operation to wide open throttle operation, said spring means returning said valve means to full open position upon vacuum signal failure to produce maximum exhaust gas recirculation at reduced engine loads thereby to reduce engine performance so as to indicate system malfunction.