Ignition and Knock Tolerance in Internal Combustion Engine by Controlling EGR Composition

A method of operating an internal combustion engine, the engine having an intake manifold and having multiple cylinders, comprising:

• operating at least one cylinder of the engine as a an exhaust gas recirculation (EGR) cylinder, such that the exhaust from the at least one EGR cylinder is completely recirculated to the intake manifold;
• providing the engine with an exhaust gas recirculation loop in which recirculated exhaust flows from the at least one dedicated EGR cylinder into the intake manifold without fluid communication to the exhaust exiting the engine;
• wherein the recirculated exhaust is combined with fresh intake air prior to entering the cylinders;
• operating the at least one EGR cylinder at a different air-fuel ratio than the non EGR cylinders;
• controlling the composition of the recirculated exhaust by controlling the air-fuel ratio provided to the at least one EGR cylinder;
• wherein the step of controlling the composition is performed to produce exhaust gas from the at least one dedicated EGR cylinder having a concentration of hydrogen or carbon monoxide or both, the concentration predetermined to provide a desired ignition timing of the remaining (non dedicated) cylinders.

A method of operating an internal combustion engine, the engine having an intake manifold and having multiple cylinders, comprising:

• operating at least one cylinder of the engine as a an exhaust gas recirculation (EGR) cylinder, such that the exhaust from the at least one EGR cylinder is completely recirculated to the intake manifold;
• providing the engine with an exhaust gas recirculation loop in which recirculated exhaust flows from the at least one dedicated EGR cylinder into the intake manifold without fluid communication to the exhaust exiting the engine;
• wherein the recirculated exhaust is combined with fresh intake air prior to entering the cylinders;
• operating the at least one EGR cylinder at a different air-fuel ratio than the non EGR cylinders;
• controlling the composition of the recirculated exhaust by controlling the air-fuel ratio provided to the at least one EGR cylinder;
• wherein the step of controlling the composition is performed to produce exhaust gas from the at least one dedicated EGR cylinder having a composition predetermined to provide a desired increase in anti-knock properties.