Techniques for improving fuel economy in dedicated egr engines

A method of operating an electronic control system to improve fuel economy of a dedicated exhaust gas recirculation (EGR) internal combustion engine, the method comprising:

• evaluating an operating point including an engine speed and an engine load of the dedicated EGR internal combustion engine relative to an engine operating map including an engine speed axis and an engine load axis, the engine operating map including a first zone corresponding to rich fueling of the one or more dedicated EGR cylinders of the dedicated EGR internal combustion engine, a second zone corresponding to stoichiometric fueling or lean fueling of the one or more dedicated EGR cylinders, and a third zone corresponding to zero fueling of the one or more dedicated EGR cylinders;
• if the operating point is in the first zone, operating the electronic control system to provide rich fueling of the one or more dedicated EGR cylinders;
• if the operating point is in the second zone, operating the electronic control system to provide fueling of the one or more dedicated EGR cylinders ranging from stoichiometric fueling to lean fueling;
• if the operating point is in the third zone, operating the electronic control system to provide no fueling of the one or more dedicated EGR cylinders.

A method of operating an electronic control system to improve fuel economy of a dedicated exhaust gas recirculation (EGR) internal combustion engine, the method comprising:

• fueling a plurality of cylinders of the dedicated EGR internal combustion engine, the plurality of cylinders including at least one dedicated EGR cylinder configured to provide EGR to the dedicated EGR internal combustion engine via an EGR loop, the plurality of cylinders further including at least one non-dedicated cylinder;
• evaluating an engine load and an engine speed during operation of the dedicated EGR internal combustion engine to control fueling of the at least one dedicated EGR cylinder and the at least one non-dedicated cylinder;
• and
• in response to a variation in the engine load and the engine speed, varying the fueling in the at least one dedicated EGR cylinder to differ from the fueling of the non-dedicated cylinder so that the at least one non-dedicated cylinder provides one of rich of stoichiometric combustion, stoichiometric combustion, lean of stoichiometric combustion, or zero combustion depending on the engine load and the engine speed.