Internal Combustion Engine Having Dedicated EGR Cylinder(s) With Intake Separate From Intake Of Main Cylinders

An exhaust gas recirculation (EGR) system for improved combustion efficiency of an internal combustion engine having a number of cylinders, comprising:

• one or more cylinders operable as dedicated EGR cylinder(s), such that all of its exhaust, during all or some engine cycles, may be recirculated via an EGR loop;
• one or more cylinders operable as main cylinders that receive EGR via the EGR loop and receive fresh air via a second fresh air intake line;
• an EGR loop for recirculating EGR from the dedicated EGR cylinder(s) to the engine's intake manifold;
• a mixed input line for delivering a mixture of fresh air and EGR gas to the intake of the main cylinders;
• a passage between the mixed input line and the intake line to the dedicated EGR cylinder, operable to deliver a portion of the mixture of fresh air and EGR to the dedicated EGR cylinder(s);
• wherein the dedicated EGR cylinder(s) may receive an intake comprising all fresh air or all the mixture or some proportion of both;
• a control unit programmed to perform the following tasks:
• receive data representing engine operating conditions, determine a desired EGR rate of EGR to be delivered to the main cylinders, and based on the desired EGR air, to control whether the dedicated EGR cylinder(s) receive all fresh air or all the mixture or some proportion of both.