Transient control of exhaust gas recirculation systems through mixer control valves

A method, comprising:

• operating an engine having a plurality of cylinders;
• directing a charge flow into the plurality of cylinders from an air intake system;
• combusting a mixture of the charge flow and fuel within the plurality of cylinders to generate a power output and a flow of exhaust;
• directing a first portion of the flow of the exhaust from a first portion of the plurality of cylinders to an aftertreatment system;
• directing a second portion of the flow of the exhaust from a second portion of the plurality of cylinders to an accumulator in an exhaust gas recirculation (EGR)system connected to the air intake system, the accumulator extending between an inlet to the accumulator and a plurality of outlets connected to the air intake system, wherein the accumulator stores a supply of recirculated exhaust gas for release into the air intake system through the plurality of outlets, wherein the accumulator includes a storage volume between the inlet and the plurality of outlets, and the storage volume is sized as a function of a total number of the plurality of cylinders contributing to the second portion of the flow of exhaust to mix with air in the air intake system;
• and
• selectively increasing or decreasing the supply of stored recirculated exhaust gas in the accumulator in response to a deviation of an EGR flow from an expected EGR fraction by controlling an opening size of one or more of the plurality of outlets into the air intake system.

A system, comprising:

• an engine including a plurality of cylinders;
• an intake passage configured to direct a charge flow to the plurality of cylinders;
• an exhaust passage configured to receive exhaust from a first portion of the plurality of cylinders and direct the exhaust from the first portion of the plurality of cylinders to an aftertreatment system;
• and
• an exhaust gas recirculation (EGR) system configured to receive exhaust from a second portion of the plurality of cylinders and direct the exhaust from the second portion to the intake passage, wherein the EGR system includes an accumulator having an inlet for receiving the exhaust from the second portion of the plurality of cylinders, a plurality of outlets along the intake passage that directly connects the accumulator to the intake passage, and a storage volume between the inlet and the plurality of outlets, wherein each of the plurality of outlets includes a flow control member operable to selectively open and close the respective outlet to permit passage of the exhaust therethrough into the intake passage, wherein the storage volume is sized as a function of a total number of the plurality of cylinders contributing to the second portion of the flow of exhaust to mix with air in the air intake system.

A system, comprising:

• a combustion engine having a first group of cylinders and a second group of cylinders, wherein the first group of cylinders and the second group of cylinders each includes at least one cylinder;
• an exhaust manifold configured to receive exhaust from the first group of cylinders;
• an aftertreatment system configured to receive exhaust from the exhaust manifold;
• an intake system configured to receive a fresh air flow and direct a charge flow to the first and second groups of cylinders;
• an exhaust gas recirculation (EGR) system configured to receive exhaust from the second group of cylinders and provide an EGR flow to the fresh air flow in the intake system and form the charge flow;
• an accumulator connecting the exhaust gas recirculation system to the intake system, the accumulator including an inlet and a plurality of separate exhaust outlets in flow communication with the intake system, wherein each of the plurality of exhaust outlets includes a flow control member that is movable between an open position and a closed position to control an amount of EGR flow that is supplied to the intake system;
• and
• a controller configured to interpret an EGR fraction deviation condition in response to an EGR flow produced by the second group of cylinders deviating from an expected EGR fraction from the second group of cylinders, wherein the expected EGR fraction is a ratio of a number of cylinders in the second group to a number of cylinders in the first group, and further wherein the controller is further configured to move at least one of the flow control members between the open and closed positions in response to the EGR fraction deviation condition to control the amount of EGR flow to the intake system.