Systems and methods for control of turbine-generator via valve deactivation in a split exhaust engine system

A method of operating an engine including a first exhaust passage directly coupled to a turbine driving a generator and a second exhaust passage directly coupled to an exhaust catalyst, an outlet of the turbine coupled to the catalyst via a third exhaust passage, the method comprising:

• determining engine operating conditions which comprise at least one of an actual turbine speed, an actual generator speed, and an actual generator output;
• in response to determining, with an engine controller, the actual turbine speed less than a threshold turbine speed,
• flowing exhaust gas produced by combustion to the turbine by operating a first exhaust valve of all cylinders, the first exhaust valve in each of said all cylinders selectively allowing the exhaust gas flow from the each of said all cylinders to the first exhaust passage via a first exhaust manifold;
• and
• flowing exhaust gas produced by combustion to the catalyst by operating a second exhaust valve of said all cylinders, the second exhaust valve in the each of said all cylinders selectively allowing the exhaust gas flow from the each of said all cylinders to the second exhaust passage via a second exhaust manifold;
• and
• in response to determining, with the engine controller, the speed of the turbine at or above the threshold speed,
• selectively deactivating the first exhaust valve of a number of cylinders while maintaining the first exhaust valve of a remaining number of the cylinders active;
• wherein the first exhaust valve of the each of said all cylinders is operated via a first actuator and the second exhaust valve of the each of said all cylinders is operated by a second actuator.

A system comprising:

• an engine cylinder;
• a first exhaust valve for delivering an initial portion of exhaust gas from the cylinder to a turbine-generator via a first exhaust passage;
• a second exhaust valve for delivering a latter portion of the exhaust gas from the cylinder to an exhaust catalyst located downstream of the turbine-generator via a second exhaust passage separate from the first exhaust passage, an outlet of the turbine-generator coupled to the exhaust catalyst via a third passage;
• a valve actuator configured to deactivate the first exhaust valve;
• and
• a controller with computer readable instructions included on a non-transitory computer readable medium to execute of:
• determining engine operating conditions which comprise at least one of an actual turbine speed, an actual generator speed, and an actual generator output;
• and
• deactivating the first exhaust valve in response to the actual generator output greater than a threshold generator output.