Systems and methods for a split exhaust engine system

A method, comprising:

• during a first mode, adjusting a flow of exhaust gas from a first set of cylinder exhaust valves to an intake passage via an exhaust gas recirculation (EGR) passage via adjusting each of a position of an EGR valve disposed in the EGR passage via a valve actuator and a timing of the first set of cylinder exhaust valves via a timing actuator responsive to sensed flow in the EGR passage;
• during a second mode, adjusting the flow of exhaust gas via adjusting only the position of the EGR valve;
• during a third mode, adjusting the flow of exhaust gas via adjusting only the timing of the first set of cylinder exhaust valves;
• and
• selecting between the first, second, and third modes based on a difference between a measured pressure drop and an expected pressure drop across the EGR valve.

A system, comprising:

• a first exhaust manifold coupled to a first set of cylinder exhaust valves and an exhaust passage including a turbine;
• a second exhaust manifold coupled to a second set of cylinder exhaust valves;
• an exhaust gas recirculation (EGR) passage including an EGR valve and coupled between the second exhaust manifold and an intake passage, upstream of a compressor driven by the turbine;
• a bypass passage including a bypass valve and coupled between the second exhaust manifold and the exhaust passage, downstream of the turbine;
• and
• a controller including non-transitory instructions stored in memory for:
• diagnosing each of a position of the EGR valve, a position of the bypass valve, and a timing of the second set of cylinder exhaust valves based on an output of a pressure sensor disposed in the second exhaust manifold, and
• controlling a pressure in the second exhaust manifold to a demanded level via adjusting one or more of the position of the bypass valve and the timing of the second set of cylinder exhaust valves in response to diagnosing that the position of the EGR valve is different than commanded.