Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, the split exhaust engine system may include a first set of exhaust valves fluidly coupled to the exhaust passage, upstream of a turbocharger turbine, a first emission control device (ECD), and a second ECD disposed within the exhaust passage, the second ECD positioned downstream of the first ECD. The system may further include a second set of exhaust valves fluidly coupled to the intake passage and the exhaust passage, between the first ECD and the second ECD.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, all intake valves of an engine cylinder may be deactivated, in response to engine load below a threshold, while operating a first exhaust valve coupled to the first exhaust manifold and a second exhaust valve coupled to the second exhaust manifold at different timings. As a result, intake air may be routed from the intake passage, through an exhaust gas recirculation passage coupled between the intake passage and the first exhaust manifold, and into the engine cylinder via the first exhaust valve.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, exhaust from a first set of exhaust valves coupled to the first exhaust manifold may be selectively routed to the intake passage via each of a first EGR passage coupled to the intake passage upstream of a compressor driven by a turbine and a second EGR passage coupled downstream of an outlet of the compressor. A decision of whether to route exhaust gas to the intake passage via the first EGR passage, second EGR passage, or both passages may be based on engine operating conditions.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, during a cold start, a method may include adjusting a position of a first valve disposed in an exhaust gas recirculation (EGR) passage based on an engine operating condition, the EGR passage coupled between the first exhaust manifold coupled to a first set of exhaust valves and the intake passage, upstream of a compressor. As one example, the engine operating condition may include an engine temperature or a temperature of a catalyst disposed in the exhaust passage.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, a method may include decreasing gas flow from the first exhaust manifold to the intake passage, upstream of a compressor, where a first set of exhaust valves are exclusively coupled to the first exhaust manifold, in response to a condition of the compressor. Further, the method may include increasing gas flow from the first exhaust manifold to an exhaust passage coupled to a second exhaust manifold coupled to a second set of exhaust valves, in response to the decreasing gas flow.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, a flow of exhaust (e.g., exhaust gas recirculation) from engine cylinders to the intake passage, upstream of a compressor, via an exhaust gas recirculation (EGR) passage and the first exhaust manifold may be adjusted by adjusting a timing of a first set of cylinder exhaust valves coupled to the first exhaust manifold. Additionally, the first set of cylinder exhaust valves open at a different time than a second set of cylinder exhaust valves coupled to the exhaust passage.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, a first set of exhaust valves coupled to the first exhaust manifold may be operated at a different timing than a second set of exhaust valves coupled to the second exhaust manifold. Further, a position of a first valve positioned in a first passage coupled between the intake passage and the first exhaust manifold and/or a timing of the first set of exhaust valves may be diagnosed based on an output of a pressure sensor positioned in the first exhaust manifold.

Abstract: Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, in response to flowing the exhaust gas recirculation and blowthrough air from the first exhaust manifold to the intake passage via a first set of exhaust valves, a first set of swirl valves coupled upstream of a first set of intake valves may be adjusted to at least partially block intake air flow to the first set of intake valves. Each engine cylinder may include two intake valves including one of the first set of intake valves and two exhaust valves.

Abstract: Methods and systems are provided for operating an engine with variable displacement engine (VDE) operation coupled to a twin scroll turbocharger. One method comprises directing exhaust from a first outer cylinder and a first inner cylinder of four cylinders to a first scroll of the twin scroll turbocharger, directing exhaust from a second outer cylinder and a second inner cylinder of the four cylinders to a second scroll of the twin scroll turbocharger, and during a first condition, firing all four cylinders with uneven firing.

Abstract: Methods and systems are provided for controlling vibrations during transitions between engine operating modes in a four-cylinder engine. One method includes timing a transition in engine operation between two-cylinder, three-cylinder, and four-cylinder modes with a sequence of firing events such that successive firing events are separated by at least 120 crank angle degree intervals. Vibrations resulting from transitions may be countered by adjusting active mounts, the active mounts being adjusted in synchronization with a valvetrain switching solenoid.

Abstract: Methods and systems are provided for adjusting the opening of a scroll valve of a binary flow turbine. Scroll valve adjustments are used at different engine operating conditions to improve engine performance and boost response. Scroll valve adjustments are coordinated with wastegate and EGR valve adjustments for improved engine control.

Abstract: Methods and systems are provided for improving combustion stability, in particular during transient operations such as tip-out to lower load conditions, when EGR is being purged. Until a desired LP-EGR rate is achieved, fuel may be delivered as a split injection with at least an intake stroke injection and a compression stroke injection. Subsequently, single fuel injection may be resumed.

Abstract: Methods and systems are provided for improving engine knock tolerance, in particular when rapidly ramping in LP-EGR from low levels of EGR. Until a desired LP-EGR rate is achieved, fuel may be delivered as a split injection with at least an intake stroke injection and a compression stroke injection to compensate for the transport delay in EGR filling the intake system. Subsequently, single fuel injection may be resumed.

Abstract: Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

Abstract: Methods and systems for adjusting a branch communication and wastegate valve in a dual scroll turbocharger system are provided. In one example, a method may include adjusting the branch communication and wastegate valve in a passage connecting a first scroll, a second scroll, and a wastegate passage may control an amount of exhaust flow to a turbine during certain engine operating conditions.

Abstract: Methods and systems are provided for operating an engine with variable displacement engine (VDE) operation coupled to a twin scroll turbocharger. One method comprises directing exhaust from a first outer cylinder and a first inner cylinder of four cylinders to a first scroll of the twin scroll turbocharger, directing exhaust from a second outer cylinder and a second inner cylinder of the four cylinders to a second scroll of the twin scroll turbocharger, and during a first condition, firing all four cylinders with uneven firing.

Abstract: Methods and systems are provided for controlling transitions between engine operating modes in a four-cylinder engine. One method includes transitioning engine operation between two-cylinder, three-cylinder, and four-cylinder modes wherein the transitioning includes a sequence of firing events such that successive firing events are separated by at least 120 crank angle degree intervals.

Abstract: Methods and systems are provided for improving engine knock tolerance, in particular when rapidly ramping in LP-EGR from low levels of EGR. Until a desired LP-EGR rate is achieved, fuel may be delivered as a split injection with at least an intake stroke injection and a compression stroke injection to compensate for the transport delay in EGR filling the intake system. Subsequently, single fuel injection may be resumed.

Abstract: Methods and systems are provided for a boosted engine having a split exhaust system. In one example, a method comprises directing exhaust from a first cylinder group to one or more of a pre-compressor location, a post-compressor location, and an exhaust turbine, and directing exhaust from a second cylinder group to one or more of the pre-compressor location, and the exhaust turbine. Engine efficiency and knock control may be enhanced by directing exhaust gases to different locations based on engine operating conditions.