Abstract: Methods and systems are provided for controlling camshaft phasers of a variable displacement engine. In one example, the engine includes first and second cylinder banks, with the engine being configured to operate in a rolling variable displacement mode. The camshaft phasers are torque actuated camshaft phasers, and a controller of the engine may adjust operation of camshaft phasers at the first cylinder bank differently than camshaft phasers at the second cylinder bank.

Abstract: Methods and systems are provided for controlling camshaft phasers of a variable displacement engine. In one example, the engine includes first and second cylinder banks, with the engine being configured to operate in a rolling variable displacement mode. The camshaft phasers are torque actuated camshaft phasers, and a controller of the engine may adjust operation of camshaft phasers at the first cylinder bank differently than camshaft phasers at the second cylinder bank.

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, 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 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 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 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 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 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 engine operation. One method comprises during a first condition, operating the engine with a single cylinder deactivated and remaining cylinders activated with a first intake duration, and during a second condition, operating the engine with the single cylinder deactivated and the remaining cylinders activated with a second intake duration. The method further comprises during a third condition, operating the engine with all cylinders activated.

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: Systems and methods for increasing an amount of fuel injected into a dedicated exhaust gas recirculation (EGR) cylinder in an engine are disclosed. In one example approach, a method comprises, prior to combustion, injecting a first amount of fuel to a dedicated EGR cylinder, and after combustion and during an expansion and/or exhaust stroke, directly injecting a second amount of fuel to the dedicated EGR cylinder.

Abstract: Systems and methods for actuating lobe switching in a camshaft system in an engine are disclosed. In one example approach, a method comprises deploying a first pin into a groove of a camshaft outer sleeve while a second pin remains in place due to an absence of a groove in which to deploy, and maintaining the second pin in place with a ball locking mechanism even after the second pin is exposed to a vacated groove in the camshaft outer sleeve.

Abstract: Methods and systems are provided for varying a location and rate of EGR delivered to an engine from a dedicated EGR cylinder. The dedicated EGR cylinder is configured with a plurality of exhaust valves controlled via a cam profile switching mechanism that allows the time and duration of opening of each exhaust valve to be varied. By selectively opening one exhaust valve at a time, exhaust from the dedicated EGR cylinder can be delivered to a pre-compressor location, a post-compressor location, or to the exhaust manifold, while bypassing all engine cylinders.

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: Various systems and methods are described for controlling engine operation. One method comprises, during a first variable displacement engine (VDE) mode in an engine having four cylinders, deactivating a first cylinder of the four cylinders and firing a second, third, and fourth cylinder of the four cylinders, each firing event separated by 240 degrees of crank angle (CA). The engine may be operated in a non-VDE mode by activating the first of the four cylinders and firing the first cylinder between the third and fourth cylinders.

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.