Methods and systems are provided for providing exhaust gas recirculation to a naturally aspirated internal combustion engine. In one example, exhaust gas is recirculated to an engine intake via a dedicated scavenging manifold and a scavenging exhaust valve. The exhaust gas and fresh air that has not participated in combustion may be recirculated to engine cylinders even at high engine loads since the exhaust gas and fresh air is returned to the engine air intake at a pressure greater than atmospheric pressure.

A method for operating an internal combustion engine having an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine is acted on by an exhaust gas flow discharged from the engine. In a main operating mode, the engine operates the first number of cylinders in two-stroke operation and the second number of cylinders in four-stroke operation. A scavenging gradient of the engine is greater for the cylinders operated in the two-stroke operation than for the cylinders operated in the four-stroke operation.

Engine low pressure cooled exhaust gas recirculation (LPCEGR) control techniques comprise receiving a measured position of an accelerator pedal and, based on this measurement, detecting a transient tip-out event or a transient tip-in event. In response to detecting the transient tip-out event, an EGR depletion rate is temporarily increased by at least one of (i) downstream throttle valve control to maintain at least a minimum engine airflow or to regulate a rate of decrease of the airflow into the engine, (ii) cylinder bank fuel shutoff, and (iii) pre-scheduled EGR valve control based on the measured accelerator pedal position. In response to detecting the transient tip-in event, an EGR delivery rate is temporarily increased by at least one of (i) the pre-scheduled EGR valve control and (ii) controlling intake/exhaust valves of cylinders of the engine to enable a scavenging mode.

The internal combustion engine comprising: a catalyst arranged in an exhaust passage and able to store oxygen, a variable valve timing mechanism able to change a valve overlap amount between an intake valve and an exhaust valve, and a fuel supplying means for feeding fuel to the exhaust passage. The fuel supplying means feeds fuel to the exhaust passage only in an initial cycle after scavenging where valve overlap causes air to be expelled from an intake passage through a cylinder to the exhaust passage if such scavenging occurs.

Methods and systems are provided for reducing engine compression torque when an engine having a split exhaust system is spun unfueled. In one example, a method may include maintaining closed a blowdown exhaust valve of a cylinder, the blowdown exhaust valve coupled to a first exhaust manifold that directs gases from the cylinder to a catalyst, and opening a scavenge exhaust valve of the cylinder, the scavenge exhaust valve coupled to a second exhaust manifold that directs gases from the cylinder to an exhaust gas recirculation system. In this way, compression of gases within they cylinder is reduced while gas flow to the catalyst is prevented.

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.

A method for operating an internal combustion engine, device, and an internal combustion engine including a motor which has a crankshaft. A charge air flow is supplied to the motor that is compressed by means of a compressor via a second rotational movement, and a power turbine for producing a first rotational movement is acted on by an exhaust gas flow discharged from the motor. The following steps are provided: in a first operating mode, operating the internal combustion engine in four-stroke operation, and in a second operating mode, operating the internal combustion engine in two-stroke operation. The crankshaft can be driven by the power turbine via the first rotational movement, and the compressor can be driven by the crankshaft via the second rotational movement, wherein the second rotational movement for the compressor can be set differently from the first rotational movement of the power turbine.

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.

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 an electric motor driving an electric compressor positioned upstream of a turbocharger compressor disposed in the intake passage, a position of a valve in an exhaust gas recirculation (EGR) passage coupled between the intake passage and the first exhaust manifold may be adjusted based on a pressure in the first exhaust manifold.

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, one or more valves of a set of first exhaust valves coupled to the second exhaust manifold may be deactivated in response to select engine operating conditions, while maintaining active all valves of a set of second exhaust valves coupled to the first exhaust manifold. The select engine operating conditions may include one or more of a deceleration fuel shut-off condition, a part throttle condition, and a cold start condition.