An internal combustion engine (20) has two exhaust valves (24, 25) for each combustion chamber, to permit separation of blow-down and expulsion phases of an exhaust stroke. The separate exhaust streams are directed to different geometries of an exhaust turbocharger (30), so as to make best use thereof. Variable exhaust valve timing, and bypass passage for the exhaust streams are disclosed.

A method performed by a control unit (11) for controlling exhaust valves (1A-6A, 1B-6B) of cylinders (1-6) in an internal combustion engine (10) is provided. The method comprise controlling (410) a number of first exhaust valves (1A-3A) for a first set of cylinders (1-3) to transfer exhaust gas to a turbine (8)) during part of an exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) via a first exhaust manifold (12). Also, the method comprises controlling (420) a number of second exhaust valves (1B-3B) for the first set of cylinders (1-3) to transfer exhaust gas to an exhaust gas recirculation, EGR, conduit (9)) during part of the exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) via a second exhaust manifold (7). The method further comprises controlling (430) a number of first exhaust valves (4A-6A) for a second set of cylinders (4-6) to transfer exhaust gas to the turbine (8) during part of an exhaust phase (Δt.sub.2) of the second set of cylinders (4-6) via the first exhaust manifold (12). Furthermore, the method comprises controlling (440) a number of second exhaust valves (4B-6B) for the second set of cylinders (4-6) to transfer exhaust gas to the EGR conduit (9) during a part of the exhaust phase (Δt.sub.2) of the second set of cylinders (4-6) via the second exhaust manifold (7). Here, the exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) is separated in time from the exhaust phase (Δt.sub.2) of the second set of cylinders (4-6).

A control unit (11), a computer program, a carrier, an internal combustion engine and a vehicle is also provided.

Systems and methods for determining which of an intake valve and an exhaust valve is to be deactivated first when an engine is operated in a variable displacement mode. In one example, an exhaust valve of the cylinder is deactivated before an intake valve of the cylinder when the engine is operated in a static variable displacement operating mode.

Methods and systems are provided for a prechamber. In one example, a system includes a plurality of openings angularly arranged in a prechamber wall. The plurality of openings is oriented to receive and expel fluids in clockwise or counterclockwise directions.

A method performed by a control unit (11) for controlling exhaust valves (1A-6A, 1B-6B) of cylinders (1-6) in an internal combustion engine (10) is provided. The method comprise controlling (410) a number of first exhaust valves (1A-3A) for a first set of cylinders (1-3) to transfer exhaust gas to a turbine (8)) during part of an exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) via a first exhaust manifold (12). Also, the method comprises controlling (420) a number of second exhaust valves (1B-3B) for the first set of cylinders (1-3) to transfer exhaust gas to an exhaust gas recirculation, EGR, conduit (9)) during part of the exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) via a second exhaust manifold (7). The method further comprises controlling (430) a number of first exhaust valves (4A-6A) for a second set of cylinders (4-6) to transfer exhaust gas to the turbine (8) during part of an exhaust phase (Δt.sub.2) of the second set of cylinders (4-6) via the first exhaust manifold (12). Furthermore, the method comprises controlling (440) a number of second exhaust valves (4B-6B) for the second set of cylinders (4-6) to transfer exhaust gas to the EGR conduit (9) during a part of the exhaust phase (Δt.sub.2) of the second set of cylinders (4-6) via the second exhaust manifold (7). Here, the exhaust phase (Δt.sub.1) of the first set of cylinders (1-3) is separated in time from the exhaust phase (Δt.sub.2) of the second set of cylinders (4-6). A control unit (11), a computer program, a carrier, an internal combustion engine and a vehicle is also provided.

An internal combustion engine includes combustion chambers, each having a first intake port, and first and second exhaust ports. An intake manifold is connected to the first intake port of each combustion chamber, a main pressure booster upstream of the intake manifold. An exhaust discharge arrangement includes a main exhaust manifold connected to the first exhaust port of each combustion chamber, the exhaust discharge arrangement connected to the second exhaust port of a first subset combustion chambers, and an exhaust recirculation manifold connected to the second exhaust port of a second subset combustion chambers and connected to an upstream side of the main pressure booster. The engine operates in high load and low load modes, which vary how the engine evacuates the exhaust gas of the second subset combustion chambers to the exhaust recirculation manifold. A related method is also disclosed.

An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system to provide air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through respective one of a plurality of exhaust valves. A valve train is provided for cylinder deactivation of a first part of the plurality of cylinders and compression release braking on a second part of the plurality of cylinders.

Systems and methods for determining which of an intake valve and an exhaust valve is to be deactivated first when an engine is operated in a variable displacement mode. In one example, an exhaust valve of the cylinder is deactivated before an intake valve of the cylinder when the engine is operated in a static variable displacement operating mode.

A combustion engine is provided having combustion chambers with reciprocating pistons, intake ports and exhaust ports. Transfer ports may be provided between adjacent combustion chambers to provide a transfer channel that closes during a high load mode of operation of the engine and opens during a partial load mode of operation. Also provided are embodiments in which exhaust ports of adjacent combustion chambers are joined into a common exhaust channel that communicates with an exhaust header of the engine through valve means that open during the high load mode of operation of said engine and close during a partial load mode of operation.

An engine includes at least one cylinder, a first intake valve and a second intake valve associated with the cylinder, to control a flow of intake air from a first intake duct and a second intake duct, respectively. The two intake ducts communicate with a common intake manifold, so as to receive air at the same pressure. During the intake stage, in each cylinder operating cycle, initially an opening and closing movement of only the first intake valve is activated, while the second intake valve remains closed and, subsequently, an opening and closing movement of only said second intake valve is activated, while the first intake valve remains closed. In this way, the two air flows at the same pressure entering the cylinder give rise to a high turbulent kinetic energy, to the advantage of combustion efficiency and reduction of harmful exhaust emissions.