Methods and systems are provided for enhancing turbocharger performance for a boosted engine system configured to operate with a pattern of deactivated cylinders. In one example, a method may include, in response to a demand for boost, operating with a cylinder pattern based on boost demand and turbocharger configuration. The specific pattern may depend on the pattern constraints imposed by engine load and NVH metrics.

A turbine comprises a turbine wheel for rotation within a turbine housing, the turbine housing including at least one volute arranged to deliver a fluid to the turbine wheel via the turbine nozzle. A method for determining a width of a turbine nozzle for the turbine, comprises selecting from a relationship between a turbine stage efficiency and an effective nozzle area, at least one target effective nozzle area. As used here, the effective nozzle area is dependent on both the width of the turbine nozzle and a whirl angle induced by the at least one volute. The method further comprises determining, in dependence on the whirl angle, the width of the turbine nozzle as a width that will achieve the at least one target effective nozzle area.

A turbocharger arrangement includes a turbine housing with multiple individual cylinder exhaust delivery scrolls, each having an individual inlet to the turbine, formed therein. The turbine housing has one individual cylinder exhaust delivery scroll for each cylinder of an engine to which the turbocharger arrangement is attached. Individual runner exhaust manifolds each connect one exhaust port of one cylinder of the engine to one of the individual cylinder exhaust delivery scrolls. The individual runner exhaust manifolds may be pipes of approximately equal length and/or equal gas flow characteristics. Separating the exhaust pulses from each cylinder with individually runner exhaust manifolds and turbine scrolls allows for enthalpy in the exhaust flow to be harnessed to a greater extent, and allows the system to be tuned for optimum energy recovery from engine cylinder blowdown.

Systems, apparatus, and methods are disclosed that include a divided exhaust engine with at least one pair of primary EGR cylinders and a plurality of pairs of non-primary EGR cylinders. The pair of primary EGR cylinders can be connected to an intake with an EGR system that lacks an EGR cooler. In another embodiment, the cylinder pairs include exhaust flow paths that join in the cylinder head to form a common exhaust outlet for each cylinder pair in the cylinder head that is connected directly to the EGR system or to the exhaust system without an exhaust manifold.

A system and method of controlling a turbocharged engine system includes receiving a boost mode selection signal and controlling the turbocharged engine system in response to the boost mode selection signal.

Methods and systems are provided for a turbocharger. In one example, a method may include bypassing exhaust gases flowing to the turbocharger in response to a catalyst temperature being less than a threshold temperature. The bypassing includes opening a bypass valve and adjusting a position of one or more turbine nozzle vanes.

An exhaust gas-conducting section of an exhaust turbocharger comprises a duct with a through-flow opening which can be fully or at least partially blocked or released by a closure element of a control device. The closure element is designed as a poppet valve. The closure element can be moved by an actuator can be disposed in a wall of the exhaust gas-conducting section. The closure element has a closure body with an annular section surface on its bottom surface which faces the through-flow opening. The section surface corresponds to an element seat formed in the wall. Its top surface faces away from the bottom surface and is designed in a profiled manner in order to produce a top surface at least partially corresponding to another element seat and/or to achieve flow-optimized circulation.

An exhaust passage including a protrusion which is less likely to receive heat from a gas and hence has high heat-resistance reliability is provided. An exhaust passage includes an exhaust pipe, and a protrusion continuously formed over a range of a part of an inner surface of the exhaust pipe in a circumferential direction thereof, the protrusion being inclined toward a direction in which the exhaust pipe extends, and being configured in such a manner that a cross-sectional area of the exhaust pipe becomes smaller toward a downstream side thereof, in which the exhaust passage further includes a convex part on an inner surface of the protrusion.

A turbine includes: an inner diameter side exhaust flow path; an outer diameter side exhaust flow path having a flow path cross-sectional area smaller than a flow path cross-sectional area of the inner diameter side exhaust flow path; an inner diameter side bypass flow path connecting the inner diameter side exhaust flow path and a discharge flow path; and an outer diameter side bypass flow path connecting the outer diameter side exhaust flow path and the discharge flow path, the outer diameter side bypass flow path having a flow path cross-sectional area larger than a flow path cross-sectional area of the inner diameter side bypass flow path.

Methods and systems are provided for a turbocharger. In one example, a method may include bypassing exhaust gases flowing to the turbocharger in response to a catalyst temperature being less than a threshold temperature. The bypassing includes opening a bypass valve and adjusting a position of one or more turbine nozzle vanes.