A dual turbocharger system for an engine is provided. In one example, the dual turbocharger system may include two variable geometry turbines (VGTs), with each turbine being of the same size and operating in parallel, and with each compressor of the turbocharger operating in series, the first compressor of the first turbocharger being larger than the second compressor of the second turbocharger.

A waste gate assembly for a turbocharger includes a valve member formed by a valve shaft and an arm attached to an end of the shaft, the arm defining a through bore, an inner surface of the through bore defining an arm groove therein. A poppet for the valve has a pin whose outer surface defines a pin groove. A generally polygonal retaining ring of elastically deformable wire is installed partially in the arm groove and partially in the pin groove to retain the poppet on the pin, thereby attaching the poppet to the arm of the valve member. An anti-rotation feature prevents relative rotation of the poppet about the pin axis. Vertices of the retaining ring are in the arm groove, while sides of the retaining ring are in the pin groove. Once the retaining ring is pre-installed in the arm groove of the arm, the arm can be assembled to the poppet by a push-to-connect process.

A waste gate assembly for a turbocharger includes a valve member formed by a valve shaft and an arm attached to an end of the shaft, the arm defining a through bore, an inner surface of the through bore defining an arm groove therein. A poppet for the valve has a pin whose outer surface defines a pin groove. A generally polygonal retaining ring of elastically deformable wire is installed partially in the arm groove and partially in the pin groove to retain the poppet on the pin, thereby attaching the poppet to the arm of the valve member. An anti-rotation feature prevents relative rotation of the poppet about the pin axis. Vertices of the retaining ring are in the arm groove, while sides of the retaining ring are in the pin groove. Once the retaining ring is pre-installed in the arm groove of the arm, the arm can be assembled to the poppet by a push-to-connect process.

An engine including an exhaust bypass valve and an intake bypass valve. The exhaust bypass valve is disposed in an exhaust bypass channel connecting an outlet of an exhaust manifold and an exhaust outlet of a turbocharger to each other. The intake bypass valve is disposed in an intake bypass channel connecting an inlet of an intake manifold and an inlet of the turbocharger. An intake pressure sensor detects a pressure of the intake manifold. If an instruction value indicating an upper limit or a lower limit of the valve opening degree of the intake bypass valve is continuously output for a predetermined time or more, an engine control device determines that an abnormality occurs in at least one of the exhaust bypass valve and the intake bypass valve.

An engine including an exhaust bypass valve and an intake bypass valve. The exhaust bypass valve is disposed in an exhaust bypass channel connecting an outlet of an exhaust manifold and an exhaust outlet of a turbocharger to each other. The intake bypass valve is disposed in an intake bypass channel connecting an inlet of an intake manifold and an inlet of the turbocharger. An intake pressure sensor detects a pressure of the intake manifold. If an instruction value indicating an upper limit or a lower limit of the valve opening degree of the intake bypass valve is continuously output for a predetermined time or more, an engine control device determines that an abnormality occurs in at least one of the exhaust bypass valve and the intake bypass valve.

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.

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.

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 engine including an exhaust bypass valve and an intake bypass valve. The exhaust bypass valve is disposed in an exhaust bypass channel connecting an outlet of an exhaust manifold and an exhaust outlet of a turbocharger to each other. The intake bypass valve is disposed in an intake bypass channel connecting an inlet of an intake manifold and an inlet of the turbocharger. An intake pressure sensor detects a pressure of the intake manifold. If an instruction value indicating an upper limit or a lower limit of the valve opening degree of the intake bypass valve is continuously output for a predetermined time or more, an engine control device determines that an abnormality occurs in at least one of the exhaust bypass valve and the intake bypass valve.