Abstract: A method is provided for preventing oil escape into an exhaust gas during operation of a turbocharged engine. The method includes providing pressurized fluid to an area sealing off a bearing housing of an axial turbine unit from an adjacent exhaust conduit downstream of the axial turbine unit, and detecting a malfunction in the provision of pressurized fluid. Further to this, the method includes the step of, in response to such malfunction detection, controlling an exhaust pressure increasing device arranged downstream of the axial turbine unit for increasing the pressure inside the exhaust conduit upstream of the exhaust pressure increasing device.

Abstract: A power turbine unit includes a turbine housing, an exhaust duct, a turbine wheel with blades positioned in the exhaust duct, a shaft rigidly connected to the turbine wheel and rotatably supported in the housing, and an oil sealing system. The oil sealing system includes a sealing arrangement positioned in the vicinity of the turbine wheel for preventing oil from escaping from the turbine housing along the shaft to the exhaust duct. The oil sealing system further includes a buffer gas duct that is arranged to supply exhaust gas from the exhaust duct to the sealing arrangement for pressurizing the sealing arrangement.

Abstract: A method is provided for preventing oil escape into an exhaust gas during operation of a turbocharged engine. The method includes providing pressurized fluid to an area sealing off a bearing housing of an axial turbine unit from an adjacent exhaust conduit downstream of the axial turbine unit, and detecting a malfunction in the provision of pressurized fluid. Further to this, the method includes the step of, in response to such malfunction detection, controlling an exhaust pressure increasing device arranged downstream of the axial turbine unit for increasing the pressure inside the exhaust conduit upstream of the exhaust pressure increasing device.

Abstract: A power turbine unit includes a turbine housing, an exhaust duct, a turbine wheel with blades positioned in the exhaust duct, a shaft rigidly connected to the turbine wheel and rotatably supported in the housing, and an oil sealing system. The oil sealing system includes a sealing arrangement positioned in the vicinity of the turbine wheel for preventing oil from escaping from the turbine housing along the shaft to the exhaust duct. The oil sealing system further includes a buffer gas duct that is arranged to supply exhaust gas from the exhaust duct to the sealing arrangement for pressurizing the sealing arrangement.