An auxiliary power unit for an aircraft includes a rotary intermittent internal combustion engine drivingly engaged to an engine shaft, a turbine section having an inlet in fluid communication with an outlet of the engine(s), the turbine section including at least one turbine compounded with the engine shaft, and a compressor having an inlet in fluid communication with an environment of the aircraft and an outlet in fluid communication with a bleed duct for providing bleed air to the aircraft, the compressor having a compressor rotor connected to a compressor shaft, the compressor shaft drivingly engaged to the engine shaft. The driving engagement between the compressor shaft and the engine shaft is configurable to provide at least two alternate speed ratios between the compressor shaft and the engine shaft.

An auxiliary power unit for an aircraft includes a rotary intermittent internal combustion engine drivingly engaged to an engine shaft, a turbine section having an inlet in fluid communication with an outlet of the engine(s), the turbine section including at least one turbine compounded with the engine shaft, and a compressor having an inlet in fluid communication with an environment of the aircraft and an outlet in fluid communication with a bleed duct for providing bleed air to the aircraft, the compressor having a compressor rotor connected to a compressor shaft, the compressor shaft drivingly engaged to the engine shaft. The driving engagement between the compressor shaft and the engine shaft is configurable to provide at least two alternate speed ratios between the compressor shaft and the engine shaft.

Damping members for turbocharger assemblies, methods for providing turbocharger assemblies, and turbocharger assemblies are described herein. The damping members include bodies having shapes to fit between a recess extending into a rotor disk of a turbocharger and laterally protruding shoulders of platforms in neighboring blades of the turbocharger. The bodies dampen vibrations of the blades during rotation of the blades. The damping members may include a variety of shapes, such as a sheet, a wedge, a tapered pin, a cylindrical pin, a bent sheet, or another shape.

Damping members for turbocharger assemblies, methods for providing turbocharger assemblies, and turbocharger assemblies are described herein. The damping members include bodies having shapes to fit between a recess extending into a rotor disk of a turbocharger and laterally protruding shoulders of platforms in neighboring blades of the turbocharger. The bodies dampen vibrations of the blades during rotation of the blades. The damping members may include a variety of shapes, such as a sheet, a wedge, a tapered pin, a cylindrical pin, a bent sheet, or another shape.

A supercharging device (20), having: a housing (21) which has a longitudinal axis (L); at least one housing inlet (1) which leads into the housing (21); at least one housing outlet (2) which leads out of the housing (21); at least one compressor wheel (5) which is arranged in a compressor chamber (15) and which is driven by a motor shaft (16) and which is arranged between the housing inlet (1) and the housing outlet (2) of the housing (21) as viewed in the flow direction, and at least one bypass duct (17) which is integrated in the housing (21) and which connects the housing inlet (1) to the housing outlet (2) so as to bypass the compressor chamber (15). The bypass duct (17) has a self-adjusting valve (22). The housing inlet (1) and the housing outlet (2) are formed as an axial inlet and an axial outlet respectively.

A supercharging device (20), having: a housing (21) which has a longitudinal axis (L); at least one housing inlet (1) which leads into the housing (21); at least one housing outlet (2) which leads out of the housing (21); at least one compressor wheel (5) which is arranged in a compressor chamber (15) and which is driven by a motor shaft (16) and which is arranged between the housing inlet (1) and the housing outlet (2) of the housing (21) as viewed in the flow direction, and at least one bypass duct (17) which is integrated in the housing (21) and which connects the housing inlet (1) to the housing outlet (2) so as to bypass the compressor chamber (15). The bypass duct (17) has a self-adjusting valve (22). The housing inlet (1) and the housing outlet (2) are formed as an axial inlet and an axial outlet respectively.

To improve the controllability of the feedback control of the boost pressure, an ECU comprises a valve control part that feedback controls a boost pressure of a turbocharger based on a deviation between a target boost pressure and an actual boost pressure, and a determination part that determines whether or not the exhaust state in an exhaust passage can achieve the target boost pressure, and the feedback control includes at least an integral term, and when the determination part determines the exhaust state cannot achieve the target boost pressure, the valve control part reduces the influence of the deviation on the calculation of integral term compared with that when the exhaust state can achieve the target boost pressure.

To improve the controllability of the feedback control of the boost pressure, an ECU comprises a valve control part that feedback controls a boost pressure of a turbocharger based on a deviation between a target boost pressure and an actual boost pressure, and a determination part that determines whether or not the exhaust state in an exhaust passage can achieve the target boost pressure, and the feedback control includes at least an integral term, and when the determination part determines the exhaust state cannot achieve the target boost pressure, the valve control part reduces the influence of the deviation on the calculation of integral term compared with that when the exhaust state can achieve the target boost pressure.

An object is to provide a structure and a method of joining a nozzle vane and a lever, and a variable geometry turbocharger, capable of reducing breakage of a welded part between a shaft portion of the nozzle vane and the lever during usage of the same by reducing generation of a hot crack in weld metal at the welded part. A joint structure includes: a nozzle vane 2 disposed in an exhaust passage for guiding exhaust gas to a turbine wheel 34 of a variable geometry turbocharger 500, and including a shaft portion 2a; and a lever 1 including a fitting surface 42a fitted with a peripheral surface 72 on one end side of the shaft portion, for transmitting torque to the shaft portion to adjust a vane angle of the nozzle vane. Weld metal 50 at a welded part 40 between the lever and the nozzle vane is formed so that a center position 64 of the weld metal is disposed inside a position 17 of the fitting surface with respect to a radial direction of the shaft portion.

An object is to provide a structure and a method of joining a nozzle vane and a lever, and a variable geometry turbocharger, capable of reducing breakage of a welded part between a shaft portion of the nozzle vane and the lever during usage of the same by reducing generation of a hot crack in weld metal at the welded part. A joint structure includes: a nozzle vane 2 disposed in an exhaust passage for guiding exhaust gas to a turbine wheel 34 of a variable geometry turbocharger 500, and including a shaft portion 2a; and a lever 1 including a fitting surface 42a fitted with a peripheral surface 72 on one end side of the shaft portion, for transmitting torque to the shaft portion to adjust a vane angle of the nozzle vane. Weld metal 50 at a welded part 40 between the lever and the nozzle vane is formed so that a center position 64 of the weld metal is disposed inside a position 17 of the fitting surface with respect to a radial direction of the shaft portion.