A turbocharger includes a housing and a rotor with a shaft that is housed within the housing. The turbocharger also includes a bearing structure that supports rotation of the shaft within the housing and a locating fastener that retains the bearing structure in a position relative to the housing. Furthermore, the turbocharger includes a heating system coupled to the locating fastener and that is configured for selectively heating the locating fastener.

A dual volute turbocharger for use with an internal combustion engine includes a valve for controlling exhaust gas flow to a turbine housing interior of the dual volute turbocharger. The dual volute turbocharger also includes a first volute and a second volute each adapted for fluid communication with the internal combustion engine. The dual volute turbocharger further includes a wall separating the first and second volutes and a valve seat. The valve seat and the wall collectively define a valve cavity. The valve is movable between a closed position and an open position. The valve and the wall of the turbine housing collectively define a first cross-sectional flow area. The valve and the valve seat collectively define a second cross-sectional flow area. A method of controlling the valve of the dual volute turbocharger is also disclosed.

A dual volute turbocharger for use with an internal combustion engine includes a valve for controlling exhaust gas flow to a turbine housing interior of the dual volute turbocharger. The dual volute turbocharger also includes a first volute and a second volute each adapted for fluid communication with the internal combustion engine. The dual volute turbocharger further includes a wall separating the first and second volutes and a valve seat. The valve seat and the wall collectively define a valve cavity. The valve is movable between a closed position and an open position. The valve and the wall of the turbine housing collectively define a first cross-sectional flow area. The valve and the valve seat collectively define a second cross-sectional flow area. A method of controlling the valve of the dual volute turbocharger is also disclosed.

A turbocharger includes a compressor housing, turbine housing, and center housing between the compressor and turbine housings. A turbine wheel is disposed in the turbine housing on a turbine shaft. A compressor wheel having a shank is disposed in the compressor housing on the turbine shaft. The shank has outer and reduced portions. The reduced portion has a smaller diameter than the outer portion. A backplate is mounted to the compressor housing adjacent the compressor wheel and defines a stepped cylindrical bore with a maximum diameter portion and a minimum diameter portion having a smaller diameter than the maximum portion. The outer portion is disposed in the maximum portion. The reduced portion is disposed in the minimum portion. The outer diameter of the shank is greater than or equal to the minimum diameter of the backplate, and the stepped cylindrical bore and the shank define a variable width gap.

A turbocharger includes a compressor housing, turbine housing, and center housing between the compressor and turbine housings. A turbine wheel is disposed in the turbine housing on a turbine shaft. A compressor wheel having a shank is disposed in the compressor housing on the turbine shaft. The shank has outer and reduced portions. The reduced portion has a smaller diameter than the outer portion. A backplate is mounted to the compressor housing adjacent the compressor wheel and defines a stepped cylindrical bore with a maximum diameter portion and a minimum diameter portion having a smaller diameter than the maximum portion. The outer portion is disposed in the maximum portion. The reduced portion is disposed in the minimum portion. The outer diameter of the shank is greater than or equal to the minimum diameter of the backplate, and the stepped cylindrical bore and the shank define a variable width gap.

An internal combustion engine having an exhaust log structure onto which a plurality of turbochargers is connected, each turbocharger having a turbine connected to the exhaust log structure and having an inlet fluidly connectable to a respective one of the plurality of outlet ports, an exhaust valve disposed at a turbine outlet such that the flow of exhaust gas out of the turbine is fluidly blocked, and an actuator associated with the exhaust valve and operating to move the exhaust valve from a closed position to an open position and vice versa. An electronic controller provides a command to the actuator to move the exhaust valve between the open and closed positions and is programmed to selectively open two one or more exhaust valves based on an operating condition of the engine.

An intercooler lid assembly for an intercooler supercharger system, comprising: an intercooler lid mountable to a supercharger housing; a plurality of intercooler cores coupled together, and mounted to and within the intercooler lid to cool supercharger air prior to receipt by an engine, wherein the intercooler lid assembly is pre-assembled and mounted onto the supercharger housing to install the intercooler lid assembly.

A mechanical supercharging system includes a stepped transmission that connects a crankshaft of an internal combustion engine with driving wheels, a centrifugal supercharger including a rotary drive shaft connected to the crankshaft, a variable speed ratio device that changes a speed ratio of the rotary drive shaft to the crankshaft, the variable speed ratio device being provided between the crankshaft and the rotary drive shaft; and a control device configured to control the speed ratio. The control device increases the speed ratio during the upshift operation more than the speed ratio before start of the upshift operation.

A mechanical supercharging system includes a stepped transmission that connects a crankshaft of an internal combustion engine with driving wheels, a centrifugal supercharger including a rotary drive shaft connected to the crankshaft, a variable speed ratio device that changes a speed ratio of the rotary drive shaft to the crankshaft, the variable speed ratio device being provided between the crankshaft and the rotary drive shaft; and a control device configured to control the speed ratio. The control device increases the speed ratio during the upshift operation more than the speed ratio before start of the upshift operation.

Methods and systems are provided for improving transient performance in a boosted engine having staged air compression systems. An electric supercharger compressor is staged downstream of a turbocharger compressor in a bypass, airflow diverted from a main intake passage to the bypass via closure of a bypass valve. During selected conditions when the supercharger compressor is not being spun, the bypass valve may be closed to direct air to the engine after flowing through the supercharger in a stand-by mode, thereby enabling a transient increase in torque demand to be rapidly met.