An internal combustion engine 31 for a motorcycle includes a supercharger 63 arranged above a crankcase 81 positioned below a front cylinder head 92 of a front bank 31A and a rear cylinder head 97 of a rear bank 31B. In the internal combustion engine 31 for the motorcycle, the crankcase 81 is covered with a case cover 116 from the outside in a vehicle width direction, and the supercharger 63 is supported by a supercharger supporting portion 116a provided above the case cover 116.

An internal combustion engine 31 for a motorcycle includes a supercharger 63 arranged above a crankcase 81 positioned below a front cylinder head 92 of a front bank 31A and a rear cylinder head 97 of a rear bank 31B. In the internal combustion engine 31 for the motorcycle, the crankcase 81 is covered with a case cover 116 from the outside in a vehicle width direction, and the supercharger 63 is supported by a supercharger supporting portion 116a provided above the case cover 116.

A control system for an internal combustion engine includes an electric supercharger that includes a compressor wheel that is configured to be rotated by an electric motor. The control system includes a bypass passage, a bypass valve, and an exhaust gas recirculation passage. The control device is configured to control the electric supercharger and the bypass valve based on an operation condition of the internal combustion engine. The control device is configured to cause a stepping operation of the electric supercharger in which acceleration and stopping of the compressor wheel are repeated within a predetermined cleaning time after operation of the internal combustion engine is stopped.

A turbine (3) includes: a turbine impeller chamber (43) having a tubular outflow portion (432), from which an exhaust gas flows out in an outflow direction (F) substantially parallel to an axis (C) of a turbine impeller (5); a bypass flow passage (491) bypassing the inside of the turbine impeller chamber; an outer duct (47) having an inner peripheral surface (475) that expands in diameter in the outflow direction from the outflow portion; and an inner duct (48) that extends in the outflow direction from the outflow portion. A diffuser flow passage (483) that expands in diameter in the outflow direction is disposed in the inner duct at least in a portion between the outflow portion and a distal end portion (481a). An outlet (492) of the bypass flow passage and a waste gate valve (493) that opens and closes the outlet are disposed on the inner peripheral surface.

A turbine (3) includes: a turbine impeller chamber (43) having a tubular outflow portion (432), from which an exhaust gas flows out in an outflow direction (F) substantially parallel to an axis (C) of a turbine impeller (5); a bypass flow passage (491) bypassing the inside of the turbine impeller chamber; an outer duct (47) having an inner peripheral surface (475) that expands in diameter in the outflow direction from the outflow portion; and an inner duct (48) that extends in the outflow direction from the outflow portion. A diffuser flow passage (483) that expands in diameter in the outflow direction is disposed in the inner duct at least in a portion between the outflow portion and a distal end portion (481a). An outlet (492) of the bypass flow passage and a waste gate valve (493) that opens and closes the outlet are disposed on the inner peripheral surface.

When the forced induction mode is a single forced induction mode, and when it is determined that there is a request for switching to a twin forced induction mode, the control device executes a process including the step of executing an approach-run operation, the step of executing a control for equalizing the VN opening degree, and the step of switching to the twin forced induction mode when it is determined that a second boost pressure has reached a first boost pressure.

When the forced induction mode is a single forced induction mode, and when it is determined that there is a request for switching to a twin forced induction mode, the control device executes a process including the step of executing an approach-run operation, the step of executing a control for equalizing the VN opening degree, and the step of switching to the twin forced induction mode when it is determined that a second boost pressure has reached a first boost pressure.

A method for operating an electric machine of a compressor and/or of a turbine, which includes a rotor situated on a shaft mounted rotatably in a housing and a stator fixed to the housing, the stator including an, in particular, multiphase drive winding, and an activation of the drive winding being suspended at least intermittently in an idling mode. It is provided that the shaft and/or the rotor is/are monitored for a rotary movement, and that, when a standstill or an impending standstill of the shaft and/or of the rotor is detected, the drive winding is activated in such a way that the rotor, at least briefly, is caused to carry out a movement and/or is centered with respect to the stator by magnetic force.

A method for operating an electric machine of a compressor and/or of a turbine, which includes a rotor situated on a shaft mounted rotatably in a housing and a stator fixed to the housing, the stator including an, in particular, multiphase drive winding, and an activation of the drive winding being suspended at least intermittently in an idling mode. It is provided that the shaft and/or the rotor is/are monitored for a rotary movement, and that, when a standstill or an impending standstill of the shaft and/or of the rotor is detected, the drive winding is activated in such a way that the rotor, at least briefly, is caused to carry out a movement and/or is centered with respect to the stator by magnetic force.

A centrifugal blower is described herein. The centrifugal blower may be a belt-driven geared centrifugal blower. The centrifugal blower may comprise an impeller, an inlet, and an outlet. The impeller pulls air in through the inlet, compresses and speeds up the air, and directs the air out the outlet. A motor may power a pulley system coupled to the belt that, in turn, drives a gear set. The gear set then drives the impeller. A mounting frame for the centrifugal blower may comprise a plurality of mounting holes for increasing the airflow to the gear set for cooling there. A belt tensioner may be coupled to the pulley system for setting a preload in the pulley system. An adjustment system for adjusting the tension provided by the belt tensioner is disclosed.