An electric assist turbocharger unit for use in an internal combustion engine, comprising a shaft configured for torque-transmittingly connecting a compressor to a turbine of the turbocharger unit and an electric motor configured for rotatably actuating the shaft in a first rotational direction and in an opposed second rotational direction. The engine includes an aftertreatment system, and the rotation of the shaft is designed to retard the flow of intake air through an intake passage and of exhaust gases through the aftertreatment system, thereby controlling the temperature in the aftertreatment system.

A supercharging system includes: a first supercharger including a first compressor for compressing air to be supplied to an engine; a second supercharger including a second compressor for further compressing air compressed by the first compressor; and a controller for controlling the first supercharger and the second supercharger. At least one of the first supercharger or the second supercharger further includes an electric motor for driving the first compressor or the second compressor. At least one of the first supercharger or the second supercharger further includes a turbine configured to be rotary driven by exhaust gas from the engine, and a nozzle vane configured to adjust a flow-path area of the exhaust gas flowing into the turbine. The controller includes: an electric motor control part configured to, if an amount of charge of a battery for supplying electric power to the electric motor is less than a first threshold, set an upper limit value of an output command value for the electric motor to be lower than when the amount of charge of the battery is not less than the first threshold, or switch operation of the electric motor to regenerative operation; and a vane control part configured to, if the amount of charge of the battery is less than the first threshold, control an opening degree of the nozzle vane so that the flow-path area decreases with a control of the electric motor by the electric motor control part.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

An internal combustion gas engine (2) is disclosed. It includes a cylinder arrangement (4) and a first compressor (6) for compressing a gaseous fuel and air mixture. The at least one cylinder arrangement (4) forms a combustion chamber (8) and includes an intake arrangement (10) for intake of charge gas, a sparkplug (12), and a pre-chamber (14). The engine (2) comprises a second compressor (16) for compressing a gaseous medium, and a pressure reducer (18). An outlet (20) of the first compressor (6) is arranged in parallel with an outlet (22) of the second compressor (16). The outlet (20) of the first compressor (6) is connected to the pre-chamber (14). The outlet (20) of the first compressor (6) and the outlet (22) of the second compressor (16) are connected to the pressure reducer (18). An outlet (24) of the pressure reducer (18) is connected to the intake arrangement (10).

A supercharging system includes a first supercharger including a first compressor; a second supercharger including a second compressor provided downstream of the first compressor, and a controller controlling the first and second superchargers. At least one of the first and second superchargers includes an electric motor for driving the first or second compressor. At least one of the first and second superchargers includes a turbine, and a nozzle vane that adjusts a flow-path area of the exhaust gas flowing into the turbine. When a charge amount of a battery is low, the controller sets an upper limit of an output command value for the motor to be lower than when the charge amount is not low, or starts regenerative operation of the motor. A vane control part controls an opening degree of the nozzle vane so that the flow-path area decreases with a control of the electric motor.

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.

An internal combustion gas engine (2) is disclosed. It includes a cylinder arrangement (4) and a first compressor (6) for compressing a gaseous fuel and air mixture. The at least one cylinder arrangement (4) forms a combustion chamber (8) and includes an intake arrangement (10) for intake of charge gas, a sparkplug (12), and a pre-chamber (14). The engine (2) comprises a second compressor (16) for compressing a gaseous medium, and a pressure reducer (18). An outlet (20) of the first compressor (6) is arranged in parallel with an outlet (22) of the second compressor (16). The outlet (20) of the first compressor (6) is connected to the pre-chamber (14). The outlet (20) of the first compressor (6) and the outlet (22) of the second compressor (16) are connected to the pressure reducer (18). An outlet (24) of the pressure reducer (18) is connected to the intake arrangement (10).

A supercharging device for an internal combustion engine of a motor vehicle includes: an exhaust-gas turbocharger having a turbine wheel that can be driven by exhaust gas from the internal combustion engine and a first compressor wheel that can be driven by the turbine wheel, by which first compressor wheel air being supplied to the internal combustion engine is compressed; an electric compressor having an electric machine and a second compressor wheel that can be driven by the electric machine, by which second compressor wheel air being supplied to the internal combustion engine is compressed; and an overrun air recirculation device associated with the first compressor wheel, by which, when there is a reduction in load on the internal combustion engine, a portion of the air compressed by the first compressor wheel can be branched off at a first point arranged downstream of the first compressor wheel and can be fed back from the first point to a second point arranged upstream of the first compressor wheel, wherein the supercharging device supplies the second compressor wheel with the branched-off air such that the second compressor wheel and, via the second compressor wheel, the electric machine, can be driven by the branched-off air.

A butterfly bypass valve includes a housing defining a bypass flow passage with a pivotable throttle plate therein. An outer edge of the throttle plate in a closed position is in sealing engagement with a sealing portion of the housing such that the throttle plate restricts fluid flow through the bypass flow passage. The throttle plate is pivotable to an open position to allow fluid flow through the bypass flow passage. A port in the housing allows a portion of fluid passing through the bypass flow passage to be removed when the throttle plate is pivoted to the open position. A predetermined amount of pivoting of the throttle plate toward the open position can occur so as to allow flow through the port, while maintaining the edge of the throttle plate in substantially sealing engagement with the sealing portion so as to substantially prevent flow through the bypass passage.