An engine including an exhaust bypass valve and an intake bypass valve. The exhaust bypass valve is disposed in an exhaust bypass channel connecting an outlet of an exhaust manifold and an exhaust outlet of a turbocharger to each other. The intake bypass valve is disposed in an intake bypass channel connecting an inlet of an intake manifold and an inlet of the turbocharger. An intake pressure sensor detects a pressure of the intake manifold. If an instruction value indicating an upper limit or a lower limit of the valve opening degree of the intake bypass valve is continuously output for a predetermined time or more, an engine control device determines that an abnormality occurs in at least one of the exhaust bypass valve and the intake bypass valve.

A method includes: determining that at least one cylinder of a first cylinder bank of an engine is active; determining that at least one cylinder of a second cylinder bank of the engine is inactive; receiving an inlet temperature of a selective catalytic reduction system; comparing the inlet temperature to a temperature setpoint; and adjusting at least one of a first exhaust manifold pressure setpoint for the first cylinder bank or a second exhaust manifold pressure setpoint for the second cylinder bank based on the comparison.

A method includes: determining that at least one cylinder of a first cylinder bank of an engine is active; determining that at least one cylinder of a second cylinder bank of the engine is inactive; receiving an inlet temperature of a selective catalytic reduction system; comparing the inlet temperature to a temperature setpoint; and adjusting at least one of a first exhaust manifold pressure setpoint for the first cylinder bank or a second exhaust manifold pressure setpoint for the second cylinder bank based on the comparison.

A method for operating a supercharged internal combustion engine. Before a cold start of the engine, an electric drive device of an electrically assisted exhaust-gas turbocharger of the engine is activated such that fresh air is compressed by a compressor of the turbocharger and, in the process, is heated and is conveyed via an open overrun air recirculation valve arranged downstream of the compressor, through a short circuit back to a suction side of the compressor of the turbocharger. A proportion of the air that is heated by way of the short-circuit operation of the compressor is, downstream of the compressor and upstream of a closed throttle flap of the engine, conducted via a secondary air system into an exhaust manifold and from there via a wastegate of the turbocharger into the catalytic converters of an exhaust-gas aftertreatment device of the engine.

A turbocharger includes a three-way rotary turbine bypass valve (TBV) operable to selectively supply exhaust gases to a turbine feed passage leading to a turbine wheel, and/or to a bypass passage that bypasses the turbine wheel. The TBV is structured and arranged to close the bypass outlet of the valve when the turbine outlet is fully open, to partially open the bypass passage while the turbine outlet remains fully open, to fully open the bypass passage when the turbine outlet is partially closed, and to fully open the bypass passage when the turbine passage is fully closed. The TBV turns the exhaust gas flows through acute angles between inlet and outlets, mitigating pressure losses through the valve. Leakage to bypass is minimized by a labyrinth seal formed when the valve member closes the bypass outlet.

An actuator assembly for a variable turbine geometry (VTG) turbocharger is disclosed. The actuator assembly may include an actuator and an actuator linkage having a first end coupled to the actuator and a second end defining a linkage joint. The actuator assembly may further include a VTG lever having a ball stud bore extending through the VTG lever. Additionally, the actuator assembly may include a ball stud including a first end partially disposed within the linkage joint and a second threaded end extending axially through the ball stud bore. Furthermore, a nut may be aligned with the ball stud bore and movably attached to the VTG lever prior to extending the ball stud through the ball stud bore, wherein the ball stud engages with the nut and fastens the ball stud to the VTG lever to operatively couple the VTG lever to the actuator linkage.

An exhaust passage structure of an internal combustion includes a first merging passage, a second merging passage, and a third merging passage connecting a third gathering portion in which the exhaust gas flowing through the first merging passage and the exhaust gas flowing through the second merging passage gather and a turbine of a turbocharger. The first merging passage and the second merging passage have respective narrowed portions in which passage cross-sectional areas are minimized. When a total value of passage cross-sectional areas of inlets of exhaust ports in one cylinder is set as a reference passage cross-sectional area A, and the passage cross-sectional areas of the narrowed portions of the first merging passage and the second merging passage are set as narrowed cross-sectional areas B, the exhaust passage structure is configured such that the relationship of 0.5≤(B/A)≤1 is established.

An engine assembly includes: a two-stroke internal combustion engine; a turbocharger operatively connected to the engine, the turbocharger having a compressor and an exhaust turbine; an intake pipe fluidly connected to the engine and to the compressor of the turbocharger; an exhaust tuned pipe fluidly connected to the engine and to the exhaust turbine of the turbocharger; a temperature sensor configured to generate a signal representative of a temperature of exhaust gas flowing within the exhaust tuned pipe; and a controller. The controller is configured to: determine a boost target pressure of the turbocharger based in part on the signal generated by the temperature sensor; and control the turbocharger to provide the boost target pressure to the engine. Methods for controlling an engine are also provided.

An engine assembly includes: a two-stroke internal combustion engine; a turbocharger operatively connected to the engine, the turbocharger having a compressor and an exhaust turbine; an intake pipe fluidly connected to the engine and to the compressor of the turbocharger; an exhaust tuned pipe fluidly connected to the engine and to the exhaust turbine of the turbocharger; a temperature sensor configured to generate a signal representative of a temperature of exhaust gas flowing within the exhaust tuned pipe; and a controller. The controller is configured to: determine a boost target pressure of the turbocharger based in part on the signal generated by the temperature sensor; and control the turbocharger to provide the boost target pressure to the engine. Methods for controlling an engine are also provided.

A method for controlling a speed of a turbocharger that is in operative connection with a compressor, the steps including: provision of a setpoint for the speed of the turbocharger on the basis of a model-based precontrol for a calculation of a desired boost pressure ahead of the turbocharger; determination of an actual value for the speed of the turbocharger; control of an actuator of the turbocharger in order to compensate for the difference between the desired value and the actual value for the speed of the turbocharger. A main signal and a subsidiary signal are provided during the determination of the actual value for the speed of the turbocharger, wherein the main signal and the subsidiary signal are combined in order to validate the actual value for the speed of the turbocharger.