Methods and systems for adjusting a branch communication and wastegate valve in a dual scroll turbocharger system are provided. In one example, a method may include adjusting the branch communication and wastegate valve in a passage connecting a first scroll, a second scroll, and a wastegate passage may control an amount of exhaust flow to a turbine during certain engine operating conditions.

Control techniques for a turbocharger of an engine utilize a wastegate valve configured to divert exhaust gas from a turbine of the turbocharger that is rotatably coupled to a compressor of the turbocharger. A controller is utilized to obtain a torque request for the engine, determine a target compressor power based on the engine torque request, determine a normalized target turbine power based on the target compressor power, determine a target position for the wastegate valve based on the normalized target turbine power and a normalized exhaust flow, and actuate the wastegate valve to the target position. Such control techniques involve the actual calculation of much less intermediate parameters, such as target turbine pressure ratio, which results in more efficient calibration and implementation.

An internal combustion engine includes a twin entry type turbocharger with which a first exhaust passage and a second exhaust passage respectively communicate individually, a communication path that causes the first exhaust passage and the second exhaust passage to communicate with each other, a communication valve that opens and closes the communication path, an abnormality diagnosis device that diagnoses presence or absence of abnormality of the communication valve, a variable valve timing mechanism capable of changing a period of valve overlap of the engine, and a control device. When it is determined that abnormality of a valve closure failure of the communication valve is present, the control device operates the mechanism to reduce the valve overlap in an operating state in which the communication valve is closed, more than in a case where it is determined that abnormality of a valve closure failure of the communication valve is absent.

An internal combustion engine includes a twin entry type turbocharger with which a first exhaust passage and a second exhaust passage respectively communicate individually, a space forming section that communicates with the first exhaust passage via a first communication path, and communicates with the second exhaust passage via a second communication path, a communication control valve that opens and closes the first communication path and the second communication path, and a drive mechanism that is connected to a valve body of the communication control valve and drives the valve body to open and close the valve body. The drive mechanism is provided at a side of the space forming section with respect to the valve body in a state where the valve body is closed.

A shut-off member for a turbocharger for an internal combustion engine includes a first channel, a second channel, and a wall that separates the first channel from the second channel. A shut-off member opening is formed in the wall that connects the first channel and the second channel. The shut-off member opening is selectively openable and closable by a shut-off member body. A cooling channel is disposed in the wall and at least partially surrounds the shut-off member opening.

A turbine housing defining a pair of volutes with respective outlets divided by a divider wall, includes a diffuser space in the gas flow path between the volutes and the turbine wheel. The diffuser space has an upstream portion having a smaller axial extent than a downstream portion of the diffuser space. The widening of the diffuser space tends to direct exhaust gas entering the diffusion space from at least one side of the divider wall towards the corresponding axial end of the diffuser space. Thus reduces the tendency of this gas to interrupt the flow into the diffuser space of exhaust gas from the other inlet volute.

A turbocharger is provided with an improved bearing which is formed as a floating ring bearing or a semi-floating ring bearing having a conical or hemispherical shape which supports both journal and thrust loads. The floating ring bearing may have conical floating ring bearings (70), (100), (180) that define inner and outer conical bearing surfaces (71), (108), (185) and (72), (109), (186) which cooperate on the inside with corresponding conical journals (75/76), (111/112), (187/188) that rotate with the shaft (53), and cooperate on the outside with a stationary bearing housing (52) to form inner and outer fluid films. Alternatively, the floating ring bearing may have a pair of hemispherical floating ring bearings (85), (140), (210) that have hemispherical inner and outer bearing surfaces (86), (144), (211) and (87), (145), (212) which form inner and outer fluid films. A semi-floating ring bearing may also be provided with these structures.

A method for operating an internal combustion engine is provided. The method includes during a first operating condition, operating two primary cylinders and two secondary cylinders to perform combustion, the two primary and secondary cylinders arranged in an inline configuration, the two primary cylinder adjacent to one another, the two secondary cylinders adjacent to one another, and the secondary cylinders positioned 175°-185° out of phase relative to the two primary cylinders and during a second operating condition, selectively deactivating the two secondary cylinders to perform combustion in only the two primary cylinders.

Different attack angles including a first attack angle and a second attack angle are set to turbine blades on a first axial side and a second axial side according to respective relative inflow angles of an exhaust gas. In other words, the first attack angle is set on the first axial side according to a relative inflow angle of an exhaust gas blown against the turbine blades through a first scroll passage, and the second attack angle is set on the second axial side according to a relative inflow angle of an exhaust gas blown against the turbine blades through a second scroll passage. An average value of the first attack angle is larger than an average value of the second attack angle.

A supercharged internal combustion engine has cylinder groups with plural cylinders and plural exhaust gas turbochargers. Exhaust gas can be fed to at least one first exhaust gas turbocharger from first outlet valves of the cylinders of the first and second cylinder groups via at least one first exhaust manifold. Exhaust gas can be fed to at least one second exhaust gas turbocharger from second outlet valves of cylinders of the first and second cylinder groups via a second exhaust manifold. At low rotational speeds and/or in part load and/or non-steady state operation, exhaust gas can be fed via the first exhaust manifolds that are connected to the first outlet valves per cylinder group to a turbine of the first exhaust gas turbocharger in flows that can be divided in the inflow region of the turbine, while the second exhaust gas turbocharger is inactive.