Systems and methods for controlling turbocharger operation by maintaining a virtual turbocharger speed calculation using airflow parameters in the context of an engine. An example uses a turbocharger speed estimator, an energy observer, and an energy controller. Optimization of turbocharger speed control, including avoidance of overspeed, while reducing wastegate actuation, can be achieved using a predictive control algorithm.

The present application relates to an abnormality determination device for a variable geometry turbocharger having a nozzle mechanism capable of changing a flow path area of exhaust gas with an actuator. The abnormality determination device includes: a first detection part configured to be capable of detecting at least one of a load of the actuator or supply energy to the actuator; and a determination part configured to determine that an abnormality is present, if a detection result by the first detection part is out of an allowable range corresponding to an operational state of the variable geometry turbocharger.

A variable geometry turbocharger according to an embodiment includes a rotational shaft; a turbine wheel disposed on one end side of the rotational shaft; a compressor wheel disposed on another end side of the rotational shaft; a bearing housing for housing a bearing part for rotatably supporting the rotational shaft; a variable nozzle structure for controlling a flow rate of an exhaust gas flowing into the turbine wheel, the variable nozzle structure including a nozzle plate and nozzle mount that define an exhaust gas flow passage for allowing the exhaust gas to flow into the turbine wheel, a nozzle vane disposed rotatably about a support shaft in the exhaust gas flow passage, and a drive part for rotating the nozzle vane, the drive part being disposed in an internal space defined between the bearing housing and the nozzle mount; and a cooling gas passage for extracting compressed gas compressed by the compressor wheel and introducing the compressed gas into the internal space.

A variable geometry turbocharger according to an embodiment includes a rotational shaft; a turbine wheel disposed on one end side of the rotational shaft; a compressor wheel disposed on another end side of the rotational shaft; a bearing housing for housing a bearing part for rotatably supporting the rotational shaft; a variable nozzle structure for controlling a flow rate of an exhaust gas flowing into the turbine wheel, the variable nozzle structure including a nozzle plate and nozzle mount that define an exhaust gas flow passage for allowing the exhaust gas to flow into the turbine wheel, a nozzle vane disposed rotatably about a support shaft in the exhaust gas flow passage, and a drive part for rotating the nozzle vane, the drive part being disposed in an internal space defined between the bearing housing and the nozzle mount; and a cooling gas passage for extracting compressed gas compressed by the compressor wheel and introducing the compressed gas into the internal space.

The invention concerns a method for controlling a compression release brake mechanism in an combustion engine comprising an air inlet system and an exhaust manifold connected to a turbocharger provided with a variable turbine geometry (VTG) turbine, said exhaust manifold further comprising an exhaust gas recirculation (EGR) channel for recirculation of exhaust gas towards the air inlet system, wherein said turbine is further connected to a back pressure valve (BPV) provided in an exhaust channel, the method comprising determining a desired exhaust manifold gas pressure level on the basis of a measured engine speed and a desired braking torque; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling said BPV and said VTG by said control parameters, to drive one of the control parameters to a set maximum level; and controlling the EGR by said control parameters in a closed loop to allow exhaust gas to recirculate towards the air inlet system while driving a second of the set of control parameters to a set maximum level.

The invention concerns a method for controlling a compression release brake mechanism in an combustion engine comprising an air inlet system and an exhaust manifold connected to a turbocharger provided with a variable turbine geometry (VTG) turbine, said exhaust manifold further comprising an exhaust gas recirculation (EGR) channel for recirculation of exhaust gas towards the air inlet system, wherein said turbine is further connected to a back pressure valve (BPV) provided in an exhaust channel, the method comprising determining a desired exhaust manifold gas pressure level on the basis of a measured engine speed and a desired braking torque; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling said BPV and said VTG by said control parameters, to drive one of the control parameters to a set maximum level; and controlling the EGR by said control parameters in a closed loop to allow exhaust gas to recirculate towards the air inlet system while driving a second of the set of control parameters to a set maximum level.

A wastegate valve for a bypass path for a turbocharger in an internal combustion engine, the wastegate valve comprises a valve seat defining a plane which is non-orthogonal to the principal flow axis for gases flowing along the bypass path and a valve member pivotable from an open position to a closed position, wherein in the closed position the valve member is seated on the valve seat, and in a fully open position the valve member is positioned to direct gases exiting the bypass path onto a leading face of a catalytic converter monolith for heating the monolith.

A turbine for a turbo-machine is proposed in which, at a gas inlet for a turbine wheel, vanes extend from a nozzle ring though slots in a shroud. The nozzle ring and shroud are relatively rotatable about a rotational axis of the turbine by at least 0.1 degrees. In use, the nozzle ring and shroud are relatively rotated to bring one side of the vane into close contact with one surface of the slot, to inhibit leakage of gas between the vane and the slot surface. For this purpose the respective surfaces of the nozzle and slot can be configured to closely conform to each other. If there is differential thermal expansion of the shroud and nozzle ring, the nozzle ring and shroud can relatively rotate, to withdraw the vane from the edge of the slot to relieve the pressure between them.

A method for activating a boost pressure control for an internal combustion engine, which contains, in a through-flow direction, a compressor, a charge air line, a throttle valve, an intake manifold, at least one combustion chamber and a turbine speed-coupled to the compressor, an aperture of the throttle valve being controllable, a driving of the turbine being controllable by an exhaust gas flow, and the method including: predefining a setpoint intake manifold pressure; calculating a simplified inverse flow characteristic of the throttle valve; calculating a pseudo setpoint aperture of the throttle valve, based on the simplified inverse flow characteristic and the setpoint intake manifold pressure; and controlling the driving of the turbine, based on an exceeding of a maximum aperture of the throttle valve by the pseudo setpoint aperture of the throttle valve.

A method for activating a boost pressure control for an internal combustion engine, which contains, in a through-flow direction, a compressor, a charge air line, a throttle valve, an intake manifold, at least one combustion chamber and a turbine speed-coupled to the compressor, an aperture of the throttle valve being controllable, a driving of the turbine being controllable by an exhaust gas flow, and the method including: predefining a setpoint intake manifold pressure; calculating a simplified inverse flow characteristic of the throttle valve; calculating a pseudo setpoint aperture of the throttle valve, based on the simplified inverse flow characteristic and the setpoint intake manifold pressure; and controlling the driving of the turbine, based on an exceeding of a maximum aperture of the throttle valve by the pseudo setpoint aperture of the throttle valve.