A gear of a speed reducer of an actuator includes: an insert component; a center portion; an outer peripheral portion; a connecting portion; a gate mark; a weld-line portion; and a rib-shaped portion. The center portion surrounds the insert component. The outer peripheral portion includes a toothed portion and a toothless portion. The weld-line portion is formed in at least one of the center portion, the connecting portion and the outer peripheral portion at a location which is on a radially inner side of the toothless portion. The rib-shaped portion is formed in at least one of the center portion, the connecting portion and the outer peripheral portion at a location which includes the weld-line portion. The rib-shaped portion has a wall thickness that is larger than a wall thickness of another circumferential portion.

A rotary turbine bypass valve comprises a valve chamber positioned at a junction of an inlet port, an outlet port and a bypass port, the inlet port configured for fluid communication with a flow of exhaust gas from an engine, the outlet port configured for fluid communication with an inlet of a turbine, and the bypass port configured for fluid communication with an exhaust aftertreatment device; and a valve rotor supported for rotation, about a valve axis, within the valve chamber. The valve rotor is rotatable about the valve axis between a first position in which the valve rotor permits gas flow through the bypass port and a second position in which the valve rotor blocks gas flow through the bypass port. The valve rotor is eccentric such that it includes a seal portion which is a portion of the valve rotor within the valve chamber which is furthest radially spaced from the valve axis; and as the valve rotor moves from the first position to the second position the seal portion moves towards the bypass port such that the radial separation between the valve rotor and the bypass port decreases to a minimum when the valve rotor is in the second position in which the seal portion is adjacent the bypass port.

An actuator includes an electric motor, an output shaft and a speed reducer. The speed reducer includes at least one metal gear which has a plurality of teeth made of metal. The speed reducer is configured to transmit rotation, which is outputted from the electric motor, to the output shaft after reducing a rotational speed of the rotation. The actuator includes a housing that receives the electric motor and the speed reducer. The actuator includes a plate member that is configured to limit scattering of a scattering object, which is generated in response to an operation of the speed reducer and is scattered from the at least one metal gear.

Systems, methods and apparatus are disclosed for providing or maintaining a target surge margin at the compressor during steady state engine operating conditions and to avoid compressor surge during transients by controlling a compressor recirculation valve position to a commanded position. The estimated surge margin can be determined in response to the measured pressure ratio across the compressor, an estimated compressor flow, and a compressor map for the compressor.

Systems, methods and apparatus are disclosed for providing or maintaining a target surge margin at the compressor during steady state engine operating conditions and to avoid compressor surge during transients by controlling a compressor recirculation valve position to a commanded position. The estimated surge margin can be determined in response to the measured pressure ratio across the compressor, an estimated compressor flow, and a compressor map for the compressor.

A system and method of controlling a turbocharged engine system includes receiving a boost mode selection signal and controlling the turbocharged engine system in response to the boost mode selection signal.

Systems and methods for operating an engine that is started via expansion stroke combustion are described. In one example, the method increases air flow through the engine during an engine stopping process so that a larger amount of air may be trapped in a cylinder that is on its expansion stroke so that greater amounts of engine torque may be provided during engine starting.

Methods and systems are provided for a turbocharger. In one example, a method may include bypassing exhaust gases flowing to the turbocharger in response to a catalyst temperature being less than a threshold temperature. The bypassing includes opening a bypass valve and adjusting a position of one or more turbine nozzle vanes.

Methods and systems are provided for a turbocharger. In one example, a method may include bypassing exhaust gases flowing to the turbocharger in response to a catalyst temperature being less than a threshold temperature. The bypassing includes opening a bypass valve and adjusting a position of one or more turbine nozzle vanes.

An exhaust gas-conducting section of an exhaust turbocharger comprises a duct with a through-flow opening which can be fully or at least partially blocked or released by a closure element of a control device. The closure element is designed as a poppet valve. The closure element can be moved by an actuator can be disposed in a wall of the exhaust gas-conducting section. The closure element has a closure body with an annular section surface on its bottom surface which faces the through-flow opening. The section surface corresponds to an element seat formed in the wall. Its top surface faces away from the bottom surface and is designed in a profiled manner in order to produce a top surface at least partially corresponding to another element seat and/or to achieve flow-optimized circulation.