Abstract: A method for controlling an inlet-adjustment mechanism in an air inlet for a compressor so as to switch the mechanism in a binary fashion between open and closed positions for adjusting a flow area of the inlet. The method includes identifying a threshold line on a compressor map of pressure ratio versus corrected flow rate for the compressor, at which the inlet-adjustment mechanism is switched from one of its positions to the other. A fixed switch band straddling the threshold line can be used for determining when to initiate the switch of positions so as to time the switch to coincide with the operating point reaching the threshold line. Alternatively, a time to reach the threshold line can be instantaneously computed and compared to the actuator/mechanism response time.

Abstract: A turbocharger having a divided turbine housing scroll includes separate first and second exhaust gas conduits for feeding separate streams of exhaust gas to two separate scrolls in the turbine housing. A cross-scroll communication control valve in the turbine housing is operable to selectively allow or prevent two separate streams of exhaust gas in the turbine housing to fluidly communicate with each other. The valve member rotates about a valve axis that is parallel to a flow axis along with the exhaust gas flows in the exhaust gas conduits. The valve member tapers in the flow direction. In a first position, the valve member has walls that close off a cross-communication opening between the two exhaust gas conduits, thereby isolating the conduits from each other. In a second position, a through-passage of the valve member becomes aligned with the cross-communication opening to allow cross-talk between the two conduits.

Abstract: A method for controlling an inlet-adjustment mechanism in an air inlet for a compressor so as to switch the mechanism in a binary fashion between open and closed positions for adjusting a flow area of the inlet. The method includes identifying a threshold line on a compressor map of pressure ratio versus corrected flow rate for the compressor, at which the inlet-adjustment mechanism is switched from one of its positions to the other. A fixed switch band straddling the threshold line can be used for determining when to initiate the switch of positions so as to time the switch to coincide with the operating point reaching the threshold line. Alternatively, a time to reach the threshold line can be instantaneously computed and compared to the actuator/mechanism response time.

Abstract: A turbocharger includes a turbine wheel mounted within a turbine housing and connected to a compressor wheel by a shaft. The turbine housing defines an exhaust gas inlet connected to a volute that surrounds the turbine wheel, and an axial bore through which exhaust gas that has passed through the turbine wheel is discharged from the turbine housing. The turbine housing further defines an annular bypass passage surrounding the bore and arranged to allow exhaust gas to bypass the turbine wheel. An annular bypass valve is disposed in the bypass passage. The bypass valve comprises a fixed annular valve seat and a rotary annular valve member arranged coaxially with the valve seat. A catalyst is disposed in the annular bypass passage. The catalyst is formed of spaced-apart, undulating metal fins coated with a catalyst material and contained in a generally annular cage.