Abstract: A turbocharger compressor includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The mechanism includes a plurality of movable blades disposed about the compressor air inlet and located between an upstream wall surface and a downstream wall surface of an annular space within the air inlet wall. The blades move radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Recirculation of air upstream through the mechanism is prevented by a downstream blade seal. When EGR is employed, an upstream blade seal is included, preventing oil-laden air from migrating into the mechanism. The blade seals can be of various types, including O-ring seals or labyrinth seals.

Abstract: A method for controlling an inlet-adjustment mechanism in an air inlet for a compressor so as to switch the mechanism between open and closed positions for adjusting a flow area of the inlet. The method includes an algorithm for determining when the inlet-adjustment mechanism is in a failure mode. In accordance with the method, when the operating point on the compressor map is on the high-flow side of a threshold line at which the inlet-adjustment mechanism is switched from one position to the other, a measured speed or pressure ratio is compared to a theoretical value for the speed or pressure ratio based on a compressor map for the open position of the mechanism. If the measured value differs from the theoretical value by more than a predetermined tolerance, a failure mode is indicated.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of blades disposed about the air inlet and each pivotable about one end of the blade, the blades extending through a slot in the air inlet wall when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

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 centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The inlet-adjustment mechanism includes a plurality of blades disposed about the compressor air inlet and located within an annular space within the air inlet wall. The blades are pivotable about respective pivot points such that the blades extend radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Upstream surfaces of the blades include swirl inducers that are structured and arranged to impart either pre-swirl or counter-swirl to the air passing through the orifice into the compressor wheel.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The inlet-adjustment mechanism includes a plurality of blades disposed about the compressor air inlet and located within an annular space within the air inlet wall. The blades are pivotable about respective pivot points such that the blades extend radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. The blades include lever arms that engage the outer periphery of a rotatable unison ring that is linked to a linear actuator for rotating the unison ring so as to pivot the blades.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The inlet-adjustment mechanism includes a plurality of blades disposed about the compressor air inlet and located within an annular space within the air inlet wall. The blades are pivotable about respective pivot points such that the blades extend radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Downstream surfaces of the blades include vortex reducers that are structured and arranged to reduce a strength of an unsteady vortex generated from the radially inner edges of the blades.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of first blades disposed about the air inlet and each pivotable about one end of the blade, and a plurality of second blades axially adjacent to the first blades and disposed about the air inlet and each pivotable about one end of the blade, the first and second blades extending through a slot in the air inlet wall when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of blades disposed about the air inlet and collectively circumscribing an orifice, the blades being movable inwardly through a slot in the air inlet wall so as to adjust the size of the orifice. Compressor performance is optimized through selection of inlet-adjustment mechanism parameters including the minimum orifice area when closed ARc, spacing distance L between the minimum-area point and the compressor wheel leading edge, blade shape, and orifice shape.

Abstract: A turbocharger compressor includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The mechanism includes a plurality of movable blades disposed about the compressor air inlet and located between an upstream wall surface and a downstream wall surface of an annular space within the air inlet wall. The blades move radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Recirculation of air upstream through the mechanism is prevented by a downstream blade seal. When EGR is employed, an upstream blade seal is included, preventing oil-laden air from migrating into the mechanism. The blade seals can be of various types, including O-ring seals or labyrinth seals.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism operable to move between an open position and a closed position. The inlet-adjustment mechanism includes a plurality of blades disposed about the compressor air inlet and located between an upstream wall surface and a downstream wall surface of an annular space within the air inlet wall. The blades are pivotable about respective pivot points such that the blades extend radially inward from the annular space into the air inlet when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Aerodynamic pressure balancing across the blades is achieved by spacing features that space a majority of the upstream surface of each blade from the opposing upstream wall surface.

Abstract: A centrifugal compressor for a turbocharger includes a passive inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position solely by aerodynamic forces on the mechanism. The inlet-adjustment mechanism includes a plurality of flexible vanes collectively forming a duct, and an effective diameter of the air inlet at the inducer portion of the compressor wheel is determined by a trailing edge inside diameter of the duct. The vanes are movable solely by aerodynamic forces exerted on the vanes by the air flowing to the compressor wheel. The duct has a tapering configuration when the vanes are in a relaxed state, but under aerodynamic force the vanes flex outwardly and increase the trailing edge inside diameter of the duct, thereby increasing an effective diameter of the air inlet.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between a closed position, an open position, and a super-open position. The compressor also includes a ported shroud system. The inlet-adjustment mechanism includes a plurality of blades disposed about the air inlet and movable radially inwardly and outwardly for defining the various positions. In the closed position, the effective diameter of air inlet is reduced and the blades block flow through the ported shroud system. In the open position, the blades still block the ported shroud but the effective inlet diameter is increased relative to the closed position. In the super-open position, the blades unblock the ported shroud so that an additional amount of flow can pass through the ported shroud, thereby shifting the compressor's choke flow line to higher flow rates.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of vanes formed as ring segments and disposed about the air inlet and each movable circumferentially and radially inwardly through a slot in the air inlet wall so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

Abstract: A centrifugal compressor for a turbocharger includes a passive inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position solely by aerodynamic forces on the mechanism. The inlet-adjustment mechanism includes a plurality of flexible vanes collectively forming a duct, and an effective diameter of the air inlet at the inducer portion of the compressor wheel is determined by a trailing edge inside diameter of the duct. The vanes are movable solely by aerodynamic forces exerted on the vanes by the air flowing to the compressor wheel. The duct has a tapering configuration when the vanes are in a relaxed state, but under aerodynamic force the vanes flex outwardly and increase the trailing edge inside diameter of the duct, thereby increasing an effective diameter of the air inlet.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a variable-geometry conical mechanism comprising a plurality of vanes that in the closed position collectively form a frusto-conical inlet member having a trailing edge inner diameter that is smaller than an inner diameter of the shroud surface of the compressor housing at the inducer portion of the compressor wheel such that an effective diameter of the air inlet at the inducer portion is determined by the trailing edge inner diameter of the variable-geometry conical mechanism. The vanes in the open position are pivoted radially outwardly so as to increase the trailing edge inner diameter of the inlet member and thereby increase the effective diameter of the air inlet at the inducer portion.

Abstract: A centrifugal compressor for a turbocharger includes a passive or semi-passive inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position solely by aerodynamic forces on the mechanism. The inlet-adjustment mechanism includes a plurality of flexible vanes collectively forming a duct, and an effective diameter of the air inlet at the inducer portion of the compressor wheel is determined by a trailing edge inside diameter of the duct. The vanes are movable solely or in part by aerodynamic forces exerted on the vanes by the air flowing to the compressor wheel. The duct has a tapering configuration when the vanes are in a relaxed state, but under aerodynamic force the vanes flex outwardly and increase the trailing edge inside diameter of the duct, thereby increasing an effective diameter of the air inlet.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of first blades disposed about the air inlet and each pivotable about one end of the blade, and a plurality of second blades axially adjacent to the first blades and disposed about the air inlet and each pivotable about one end of the blade, the first and second blades extending through a slot in the air inlet wall when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes a plurality of blades disposed about the air inlet and each pivotable about one end of the blade, the blades extending through a slot in the air inlet wall when the blades are in the closed position so as to form an orifice of reduced diameter relative to a nominal diameter of the inlet. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

Abstract: A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes an axially elongated ring. In the open position, the radially outer surface of the ring is spaced from a tapering inner surface of the air inlet so that air can flow in an annular passage between the tapering surface and the ring. In the closed position, the ring abuts the tapering surface to close off the annular passage, whereby the effective inlet diameter is then defined by the inner diameter of the ring at its trailing edge. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.