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.

Abstract: A ported-shroud 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, and the ring opens the ported shroud. In the closed position, the ring abuts the tapering surface to close off the annular passage and to close off the ported shroud. 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 variable-geometry orifice actuated by a rotatable actuator ring. In the closed position, the orifice's inner diameter is smaller than that of a shroud surface of the compressor housing and therefore dictates the effective inlet diameter for the compressor. In the open position the orifice no longer forms an inner diameter smaller than the shroud surface, so that the effective inlet diameter is determined by the shroud surface.

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 variable-geometry orifice actuated by a rotatable actuator ring. In the closed position, the orifice's inner diameter is smaller than that of a shroud surface of the compressor housing and therefore dictates the effective inlet diameter for the compressor. In the open position the orifice no longer forms an inner diameter smaller than the shroud surface, so that the effective inlet diameter is determined by the shroud surface.

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 ported-shroud 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, and the ring opens the ported shroud. In the closed position, the ring abuts the tapering surface to close off the annular passage and to close off the ported shroud. 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.

Abstract: Various embodiments of ported-shroud centrifugal compressors are described. In some embodiments a wall of a compressor housing defines a pair of bulb-shaped hollow spaces or “bulbs”, one located proximate the compressor wheel and the other spaced upstream from the wheel, and having a connection therebetween. The downstream bulb is connected to the main flow path of the compressor by a port slot through the wall. The upstream bulb is connected to the inlet area of the main flow path by a passage through the wall. The bulbs can provide acoustic wave cancellation through multiple internal reflections in various directions. In one embodiment, the upstream bulb has a second passage connected to it, facing axially upstream, for receiving a portion of the total flow in a choked-flow operating regime, and conducting that portion through the upstream bulb, through the connection to the downstream bulb, and through the port slot into the main flow path.

Abstract: Various embodiments of ported-shroud centrifugal compressors are described. In some embodiments a wall of a compressor housing defines a pair of bulb-shaped hollow spaces or “bulbs”, one located proximate the compressor wheel and the other spaced upstream from the wheel, and having a connection therebetween. The downstream bulb is connected to the main flow path of the compressor by a port slot through the wall. The upstream bulb is connected to the inlet area of the main flow path by a passage through the wall. The bulbs can provide acoustic wave cancellation through multiple internal reflections in various directions. In one embodiment, the upstream bulb has a second passage connected to it, facing axially upstream, for receiving a portion of the total flow in a choked-flow operating regime, and conducting that portion through the upstream bulb, through the connection to the downstream bulb, and through the port slot into the main flow path.