Abstract: A turbocharger comprises a turbine wheel and a compressor wheel mounted to a turbocharger shaft. An electric induction motor is provided for assisting rotation of the compressor wheel in predetermined circumstances. The motor comprises a fixed stator having motor field coils which generate a rotating magnetic field when energised by an AC control signal which induces eddy current flow in a rotor to generate a rotor magnetic field which in turn interacts with the stator magnetic field producing torque in the rotor.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: A compressor comprises an impeller (1) provided with a plurality of radial blades (4). The impeller (1) has an inducer diameter defined by the outer diameter of front edges (5) of the blades (4), and an outer diameter defined by the outer diameter of the blade tips (6). Each blade (4) is backswept relative to the direction of rotation of the impeller (1) with an angle of backsweep in the range 45° to 55°. The ratio of the impeller inducer diameter to the impeller outer diameter is in the range 0.59 to 0.63. The ratio of the compressor diffuser outlet diameter to the impeller outer diameter is between 1.4 and 1.55.

Abstract: An actuator rod (17) for a turbocharger pressure control assembly comprises a first elongate portion (17a) defining a first rod end and a second portion (17b) defining a second rod end. The first and second portions are pivotally joined to one another to allow a degree of relative pivotal motion therebetween in at least one plane perpendicular to the axis of said elongate first portion (17a).

Abstract: A variable geometry turbine comprises a housing defining a chamber within which a turbine wheel is mounted. The chamber has an annular inlet having a width defined between side walls of the housing. An array of vanes is mounted within the inlet, each vane having a length extending across the inlet, and a chordal length defined between leading and trailing vane edges. The vanes can be pivoted to adjust the effective cross-section area of the annular inlet. Each vane is pivotable between a first position in which the area of the inlet is a minimum and a second position in which the area of the inlet is a maximum. At least one of the side walls is configured so that clearance between the side wall and at least a portion of the adjacent chordal edge of each vane varies in a predetermined manner as the vane moves.

Abstract: A control system for an exhaust brake which operates to impede exhaust flow from a turbocharged combustion engine when the engine throttle is closed. The control system includes means for delaying application the exhaust brake only when the vehicle throttle is closed to allow the rotational speed of the turbo charger to drop thereby reducing wear to seal components.

Abstract: A turbocharger comprises a turbine wheel and a compressor wheel mounted to a turbocharger shaft. An electric induction motor is provided for assisting rotation of the compressor wheel in predetermined circumstances. The motor comprises a fixed stator having motor field coils which generate a rotating magnetic field when energised by an AC control signal which induces eddy current flow in a rotor to generate a rotor magnetic field which in turn interacts with the stator magnetic field producing torque in the rotor.

Abstract: A compressor for compressing a gas comprises an impeller wheel (1) mounted within a housing (2) defining an inlet and an outlet (6). The inlet comprises an outer tubular wall (7) extending away from the impeller wheel in an upstream direction and forming a gas intake portion (8) of the inlet, and an inner tubular wall (9) of diameter D extending away from the impeller wheel in an upstream direction within the outer tubular wall (7) and defining an inducer portion (10) of the inlet. An annular gas flow passage (11) is defined between the inner and outer tubular walls (9, 7) and has an upstream end and a downstream end separated by a length L1 measured along its axis. The upstream end of the annular passage (11) communicates with the intake or inducer portions of the inlet through at least one upstream aperture and at least one downstream aperture (13) communicates between a downstream portion of the annular flow passage (11) and the impeller.

Abstract: A wastegated turbocharger includes a turbine wheel mounted to a shaft for rotation within a turbine housing and a compressor wheel mounted to the shaft for rotation within a compressor housing. The compressor housing has mounted thereto a wastegate actuator command valve. A secondary boost air outlet passage is disposed in fluid flow communication with the wastegate actuator command valve and the compressor outlet volute. The secondary boost air outlet passage extends into the compressor outlet volute so that an inlet opening of the passage is spaced from the surface of the compressor outlet volute.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: A variable geometry turbocharger comprises a turbine wheel (20) mounted within a turbine housing (23) on one end of a turbocharger shaft (22) for rotation about a turbocharger axis. The turbine housing (23) defines an annular turbine inlet (36) around the turbine wheel (20). A compressor wheel (21) is mounted within a compressor housing (24) on the other end of the turbocharger shaft (22). Turbocharger shaft bearing assemblies (26, 27) are located within a bearing housing (25) connected between the turbine housing (23) and the compressor housing (24). A variable geometry mechanism (35) is provided for varying the size of the annular turbine inlet (36). The variable geometry mechanism is actuated by a tubular linear electric motor comprising a fixed annular stator ring (31a, 46, 48) and an axially moveable annular forcer ring (44), arranged coaxially about the turbocharger axis.

Abstract: A turbocharger variable geometry turbine of the type which includes nozzle vanes displaceable across the turbine inlet flow path into slots. The vanes have cut-outs which reduce the vane cord and permit peak turbine efficiency over a range of geometries.

Abstract: A turbocharger having a turbine wheel mounted to a seal boss at one end of a shaft and a compressor wheel mounted to the other end of the shaft. The seal boss includes an annular face angled relative to a radial plane extending through the shaft so that as the shaft rotates oil present on the annular face is projected into an oil collecting groove in a direction radially away from the shaft and axially away from an annular passage in a housing wall.

Abstract: A compressor for compressing a gas comprises an impeller wheel (1) including a plurality of vanes (4) rotatably mounted within a housing (2). The housing (2) has an inner wall defining a surface (5) located in close proximity to radially outer edges (4a) of impeller vanes (4). The compressor inlet comprises an outer tubular wall (7) extending forming a gas intake and an inner tubular wall (8) extending within the outer tubular wall (7) and defining an inducer portion (10) of the inlet. An annular gas flow passage (11) is defined between the inner and outer tubular walls. There is at least one downstream aperture (13) communicating between the annular flow passage (11) and the surface (5) of the housing (2) swept by the impeller vanes (4) and at least one upstream aperture communicating between the annular flow passage (11) and the inducer or intake portions of the inlet.

Abstract: A compressor comprises a compressor wheel (8) mounted for rotation within a compressor housing (4,5), which an annular outlet passage (15) defined between opposing annular wall surfaces. A portion (20) of at least one of the wall surfaces is resiliently flexible such that operational pressure changes within the outlet passage (15) cause the resilient wall surface portion to flex.

Abstract: A turbocharger comprises a compressor wheel (7) assembled to one end of a turbocharger shaft (8). A nut (17) is threaded on to the end of the shaft (8) to clamp the wheel (7) on the shaft to prevent both axial movement of the wheel (7) along the shaft (8) and rotational slippage. The torque capacity of the coupling between the compressor wheel (7) and nut (17) is increased by treating contacting surfaces of the coupling to increase their co-efficient of friction.

Abstract: A compressor wheel assembly comprises a compressor wheel (7) mounted to a rotating shaft (8), which extends through a bore provided along the rotational axis of the wheel (7). The wheel (7) is keyed to the shaft (8) such that rotation of the shaft (8) drives rotation of the wheel through the keying engagement.

Abstract: A control system for an exhaust brake which operates to impede exhaust flow from a turbocharged combustion engine when the engine throttle is closed. The control system includes means for delaying application the exhaust brake only when the vehicle throttle is closed to allow the rotational speed of the turbo charger to drop thereby reducing wear to seal components.

Abstract: A variable geometry turbine having a inlet passageway defined between a moveable wall member and a radial wall. The moveable wall member is moveable to vary the width of the inlet passageway. At least one bypass passage is formed in one of the moveable wall member and an adjacent annular cavity surface. Upon the moveable wall member and a seal being moved axially relative to one another the bypass passage permits the flow of exhaust gas around the inlet passageway.

Abstract: A turbine comprises a turbine wheel having radial blades and supported in a housing for rotation about an axis. An annular inlet passageway extends radially inwards towards the turbine wheel, the inlet passageway being defined between first and second facing annular walls. An annular array of vanes extend across the inlet passageway. Each vane has a trailing edge extending adjacent the turbine wheel blades, wherein the trailing edge of each vane deviates from a straight line over at least a portion of its length defined between its ends.