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 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 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 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 in which a drive shaft supports at one end a turbine driven by exhaust gases from an internal combustion engine. The end of the drive shaft remote from the turbine supports a drive connection which is coupled to an output shaft of the driving engine. The shaft is supported in a housing by a first bearing adjacent the turbine and a second bearing adjacent the drive coupling. The first and second bearings each define an inner bearing surface relative to which the shaft rotates and an outer bearing surface which rotates relative to the housing. The first and second bearings are mechanically coupled together such that they rotate relative to the housing at the same speed. Coupling the two bearings together ensures that directional forces applied to the bearing at the end adjacent the drive connection which might cause that bearing to seize are resisted by torque delivered from the bearing at the other end of the shaft.

Abstract: A control system for a variable geometry turbocharger having a turbine driven by exhaust gas delivered to an exhaust gas inlet of the turbocharger from an engine exhaust manifold and a compressor driven by the turbine to deliver air to an engine intake manifold via an air outlet of the turbocharger. The differential pressure across the engine is monitored, and a closed loop control system adjusts the variable geometry mechanism to prevent the differential pressure exceeding a predetermined limit. In engine braking mode the variable geometry mechanism may be actuated by a signal representative of the exhaust manifold pressure. An override circuit may be provided to control the variable geometry mechanism in the event of the turbocharger rpm exceeding a predetermined limit.

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 compressor comprises a housing (4, 5) defining an inlet (6) and an outlet (15, 7), and a compressor wheel (8) mounted for rotation about a shaft (9a) within a chamber defined by the housing between the inlet (6) and the outlet (7). The back of the compressor wheel (8) is set into a recess (16) defined by a wall of said housing (4), the outside diameter of the recess (16) being greater than the outside diameter of the recessed portion (10) of the compressor wheel (8) defining an annular clearance gap around the recessed portion of the compressor wheel (8). The outside diameter of the recess (16) is at least 1.05 times the outside diameter of the recessed portion of the compressor wheel and/or the depth of the recess in the region of said gap is greater than 1.5 times the axial width of the recessed portion of the compressor wheel.

Abstract: A turbocharger comprises a compressor wheel (6) mounted within a compressor housing (5) having a pressurized air outlet, a control valve (12) for regulating the pressure of air supplied from the compressor housing outlet, and pressure operated actuating means (13) mounted to the turbocharger for actuating the control valve. The actuator comprises a case (16) defining a pressure chamber and an inlet for delivering pressure to the chamber, and a substantially rigid connecting pipe (23) of well defined shape extending from the actuator inlet to the compressor housing (5). The end of the connecting pipe (23) remote from the case (16) communicates with the compressor outlet to deliver pressure to the actuator inlet.

Abstract: A linkage mechanism for linking for example actuator rods to the nozzle ring of a variable geometry turbine. First and second components of the mechanism are interconnected by at least two links which are displaceable in a predetermined direction relative to the first component and connected at spaced apart locations to the second component. At least one of the links incorporates an element which is pivotal relative to the first component about a first axes and pivotal relative to the second component about a second axis, the two axis being parallel to each other, parallel to the predetermined direction, and offset relative to each other.

Abstract: A centripetal compressor includes a compressor housing, a compressor wheel mounted within the housing and having compressor blades. The compressor housing comprises a cover plate and a diffuser flange that is fixed to both the cover plate and to a bearing housing. The diffuser member has an outer peripheral portion attached to the cover plate and a radially inner portion attached to the bearing housing. A frangible groove or weakened section is defined in the diffuser at a position intermediate the outer peripheral and the radially inner portions so as to enable predictable fracture of the diffuser flange during failure of the compressor wheel. The same principle is applied to the turbine of a turbocharger.

Abstract: A variable geometry turbocharger for an internal combustion engine in which the position of the nozzle ring is adjusted to control the width of an exhaust gas inlet passage. A chamber is defined behind the nozzle ring which communicates with the inlet passage and the pressure within that chamber is monitored. The monitored pressure is used as a control parameter for a mechanism which displaces the nozzle ring. Positioning a sensor in the recess behind the nozzle ring protects the sensor from the relatively more extreme environment within the engine exhaust gas manifold.

Abstract: A centripetal turbine (1) comprises a housing (3) and a turbine wheel (4) mounted within the housing (3) and having turbine blades (5). The housing (3) defines an annular inlet passageway (7) arranged around a portion of the turbine wheel (4), and an outlet passageway (8) which has a generally cylindrical portion arranged around a portion of the turbine wheel (4). The housing (3) also defines a curved annular shoulder (9) curving radially outwards from the generally cylindrical portion of the outlet passageway (8) to the annular inlet passageway (7). The radially outer edge of each turbine blade (5) has a first portion (11) adjacent the generally cylindrical portion of the outlet passageway (8), and a second curved portion (12) adjacent the curved annular shoulder (9).

Abstract: A variable geometry turbine comprising a housing, a turbine wheel mounted to rotate about a pre-determined axis within the housing, and a gas inlet passage to the turbine. The gas inlet passage is defined between a fixed wall and an annular sidewall which is mounted in the housing and is displaceable relative to the fixed wall between axially spaced first and second positions. The sidewall is biased away from the fixed by at least one spring towards the first position, an axial force is applied to the sidewall in opposition to the spring to thereby control the axial position of the sidewall. The spring or springs provide a non-linear length to spring force characteristics such that the resultant of the applied spring force and an axial force applied to the sidewall as a result of gas flow through the passage increases continuously as the sidewall is displaced from the first position to the second position.

Abstract: A turbocharger in which a turbine wheel located in a turbine chamber is driven by an exhaust gas flow. A bypass passageway extends around the chamber to enable exhaust gas to be diverted away from the turbine wheel. A valve is mounted in the bypass passageway and controlled so as to selectively open and close the passageway. The passageway opens into the exhaust gas outlet in a direction such that gas issuing from the passageway is directed in a substantially annular form and in a substantially downstream direction.

Abstract: A variable geometry turbine comprising a housing 1 including an annular cavity 19 which supports a moveable annular wall member 5. An annular turbine inlet passageway 4 is defined between an end face of the moveable wall member 5 and a facing wall 6 of the housing 1. The moveable wall member 5 is moveable so as to vary the width of the annular turbine inlet passageway 4. Gas tight seals 20, 21 are provided between the wall member 5 and radially inner and outer surfaces of the cavity 19 and apertures 24 are provided through the face of the annular wall member 5. The arrangement is such that the mean pressure difference between the cavity 19 and the annular turbine inlet passageway 4 is reduced so that the total axial load on the wall member 5 due to gas flow through the inlet passageway 4 is reduced.

Abstract: A flexible coupling has an inner member and a resilient body mounted on the hub and connected thereto. A reinforcement ring is embedded within the resilient body. The ring has arcuately spaced tubes with tapered rubber liners. Fasteners for connecting the coupling to the flywheel are locatable within the rubber liners. The taper causes the fixing to induce a precompression in the rubber tubes when the coupling is assembled and fitted in place. The coupling minimizes backlash, provides extra torsional flexibility and permits blind assembly.

Abstract: A torsional vibration damper in which variable volume chambers pump oil through restricted passages in response to relative torsional movement between a driven and inertia member in the damper. The passages are connected to radially inner and outer sides of an annular spring. Torsional oscillation causes the spring to deflect in a circumferential direction and the restricted passages damp the vibration.