Abstract: A compressor comprises a housing having an axial intake and an annular outlet volute. An impeller is mounted on a shaft for rotation about a shaft axis between the axial intake and the annular outlet volute. The impeller has a plurality of blades, each blade having a front edge facing the axial intake and a tip. The annular outlet volute includes an annular diffuser passage surrounding the impeller. The annular diffuser passage has a diffuser inlet downstream of the plurality of blades and a diffuser outlet communicating with the annular outlet volute, the tips of the blades sweeping across said diffuser inlet during use. A wall of the housing which defines the annular diffuser passage and which extends over the front edges of the blades defines an annular recess extending from the diffuser inlet towards the diffuser outlet.

Abstract: A compressor comprises a compressor housing, a compressor wheel mounted within the housing and having compressor blades, and a bearing housing. The compressor housing comprises a cover member and a diffuser member that is connected to both the cover member and the bearing housing. The diffuser member has a radially outer portion connected to the cover member and a radially inner portion connected to the bearing housing. The diffuser member has a first weakened region defined at a first position intermediate the radially outer portion and the radially inner portion, and a first strengthened region defined at a second position intermediate the radially outer portion and the radially inner portion, said second position being radially inwards or outwards of the first weakened region.

Abstract: A variable geometry turbine having a turbine wheel, an inlet passageway, a movable wall member being moveable axially to vary the width of the inlet passageway, an annular seal being mounted to the movable wall member or an adjacent housing member to provide a seal between adjacent surfaces of the movable wall member and housing member respectively, wherein a bypass passage is provided in the other of said movable wall member or housing member, extending from an inlet bypass port to an outlet bypass port, said ports being spaced from each other and provided in said adjacent surface of said other of the movable wall member or housing member, arranged such that as the movable wall member moves axially, the annular seal moves axially relative to the ports to vary the flow that may pass from a region of the cavity inboard of the seal, through the bypass passage.

Abstract: A sensing apparatus for a turbomachine comprises: a magnet; a sensing coil; a power supply; and a processor. The magnet is arranged to produce a magnetic field and the sensing coil is at least partially disposed in the magnetic field. The power supply is operable to provide a voltage across the sensing coil. The processor is operable to determine a periodicity of a voltage across the sensing coil. The processor is further operable to determine a quantity indicative of temperature dependent characteristic of the sensing coil.

Abstract: A method for manufacturing a turbine wheel comprising casting the turbine wheel from an austenitic nickel-chromium-based superalloy, subjecting the cast turbine wheel to hot isostatic pressing and then subjecting a surface of the hot isostatically pressed turbine wheel to plastic deformation, wherein said hot isostatic pressing is effected at a pressure of 98 to 200 MPa and a temperature of 1160 to 1220° C. for a time period of 225 to 300 minutes. There is further described a hot isostatically pressed cast turbine wheel manufactured from an austenitic nickel-chromium-based superalloy, the turbine wheel having a plastically deformed surface; and a turbocharger incorporating such a turbine wheel.

Abstract: A turbine housing has a cavity that defines a turbine axis, and has a volute. The volute comprises a volute passage spiralling radially inwards towards the cavity, a substantially annular throat positioned around the cavity between it and the volute passage, and a tongue terminating at a distal tongue tip. In a plane containing the turbine axis and the tongue tip, the throat defines a line of minimum clearance, the volute passage and tongue tip co-operatively define a preliminary inlet area, and the tongue tip defines a tongue tip lateral centerline. The line of minimum clearance and the preliminary inlet area co-operatively define a line of passage offset, which connects the centroid of the preliminary inlet area and a point half way along the line of minimum clearance. The line of passage offset is not perpendicular to the turbine axis, and the tongue tip lateral centerline and the line of passage offset define an angle therebetween of at least 60 degrees.

Abstract: A mixed-flow turbine wheel is proposed which, compared to existing mixed-flow turbine wheels, has reduced mass and moment of inertia because radially-outer portions of existing mixed-flow turbine wheels are omitted. In a first possibility, the omitted material may be scalloping of the back face of the turbine wheel at a radial position outward of a base line which is a circle on the back surface of the wheel which indicates the minimum radius of the back surface. In a second possibility, part of the webbing of each blade is omitted to one side of the blade. Thus, viewing the turbine wheel in the axial direction, the area of the webbing outside the baseline and to one side of a radial line through the inducer tip, may be at least 20% less than that on the other side.

Abstract: A variable geometry turbine assembly comprising an inlet passageway, extending radially inwards towards a turbine wheel, defined between a surface of a movable wall member and a facing wall and an actuation mechanism arranged to move the movable wall member axially and comprising a cam member provided with at least one formation and a carrier member axially coupled to at least one co-operating formation, wherein one of the at least one formation and the at least one co-operating formation is a radially extending formation, the at least one formation or the at least one co-operating formation extending in both the circumferential direction and the axial direction such that as the cam member is rotated relative to the carrier member, the at least one formation and the at least one co-operating formation engage such the movable wall member is moved in the axial direction.

Abstract: A turbine for a turbo-machine is proposed in which, at a gas inlet, vanes, extending from a nozzle ring though slots in a shroud, are shaped on one side to as to substantially conform to the profile of the surface of the slot, whereby a close connection can be formed between the vane and the slot to inhibit leakage of gas between the vane and the slot surface.

Abstract: A method for manufacturing a turbine wheel comprising casting the turbine wheel from an austenitic nickel-chromium-based superalloy, subjecting the cast turbine wheel to hot isostatic pressing and then subjecting a surface of the hot isostatically pressed turbine wheel to plastic deformation, wherein said hot isostatic pressing is effected at a pressure of 98 to 200 MPa and a temperature of 1160 to 1220° C. for a time period of 225 to 300 minutes. There is further described a hot isostatically pressed cast turbine wheel manufactured from an austenitic nickel-chromium-based superalloy, the turbine wheel having a plastically deformed surface; and a turbocharger incorporating such a turbine wheel.

Abstract: A diffuser is proposed which is formed as the gap between rotationally-symmetric surfaces which face each other. Moving in the radial direction, the axial extent of the gap generally decreases to a minimum value in a throat portion of the diffuser, and then generally increases again. The distance from the rotational axis of the compressor to the throat may be approximately at least 125% of the radius of the compressor wheel. The inventors have found that a throat at this distance from the rotational axis may lead to higher efficiency at high flow rates, especially for relatively low turbo speeds. This is because the spacing between the compressor wheel and the throat permits diffusion of the gas streams leaving the compressor wheel.

Abstract: A seal assembly for restricting fluid leakage flow through a fluid leakage cavity defined between a first component and second component that is rotatable about an axis relative to the first component, the seal assembly having a fluid jet outlet configured to admit a fluid jet into the fluid leakage cavity in an upstream direction which is inclined to the axis, a first flow restriction located downstream of the fluid jet outlet and at a location such that the fluid jet admitted from the fluid jet outlet would impinge on the first flow restriction once the fluid jet has turned to flow in an axial direction, and a second flow restriction located downstream of the first flow restriction. An axial flow turbine having a turbine rotor mounted within a housing may incorporate such a seal assembly in a fluid leakage cavity defined between the turbine rotor and the housing.

Abstract: A turbomachine having an axial stop member arranged to restrain axial movement of a bearing assembly of the turbomachine, the axial stop member having a bore defined by a radially inner surface of the axial stop member which forms a close radial fit with a shaft of the turbomachine, or a member mounted on the shaft to rotate with the shaft, an anti-rotation formation engageable with a complimentary formation provided on an outer race of the bearing assembly so as to rotationally fix the outer race relative to the axial stop member and wherein the axial stop member further comprises a lubricating fluid directing member and a lubricating fluid outlet, the lubricating fluid directing member being arranged to receive lubricating fluid that is flung radially outward from said axis, due to the rotation of the shaft, and to direct the lubricating fluid to the lubricating fluid outlet.

Abstract: A method of manufacturing a compressor housing is provided including arranging a core with a die to define a mould cavity, solidifying a metal within the cavity to form a compressor housing having a diffuser first wall and an outlet volute first wall with an opening; the housing being formed such that a first angle is subtended between an outlet section of a surface of the diffuser first wall and a first section of a surface of the outlet volute first wall, wherein after the housing has been formed, the core is removed and a cut is applied, through the opening, to the first section of the surface of the outlet volute first wall to produce a cut section such that a second angle is subtended between the cut section and the outlet section of the surface of the diffuser first wall that is greater than the first angle.

Abstract: A variable geometry turbine comprising a turbine wheel mounted for rotation about a turbine axis within a housing. The housing defines an annular inlet surrounding the turbine wheel and defined between first and second inlet sidewalls. The turbine further comprises a cylindrical sleeve that is axially movable across the annular inlet to vary the size of a gas flow path through the inlet. The annular inlet is divided into at least two axially offset inlet passages. The inner diameter of the sleeve is greater than the inner diameter of the inlet passages.

Abstract: A turbocharger system is provided having a compressor wheel and a turbine wheel connected by a shaft; a conduit configured to deliver a flow of lubricant to a bearing which supports the shaft, the conduit being provided with a valve; a sensor configured to monitor a speed of rotation of the shaft; and a controller configured to operate the valve to substantially stop the flow of lubricant to the bearing in response to detection of deceleration of the shaft and the speed of the shaft dropping below a threshold.

Abstract: A turbomachine comprising a turbomachine shaft for rotation about an axis and for supporting a turbine wheel at one end of the turbomachine shaft; and a bearing housing having a wall defining a bore in which the turbomachine shaft is received with a substantially annular clearance, the turbomachine shaft being supported for rotation in the bore by at least one journal bearing located within the annular clearance. A surface of the turbomachine shaft which radially underlies the or each journal bearing has a surface roughness (Ra) of less than 0.15 microns and the or each journal bearing comprises a bronze alloy incorporating bismuth in an amount of up to around 6 wt %.

Abstract: A method for manufacturing a turbine wheel comprising casting the turbine wheel from an austenitic nickel-chromium-based superalloy, subjecting the cast turbine wheel to hot isostatic pressing and then subjecting a surface of the hot isostatically pressed turbine wheel to plastic deformation, wherein said hot isostatic pressing is effected at a pressure of 98 to 200 MPa and a temperature of 1160 to 1220° C. for a time period of 225 to 300 minutes. There is further described a hot isostatically pressed cast turbine wheel manufactured from an austenitic nickel-chromium-based superalloy, the turbine wheel having a plastically deformed surface; and a turbocharger incorporating such a turbine wheel.

Abstract: A turbine comprises a turbine housing defining a turbine inlet upstream of a turbine wheel and a turbine outlet downstream of the turbine wheel; a wastegate passage connecting the turbine inlet and the turbine outlet; and a wastegate valve comprising a movable valve member. The wastegate valve has an open state and a closed state. The valve member is mounted to an actuation member passing through an actuator conduit of the turbine housing, and movable so as to move the wastegate valve between the open and closed states. The turbine further comprises a sealing arrangement configured to provide a seal arranged to substantially prevent gas from passing from the turbine outlet into the actuator conduit. The sealing arrangement is configured such that when the valve member is urged into the closed state by the actuator member the sealing effectiveness of the sealing arrangement is increased.

Abstract: A variable geometry turbine has annular inlet passageway defined between a first surface of a radial wall of a movable wall mounted within a cavity and a facing wall of the turbine housing. The radial wall defines a second surface that opposes the first surface. The moveable wall member comprises an annular flange that extends axially into the cavity and supports a radial flange defining opposing third and fourth surfaces. The radial flange seals against an annular sleeve in the cavity to define a first area within the cavity which includes the radial second and third surfaces and a second area within the cavity which includes the radial fourth surface. The first and second areas are in fluid communication with regions of the annular inlet passageway which are respectively upstream and downstream of a radial vane passage.