VARIABLE-GEOMETRY TURBOCHARGER WITH ASYMMETRIC DIVIDED VOLUTE FOR ENGINE EXHAUST GAS PULSE OPTIMIZATION.
First Claim
1. A turbine assembly of a turbocharger for use with an internal combustion engine having two banks of engine cylinders, each bank having multiple engine cylinders exhausting exhaust gas into an exhaust gas discharge line separate from the exhaust gas discharge line for the other bank, the turbine assembly comprising:
- a turbine housing having a bore extending in an axial direction and having a twin scroll surrounding the bore for receiving exhaust gas from the exhaust gas discharge lines of the engine, the twin scroll defining a first scroll and a second scroll that is substantially divided and separated from the first scroll, the first scroll located upstream of the second scroll with respect to an axial flow direction along which exhaust gas flows through the bore -of the turbine housing;
a turbine wheel rotatably mounted in the bore, the turbine wheel comprising a hub and a plurality of circumferentially spaced blades joined to the hub and extending generally radially outwardly therefrom and terminating in blade tips, the blades defining blade passages therebetween, each blade passage having a throat at which a flow area of the blade passage is a minimum, a radial-axial projection of the blade tips defining a contour having a first portion located axially upstream of the throat and a second portion located axially downstream of the first portion, at least part of the second portion being located axially downstream of the throat;
an exhaust gas inlet defined by the turbine housing for admitting exhaust gas into the first and second scrolls, the exhaust gas inlet being configured to place both the first and second scrolls in fluid communication with both exhaust gas discharge lines from the engine;
the first scroll having an outlet portion configured to direct exhaust gas substantially only to the first portion of the contour; and
the second scroll having an outlet portion configured to direct exhaust gas substantially only to the second portion of the contour.
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Accused Products
Abstract
A turbine assembly for a variable-geometry turbocharger includes a turbine housing defining a divided volute having first and second scrolls, wherein the first scroll has a substantially smaller volume than the second scroll. The first scroll feeds exhaust gas to a first portion of a turbine wheel upstream of the throat of the wheel, while the second scroll feeds gas to a second portion of the wheel at least part of which is downstream of the throat. Flow from the second scroll is regulated by a sliding piston. The first scroll can be optimized for low-flow conditions such that the turbocharger can operate effectively like a small fixed-geometry turbocharger when the piston is closed. The turbine housing defines an inlet that is divided by a dividing wall into two portions respectively feeding gas to the two scrolls, a leading edge of the dividing wall being downstream of the inlet mouth.
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Citations
12 Claims
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1. A turbine assembly of a turbocharger for use with an internal combustion engine having two banks of engine cylinders, each bank having multiple engine cylinders exhausting exhaust gas into an exhaust gas discharge line separate from the exhaust gas discharge line for the other bank, the turbine assembly comprising:
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a turbine housing having a bore extending in an axial direction and having a twin scroll surrounding the bore for receiving exhaust gas from the exhaust gas discharge lines of the engine, the twin scroll defining a first scroll and a second scroll that is substantially divided and separated from the first scroll, the first scroll located upstream of the second scroll with respect to an axial flow direction along which exhaust gas flows through the bore -of the turbine housing; a turbine wheel rotatably mounted in the bore, the turbine wheel comprising a hub and a plurality of circumferentially spaced blades joined to the hub and extending generally radially outwardly therefrom and terminating in blade tips, the blades defining blade passages therebetween, each blade passage having a throat at which a flow area of the blade passage is a minimum, a radial-axial projection of the blade tips defining a contour having a first portion located axially upstream of the throat and a second portion located axially downstream of the first portion, at least part of the second portion being located axially downstream of the throat; an exhaust gas inlet defined by the turbine housing for admitting exhaust gas into the first and second scrolls, the exhaust gas inlet being configured to place both the first and second scrolls in fluid communication with both exhaust gas discharge lines from the engine; the first scroll having an outlet portion configured to direct exhaust gas substantially only to the first portion of the contour; and the second scroll having an outlet portion configured to direct exhaust gas substantially only to the second portion of the contour. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification