VARIABLE GEOMETRY TURBINE

摘要

A variable geometry turbine comprising an annular inlet surrounding a turbine wheel mounted for rotation about a turbine axis within a turbine chamber defined by a housing. The chamber has an annular inlet defined between inboard and outboard inlet side walls and surrounding the turbine wheel. The annular inlet includes: a first pair of first and second circumferentially spaced inlet passages; and a second pair of third and fourth circumferencially spaced inlet passages. The second pair of inlet passages is axially displaced from the first pair of inlet passages and a cylindrical sleeve is supported within the housing for reciprocal motion in an axial direction to vary the size of the annular inlet. The sleeve is movable between at least a first position in which each of the first pair of inlet passages is at least partially open to gas flow, and the second pair of inlet passages are fully open to gas flow, and a second position in which the first pair of inlet passages are fully blocked to the gas flow and each of the second pair or inlet passages is at least partial!/ blocked to gas flow.