Inlet duct for rearward-facing compressor wheel, and turbocharger incorporating same

摘要

A turbocharger includes a compressor wheel having back-to-back impellers (i.e., a forward-facing impeller and a rearward-facing impeller) mounted on the same shaft. The two impellers are independently supplied with inlet air via separate inlet ducts and discharge pressurized air to a common volute. The inlet duct for the rearward-facing impeller comprises a generally axially extending tubular conduit having an upstream end and a downstream end, the tubular conduit being bifurcated at the downstream end into a pair of separate duct branches that divide an air stream flowing through the tubular conduit into a pair of separate air streams. The duct branches direct the air streams radially inwardly and then re-join the streams and turn the air to an axial direction into the second impeller.