Sector-Divided Turbine Assembly With Axial Piston Variable-Geometry Mechanism

Abstract

A turbine (40) for a turbocharger (10) has a turbine housing (41) defining a generally annular chamber (43) surrounding a turbine wheel (44), the chamber receiving exhaust gas for driving the turbine wheel. The chamber has dividing walls (46) that divide the chamber into a plurality of angular sectors (43a,43b), each fed with exhaust gas separately from the other sector(s). (52,53) located radially inwardly of the sectors for guiding flow into the turbine wheel include at least dividing vanes (52) that form extensions of the dividing walls (46) so as to extend the sector-division of the exhaust gas flow path all the way to the trailing edges of the dividing vanes. An axially slidable piston (48) is disposed radially inwardly of the sectors, and radially overlaps with the dividing vanes (52). The vanes either are mounted on fixed structure and are received in slots (49) in the piston, or are mounted on the piston and received in slots in fixed structure.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field[0002]The invention relates to turbochargers in which a turbine of the turbocharger is driven by exhaust gas from a reciprocating engine. The invention relates more particularly to turbine housings that are divided into a plurality of substantially separate sections each fed by a separate exhaust system, and to turbochargers having a variable-geometry turbine for controlling the flow into the turbine.[0003]2. Description of Related Art[0004]In multiple-piston reciprocating engines, it is known to design the exhaust system in such a manner as to take advantage of the pressure pulsation that occurs in the exhaust stream. In particular, it is known to employ what is known as “pulse separation” wherein the cylinders of the engine are divided into a plurality of subgroups, and the pulses from each subgroup of cylinders are substantially isolated from those of the other subgroups by having independent exhaust passages for each subgroup. T...

AI Technical Summary

Benefits of technology

The invention relates to turbochargers for engines that use multiple pistons and a sector-divided turbine housing. The technical effect of the invention is to integrate the benefits of sector division and variable geometry in a turbocharger to optimize performance over a range of engine operating conditions. The invention also includes a compressor assembly, center housing and bearing assembly, and a turbine assembly. The compressor assembly includes a compressor housing with an axially extending air inlet and a compressor wheel mounted on a rotatable shaft. The turbine assembly includes a turbine housing divided into angular sectors each with a piston and guide vane. The invention allows for separate exhaust passages for each sector to minimize the communication or "cross talk" between the sectors.

Problems solved by technology

In known prior turbochargers having sector division and variable geometry, the full benefits of sector division generally have not been achieved; in fact, the benefits of sector division and variable geometry each have been compromised when such integration has been attempted.

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