Borgwarner Inc.

Gregory David Uhlenhake

Matthew Brian Cooley

A turbocharger () has an asymmetric, twin scroll volute design, having a first volute () and a larger second volute (). The larger second volute () eliminates the need for a wastegate and its associated actuator. The smaller first volute () is sized for rapid transients and rated torque, while the second volute () is sized such that the turbine inlet pressure is satisfactory for rated power. Furthermore, the turbocharger () preferably incorporates a mixed flow turbine wheel () rather than a radial wheel, which allows for a larger wheel size to be used while still maintaining inertia. The turbine housing () is improved wherein the first and second volutes () and () are asymmetric with respect to each other and preferably, are leaned toward the bearing housing to match the axial component of the mixed flow turbine wheel inducer ().

Mixed flow twin scroll turbocharger with single valve

An asymmetric twin scroll turbinecombined with an integrated exhaust manifold cylinder headmay be designed to accommodate mixed, radial or axial flow turbines. The asymmetric twin scroll turbineincludes a first scrolland second scrollwherein the first scrollis larger and has greater mass flow capacity than the second scroll. The larger volute increases flow capacity and counteracts backpressure creating evenly balanced or equalized peak pressures and pulsations between both volutes and balancing of gas flow between cylinder sets. By equalizing peak pressures, pulsations, and gas flow between cylinder sets, engine self-ignition can be avoided in the cylinder set that would have had the largest peak pressures and pulsations. By in creasing flow capacity of the larger volute and balancing gas flow between cylinder sets, the turbine pressure differential is reduced and the engine can operate more efficiently, improving fuel economy.

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Arden, NC, United States of America

Gregory David Uhlenhake