Asymmetric twin scroll volute

Abstract

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.