Abstract: A turbocharger (100) has an asymmetric, twin scroll volute design, having a first volute (101) and a larger second volute (102). The larger second volute (102) eliminates the need for a wastegate and its associated actuator. The smaller first volute (101) is sized for rapid transients and rated torque, while the second volute (102) is sized such that the turbine inlet pressure is satisfactory for rated power. Furthermore, the turbocharger (100) preferably incorporates a mixed flow turbine wheel (108) rather than a radial wheel, which allows for a larger wheel size to be used while still maintaining inertia. The turbine housing (103) is improved wherein the first and second volutes (101) and (102) 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 (112).

Abstract: A turbocharger (100) has an asymmetric, twin scroll volute design, having a first volute (101) and a larger second volute (102). The larger second volute (102) eliminates the need for a wastegate and its associated actuator. The smaller first volute (101) is sized for rapid transients and rated torque, while the second volute (102) is sized such that the turbine inlet pressure is satisfactory for rated power. Furthermore, the turbocharger (100) preferably incorporates a mixed flow turbine wheel (108) rather than a radial wheel, which allows for a larger wheel size to be used while still maintaining inertia. The turbine housing (103) is improved wherein the first and second volutes (101) and (102) 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 (112).