Variable geometry exhaust turbocharger and method of manufacturing

摘要

According to the present invention, the A/R, the ratio of cross sectional area A of scroll passage to scroll radius R can be increased without increasing the size of the turbine casing and with very simple construction and exhaust turbine capacity can be increased, so a variable-throat exhaust turbocharger with which engine output can be increased is provided. The turbocharger is equipped with a nozzle throat area varying mechanism of which the nozzle assembly unit is composed such that a plurality of nozzle vanes are supported rotatably by an annular nozzle mount and an annular nozzle plate is connected to the nozzle mount by means of a plurality of nozzle supports to sandwich the nozzle vanes, the nozzle plate is located in the scroll chamber by attaching the nozzle assembly unit to the turbine casing to allow the nozzle plate to form part of the inside sidewall face of the scroll chamber and a wall face of the annular flow passage.