Patent ID: 8096754
Filing Date: 2012-01-17
Classification: F01D,F02B,F05D,Y02T

Abstract:
1. An exhaust turbocharger having a twin scroll type turbine housing which has two exhaust gas entrance channels and two exhaust gas bypass passages which connect the two exhaust gas entrance channels to an exhaust outlet passage of the twin scroll type turbine housing, thereby bypassing two scroll passages, the two scroll passages for guiding exhaust gas entering the twin scroll type turbine housing from the two exhaust gas entrance channels to a turbine rotor of the exhaust turbocharger, the exhaust turbocharger comprising: a waste gate valve for opening/closing the two exhaust gas bypass passages, the waste gate valve having a plate-like valve body and a lever, wherein the plate-like valve body seats against and departs from a seat face formed at an outlet end side of the two exhaust gas bypass passages including an end face of a partition wall partitioning the two exhaust gas bypass passages, wherein the plate-like valve body is a disk-shaped valve, wherein the lever is attached at a surface of the plate-like valve body opposite to a seat-side face of the plate-like valve body, the lever for positioning the plate-like valve body to seat against and depart from the seat face of the twin scroll type turbine housing, wherein the seat-side face of the plate-like valve body has a conical depression such that a whole region of the end face of the partition wall does not contact the seat-side face, the conical depression having an apex at a center part thereof at which a maximum gap is formed, and wherein a predetermined gap is formed between the conical depression and the whole region of the end face of the partition wall such that only an outer periphery part of the plate-like valve body is seated against the seat face of the twin scroll type turbine housing when the waste gas valve closes the two exhaust gas bypass passages.