Abstract: An exhaust turbo-supercharger having a high efficiency is provided. The exhaust turbo-supercharger includes therein an exhaust turbine housing including a spiral channel and a turbine-accommodating chamber connected to an innermost peripheral part of the spiral channel; an exhaust turbine provided in the turbine-accommodating chamber so that the axial line of the exhaust turbine is parallel to that of the spiral channel; a shaft that is concentrically connected to one side of the exhaust turbine in the axial line direction; a bearing housing disposed at the side of the exhaust turbine in the axial line direction so as to be adjacent to the exhaust turbine housing; a bearing that is provided in the bearing housing and that rotatably supports the shaft around the axial line; and a heat shield component interposed between the exhaust turbine housing and the bearing housing.

Abstract: An exhaust turbocharger with a variable-nozzle mechanism with fail-safe feature included is provided with which, even if wear of the drive ring supporting part where the supporting elements are in reciprocating sliding or rolling contact with each other under high temperature without lubrication increases, the drive ring can be supported on the nozzle mount on the second supporting part, which enables the drive ring to be always supported rightly on the nozzle mount, and to prevent the occurrence of eccentric rotation or dropping out of the drive ring due to excessive wear of the drive ring supporting part or the occurrence of reduction in engine performance due to malfunctions of the variable-nozzle mechanism such as the error in the relation between the output of the actuator and the nozzle vane opening or the occurrence of breakage of the variable-nozzle mechanism as has been experienced in prior arts.

Abstract: The improvements are made in the turbine scroll and the turbine blades. The scroll structure for the radial turbines is characterized by the foregoing scroll having a scroll width ratio between the width in the radial direction (&Dgr;R) and the width in the direction of the rotation (B) ranging from &Dgr;R/B=0.3 to 0.7. It is further characterized by the configuration in which the turbine blades have cut-away areas at the blade corners by a prescribed amount, which are provided on the inlet edge at the shroud side and hub side where the operating gas flows.

Abstract: The improvements are made in the turbine scroll and the turbine blades. The scroll structure for the radial turbines is characterized by the foregoing scroll having a scroll width ratio between the width in the radial direction (&Dgr;R) and the width in the direction of the rotation (B) ranging from &Dgr;R/B=0.3 to 0.7. It is further characterized by the configuration in which the turbine blades have cut-away areas at the blade corners by a prescribed amount, which are provided on the inlet edge at the shroud side and hub side where the operating gas flows.