Method for manufacturing heat resisting member applicable to an exhaust gas guide assembly with improved heat resistance for VGS turbocharger

Abstract

An exhaust gas guide assembly with an improved high-temperature wear resistance, oxidation resistance, high-temperature strength or the like for a VGS turbocharger is provided. According to the invention, the exhaust gas guide assembly for a VGS turbocharger includes adjustable blades, a turbine frame and an adjusting mechanism is characterized in that a heat resisting member constitutes the exhaust gas guide assembly to remarkably enhance high-temperature durability or the like of the exhaust gas guide assembly.

Description

[0001]This is a Continuation application of application Ser. No. 10 / 476,789, filed May 14, 2004, which is a National Stage of PCT / JP02 / 04552, filed May 10, 2002, the contents of which are incorporated herein in their entirety.TECHNICAL FIELD[0002]The present invention relates generally to a turbocharger for use in an automobile engine or the like, and more particularly to an exhaust gas guide assembly incorporated therein and an adjustable blade that is a component thereof.BACKGROUND ART[0003]A turbocharger is known as a supercharger used as means for improving the power output and the performance of an automobile engine. The turbocharger is an apparatus in which a turbine is driven by the exhaust energy of the engine to rotate a compressor with the power of the turbine, whereby the engine is supercharged to have more air fed into it than fed into it by natural suction. The turbocharger, when the engine is running at a low rotational speed, can not avoid giving a slow-moving feeling...

AI Technical Summary

Benefits of technology

[0009]An exhaust gas guide assembly, with an improved heat resistance, for a VGS turbocharger includes adjustable blades for suitably controlling the flow rate of exhaust gas discharged from an engine to rotate an exhaust turbine wheel; a turbine frame which rotatably supports the adjustable blades at the outside of an outer periphery of the turbine wheel; and an adjusting mechanism for suitably rotating the adjustable blades to control the flow rate of the exhaust gas. The flow of the exhaust gas at a low flow rate is throttled by the adjustable blades to increase the velocity of the exhaust gas so that a high output power is obtained at low rotational speeds. The assembly is characterized in that a heat resisting metal member constituting the exhaust gas guide assembly has a cleanliness level which is set to be not more than 0.1% in the area ratio of nonmetallic inclusions.

Problems solved by technology

The turbocharger, when the engine is running at a low rotational speed, can not avoid giving a slow-moving feeling caused by the reduced flow rate of the exhaust gas and continued until the exhaust turbine runs efficiently, and necessitating a subsequent time or a so-called turbo-lag before the turbine rapidly reaches the full-running state.

Furthermore, in the case of a diesel engine which runs inherently at low rotational speeds, there is a disadvantage that it is difficult to produce an effect of the turbocharger.

However, since the assembly is used under very severe conditions, its life or durability has a certain limit.

However, it is very difficult to obtain a shaped material having a near-net shape for the adjustable blade in a conventional precision casting method or metal injection molding method, and such current techniques have not reached a stage where adjustable blades can be actually mass-produced at a stable and high level.

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