JP2001342841A - Exhaust turbine type supercharger for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a fluid separation generating part occurring in a nozzle vane during high flow rate time and to improve exhaust turbine efficiency, by forming the nozzle vane in a circular arc shape, because angle of the nozzle vane can be set arbitrary with respect to a flow-in angle of exhaust gas, but the inlet angle of the nozzle vane is generally set according to an exhaust flow-in angle during low flow rate time so as to increase added pressure during low flow rate time of the exhaust gas, and at this set angle fluid can flow along the nozzle vane during the low flow rate time of the exhaust gas, but fluid separation occurs in an outlet part of the nozzle vane to decrease the turbine efficiency during the high flow rate time of the exhaust gas. SOLUTION: The nozzle vane is formed in a circular arc shape to reduce the fluid separation during high flow rate time of the exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape of a nozzle vane in an exhaust turbine type turbocharger for an automobile.

[0002]

2. Description of the Related Art As a shape of a nozzle vane in a conventional exhaust turbine type supercharger, a linear nozzle vane shape is reported in Japanese Patent Application Laid-Open No. 2000-8869.

[0003]

Assuming that the inflow angle of the exhaust gas flowing into the nozzle vane is θ1, θ1 is substantially constant even if the exhaust gas flow rate changes due to a change in the engine speed. On the other hand, the plurality of nozzle vanes arranged around the turbine rotor can rotate at an arbitrary angle, and when the inlet angle of the nozzle vane is θ2, a deviation occurs between θ2 and the inflow angle θ1. I do.

[0004] At a low exhaust gas flow rate at low engine speed, the exhaust gas is frequently used with the nozzle vanes closed, and the flow velocity of the exhaust fluid is small. In this state, the exhaust fluid can flow along the back side of the nozzle vane. However, when the exhaust gas flows at a high engine speed, the nozzle vane is frequently used with the nozzle vane opened, and the flow velocity of the exhaust fluid is high. For this reason, the inflow angle θ1 and the inlet angle θ2 deviate, and large separation occurs near the outlet on the back side of the nozzle vane. As a result, there is a problem that turbine efficiency is reduced.

Accordingly, an object of the present invention is to reduce fluid separation at a large flow rate.

[0006]

By making the nozzle vane arc-shaped, the deviation between the exhaust inflow angle at the time of a large flow rate and the nozzle vane inlet angle is reduced, and the fluid separation near the outlet behind the nozzle vane is reduced. .

[0007]

FIG. 1 shows an embodiment of the present invention.
Is an example of a nozzle vane arc shape.

FIG. 2 shows a conventional embodiment, and 2 is an example of a linear shape of a nozzle vane.

[0009]

When the shape of the nozzle vane is straight, the separation 3 occurs in the fluid 3 flowing along the outer edge 1a of the nozzle vane shown in FIG. 3; Flows, the fluid separation generating portion 6 is reduced, and the efficiency of the exhaust turbine 4 is improved from the first conventional example shown in FIG.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, wherein 1 is an example of a nozzle vane arc shape.

FIG. 2 is a conventional example, and 2 is an example of a nozzle vane linear shape.

FIG. 3 shows that there is a fluid separation generating section 5 generated in the nozzle vane when a streamline 3 at the time of a large exhaust gas flow flows along the nozzle vane straight section 1a.

FIG. 4 shows that the flow line 3 at the time of a large exhaust flow rate flows along the nozzle vane arc portion 1b, thereby reducing the fluid separation generating portion 6 generated in the nozzle vane.

FIG. 5 shows that the efficiency of the exhaust turbine is improved from Conventional Example 1 to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nozzle vane arc shape example, 1a ... Nozzle vane outer edge part in a linear shape, 1b ... Nozzle vane outer edge part in an arc shape, 2 ... Nozzle vane linear shape example, 3 ... Streamline at the time of a large amount of exhaust, 4 ... Exhaust turbine, 5 ... Fluid separation Large generation part, 6 ... Small part of fluid separation.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiaki Hirai 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. (Reference) 3G005 EA15 EA16 GA04 GB24 3G071 AB06 BA07 BA09 DA16 HA04

Claims (1)

[Claims] An exhaust turbine type for an automobile, wherein a nozzle vane disposed around a turbine rotor is capable of reducing an exhaust flow rate by rotating so that the nozzle vane has an arc shape. Supercharger.