JPH10274048A - Variable capacity turbocharger - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent a long distance until engine exhaust blown from a variable nozzle enters a turbine wheel, thereby preventing loss during that time from increasing. SOLUTION: In a variable displacement turbocharger in which a variable nozzle is provided in a turbine rotated by exhaust of an engine, the turbine has a plurality of movable vanes 7 constituting a variable nozzle arranged around an outer periphery of a turbine impeller 2. Each movable vane 7 is rotatably provided around a shaft 8 disposed on the downstream end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement turbocharger in which a variable nozzle is provided in a turbine rotated by the exhaust of an engine.

[0002]

2. Description of the Related Art A turbine of a variable displacement turbocharger has a turbine wheel rotatably provided in a housing, and movable vanes 17 are arranged at equal intervals around the turbine wheel 12 as shown in FIG. The movable vanes 17 adjacent to each other constitute a variable nozzle.

[0003] The opening area of the variable nozzle of the turbine is increased or decreased in accordance with the exhaust flow rate of the engine, the supercharging efficiency of the turbocharger is increased, and the output characteristics of the engine are improved.

When the exhaust flow rate of the engine is small, the movable vanes 17 are arranged substantially in the circumferential direction of the turbine wheel 12 and the downstream ends of the movable vanes 17 are respectively connected to the movable vanes 17 as shown by solid lines in FIG. In the vicinity of the upstream end of the movable vane 17 adjacent to the downstream side, the opening of the variable nozzle is narrowed, and the driving power of the turbine and hence the driving power of the compressor are increased even if the exhaust flow rate of the engine is small.

When the exhaust flow rate of the engine is large, FIG.
As shown by a chain line, each movable vane 17 is arranged substantially in the radial direction of the turbine wheel 12, and the downstream end of each movable vane 17 is moved away from the movable vane 17 adjacent to the downstream side of the movable vane 17, respectively. The opening of the variable nozzle is widened to suppress a rise in the turbine inlet pressure and hence the engine exhaust pressure even when the engine exhaust flow rate is large.

[0006]

However, in the variable displacement turbocharger turbine as described above,
As shown in FIG. 6, the rotatable movable vane 17 has its shaft 18 disposed at an intermediate position between the upstream end and the downstream end. Therefore, when the opening of the variable nozzle becomes narrow, the opening of the variable nozzle is The distance from the inlet of the turbine impeller 12 to the upstream side and the engine exhaust ejected from the variable nozzle to enter the turbine impeller 12 becomes longer, and the loss during that time increases. Therefore, the efficiency of the turbine is reduced, and the supercharging efficiency of the turbocharger is reduced.

The movable vanes are sandwiched between both side walls of the housing which are deformed by the heat of the engine exhaust. There is a wide gap between them. Therefore, the amount of engine exhaust leaking from the wide gap is large, the efficiency of the turbine is reduced, and the supercharging efficiency of the turbocharger is reduced.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a variable displacement turbocharger in which a variable nozzle is provided in a turbine rotated by the exhaust of an engine. A plurality of movable vanes were arranged, and each movable vane was provided rotatably around an axis arranged at the downstream end thereof.

More specifically, in the turbine, fixed vanes and movable vanes constituting a variable nozzle are alternately arranged around a turbine wheel rotatably provided in a housing, and each fixed vane is placed on both sides of the housing. The movable vanes were fixed between the wall portions, and each movable vane was rotatably provided around an axis disposed on the downstream end side of the movable vane between both side wall portions of the housing.

[0010]

In the turbine of the present invention, the movable vane rotates around an axis disposed on the downstream end side, so that the variable nozzle opening becomes narrower or wider.
The opening position of the variable nozzle does not fluctuate greatly, and the distance until the engine exhaust ejected from the variable nozzle enters the turbine wheel does not increase, and the loss during that time does not increase.

When the fixed vanes and the movable vanes are alternately arranged and each fixed vane is fixed between both side walls of the housing, the distance between the both side walls of the housing sandwiching the movable vane is fixed vane. Is held. Therefore, even if the gap between each side wall of the housing and the movable vane is narrowed,
It is possible to prevent the movable vane from becoming unrotatable due to thermal deformation of the housing. The gap between each side wall of the housing and the movable vane can be narrowed to reduce the amount of engine exhaust leaking from the gap.

After all, in the variable displacement turbocharger of the present invention, the efficiency of the turbine is high and the supercharging efficiency is high.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A variable displacement turbocharger
A compressor is interposed in an intake passage connected to a cylinder of an automobile engine, a turbine is interposed in an exhaust passage connected to the cylinder, and the compressor and the turbine are coaxially connected.

The exhaust gas flowing through the exhaust passage of the engine rotates the turbine to rotate the compressor. The air flowing through the intake passage of the engine is compressed by the compressor, and the high-pressure air is supplied to the cylinder of the engine.

As shown in FIG. 1, a turbine wheel 2 is placed in the center of a housing 1 and the turbine wheel 2
Shaft 3 is mounted on the rear part of the housing 1, a spiral chamber 4 is provided on the outer peripheral part of the housing 1, and a large-diameter part of the spiral chamber 4 is connected to an exhaust inlet pipe (not shown). A tube 5 is provided.

[0016] Between the turbine wheel 2 and the swirl chamber 4, there is shown in FIG.
As shown in FIG. 2 and FIG. 2, the same number of fixed vanes 6 and movable vanes 7 are arranged at equal intervals along the intermediate direction between the radial direction and the circumferential direction of the turbine wheel 2, respectively.
And the movable vanes 7 are alternately arranged, and each fixed vane 6 is fixed between the front and rear side walls of the housing 1.
Between the movable vanes 7 and the side walls of the housing 1 is narrowed, and the shaft 8 protruding from the downstream end side surface of each movable vane 7 is set in the housing. 1, each movable vane 7 is provided rotatably around a shaft 8 disposed at the downstream end side thereof,
The shaft 8 of each movable vane 7 is arranged at a position close to the adjacent fixed vane 6 on the downstream side, and the adjacent fixed vane 6 and movable vane 7 constitute a variable nozzle.

Although the gap between the movable vane 7 and each side wall of the housing 1 is set to be small, the distance between the both side walls of the housing 1 is held by the fixed vane 6, so that the housing 1 is heated. Even if deformed, the movable vane 7 is prevented from becoming unrotatable.

The front end of the shaft 8 of each movable vane 7 projecting out of the housing 1, as shown in FIG.
Is linked to a mechanism 9 for interlocking and tilting, and an interlocking tilting mechanism 9
And a control device for controlling the drive device in accordance with the exhaust flow rate of the engine and hence the rotational speed of the engine.

When the exhaust flow rate of the engine is small, as shown in FIG. 3, each movable vane 7 is arranged substantially in the circumferential direction of the turbine wheel 2, and the upstream end of each movable vane 7 is located upstream of the movable vane 7 respectively. The movable vane 7 is closed to the downstream end of the movable vane 7 by contacting the downstream end of the fixed vane 6 adjacent to the movable vane 6 to close the gap between each movable vane 7 and the fixed vane 6 adjacent to the upstream thereof. The opening of the variable nozzle is narrowed in the vicinity of the fixed vane 6 adjacent to the nozzle, and the driving power of the turbine is increased even if the exhaust flow rate of the engine is small.

When the exhaust flow rate of the engine is large, FIG.
As shown in FIG. 5, each movable vane 7 is disposed substantially in the radial direction of the turbine wheel 2, and each movable vane 7 is brought into contact with the upstream end of the fixed vane 6 adjacent to the downstream side of the movable vane 7 so that each movable vane 7 is moved. The gap between the vane 7 and the fixed vane 6 adjacent to the downstream side thereof is closed, and the upstream end of each movable vane 7 is moved away from the fixed vane 6 adjacent to the upstream side of the movable vane 7 to widen the opening of the variable nozzle. Even when the exhaust flow rate of the engine is large, the rise in the turbine inlet pressure is suppressed.

As is clear from FIG. 3 and FIG. 4, the opening position of the variable nozzle does not fluctuate greatly even if the opening of the variable nozzle becomes narrow or wide, and the engine exhaust blown from the variable nozzle is discharged from the turbine blade. The distance to the car 2 does not become long, and the loss during that time does not increase.

Further, since the gap between each side wall of the housing 1 and the movable vane 7 is set to be small, the amount of engine exhaust leaking from the gap is small.

As a result, the efficiency of the turbine is high. As shown in FIG. 5, in the variable displacement turbocharger of the present invention, the supercharging efficiency is higher than in the conventional example shown in FIG. In particular, when the exhaust flow rate of the engine is small, the supercharging efficiency is high.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a turbine of a variable displacement turbocharger according to an embodiment of the present invention.

FIG. 2 is a partial vertical sectional front view of the turbine.

FIG. 3 is a partial vertical sectional front view showing a state where an opening of a variable nozzle of the turbine is narrowed.

FIG. 4 is a partial vertical sectional front view showing a state where an opening of a variable nozzle of the turbine is widened.

FIG. 5 is a diagram showing the relationship between the supercharging efficiency and the exhaust gas flow rate of the variable displacement turbocharger.

FIG. 6 is a partial longitudinal front view of a turbine of a conventional variable displacement turbocharger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Turbine wheel 6 Fixed vane 7 Movable vane 8 Movable vane shaft

Continuing from the front page (72) Inventor Akinobu Bessho 41 No. 41, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory Co., Ltd. Inside the corporation

Claims (1)

[Claims] 1. A variable displacement turbocharger in which a variable nozzle is provided on a turbine rotated by exhaust gas of an engine, wherein the turbine has a plurality of movable vanes constituting a variable nozzle disposed around an outer periphery of a turbine wheel. A variable displacement turbocharger, wherein each movable vane is rotatably provided around an axis disposed at a downstream end thereof.