EP3150805B1 - Variable geometry turbocharger guide vane and turbocharger - Google Patents

Description

The invention relates to a blade of a turbocharger with adjustable turbine geometry according to claim 1 and to a turbocharger according to claim 7.

Such a turbocharger is from the US 6,709,232 B1 (corresponding EP 1 534 933 A1 ) known.

From the U.S. 5,299,909 a radial turbine with a radial nozzle arrangement is known which has a plurality of blades, the blade surfaces and a blade center line having a curvature.

The advantages and success of direct injection diesel engines in terms of drivability and low consumption have been significantly supported by the use of turbochargers with guide vane-controlled turbines. In this way, the possible operating range of the turbine can be significantly increased with good efficiency compared to bypass-controlled turbines.

When using a turbocharger with variable turbine geometry (VTG) it is known that the efficiency when using straight blades (i.e. blades with a straight skeleton or profile center line and a symmetrical thickness distribution) reaches its limits at high degrees of supercharging. This applies in particular to the start-up range of the engine (low engine speed at full load). However, the properties of the straight blades with regard to their controllability can be described as good.

In order to compensate for the mentioned thermodynamic deficits of the straight blades, the aforementioned suggests US 6,709,232 B1 the use of curved or profiled blades. In the closed state of these blades, that is, when the blades are very close to one another, this occurs in the case of the one known from the generic document Arrangement to incorrect flow, which lead to adjusting torques that act either in the direction of opening the blades or closing the blades. Furthermore, the speed distribution and the resulting distribution of the static pressure in the duct, which is formed by two adjacent blades, influence the generation of moments on the blades. Furthermore, this effect can lead to an increase in the hysteresis during the control process, which can even lead to a loss of the adjustability if the forces that occur exceed the forces of the adjusting device.

It is therefore the object of the present invention to provide a blade of the type specified in the preamble of claim 1 and a turbocharger of the type specified in the preamble of claim 7, which enables good thermodynamic properties of its blades of the adjustable turbine geometry with improved control properties.

This object is achieved by the features of claim 1 and claim 7, respectively.

By using a turbocharger with the blade shape according to the invention, in addition to improving the thermodynamics by reducing the total pressure losses in the diffuser, the closing torque that occurs can be significantly reduced. The control behavior can thus be improved while maintaining the axis of rotation of the blade.

If opening moments are to be achieved, the axis of rotation must be shifted towards the blade leading edge. For this purpose, the blade geometry according to the invention offers the advantage that the displacement of the axis of rotation only has to take place by a smaller amount compared to the blades known from the prior art. Thus, a smaller radial installation space is required compared to known solutions.

The subclaims contain advantageous developments of the invention.

The wave-shaped profile center line of the blade according to the invention consists of two counter-rotating corrugated bulges. If this profile centerline shape is entered in an XY coordinate system with a horizontal X axis and a vertical Y axis, negative Y values are initially obtained after the blade leading edge Passing through the X-axis change into positive Y-values and where the profile center line has a turning point.

With regard to the thermodynamic properties, the orientation of the blade leading edge is changed, which reduces the impact losses due to a flatter flow towards the blade leading edge.

Furthermore, lower speeds result in the channels between the blades, which results in lower flow losses, although an approximately constant deflection in the circumferential direction can be maintained.

Furthermore, the moments that occur are changed in the "opening" direction, which is achieved by lower speeds in the duct, the static pressure increasing and as a result, in connection with the pivot point, a moment in the "opening" direction. This applies to the front area of the blade underside and the rear area of the blade top. If the rear area 13 'of the blade top is designed in a straight line, the effective channel cross-section is enlarged.

This in turn results in lower losses due to low speeds in the channel with constant deflection in the circumferential direction.

In this embodiment, too, there is a change in the moments occurring in the "opening" direction due to lower speeds in the channel, which in turn increases the static pressure which, in conjunction with the pivot point, creates a moment in the "opening" direction.

Fig. 1

eine teilweise aufgebrochene perspektivische Darstellung eines erfindungsgemäßen Turboladers;

Fig. 2

eine vereinfachte Darstellung einer ersten Ausführungsform einer erfindungsgemäßen Schaufel der verstellbaren Turbinengeometrie des Turboladers gemäß Fig. 1;

Fig. 3

ein X-Y-Koordinatensystem, in dem der Verlauf der Profilmittellinie bzw. Skelettlinie der Schaufel gemäß Fig. 2 dargestellt ist;

Fig. 4 und 5

weitere Ausführungsvarianten der Schaufel gemäß Fig. 2;

Further details, advantages and features of the present invention emerge from the following description of exemplary embodiments with reference to the drawing. It shows:

Fig. 1

a partially broken perspective view of a turbocharger according to the invention;

Fig. 2

a simplified representation of a first embodiment of a blade according to the invention according to the adjustable turbine geometry of the turbocharger Fig. 1 ;

Fig. 3

an XY coordinate system in which the course of the profile center line or skeleton line of the blade according to Fig. 2 is shown;

Figures 4 and 5

further design variants of the blade according to Fig. 2 ;

In Fig. 1 an inventive turbocharger 1 is shown in the form of a VTG exhaust gas turbocharger.

The turbocharger 1 has a turbine housing 2 which comprises an exhaust gas inlet opening 3 and an exhaust gas outlet opening 4.

Furthermore, a turbine wheel 5, which is fastened on a shaft 6, is arranged in the turbine housing 2.

A plurality of blades, one of which is in Fig. 1 only the blade 7 can be seen is arranged in the turbine housing 2 between the exhaust gas inlet opening 3 and the turbine wheel 5.

Of course, the turbocharger 1 according to the invention also has all other conventional components of a turbocharger such as a compressor wheel, which is fastened on the shaft 6 and arranged in a compressor housing, as well as the entire bearing unit, which, however, are not described below as they are used for the explanation of Principles of the present invention are not required.

In Fig. 2 a first embodiment of a blade 7 according to the invention is shown.

The blade 7 has a blade underside 8 which, in the installed state, is the blade side facing the turbine wheel 5.

The blade 7 also has a blade upper side 9 which, together with the blade lower side 8, determines the thickness of the blade 7.

The blade bottom 8 and the blade top 9 run at the in Fig. 2 shown position of the blade 7 on the right side in a blade leading edge 10 and on the left side in a blade trailing edge 11 together.

The blade lower and upper side 8 and 9 respectively define a profile center line 12 lying between them, which is also referred to as the skeleton line. How Fig. 2 In the illustrated embodiment, this profile center line 12 has two oppositely curved areas 12A and 12B, the configuration of which results in a wave-shaped contour of the profile center line 12, the areas 12A and 12B each being designed in the manner of corrugated flares. Fig. 2 also makes it clear that the profile center line 12 has a turning point WP and also makes it clear Fig. 2 the position of the angle of incidence y on the blade leading edge 10, which is also referred to as the nose of the profile of the blade 7. The angle of attack y is the acute angle of the tangent of the profile center line 12 at the turning point and the tangent of the profile center line 12B at the blade leading edge 10.

In Fig. 3 the course of the profile center line 12 is plotted in an XY coordinate system, the X axis representing the blade length of the blade 7.

The graph of the profile center line 12 shows the region 12B beginning at the blade leading edge 10 which has negative Y values between the blade leading edge 10 (X = 0, Y = 0) and the zero crossing (X≈0.27; Y = 0). The zero crossing is preferably in a range between X = 0.10 and X = 0.40.

The second region 12A always has positive values from the mentioned zero crossing up to the blade trailing edge 11 (X = 1, Y = 0). The turning point WP is at a value of approximately X = 0.4; Y = 0.02).

At the in Fig. 3 The selected representation is a course of the profile center line or skeleton line 12, formed as a perpendicular distance relative to the chord, which is defined by linear Connection of the blade leading edge and the blade trailing edge is formed and represents the length of the blade.

The Figures 4 and 5 represent two basically conceivable design variants of the blade 7 according to FIG Fig. 2 represents. In the embodiment according to Fig. 4 the upper side 9 in the area 13 adjoining the blade trailing edge 11 is curved. This area is in Fig. 5 marked with the reference numeral 13 'and is flattened, that is, not curved, but flat.

To reveal the features of the present invention, in addition to the written description, explicit reference is made to the drawing.

List of reference symbols

1

turbocharger

2

Turbine housing

3

Exhaust gas inlet opening

4th

Exhaust gas outlet

5

Turbine wheel

6th

wave

7, 7 '

Shovels

8, 8 '

Blade underside (lower guide surfaces)

9, 9 '

Vane top (upper guide surfaces)

10, 10 '

Blade leading edge

11, 11 '

Blade trailing edge

12, 12 '

Profile center line (skeleton line)

12A, 12B

Bulbous areas of the profile center line 12

13, 13 '

Rear areas of the profile top 9 or 9 '

WP

Turning point

y

Angle of attack

Claims (7)

1. Vane (7; 7') of a turbocharger (1) with variable turbine geometry, which turbocharger has a turbine housing (2) with an exhaust-gas inlet opening (3) and with an exhaust-gas outlet opening (4), in which turbine housing there is arranged a turbine wheel (5) fastened on a shaft (6), wherein the vane (7) comprises the following:

   • a vane bottom side (8; 8') and a vane top side (9; 9'), which define the vane thickness,

   • a vane leading edge (10; 10') at a first intersection of the vane bottom side (8; 8') and the vane top side (9; 9'),

   • a vane trailing edge (11; 11') at a second intersection of the vane bottom side (8; 8') and the vane top side (9; 9'), and

   • a profile centreline (12) which is defined by the vane bottom side (8; 8') and the vane top side (9; 9') and which runs between these from the vane leading edge (10; 10') to the vane trailing edge (11; 11'),

   • wherein the course of the profile centreline (12) is undulating with two opposing antinodes (12A, 12B), wherein the profile centreline (12) has an inflection point (WP); and

   • wherein an angle of incidence γ preferably lies in a range from 10° to 30°, wherein the angle of incidence γ is the acute angle of a tangent to the profile centreline (12) at the inflection point (WP) and of a tangent to the profile centreline (12) at the vane leading edge (10; 10');

   characterized in that, if the profile centreline (12; 12') is plotted on an X-Y coordinate system whose X-axis constitutes the vane length of the vane (7; 7') and the vane leading edge (10; 10') and the vane trailing edge (11; 11') are situated at Y=0, one of the antinodes of the profile centreline (12) is a region (12B) which begins at the vane leading edge (10, 10') and which has negative Y values between the vane leading edge (10) and a zero crossing of the profile centreline (12) through the X-axis, and in that the second of the antinodes of the profile centreline (12) is a region (12A) which always has positive Y values proceeding from the zero crossing of the profile centreline (12) through the X-axis to the vane trailing edge (11), wherein the zero crossing is situated in a region between x=0.27 and x=0.40, wherein the vane leading edge (10; 10') is situated at x=0 and the vane trailing edge (11; 11') is situated at x=1.
2. Vane according to Claim 1, characterized in that the vane (7) has a trailing region (13) of the vane top side (9), which trailing region (13) is curved.
3. Vane according to Claim 1, characterized in that the vane (7') has a trailing region (13') of the vane top side (9'), which trailing region (13') is of flat form.
4. Vane according to any one of the preceding claims, characterized in that the vane top side (9; 9') has both concave and convex portions.
5. Vane according to Claim 4, characterized in that the vane top side (9; 9') has, in a leading region, a concave portion which transitions, in the direction of the vane trailing edge (11; 11'), into a convex portion.
6. Vane according to Claim 1, wherein the inflection point (WP) is situated at approximately x=0.4.
7. Turbocharger (1) having a turbine housing (2) which has an exhaust-gas inlet opening (3) and an exhaust-gas outlet opening (4);
   having a turbine wheel (5) which is fastened on a shaft (6) and which is arranged in the turbine housing (2);
   having a plurality of vanes (7; 7') which are arranged in the turbine housing (2) between the exhaust-gas inlet opening (3) and the turbine wheel (5), characterized in that the vanes (7; 7') are designed according to any one of Claims 1 to 6.

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