EXHAUST GAS TURBOCHARGER FOR HIGH-PERFORMANCE ENGINE CONCEPTS

Abstract

An exhaust gas turbocharger assembly for a turbocharged internal combustion engine with a spiral housing, having at least two separated flow passages, at least one separating tongue separating the adjacent flow passages, and a turbine rotor, wherein the separating tongue is arranged such that the end of the separating tongue, said end facing the turbine rotor, is spaced from the edge of the turbine rotor such that crosstalk between the flow passages in the flow direction occurs upstream of the turbine rotor, wherein a crosstalk cross section A.sub.ÜS is determinable depending on the distance between the separating tongue end and the edge of the turbine rotor.

Claims

1. An exhaust gas turbocharger assembly for a turbocharged internal combustion engine, the assembly comprising: a spiral housing having at least two separated flow passages, the at least two separated flow passages having a portion thereof adjacent to one another; at least one separating tongue separating the at least two separated flow passages; and a turbine rotor, wherein the separating tongue is arranged such that an end of the separating tongue facing the turbine rotor is spaced from the edge of the turbine rotor such that crosstalk between the flow passages in a flow direction occurs upstream of the turbine rotor, wherein a crosstalk cross section is determinable depending on a distance between the separating tongue end and an edge of the turbine rotor, wherein the exhaust gas turbocharger assembly has a relative crosstalk cross section A.sub.REL=A.sub.ÜS A.sub.TR greater than or equal to 0.06 or greater than or equal to 0.1, if the turbine rotor has a fixed turbine geometry, and/or wherein the exhaust gas turbocharger assembly has a relative crosstalk cross section A.sub.REL=A.sub.ÜS A.sub.TR greater than or equal to 0.1, if the turbine rotor has a variable turbine geometry, where A.sub.TR indicates the outlet cross section at the turbine rotor.

2. The exhaust gas turbocharger assembly according to claim 1, wherein the crosstalk cross section A.sub.ÜS results from the addition of an outer crosstalk cross section A.sub.ÜS_outer and an inner crosstalk cross section A.sub.ÜS_inner, wherein the outer crosstalk cross section A.sub.ÜS_outer is determined as a function of the distance between the separating tongue end and the edge of the cartridge with a variable turbine geometry and the inner crosstalk cross section A.sub.ÜS_inner is determined as a function of the tangential annular gap within the cartridge with a variable turbine geometry.

3. The exhaust gas turbocharger assembly according to claim 1, wherein the exhaust gas turbocharger assembly has a relative crosstalk cross section A.sub.REL=A.sub.ÜS/A.sub.TR in a range greater than or equal to 0.20, greater than or equal to 0.30, or greater than or equal to 0.40.

4. The exhaust gas turbocharger assembly according to claim 1, wherein the exhaust gas turbocharger assembly has a relative outer crosstalk cross section A.sub.REL_outer greater than or equal to 0.10, greater than or equal to 0.20, or greater than or equal to 0.40, determined as the quotient of the outer crosstalk cross section A.sub.ÜS_outer and the outlet cross section at the turbine rotor A.sub.TR.

5. The exhaust gas turbocharger assembly according to claim 1, wherein the exhaust gas turbocharger assembly has a relative inner crosstalk cross section A.sub.REL_inner greater than or equal to 0.025, or approximately 0.03 determined as the quotient of the inner crosstalk cross section A.sub.ÜS_inner and the outlet cross section at the turbine rotor A.sub.TR.

6. The exhaust gas turbocharger assembly according to claim 1, wherein a rotation angle of the flow passage segments about the turbine axis is 180°+/−45°, 180°+/−20°, or 180°+/−5°.

7. An internal combustion engine with exhaust gas turbocharging comprising an exhaust gas turbocharger assembly according to claim 1.

8. The internal combustion engine according to claim 7, comprising an exhaust manifold routing which is separated according to the ignition sequence and opens into the exhaust gas turbocharger assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0054] FIG. 1 shows, in a highly schematic illustration, a cross-sectional view of an exemplary dual-volute exhaust gas turbocharger assembly according to the present invention; and

[0055] FIG. 2 shows, in a highly schematic illustration, a cross-sectional view of an exhaust gas turbocharger assembly according to the present invention.

DETAILED DESCRIPTION

[0056] FIG. 1 schematically shows the basic structure of an exhaust gas turbocharger assembly 1 cut perpendicular to the axis of rotation 11 of rotor 6. The illustrated turbocharger assembly 1 is an example for a dual-flow passage turbocharger assembly 1, i.e., for a turbocharger assembly 1 with two flow passages 3, 4. Turbocharger assembly 1 has a turbine housing 2 in which a rotor 6 is mounted on a rotatable shaft 11. Turbocharger assembly 1 is characterized in that the two flow passages 3, 4 are arranged one above the other and surround rotor 6 in a spiral shape at least along an arcuate section on radii of different sizes. In other words, housing 2 is designed like a spiral, wherein flow passages 3, 4 are separated by a radial housing wall as a separating tongue 5 and wherein turbine rotor 6 is arranged approximately in the center of the housing (so-called dual-volute concept). The two inlet openings of dual-volute turbine 1 are disposed in a flange of housing 2 radially at different distances from shaft 11 of turbine rotor 6, wherein a flow passage 3, 4 of turbocharger assembly 1 adjoins each inlet opening and the two flow passages 3, 4 are separated from one another by means of a separating tongue 5 up to the vicinity of rotor 6. In this way, the exhaust gas flows of the two flow passages 3, 4 are conducted separately from one another in the direction of rotor 6.

[0057] According to the invention, it is provided that separating tongue 5 does not come as close as possible to edge 8 of turbine rotor 6. Rather, according to the invention, a distance between separating tongue end 7 and the edge of turbine rotor 8 is provided, which is marked as d.sub.TT in the figures. Depending on the distance d.sub.TT between separating tongue end 7 and the edge of turbine rotor 8, a crosstalk cross section A.sub.ÜS can be determined, which can be obtained or estimated as area data, for example, by multiplying the distance d.sub.TT by the flow passage height multiplied by the number of separator tongues (usually 2).

[0058] According to the invention, it is provided for the ratio of the crosstalk cross section A.sub.ÜS to the outlet cross section of turbine rotor 6 that exhaust gas turbocharger assembly 1 has such a relative crosstalk cross section A.sub.REL=A.sub.ÜS/A.sub.TR greater than or equal to 0.06, where A.sub.TR indicates the outlet cross section at turbine rotor 6. In other words, the area upstream of the turbine that allows crosstalk of the exhaust gas flows with respect to the flow passage separation is at least 6% of the outlet area of the turbine rotor. However, it is preferably greater, for example, greater than 10% of the outlet area, preferably greater than or equal to 20%, and particularly preferably it is 30% or more in relation to the outlet area. As a result, certain advantages are achieved, especially for the range of the rated power and the high speeds of the internal combustion engine, advantages that could not be achieved in particular in combination with previous designs. In addition to a maximum path of the exhaust gas in the turbine, wherein a good turbine efficiency can be ensured at the same time, the same exhaust gas back pressure level of the individual flow passages can also be achieved. With a rotation angle of the flow passage segments about turbine axis 11 of 180°+/−45°, preferably 180°+/−20°, particularly preferably 180°+/−5°, the avoidance of the exhaust gas crosstalk between the cylinders of the internal combustion engine is thus primarily achieved by maximizing the run lengths.

[0059] FIG. 2 schematically shows the basic structure of a further embodiment of exhaust gas turbocharger assembly 1 cut perpendicular to the axis of rotation 11 of rotor 6. The illustrated turbocharger assembly 1 is again an example of a dual-flow passage turbocharger assembly 1, i.e., for a turbocharger assembly 1 with two flow passages 3, 4. The same reference symbols as in FIG. 1 designate the same functional components. In contrast to the embodiment in FIG. 1, turbocharger assembly 1 does not have a simple turbine rotor 6, but a cartridge with a variable turbine geometry 9 is disposed in its place. The cartridge with a variable turbine geometry 9 has in its center a turbine rotor 6 which is movably mounted on a shaft 11. There is a blade bearing ring or a carrier ring with adjustable blades around turbine rotor 6 and spaced from it by an annular gap 10.

[0060] In an advantageous embodiment of the invention, the crosstalk cross section A.sub.ÜS results from the addition of an outer crosstalk cross section A.sub.ÜS_outer and an inner crosstalk cross section A.sub.ÜS_inner, wherein the outer crosstalk cross section A.sub.ÜS_outer can be determined as a function of the distance d.sub.TT between the separating tongue end and edge 8 of the cartridge with a variable turbine geometry 9 and the inner crosstalk cross section A.sub.ÜS_inner can be determined as a function of the tangential annular gap 10 within the cartridge with a variable turbine geometry 9. Turbocharger assembly 1 in FIG. 2 has a relative crosstalk cross section greater than or equal to 10%.

[0061] In other words, when a cartridge 9 is used, a maximization of the crosstalk cross section can be achieved by increasing the distance d.sub.TT between the separating tongue and VTG blade inlet 8, which is described hereafter by the term outer crosstalk cross section, and by increasing the distance between the VTG blade outlet and the turbine rotor (tangential annular gap 10 within cartridge 9), which is described hereafter by the term inner crosstalk cross section, or by a combination of both increases.

[0062] In every case, the flow passage separation should be eliminated before the entry into VTG cartridge 9. Thus, the entire VTG cartridge 9 and the entire rotor circumference are available for the through-flow for each exhaust gas pulse. As a result, it is possible to reduce the damming behavior and at the same time to improve the residual gas flushing, especially at the rated power. Maximizing the crosstalk cross section leads to a reduction in the time-averaged exhaust gas back pressure upstream of VTG cartridge 9. The concept is therefore primarily suitable for optimizing the rated power range.

[0063] In a further embodiment of this exhaust gas turbocharger assembly 1 of the invention with a variable turbine geometry, exhaust gas turbocharger assembly 1 has a relative outer crosstalk cross section A.sub.REL_outer greater than or equal to 0.10, preferably greater than or equal to 0.20, more preferably greater than or equal to 0.40, determined as the quotient of the outer crosstalk cross section A.sub.ÜS_outer and the outlet cross section at the turbine rotor A.sub.TR.

[0064] In an embodiment of an exhaust gas turbocharger assembly 1 with a variable turbine geometry, it has a relative inner crosstalk cross section A.sub.REL_inner greater than or equal to 0.025, preferably approximately 0.03, determined as the quotient of the inner crosstalk cross section A.sub.ÜS_inner and the outlet cross section at the turbine rotor A.sub.TR.

[0065] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims