DE102008000724B4 - Exhaust gas turbocharger with adjustable turbine geometry - Google Patents

Abstract

Exhaust gas turbocharger for an internal combustion engine with adjustable guide vanes (13), the guide vanes (13) being coupled to one another and rotatably mounted in a first carrier ring (17) of the exhaust gas turbocharger, characterized in that at least when the guide vanes (13) are fully open, the lugs (21) of the guide vanes protrude in the radial direction beyond the outer diameter (Da) of the first carrier ring (17).

Description

State of the art

Exhaust gas turbochargers with adjustable turbine geometry are known from the prior art for diesel internal combustion engines and Otto engines. The adjustable turbine geometry makes it possible to adjust the flow cross-section of the turbine depending on engine operation, thereby improving the efficiency of the turbocharger and consequently also of the internal combustion engine.

For this purpose rotatably mounted guide vanes are provided between the volute housing and the turbine wheel. At low engine speeds, the flow cross section of the turbine is reduced by closing the guide vanes. Due to the resulting increase in pressure drop or the increasing kinetic energy, the boost pressure increases and, as a result, the torque of the internal combustion engine.

At high engine speeds, the apparatus is opened so that the desired boost pressure is achieved at a low turbine pressure ratio, thereby reducing the fuel consumption of the internal combustion engine.

In the exhaust gas turbochargers known from the prior art, the guide vanes are coupled to an adjustment ring, which in turn is controlled by the control unit of the internal combustion engine via a pneumatically or electrically actuated actuator.

From the EP 0 160 460 A2 such an exhaust gas turbocharger with adjustable turbine geometry is known. In this exhaust gas turbocharger, the guide vanes are rotatably mounted with their bearing bolts in a carrier ring, the carrier ring being designed as a separate component and being inserted into the turbine housing of the exhaust gas turbocharger. The carrier ring forms channels with the vanes through which the hot exhaust gases flow before they hit the turbine wheel U.S. 2004/0081567 A1 discloses an exhaust gas turbocharger for an internal combustion engine with adjustable guide vanes, which are rotatably mounted in a first carrier ring of the exhaust gas turbocharger and are coupled to one another via an adjusting ring.

Because of the extremely high thermal stress on the carrier ring, particularly in the area of the bearing of the vanes, it is necessary to make this carrier ring from a heat-resistant and expensive material, which is also relatively difficult to machine. As a result, the material and machining costs of this carrier ring are relatively high.

Disclosure of Invention

The invention is based on the object of providing an exhaust gas turbocharger with adjustable turbine geometry, the production costs of which are lower than conventional exhaust gas turbochargers and which also has advantages over the prior art in terms of installation space requirement and weight.

This object is achieved according to the invention in an exhaust gas turbocharger for an internal combustion engine with adjustable guide vanes, the guide vanes being coupled to one another and rotatably mounted in a first carrier ring of the exhaust gas turbocharger, in that at least when the guide vanes are fully open, the noses of the guide vanes extend in the radial direction over the outer diameter of the protrude first carrier ring.

This measure reduces the outer diameter of the first carrier ring, which naturally results in a lower weight and a lower material requirement. In the same way, it is also possible to increase the inside diameter of the carrier ring so much that at least when the guide vanes are fully open, the ends of the guide vanes protrude in the radial direction inwards beyond the inner diameter of the first carrier ring.

Each of the measures mentioned, alone or particularly preferably in combination with one another, leads to a considerable reduction in the material to be used for the first carrier ring and consequently to weight and cost savings and also to a reduction in manufacturing costs due to the smaller areas to be machined.

The mountability of the exhaust-gas turbocharger according to the invention with adjustable turbine geometry is nevertheless ensured if the diffuser with closed guide vanes is inserted into the housing of the exhaust-gas turbocharger.

Since the first carrier ring according to the invention has only a small surface, the heat transfer from the first carrier ring to the rest of the exhaust gas turbocharger and into the engine compartment is reduced, which has a positive effect on the periphery of the exhaust gas turbocharger, in particular the internal combustion engine.

In a further advantageous embodiment of the invention, a second carrier ring is provided on the end faces of the guide vanes facing away from the first carrier ring. The second support ring serves to close off the channels formed by the first support ring and the vanes and is therefore exposed to the same thermal stresses as the first support ring and vanes. For this reason, it is preferably also made from a highly heat-resistant material and is therefore also very expensive to manufacture.

In order to reduce the material requirements for the second carrier ring, it is further provided that, at least when the guide vanes are fully open, the noses of the guide vanes protrude in the radial direction beyond the outer diameter of the second carrier ring and/or the ends of the guide vanes protrude in the radial direction beyond the inner diameter of the second carrier ring protrude. This also achieves the advantage according to the invention, namely a lower material requirement and lower production costs. It is obvious that it is also possible to design only the second carrier ring according to the invention with regard to its outer diameter and its inner diameter, if in rare cases it should be indispensable that the first carrier ring has to be dimensioned with regard to outer diameter and/or inner diameter in such a way that even when the guide vanes are fully open, they do not protrude beyond the first carrier ring in the radial direction. In short: the dimensioning according to the invention of the second support ring with regard to the outside diameter and inside diameter in relation to the guide vanes can be carried out independently of the design of the first support ring.

In order to improve the mounting of the guide vanes, a further embodiment of the invention provides for the guide vanes to be rotatably mounted in the second support ring on their end faces facing away from the adjustment ring.

It has proven to be advantageous if the guide vanes above an opening of 60%, preferably above 70°, particularly preferably above 80% and very particularly preferably above 90%, the lugs of the guide vanes in the radial direction over the outer diameter of the first Protrude carrier ring and / or the second carrier ring. The same also applies to the ends of the guide vanes and in relation to the inside diameter of the first carrier ring and/or the second carrier ring.

To ensure that the guide vanes can rotate freely between the first and second carrier rings and that there is no unnecessarily large gap between the end faces of the guide vanes and the carrier rings, spacers are provided between the first and second carrier rings.

These spacers serve as spacers between the first and second carrier rings. The choice of material from which these spacers are made ensures that the gap between the vanes and the support rings is always within tight limits at all operating temperatures. For example, it is possible to make the spacers and vanes from the same material.

It is of course possible to attach the spacers to the first carrier ring and/or the second carrier ring in a detachable or non-detachable manner. For example, the spacers can be screwed to the two carrier rings. It is also possible for the spacers to be in the form of tubular sleeves and for a screw to run inside these sleeves, which clamps the first carrier ring and the second carrier ring together. Alternatively, the spacers can also be designed as a stepped screw, which on the one hand assumes the connection function and on the other hand also the function of a spacer. Alternatively, the spacers can also be in the form of pins and can be connected to the carrier rings, for example by welding.

Further advantages and advantageous configurations of the invention can be found in the following drawing, its description and the patent claims. All of the features described in the drawing, its description and the patent claims can be essential to the invention both individually and in any combination with one another.

• 1 eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemäßen Abgasturboladers mit geöffneten Leitschaufeln,
• 2 eine schematische Darstellung eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Abgasturboladers mit geschlossenen Leitschaufeln, 3 Ansicht vorn vorne auf einen erfindungsgemäßen ersten Trägerring und
• 4A und 4B Ausführungsbeispiele von Distanzstücken.

Show it:

• 1 a schematic representation of a first exemplary embodiment of an exhaust gas turbocharger according to the invention with open guide vanes,
• 2 a schematic representation of a second embodiment of an exhaust gas turbocharger according to the invention with closed guide vanes, 3 Front view of a first carrier ring according to the invention and
• 4A and 4B Embodiments of spacers.

In 1 a housing of the exhaust gas turbocharger is provided with the reference number 1 . The housing 1 can be made in one piece or in several pieces (see the reference numerals 1a, 1b, 1c), depending on the requirements in the manufacture and assembly of the exhaust gas turbocharger.

As is well known, exhaust gas turbochargers have a turbine part that 1 is arranged on the right and a compressor part, which is in 1 is arranged on the left. In the turbine part is a turbi nenlaufrad 3 firmly connected to a shaft 5 and rotatably mounted in the housing 1 (storage not shown). A seal between shaft 5 and housing 1 bears the reference number 8.

At the left end of the shaft 5, a compressor impeller 7 is attached. The combustion air to be compressed flows to the compressor impeller 7 in the axial direction and leaves it in the radial direction. The direction of movement of the combustion air to be compressed is in 1 indicated by arrows 9. In the right-hand part of the housing 1 there is an inlet spiral 11 through which the exhaust gas emitted by the internal combustion engine (not shown) is fed to the turbine impeller 3 .

In a region between the inlet spiral 11 and the turbine impeller 3, a plurality of vanes 13 are distributed over the circumference of the exhaust gas turbocharger, of which in 1 only one is visible. The guide vanes 13 each have a bearing pin 15 on their end faces facing the first support ring 17 . The bearing bolts 15 and with it the associated guide vanes 13 are rotatably mounted in bearing bores (without reference numbers) in the first carrier ring 17 .

The rotary movement of the vanes 13 around the longitudinal axis of the bearing bolts 15 is in 1 indicated by a curved double arrow. Not shown in 1 the adjustment mechanism for the guide vanes 13 on the left of the first carrier ring 17.

The first carrier ring 17 and, if present, a second carrier ring 19 and the vanes 13 form flow channels for the hot exhaust gas, which flows from the inlet spiral 11 in the direction of the turbine impeller 3 . Because of the very high temperature load, the first carrier ring 17 and, if present, the second carrier ring 19 (see Fig 2 ) are made of a heat-resistant material.

The noses 21 of the guide vanes 13 are located in the vicinity of the inlet spiral 11, while the ends 23 of the guide vanes 13 are located in the vicinity of the turbine wheel 3. In 1 the guide vanes 13 are shown open and in this position protrude with their lugs 21 beyond an outer diameter D _a of the first support ring 17 . In this position, the guide vanes 13 protrude with their ends 23 inwards beyond an inner diameter D _i of the first support ring 17 .

The first carrier ring 17 and the second carrier ring 19 are advantageously spaced apart by spacers 33 . These spacers 33 can be designed, for example, as sleeves with a screw running inside, as a screw with stepped diameters, as pins or by a combination thereof (see FIG 4A and 4B) . A suitable bolt circle diameter for the arrangement of three, four or more spacers 33, which are distributed evenly or unevenly over the circumference 1 indicated by a dash-dotted line 25.

The diffuser, comprising the first carrier ring 17, the second carrier ring 19, the guide vanes 13 and the spacers (without reference numerals) are held by a spring element 27 in contact with the housing part 1c. At the same time, this spring element 27 can also assume the function of a heat shield and/or a seal.

In 2 a further exemplary embodiment of an exhaust gas turbocharger according to the invention is shown. The essential difference between the two exemplary embodiments is that the guide vanes 13 are mounted not only in the first carrier ring 17 but also in the second carrier ring 19 with the section 15a of the bearing pin.

At the in 2 In the exemplary embodiments shown, the guide vanes 13 are shown closed, so that the lugs 21 of the guide vanes 13 do not protrude beyond the outer diameter D _a of the first carrier ring 17 and also beyond the outer diameter of the second carrier ring 19 . Correspondingly, the ends 23 of the guide vanes 13 also do not protrude inwards beyond the inner diameter D _i of the first carrier ring 17 and the inner diameter of the second carrier ring 19 . This situation is explained below with reference to 3 explained in more detail.

3 shows a plan view of a first support ring 17 according to the invention with fully open guide vanes 13. With a dashed line is the right part 3 a guide vane 13 shown in the closed state. When the guide vanes 13 are open, the lugs 21 of the guide vanes 13 protrude in the radial direction beyond the outer diameter D _a of the first carrier ring 17 .

At the in 3 In the exemplary embodiment shown, when the guide vanes 13 are open, the ends 23 of the guide vanes 13 also protrude in the radial direction inwards beyond the inner diameter D _i of the first support ring 17 . How from the 3 is immediately clear, the first support ring 17 has only a small mass. As a result, the weight, material requirements and processing costs of this first carrier ring 17 according to the invention are very low. The same applies to the second support ring 19, which ultimately has a geometry similar to that of the first support ring 17, so that a separate graphic representation is dispensed with.

In summary, it can be stated that the geometry of the first carrier ring 17 and/or the second carrier ring 19 claimed according to the invention results in a considerable saving in material and processing costs, which has a favorable effect on the overall costs of the exhaust gas turbocharger, primarily because of the high material prices. Another advantage of these narrow carrier rings 17 and 19 is that the heat transfer from the carrier rings 17 and 19, which are exposed to extremely high temperatures during operation, is reduced to the housing 1 of the exhaust gas turbocharger according to the invention.

4 shows exemplary embodiments of spacers according to the invention.

At the in 4a In the first exemplary embodiment shown, the spacer consists of a pin or a stepped screw that performs the functions of “connecting” and “ensuring the axial gap”.

In the second embodiment according to 4b the spacer 33 is designed in two parts and comprises a sleeve 29 and a through-bolt 31. The sleeve 29 assumes the “spacing” function, while the through-bolt 31 assumes the “connecting” function of the first carrier ring 17 and the second carrier ring 19. Of course, many other embodiments of the spacers 33 are possible.

Claims (12)

Exhaust gas turbocharger for an internal combustion engine with adjustable guide vanes (13), the guide vanes (13) being coupled to one another and rotatably mounted in a first support ring (17) of the exhaust gas turbocharger, characterized in that at least when the guide vanes (13) are fully open, the lugs (21) of the guide vanes protrude in the radial direction beyond the outer diameter (D _a ) of the first carrier ring (17). Exhaust gas turbocharger for an internal combustion engine with adjustable guide vanes (13), the guide vanes (13) being rotatably mounted in a first support ring (17) of the exhaust gas turbocharger and being coupled to one another via an adjusting ring (27), the ends at least when the guide vanes (13) are fully open (23) of the guide vanes protrude in the radial direction beyond the inner diameter (D _i ) of the first carrier ring (17), characterized in that - a second carrier ring (19) is provided on the end faces of the guide vanes (13) facing the first carrier ring (17). - that at least when the guide vanes (13) are fully open, the lugs (21) of the guide vanes protrude in the radial direction beyond the outer diameter (D _a2 ) of the second carrier ring (19), and/or that when the guide vanes (13) are open, they are larger 60% the noses (21) of the vanes (13) in the radial direction over the outer diameter (D _a , D _a2 ) of the first carrier ring (17) and/or the second carrier ring (19) protrude. exhaust gas turbocharger claim 1 , characterized in that a second carrier ring (19) is provided on the end faces of the guide vanes (13) applied to the first carrier ring (17). exhaust gas turbocharger claim 2 or 3 , characterized in that the guide vanes (13) are mounted in the second carrier ring (19). Exhaust gas turbocharger according to one of claims 3 or 4 , characterized in that the guide vanes (13) are mounted in the second carrier ring (19) on their end faces facing away from the first carrier ring (17). exhaust gas turbocharger claim 1 , characterized in that, at least when the guide vanes (13) are fully open, the lugs (21) of the guide vanes protrude in the radial direction beyond the outer diameter (D _a2 ) of a second carrier ring (19). Exhaust gas turbocharger according to one of claims 2 until 6 , characterized in that, at least when the guide vanes (13) are fully open, the ends (23) of the guide vanes protrude in the radial direction beyond the inside diameter (D _i2 ) of the second carrier ring (19). exhaust gas turbocharger claim 1 , characterized in that with an opening of the guide vanes (13) greater than 60%, preferably greater than 70%, particularly preferably greater than 80% and very particularly preferably greater than 90%, the lugs (21) of the guide vanes (13) in the radial direction over the Outer diameter (D _a , D _a2 ) of the first support ring (17) and / or a second support ring (19) protrude. Exhaust gas turbocharger according to one of claims 2 until 8th , characterized in that with an opening of the guide vanes (13) greater than 60%, preferably greater than 70%, particularly preferably greater than 80% and very particularly preferably greater than 90%, the ends (23) of the guide vanes (13) in the radial direction over the Protrude inner diameter (D _i , D _i2 ) of the first support ring (17) and / or the second support ring (19). Exhaust gas turbocharger according to one of Claims 4 until 9 , characterized in that spacers (33, 31, 29) are provided between the first support ring (17) and the second support ring (19). exhaust gas turbocharger claim 10 , characterized in that the spacers (33, 31, 29) are detachably or non-detachably attached to the first carrier ring (17) and/or the second carrier ring (19). Exhaust gas turbocharger according to one of claims 2 until 11 , characterized in that the guide vanes, the first support ring (17) and/or the second support ring (19) are made of heat-resistant materials, in particular high-nickel and/or high-chromium nickel-based alloys, in particular HK30 = 1.4841, 1.4848 and/or or high-temperature steels.

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