DE102014226341A1 - Compressor, exhaust gas turbocharger and internal combustion engine - Google Patents

Abstract

A compressor (14) having a compressor housing (38) and a compressor impeller (36) rotatably mounted within a flow space of the compressor housing (38) dividing the flow space into a low pressure space (44) and a high pressure space (48), the compressor housing (38 ) a the compressor impeller (36) between the inlet edges (56) and its outlet edges (58) radially surrounding, of this via an impeller gap (64) spaced first housing wall (60) and one of the first housing wall (60) with respect to the axial direction of the compressor impeller ( 36) opposite the second housing wall (78) is formed, and wherein the first housing wall (60) in one of the transition from the impeller gap (64) to the high-pressure chamber (48) outgoing inlet portion (80) of the high-pressure chamber (48) so far in the direction the second housing wall (78) extends so that the first housing wall (60) partially covers the exit edges (58) of the compressor wheel (36) characterized in that the first housing wall (60) within the inlet section (80) has a first partial section (4) adjoining the transition and a second partial section (86), wherein the ratio of housing wall approach (x, y) to partial section length in the first section (84) is greater than in the second section (86).

Description

The invention relates to a compressor, an exhaust gas turbocharger with such a compressor and an internal combustion engine, in particular for use in a motor vehicle.

The use of one or more turbochargers to increase the specific power and to reduce the specific fuel consumption of internal combustion engines is known.

Exhaust gas turbochargers have an integrated into an exhaust line of the internal combustion engine turbine with a turbine impeller which is rotatably mounted within a turbine housing, and integrated into the fresh gas line of the internal combustion engine compressor with a compressor impeller which is rotatably mounted within a compressor housing on. The turbine wheel and the compressor wheel are rotatably connected via a shaft. During operation of the internal combustion engine, the turbine impeller is impinged by the exhaust gas flow and thereby driven in rotation, wherein this rotation is transmitted via the shaft to the compressor impeller. The thus caused rotation of the compressor wheel generates the desired compression of the fresh gas.

The impellers of the turbine and the compressor are each disposed within a flow space formed by the associated housing, whereby it is divided into a low-pressure space and a high-pressure space located downstream of the compressor impeller. The low-pressure space is located downstream of a turbine and upstream of the impeller in a compressor. By contrast, the high-pressure chamber is located upstream of a turbine and downstream of the respective impeller in the case of a compressor. In order to minimize the flow around the impeller and, in the case of a compressor, a backflow of already compressed gas from the high-pressure space into the low-pressure space, the impeller gap which is formed between the respective impeller and the housing wall surrounding it radially should be as small as possible.

Compressors of exhaust gas turbochargers for automotive applications are usually carried out in a radial design, since in this way high pressure ratios (π _{V, tt} > 3) can already be achieved by means of a single compressor stage. Another advantage of centrifugal compressors compared to compressors of axial design is the relatively low space requirement.

A centrifugal compressor sucks the gas to be compressed in the axial direction (relative to the rotational axis of the compressor impeller). By impulse transmission from the rotating impeller blades, the gas in the blade passages of the compressor impeller is accelerated. As a result of the divergent shape of the blade channels, the extraction of static pressure begins by the conversion of kinetic energy of the gas into potential energy even before the impeller outlet.

• – Reduktion der Meridiangeschwindigkeit und Aufbau statischen Drucks durch Aufweitung des wirksamen Strömungsquerschnitts;
• – Aufbau statischen Drucks durch Reduktion der Umfangsgeschwindigkeit infolge einer Zunahme des wirksamen Radius bei der Durchströmung des Diffusors (Drallerhaltung).

The compressor impeller is usually followed by a parallel-walled executed diffuser mostly radial design. The purpose of the diffuser is to convert a large part of the kinetic energy still remaining in the gas after the impeller outlet as efficiently as possible into pressure. This transformation is based on the following principles of action:

• - Reduction of the meridian speed and build-up of static pressure by widening the effective flow cross-section;
• - Construction of static pressure by reducing the peripheral speed due to an increase in the effective radius in the flow through the diffuser (swirl maintenance).

Vaneless diffusers of centrifugal compressors are usually designed as a parallel-walled, rotationally symmetrical (with respect to the rotational axis of the compressor impeller) flow space and ensure a wide and stable working range of the compressor. Especially at the diffuser inlet, however, inhomogeneous flow conditions prevail as a consequence of the non-uniform impeller outflow in the circumferential direction. In particular, near the housing wall ("shroud") which is distal with respect to the impeller hub, the impeller gap causes the formation of secondary flows in the compressor impeller (so-called blade tip vortex). This leads equally to a deteriorated flow just in the vicinity of the Shroud. Irrespective of the operating state, the gas flow on the diffuser inlet is less affected by the flow of gas from the shroud side than the stroke side (the region of the diffuser lying close to the hub-side housing wall). This causes, depending on the operating state of the centrifugal compressor, an increasing instability of the flow at the diffuser inlet and can lead to the stall and to the onset of gas flowing back into the compressor impeller.

By reducing the effective flow cross section at the diffuser inlet via a so-called "pinch", the flow field at the diffuser inlet can be effectively stabilized. In this case, a pinch is understood as a reduction in cross-section of the flow space formed by the diffuser, which results in the diffuser width at the diffuser inlet being greater than at the diffuser outlet. For this purpose, it can be provided that one or both of the housing walls protrude so far into the diffuser flow space that they partially cover the outlet edges of the compressor impeller. The positive effect of a simple (Shroud or Hub) or double (on both sides) Pinchs is based in particular on raising the speed level near the Shroud and improving the mass flow rate just in this area.

A radial compressor with a Shroud pinch is for example from the JP 3260399 A or the JP 2012-154204 A known.

From the DE-OS 1 628 227 In addition, a compressor with a blade-less diffuser is known, wherein in a portion of the diffuser a cross-sectional reduction of the free flow space is provided by an arcuate recess of one or both of the housing walls forming the diffuser.

The EP 0 402 870 A1 discloses a centrifugal compressor whose diffuser is formed with a double pinch. In addition, the housing wall on the shroud side of the diffuser at the diffuser exit forms a further cross-sectional reduction for the diffuser flow space. This reduction in cross-section is intended to function as an outlet throttle, thereby reducing the pressure loss as well as the risk of a stall and a backflow of the compressed gas. In the area between the Shroud pinch and the outlet throttle, the two housing walls of the diffuser are aligned in parallel.

And finally is out of the US 2004/0146396 A1 a radial compressor known, the diffuser is formed by two parallel housing walls. In the US 2004/0146396 A1 not described in the local 1 is shown that the housing wall is formed on the Shroud side at the diffuser inlet with an S-shaped curve, whereby this housing wall forms an overlap of the arranged between this housing wall and the corresponding side of the impeller impeller gap. Of the 1 can also be seen that the compressor impeller is formed closed on the Shroud side and thus forms internal flow channels. The problem of blade tip vortexes and unintentional backflow across the impeller gap on the Shroud side, as known from the almost exclusively used for car applications, on the Shroud side open compressor wheels, arises in the compressor impeller according to the US 2004/0146396 A1 not to the relevant extent.

Based on this prior art, the present invention seeks to provide a way to improve the efficiency and the map characteristic of a compressor.

This object is achieved by a compressor according to claim 1. An exhaust gas turbocharger comprising such a compressor is subject matter of claim 9. The subject of claim 10 is an internal combustion engine with a compressor according to the invention. Advantageous embodiments of the compressor according to the invention and thus also the exhaust gas turbocharger according to the invention and the internal combustion engine according to the invention are objects of the dependent claims and will become apparent from the following description of the invention.

The invention is based on the finding that by combining a Shroud pinch with a covering of the impeller gap formed between the compressor impeller and the housing on the Shroud side, a further improvement in the efficiency and characteristics of the compressor can be achieved. The peculiarity of the cover of the impeller gap is that despite a narrowing of the effective flow cross section caused by this at the diffuser inlet the map width of the compressor is substantially maintained and in particular no relevant shift the Stopfgrenze towards a higher mass flow is recorded. The achievable through the cover of the impeller gap fluidic advantages, in particular the reduction of a backflow of already compressed gas over the impeller gap, is therefore not compensated by actually expected flow disadvantages and thus comes substantially fully to effect.

According to this finding, a compressor with a (single or multi-part) compressor housing and a rotatably mounted within a flow chamber of the compressor housing (in particular on the Shroud side trained) compressor wheel claimed, the compressor impeller the flow space in a low-pressure chamber and a high-pressure chamber (the in particular acts as a diffuser), wherein the compressor housing a the compressor impeller between the (formed by blades) inlet edges and the outlet edges radially surrounding, spaced therefrom by a Laufradspalt first housing wall and one of the first housing wall with respect to the axial direction of the compressor impeller in the region of the high-pressure chamber opposite forming the second housing wall, and wherein the first housing wall in an outgoing from the transition from the impeller gap to the high-pressure chamber inlet portion so far in the direction of the second hous The second housing wall partially covers the exit edges of the compressor impeller (thereby forming a shroud pinch).

According to the invention, this compressor is characterized in that the first housing wall within the inlet section comprises a first section adjoining the junction and a second section (preferably adjoining the first section), the (positive) ratio of housing wall approach (ie the approximation of the housing wall approach first housing wall to the second housing wall in the corresponding subsection) to subsection length in the first subsection is greater than (in particular at least two, three or four times as large as) in the second subsection. In this case, the first subsection represents the cover for the impeller gap, which is relatively short in comparison to the second subsection, but projects relatively far (with respect to its subsection length) within this comparatively short first subsection into the flow space of the high pressure chamber. By contrast, the second subsection represents the Shroud pinch, which has a flow-bundling function and is therefore relatively long in comparison with the first subsection, but leads only to a relatively small housing wall approach (based on its subsection length) in the course of this second subsection. In this case, the (absolute) housing wall approach of the second subsection may be the same or, in particular, greater than that of the first subsection. Due to the relatively small increase in housing wall proximity through the second section, excessive deflection and constriction of the gas flowing through the high-pressure chamber is avoided. The relative lengths are based on the lengths along the high pressure chamber limiting surface of the first housing wall.

Due to the design of a compressor according to the invention, detachment and return flow of the compressed gas at the inlet into the high-pressure chamber can be reduced, in particular in the vicinity of the surge limit of the compressor characteristic diagram. In addition, in particular in the vicinity of the plug limit of the compressor map, the formation and / or intensity of blade tip vortex can be reduced, which can also have a positive effect on the compressor efficiency. Since backflow as well as blade tip vortex are primarily problems that occur in compressor impellers with shroud-open blade clearances, the inventive design can be particularly advantageous in a compressor with such open blade clearance spaces used.

Preferably, it can be provided that the second section directly adjoins the first section. However, it is also possible to arrange a further partial section running parallel to the second housing wall between the first and the second partial section.

Further preferably, it can be provided that the inlet section comprising the first and second partial sections of the first housing wall is relatively short relative to the radial overall length of the high-pressure chamber. In particular, it may be provided that the inlet section ends within the half, third or quarter enclosing the entrance to the high-pressure chamber.

In a preferred embodiment of the compressor according to the invention, it may be provided that the maximum housing wall approach in the first section corresponds as closely as possible to the axial width (i.e., the width in the direction parallel to the axis of rotation of the compressor impeller) of the impeller gap (at the transition from impeller gap to high-pressure space). This can represent an optimal compromise between the advantages that can be achieved by covering the impeller gap by means of the first section (reduction of backflow over the impeller gap and flow separation in the impeller) and the constriction of the flow cross section caused by this cover at the inlet of the high-pressure chamber. If the maximum housing wall approach in the first subsection is designed to be significantly smaller than the axial width of the impeller gap at the transition from the impeller gap to the high-pressure space, this can lead to the advantages basically achievable by means of the cover of the impeller gap not being fully exploited. If, on the other hand, the maximum housing wall approach in the first subsection is designed to be significantly larger than the axial width of the impeller gap at the transition from the impeller gap to the high-pressure space, then as a rule no relevant improvements are associated with the advantages that can be achieved by covering the impeller gap; However, the excessive constriction of the flow cross-section can then have a negative effect on the performance and / or the efficiency of the compressor, in particular in the case of a high mass flow rate of the compressed gas through the high-pressure space.

Due to the inventively provided, only moderate narrowing of the flow cross section at the inlet of the high pressure chamber higher flow rates and thus an increased mass flow rate are achieved in particular in the vicinity of the first housing wall, which can contribute to the stabilization and homogenization of the gas flow at the entrance to the high pressure chamber. This applies both to the area near the surge line and the stuffing limit of the associated compressor map.

Furthermore, it can preferably be provided that the inside of the second section is rectilinear with respect to a longitudinal section (along the axis of rotation of the compressor wheel) through the compressor (at least in sections, preferably over the entire length). This can in particular have a positive effect on the manufacturability of the compressor housing. Possibly, possibly without adverse effects, but may also be an embodiment in which the inside of the second portion is formed with respect to a longitudinal section through the compressor (at least in sections, optionally over the entire length) single or multiple curved.

On the other hand, it can be advantageously provided that the inner side of the first section is curved at least regionally (in particular in the region adjoined by the second section, if appropriate also over the entire length of the second section) with respect to a longitudinal section through the compressor, for example partially circular, is trained. This can have a particularly advantageous effect with regard to the flow resistance caused by the first subsection for the gas flowing into the high-pressure chamber. In this regard, may also be advantageous if the inside of the first section tangentially into the inside of the second section (again in each case based on a longitudinal section through the compressor) passes. As a result, an edge-shaped transition between the first subregion in the second subregion is avoided, which can lead to increased flow losses for the gas flowing through the high-pressure chamber. However, it is also possible to form the inside of the first section in a straight line with respect to a longitudinal section through the compressor, at least in regions, and possibly also over the entire length. This in turn can have an advantageous effect on the adjustability of the compressor housing.

In order to achieve the most advantageous covering effect of the first section for the impeller gap may further preferably be provided that the first section is formed at its end adjacent the impeller gap as parallel as possible (or coaxial with a circulating high pressure space around the impeller) with respect to a rotational axis of the compressor impeller. If the inside of the first section is designed to be curved at this end, the tangents resting on the inside of the first housing wall in the end points should be aligned correspondingly parallel to the axis of rotation. Deviations from the parallelism or coaxiality can be tolerated, possibly at the expense of a worsened effect of the cover of the impeller gap, these deviations should be as small as possible 10 °, preferably less than 5 ° and in particular less than 3 °.

For a most advantageous covering effect of the first section for the impeller gap may further be provided that the radial distance of the first section relative to the axis of rotation of the compressor wheel is designed to be as small as possible, without taking into account manufacturing and assembly tolerances and possible different, by temperature changes and / or inertial forces caused elongation to a contact of the impeller comes with this first portion of the first housing wall. A remaining gap between the cover of the impeller gap causing first portion of the first housing wall and the compressor impeller should therefore be as small as possible. If this radial distance is chosen unnecessarily large, this can be associated with a deterioration of the advantages caused by the cover of the impeller gap.

Further preferably, it can be provided that the second housing wall forms a shoulder which covers a portion of a hub of the compressor impeller. This shoulder, which may for example run parallel or coaxial with the axis of rotation of the compressor impeller, may in particular reduce a return flow of compressed gas via a gap formed between the second housing wall and the side of this hub adjacent thereto. Also, the radial distance of this paragraph should be as low as possible, without it comes under consideration of manufacturing and assembly tolerances and possible different elongations to a contact of the compressor impeller with this paragraph of the second housing wall are formed.

In such an embodiment of the compressor according to the invention can then be provided that the radial distance of the first section at its end adjacent the impeller gap is less than or equal to the radial distance of the paragraph at its distal end relative to the first housing wall. The radial distances in each case relate to the axis of rotation of the compressor impeller.

The compressor according to the invention can also be provided on the stroke side with a pinch. Accordingly, the second housing wall would be so far out in the direction of the first housing wall in one of the transition from the local impeller gap to the high-pressure chamber section that the second housing wall partially covers the exit edges of the compressor impeller.

The invention further relates to an exhaust gas turbocharger with a compressor according to the invention and a turbine. The turbine may include a turbine housing and a turbine runner disposed within a flow space of the turbine housing, the turbine runner being non-rotatably connected to the compressor runner, permitting transmission of a torque applied thereto as it flows through the turbine runner to rotationally drive the turbine runner a compression of a guided through the compressor gas can be achieved.

Furthermore, the invention also relates to an internal combustion engine having an internal combustion engine (in particular reciprocating internal combustion engine) forming one or more combustion chambers, a fresh gas train via which fresh gas can be supplied to the combustion chambers, an exhaust system via which exhaust gas can be discharged from the combustion chambers and a compressor or a compressor according to the invention exhaust gas turbocharger according to the invention, wherein the compressor (the exhaust gas turbocharger) in the fresh gas line and the turbine, if present, are integrated into the exhaust system.

The compressor according to the invention can also be configured differently (as via an exhaust gas turbine) drivable. For example, the compressor impeller may be drivable as an output shaft of an internal combustion engine (often referred to as a "compressor" in automotive technology) or an electric motor (often referred to as a "booster" in automotive engineering).

The compressor / exhaust gas turbocharger / internal combustion engine according to the invention can / be provided in particular for use in a motor vehicle, in particular a wheel-based motor vehicle.

An achievable by the inventive design higher efficiency level of the compressor can lead to a reduction in the required compressor power to represent the required by the engine boost pressure levels. This can have a positive effect on engine consumption, as there is less need for dust on the turbine side and thus a reduced Ausschiebearbeit at the end of the charge cycle must be applied. A too low mass flow extended surge limit allows for higher motorized cornering torque (LET: low end torque). An improvement of the charge pressure build-up at higher compressor mass flows can also lead to a reduction of the necessary ATL speed (n _ATL ) to represent the rated motor power P _max . The efficiency level of the compressor continues to have a decisive influence on the load jumping behavior of the internal combustion engine, especially in the low speed range. Already supposedly small improvements lead here as a result of the run-up self-amplification between compressor and turbine to optimize the dynamic response of the internal combustion engine by an accelerated boost pressure build-up.

The indefinite articles ("a", "an", "an" and "an"), in particular in the patent claims and in the description which generally explains the claims, are to be understood as such and not as number words. Corresponding to this concretized components are thus to be understood that they are present at least once and may be present more than once.

The invention will be explained in more detail with reference to embodiments shown in the drawings. In the drawings, each schematically shows:

1 : an embodiment of an internal combustion engine according to the invention;

2 a first embodiment of an exhaust gas turbocharger according to the invention;

3 : an enlarged view of the with III featured clipping in the 2 ;

4 A second embodiment of the compressor of the exhaust gas turbocharger in the III marked section in the 2 ;

5 A third embodiment of the compressor of the exhaust gas turbocharger in the III marked section in the 2 ;

6 A fourth embodiment of the compressor of the exhaust gas turbocharger in the III marked section in the 2 ;

7 the improvement achievable in a compressor map by the inventive design of a compressor;

8th by the embodiment according to the invention ( 8b ) achieves advantages with regard to the flow of the compressed gas in the region of the surge limit of the compressor map in comparison with a conventional compressor ( 8a ); and

9 by the embodiment according to the invention ( 9b ) of a compressor achievable advantages in terms of the flow of the compacted Gas near the plug boundary of the compressor map compared to a conventional compressor ( 9a ).

The in the 1 shown internal combustion engine comprises an operating according to the diesel or Otto principle internal combustion engine 10 , which is formed, for example, as a four-cylinder reciprocating internal combustion engine. The internal combustion engine 10 is about a fresh gas train 12 supplied with fresh gas (ambient air). For this purpose, the fresh gas after sucking from the environment by means of a compressor 14 compacted. The compressed fresh gas is then passed through a charge air cooler 16 guided, in which the heated as a result of compression fresh gas until reaching the desired temperature for entry into the engine 10 is cooled. About a suction pipe 18 the fresh gas enters combustion chambers 20 of the internal combustion engine 10 in which this or the oxygen contained therein in a known manner with directly into the combustion chambers 20 injected fuel is burned.

The resulting during the combustion of the fuel-fresh gas mixture exhaust gas is via an exhaust line 22 the internal combustion engine discharged. The exhaust system 22 includes an exhaust manifold 24 in which that from the individual combustion chambers 20 outflowing exhaust gas is merged, and one of them downstream turbine arranged 26 , The turbine 26 forms together with the compressor 14 an exhaust gas turbocharger and is by means of an adjustable bypass 28 (Wastegate) executed passable. The bypass 28 serves to, in certain leading to a large exhaust gas mass flow operating conditions of the internal combustion engine 10 , a portion of the exhaust mass flow at the turbine 26 To pass, so the boost pressure in the fresh gas train 12 to limit.

In the exhaust system 22 is downstream of the turbine 26 furthermore an exhaust gas treatment device 30 integrated. The exhaust treatment device 30 For example, it may include an oxidation catalyst and a particulate filter or a 3-way catalyst.

The Indian 2 represented, for example, in an internal combustion engine according to the 1 Exhaust gas turbochargers used include a turbine 26 and a compressor 14 , The turbine 10 includes a turbine runner 32 rotatable within one of a turbine housing 30 trained flow space is arranged. The turbine wheel 32 is about a wave 34 non-rotatable with a compressor impeller 36 of the compressor 14 connected. The compressor impeller 36 is within one of a compressor housing 38 rotatably mounted trained flow space. The turbine housing 30 , the compressor housing 38 as well as the wave 34 rotatably supporting shaft housing 40 may be formed integrally or separately (one or more parts).

The compressor 14 is designed as a radial compressor. Accordingly, this is starting from an inlet 42 and a low pressure room 44 the flow space in the axial direction with respect to the axis of rotation 46 of the compressor impeller 36 streamed by the gas to be compressed. The result of a rotating drive of the compressor impeller 36 compressed gas flows in the radial direction with respect to the axis of rotation 24 of the compressor impeller 36 from this and thus enters a compressor impeller 36 radially surrounding high-pressure chamber 48 the flow space and from there via a collecting space 50 into an outlet 52 of the compressor 14 , The high pressure room 48 serves as a diffuser, in which a targeted conversion of kinetic energy of the gas flowing through it is achieved in a static pneumatic pressure by slowing down the gas flow. In known manner forms the compressor impeller 36 a majority from a hub 62 extending blades 54 due to the rotation of the compressor impeller 36 that between each adjacent blades 54 arranged gas in the direction of the high-pressure chamber 48 displace, thereby simultaneously gas from the low pressure space 44 is sucked.

In conjunction with a compressor impeller 36 in an area that is between the blades 54 trained entrance edges 56 and exit edges 58 extends, radially surrounding the first housing wall 60 divides the compressor impeller 36 the flow space in the upstream of the compressor impeller 36 arranged low pressure space 44 and the downstream of the compressor impeller 36 arranged high-pressure chamber 48 , It is between this area of the compressor wheel 36 as well as the first housing wall 60 an impeller gap 64 designed in the sense of the best possible seal between the high-pressure chamber 48 and the low-pressure room 44 as narrow as possible, for example, with an axial width between 0.1 mm and 0.5 mm, preferably between 0.1 mm and 0.4 mm is formed.

The turbine 26 is designed as a radial turbine. This is starting from an inlet 66 , a distribution room 76 and one the turbine runner 32 radially surrounding high-pressure chamber 68 the flow space in the radial direction with respect to the axis of rotation 46 of the turbine wheel 32 from a gas, for example, exhaust gas of an internal combustion engine of a motor vehicle, flowed. This will turn the turbine wheel 32 driven in rotation. The exhaust gas flows from the turbine runner 32 subsequently in the axial direction with respect to the axis of rotation 46 and thus enters a low-pressure room 70 the flow space and from there into an outlet 72 the turbine 26 , Also the turbine wheel 32 forms a plurality of blades 74 out.

The 3 shows in an enlarged view in the 2 With III marked section of the compressor 14 , It can be seen that the first housing wall 60 of the compressor housing 38 located on the so-called Shroud side, in an entry section 80 of the high pressure room 48 that of the transition from the impeller gap 64 to the high pressure room 48 goes out, is formed such that this first housing wall 60 a second housing wall 78 that the first housing wall 60 within the high pressure room 48 in the direction of the axis of rotation 46 of the compressor impeller 36 is approaching, increasingly approaching. In one at the entrance section 80 subsequent further section 82 of the high pressure room 48 the two housing walls run 60 . 78 in contrast, essentially parallel to each other. This causes the width (ie the extension in the direction of the axis of rotation 46 ) of the high pressure space 48 at the entrance greater than in the outlet (ie the transition to the collection space 50 ) of the high pressure space 48 is what in known manner bring fluidic advantages and can have an advantageous effect on the compressor efficiency and the width of the compressor map. This further section 82 of the high pressure room 48 can in particular at least as long (radial extent relative to the axis of rotation 46 ) be formed as the inlet portion 80 ,

According to the invention, it is provided that the first housing wall 60 in this entry section 80 of the high pressure room 48 a first section 84 having the impeller gap 64 is adjacent and serves a cover of the impeller gap, including this first section 88 has the shape of a paragraph and thus within a relative (compared to a second subsection 86 ) short length (concretely in the 3 to 6 recognizable contour length of the high-pressure chamber 48 facing inside of the first housing wall 60 in a longitudinal section (along the axis of rotation 46 ) through the compressor 14 ) leads to a relatively (taking into account this length) housing wall approach x. The through the first section 84 The housing wall approach x effected corresponds approximately to the axial width c _{s of} the impeller gap 64 , A to the first section 84 subsequent second subsection 86 the first housing wall 60 (which is also an area of the entry section 80 of the high pressure room 48 represents), which acts as a pinch, leads to a housing wall approach y, which is usually greater than that of the first section 84 is (in the figures, these are shown for a better clarity, however, approximately the same size); but within a much longer length of this second subsection 86 compared to the length of the first section 84 ,

While in the 3 a curved and concrete partial circular (r _M constant) contour of the inside of the first section 84 is provided (which contour also tangential in the rectilinear contour of the second section 86 ), the show 4 and 5 alternative embodiments of inventive compressor 14 in which the corresponding contour of the respective first section 84 , as well as that of the associated second subsection 86 , is formed in a straight line. In this case, the first section runs 84 in the embodiment according to the 5 substantially parallel or coaxial (because of the closed about the compressor impeller 36 circulating high-pressure chamber 48 ), during the first section 84 in the embodiment according to the 4 with a positive (ie the extension of the first section 84 , starting from the impeller gap 64 adjacent end, has one in the direction of flow through the high-pressure chamber 48 pointing component) angle α _M obliquely with respect to the axis of rotation 46 is aligned. The 6 again shows an embodiment of a compressor according to the invention 14 with curved contour of the inside of the first section 84 (in longitudinal section), in which case, however, this contour is not part-circular (r _M not constant, eg teilelliptisch, teilparabolisch). Also in this embodiment is a straight line of the contour of the inside of the second section 86 provided, but in principle (ie in all compressors according to the invention) and curved courses of this contour of the second section 86 possible are. A rectilinear contour can be particularly advantageous in terms of the manufacturability of the compressor housing 38 be. On the other hand, a curved contour and, in particular, a tangential transition of the first subsection that is allowed thereby into the second subsection (or also of the second subsection into the further section 82 of the high pressure room 48 ) flow advantageous effect.

In all embodiments of inventive compressor according to the 3 to 6 forms the respective second housing wall 78 in only a small (minimum) radial distance from the compressor impeller 36 for example, 0.2 mm also leading to a Gehäusewandannäherung z paragraph 88 out, making the the high pressure room 48 forming portion of the second housing wall 78 a rear wall portion of the hub 62 of the compressor impeller 36 covered. This paragraph covers 88 but possibly not the exit edges 58 which is from the hub 62 starting in a three-dimensionally curved shape in the direction of the first housing wall 60 extending blades 54 , In the The drawings illustrated embodiments of inventive compressor 48 thus have no pinch on the so-called hub side, with such a can also be provided.

In the 3 is further shown that the radial distance r _{1 of} the parallel or coaxial (because of the closed to the compressor wheel 36 circumferential design paragraph 88 ) paragraph 88 the second housing wall 78 essentially corresponds to the radial distance that the first section 84 the first housing wall 60 at the impeller gap 64 adjacent end with respect to the axis of rotation 46 having. Basically, it is provided that these two radial distances should be made as small as possible, but with manufacturing and assembly tolerances and different elongations in the operation of the compressor 14 should be considered to make contact between the compressor impeller 36 and the compressor housing 38 to avoid. A curved (cf. 3 and 6 ) or oblique (cf. 4 ) Course of the contour of the first section 84 allows in principle, the radial distance of the first section 84 the first housing wall 60 at the impeller gap 64 adjacent end to form slightly smaller than the radial distance r _{1 of} the parallel or coaxial paragraph paragraph 88 the second housing wall 78 ,

In the embodiments of inventive compressor according to the 3 . 5 and 6 is further provided that the first section 84 the first housing wall at the impeller gap 64 adjacent end parallel or coaxial with respect to the axis of rotation 46 is aligned (in the curved contours according to the 3 and 6 represented by the arranged in the respective end point tangent 92 ).

The 7 shows the positive effects that an inventive design of a compressor 14 compared to conventional, but otherwise comparable compressors in terms of the compressor map can bring. The continuous lines illustrate the compressor map in a compressor according to the invention 14 , the dashed lines the compressor map in a conventional compressor with a Shroud pinch and the dotted lines the compressor map in a conventional compressor without pinch. It can be seen that not only an increase in the mass flows ṁ of the gas through the compressor at comparable pressure ratios (p ₂ / p ₁ ) but also a shift in the surge line 90 can be achieved in the direction of lower mass flows.

The 8th and 9 clarify also the fluidic improvements, which by an inventive design of a compressor 14 ( 8b and 9b ) compared to a conventional compressor with only one Shroud pinch ( 8a and 9a ) near the surge line ( 8th ) and near the Stopfgrenze ( 9 ) of the compressor map can be achieved.

Near the surge line 90 is provided by the inventively provided cover the impeller gap 64 peeling and backflow of gas flow on the shroud side at the entrance of the high pressure space 48 reduced, at the same time by the moderate narrowing of the flow cross-section higher flow rates and thus an increased mass flow rate for the gas is achieved. This also contributes to a stabilization and homogenization of the gas flow at the entrance of the high-pressure chamber 48 at.

In the vicinity of the plug boundary, the narrowed flow cross-section also achieves homogenization of the gas flow, which has a positive effect on the mass flow rate and a reduction in a backflow of already compressed gas.

LIST OF REFERENCE NUMBERS

10

internal combustion engine

12

Fresh gas line

14

compressor

16

Intercooler

18

suction tube

20

combustion chamber

22

exhaust gas line

24

exhaust manifold

26

turbine

28

bypass

30

turbine housing

32

turbine impeller

34

wave

36

compressor impeller

38

compressor housing

40

shaft housing

42

Inlet of the compressor

44

Low pressure chamber of the compressor

46

axis of rotation

48

High pressure chamber of the compressor

50

Collecting space of the compressor

52

Outlet of the compressor

54

Blade of the compressor

56

Entry edges of the compressor impeller

58

Exit edges of the compressor impeller

60

first housing wall of the compressor housing

62

Hub of the compressor impeller

64

Impeller gap of the compressor

66

Inlet of the turbine

68

High pressure chamber of the turbine

70

Low pressure chamber of the turbine

72

Outlet of the turbine

74

Blades of the turbine

76

Distribution room of the turbine

78

second housing wall of the compressor housing

80

Entry section of the high pressure chamber

82

another section of the high-pressure chamber

84

first section of the first housing wall

86

second section of the first housing wall

88

Paragraph of the second housing wall

90

surge line

92

Tangent in an endpoint of the first subsection

x

Housing wall approach in the first section

y

Housing wall approach in the second section

z

Housing wall approach through the shoulder of the second housing wall

c _s

Axial width of the impeller gap

r _M

Radius of curvature of the contour of the first section

r ₁

radial distance of the shoulder of the second housing wall

α _M

Angle of the rectilinear contour of the first section with respect to the axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 3260399A [0010]
• JP 2012-154204 A [0010]
• DE 1628227A [0011]
• EP 0402870 A1 [0012]
• US 2004/0146396 A1 [0013, 0013, 0013]

Claims (10)

Compressor ( 14 ) with a compressor housing ( 38 ) and within a flow space of the compressor housing ( 38 ) rotatably mounted compressor impeller ( 36 ), the flow space in a low-pressure space ( 44 ) and a high pressure room ( 48 ), wherein the compressor housing ( 38 ) a compressor impeller ( 36 ) between its entry edges ( 56 ) and its exit edges ( 58 ) radially surrounding, of this via an impeller gap ( 64 ) spaced first housing wall ( 60 ) and one of the first housing wall ( 60 ) with respect to the axial direction of the compressor impeller ( 36 ) in the high pressure room 48 opposite second housing wall ( 78 ), and wherein the first housing wall ( 60 ) in one of the transition from the impeller gap ( 64 ) to the high pressure room ( 48 ) outgoing entry section ( 80 ) of the high pressure space ( 48 ) so far in the direction of the second housing wall ( 78 ) extends that the first housing wall ( 60 ) the exit edges ( 58 ) of the compressor impeller ( 36 ) partially covered, characterized in that the first housing wall ( 60 ) within the entry section ( 80 ) a first subsection (( 4 ) and a second subsection ( 86 ), wherein the ratio of housing wall approach (x, y) to subsection length in the first subsection ( 84 ) greater than in the second subsection ( 86 ). Compressor according to claim 1, characterized in that the maximum housing wall approach (x, y) in the first section ( 84 ) of the axial width (c _s ) of the impeller gap ( 64 ) corresponds. Compressor ( 14 ) according to claim 1 or 2, characterized in that the contour of the inside of the second subsection ( 86 ) with respect to a longitudinal section through the compressor ( 14 ) is formed in a straight line. Compressor ( 14 ) according to one of the preceding claims, characterized in that the contour of the inside of the first section ( 84 ) with respect to a longitudinal section through the compressor ( 14 ) is curved at least partially formed. Compressor ( 14 ) according to claim 4, characterized in that the inside of the first section ( 86 ) tangentially into the inside of the second section ( 84 ) passes over. Compressor ( 14 ) according to one of the preceding claims, characterized in that the first subsection ( 84 ) at its the impeller gap ( 64 ) adjacent end parallel with respect to a rotation axis ( 46 ) of the compressor impeller ( 36 ) is trained. Compressor ( 14 ) according to one of the preceding claims, characterized in that the radial distance of the first section ( 84 ) with respect to the axis of rotation ( 46 ) of the compressor impeller ( 36 ) is formed as small as possible. Compressor ( 14 ) according to one of the preceding claims, characterized in that the second housing wall ( 78 ) a paragraph ( 88 ) forming a section of a hub ( 62 ) of the compressor impeller ( 36 ), wherein the radial distance of the first section ( 84 ) at its the impeller gap ( 64 ) adjacent end with respect to the axis of rotation ( 46 ) of the compressor impeller ( 36 ) less than or equal to the radial distance of the shoulder ( 88 ) at its with respect to the first housing wall ( 60 ) distal end is. Exhaust gas turbocharger with a compressor ( 14 ) according to one of the preceding claims and a turbine ( 26 ). Internal combustion engine with one or more combustion chambers ( 20 ) forming internal combustion engine ( 10 ), a fresh gas train ( 12 ), above the combustion chambers ( 20 ) Fresh gas can be supplied, an exhaust line ( 22 ), via the exhaust gas from the combustion chambers ( 20 ) and a compressor ( 14 ) according to one of claims 1 to 8 or an exhaust gas turbocharger according to claim 9, wherein the compressor ( 14 ) in the fresh gas line ( 12 ) is integrated.

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