DE102015209704A1 - Compressor with variable flow geometry - Google Patents

Abstract

The invention relates to a compressor arrangement (10) having a compressor impeller (50), an inflow passage (20) arranged upstream of the compressor impeller and an adjusting device (30) for changing a flow cross section of the inflow passage, such as a trim adjuster, the adjustment device comprising a diaphragm (14) arranged in the inflow passage (US Pat. 32) with a central aperture (34) and at least one further aperture in the form of an at least partially closable aperture window (36).

Description

The invention relates to a compressor arrangement having a compressor impeller, an inflow channel arranged upstream of the compressor impeller, and an adjusting device for changing a flow cross section of the inflow channel upstream of the compressor impeller, such as a trim plate, according to the preamble of claim 1. Such a compressor arrangement is part of an exhaust gas turbocharger for an internal combustion engine used.

To reduce fuel consumption, but also to increase the exhaust gas recirculation rate, exhaust gas turbochargers are used in internal combustion engines such as diesel and gasoline engines. With a compressor of the exhaust gas turbocharger, the fresh gas supplied via the fresh gas train of the internal combustion engine is compressed. In order to improve the variability and the response behavior of turbochargers, variable turbine geometries (VTG) are regularly used. A variable compressor geometry increases the variability of the charging system as another technology.

With the increasing charging level of modern internal combustion engines, the demands on the operating range (maps) of the turbocharger also increase. The background to this are the requirements of the internal combustion engine to achieve the maximum torque even at the lowest possible engine speeds, while at the same time constantly increasing the rated output. Particularly in the case of mono-turbocharged internal combustion engines, the turbocharger must ensure high charge pressures even at low air mass flows (range of the pumping limit) and at the same time enable the high air mass flow at rated power with the required boost pressures. Within the scope of these requirements, conventional turbochargers quickly reach their limits with regard to the possible operating range spread (characteristic map width) of the compressor and turbine stages. The VTG technology described above is already being used in many applications on the turbine side in order to enable the widest possible operating range of the turbine stage. Also on the compressor side, there are already numerous approaches to expand the operating range of the compressor stage by means of variability. In previous concepts, a swirl was imparted by means of a Vorleiteinrichtung the fresh air supplied to the compressor impeller, which improves the entry angle of the air flow to the compressor impeller or impeller. This measure counteracts flow separation at low mass flows.

To represent large cylinder fillings and engine torques, a small compressor trim is necessary, and to display high engine power at rated speed a large compressor trim. For this reason, it may be advantageous to provide a flow channel with trim variability. An adjustment device such as a trim plate serves to shift the surge limit of a compressor map in the direction of low mass flows at high pressure conditions. At the same time, a trim control can increase the compressor efficiency in the area of the pumping limit. For this purpose, a trim plate comprises an adjusting device, by means of which the inflow cross-section, in which the impeller of the compressor is flown, or the flow cross-section of the inflow channel in front of the impeller can be changed. Due to the nozzle effect of the trim adjuster achieved in this way, with increasing control engagement (reduction of the flow cross-section) the compressor inflow can be focused more strongly on the impeller-near flow cross-section of the compressor impeller. As a result, less fluid flows into the low-pulse and lossy region of the backflow bubble, and the core flow in the region near the hub is accelerated and thereby additionally stabilized. The acceleration of the flow in the region near the hub of the compressor also results in a suction-side displacement of the compressor inlet, which can contribute to a further stabilization of the flow. The stabilization of the core flow leads to the desired shift of the surge limit of the compressor map to lower mass flows. If not desired control intervention (Trimsteller fully open) as far as the entire cross-section of the inflow channel of the fresh gas line is released before the compressor, so that in the impeller flow as possible no additional friction or throttle losses. The compressor efficiency and the width of the compressor map are therefore not significantly adversely affected in the direction of Stopfgrenze by the Trimsteller.

A generic internal combustion engine is from the DE 10 2010 026 176 A1 known. The trim controller there comprises a cone, which in one embodiment consists of a plurality of lamellae. The lamellae are arranged in two layers, wherein the lamellae of each layer are spaced apart from one another and the two layers are offset in relation to each other in rotation so that the lamellae of one layer cover the distances between the lamellae of the respective other layer. By means of a displaceable in the longitudinal axial direction, the fins on the outside surrounding ring, the outlet cross-section of the cone forming ends of the fins can be moved radially. As a result, the size of the outlet cross-section and thus of the flow cross-section, in which the impeller of the compressor is flown changed.

The pamphlets DE 10 2011 121 996 B4 and DE 10 2013 003 418 A1 describe other ways to change the Flow cross-section of the inflow channel just before the compressor impeller by means of a Trimstellers. Known approaches of trimvariable compressors include a rotary ring, which controls a cam contour arranged in a circle lamellae. However, these fins are a weak point in the fatigue strength under extreme conditions; Furthermore, the reliability and controllability of the slats in transient engine operation is questionable.

The publication DE 10 2013 006 928 A1 discloses an exhaust gas turbocharger with a turbine arrangement with variable outlet cross-section.

In view of the described problems, it is the object of the present invention to provide a compressor arrangement with trim variability, which allows a particularly simple and reliable controllability of the flow cross section and a higher fatigue strength than the above-mentioned compressor arrangements of the prior art.

This object is achieved by a compressor arrangement of o.g. Art solved with the features characterized in claim 1. Advantageous embodiments thereof are the subject of the dependent claims and will become apparent from the following description of the invention.

The adjusting device of the compressor arrangement according to the invention has a diaphragm arranged in the inflow channel with a central diaphragm opening and at least one further diaphragm opening in the form of an at least partially closable diaphragm window. Unlike the aperture window, the central aperture is not necessarily closed and thus forms a of the fresh gas in the direction of the compressor impeller flowed through and always open trim channel, which allows a central flow of the compressor impeller.

The at least one aperture window, which is arranged radially further outward than the central aperture opening in the inflow channel, is preferably also completely closable, so that while maintaining a minimum inflow cross section through the central aperture opening, the flow cross section of the inflow channel can be closed or opened of the aperture window is enlarged or reduced. Thus, the compressor arrangement according to the invention is based on the operating principle of the constriction of the compressor inlet cross-section, whereby the flow inlet velocity is increased.

The invention is based on the recognition that complex structured trim plates are potentially more susceptible to disturbances, for example at extreme temperatures and soiling. In contrast, the adjustment device according to the invention, which has a diaphragm with at least two openings, namely the central trim opening forming the central aperture and the eccentrically arranged closable aperture window, particularly robust and thus stable against extreme loads. With regard to a simple and expedient construction, the diaphragm preferably comprises an inflow surface running transversely, in particular approximately perpendicularly to the flow direction in the inflow channel, in which the diaphragm windows are formed as openings. Aperture windows are adjustable by simple means and continuously as needed from the fully open position to the fully closed position, so that the compressor assembly according to the invention is particularly reliable controllable.

With regard to an improved variability and rapid controllability of the flow cross-sectional area of the inflow channel, it has proven to be advantageous for the aperture to have two, three or more, in particular approximately six, preferably closable aperture windows, which are arranged annularly around the central aperture. In this case, the central aperture is preferably circular, and the aperture windows each circulate substantially circular ring segment. In this case, a round cross-section of the inflow channel and the compressor impeller is used in the best possible way. Between the individual apertures connecting segments such as webs can be arranged, which separate the individual aperture windows from each other.

A particularly advantageous arrangement of the aperture windows is characterized in that of the n (n> 1) aperture windows, two adjacent aperture windows in each case enclose an angle of approximately 360 ° / n and / or each aperture window is configured in the form of a circular ring segment with a segment angle of 360 ° / 2n. In other words, corresponding geometries of the adjacent diaphragm windows have an angular spacing of 360 ° / n relative to the center axis of the adjustment device. Corresponding geometries are, for example, the aperture window centers, the right aperture window frames or the left aperture window frames.

A fast and reliable controllability of the inflow cross section by closing or opening the aperture window can be provided by opening, in particular by adjusting, in particular by turning, a movable closure member such as an annular disc against a stationary in the inflow passage aperture portion partially or completely closed or opened are. Preferably, the rotatable closure member applied upstream of the diaphragm on a substantially annular, flat inflow surface of the diaphragm, which has the aperture window, so that it is urged by the incoming fresh gas in the direction of the inflow surface. As a result, the stability of the adjusting device is increased overall.

According to a particularly preferred embodiment of the invention, the closing part is an adjacent to the fixed aperture portion, rotatable about the longitudinal axis of the inflow channel annular disc with a central aperture adapted to the central aperture and adapted to the aperture window, the central ring opening in each case partially circumferential annular windows, the analog shaped are like the aperture windows. In the fully open position of the adjusting device, the angular position of the annular disk is set up such that the diaphragm windows are substantially superposed with the identically shaped annular windows, so that all the diaphragm windows are completely open. In the fully closed position of the adjusting device, in which only the trim aperture forming central aperture is opened, the angular position of the annular disc is set up such that the aperture windows are covered by the webs between the annular windows. Any intermediate angle positions are advantageously possible. In the fully open position, the aperture windows allow the compressor to maintain its stuffing limit at equally high flow rates, which are typically shifted toward smaller throughputs with a smaller trim. Through the use of this turntable thus a continuous trim variability of the compressor inlet is possible. The rotatable disc has the advantages of ease of implementation, easy controllability, small size and high resistance to contamination, icing, etc.

As already indicated above, a trim channel with a comparatively small flow cross-section is formed by the central aperture. For this purpose, it has proved to be advantageous that the central aperture is formed in the form of a pipe section which opens toward a central section of the compressor impeller. In other words, the orifice downstream of the central orifice has a pipe section with a predetermined restricted trim cross section, through which the fresh gas can optionally be conducted at high flow velocity in the direction of a central section of the compressor impeller. Due to the nozzle-shaped design of this flow channel in front of the compressor impeller caused by the located in the inflow passage components hardly pressure losses. In the closed state of the aperture window, the flow cross section is reduced to the cross section of the pipe section. This allows the flow rate to be increased and the effective peripheral speed to be lowered at low flow rates, thereby shifting the surge line toward lower mass flows.

Particularly advantageous is an embodiment of the adjustment, in which between the inner wall of the inflow channel and an outer wall of the pipe section, a pipe section annularly surrounding Zuschaltkanal is formed, which can be flowed through by the at least one closable aperture window. Preferably, the interior of the pipe section through the central aperture is flowed, while the pipe section coaxial circumferential Zuschaltkanal is flowed through by the closable aperture window and thus switched on as needed or can be taken out of the flow path.

A further increase in the variability of the trim adjuster, which allows an improved adaptation to different operating ranges, can be achieved by forming in the wall of the pipe section at least one and preferably several passages, such as holes, which allow gas to flow through the pipe wall of the pipe section.

In a particularly preferred embodiment of the invention, these passages in the wall of the tube section are closable and openable, wherein preferably a continuous adjustment between a fully opened position and a fully closed position is possible.

Thus, the compressor assembly according to the invention on the one hand, the preferably closable aperture window and on the other also preferably closable flow passages in the wall of the pipe section, which separates the central trim channel of him annularly surrounding Zuschaltkanal. By the closable and openable passages thus the flow cross-sectional area between the Zuschaltkanal and the central Trimkannal can be adjusted as needed.

Since the wall of the pipe section is not perpendicular to the flow channel, but at least partially extends substantially in the direction of the flow channel, the passages do not necessarily extend perpendicularly through the wall of the pipe section, but can in flow-optimized manner obliquely with respect to the main flow direction of the central trim channel in the pipe section wall be introduced in order to avoid in this way turbulence of the air flowing from the inflow channel through the pipe section wall in the central trim channel air.

As well as the closable aperture window is preferably at least one and preferably all passages by adjusting, in particular by turning a movable cover with respect to the diaphragm fixed in the inflow partially or completely closed and opened. In the open position, passages of the cover with the passages in the pipe section wall are aligned so that a flow is possible, and in the closed position, the passages in the pipe section wall are covered by a closed wall of the cover and thus closed.

The cover member may include a sleeve portion abutting the inner surface of the wall of the tubular portion and rotatable about the central trim channel and having an array of passages corresponding to the array of apertures in the tubular portion and rotatable into a position aligned therewith.

With regard to a simple and reliable adjustability of the compressor assembly according to the invention, it has proven to be advantageous for the closure part to be formed integrally with the cover part. In other words, the closing part provided for closing the apertures is rotatable together with the cover member integrally formed therewith for closing the passages in the pipe section. In this case, the closure member may be formed in the form of approximately perpendicular to the main flow direction in the inflow passage annular disc, and / or the cover member may be formed in the form of a protruding from the annular disc in the pipe section sleeve paragraph.

The above-described high demands on the operating ranges of turbochargers can be particularly well met with a compressor assembly according to the invention, which is preferably infinitely adjustable by means of the adjustment in two, three or more operating positions, the operating positions are set up as follows:
In a first operating position, both the diaphragm windows and the pipe passages to prevent flow through are closed, so that the compressor impeller can be flowed over via the central trim channel. As a result, a good efficiency of the compressor can be achieved at low engine speed due to the highly narrowed flow cross-section in the inflow passage.

In a second operating position, at least one aperture window and preferably all the aperture windows are opened, and at least one pipe passage and preferably all pipe outlets are closed. In other words, the compressor impeller can be flown over both via the central trim channel and through the open aperture window via the Zuschaltkanal. As a result, a high air flow rate through the compressor is possible due to the large flow cross-section in the inflow passage, which is desired in particular at high engine speeds or under full load. Between the first and the second operating position, a stepless adjustment of the flow cross section is preferably possible.

In a third operating position, at least one aperture window and preferably all aperture windows are closed, and at least one tube passage and preferably all tube passages are open. In this third operating position, the compressor impeller via the central trim channel and via an exhaust gas recirculation described below, which opens into the Zuschaltkanal, due to the open passages flowable at high flow rate.

Another operating position, in which both the aperture windows and the passages are fully open, is not necessarily provided because such an operating position can potentially lead to turbulence and other flow problems of the gas flowing through the aperture windows and through the passages.

In today's internal combustion engines, a low-pressure exhaust gas recirculation (LP-EGR) is increasingly used to achieve legally prescribed emission limits. The exhaust gas taken downstream of a turbine of an exhaust-gas turbocharger is introduced via a feed in front of the compressor of the exhaust-gas turbocharger into the inflow channel of the fresh-air line and drawn in by it with the fresh gas. The introduction of the recirculated exhaust gas should be as close as possible in front of the compressor in order to avoid or keep unwanted condensate formation in the fresh gas. For regulating the LP EGR rate, a control valve is usually integrated into the LP EGR introduction prior to compressor entry.

The compressor arrangement according to the invention preferably has such exhaust gas recirculation (EGR), by means of which exhaust gas originating from the exhaust tract can be introduced into the inflow channel upstream of the compressor impeller. Both the supply line of the EGR and the setting device or the trim plate should be arranged as close as possible before the impeller of the compressor, which results in a competing installation space situation. Therefore, the exhaust gas recirculation of the compressor assembly according to the invention preferably opens in the region of the adjusting device in the intake passage. According to a particularly preferred embodiment, the exhaust gas recirculation for the introduction of Exhaust gas in the inflow passage downstream of the aperture window, ie between the aperture and impeller arranged.

The EGR admixture in the inflow duct is preferably set up variably. For this purpose, a control valve may be arranged in the exhaust gas recirculation supply line in order to be able to adjust the amount of exhaust gas to be supplied to the compressor.

From a constructive point of view, a laterally opening exhaust gas recirculation in the Zuschaltkanal, which rotates the pipe section coaxially, has proved to be particularly useful. Thus, the Zuschaltkanal be fed to the one by fresh gas through the aperture window and / or the other by exhaust gas on the exhaust gas recirculation, creating an individual and adapted to the needs admixture is possible.

According to a particularly preferred embodiment of the invention, an adjustment of the EGR admixture in the inflow passage through the above-described and preferably continuously openable and closable passages in the pipe section is possible. A high EGR rate can be adjusted through the opening of the passages in the pipe duct, since with open pipe passages a large flow cross-section between the exhaust gas recirculation and the central trim channel or the compressor impeller is formed.

In conventional ND Exhaust gas backflushes the use of an exhaust flap in the exhaust system to set a desired EGR rate is regularly required. Closing the exhaust flap leads to a higher exhaust back pressure in the exhaust tract and thus to a higher EGR rate, but with a higher fuel consumption associated with a closed exhaust flap.

Since the EGR rate in the compressor assembly according to the invention by means of the adjustment is adjustable, can be completely dispensed with the use of an exhaust valve when using the compressor assembly according to the invention, if necessary.

According to the invention, the EGR rate can be increased in a simple manner by opening the passages in the wall of the pipe section, since the flow cross section between the exhaust gas recirculation opening into the connection channel and the trim channel centrally flowing to the compressor rotor can thereby be increased. The above-explained third operating position with closed diaphragm windows and open passages thus serves in particular to provide a high LP EGR rate in predetermined speed and load ranges.

In other words, in the compressor arrangement according to the invention, the adjustment device can be designed to reduce and / or increase a flow cross section between the exhaust gas recirculation and the central trim channel or the compressor impeller.

The possibility of introducing exhaust gas into the fresh air tract via the auxiliary duct described above offers the option of map-wide EGR utilization due to the stepless control.

To provide the required drive power for the compressor at low mass flows, a combination with an additional electric compressor and / or a wastegate is possible.

The inventive combination of setting or Trimsteller and EGR introduction in the inflow of the fresh air line and the possible variable gas mixing thereby offer a particularly high variability and good controllability of the compressor inlet and the exhaust gas turbocharger as a whole.

A combination with an e-booster is possible alternatively or additionally.

In a particularly preferred embodiment of the invention, the compressor arrangement according to the invention has an e-booster or is combined with an e-booster in the form of an electric booster compressor. The e-booster can build up boost pressure right from the start, even at low engine speeds, and provide torque. The e-booster may be provided for electrically driving a compressor impeller and having an e-motor for this purpose.

In the range of low engine speeds, the boost pressure available through a turbocharger is limited. The main reasons for this are, on the one hand, the limited exhaust gas enthalpy available in this operating range and, on the other hand, the position of the surge limit of the compressor arrangement. A maximum exhaustion of the available exhaust gas enthalpy can occur in known turbochargers by appropriate control devices of the turbine, for example. Variable turbine geometry VTG, Wastegate WG, or VTG and WG in combination. The position of the surge limit limits the possible charge pressure build-up in the direction of small air mass flows (small engine speeds) by the then operating instabilities of the compressor assembly. Through the use of the trim adjuster, the surge line of the compressor assembly can be translated toward small mass air flows, thereby allowing higher boost pressures at low engine speeds. In engine operation exist to the stationary boost pressure requirements also dynamic boost pressure requirements due to acceleration or load changes. In such cases, the compressor assembly of the exhaust gas turbocharger, limited by its mechanical and thermal inertia and only delayed rising exhaust enthalpy, only with a limited system-specific dynamics generate boost pressure. These delays in the boost pressure build-up have a negative impact on the driving performance of the vehicle and in particular on the exhaust emissions during dynamic driving. In this context, the additional use of the e-booster for charging in a compressor assembly according to the invention is particularly advantageous:
The e-booster is decoupled from the exhaust enthalpy by the electric drive. The e-booster can be connected in series or parallel to the compressor arrangement, so that it can very dynamically make an additional contribution to the boost pressure or even generate it completely autonomously. In the case of a series connection, the charge pressure generated by the exhaust-gas turbocharger and the e-booster can exceed the steady-state boost pressure build-up that is possible by the turbocharger alone in the short term. In this case, the boost pressure provided corresponds to an operating point which lies in the compressor map on the left (in the direction of small mass flows) from the surge line. Such a boost pressure boost is particularly advantageous at low engine speeds (low-end torque) to improve the dynamic starting behavior of the vehicle. However, this boost pressure increase is limited in time by the available electrical energy from the vehicle electrical system as well as thermal operating limits of the e-booster. A stationary boost pressure and thus torque increase can only be achieved by an e-booster or only slightly.

In the case of a stationary torque increase, the operating point of the compressor assembly would shift dynamically into an unstable operating range beyond the surge limit after the e-booster has been switched off (after a maximum of 6-10 seconds). The turbocharger would suffer in the worst case by the onset of pumping a total loss.

Through the use of the trimmer, the desired torque increase in the region of low engine speeds can also be achieved stationarily in the compressor arrangement according to the invention by shifting the pumping limit. The combined use of an e-booster in conjunction with a compressor arrangement according to the invention with trim plate thus enables a dynamic (independent of the exhaust gas enthalpy) and stationary torque increase of the internal combustion engine in the low-speed range. As a result, the starting behavior of the vehicle can be positively influenced or the achievable nominal power can be increased with a mono-turbocharged internal combustion engine with the same starting performance. In order to enable the desired torque increase through the use of the trimmer also stationary, a part-load optimized turbine is necessary. Here, for example, partial-load-optimized aerodynamic designs of the turbine and / or corresponding control methods such as the VTG, WG described above are used individually or in combination. Alternative options for the Trimsteller under these boundary conditions (for example, Scavenging) are more complex and associated with higher costs.

A particularly streamlined design of the adjustment is possible in that a funnel-shaped taper of the inflow is provided downstream of the diaphragm and upstream of the compressor impeller. Preferably, the smallest flow diameter of the taper substantially corresponds to the diameter of the pipe section or is slightly larger than this. Alternatively or additionally, the smallest flow diameter of the taper is located immediately downstream of the end of the pipe section facing the compressor wheel, so that the taper forms the downstream end of the connection channel. Thus, the aperture windows form the upstream end of the Zuschaltkanals and the taper the downstream end of the Zuschaltkanals. At the downstream end of the Zuschaltkanals the flow path of the Zuschaltkanals - guided by the taper - extends radially inward, so that the fluid flowing through the Zuschaltkanal fluid is merged with the fluid flowing through the pipe section. This annular flow path of the connection channel, which is supplied radially from the outside to the central flow path, leads to a particularly stable and eddy-free flow behavior in the direction of the compressor impeller.

According to a further aspect, the present invention relates to an internal combustion engine having an internal combustion engine, an exhaust system, a fresh gas train and an exhaust gas turbocharger with a turbine integrated into the exhaust system and a compressor assembly according to the invention integrated in the fresh gas train.

A (LP) exhaust gas recirculation can be arranged between the exhaust gas line and the fresh gas line and open in the region of the adjusting device upstream of the compressor impeller into the inflow channel. In a particularly preferred embodiment of the invention, the exhaust gas recirculation opens in the central trim channel annular encircling Zuschaltkanal which can be flowed over the aperture window.

More preferably, the EGR rate is controllably or controllably established by means of the adjustment device. For this purpose, the adjusting device for changing the flow cross section between the exhaust gas recirculation or the Zuschaltkanal and the central trim channel can be established.

An internal combustion engine according to the invention does not necessarily have an exhaust valve for setting an EGR rate.

Preferably, the internal combustion engine has an e-booster in the form of an additional electric compressor, which may be connected in parallel or in series with the compressor arrangement.

Reference is made to the above statements, wherein the features described above can be used individually or in any combination in the internal combustion engine according to the invention, without being repeated here again.

According to a further aspect, the present invention relates to methods for operating an internal combustion engine according to the invention, in which an exhaust gas flow rate is set by an exhaust gas recirculation flowing into the fresh gas line upstream of the compressor impeller by means of the adjustment device of the compressor arrangement. By the adjustment device, a flow cross section between the exhaust gas recirculation and the compressor impeller can be adjusted. In a particularly preferred embodiment, the exhaust gas flow rate is adjusted by adjusting, in particular by turning a arranged in the inflow passage cover. The cover part can be designed to close passages between a central trim channel and a connecting channel which circulates in an annular manner and into which the exhaust gas recirculation opens.

In conventional LP exhaust gas recirculation, the EGR rate is adjusted regularly by means of an exhaust flap in the exhaust tract. According to the inventive method, the EGR rate is preferably set at least in predetermined operating and speed ranges not by means of the exhaust valve, but especially by means of the adjustment device in the inflow channel of the Frischgastrakts. Accordingly, eliminates the associated with the use of an exhaust flap higher fuel consumption due to the high exhaust back pressure.

• • Entfall der Abgasklappe,
• • Kombination eines Trimstellers mit der AGR-Einleitung und -Vermischung,
• • Besonders strömungsoptimierte Auslegung eines Trimstellers und folglich optimierte Anströmung des Verdichterlaufrads,
• • Kombination von Trimsteller und elektrischer Zusatzaufladung mittels E-Booster.

In particular, various embodiments of the invention provide some or all of the following advantages:

• • removal of the exhaust flap,
• Combination of a trim valve with EGR introduction and mixing,
• • Particularly flow-optimized design of a trim adjuster and consequently optimized flow of the compressor impeller,
• • Combination of Trimsteller and additional electric charging by means of e-booster.

The invention will be explained in more detail below with reference to the drawing. This shows in

1 An embodiment of a compressor assembly according to the invention in an open position in a perspective view,

2 the compressor assembly 1 in a closed position in a perspective view,

3 the compressor assembly 1 in an open position in a sectional view,

4 the compressor assembly 1 in a closed position in a sectional view,

5a D show various views of components of the adjusting device of the exemplary embodiment of a compressor arrangement according to the invention,

6 A second embodiment of a compressor assembly according to the invention in a schematic, illustrative view,

7 this in 6 shown second embodiment in an exploded view,

8th a perspective view of the second embodiment in three different operating positions I, II and III, and

9 a representation of the compressor map of the compressor assembly of the second embodiment.

An embodiment of a compressor assembly according to the invention 10 is in 1 shown in a perspective view. It is intended for installation in a fresh air line of an internal combustion engine with turbocharger. The exhaust gas turbocharger comprises a turbine (not shown) arranged in the exhaust tract and driven by the exhaust gas, and a compressor-driven radial compressor driven by the turbine 50 , which has a flow channel 20 With fresh gas can be flowed.

The compressor arrangement according to the invention 10 consists of the centrifugal compressor with compressor impeller 50 and from an upstream of the compressor impeller 50 arranged inflow channel 20 through which the compressor impeller 50 supplied fresh gas flows. The inflow channel 20 is downstream directly connected on the inlet side with the compressor and may be formed in the form of an optionally modified suction hood.

In the inflow channel 20 is an adjustment device 30 for changing a flow cross-sectional area of the inflow channel 20 arranged. The adjustment device 30 includes one in the inflow channel 20 fixed aperture 32 with a centrally present in the inflow port aperture 34 and several, the central aperture 34 circumferential aperture windows 36 , Through the central aperture 34 the fresh air enters a pipe section 39 with a predetermined (constant or varying in the flow direction) trim diameter X, which the fresh air towards a central portion of the impeller 50 leads. The through the central aperture 34 and the pipe section 39 formed trim channel is not closable in the embodiment described here and thus provides a minimum flow cross-sectional area for low mass flows ready. This trim channel is particularly clear in 5d shown the aperture 32 in a cross-sectional view shows.

The central aperture 34 has a gradually tapering in the flow direction inlet cross-section 31 on to allow a low-loss flow path for entering the trim channel fresh gas. In other words, the central aperture 34 funnel-shaped, with the transition between the aperture 34 and pipe section 39 is rounded.

How very clear in 5a is shown, extends around the central aperture 34 around an annular aperture extending substantially perpendicular to the flow direction 35 into which the aperture windows 36 are introduced. In the illustrated embodiment, the aperture windows 36 essentially shaped like a circular ring segment, so that the round cross section of the inflow channel 20 can be optimally exploited.

By way of example, six aperture windows are shown, with two adjacent aperture windows each enclosing a mutual angle of approximately 60 ° and each aperture window extending through an angle of approximately 30 °. The aperture area faces between two aperture windows 35 each annular segment-shaped webs, which also each extend at an angle of about 30 °.

At the aperture 35 is a closing part 38 in the form of a rotatably mounted annular disc, wherein the annular disc as well as the aperture 32 a central opening 44 and the central opening 44 ring-like circumferential ring windows 46 having. The trained as an annular disc closure 38 is particularly clear in 5b shown.

The locking part 38 serves to close and open the aperture window 36 by twisting around the central flow axis. In the 1 . 3 and 5c is the adjustment 30 in a fully open position, in which all the aperture windows 36 are permeated by fresh gas. In this position, the angular position corresponds to the aperture window 36 those of the ring windows 46 , One behind the aperture 35 existing, the pipe section 39 coaxial encircling inflow channel 25 , can through the aperture window 36 be flowed with fresh gas. At the downstream end of the inflow channel 25 becomes the through the inflow channel 25 running flow path through a rejuvenation established at this point 80 the outer wall of the inflow channel 20 radially inward with the through the pipe section 39 merging central flow path. The course of these two flow paths is in 3 on the one hand by the two central arrows and on the other by the two outer arrows (inflow channel 25 ) indicated.

In the 2 and 4 is the adjustment 30 in a closed position, in which only the central aperture 34 and thus the pipe section 39 is permeated by fresh gas. The trim is thereby reduced, whereby the flow rate can be raised. In this position are the aperture windows 36 each offset to the ring windows 46 arranged so that they are separated from the webs between the ring windows 46 be closed.

A particularly important feature is the supply line of an exhaust gas recirculation 70 through the exhaust gas from the exhaust tract into the fresh gas branch upstream of the compressor impeller 50 is initiated. The exhaust gas recirculation 70 opens in the area of the setting device 30 , between the aperture area 35 and the compressor impeller 50 , in the inflow channel 20 one. This is the result of the exhaust gas recirculation 70 supplied exhaust gas in the annular inflow channel 25 with the through the aperture window 36 mixed fresh gas mixed. Depending on the position of the closing part 38 and depending on the position of a control valve of the exhaust gas recirculation 70 Different mixing ratios are adjustable. Thus, the present invention includes a variable EGR admixture. This inventive combination of EGR introduction and mixing with the fresh gas while maintaining the minimum Frischgasströmungsdurchmessers through the central aperture 34 is to be particularly advantageous.

Further advantages of the invention are the particularly streamlined design of the adjustment 30 , A simple controllability by rotation of the annular disc to each predetermined angle, the particularly high robustness of the diaphragm and the annular disc (high adjustment forces are also applied, for example, in icing and contamination) and the small space required.

The 6 to 8th show a second embodiment of a compressor assembly according to the invention 100 , In 6 is the compressor arrangement 100 shown in a schematic sectional view, in 7 is the compressor arrangement 100 shown in an exploded view, and in 8th are different operating positions of the compressor assembly 100 shown in a partially perspective and partially in section view.

The second embodiment corresponds in essential points to the first embodiment, so that reference may be made to the above statements. The compressor arrangement 100 is intended for installation in a fresh air train of an internal combustion engine with turbocharger. The exhaust gas turbocharger comprises a turbine (not shown) arranged in the exhaust tract and driven by the exhaust gas, and a turbine compressor driven by the centrifugal compressor with the compressor impeller 150 , that over the inflow channel 120 With fresh gas can be flowed.

In the inflow channel 120 is an adjustment device 130 for changing a flow cross-sectional area of the inflow channel 120 arranged. The adjustment device 130 includes one in the inflow channel 120 fixed aperture 132 with a centrally present in the inflow port aperture 134 and several aperture windows 136 , in the 7 are recognizable. Through the central aperture 134 the fresh air enters a pipe section 139 with a given trim diameter, which directs the fresh air toward a central portion of the impeller 150 leads. The through the central aperture 134 and the pipe section 139 formed central trim channel is not closable as in the first embodiment and thus provides a minimum flow cross-sectional area for low mass flows ready.

How very clear in 7 is shown, extends around the central aperture 134 around an annular aperture extending substantially perpendicular to the flow direction 135 into which the aperture windows 136 are introduced. In the illustrated embodiment, the aperture windows 136 essentially shaped like a circular ring segment, so that the round cross section of the inflow channel 20 can be optimally exploited. By way of example, six aperture windows are shown, with two adjacent aperture windows each enclosing a mutual angle of approximately 60 ° and each aperture window extending through an angle of approximately 30 °. The aperture area faces between two aperture windows 135 each annular segment-shaped webs, which also each extend at an angle of about 30 °. A deviating arrangement of the aperture window is also conceivable.

At the aperture 135 is a closing part 138 in the form of a rotatably mounted annular disc, wherein the annular disc as well as the aperture 132 a central opening 144 and the central opening 144 ring-like circumferential ring windows 146 having. The locking part 138 serves to close and open the aperture window 136 by twisting around the central flow axis. In the in 8th Central view is the adjustment 130 in a second operating position II, in which all the aperture windows 136 are permeated by fresh gas. In this position, the angular position corresponds to the aperture window 136 those of the ring windows 146 , One behind the aperture 135 existing, the pipe section 139 coaxial encircling inflow channel 125 , can through the aperture window 136 be flowed with fresh gas. At the downstream end of the inflow channel 125 becomes the through the inflow channel 125 running flow path through a rejuvenation established at this point 180 the outer wall of the inflow channel 120 radially inward with the through the pipe section 139 merging central flow path.

In the in 8th left and right illustrated first and third operating positions I and III, the aperture windows are closed, while the central aperture 134 and thus the pipe section forming the central trim channel 139 is permeated by fresh gas. The trim is thereby reduced, whereby the flow rate can be raised. In this position are the aperture windows 136 each offset to the ring windows 146 arranged so that they are separated from the webs between the ring windows 146 be closed.

A particularly important feature is the supply line of an exhaust gas recirculation 170 through the exhaust gas from the exhaust tract into the fresh gas branch upstream of the compressor impeller 150 is initiated. The exhaust gas recirculation 170 opens in the area of the setting device 130 , between the aperture area 135 and the compressor impeller 150 , in the inflow channel 120 one. This is the result of the exhaust gas recirculation 170 supplied exhaust particularly well with the supplied fresh gas mixable, which flows through the central trim channel.

Compared to the first embodiment, the adjustment device 130 of the second embodiment, the following differences: The pipe section 139 in the flow channel 120 arranged aperture 132 has no closed pipe wall (see in 6 For comparison purposes, right panel shown above 32 ), but several the pipe wall passing through passages 160 in the form of holes. The passages 160 increase the flow area between the exhaust gas recirculation 170 and the central trim channel, thereby increasing the EGR rate.

In 6 is this modified panel 132 shown on the bottom right in a side view, wherein the flow-optimized shaped passages 160 are recognizable.

The passages 160 are by means of a cover 162 openable and lockable, in order to be able to adjust the EGR rate as needed. The cover part 162 is in the form of a one-piece with the annular disc-shaped closing part 138 formed sleeve paragraph formed in the pipe section 139 the aperture 132 protrudes and to cover the passages 160 is provided in a closed position.

This is done by turning the locking part 138 on the one hand the aperture windows 136 openable and lockable and on the other the passages 160 openable and closable, the fluid connection between the Zuschaltkanal 125 and the central trim channel.

In the second embodiment, the passages 160 in a spatial arrangement in the wall of the pipe section 139 introduced, in combination with the spatial arrangement of the aperture window 136 The following three operating positions are possible 8th are shown: a first operating position I (first rotational position of the closing part 138 ), in which both the aperture windows 136 as well as the passages 160 from the closing part 138 or the sleeve-like protruding cover part 162 are closed, the central trim channel is open, however; a second operating position II (second rotational position of the closing part 138 , here twisted by 30 ° from the first operating position), in which the aperture windows 136 with the ring windows 146 are aligned and thus open, but the passages 160 through the cover part 162 are closed; and a third operating position III (third rotational position of the closing part 138 , here twisted by 30 ° relative to the second operating position), in which the aperture windows 136 are closed, the passages 160 however, are open to provide a high EGR rate. Stepless intermediate positions are possible.

In 9 are shown by the second embodiment achievable efficiency advantages. You can see the compressor map of the base ( 193 ) and the compressor assembly according to the invention. The X-axis designates the reduced volume flow in m ³ / s ( 191 ), and the Y axis denotes the compressor pressure ratio ( 192 ). The basic map is through 193 , the full load characteristic through 194 , the difference map for optimized variant according to Embodiment 2 by 195 and the neutral line through 196 designated. The advantages of the invention are particularly evident up to a speed of about 1750 min ^-1 . By means of the lines 197 the efficiency advantages are highlighted by optimizing the Schaufelradanströmung.

It has been found that there is a potential for eliminating the exhaust flap. In an EGR rate variation at a speed of 2000 min ^-1 and a mean effective pressure of 4 bar is apparent that through the EGR operating position of the trimvariablen compressor arrangement, the exhaust flap substantially longer or completely (with respect to the basic EGR rate ) can remain open.

LIST OF REFERENCE NUMBERS

10, 100

compressor assembly

20, 120

inflow

25, 125

Zuschaltkanal

30, 130

adjustment

31, 131

Inlet cross-section

32, 132

cover

34, 134

central aperture

35, 135

aperture area

36, 136

iris window

38, 138

A sealing / washer

39, 139

pipe section

44, 144

central ring opening

46, 146

ring window

50, 150

compressor impeller

160

flow passages

162

cover

70, 170

Exhaust gas recirculation

80, 180

funnel-shaped rejuvenation

191

red. flow

192

dead. Compressor pressure ratio

193

Base map

194

Full load characteristic 110 kW

195

Difference map η _closed - η _open

196

neutral line

197

Efficiency benefits

D

smallest flow diameter of the taper

X

Trimdurchmesser

I

first operating position

II

second operating position

III

third operating position

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

• DE 102010026176 A1 [0005]
• DE 102011121996 B4 [0006]
• DE 102013003418 A1 [0006]
• DE 102013006928 A1 [0007]

Claims (17)

Compressor arrangement ( 10 . 100 ) for an internal combustion engine with a compressor impeller ( 50 . 150 ), one upstream of the compressor impeller ( 50 . 150 ) arranged inflow channel ( 20 . 120 ) and an adjusting device ( 30 . 130 ) for changing a flow cross-sectional area of the inflow channel ( 20 . 120 ), characterized in that the adjusting device ( 30 . 130 ) one in the inflow channel ( 20 . 120 ) arranged aperture ( 32 . 132 ) with a central aperture ( 34 . 134 ) and at least one further aperture in the form of an at least partially closable aperture window ( 36 . 136 ) having. Compressor arrangement according to claim 1, characterized in that the diaphragm ( 32 . 132 ) two, three or more, in particular about six lockable aperture windows ( 36 . 136 ) which annularly around the central aperture ( 34 . 134 ) are arranged around. Compressor arrangement according to claim 2, characterized in that of the n diaphragm windows ( 36 . 136 ) two adjacent aperture windows in each case enclose an angle of approximately 360 ° / n and / or each aperture window is arranged in the form of a circular ring segment with a segment angle of 360 ° / 2n. Compressor arrangement according to at least one of the preceding claims, characterized in that the aperture windows ( 36 . 136 ) preferably at the same time by adjustment, in particular by rotation, of a movable Verschließteils ( 38 . 138 ) with respect to the diaphragm fixed in the inflow channel ( 32 . 132 ) are partially or completely closed or openable. Compressor arrangement according to claim 4, characterized in that the closing part ( 38 . 138 ) one at an approximately perpendicular to the flow direction diaphragm surface ( 35 . 135 ) can be applied rotatable annular disc, with a to the central aperture ( 34 . 134 ) adapted central ring opening ( 44 . 144 ) and the aperture windows ( 36 . 136 ) adapted, the central ring opening in each case partially circumferential annular windows ( 46 . 146 ). Compressor arrangement according to at least one of the preceding claims, characterized in that the central aperture ( 34 . 134 ) one to a central portion of the compressor impeller ( 50 . 150 ) opening out pipe section ( 39 . 139 ) is formed, wherein between an inner wall of the inflow channel ( 20 . 120 ) and an outer wall of the pipe section a the pipe section annular circulating Zuschaltkanal ( 25 . 125 ) formed by the at least one closable aperture window ( 36 . 136 ) can be flowed on. Compressor arrangement according to claim 6, characterized by one or more preferably closable flow passages ( 160 ) in the outer wall of the pipe section ( 139 ). Compressor arrangement according to claim 7, characterized in that the flow passages ( 160 ) preferably simultaneously by adjusting, in particular by rotating a movable cover ( 162 ) with respect to the diaphragm fixed in the inflow channel ( 132 ) are partially or completely closed or openable. Compressor arrangement according to claims 4 and 8, characterized in that the closing part ( 138 ) in one piece with the cover ( 162 ), wherein the cover part in the manner of a sleeve paragraph starting from the closing part in the pipe section ( 139 ) protrudes. Compressor arrangement according to one of claims 7 to 9, characterized in that the compressor arrangement in a first operating position (I), in which both the aperture window ( 136 ) as well as the pipe outlets ( 160 ) are closed to prevent flow, in a second operating position (II), in which at least one and preferably all aperture windows ( 136 ) and at least one and preferably all pipe outlets ( 160 ) are closed, and / or in a third operating position (III) is adjustable, in the at least one and preferably all aperture windows ( 136 ) closed and at least one and preferably all pipe outlets ( 160 ) are open. Compressor arrangement according to at least one of the preceding claims, characterized by exhaust gas recirculation ( 70 . 170 ), by the exhaust gas upstream of the compressor impeller ( 50 . 150 ) in the region of the adjusting device ( 30 . 130 ), preferably downstream of the aperture window ( 36 . 136 ), into the inflow channel ( 20 . 120 ) can be introduced. Compressor arrangement according to claim 6 or one of claim 6 dependent claim and claim 11, characterized in that the exhaust gas recirculation ( 70 . 170 ) into the connection channel ( 25 . 125 ) opens. Compressor arrangement according to claim 11 or 12, characterized in that the adjusting device ( 130 ) is arranged to vary a flow cross-sectional area between the exhaust gas recirculation and the compressor impeller. Compressor arrangement according to one of the preceding claims, characterized by a funnel-shaped rejuvenation ( 80 . 180 ) of the inflow channel ( 20 . 120 ) downstream of the diaphragm ( 32 . 132 ) and upstream of the compressor impeller ( 50 . 150 ), wherein preferably the smallest flow diameter (D) of the taper ( 80 . 180 ) substantially the diameter of the pipe section ( 39 . 139 ) and / or immediately downstream of the compressor impeller ( 50 . 150 ) facing the end of the pipe section ( 39 . 139 ), so that the rejuvenation ( 80 . 180 ) the connection channel ( 25 . 125 ) bounded downstream.  Compressor arrangement according to one of the preceding claims, characterized by an electrically driven e-booster for increasing a supercharger pressure which can be provided by the compressor arrangement. Internal combustion engine with an internal combustion engine, an exhaust system, a fresh gas train and an exhaust gas turbocharger with a turbine integrated into the exhaust system and a compressor arrangement integrated into the fresh gas train ( 10 ) according to any one of the preceding claims. A method of operating an internal combustion engine according to claim 16, wherein an exhaust gas flow rate through an upstream of the compressor impeller ( 150 ) in the fresh gas line opening exhaust gas recirculation ( 170 ) by means of the adjusting device ( 130 ) of the compressor assembly and preferably is not adjusted by means of an exhaust flap.

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