WO2012072183A1

WO2012072183A1 - Charging device for an internal combustion engine

Info

Publication number: WO2012072183A1
Application number: PCT/EP2011/005661
Authority: WO
Inventors: Michael Stiller; Kai Kanning; Siegfried Sumser; Tobias Lorenz
Original assignee: Daimler Ag
Priority date: 2010-12-01
Filing date: 2011-11-11
Publication date: 2012-06-07
Also published as: DE102010053057A1

Abstract

The invention relates to a charging device (19) for an internal combustion engine (10) of a motor vehicle, comprising at least one turbocharger (18) that comprises a turbine housing (90) which is arranged in an exhaust gas tract (31) of the internal combustion engine (10), through which exhaust gas of the internal combustion engine (10) can flow, and in which a turbine wheel (94) that can be supplied with the exhaust gas is rotatably received. The charging device also comprises at least one feeding device (45) by means of which additional air can be fed to the turbocharger (18), said feeding device (45) having at least one introduction point (52) which lies in the exhaust gas tract (31) and via which the turbine wheel (94) can be supplied with the additional air.

Description

Charging device for an internal combustion engine

The invention relates to a charging device for an internal combustion engine specified in the preamble of claim 1. Art.

DE 198 33 134 C1 discloses a method for operating a charged

Internal combustion engine, which has an exhaust gas turbocharger with a compressor in one

Has intake and a turbine in an exhaust line and a gas storage for receiving compressed gas. The gas storage is charged or discharged depending on the operating state of the internal combustion engine, the gas storage is filled by the exhaust back pressure upstream of the turbine with exhaust gas, which additionally drives the exhaust gas turbocharger when unloading the gas storage. When discharging the gas storage, its storage contents can be fed to the exhaust gas line upstream of the turbine.

DE 101 58 874 A1 discloses an exhaust gas turbocharger for an internal combustion engine, with an exhaust gas turbine in the exhaust line and a compressor in the intake, wherein the compressor comprises a compressor in an inflow passage in the compressor housing, and with an additional air feeding device associated with the compressor area. The additional air feed device comprises an additional air channel in the compressor housing for the supply of additional air, which is to be introduced via an injection opening in the wall of the inflow channel compressed into the inflow region of the compressor wheel.

The known solutions have further potential to improve the instationary behavior of supercharged internal combustion engines.

It is therefore an object of the present invention, a charging device of a

To provide internal combustion engine, which allows an improved transient behavior of the internal combustion engine. This object is achieved by a charging device for an internal combustion engine having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims.

Such a charging device for an internal combustion engine of a motor vehicle comprises at least one exhaust gas turbocharger which, in an exhaust tract of the

Internal combustion engine arranged and exhaust of the

Internal combustion engine through-flow turbine housing comprises. By doing

Turbine housing is rotatably received by the exhaust gas acted upon and thereby driven turbine wheel. The charging device further comprises at least one supply device, by means of which the exhaust gas turbocharger additional air can be supplied.

According to the invention, it is provided that the feed device has at least one introduction point arranged in the exhaust tract, via which the turbine wheel is connected to the

Driving desselbigen can be acted upon with the additional air. This can do that

Turbine and thus the exhaust gas turbocharger in particular in addition to the

Actuation of the turbine wheel to be driven with the exhaust gas. This makes it possible for a compressor of the exhaust gas turbocharger, even in low load ranges, in which only small mass flows of the exhaust gas flow through the turbine housing and drive the turbine, via which to drive the turbine advantageously and at high rotational speeds. Thus, the compressor can also be used in the low load ranges of

Combusting internal combustion engines supplied air particularly well. As a result, high power and torque can be realized.

For compressing the air, the compressor comprises, for example, a compressor wheel rotatably connected to a shaft, wherein the turbine wheel is also connected in a rotationally fixed manner to the shaft. If the turbine wheel is exposed to exhaust gas and from this

driven, so drives the turbine via the shaft and the compressor, which then flows through a compressor housing and the

Internal combustion engines can compress supplied air. The drive of the turbine wheel and thus the compressor wheel thus depends in particular on the mass flow of the exhaust gas, which flows through the turbine housing and the turbine wheel flows. In particular, in low load ranges of the internal combustion engine, it may come to low mass flows of the exhaust gas, so that in particular the high load ranges and therefore possibly a high moment of inertia having turbine wheel can not be driven as desired. This only happens an inert pressure build-up of the compressor and thus an inert power or torque buildup of the internal combustion engine. This leads to a

undesirable driving behavior, which is noticeable as a so-called turbo lag.

To this disadvantageous transient behavior of the internal combustion engine

especially at a transition from low to higher

To avoid load areas or at least to improve, it is now possible by means of the charging device according to the invention, the turbine wheel and thus the

To drive compressor in particular in addition to the additional air. So it comes in lower load ranges to a particularly rapid pressure build-up of the compressor and thus to a particularly rapid provision of a desired power or a desired torque of the internal combustion engine. The so-called turbo lag is thereby avoided or at least reduced.

The charging device according to the invention has in particular the advantage that an introduction of the additional air for driving the exhaust gas turbocharger or the turbine wheel is not provided an intake tract but in the exhaust gas tract of the internal combustion engine. The introduction of additional air for driving the exhaust gas turbocharger in the intake tract has the disadvantage that in this solution, at least one

Valve device must be provided in the intake tract, so that it is none

Return flow of the introduced into the intake air additional air to the compressor also arranged in the intake of the exhaust gas turbocharger comes. The valve device obstructs the intake tract, so that it does not come to this backflow. However, this means that the compressor delivers against the closed valve direction and thus against a closed system, so that the compressor exceeds its surge limit, if no additional blow-off device is provided upstream of the valve.

This problem is avoided in the charging device according to the invention. In addition, with the charging device according to the invention it is possible to direct the additional air at least substantially directly to the turbine wheel and thus to be able to drive it particularly efficiently. In addition, the additional air in the charging device according to the invention can be introduced into the exhaust tract at a substantially higher pressure than in the intake tract, so that the turbine wheel can be driven in a particularly advantageous manner. In addition, no complex pressure control is needed. Furthermore, it is avoided that the compressor reaches its pumping limit or even this

exceeds. To illustrate a particularly good transient behavior of the

Internal combustion engines can also be a so-called variable turbine used as the turbine of the exhaust gas turbocharger. Such a variable turbine comprises an adjusting device, by means of which flow conditions in the flow direction of the exhaust gas upstream of the turbine wheel and / or stromabigen are influenced. The adjusting device makes it possible, for example, at least one

Set flow cross-section upstream of the turbine wheel, i. to increase or decrease in comparison. Thus, the turbine to different

Operating points of the internal combustion engine to be adjusted efficiency level.

The charging device according to the invention has the further advantage that such adjusting devices and thus additional components are not necessarily required to realize a very good instationary behavior of the internal combustion engine. As a result, the charging device according to the invention has a low number of parts, low weight and low costs.

The charging device according to the invention can be used in internal combustion engines for passenger cars. However, the advantage of the low cost comes especially in internal combustion engine for commercial vehicles to fruition, since their cost-effectiveness depends in particular on the cost, which can be kept low by the charging device according to the invention. Furthermore, the charging device allows efficient operation of the

Internal combustion engine, so that it has only a low fuel consumption and low C0 ₂ emissions. This also keeps the operating costs of the motor vehicle, especially the utility vehicle, low.

The introduction of the additional air in the exhaust gas in the flow direction of the exhaust gas upstream of the turbine causes due to the flow rate of the turbine in addition to an increase in throughput and an increase in the

Turbine pressure ratio (pressure upstream of the turbine wheel in relation to the pressure downstream of the turbine wheel), whereby a disproportionate increase in the turbine power is effected by means of the increased and made available for the exhaust gas turbocharger Ausschubarbeit the internal combustion engine. The effect of the desired faster run-up (speed acceleration) of the compressor wheel in particular in the

Transition from low to contrast higher load ranges is the result, what with the very good transient behavior and the very good handling of the

Internal combustion engine goes along. With the realization of a very advantageous torque build-up of the internal combustion engine due to the very advantageous boost pressure build-up is also a reduction of particulate emissions, especially during

Acceleration phases of the internal combustion engine accompanied. Another effect is that in the exhaust tract, in particular in an outlet manifold of the

Internal combustion engine, introduced, in particular blown, additional air, so to speak, as residual air of the exhaust gas on still open exhaust valves of the

Internal combustion engine from the outlet derselbigen forth in at least one combustion chamber, in particular a cylinder, the internal combustion engine can get. This represents a further development option for the internal combustion engine, in particular with regard to its emission behavior. This is especially the case if the introduction or feeding of the additional air, which takes place, for example, in clocked fashion, is oriented to opening times of gas exchange valves, in particular of exhaust valves, of the internal combustion engine.

In an advantageous embodiment of the invention, the discharge point is at least partially arranged upstream of the turbine wheel. Thus, the turbine can be supplied particularly well the additional air and the turbine wheel are particularly efficient driven by the additional air. Thus, it is possible to supply the additional air to the turbine wheel on the outer peripheral side and in the radial direction at least substantially over the circumference of the turbine wheel in order to be able to drive the turbine wheel in a particularly streamlined manner.

It is also possible that the discharge point is at least partially disposed in the axial direction of the turbine wheel in at least partially overlapping with a Radrücken of the turbine wheel, wherein the Radrücken is advantageously designed to be open. Thus, the additional air can be supplied to the turbine wheel at least substantially axially and the additional air can first at least substantially axially flow from the particular open Radrücken forth vanes of the turbine wheel and thereby drive the turbine wheel.

In a further advantageous embodiment of the invention, the turbine wheel by means of the feed device with compressed air as the additional air can be acted upon. In other words, the additional air is pressurized air

(Compressed air), where the pressure is higher than the ambient pressure. The present as compressed air additional air is compressed, for example by means of an air compressor to a pressure of 10 to 12 bar inclusive and optionally in one Storage device, such as a pressure vessel, stored, in particular cached. The storage device communicates fluidically with the point of introduction, so that the additional compressed air present as compressed air can flow from the storage device to the point of introduction and flow to the turbine wheel. The high pressure of the additional air has the advantage that thereby the turbine wheel and thus the compressor wheel in particular in low load ranges of

Internal combustion engine can be driven particularly well, which is associated with a particularly advantageous compression of the air and thus with a particularly advantageous torque structure of the internal combustion engine.

Advantageously, the feed device comprises a valve device by means of which the additional air can be introduced as required into the exhaust tract and the

Turbine is fed. This valve device is, for example, a clocked valve. By means of such a clocked valve, for example, a connecting line of the storage device and the discharge point is at least in

Substantially completely fluidly blocked and at least substantially completely fluidically releasable, so that a maximum flow cross-section is released.

It is equally possible, such a clocked valve with at least one

Insert intermediate position in which the connecting line is only partially fluidly released and a flow cross-section is set, which is smaller than the maximum flow cross-section. Advantageously, a plurality of such intermediate positions are adjustable. It is also possible to use as the valve means a so-called black and white valve, which completely blocks the connection line fluidically or can release completely fluid.

Intermediate positions are not provided. The clocked valve allows a very precise supply of air into the exhaust system, while the black and white valve has very low cost.

To provide the additional air as compressed air, for example, the air compressor or another compressor for representing the compressed air of the

Internal combustion engine drivable. It is equally possible that the compressor by means of a different engine from the internal combustion engine,

For example, an electric motor as an auxiliary drive unit (Auxiliary Power Unit) can be driven. In a further advantageous embodiment of the invention, the feed device comprises a swirl device, by means of which the additional air which acts on the turbine wheel is to be provided with a swirl. In other words, the additional air flowing to the turbine wheel has a twist and thus a high

Flow energy, so that the turbine wheel and thus the compressor wheel are particularly efficient to drive. This leads to a particularly good and fast

Torque buildup and thus a very good transient behavior of

Internal combustion engine.

Substituting a pressure ratio between the storage device and the discharge point in the exhaust tract for generating high flow velocities of the additional air, which is supplied under high swirl at least substantially directly to the turbine, is in addition to the increase of the average

Turbine total pressure ratio and the average Durchströmmasse locally,

For example, in a Radantrittsdüsenbereich, at relatively low static pressure, an effective implementation of an energy content of the storage device or the

Mass flow of additional air directly over the Euler turbine equation advantageously allows.

It is advantageously provided that the discharge point is at least partially disposed at the height of a largest diameter of the turbine wheel. This leads to a particularly efficient implementation of the energy contained in the flow of the additional air for driving the turbine wheel, whereby a particularly good transient behavior of the internal combustion engine is shown.

The turbine power is proportional to the inlet temperature of an incoming and acting on the turbine wheel gas for driving the turbine wheel, which is the exhaust gas of the internal combustion engine and / or the additional air in the charging device according to the invention. In an advantageous embodiment of the invention, therefore, at least one heating device is provided, by means of which the additional air can be heated upstream of the turbine wheel. As a result, an energy contribution of the additional air for driving the turbine wheel is increased, so that the turbine wheel and thus the

Compressor can be driven particularly well. This is a desired provided by the compressor boost pressure in a particularly short time to avoid the so-called turbo lag available. In addition, this prevents it at the point of introduction to icing, especially at low temperatures comes, which could adjust with a content of the storage device with ambient temperature and cold internal combustion engine.

The reheating device preferably comprises a heat exchanger, by means of which the additional air can be heated to the additional air as a result of heat transfer from the exhaust gas of the internal combustion engine. As a result, an energy recuperation of that contained in the exhaust and otherwise discharged unused to the environment

Heat energy shown what the efficiency of the supercharger and the internal combustion engine benefits. For heating the additional air thus no additional energy consuming and costly and heating elements are provided, which keeps the energy consumption of the charging device low. This is accompanied by low fuel consumption and low CCVE emissions of

Internal combustion engine.

If a Laval nozzle is provided at the point of introduction, via which the turbine wheel can be acted upon by the additional air, then the turbine wheel can be acted upon by the additional air in a particularly efficient and streamlined manner and can therefore be driven.

In a further embodiment of the invention, the turbine housing has at least two floods which are fluidly separated from each other at least in regions by means of a partition wall of the turbine housing. In other words, the turbine housing is formed at least twice. For at least partially fluidic separation of the floods, the partition wall of the turbine housing is provided, wherein in this partition a fluidically connected to the inlet and by the additional air flow-through inlet channel is formed, via which the turbine wheel with the additional air can be acted upon. This supply of additional air via the inlet channel not only means a particularly streamlined supply of additional air to the turbine wheel. In addition, this has the turbine housing and thus the entire charging only a very small space requirement, which contributes to the avoidance and solution of package problems, especially in a space-critical area such as an engine compartment of the motor vehicle.

Likewise it can be provided that the additional air into one of the floods of the

Turbine housing supplied, in particular blown, is. As a result, the manufacturing costs for the turbine housing can be kept low. In the flood, in which the additional air is optionally injected, it is a so-called lambda flood, which in particular during operation of the Charger fulfills the task of providing a desired air-fuel ratio of the internal combustion engine. The other of the floods is, for example, a so-called EGR flood (EGR exhaust gas recirculation), which at least essentially fulfills the task of providing an advantageous upflow behavior of the turbine, so that an advantageous and desired large amount of exhaust gas from the exhaust gas tract can be returned to the intake of the internal combustion engine and introduced into this. This is by the

Internal combustion engine sucked and supplied to this air with exhaust gas to keep particulate nitrogen oxide emissions low.

The floods of the turbine housing may be symmetrical to each other and have at least substantially equal flow cross-sections. In particular, in the case of the subdivision of the floods in the lambda flood and in the EGR flood, however, it is advantageous if the floods are formed asymmetrically to each other, wherein the lambda flood, for example, has a flow cross-section which is greater than a flow cross section of EGR flow. As a result of the smaller EGR flow in its flow cross-section, a high backflow behavior of the turbine is thus represented, so that a particularly large amount of exhaust gas can be returned from the exhaust gas tract to the intake tract and introduced into it.

In a further embodiment of the invention, an introduction channel which is fluidically connected to the introduction point and can be flowed through by the additional air is provided, which curved in the circumferential direction of the turbine wheel, kinked, bent and / or otherwise curved or oblique and at the discharge point, in particular directly, subsequent Mouth region has, via which the inlet channel opens into a receiving space of the turbine housing in which the turbine wheel is accommodated. This mouth region allows the additional air to be fed obliquely to the turbine wheel in the circumferential direction of the turbine wheel over its circumference, so that the flow of additional air in the circumferential direction of the turbine wheel is already pre-aligned and the turbine wheel does not flow perpendicular to its axis of rotation. In particular, the additional air for flowing into the receiving space in the circumferential direction of the turbine wheel is deflected in its direction of rotation, so that the additional air can flow the turbine wheel particularly streamlined. This leads to a particularly speed and thus boost pressure buildup of the exhaust gas turbocharger.

By means of the charging device, it is in particular possible to design internal combustion engines with regard to the downsizing principle. This means that by means of charging device according to the invention also in internal combustion engines with a relatively small displacement high torques and high performance can be realized while implementing the advantageous instationary behavior.

The charging device according to the invention may also comprise at least two exhaust gas turbochargers with a respective turbine arranged in the exhaust tract of the internal combustion engine, which exhaust gas of the internal combustion engine can be flowed through and arranged in series with one another. This means that the exhaust gas flows through first a first of the turbines and then the second of the turbines. Before flowing through the first turbine, the exhaust gas has a certain pressure level. The exhaust gas is expanded by the first turbine and in particular by the turbine wheel of the first turbine and thus lowered to a contrast lower pressure level.

Subsequently, the exhaust gas flows through the second turbine, through which, in particular by the turbine wheel of the second turbine, the exhaust gas in turn expands and is lowered to a contrast lower pressure level. Since the exhaust gas before flowing through the first turbine is at a higher pressure level than before flowing through the second turbine, the first turbine as a high-pressure turbine and thus the exhaust gas turbocharger comprising this high-pressure turbine is called a high-pressure exhaust gas turbocharger, while the second turbine as a low-pressure turbine and accordingly the exhaust gas turbocharger comprising this low-pressure turbine can be referred to as a low-pressure exhaust gas turbocharger.

As a result, a two-stage charge of the internal combustion engine is shown, by means of which the internal combustion engine is particularly efficient and

can be charged at low efficiency. In this charging device, it is advantageous, the additional air upstream of the turbine wheel of the low-pressure turbine in the

Introduce exhaust tract and in particular introduce upstream of the turbine wheel of the low-pressure turbine in a turbine housing of this low-pressure turbine, in particular to blow. This is advantageous because the low-pressure turbine is disadvantaged in transient operation due to its dimensions relative to the high-pressure turbine.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features mentioned above in the description and

Feature combinations and the below in the description of the figures mentioned and / or in the figures alone features and feature combinations are not only in the specified combination, but also in others

Combinations or in isolation usable without departing from the scope of the invention.

The drawing shows in:

Fig. 1 is a schematic diagram of an internal combustion engine with a

Charging device, which comprises an exhaust gas turbocharger, the additional means for driving the exhaust gas turbocharger can be fed by means of a feeding device of the charging device;

Fig. 2 is a schematic diagram of another embodiment of the

Internal combustion engine with the charging device according to FIG. 1;

Fig. 3 is a schematic longitudinal sectional view of an exhaust gas turbocharger for a

Charging device according to Figures 1 and 2.

4 shows a detail of a schematic longitudinal sectional view of another

Embodiment of the exhaust gas turbocharger according to FIG. 3;

5 shows a detail of a schematic longitudinal sectional view of a turbine of an exhaust gas turbocharger according to FIGS. 3 and 4; and

6 shows a detail of a schematic cross-sectional view of another

Embodiment of the turbine according to FIG. 5.

Fig. 1 shows an internal combustion engine 10 for a motor vehicle with six cylinders 12 and 12 '. During operation of the internal combustion engine 10, this air sucks according to a directional arrow 14 from the environment, the air is under ambient pressure p1. The air flows via a corresponding intake piping of an intake tract 15 of the internal combustion engine 10 to a compressor 16 arranged in the intake manifold 15 of an exhaust gas turbocharger 18 of a charging device 19 of the internal combustion engine 10, wherein the air is compressed by the compressor 16 to a relation to the ambient pressure p1 higher boost pressure. The air heated by the compression flows via a corresponding intake piping of the intake tract 15 to an intercooler 20, through which it flows and by means of which the air is cooled again to increase the degree of turbocharging. Downstream of Charge air cooler 20, the air flows through a corresponding intake piping of the intake tract 15 on to an air intake manifold 22 arranged in the intake manifold 15, by means of which the standing under a pressure p2s air to the cylinders 12 and 12 'is supplied.

The internal combustion engine 10 is, for example, a directly injecting gasoline engine or a directly injecting diesel engine, wherein fuel is injected directly into the cylinders 12 and 12 'by means of a respective injector and thus supplied to the air in the cylinders 12 and 12' , In the internal combustion engine 10 may also be a

Internal combustion engine 10 act with intake manifold injection, wherein the air upstream of the cylinder 12 and 12 ', for example, in the air distributor 22, is supplied with fuel. Thus, a premixed air-fuel mixture flows into the cylinders 12 and 12 '.

In any embodiment, located in the cylinders 12 and 12 ', an air-fuel mixture which is ignited by spark ignition or by auto-ignition and burns. As a result of this combustion, an exhaust gas is produced in the cylinders 12 and 12 ', which flows out of the cylinders 12 and 12' and into a corresponding exhaust gas piping via an exhaust manifold 32 arranged in an exhaust tract 31 of the internal combustion engine 10. In the exhaust tract 31 is a turbine 34 of the

Exhaust gas turbocharger 8 is arranged, which comprises, for example, two asymmetrical to each other formed floods 36 and 36 '. In the floods 36 and 36 ', the exhaust gas is introduced by means of the exhaust piping. About these floods 36 and 36 'is arranged in a receiving space of a turbine housing of the turbine 34

Turbine supplied to the exhaust gas, the turbine wheel through this

Exhaust gas is driven.

The turbine wheel is rotatably connected to a shaft 38 of the exhaust gas turbocharger 18, with which a compressor wheel of the compressor 16 is rotatably connected. So the compressor wheel can be driven via the turbine wheel and compress the air.

As can be seen from Fig. 1, the exhaust gas of the cylinder 12 'by means of

Combustion manifold 32 is summarized and the flood 36 'is supplied by means of the corresponding exhaust piping. The exhaust gas has the pressure p31. The flood 36 'acts as a so-called EGR flood, which has a smaller flow cross-section than the flood 36 acting as a so-called lambda flood. The flood 36' provides Thus, a desired high Aufstauverhalten ready, so that a desired high amount of exhaust gas by means of an exhaust gas recirculation device 24 of the

Internal combustion engine 0 is branched off from the exhaust tract 31 and to the

Intake tract 15 can be recycled and introduced into the intake tract 15. The lambda flood at least substantially fulfills the task of setting a desired ratio of the fuel to the air in the air-fuel mixture. . The exhaust of the flood 36 has the pressure p32

The exhaust gas is supplied via the floods 36 and 36 'to the turbine wheel and expanded by the turbine 34, so that the exhaust gas downstream of the turbine wheel has a lower pressure p4 than the pressures p31 and p32. About a corresponding exhaust piping then the exhaust gas is released to the environment.

For recirculation of the exhaust gas, the exhaust gas recirculation device 24 comprises a

Branch point 28, at which an exhaust gas recirculation line 26 fluidly with the

Exhaust piping is connected. Thus, exhaust gas from the exhaust piping into the

Exhaust gas recirculation line 26 at the branch point 26 and flow over the

Exhaust gas recirculation line 26 are returned to the intake manifold 15. This is the

Exhaust gas recirculation line 26 fluidly connected to the Ansaugverrohrung at a discharge point 30 so that the exhaust gas from the exhaust gas recirculation line 26 can flow into the exhaust pipe. As a result, the compressed air is exposed to exhaust gas, so that particle and nitrogen oxide emissions of the internal combustion engine 10 can be kept low.

The exhaust gas recirculation device 24 comprises an exhaust gas recirculation cooler 40, by means of which the exhaust gas flowing through the exhaust gas recirculation line 26 is to be cooled. Furthermore, the exhaust gas recirculation device 24 comprises an exhaust gas recirculation valve 42, by means of which a

desired recirculating amount of exhaust gas is adjustable.

The charging device 19 comprises an air compressor 44 of a feed device 45 of the charging device 19, which can be driven by the internal combustion engine 10. For this purpose, the air compressor 44 is connected, for example via at least one belt, via at least one chain, via at least one pair of gears or the like connecting element with a crankshaft of the internal combustion engine 10. The air compressor 44 sucks during its operation air from the environment according to a directional arrow 46 and compresses this air. The compressed air flows to a downstream of the

Air compressor arranged tank 48 of the feeding device 45, in which the compressed and thus stored as compressed air is stored. For example, the air in the tank 48 has a pressure in the range of 10 to 12 bar inclusive.

The received in the tank 48 and present as compressed air air is used as additional air to drive the turbine of the turbine 34 of the exhaust gas turbocharger 18 and thus the compressor wheel of the compressor 6 of the exhaust gas turbocharger 18. For this purpose, a connecting line 50 of the feed device 45 is provided, which is fluidically connected on the one hand to the tank 48. On the other hand, it flows at least indirectly into the receiving space in which the turbine wheel of the turbine 34 is received. This means that the additional air can be introduced into the turbine housing and the turbine wheel can be acted upon by this additional air in order to drive it by means of the additional air, in particular in addition to the exhaust gas.

This is particularly advantageous in low load ranges of the internal combustion engine 10, in which optionally there is only a small mass flow of the exhaust gas. This low mass flow of the exhaust gas may not be capable of higher load ranges, in particular the full load range, the

Internal combustion engine 10 designed and possibly a high inertia having turbine wheel to drive in a desired manner, so that it comes to only sluggish speed structure of the compressor wheel at a transition from low load ranges to the contrast higher load ranges. This can lead to an undesirable instationary behavior of the internal combustion engine 10 and to an undesired driving behavior of the same, since with the

unwanted speed buildup is accompanied by an undesirable boost pressure build-up. In other words, it takes an undesirably long time for the

Internal combustion engine can provide a desired by a driver of the motor vehicle torque or a desired performance.

To avoid this unsatisfactory instationary behavior or at least in the

To improve substantially, now the turbine wheel and thus the compressor can be driven by the additional air in particular at a transition from lower to higher load ranges. This possibility of driving the turbine wheel both by means of the exhaust gas and by means of the additional air, even at the transition from low to higher load ranges, a fast speed and thus a faster boost pressure build-up, so that the torque desired by the driver or the desired performance at least almost without delay of the

Internal combustion engine 10 can be provided.

This is the case because the additional driving of the turbine wheel the

Turbine performance increased and run-up, i. An increase in the rotational speed of the turbine, compared to an exclusive driving of the turbine wheel by means of the exhaust gas can be accelerated. The so-called turbo lag is at least in the

Essentially avoided. In addition, a stationary and a non-stationary design of the turbocharger 18 and the internal combustion engine 10 by the

Feeding device 45 is not adversely affected.

In order to introduce the additional air as needed via a discharge point 52 of the feed device 45 in the exhaust system 31 and so to impinge on the turbine as needed with the additional air, the feed device 45 comprises a valve device 54. The valve device 54, for example, only between one

Connecting line 50 releasing release position and the connecting line 50 occlusive closed position adjustable, wherein in the release position, a maximum flow cross-section is released by means of the valve device 54. In the closed position, a minimum flow cross-section, for example a

Flow cross-section of zero, means of the operating device 54 is formed.

It is also possible that the valve device 54 has at least one intermediate position between the release position and the closed position, in which a smaller flow cross-section than in the release position but a larger

Flow cross-section than is formed in the closed position by the valve device 54. Particularly advantageous are several such intermediate position by means of

Valve device 54 adjustable, wherein the intermediate positions differ with respect to the enabled or blocked flow cross-section.

The turbine 34 of the exhaust gas turbocharger 18 is designed for example as a solid geometry turbine. That it does not include any adjusting device for influencing

Flow conditions upstream and / or downstream of the turbine wheel, in particular for variably setting a flow cross-section upstream of the turbine wheel. However, it is possible that the turbine 34 also includes such an adjusting device, by means of which the flow conditions upstream and / or downstream of the turbine wheel can be influenced. Such an adjusting device allows, for example, the

Constricting flow cross-section upstream of the turbine wheel or in contrast to drive the turbines 34 to different operating points of the internal combustion engine.

The advantage of the so-called solid geometry turbine, however, is that it has a low complexity and thus a low number of parts and low costs. Nevertheless, it allows a particularly advantageous transient behavior of the

Internal combustion engine 10, since the turbine wheel can also be driven by means of the additional air.

The turbine 34 includes a bypass 56 having a bypass 58 through which exhaust gas can bypass the turbine. As a result, the turbine wheel is not acted upon by the exhaust gas and not driven by this. The

Bypass device 58 serves to control the boost pressure. to

needs-based control or adjustment of the boost pressure includes the

Bypass device 56 an ambient valve 60, which is also referred to as waste gate.

The charging device 19 with the feeding device 45 also has the advantage that in addition to the thermodynamic advantages by driving the turbine by means of the additional air, the need for flaps, valve means and / or Umblaseöffnungen in or on the side of the intake tract 15 does not exist. Rather, the charging device 19 with the supply device 45 is an uncomplex

Possibility to represent a very good instationary behavior of the internal combustion engine 10 by driving the turbine wheel by means of the additional air.

FIG. 2 shows an alternative embodiment of the internal combustion engine 10 comprising the cylinders 12 and 12 '. As can be seen from Fig. 2, the

Cylinder 12 'summarized and are supplied via the functioning as an EGR flood flood 36' of the turbine 34.

The exhaust gas of the cylinder 12 is also by means of the exhaust manifold 32nd

summarized. The combined exhaust of the cylinder 12 is the as

so-called lambda flood acting flood 36 supplied. The flood 36 serves in

Essentially, a desired air-to-power ratio of

Internal combustion engine 10 and has opposite to the AGR

acting flood 36 'has a larger flow cross-section. The turbine 34 of the exhaust gas turbocharger 18 according to FIG. 2 can also be designed as a double-flow asymmetrical solid geometry turbine with or without a bypass device 56 (waste gate). Likewise, the turbine 34 may be formed as shown in FIG. 2 as an asymmetric Varioturbine and include, for example, an adjusting device 62, by means of which flow conditions upstream of the turbine wheel can be acted upon. The adjusting device 62 is designed for example as a tongue slide and comprises in the circumferential direction of the turbine wheel over its circumference and arranged in

Circumferentially displaceable tongues, by means of which a flow cross-section upstream of the turbine wheel is adjustable. In order to be able to adapt the turbine 34 to different operating points in the characteristic map of the internal combustion engine 10, a control device 64 is provided which controls the adjusting device 62 and the exhaust gas recirculation valve 42.

To clean the exhaust gas before it flows to the environment, includes

Internal combustion engine 10 an exhaust aftertreatment device 66. The

Storage device 66 includes, for example, a particulate filter and / or a

Oxidation catalyst and / or a nitrogen oxide storage catalyst and / or an SCR catalyst (SCR - selective catalytic reduction).

The exhaust gas recirculation device 24 comprises a damping device 68 arranged downstream of the exhaust gas recirculation cooler 40 with a damping volume 70. By means of the damping device 68, pressure pulsations of the recirculated exhaust gas are avoided or at least substantially reduced.

In the intake tract 15, an air filter 72 is arranged, by means of which the intake of the internal combustion engine 10 air is to be filtered. 2, a crankshaft 74 is shown by means of which a translational movement of pistons received in the cylinders 12 and 12 'is to be converted into a rotational movement according to a directional arrow 76.

The feeding device 45 of the charging device 19 comprises two heat exchangers 78 and 78 '. The heat exchangers 78 and 78 'are arranged in the flow direction of the additional air from the tank 48 to the inlet 52 in the exhaust duct 31 and allow heating of the additional air before it flows into the exhaust duct 31 and the

Turbine wheel flows to. For this purpose, the heat exchanger 78 is in operative connection with the

Exhaust after-treatment device 66 and is of the additional air according to a

Directional arrow 80 can be flowed through. As a result, a heat transfer from the exhaust gas aftertreatment device 66, which is hot during operation of the internal combustion engine 10, to the additional air flowing through the heat exchanger 78 is possible, as a result of which it is heated by the additional air.

The heat exchanger 78 'works on the countercurrent principle and is in a

Flow direction of the exhaust gas and in a further direction of flow opposite direction of flow of the additional air flowed through. Of the

Heat exchanger 78 'allows heat transfer from the hot exhaust gas to the additional air, so that heats the additional air. Thereby, a recuperation of heat energy contained in the exhaust gas as well as heat energy of the

Exhaust after-treatment device 66 is shown, which would otherwise be discharged unused to the environment. This contributes to a high efficiency of the internal combustion engine 10 with the charging device 19 at. Furthermore, this results in a further increase in the turbine power of the turbine 34, since the turbine power is proportional to the inlet temperature of an incoming and the turbine wheel

driving gas and thus the additional air is. In addition, icing of the discharge point 52 is thereby avoided.

At this point it should be noted that the overview because of in Fig. 2 on the

Representation of the air compressor 44 and the valve device 54 and any other components of the feed device 45 is omitted.

Fig. 3 shows a possible embodiment of the exhaust gas turbocharger 18 of

Charging device 19 according to FIGS. 1 and 2. The exhaust gas turbocharger 18 includes the compressor 16, which has a compressor housing 82 in which a compressor wheel 84 is rotatably received about a rotation axis 86. The exhaust gas turbocharger 18 further includes a bearing housing 88, in which the shaft 38 is rotatably mounted.

The turbine 34 of the exhaust gas turbocharger 18 includes a turbine housing 90 with the two floods 36 and 36 '. As can be seen from FIG. 3, the floods 36 and 36 'are at least substantially symmetrical to each other and at least in the

Substantially equal flow cross sections. Through the turbine housing 90, a receiving space 92 is formed, in which a turbine wheel 94 of the turbine 34 is rotatably received about the axis of rotation 86. Like the compressor wheel 84, the turbine wheel 94 is non-rotatably connected to the shaft 38.

3, the introduction point 52 is integrated in the turbine housing 90 of the turbine 34, wherein the introduction point 52 is rotated in the circumferential direction and rotational direction of the turbine wheel 94 in the image plane of FIG. 3. At the point of introduction 52, a Laval nozzle 96 connects, via which the additional air upstream of the turbine wheel 94 to flow into the turbine housing 90 and the turbine wheel 94 can flow streamlined to drive. For this purpose, the Laval nozzle 96 opens via the introduction point 52 into an annular nozzle 98 formed by walls of the turbine housing 90, which is arranged upstream of the turbine wheel 94. About the annular nozzle 98, the exhaust gas and optionally the additional air flow to the turbine wheel 94 at least substantially in the radial direction. The turbines 34 of the charging devices 19 according to FIGS. 1 and 2 as well as other embodiments of the charging device 19 may thus be radial turbines.

Depending on an advantageous mass flow of the additional air to be introduced into the exhaust tract 31, in particular einzubasenden, in conjunction with the narrowest flow cross-section, in particular nozzle cross-section, upstream of the turbine wheel 94, a corresponding number of discharge points such as the discharge point 52 and a corresponding number of nozzles such as the Laval Nozzle 96 fixed. In other words, more than one introduction point 52 and / or Laval nozzle 96 can be provided in order to introduce the additional air into the exhaust gas tract 31 for, in particular, additional driving of the turbine wheel 94.

The Laval nozzle 96 represents a swirl nozzle, by means of which the additional air flowing into the exhaust tract 31 or into the turbine housing 90 can be imparted with a swirl. Other swirl generating devices are also possible. Such a twist is a particularly spiral-shaped rotational movement about an axis parallel to the flow direction.

4 shows a further embodiment of the turbine designed as a double-flow symmetrical turbine 34 according to FIG. 3. As shown in FIG. 4, are

Einleitstellen 52 arranged in overlap with an open trained wheel back 100 of the turbine wheel 94 and formed in a heat shield 102 as passages. The heat shield 102 serves that bearing housing 88 in front of a

undesirably high heat input by the hot turbine housing 90 To protect flowing exhaust gas. The passage openings are formed as swirl openings, so that the additional air, the turbine wheel 94 with a high

Flow energy from Radrücken 100 at least substantially initially flow in the axial direction and thus can drive very efficient.

A space 104 at least partially limited by the bearing housing 88, the turbine housing 90 and the heat shield 102 acts as a collecting space, wherein high gas forces must be taken into account when dimensioning and fastening the heat shield 102. The introduction points 52 in the form of the swirl openings are located in very close proximity to the turbine wheel 94 or its wheel back 100, so that an at least substantially direct admission of the turbine wheel 94 by the additional air is made possible. This favors a particularly efficient driving of the

Turbine wheel 94 and thus the compressor wheel 84 to illustrate a fast

Torque and thus boost pressure structure.

5 shows a further embodiment of the double-flow symmetrical turbine 34 according to FIGS. 3 and 4. In conjunction with FIGS. 3 and 4, it can be seen that the turbine housing 90 has a partition wall 106, through which the floods 36 and 36 'At least partially fluidly separated from each other.

In the partition 106 of the turbine 34 according to FIG. 5, an introduction channel 108 is now formed, which adjoins the inlet 52 and is fluidly connected thereto. This makes it possible in a very space-saving manner to introduce the additional air at least substantially in the radial direction of the turbine wheel 90 via the discharge point 52 in the annular nozzle 98, in particular to blow. In other words, an exit of the additional air from the inlet channel 08 advantageously takes place at least almost centrally into the annular nozzle 98 upstream of the turbine wheel 94. This provides a streamlined application and thus an efficient driving of the turbine wheel 94.

FIG. 6 shows a further embodiment of the introduction channel 108. The introduction channel 108 has an opening region 112, via which the introduction channel 108 opens into the ring nozzle 98 or into the receiving space 92. The mouth region 102 in this case adjoins directly at the introduction point 52 and is fluidically connected thereto. 6, the mouth region 112 in the circumferential direction of the turbine wheel 94 of the receiving space 92 and thus the annular nozzle 98 according to a directional arrow 114 in the direction of rotation according to a directional arrow 116, in which the Turbine wheel 94 during operation of the exhaust gas turbocharger 18 rotates, curved. As a result, the additional air is deflected before entering the annular nozzle 98 in the circumferential direction according to the directional arrow 116, which is represented by a directional arrow 110 in FIG. 6. As a result, the additional air flows the turbine wheel 94 obliquely to its real direction, whereby the turbine wheel is particularly streamlined and efficiently driven.

Claims

claims

1. charging device (19) for an internal combustion engine (10) of a

Motor vehicle, comprising at least one exhaust gas turbocharger (18) which comprises a turbine housing (90) arranged in an exhaust tract (31) of the internal combustion engine (10) and permeable by exhaust gas of the internal combustion engine (10) in which a turbine wheel (94) can be acted upon by the exhaust gas. is rotatably received, and with at least one feed device (45) by means of which the exhaust gas turbocharger (18) additional air can be supplied,

characterized in that

the feed device (45) has at least one introduction point (52) arranged in the exhaust gas tract (31), via which the turbine wheel (94) can be acted upon by the additional air.

2. charging device (19) according to claim 1,

characterized in that

the introduction point (52) is arranged at least in regions upstream of the turbine wheel (52).

3. charging device (19) according to one of claims 1 or 2,

characterized in that

the turbine wheel (94) by means of the feed device (45) can be acted upon with compressed air as the additional air.

4. charging device (19) according to one of the preceding claims,

characterized in that the feed device (45) comprises a swirl device (96) by means of which the additional air which acts on the turbine wheel (94) is to be provided with a swirl.

Charging device (19) according to one of the preceding claims,

characterized in that

the discharge point (52) at least partially at the height of a largest

Diameter of the turbine wheel (94) is arranged.

Charging device (19) according to one of the preceding claims,

characterized in that

at least one heating device (78, 78 ') is provided, by means of which the additional air can be heated upstream of the turbine wheel (94).

Charging device (19) according to claim 6,

characterized in that

the heating device (78, 78 ') comprises at least one heat exchanger (78, 78') by means of which the additional air can be heated to the additional air as a result of heat transfer from exhaust gas of the internal combustion engine (10).

Charging device (19) according to one of the preceding claims,

characterized in that

at the inlet point (52) a Laval nozzle (96) is provided, via which the turbine wheel (94) can be acted upon by the additional air.

Charging device (19) according to one of the preceding claims,

characterized in that

the turbine housing (90) at least two by means of a partition (106) of the turbine housing (90) at least partially fluidly separated from each other floods (36, 36 '), wherein in the partition wall (106) with the inlet (52) fluidly connected and of the additional air flow-through inlet channel (108) is formed, via which the turbine wheel (94) can be acted upon by the additional air.

10. charging device (19) according to one of the preceding claims,

characterized in that

a lead-in channel (108), which is fluidically connected to the inlet point (52) and can be flowed through by the additional air, is provided, which has an inlet channel (108)

Circumferential direction (1164) of the turbine wheel (94) curved and / or kinked and / or curved and at the discharge point (52), in particular directly, subsequent mouth region (112), via which the inlet channel (108) at least indirectly in a receiving space ( 92) of the turbine housing (90) for receiving the turbine wheel (94) opens.