DE102015003296A1 - Exhaust gas turbocharger for an internal combustion engine and method for operating such an exhaust gas turbocharger - Google Patents

Abstract

The invention relates to an exhaust gas turbocharger (10) for an internal combustion engine (10), in particular of a motor vehicle, with at least one housing element (30) and with at least one conduit element (32) via which a lubricant can be supplied to the housing element (30), at least one Detection element for detecting at least one of an operation of the exhaust gas turbocharger (20) characterizing value and at least one valve element (66) are provided, by means of which the conduit element (32) is fluidically locked in dependence on the value, and a method for operating such an exhaust gas turbocharger (20 ).

Description

The invention relates to an exhaust gas turbocharger according to the preamble of patent claim 1 and to a method for operating such an exhaust gas turbocharger.

The charging of internal combustion engines has now been almost fully enforced in both commercial vehicle and passenger car application. As part of such a charge, the respective internal combustion engine is supplied by means of at least one exhaust gas turbocharger with compressed air. For this purpose, the exhaust gas turbocharger comprises a turbine, which can be driven by exhaust gas of the associated internal combustion engine. With the turbine, a compressor is coupled, which is drivable via the turbine and thus of the exhaust gas. By means of the compressor, the air supplied to the internal combustion engine is compressed.

The exhaust gas turbocharger comprises a rotor, which is usually referred to as a rotor. Such a rotor comprises a turbine wheel which can be driven by the exhaust gas and thereby driven, a shaft which is non-rotatably coupled to the turbine wheel and a compressor wheel which is non-rotatably coupled to the shaft for compressing the air. The rotor is rotatably supported by the shaft on a housing element, in particular a bearing housing, of the turbocharger about an axis of rotation relative to the bearing housing. Depending on the stroke volume of the engine designed as a reciprocating internal combustion engine such rotors have speeds between 100,000 and 300,000 revolutions per minute or even higher speeds with maximum peripheral speeds of outer blade areas between 500 and 600 meters per second. From these speeds in circumferential speeds result in high loads of the running gear, in particular the turbine wheels and the compressor wheels. Therefore, there are in principle the highest requirements with regard to the granting of security against safety-relevant high rotational energies.

Such an exhaust gas turbocharger also comprises at least one line element. In this case, the line element can be flowed through by a lubricant, in particular lubricating oil, so that the lubricant can be supplied to the housing element via the line element. The lubricant is used for example for lubricating at least one bearing, via which the rotor is mounted on the bearing housing or on the housing element. In other words, the housing element may be the bearing housing.

If, however, there is a failure, for example, to rupture of such a rotor, housing elements in which the respective rotors are received are preferably configured such that they restrain rotor fragments formed as a result of the failure or at least slow them down with respect to their speed, so that the environment of the rotor respective exhaust gas turbocharger is protected.

The US 20111/0083433 A1 discloses an explosion protection for a gas turbine, in particular an exhaust gas turbocharger, wherein the explosion protection has a structure with a plurality of layers, which surrounds the actual turbine housing at least partially and in particular in the radial direction.

Furthermore, the EP 2 216 516 A1 to take a compressor of an exhaust gas turbocharger as known. The compressor comprises a compressor wheel rotatable about an axis, an outer compressor housing and a housing insert arranged radially outside the compressor wheel. The housing insert comprises an insert wall contour which, together with a hub of the compressor wheel, delimits a flow channel. In this case, it is provided that the housing insert rests against an axial stop of the outer compressor housing directed towards the compressor wheel, wherein a bending element is provided for transmitting axial forces from the insert wall contour to the outer compressor housing. The bending element comprises at least two axially aligned webs arranged offset from one another and a support element connecting the webs to one another. The support element is aligned perpendicular to the axial direction and arranged with respect to the axial direction between the webs.

Another mechanical safety device is from the DE 10 2008 022 693 A1 known. This discloses an exhaust gas turbocharger for an internal combustion engine, with a flow-through housing and a rotatably mounted in the housing rotor, wherein the rotor comprises a turbine wheel with a hub face and a non-rotatably connected by means of a compressor wheel. The turbine is drivable in the operation of exhaust gas of the internal combustion engine. It is envisaged that an impact body is positioned in the housing in the region of the hub end face while maintaining a distance. By means of the impact body, it is possible to limit the axial movement of the turbine wheel in case of damage. Thus, in the event of damage to the exhaust gas turbocharger a total uselessness of the same can be avoided.

Object of the present invention is to provide an exhaust gas turbocharger of the type mentioned above and a method for operating such an exhaust gas turbocharger, by means of which a particularly safe operation of the exhaust gas turbocharger can be realized.

This object is achieved by an exhaust gas turbocharger having the features of patent claim 1 and by a method for operating such an exhaust gas turbocharger having the features of patent claim 6. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to provide an exhaust gas turbocharger specified in the preamble of claim 1 species, by means of which a particularly safe operation can be realized according to the invention at least one detection element for detecting at least one operation of the exhaust gas turbocharger characterizing value and at least one valve element is provided, wherein the conduit member by means of the valve element is fluidic lockable depending on the value.

The invention is based on the idea that lubricant may escape if a running gear of the exhaust gas turbocharger fails if no corresponding countermeasures are taken. Such a lubricant outlet results, for example, from the fact that a shaft of the power tool breaks and / or at least one impeller of the power tool bursts, whereby at least one so-called shaft bore is opened. In such a shaft bore is a trained example as a through hole bearing receptacle of a bearing housing, in particular of the housing element, the exhaust gas turbocharger, in which bearing support the lubricant is promoted in a normal operation of the exhaust gas turbocharger to cool the running gear. Namely, the power tool is usually received in this bearing receptacle and mounted on this bearing housing or on the housing element. Since the lubricant is usually further promoted by a pump, in particular an oil pump even in such a failure of the rotor and when opening the shaft bore, not inconsiderable amounts of lubricant could escape uncontrollably.

However, since an undesired operating state of the exhaust-gas turbocharger, in particular a failure of at least one component, in particular of the running gear, of the exhaust-gas turbocharger is detected by means of the detection element and the line element is fluidly blocked as a result of this detection, the amount of lubricant exiting from the exhaust-gas turbocharger can be kept particularly low or even leakage of lubricant can be prevented. As a result, it can also be prevented that the lubricant can come into contact with hot walls of the internal combustion engine and thereby optionally be ignited, which is critical in particular in a gasoline engine with very high exhaust gas temperatures. Furthermore, this can prevent excessive smoke and smoke pollution of the environment.

Further, it can be prevented that an excessive amount of lubricant sucked by the internal combustion engine and their intake tract and further example, in a charge air cooler, resulting in a water hammer would result as a result of a compressor-side, increased lubricant entry into the intake system. However, this risk can be kept low at least.

The invention also includes a method for operating an exhaust gas turbocharger for an internal combustion engine, in particular a motor vehicle, wherein the exhaust gas turbocharger comprises at least one housing element and at least one line element. Via the line element, a lubricant can be supplied to the housing. In the context of the method according to the invention, it is provided that at least one value characterizing an operation of the exhaust gas turbocharger is detected by means of at least one detection element. Furthermore, it is provided that by means of at least one valve element, the line element is fluidly blocked in dependence on the value. Advantageous embodiments of the exhaust gas turbocharger according to the invention are to be regarded as advantageous embodiments of the method according to the invention and vice versa. In the course of the method according to the invention, a damage event of the exhaust gas turbocharger, in particular of its rotor tool or rotor, can be detected at least substantially directly. In direct consequence, the lubricant supply to the housing element, in particular to a bearing housing of the exhaust gas turbocharger, can be prevented. The lubricant outlet can thus be avoided.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the figure description and / or alone in the single figure can be used not only in the respectively indicated combination but also in other combinations or alone, without the frame to leave the invention.

The drawing shows in the single FIGURE is a schematic representation of an internal combustion engine for a motor vehicle, with an exhaust gas turbocharger, which at least one housing element and a conduit element, via which a lubricant can be supplied to the housing element, at least one detection element being provided for detecting at least one value characterizing an operation of the exhaust gas turbocharger and at least one valve element, by means of which the conduit element can be fluidically blocked as a function of the value.

The figure shows a whole with 10 designated internal combustion engine, which has, for example six not shown in the figure, combustion chambers in the form of cylinders. The internal combustion engine 10 serves for driving a motor vehicle and is designed as a reciprocating internal combustion engine, wherein in the cylinders in each case a piston is received translationally movable relative to the respective cylinder. The respective piston is articulated via an associated connecting rod with a crankshaft 12 the internal combustion engine 10 coupled. The crankshaft 12 is an output shaft, over that of the internal combustion engine 10 provided torques are dissipated.

By three first of the six cylinders a so-called AGR group is formed. Exhaust gas of the first cylinder of the EGR group is used in particular to provide particularly high exhaust gas recirculation quantities in the context of exhaust gas recirculation (EGR). As part of the exhaust gas recirculation is exhaust gas from an exhaust tract 14 the internal combustion engine 10 to an intake tract 16 returned and in the intake 16 initiated. As a result, the nitrogen oxide (NO _x ) emissions can be kept low.

The other three of the six cylinders, which are referred to as second cylinders, form a so-called λ group whose exhaust gas is used in particular to set a ratio of air to fuel in the cylinder to a desired value, this ratio as the combustion air ratio (λ ) referred to as. For this purpose, the exhaust gas of the λ group is used in particular to one in the exhaust system 14 arranged turbine wheel 17 a turbine 18 an exhaust gas turbocharger 20 the internal combustion engine 10 drive.

The turbocharger 20 includes a running tool, which also acts as a rotor 22 is designated, wherein the rotor 22 the turbine wheel 17 , one in the intake tract 16 arranged compressor wheel 24 a compressor 26 the exhaust gas turbocharger 20 as well as a wave 28 includes. The turbine wheel 17 and the compressor wheel 24 Both are rotatable with the shaft 28 coupled so that the compressor wheel 24 over the wave 28 from the turbine wheel 17 can be driven. The turbine wheel 17 is driven by the exhaust gas from the cylinders.

The turbocharger 20 further comprises at least one housing element in the form of a bearing housing 30 to which the rotor 22 for example via at least two bearings about an axis of rotation relative to the bearing housing 30 is rotatably mounted. As a further housing elements of the exhaust gas turbocharger 20 a turbine housing, not shown in the figure, and a compressor housing, not shown in FIG. Include. Turbine housing of the turbine 18 is the turbine wheel 17 taken, wherein in the compressor housing of the compressor 26 the compressor wheel 24 is included.

The turbocharger 20 also includes at least one conduit element 32 , The pipe element 32 is on the one hand with a pump 34 the internal combustion engine 10 coupled. The pump 34 serves to convey a lubricant in the form of oil and is thus designed as an oil pump. On the other hand, the line element 32 fluidic with the bearing housing 30 connected. This means that the conduit element 32 for example, with at least one in the bearing housing 30 extending oil guide channel is fluidly connected. This by means of the pump 34 Promoted oil can be the conduit element 32 flow through and thereby over the conduit element 32 be guided to the bearing housing. In other words, the oil is by means of the conduit element 32 the bearing housing 30 supply.

By means of the oil guide channel in the bearing housing 30 the oil is guided to respective bearings, where the rotor 22 via the respective bearings on the bearing housing 30 is stored. This is shown in the figure by a dashed double arrow 36 illustrated. The wave 28 is at the bearings in each, formed as through holes receptacles of the bearing housing 30 recorded, these bearing mounts are also referred to as shaft holes.

As with the dashed double arrow 36 It can be seen is one of the bearing point on the side of the compressor 26 arranged, with the other bearing point on the turbine side 18 is arranged. The oil serves to lubricate and / or cool the bearings and / or the rotor 22 because the rotor 22 rotates at very high speeds of up to 300,000 revolutions per minute or more relative to the bearing housing.

The exhaust tract 14 includes a first exhaust manifold 38 , which is assigned to the EGR group and which serves to merge the exhaust gas from the first cylinders. The exhaust tract 14 also includes a second exhaust manifold 40 , which is assigned to the λ group and serves to merge the exhaust gas of the second cylinder. The exhaust gas from the second cylinders is by means of the exhaust manifold 40 to a exhaust piping 42 the exhaust tract 14 guided, wherein the exhaust gas by means of the exhaust piping 42 is guided to the turbine wheel. This allows the exhaust gas from the second cylinder to drive the turbine wheel.

By means of the exhaust manifold 38 the exhaust gas from the EGR group becomes an exhaust piping 44 the exhaust tract 14 guided, with the exhaust gas through the exhaust piping 44 also to the turbine wheel 17 can be performed.

As can be seen from the figure, the turbine is 18 For example, this is a double-flow design and includes a first tide 46 , which fluidly with the exhaust piping 42 connected is. The turbine 18 also includes a second flood 48 , which fluidly with the exhaust piping 44 connected is. Preferably, it is provided that the flood formed as an EGR flood 48 has a lower effective flow area than the tide 46 , so that thereby a very high backwater behavior is feasible. As a result, particularly high amounts of exhaust gas recirculation (EGR quantities) can be represented.

The internal combustion engine 10 further includes an exhaust gas recirculation device 50 with an exhaust gas recirculation line 52 , The exhaust gas recirculation line 52 is at a branch point 55 with the exhaust piping 44 and to a mixing point M with the intake tract 16 fluidly connected. This allows exhaust gas at the branch point 55 from the exhaust piping 44 branched off and to the intake 16 be recirculated, wherein the recirculated or recirculated exhaust gas at the mixing point M in the intake 16 can be initiated. At the mixing point M, the recirculated exhaust gas with the intake tract 16 mixing air flowing through.

The exhaust gas recirculation device 50 includes an exhaust gas recirculation cooler 54 , which in the exhaust gas recirculation line 52 is arranged and used for cooling the recirculating exhaust gas. In addition, the exhaust gas recirculation device comprises 50 a valve element in the form of a flap 56 , By means of which the amount of recirculated exhaust gas is adjustable.

In the intake tract 16 is upstream of the compressor wheel 24 an air filter 58 arranged, by means of which to be compressed and by the internal combustion engine 10 sucked air is filtered. Downstream of the compressor wheel 24 is in the intake tract 16 a charge air cooler 60 arranged. By means of the intercooler 60 is the means of the compressor wheel 24 compressed and thus heated air cooled. Downstream of the intercooler 60 is a throttle 62 arranged, by means of which a backwater or backflow behavior of the intake 16 for this intake 16 flowing air is adjustable. This allows a pressure gradient between the intake 16 and the exhaust piping 44 be adjusted as needed, so that thereby the amount of recirculating exhaust gas can be adjusted.

The internal combustion engine 10 also includes a control device 64 for controlling or preferably regulating components of the internal combustion engine 10 , The control device 64 also serves to detect the operation of the internal combustion engine 10 characterizing values or signals, these values or signals of the control device 64 is supplied. This is shown in the figure by dashed arrows, which on the control device 64 to get lost. The through the control device 64 effected control of components is illustrated in the Fig. By dashed arrows, the direction of the control device 64 away and onto the respective components to be controlled. This means that by means of the control device 64 the flap 56 and the throttle 62 be regulated or adjusted.

The turbocharger 20 Also includes a valve member, here in the form of a solenoid valve 66 which is in the conduit element 32 is arranged and by means of the control device 64 is regulated or discontinued. The solenoid valve 66 is between a line element 32 fluidly occluding closed position and at least one of the conduit element 32 fluidically released open position adjustable.

Downstream of the mixing point M and upstream of the cylinder, the compressed air has a charge pressure p2s, which is detected by means of a corresponding detection element, in particular a pressure sensor, to the control device 64 transmitted and by the regulatory body 64 Will be received. The speed of the rotor 22 is denoted by n_ATL, which detects by means of a corresponding detection element, for example a speed sensor, to the control device 64 transmitted and received by the latter.

Downstream of the turbine wheel 17 is in the exhaust tract 14 also at least one exhaust aftertreatment device 68 arranged, by means of which the exhaust gas is treated. By means of at least one detection element at least one of the exhaust gas upstream of the exhaust gas aftertreatment device 68 and downstream of the turbine wheel 17 Characterizing signal AS detected, to the control device 64 transmitted and received by this. Alternatively or additionally, at least one further value or a further signal S can be detected, to the control device 64 be transmitted and received by the latter, wherein the signal S, the operation of the Internal combustion engine 10 , in particular the operation of the exhaust gas turbocharger 20 , characterized. The signal AS, the rotational speed n_ATL and the boost pressure p2s are also values or signals which signal the operation of the exhaust gas turbocharger 20 characterize.

These signals are permanently detected or controlled in their time sequence during the operation of the motor vehicle. In particular, respective first time derivatives of said signals are detected and controlled.

If, for example, an abnormality in the time course of the boost pressure p2s and / or in at least one course of the other signals with respect to the instantaneous load of the internal combustion engine 10 recorded, so it can be a malfunction or even a failure of the exhaust gas turbocharger 20 , in particular its rotor 22 be inferred. Such an abnormality is, for example, a sudden collapse of the boost pressure p2s relative to the ambient pressure. Such an abnormality is detected, for example, such that the time profile and / or its first time derivative exceeds or falls below a predefinable threshold value.

As a result, the initially opened solenoid valve 66 by means of the control device 64 adjusted to the closed position. For this purpose, a drive signal VS from the control device 64 to the solenoid valve 66 transferred and from the solenoid valve 66 receive.

This will prevent the oil in case of breakage of the shaft 28 and a resulting release of the shaft bores exhaust gas or turbine side as well as air or compressor side in turbines and compressor side piping of the exhaust tract 14 and / or the intake tract 16 can be pumped. In the flow direction of the oil through the conduit element 32 downstream of the pump 34 and upstream of the solenoid valve functioning as a shut-off valve and a safety valve 66 is a pressure relief valve 70 arranged. Will the conduit element 32 downstream of the pressure relief valve 70 by means of the solenoid valve 66 fluidly blocks and pumps the pump 34 however, oil continues through the conduit element 32 to the solenoid valve 66 , so when exceeding a predetermined threshold value by a pressure of the line element 32 absorbed oil the pressure relief valve 70 open, leaving the oil from the conduit element 32 over the pressure relief valve 70 emerge and flow, for example, in a crankcase and can be funded by the pump. Preferably, it is provided that the solenoid valve 66 in a de-energized state, the closed position occupies. Starts the driver of the motor vehicle, for example, by causing an ignition signal, the internal combustion engine 10 , thereby starting the internal combustion engine 10 is initiated, this leads to the adjustment of the solenoid valve 66 from the closed position to the open position, what with an oil release for the turbocharger 20 accompanied.

In particular, in this regard, it makes sense upstream of the solenoid valve 66 a collection chamber 72 to arrange, which preferably geodetically above the exhaust gas turbocharger 20 is arranged. In other words, the collection chamber 72 in the vertical direction of the motor vehicle above the exhaust gas turbocharger 20 arranged. Through the collection chamber 72 an oil depot is created because oil is closed when the solenoid valve 66 in the collection chamber 72 can collect. Will the internal combustion engine 10 started and thus opens the acting as a safety valve solenoid valve 66 . 50 can through the collection chamber 72 and the oil reservoir formed there directly the lubrication of the exhaust gas turbocharger 20 take place, as sufficient oil by means of gravity support from the collection chamber 72 to the exhaust gas turbocharger 20 can flow. This represents a favoring of sufficient lubrication of the exhaust gas turbocharger 20 during a start-up phase, so that the risk of wear damage due to insufficient start-up lubrication can be kept particularly low.

The turbine wheel 17 has an end face 74 on, which is also referred to as hub front side. The front side 74 is in the axial direction of the rotor 22 the compressor wheel 24 away. Preferably, it is provided that in the turbine housing a fixed impact body is fixed relative to the turbine housing, which in the axial direction from the end face 74 is spaced. In other words, in the area of the front side 74 while maintaining a distance, an impact body is positioned in the turbine housing. Here is the front page 74 in the axial direction to the outside at least partially covered by the baffle. By means of the impact body, it is possible in case of damage, an axial movement of the turbine wheel 17 to limit, since the turbine wheel 17 in a damage-related movement in the axial direction outwards over its front side 74 in support system can come with the baffle body after the turbine wheel 17 has overcome the said distance. As a result, damage, in particular consequential damage can be mitigated.

LIST OF REFERENCE NUMBERS

10

Internal combustion engine

12

crankshaft

14

exhaust tract

16

intake system

17

turbine

18

turbine

20

turbocharger

22

rotor

24

compressor

26

compressor

28

wave

30

bearing housing

32

line element

34

pump

36

double arrow

38

exhaust manifold

40

exhaust manifold

42

exhaust piping

44

exhaust piping

46

flood

48

flood

50

Exhaust gas recirculation device

52

Exhaust gas recirculation line

54

Exhaust gas recirculation cooler

55

branching point

56

flap

58

air filter

60

Intercooler

62

throttle

64

control device

66

magnetic valve

68

exhaust treatment device

70

Pressure relief valve

72

plenum

74

face

AS

signal

S

signal

VS

control signal

n_ATL

rotation speed

p2s

boost pressure

M

mixing point

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

• US 2011/0083433 A1 [0006]
• EP 2216516 A1 [0007]
• DE 102008022693 A1 [0008]

Claims (6)

Exhaust gas turbocharger ( 10 ) for an internal combustion engine ( 10 ), in particular a motor vehicle, with at least one housing element ( 30 ) and with at least one line element ( 32 ) over which the housing element ( 30 ) a lubricant can be supplied, characterized in that at least one detection element for detecting at least one operation of the exhaust gas turbocharger ( 20 ) characterizing value and at least one valve element ( 66 ) are provided, by means of which the line element ( 32 ) is fluidically lockable depending on the value. Exhaust gas turbocharger ( 20 ) according to claim 1, characterized in that the valve element ( 66 ) as a solenoid valve ( 66 ) is trained. Exhaust gas turbocharger ( 20 ) according to one of claims 1 or 2, characterized in that upstream of the valve element ( 66 ) and downstream of a pump ( 34 ) for conveying the lubricant, a collection chamber ( 72 ) in the conduit element ( 32 ) is provided, which opposite to a respective, on both sides of the collection chamber ( 72 ) subsequent region of the line element ( 32 ) has a larger cross-section. Exhaust gas turbocharger ( 20 ) according to one of the preceding claims, characterized in that the housing element ( 30 ) as a bearing housing ( 30 ) is formed, on which a running tool ( 22 ) of the exhaust gas turbocharger ( 20 ) is stored. Exhaust gas turbocharger ( 20 ) according to one of the preceding claims, characterized in that the exhaust gas turbocharger ( 20 ) at least one rotatable about an axis of rotation and an end face ( 74 ) having impeller ( 17 . 24 ), in particular turbine wheel ( 17 ), wherein in the region of the end face ( 74 ) while maintaining a distance from the end face ( 74 ) An impact body is arranged. Method for operating an exhaust gas turbocharger ( 20 ) for an internal combustion engine ( 10 ), which at least one housing element ( 30 ) and at least one line element ( 32 ), over which the housing element ( 30 ) a lubricant can be supplied, wherein by means of at least one detection element at least one operation of the exhaust gas turbocharger ( 20 ) characterizing value is detected and wherein by means of at least one valve element ( 66 ) the conduit element ( 32 ) is fluidly blocked as a function of the value.

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