DE102006015253A1 - IC Engine has exhaust gas turbines connected by by-pass with relief valve in downstream turbine casing which has chamber connected to turbine by channel adjusted by slide with rib fitting into groove in partition wall when valve is closed - Google Patents

Abstract

The invention relates to an internal combustion engine (10) with two exhaust gas turbines (16, 26, 54) connected in series in an exhaust line (18), wherein the exhaust line (18) has an outlet of the exhaust gas engine (16) close to the engine with an exhaust gas flow (64) in the exhaust gas remote engine exhaust gas turbine (26, 54) and the engine-near exhaust gas turbine (16) has a bridging bypass (46), wherein in the bypass (46) a blow-off valve (48) is positioned, which in a turbine housing (62) of the engine exhaust gas turbine (26, 54) is integrated, wherein the blow-off valve (48) has a collecting space (72), in which the bypass (46) einmündelt and via an orifice cross-section (74) with a turbine wheel (66) of the engine exhaust gas turbine remote (26, 54) in combination stands, wherein in the mouth cross section (74) an adjustable die (78) is arranged and the collecting space (72) and the mouth cross-section (74) from the exhaust gas flow (64) by a partition wall (76) is separated.
According to the invention, the dividing wall (76) and / or the die (78) at least one recess (88) and the die (78) and / or the partition wall (76) at least one projection (90), wherein the projection (90) in Shape, size and / or position to the recess (88) is formed corresponding, wherein the recess (88) and the projection (90) in the closed position of the die (78) form a positive connection for closing the mouth cross-section (74).

Description

The The invention relates to an internal combustion engine with two in a row switched turbines in the exhaust system according to the preamble of the claim 1.

to Compliance with the statutory emission limit values are becoming ever higher exhaust gas recirculation rates required. This increase in EGR rates means for the supercharger the internal combustion engine, a demand for higher boost pressures not too big Reductions in the specific performance of internal combustion engines to have to accept. To achieve such higher boost pressures is especially in commercial vehicles, but also already in passenger cars the concept of multi-stage charging systems known.

An internal combustion engine with two turbochargers connected in series is, for example, in DE 101 44 663 A1 disclosed. The internal combustion engine is equipped with two turbochargers connected in series, of which the close-coupled supercharger is designed as a high-pressure stage and the supercharger remote from the engine as a low-pressure stage. The compressors of both exhaust gas turbochargers are connected in series in the intake tract, as well as the exhaust gas turbines both superchargers in the exhaust system are arranged one behind the other. To ensure that the high-pressure turbine near the engine in the upper speed and load range of the internal combustion engine is not overloaded and thereby destroyed, a bypass is provided, which bridges the high-pressure turbine and opens in the exhaust pipe between high-pressure and low-pressure turbine. In this bypass there is an adjustable blow-off valve, which is set in dependence on state and operating variables of the internal combustion engine, in particular the exhaust back pressure upstream of the high-pressure turbine close to the engine. Another bypass is provided to bypass the engine remote turbine; Also in this bypass is an adjustable blow-off valve. With the help of the relief valves in the two bypass lines a situation-appropriate blow-off can be performed around one or both exhaust gas turbines around.

In The applicant has a further development of this technology Internal combustion engine with two turbochargers connected in series, the in each case an exhaust gas turbine in the exhaust line and a compressor in Include intake, developed with a close-coupled exhaust gas turbine Bypass with a blow-off valve, wherein the blow-off valve in the turbine housing of engine-removed exhaust gas turbine is integrated and a collecting space in the the bypass opens and which is in communication with the turbine wheel, and an adjustable die in the mouth section the collecting space to the turbine wheel has.

at On the one hand, such an internal combustion engine can be overloaded the engine near exhaust gas turbine can be avoided by the bypass and On the other hand exergy losses due to the bypass of the engine near Minimized exhaust gas and the overall efficiency can be improved can, by exergy the blow-off quantity when bypassing the high-pressure turbine converted into speed energy directly in front of the low-pressure turbine wheel and this speed energy then immediately in the following Low-pressure turbine wheel is converted into mechanical work.

outgoing From this prior art, the invention is based on the object a secure sealing of the blow-off valve in the closed position to ensure the die. Such a sealing construction should also with simple constructive activities will be realized.

These Task is by an internal combustion engine with two consecutively switched exhaust gas turbine solved with the features of claim 1. advantageous Embodiments and developments of the invention are the subject the dependent claims.

The Internal combustion engine is equipped with two exhaust gas turbines connected in series provided in an exhaust line, wherein the exhaust line an output the near-engine exhaust gas turbine with an exhaust gas flow in the engine remote Exhaust gas turbine connects. The close-coupled exhaust gas turbine has a bridging Bypass on, with a blow-off valve positioned in the bypass, that in a turbine housing the engine-remote exhaust gas turbine is integrated. The blow-off valve points a collection room into which the bypass opens and the one over Opening cross-section with a turbine wheel of the engine exhaust gas turbine in conjunction stands, wherein in the mouth section an adjustable die is arranged. The collection space or the Opening cross-section is separated from the exhaust gas flow by a partition. Further points the partition and / or the die at least one recess and the die and / or the partition at least one projection, wherein the projection in shape, size and / or Position is formed corresponding to the recess, so that the Recess and the projection in the closed position of the die one Positive connection for closing of the mouth cross-section form.

On the one hand, such an internal combustion engine makes better use of the exergy in the exhaust gas by integrating the blow-off valve of the bypass into the turbine housing of the exhaust gas turbine remote from the engine, and on the other hand ensures tight closing of this blow-off valve, resulting in an even more efficient use of the exergy of the exhaust gas routed past the engine-side exhaust gas turbine seneströme is possible.

In An embodiment of the invention are on the partition wall in the mouth cross-section arranged between the plenum and the turbine wheel vanes, to the exhaust gas mass flow from the plenum an additional To give spin and the velocity energy, especially in the circumferential direction to increase; and the die is with receiving openings for receiving these vanes at least in the closed position formed the template.

In this case can the recess and the projection upstream and / or downstream of the guide vanes in the mouth section to be ordered.

In In another embodiment of the invention, the female mold is produced in its full open position a direct connection between the collecting space and the turbine outlet bypassing the turbine wheel to also bypass the engine To cause exhaust gas turbine.

The Inner peripheral side of the die is preferably adjacent directly the outer peripheral side of the Turbine wheel blades on.

In a still further embodiment of the invention is between the Outer peripheral side the die and the turbine housing a piston ring for sealing between the collecting space and the turbine outlet arranged.

The For example, the first close-coupled high-pressure exhaust gas turbine is part of a Exhaust gas turbocharger, as well contains a compressor in the intake of the internal combustion engine. The For example, a second low-pressure exhaust gas turbine is part of the engine an exhaust gas turbocharger, in addition contains a compressor in the intake tract of the internal combustion engine, or alternatively part of a compound turbine, which has its output power feeds into the internal combustion engine.

Above and other features and advantages of the invention will become apparent from the following description of preferred, non-limiting embodiments of the invention with reference to the accompanying drawings better understandable. Show:

1 a schematic representation of an internal combustion engine with two turbines connected in series (of two exhaust gas turbochargers) in the exhaust system according to a first preferred embodiment of the invention;

2 a schematic representation of an internal combustion engine with two turbines connected in series (an exhaust gas turbocharger and a compound turbine) in the exhaust system according to a second preferred embodiment of the invention;

3 a partial sectional view of the engine remote turbine of 1 or 2 in an enlarged view; and

4 a partial sectional view of the engine remote turbine of 1 or 2 in an enlarged view of the section X of 3 ,

Based on 1 and 2 First, two embodiments of an internal combustion engine (gasoline engine, diesel engine) with two turbines connected in series in the exhaust system are explained, in which the present invention can be applied in an advantageous manner.

In the 1 illustrated internal combustion engine 10 is with a two-stage supercharging with a first exhaust gas turbocharger close to the engine 12 and a second, exhaust gas turbocharger remote from the engine 14 provided, wherein the close-coupled exhaust gas turbocharger 12 as a small-scale loader, the high-pressure stage and the exhaust gas turbocharger remote from the engine 14 as a large-scale loader represents the low pressure stage.

The close-coupled exhaust gas turbocharger 12 includes a first exhaust gas turbine 16 in the exhaust system 18 the internal combustion engine 10 and a compressor 20 in her intake 22 , wherein the turbine wheel and the compressor wheel via a shaft 24 rotatably connected to each other. In a corresponding manner, the exhaust gas turbocharger remote from the engine comprises 14 a second exhaust gas turbine 26 in the exhaust system 18 and a compressor 28 in the intake tract 22 the internal combustion engine 10 , and turbine wheel and compressor wheel are over a shaft 30 rotatably coupled. Seen in the direction of flow is the compressor 28 of the engine exhaust turbocharger 14 the compressor 20 of the exhaust gas turbocharger close to the engine 12 upstream, whereas the exhaust gas turbine 26 of the engine exhaust turbocharger 14 the exhaust gas turbine 16 of the exhaust gas turbocharger close to the engine 12 is downstream.

The over the intake tract 22 the internal combustion engine 10 To be supplied combustion air flows through the compressor first 28 of the engine exhaust turbocharger 14 , undergoes a pre-compression in it, after leaving the compressor 28 in a first intercooler 32 cooled and then flows through the compressor close to the engine 20 , which is part of the high pressure stage. After the second compression in the compressor 20 becomes the under increased pressure combustion air in a second intercooler 34 cooled and then under boost pressure the cylinders of the internal combustion engine 10 fed.

On the exhaust side, the exhaust gas first flows through the first exhaust gas turbine close to the engine 16 the high-pressure stage in which the turbine wheel is driven. The exhaust gas relaxed to lower pressure is released after leaving the exhaust gas turbine 16 the second, downstream exhaust gas turbine 26 fed to the low-pressure stage and drives there with the remaining energy potential to the turbine wheel. After complete relaxation, the exhaust gas leaves the engine exhaust gas turbine 26 and is prior to draining yet another purge in an exhaust aftertreatment device 36 which comprises one or more catalysts and / or filter devices in a manner known to those skilled in the art.

In addition, the internal combustion engine 10 with an exhaust gas recirculation device 38 equipped with a return line 40 between the exhaust line 18 upstream of the near-engine exhaust gas turbine 16 and the intake tract 22 downstream of the second intercooler 34 having. In this return line 40 are an adjustable shut-off valve 42 and an exhaust gas cooler 44 arranged. To reduce the nitrogen oxide emissions can in certain operating conditions of the internal combustion engine 10 the check valve 42 opened and a part of the exhaust gas mass flow from the exhaust system 18 in the intake tract 22 be returned.

As in 1 is shown, furthermore, a close-coupled exhaust gas turbine 16 bridging bypass (channel) 46 provided upstream of the first exhaust gas turbine 16 from the exhaust system 18 branches off and downstream of the exhaust gas turbine 16 directly into the exhaust gas turbine remote from the engine 26 opens. To regulate the over the bypass 46 leading exhaust gas mass flow is a blow-off valve 48 provided, which in the housing of the exhaust engine remote from the engine 26 is integrated and explained in more detail below.

All adjustable components of the internal combustion engine 10 Depending on the state and operating variables, these are controlled via control signals from a control and control unit 50 regulated, in particular the check valve 42 in the exhaust gas recirculation device 38 as well as in the second exhaust gas turbine 26 integrated blow-off valve 48 ,

The blow-off via the bypass 46 allows a pressure reduction of the exhaust back pressure upstream of the high pressure turbine 16 , which in particular at high loads and speeds of the internal combustion engine 10 An overload of the turbine components can be avoided. That around the engine-near exhaust gas turbine 16 Guided exhaust is through the bypass 46 directly into the exhaust gas turbine remote from the engine 26 initiated so that the exergy contained in the exhaust gas for driving the turbine wheel of the engine remote low-pressure turbine 26 can be exploited. In this way, the overall efficiency of the internal combustion engine 10 improved. About a corresponding adjustment of the blow-off valve 48 in the exhaust gas turbine 26 but also the turbine wheel of this turbine 26 be circumvented, so that both a bypass of the turbine wheel of the exhaust gas near the engine 16 as well as a bypass of the turbine wheel of the engine exhaust gas turbine remote 26 is feasible.

2 shows a further embodiment of an internal combustion engine with two exhaust gas in the exhaust line one behind the other connected exhaust gas turbine, in which the present invention can be used. Here are in 2 the same or similar components as in the first embodiment in 1 with the same reference numerals, and a repeated description is partially omitted.

The in 2 shown construction of the internal combustion engine 10 differs from that of the first embodiment described above in that the exhaust gas turbocharger remote from the engine 14 the low-pressure stage through a turbocompound turbine 52 is replaced. The compound turbine 52 has a second exhaust gas turbine 54 in the exhaust system 18 and a transmission and conversion device 56 on. The turbine wheel of the exhaust gas turbine 54 and the transmission and conversion device 56 are about a wave 58 coupled. The performance of this second exhaust gas turbine 54 is after conversion of the speed by the transmission and converter device 56 on the speed level of the crankshaft of the internal combustion engine 10 over a wave 60 in the internal combustion engine 10 fed as in 2 indicated.

The swirl blow of the pressure in the exhaust line 18 in front of the near-engine exhaust gas turbine 16 becomes analogous to 1 over the bypass (channel) 46 directly into the engine exhaust gas turbine 54 the compound turbine 52 initiated. To regulate this exhaust gas mass flow via the bypass 46 is the blow-off valve 48 provided, which here in the housing of the engine exhaust gas turbine remote 54 is integrated and explained in more detail below.

The combustion air in the intake tract 22 is in this embodiment only via the compressor 20 of the exhaust gas turbocharger close to the engine 12 and the second intercooler 34 the internal combustion engine 10 fed. Due to the omission of the compressor 28 of the engine exhaust turbocharger 14 can in principle also the first intercooler 32 omitted, although he in 1 is still shown.

The operation and advantages of this internal combustion engine with two exhaust gas turbines connected in series 16 . 54 in the exhaust system 18 are essentially the same as the ones mentioned above first embodiment of 1 ,

Subsequently, reference will be made to 3 and 4 the structure of the second exhaust gas turbine 26 respectively. 54 and the integrated blow-off valve 48 explained in more detail how he in both embodiments of 1 and 2 equally advantageous.

In 2 is a section through the exhaust gas turbine 26 of the engine exhaust turbocharger 14 from 1 or the exhaust gas turbine 54 the compound turbine 52 from 2 shown. In the turbine housing 62 there is an exhaust gas flow 64 seen in the flow direction of the turbine wheel 66 upstream and in which the first exhaust gas turbine 16 of the exhaust gas turbocharger close to the engine 12 derived exhaust gas via the exhaust system 18 is initiated. From the spiral exhaust gas flow 64 the pressurized exhaust gas flows radially onto the turbine blades via a tapered throat cross-section 68 and puts this a driving impulse. In the course of the exhaust gas flows axially over the output 70 the turbine 26 . 54 from. The rotational movement of the turbine wheel 66 will be over the shaft 30 on the compressor wheel of the compressor 28 or over the wave 58 on the gear and converter device 56 transfer.

In addition to the exhaust gas flow 64 is separate from this in the turbine housing 62 a collection room 72 designed for exhaust gas, whose volume is significantly smaller than the volume of the exhaust gas flow 62 , In this collection room 72 the bypass opens 46 , which is the first engine near the exhaust gas turbine 16 bridged. Due to the relatively small volume of the collection space 72 and having a narrowest variable flow area downstream 74 can be a relatively high exhaust back pressure in the plenum 72 be generated.

The collection room 72 is above the aforementioned mouth cross-section 74 with the turbine wheel 66 in connection by the mouth cross-section 74 radially to the outside of the turbine blades 68 borders. The mouth cross-section 74 is located directly next to the mouth section of the exhaust gas flow 64 to the turbine wheel 66 , However, is against this flow-tight over a radially extending to the turbine longitudinal axis partition 76 separated.

Furthermore, an axially displaceable die 78 in the turbine housing 62 mounted, which is mounted axially displaceable and according to the arrow 80 between a closed position (left position in 3 ), in which the mouth cross-section 74 is shut off, and retracted open positions (right position in 3 ) Is displaced by means of an actuator, not shown. In the in 3 illustrated opening position of the die 78 is the mouth section 74 released, so that in the collection room 72 located and pressurized exhaust gas over the mouth cross-section 74 on the turbine wheel blades 68 meets and impels them with an impulse. In the opening position of the die 78 , which has the function of a valve member, becomes the turbine wheel 66 from the over the bypass 46 supplied exhaust gas driven.

The mouth cross-section 74 expediently extends annularly around the turbine wheel blades 68 , At the radial partition 76 between the exhaust gas 64 and the collection room 72 are vanes 82 fixedly arranged, which are streamlined so contoured that the exhaust gas from the plenum 72 must flow past it before it crosses the mouth 74 can happen. In this case, the exhaust gas experiences an additional swirl or an increase in the exhaust gas velocity, in particular in the circumferential direction, resulting in a better and more efficient energy transfer to the turbine wheel 66 is possible.

The vanes 82 are with closed die 78 in axially frontal receiving openings 84 taken up the die, whose axial depth is at least as large as the axial length of the vanes 82 is. That way, the die can 78 until the contact between its front and the partition 76 be closed, whereby the mouth cross-section 74 is completely locked.

The collection room 72 and the die acting as a valve member 78 together form the above-mentioned blow-off valve 48 , Also the vanes 82 are the blow-off valve 48 assigned. Optionally, on the vanes 82 but also be waived if the collection space 72 over the nozzle circumference 74 is designed spirally.

While in the embodiment of 3 the matrix 78 directly to the outer edge of the turbine blades 68 adjacent, alternatively, a housing-fixed component between turbine blades 68 and die 78 be provided (not shown). The advantage of in 3 but shown construction is that the die 78 in the open position as far axially from the partition 76 (in 3 to the right) can be moved away that the vanes 82 standing at the dividing wall 76 are fixed and extend in the axial direction, completely outside the receiving openings 84 in the face of the die 78 lie. In the axially furthest from the dividing wall 76 distant position is the partition 76 facing end face of the die 78 also before the turbine downstream side 86 , creating a direct flow path between the plenum 72 and the turbine outlet 70 for the exhaust from the Sam melraum 72 is released. This retracted position of the die 78 represents the Abblasestellung, wherein the exhaust gas with largely bypassing the turbine blades 68 directly to the turbine outlet 70 is directed and out of the exhaust gas turbine 26 . 54 flows.

The matrix 78 can assume any intermediate position between its most remote opening position and the closing position, which is in 3 symbolically by variable distance h between the end face of the die 78 and the partition 76 is indicated. Important positions are the closing position, in which the mouth cross-section 74 from the matrix 78 is locked, a first opening position in which the mouth cross-section 78 released, however, a direct flow connection between the plenum 72 and the turbine outlet 70 from the matrix 78 is locked, and a second opening or Abblaseposition in which the die 78 is withdrawn so far that its front side still after the turbine wheel downstream side 86 which creates an immediate flow path between the plenum 72 and turbine output 70 is released.

For the correct and reliable functioning of the relief valve described above 48 It is important that in the closed position of the die 78 the mouth cross-section 74 completely closed and the passage between the face of the die 78 and the partition 76 completely sealed. For this purpose, a special sealing construction is provided, which is described below with reference to 4 the enlarged detail view X of 3 will be described in more detail.

As in 4 exemplified is the sealing construction of the blow-off valve 48 in the manner of a labyrinth seal with a positive connection between the end face of the die 78 and the partition 76 in the closed position of the die 78 educated. This is in the die 78 facing side of the partition 76 a cone-shaped depression 88 trained and in the partition 76 facing end face of the die 78 is a cone-shaped projection 90 formed, which is substantially positive fit to the recess 88 in the partition 76 corresponds. deepening 88 and lead 90 are of course over the entire circumference of the mouth cross-section 74 ring-shaped.

Of course, the present invention is not limited to the specific configuration of the sealing construction of 4 limited. For example, the indentation must 88 and the lead 90 not necessarily be conical. Next can also each more than one recess 88 and more than a lead 90 be formed in a corresponding number. Furthermore, the depression 88 Of course, in the front of the die 78 and the lead 90 on the partition 76 be educated. In the case of multiple wells 88 and protrusions 90 These can also be alternately to partition 76 and die 78 be provided. While the recess 88 and the lead 90 in the embodiment of 4 upstream of the vanes 82 are provided, of course, they can also downstream of the vanes 82 or upstream and downstream of the vanes 82 if several wells 88 and projections 90 are provided, be formed.

The sealing construction from recess 88 and lead 90 ensures at least one necessary line contact between the partition 76 and the face of the die 78 in its closed position. In addition, the positive connection between depression causes 88 and lead 90 a certain guidance of the matrix 78 ,

The sealing construction causes a low-leakage conversion of Exergie the blow-off through the bypass 46 bypassing the near-engine exhaust gas turbine 16 right in front of the low-pressure turbine wheel 66 in speed energy, which is finally converted into mechanical work in the subsequent turbine wheel.

Like also in 4 shown, has the blow-off valve 48 continue a piston ring 92 on, in a recess of the turbine housing 62 between the turbine housing 62 and the matrix 78 is arranged. This piston ring 92 causes a seal between the plenum 72 and the turbine outlet 70 ,

Claims (9)

Internal combustion engine ( 10 ), with two exhaust gas turbines connected in series ( 16 . 26 . 54 ) in an exhaust gas line ( 18 ), wherein the exhaust gas line ( 18 ) an output of the exhaust gas near the engine ( 16 ) with an exhaust gas flow ( 64 ) in the engine exhaust gas turbine ( 26 . 54 ), and the engine exhaust gas turbine ( 16 ) a bridging bypass ( 46 ), wherein a blow-off valve ( 48 ) in the bypass ( 46 ) positioned in a turbine housing ( 62 ) of the engine exhaust gas turbine ( 26 . 54 ), wherein the blow-off valve ( 48 ) a collection room ( 72 ) into which the bypass ( 46 ) and which via an orifice cross-section ( 74 ) with a turbine wheel ( 66 ) of the engine exhaust gas turbine ( 26 . 54 ), wherein in the mouth cross-section ( 74 ) an adjustable die ( 78 ), and the collecting space ( 72 ) or the mouth cross-section ( 74 ) from the exhaust gas flow ( 64 ) by a partition wall ( 76 ), characterized in that the partition wall ( 76 ) and / or the die ( 78 ) at least one Deepening ( 88 ) and the die ( 78 ) and / or the partition ( 76 ) at least one projection ( 90 ), wherein the projection ( 90 ) in shape, size and / or position for deepening ( 88 ) is formed correspondingly, wherein the recess ( 88 ) and the lead ( 90 ) in the closed position of the die ( 78 ) a positive connection for closing the mouth cross section ( 74 ) form. Internal combustion engine according to claim 1, characterized in that on the partition wall ( 76 ) in the mouth section ( 74 ) between the collecting space ( 72 ) and the turbine wheel ( 66 ) Guide vanes ( 82 ) are arranged; and that the die ( 78 ) with receiving openings ( 84 ) for receiving the guide vanes ( 82 ) in the closed position of the die ( 78 ) is trained. Internal combustion engine according to claim 2, characterized in that the recess ( 88 ) and the lead ( 90 ) upstream and / or downstream of the guide vanes ( 82 ) in the mouth section ( 74 ) are arranged. Internal combustion engine according to one of claims 1 to 3, characterized in that the die ( 78 ) in its full open position, a direct connection between the collecting space ( 72 ) and the turbine outlet ( 70 ) bypassing the turbine wheel ( 66 ) generated. Internal combustion engine according to one of claims 1 to 4, characterized in that the Annenumfangsseite the die ( 78 ) directly to the outer peripheral side of the turbine wheel blades ( 68 ) adjoins. Internal combustion engine according to one of claims 1 to 5, characterized in that between the outer peripheral side of the die ( 78 ) and the turbine housing ( 62 ) a piston ring ( 92 ) for sealing between the collecting space ( 72 ) and the turbine outlet ( 70 ) is arranged. Internal combustion engine according to one of claims 1 to 6, characterized in that the engine-near exhaust gas turbine ( 16 ) Part of an exhaust gas turbocharger ( 12 ), which is also a compressor ( 20 ) in the intake tract ( 22 ) of the internal combustion engine ( 10 ) contains. Internal combustion engine according to one of claims 1 to 7, characterized in that the exhaust gas turbine remote from the engine ( 26 ) Part of an exhaust gas turbocharger ( 14 ), which is also a compressor ( 28 ) in the intake tract ( 22 ) of the internal combustion engine ( 10 ) contains. Internal combustion engine according to one of claims 1 to 7, characterized in that the exhaust gas turbine remote from the engine ( 54 ) Part of a compound turbine ( 52 ), which is its output power into the internal combustion engine ( 10 ) feeds.