SE2150098A1

SE2150098A1 - Exhaust Additive Dosing Arrangement, Turbine Outlet Assembly, Turbo Device, Internal Combustion Engine, and Vehicle

Info

Publication number: SE2150098A1
Application number: SE2150098A
Authority: SE
Inventors: Anders Gawell
Original assignee: Scania Cv Ab
Priority date: 2021-01-28
Filing date: 2021-01-28
Publication date: 2022-07-29
Also published as: SE545026C2; DE102021133451A1

Abstract

An airless exhaust additive dosing arrangement (10) is disclosed configured to supply an exhaust additive (20) to a stream of exhaust gas of an internal combustion engine (40). The dosing arrangement (10) comprises a supply tube (6) with an opening (8) for the supply of the exhaust additive (20) to the exhaust stream. The dosing arrangement (10) comprises a flow disturbing structure (11') arranged inside the supply tube (6). The present disclosure further relates to a turbine outlet assembly (1) for a turbo device (30), a turbo device (30) for an internal combustion engine (40), an internal combustion engine (40) comprising a turbo device (30), and vehicle (2) comprising an internal combustion engine (40).

Description

Exhaust Additive Dosing Arrangement, Turbine Outlet Assembly, Turbo Device, lnternal Combustion Engine, and Vehicle TECHNICAL FIELD The present disclosure relates to an airless exhaust additive dosing arrangement configuredto supply an exhaust additive to a stream of exhaust gas of an internal combustion engine.The present disclosure further relates to a turbine outlet assembly for a turbo device, a turbodevice for an internal combustion engine, an internal combustion engine comprising a turbo device, and a vehicle comprising an internal combustion engine.

BACKGROUND Turbo devices are used on internal combustion engines to increase performance and/or fuelefficiency of the engine. One type of turbo device is a turbocharger. A turbochargercomprises a turbine unit and a compressor, wherein the turbine unit is driven by exhaust gasof the engine to power the compressor. The compressor forces air to an air inlet of theengine which allows more fuel to be added and hence higher power output of the engine. Aturbocharger is an efficient means of supercharging an engine since it utilizes energy of the exhaust gasses of the engine to compress the inlet air.

Another type of turbo device is a turbo compound. A turbo compound also comprises turbineunit driven by exhaust gas of the engine. However, instead of powering a compressor, theenergy recovered from the exhaust gasses is sent to an output shaft of the engine or is usedfor another purpose, such as powering an electric generator. The produced electricity can beused to produce motive power to the vehicle in an electric machine or can be used to powerone or more other subsystems of the vehicle. A turbo compound is an efficient means ofincreasing the total fuel efficiency since it is capable of converting part of the energy of the exhaust gases into useful energy.

Environmental concerns, as well as emissions standards for motor vehicles, have led to thedevelopment of engines using exhaust additives, such as reducing agents for diesel, and/orethanol, exhaust gases. Reducing agents may comprise an aqueous urea solution and maybe used as a consumable in a Selective Catalytic Reduction SCR in order to lower nitrogenoxides NOX concentration in exhaust emissions from the internal combustion engine. ASelective Catalytic Reduction SCR system is a type of engine exhaust catalyst arrangementconfigured to convert the nitrogen oxides of exhaust gases into diatomic nitrogen and water using a reduction agent. The exhaust additive is usually injected into an exhaust conduit 2 directly upstream of a SCR Catalyst by an exhaust additive supply device protruding into the exhaust conduit.

The use of exhaust additives is associated with some problems and design difficulties. Oneproblem is that the exhaust gas of an internal combustion engine is hot, and the temperaturethereof substantially exceeds the boiling point of the exhaust additive in most cases.Moreover, the flow rate of exhaust additive through the exhaust additive supply device variesto a great extent. Therefore, boiling of exhaust additive may occur inside the exhaust additivesupply device in some cases, especially when the exhaust gases are hot and there is a lowflow rate of exhaust additive flowing through the exhaust additive supply device. Boiling ofexhaust additive inside the exhaust additive supply device may cause a varying supply ofexhaust additive to the stream of exhaust gas which in turn may cause an incorrect andinaccurate amount of exhaust additive supplied to the stream of exhaust. As a further resultthereof, the reduction efficiency of a catalyst may suffer leading to increased emission levels of the engine.

A further problem with the use of exhaust additives is the requirement for efficient mixing inorder to achieve uniform distribution of exhaust additive over the entire surface area of aSCR catalyst substrate. The space available for mixing is limited and the exhaust additive iscommonly injected into the exhaust stream shortly upstream of the SCR catalyst substrates.Attempts have been made to improve mixing of exhaust additives by providing injection ofthe exhaust additive further upstream in the exhaust system, for example in conjunction witha turbine unit arranged in the exhaust system. One such exhaust additive distribution deviceis described in the document WO 2018080371 A1. The device described therein is capableof adding exhaust additive to the exhaust stream in an efficient manner. However, in general,the injection of the exhaust additive further upstream an exhaust system adds to the problemof boiling inside an exhaust additive supply device because the exhaust gas is hotter further upstream an exhaust system than further downstream the exhaust system.

The problem of boiling inside an exhaust additive supply device can be alleviated bythermally isolating the exhaust additive supply device from walls of the exhaust conduitand/or from the stream of exhaust surrounding the exhaust additive supply device. However,a thermal isolation around an exhaust additive supply device adds to the size/diameter of theexhaust additive supply device. An increased size/diameter of the exhaust additive supplydevice adds to the pressure drop through the exhaust system which in turn can reduce tototal fuel efficiency of an engine. Moreover, solutions involving thermal isolation of an exhaust additive supply device add costs and complexity to the arrangement. Furthermore, 3 generally, on today's consumer market, it is an advantage if products, such as internalcombustion engines and associated components, systems, and arrangements, haveconditions and/or characteristics suitable for being manufactured and assembled in a cost- efficient manner.

SUMMARYlt is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by an airless exhaustadditive dosing arrangement configured to supply an exhaust additive to a stream of exhaustgas of an internal combustion engine. The dosing arrangement comprises a supply tube withan opening for the supply of the exhaust additive to the exhaust stream. The dosing arrangement comprises a flow disturbing structure arranged inside the supply tube.

Since the dosing arrangement comprises a flow disturbing structure arranged inside thesupply tube, a more even supply of exhaust additive can be provided also in cases of boilingof exhaust additive inside the supply tube. This because the flow disturbing structure canreduce the bubble size, and/or preventing a bubble from pushing liquid in front of it, whichcan even out and lower pressure variations generated by the formation of bubbles inside the supply tube.

Moreover, since the flow disturbing structure is arranged inside the supply tube, the flowdisturbing structure will not have an impact on the flow of exhaust gases around the supplytube. Furthermore, because the flow disturbing structure can provide a more even supply ofexhaust additive also in cases of boiling of exhaust additive inside the supply tube, the needfor thermal isolation around the supply tube is circumvented, or at least reduced, which in turn provides conditions for a low pressure drop of exhaust gas flowing past the supply tube. ln addition, because the flow disturbing structure can provide a more even supply of exhaustadditive also in cases of boiling of exhaust additive inside the supply tube, conditions areprovided for positioning the supply tube further upstream an exhaust system withoutobtaining a highly varying supply of exhaust additive caused by boiling. ln addition, due tothe features of the dosing arrangement, conditions are provided for arranging the supply tubefurther upstream an exhaust system with a reduced need for thermal isolation therebyproviding conditions for a low pressure drop of exhaust gas flowing past the supply tube also at positions further upstream an exhaust system.

Accordingly, a dosing arrangement is provided overcoming, or at least alleviating, at leastsome of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

The feature that the exhaust additive dosing arrangement is an airless exhaust additivedosing arrangement means that the exhaust additive is supplied to the supply tube without the use of pressurized air.

Optionally, the supply tube comprises a section configured to protrude into an exhaustconduit of the internal combustion engine, and wherein the flow disturbing structure isarranged inside the section of the supply tube. Thereby, a dosing arrangement is providedhaving conditions for further lowering variations of the supply of exhaust additive caused byboiling. This because the section protruding into the exhaust conduit is subjected to hightemperatures and boiling therein is likely to occur in some operational conditions. Moreover,since the flow disturbing structure is arranged inside the section of the supply tube, the needfor external thermal isolation thereof is circumvented, or at least reduced, which in turnprovides conditions for a low pressure drop of exhaust gas flowing past the section of the supply tube.

Optionally, the flow disturbing structure is arranged adjacent to the opening of the supplytube. Thereby, a dosing arrangement is provided having conditions for further loweringvariations of the supply of exhaust additive caused by boiling. This because boiling is most likely to occur in the region of the opening of the supply tube.

Optionally, the opening is an open end of the supply tube. Thereby, a simple and cost-efficient dosing arrangement is provided having conditions for generating a more even supply of exhaust additive also in cases of boiling of exhaust additive inside the supply tube.

Optionally, the flow disturbing structure is at least partially formed by a flow disturbing bodyarranged inside the supply tube. Thereby, a simple and effective dosing arrangement isprovided capable of generating a more even supply of exhaust additive also in cases of boiling of exhaust additive inside the supply tube.

Optionally, the flow disturbing structure is at least partially formed by a wire arranged insidethe supply tube. Thereby, a dosing arrangement is provided in which the flow disturbing structure can reduce the bubble size, and/or preventing a bubble from pushing liquid in front of it, in an improved manner. Thereby, a dosing arrangement is provided having furtherimproved conditions for generating a more even supply of exhaust additive also in cases ofboiling of exhaust additive inside the supply tube. ln addition, a dosing arrangement isprovided having conditions and/or Characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the wire is formed as a coil-spring. Thereby, a dosing arrangement is provided inwhich the flow disturbing structure can reduce the bubble size, and/or preventing a bubblefrom pushing liquid in front of it, in a further improved manner. Thereby, a dosing arrangement is provided having further improved conditions for generating a more even supply of exhaust additive also in cases of boiling of exhaust additive inside the supply tube. ln addition, a dosing arrangement is provided having conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the flow disturbing structure is at least partially formed by grooves and/orprotrusions provided in an inner surface of the supply tube. Thereby, a simple and effectivedosing arrangement is provided capable of generating a more even supply of exhaustadditive also in cases of boiling of exhaust additive inside the supply tube. Moreover, adosing arrangement is provided having conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the dosing arrangement comprises a pump configured to pump exhaust additivefrom an exhaust additive storage unit to the supply tube. Thereby, a simple and effectivedosing arrangement is provided capable of generating a more even supply of exhaust additive also in cases of boiling of exhaust additive inside the supply tube.

According to a second aspect of the invention, the object is achieved by a turbine outletassembly for a turbo device, wherein the assembly comprises a turbine outlet duct and adosing arrangement according to some embodiments of the present disclosure, wherein thesupply tube comprises a section with the opening for the supply of the exhaust additive, and wherein the section is arranged in the turbine outlet duct.

Since the turbine outlet assembly comprises a dosing arrangement according to someembodiments, a turbine outlet assembly is provided capable of a more even supply ofexhaust additive to exhaust gas flowing through the turbine outlet duct also in cases of boiling of exhaust additive inside the supply tube. 6 Furthermore, since the section of the supply tube comprising the opening is arranged in theturbine outlet duct, conditions are provided for an improved mixing of exhaust additive and exhaust gas downstream of the turbine outlet assembly and upstream of a catalyst.

Moreover, since the flow disturbing structure is arranged inside the supply tube, the flowdisturbing structure will not have an impact on the flow of exhaust gases in the turbine outletduct. Furthermore, because the flow disturbing structure can provide a more even supply ofexhaust additive also in cases of boiling of exhaust additive inside the supply tube, the needfor thermal isolation around the supply tube is circumvented, or at least reduced, which inturn provides conditions for a low pressure drop of exhaust gas flowing through the turbine outlet duct.

Accordingly, a turbine outlet assembly is provided overcoming, or at least alleviating, at leastsome of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the assembly further comprises a diffuser pipe arranged in the turbine outlet duct,and wherein the section is arranged in the diffuser pipe. Since the section of the supply tubecomprising the opening is arranged in the diffuser pipe, conditions are provided for animproved mixing of exhaust additive and exhaust gas downstream of the turbine outletassembly and upstream of a catalyst. Moreover, since the flow disturbing structure isarranged inside the supply tube, the flow disturbing structure will not have an impact on theflow of exhaust gases in the diffuser pipe. Furthermore, because the flow disturbing structurecan provide a more even supply of exhaust additive also in cases of boiling of exhaustadditive inside the supply tube, the need for thermal isolation around the supply tube iscircumvented, or at least reduced, which in turn provides conditions for a low pressure drop of exhaust gas flowing through the diffuser pipe.

Optionally, the diffuser pipe is configured to conduct exhaust gas in a direction from a firstend towards a second end of the diffuser pipe, and wherein the opening of the supply tube is arranged closer to the first end than the second end of the diffuser pipe.

Optionally, the assembly comprises a turbine unit configured to rotate during operation of aturbo device comprising the assembly, wherein the assembly comprises a distribution devicearranged on the turbine unit, and wherein the supply tube is arranged to supply an exhaustadditive onto the distribution device. Thereby, exhaust additive supplied to the distribution device is dispersed in the exhaust steam utilising the centrifugal force of the rotating 7 distribution device. Due to the large amounts of kinetic energy supplied to the dosed exhaustadditive, the high temperatures at the turbine outlet, and the highly turbulent flow at the turbine outlet, highly effective evaporation and mixing of the exhaust additive is obtained.

Moreover, since the dosing arrangement comprises the flow disturbing structure arrangedinside the supply tube, the opening of the supply tube is allowed to be arranged close to thedistribution device and still be able to supply accurate amounts of exhaust additive onto thedistribution device with a reduced or circumvented need for thermal isolation around the supply tube.

Optionally, the distribution device is cup-shaped. Thereby, the distribution device will functionas a rotary cup atomizer. Since the opening of the supply tube can be positioned within thecup, and since the geometry of the cup can be optimised to prevent back-flow from a rim ofthe cup-shaped distribution device, this solution reduces the risk of exhaust additive being unintentionally deposited on turbine surfaces.

Optionally, the distribution device may comprise a receiving surface forming a patternedfacial surface. This patterned facial surface may be used to control and optimise the distribution of exhaust additive in the exhaust stream.

Optionally, the exhaust additive distribution device may comprise a radial wall, wherein thereceiving surface exhaust additive distribution device is an inner face of the radial wall, andwherein the exhaust additive distribution device comprises a distribution surface of an orificeformed in the radial wall, the orifice extending between an inner face of the radial wall and anouter surface of the radial wall. Such a solution resembles current production injector nozzlesand thus such a distribution device may be obtained by adjustment of current productionlines. According to such embodiments, the distribution device may comprise a matingsurface with an exhaust additive dosing unit, thus helping to avoid undesired leakage of the exhaust additive.

According to a third aspect of the invention, the object is achieved by a turbo device for aninternal combustion engine, wherein the turbo device comprises a turbine unit configured tobe driven by exhaust gas of the internal combustion engine, and wherein turbo devicecomprises a turbine outlet assembly according to some embodiments of the present disclosure. 8 Since the turbo device comprises a turbine outlet assembly according to some embodiments,a turbo device is provided having conditions for generating a more even supply of exhaustadditive to exhaust gas flowing through the turbine outlet duct also in cases of boiling of exhaust additive inside the supply tube.

Furthermore, since the section of the supply tube comprising the opening is arranged in theturbine outlet duct, conditions are provided for an improved mixing of exhaust additive and exhaust gas downstream of the turbine outlet assembly and upstream of a catalyst.

Accordingly, a turbo device is provided overcoming, or at least alleviating, at least some ofthe above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

According to a fourth aspect of the invention, the object is achieved by an internalcombustion engine comprising a turbo device according to some embodiments of the present disclosure.

Since the internal combustion engine comprises a turbo device according to someembodiments, an internal combustion engine is provided overcoming, or at least alleviating,at least some of the above-mentioned problems and drawbacks. As a result, the above- mentioned object is achieved.

Optionally, the internal combustion engine is a compression ignition engine and wherein thesupply tube is configured to supply an aqueous urea solution to exhaust gas flowing through an exhaust conduit of the internal combustion engine.

According to a fifth aspect of the invention, the object is achieved by a vehicle comprising an internal combustion engine according to some embodiments of the present disclosure. 9 Since the vehicle comprises an internal combustion engine according to some embodiments,a vehicle is provided overcoming, or at least alleviating, at least some of the above- mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGSVarious aspects of the invention, including its particular features and advantages, will bereadily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which: Fig. 1 schematically illustrates a vehicle according to some embodiments of the presentdisclosure, Fig. 2 schematically illustrates an internal combustion engine of the vehicle illustrated in Fig.1, Fig. 3 illustrates a cross section of a turbine outlet assembly according to someembodiments, and Fig. 4 illustrates an exhaust additive dosing arrangement according to some further embodiments.

DETAILED DESCRIPTIONAspects of the present invention will now be described more fully. Like numbers refer to likeelements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 schematically illustrates a vehicle 2 according to some embodiments of the presentdisclosure. According to the illustrated embodiments, the vehicle 2 is a truck, i.e. a heavyvehicle. However, according to further embodiments, the vehicle 2, as referred to herein,may be another type of manned or unmanned vehicle for land or water based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a ship, a boat, or the like.

The vehicle 2 comprises an internal combustion engine 40. According to the illustratedembodiments, the internal combustion engine 40 is configured to provide motive power to the vehicle 2 via wheels 41 of the vehicle 2.

Fig. 2 schematically illustrates the internal combustion engine 40 of the vehicle 2 illustratedin Fig. 1. According to the illustrated embodiments, the internal combustion engine 40 is adiesel engine, i.e. a type of compression ignition engine. According to further embodiments,the combustion engine 40, as referred to herein may be an Otto engine with a spark-ignitiondevice, wherein the Otto engine may be configured to run on a gaseous fuel, petrol, alcohol,similar volatile fuels, or combinations thereof. For reasons of brevity and clarity, the internalcombustion engine 40 is in some places herein referred to as the combustion engine 40, orsimply the engine 40. According to some embodiments, the combustion engine 40, asreferred to herein, may be configured to power another unit than a vehicle, such as for example an electric generator.

The combustion engine 40 comprises a turbo device 30. As is further explained herein, theturbo device 30 comprises a turbine unit configured to be driven by exhaust gas of theinternal combustion engine 40. According to the illustrated embodiments, the turbo device 30is a turbocharger, i.e. a charging device configured to compress air to an air inlet 42 of thecombustion engine 40. Thus, according to these embodiments, the turbine unit of the turbodevice 30 is connected to the compressor. According to further embodiments, the turbodevice 30, as referred to herein, may be a turbo compound device wherein the turbine unit isconnected to an output shaft of the combustion engine 40 or to another shaft or type of device configured to produce useful energy by the rotation of the turbine unit.

According to the illustrated embodiments, the combustion engine 40 comprises an air filterunit 43 and a charge air cooler 44. The compressor of the turbo device 30 is configured toforce air from the air filter unit 43 to the air inlet 42 of the engine 40. The charge air cooler 44is arranged between the compressor of the turbo device 30 and the air inlet 42 of thecombustion engine 40. The charge air cooler 44 is configured to cool the compressed airbefore the air is conducted to the air inlet 42. ln this manner, the power output and fuelefficiency of the combustion engine 40 can be improved. Moreover, according to theillustrated embodiments, the combustion engine 40 comprises a Selective Catalytic Reduction SCR catalyst 45 arranged downstream of the turbine unit of the turbo device 30.

Fig. 3 illustrates a cross section of a turbine outlet assembly 1 according to someembodiments. According to the illustrated embodiments, the turbine outlet assembly 1comprises a turbine unit 19. ln such embodiments, the turbine outlet assembly 1, as referredto herein, may also be referred to as a turbine assembly for a turbo device. The turbine unit19 is configured to be driven by exhaust gas of an internal combustion engine, such as the combustion engine 40 illustrated in Fig. 2. The turbine outlet assembly 1 may form part of 11 turbo device in the form of a turbocharger or a turbo device in the form of a turbo compounddevice. ln other Words, the turbo device 30 illustrated in Fig. 2 may comprise a turbine out|etassembly 1 according to the embodiments illustrated in Fig. 3. Therefore, below, simultaneous reference is made to Fig. 2 and Fig. 3 if not indicated othenNise.

The turbine unit 19 is configured to rotate around a rotation axis Ra during operation of aturbo device 30 comprising the turbine out|et assembly 1. ln Fig. 3, the cross section is madein a plane comprising the rotation axis Ra of the turbine unit 19. The turbine unit 19comprises a turbine 19' and a shaft 19" connected to the turbine 19". According to theillustrated embodiments, the turbine 19' and the shaft 19" are formed by one piece ofcoherent material. According to further embodiments, the turbine 19' and the shaft 19" maybe separate parts wherein the turbine 19' is connected to the shaft 19". ln embodiments inwhich the turbine out|et assembly 1 forms part of a turbo device 30 in the form of aturbocharger, the shaft 19" of the turbine unit 19 is connected to a compressor, such as acompressor explained with reference to Fig. 2. ln embodiments in which the turbine out|etassembly 1 forms part of a turbo device 30 in the form of a turbo compound device, the shaft19" of the turbine unit 19 may be connected to an output shaft of a combustion engine 40 orto another shaft or type of device configured to produce useful energy by the rotation of the turbine unit 19.

The turbine out|et assembly 1 comprises a turbine housing 51. The turbine unit 19 isarranged to rotate in the turbine housing 51. The turbine housing 51 comprises a volute 52.The volute 52 may also be referred to as a turbine volute. The volute 52 is fluidly connectedto an exhaust manifold of a combustion engine, such as the exhaust manifold 46 of thecombustion engine 40 illustrated in Fig. 2. The flow of exhaust gas from the volute 52through the turbine 19' causes rotation of the turbine unit 19 around the rotation axis Ra. Theturbine out|et assembly 1 further comprises a turbine out|et duct 3 arranged downstream ofthe turbine unit 19 and a diffuser pipe 5 arranged in the turbine out|et duct 3. The diffuserpipe 5 is arranged in the turbine out|et duct 3 such that a gap 9 is formed between an innersurface 3' of the turbine out|et duct 3 and an outer surface 5' of the diffuser pipe 5. Accordingto the illustrated embodiments, the turbine out|et duct 3 form part of the turbine housing 51but may also be a separate part attached to the turbine housing 51. However, since theturbine out|et duct 3 form part of the turbine housing 51 according to the illustratedembodiments, the turbine out|et duct 3, as referred to herein, may also be referred to as a turbine housing or a portion of a turbine housing. 12 The turbine outlet assembly 1 comprises a wastegate valve 61. ln Fig. 3, the wastegate valve61 is illustrated in a closed position. According to the illustrated embodiments, the wastegatevalve 61 is fluidly connected to the volute 52. The turbine outlet assembly 1 comprises awastegate gas outlet 7 connected to the gap 9 between the turbine outlet duct 3 and thediffuser pipe 5. According to the illustrated embodiments, the wastegate gas outlet 7 isconfigured to conduct wastegate gas to the gap 9 in a direction d2 transversal to a centreaxis Ca of the diffuser pipe 5. When the wastegate valve 61 is in the closed position, thewastegate valve 61 closes a fluid connection between the volute 52 and the wastegate gasoutlet 7. Thereby, when the wastegate valve 61 is in the closed position, all exhaust gas from the volute 52 is conducted through the turbine 19' of the turbine unit 19 to the diffuser pipe 5.

The wastegate valve 61 is controllable from the closed position to an open position in whichthe wastegate valve 61 opens a fluid connection between the volute 52 and the wastegategas outlet 7. Thereby, when the wastegate valve 61 is in the open position, part of theexhaust gas from the volute 52 is bypassing the turbine 19' of the turbine unit 19 and insteadflows through the wastegate valve 61 and the wastegate gas outlet 7 into the gap 9 between the inner surface 3' of the turbine outlet duct 3 and the outer surface 5' of the diffuser pipe 5.

According to the illustrated embodiments, the wastegate valve 61 is pivotally arrangedaround a pivot axis Pa between the open and closed position. However, according to furtherembodiments, the wastegate valve 61 may be arranged to be controlled between the openand closed positions in another manner, such as by a linear displacement. The wastegatevalve 61 may be controlled between the open and closed positions by an actuator, such as apneumatic and/or electric actuator in a conventional manner. As an example, the wastegatevalve 61 may be controlled to the open position when it is wanted to limit a rotational speedof the turbine unit 19, when it is wanted to limit a current boost pressure, and/or when it is wanted to increase temperature of exhaust gas downstream of the turbine outlet assembly 1.

As can be seen in Fig. 3, according to the illustrated embodiments, the wastegate valve 61 isarranged inside the turbine housing 51 and the wastegate valve 61 is in direct fluidconnection with the volute 52. According to further embodiments, the wastegate valve 61may not be arranged inside the turbine housing 51 and may be fluidly connected to anotherportion of an exhaust conduit between an exhaust outlet of a combustion engine and the turbine 19' of the turbine unit 19.

Moreover, as can be seen in Fig. 3, the turbine outlet assembly 1 comprises an exhaust additive dosing arrangement 10. The exhaust additive dosing arrangement 10 is an airless 13 exhaust additive dosing arrangement 10 meaning that the exhaust additive 20 is supplied toexhaust gas without the use of pressurized air as is the case in some other types of exhaustadditive dosing arrangements. For reasons of brevity and clarity, the airless exhaust additivedosing arrangement 10 is in some places herein referred to as the "exhaust additive dosingarrangement" 10, or simply the "dosing arrangement" 10. The dosing arrangement 10 isconfigured to supply an exhaust additive 20 to a stream of exhaust gas of an internalcombustion engine. The internal combustion engine may be an internal combustion engine40 according to the embodiments illustrated in Fig. 2. The dosing arrangement 10 comprisesa supply tube 6 with an opening 8 for the supply of the exhaust additive 20 to the exhaust stream.

According to the illustrated embodiments, the supply tube 6 comprises a section 6' protrudinginto an exhaust conduit 3a, 5a of the internal combustion engine. The section 6' comprisesthe opening 8 for the supply of the exhaust additive 20. According to the illustratedembodiments, the exhaust conduit 3a, 5a is formed by the turbine outlet duct 3 and thediffuser pipe 5 of the turbine outlet assembly 1. The turbine outlet duct 3 and the diffuser pipe5 of the turbine outlet assembly 1 may thus also be referred to as exhaust conduits 3a, 5a. lnmore detail, according to the illustrated embodiments, the section 6' of the supply tube 6protrudes into the turbine outlet duct 3 and the diffuser pipe 5 such that the opening 8 ispositioned inside the diffuser pipe 5. The section 6' of the supply tube 6 is thus arrangedinside the turbine outlet duct 3 and inside the diffuser pipe 5. Moreover, according to theillustrated embodiments, the supply tube 6 is arranged such that a centre axis Ca of thediffuser pipe 5 extends through the opening 8 of the supply tube 6. The supply tube 6 isconfigured to supply exhaust additive 20, such as an aqueous urea solution, to exhaust gasflowing through the diffuser pipe 5. The turbine outlet assembly 1, as referred to herein, may comprise at least part of the exhaust additive dosing arrangement 10.

As explained above, the exhaust additive dosing arrangement 10 is an airless exhaustadditive dosing arrangement 10 meaning that the exhaust additive dosing arrangement 10 isconfigured to pump exhaust additive 20 using a pump 32 instead of using compressed air assome other types of exhaust additive dosing arrangements. ln more detail, according to theillustrated embodiments, the exhaust additive dosing arrangement 10 comprises an exhaustadditive storage unit 34 configured to accommodate exhaust additive 20 and a pump 32configured to pump exhaust additive 20 from the exhaust additive storage unit 34 to thesupply tube 6. Moreover, the exhaust additive dosing arrangement 10 may comprise some further components 36 between the pump 32 and the supply tube 6. ln Fig. 3, such further 14 components 36 are indicated with the reference sign 36 and may comprise further tubing, a dosing valve, and the like.

According to embodiments herein, the dosing arrangement 10 comprises a flow disturbingstructure 11' arranged inside the supply tube 6. The flow disturbing structure 11' is arrangedto cause disturbance of flow of exhaust additive 20 through the supply tube 6. ln this manner,a more even supply of exhaust additive 20 can be provided also in cases of boiling ofexhaust additive 20 inside the supply tube 6. This because the flow disturbing structure 11'can reduce the bubble size, and/or preventing a bubble from pushing liquid in front of it,which can even out and lower pressure variations generated by the formation of bubbles inside the supply tube 6.

Furthermore, because the flow disturbing structure 11' can provide a more even supply ofexhaust additive 20 also in cases of boiling of exhaust additive 20 inside the supply tube 6,the need for thermal isolation around the supply tube 6 is circumvented, or at least reduced,which in turn provides conditions for a low pressure drop of exhaust gas flowing past the supply tube 6. ln addition, because the flow disturbing structure 11' can provide a more even supply ofexhaust additive 20 also in cases of boiling of exhaust additive 20 inside the supply tube 6,conditions are provided for positioning the supply tube 6 further upstream an exhaust systemwithout obtaining a highly varying supply of exhaust additive 20, as is the case according tothe illustrated embodiments. ln addition, due to the features of the dosing arrangement 10,conditions are provided for arranging the supply tube 6 further upstream an exhaust systemwith a reduced need for thermal isolation thereby providing conditions for a low pressuredrop of exhaust gas flowing past the supply tube 6 also at positions further upstream an exhaust system, as is the case according to the illustrated embodiments.

According to the embodiments illustrated in Fig. 3, the supply tube 6 is configured to supplyexhaust additive 20 at a position directly downstream of the turbine 19' of the turbine unit 19.However, according to further embodiments of the herein described, the supply tube 6 of thedosing arrangement 10 may be configured to supply exhaust additive 20 at another positionof an exhaust system, such as at a position further down an exhaust system of a combustion engine.

As can be seen in Fig. 3, according to the illustrated embodiments, the flow disturbing structure 11' is arranged inside the section 6' of the supply tube 6 which protrudes into the exhaust conduit 3a, 5a. Moreover, the flow disturbing structure 11' is arranged adjacent tothe opening 8 of the supply tube 6. This section 6' of the supply tube is subjected to hightemperatures and boiling therein is likely to occur in some operational conditions. Since theflow disturbing structure 11' is arranged inside this section 6' of the supply tube 6, a dosingarrangement 10 is provided having conditions for further lowering variations of the supply of exhaust additive 20 caused by boiling.

Furthermore, according to the illustrated embodiments, the flow disturbing structure 11' isarranged along the full length of the section 6' of the supply tube 6 which protrudes into theexhaust conduit 3a, 5a. According to further embodiments, the flow disturbing structure 11'may be arranged along more than 50% of the length of the section 6' of the supply tube 6 protruding into the exhaust conduit 3a, 5a.

According to the embodiments illustrated in Fig. 3, the flow disturbing structure 11' is at leastpartially formed by a flow disturbing body 11 arranged inside the supply tube 6. ln moredetail, according to these embodiments, the flow disturbing structure 11' is at least partiallyformed by a wire 11" arranged inside the supply tube 6, wherein the wire 11" is formed as acoil-spring. Thereby, a dosing arrangement 10 is provided in which the flow disturbingstructure 11' can reduce the bubble size, and/or preventing a bubble from pushing liquid infront of it, in a further improved manner. Thereby, a dosing arrangement 10 is providedhaving further improved conditions for generating a more even supply of exhaust additive 20also in cases of boiling of exhaust additive 20 inside the supply tube 6. ln addition, a dosingarrangement 10 is provided having conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

According to the illustrated embodiments, the opening 8 is an open end of the supply tube 6.The open end of the supply tube 6 may have a reduced diameter as compared to portions ofthe supply tube 6 further upstream of the opening 8. ln this manner, a flow disturbing body11, such as a wire 11", can be kept securely in place during operation of the dosing arrangement 10.

Fig. 4 illustrates an exhaust additive dosing arrangement 10 according to some furtherembodiments. The exhaust additive dosing arrangement 10 illustrated in Fig. 4 maycomprise the same features, functions, and advantages as the exhaust additive dosing arrangement 10 explained with reference to Fig. 3, with some differences explained below. 16 The turbine outlet assembly 1 illustrated in Fig. 3 may comprise an exhaust additive dosingarrangement 10 according to the embodiments illustrated in Fig. 4. According to suchembodiments, the exhaust additive dosing arrangement 10 may be arranged such that thesection 6' of the supply tube 6 protrudes into the turbine outlet duct 3 and the diffuser pipe 5and such that the opening 8 is positioned inside the diffuser pipe 5 in the same manner asexplained with reference to Fig. 3. However, the exhaust additive dosing arrangement 10according to the embodiments illustrated in Fig. 4 may also be used to supply an exhaustadditive to a stream of exhaust gas at another location of an exhaust system of an internalcombustion engine, such as at a position further down an exhaust system of a combustion engine.

Also in these embodiments, the exhaust additive dosing arrangement 10 is an airlessexhaust additive dosing arrangement 10 meaning that the exhaust additive dosingarrangement 10 is configured to pump exhaust additive 20 using a pump 32 instead of usingcompressed air as some other types of exhaust additive dosing arrangements. ln moredetail, according to the illustrated embodiments, the exhaust additive dosing arrangement 10comprises an exhaust additive storage unit 34 configured to accommodate exhaust additive20 and a pump 32 configured to pump exhaust additive 20 from the exhaust additive storageunit 34 to the supply tube 6. Moreover, the exhaust additive dosing arrangement 10 maycomprise some further components 36 between the pump 32 and the supply tube 6. ln Fig.3, such further components 36 are indicated with the reference sign 36 and may comprise further tubing, a dosing valve, and the like.

According to the embodiments illustrated in Fig. 4, the flow disturbing structure 11' is at leastpartially formed by grooves 12 and protrusions 13 provided in an inner surface of the supplytube 6. Thereby, a simple and effective dosing arrangement 10 is provided capable ofgenerating a more even supply of exhaust additive 20 also in cases of boiling of exhaustadditive 20 inside the supply tube 6. This because the grooves 12 and the protrusions 13provided in an inner surface of the supply tube 6 disturbs the flow of exhaust additive 20inside the supply tube 6 and thereby can reduce the bubble size, and/or preventing a bubblefrom pushing liquid in front of it, which can even out and lower pressure variations generatedby the formation of bubbles inside the supply tube 6. The grooves 12 and/or protrusions 13may be formed by machining the inner surface of the supply tube 6. As a result thereof, adosing arrangement 10 is provided having conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner. 17 Also in these embodiments, the opening 8 is an open end of the supply tube 6. As can beseen in Fig. 4, according to the illustrated embodiments, the flow disturbing structure 11' isarranged inside the section 6' of the supply tube 6 which is configured to protrude into anexhaust conduit. Moreover, the flow disturbing structure 11' is arranged adjacent to theopening 8 of the supply tube 6. This section 6' of the supply tube is subjected to hightemperatures and boiling therein is likely to occur in some operational conditions. However,since the flow disturbing structure 11' is arranged inside this section 6' of the supply tube 6, adosing arrangement 10 is provided having conditions for further lowering variations of the supply of exhaust additive 20 caused by boiling.

The embodiments of the flow disturbing structure 11' described herein may be combined.That is, according to some embodiments, the supply tube 6 of the dosing arrangement 10may comprise grooves 12 and/or protrusions 13 provided in an inner surface of the supplytube 6 and a flow disturbing body 11, such as a wire 11", arranged inside the supply tube 6.Thereby, a more even supply of exhaust additive 20 can be provided also in cases of boilingof exhaust additive 20 inside the supply tube 6. Moreover, the flow disturbing body 11 can be more securely retained inside the supply tube 6.

The following is explained with simultaneous reference to Fig. 2 - Fig. 4. According toembodiments herein, the internal combustion engine 40 is a compression ignition engine andthe supply tube 6 is configured to supply an aqueous urea solution to exhaust gas flowingthrough the diffuser pipe 5. According to further embodiments, the combustion engine 40, asreferred to herein may be an Otto engine with a spark-ignition device, wherein the Ottoengine may be configured to run on a gaseous fuel, petrol, alcohol, similar volatile fuels, orcombinations thereof. As indicated in Fig. 2, the combustion engine 40 may comprise aSelective Catalytic Reduction SCR catalyst 45 arranged downstream of the turbo device 30and thus also downstream of the turbine outlet assembly 1. The SCR catalyst 45 mayconvert nitrogen oxides of exhaust gases into diatomic nitrogen and water using the exhaust additive 20 added to exhaust gas by the supply tube 6 of the dosing arrangement 10.

As can be seen in Fig. 3, the diffuser pipe 5 is configured to conduct exhaust gas in adirection d1 from a first end 15 towards a second end 17 of the diffuser pipe 5. The opening8 of the supply tube 6 is arranged closer to the first end 15 than the second end 17 of thediffuser pipe 5. Thus, according to the illustrated embodiments, the supply tube 6 isconfigured to supply an exhaust additive to exhaust gas at a location closer to the first end15 than the second end 17 of the diffuser pipe 5. Moreover, according to the embodiments illustrated in Fig. 3, the assembly 1 comprises a distribution device 23 arranged on the 18 turbine unit 19, wherein the supply tube 6 is arranged to supply an exhaust additive onto thedistribution device 23. The distribution device 23 is arranged at a centre of the turbine unit 19 meaning that the rotational axis Ra of the turbine unit 19 extends through the distribution device 23. As is apparent from Fig. 3, according to the i||ustrated embodiments, the rotational axis Ra of the turbine unit 19 coincides with the centre axis Ca of the diffuser pipe 5.According to the i||ustrated embodiments, the distribution device 23 form part of the turbine19' of the turbine unit 19, i.e. the distribution device 23 and the turbine 19' are formed by onepiece of coherent material. According to further embodiments, the distribution device 23 maybe a separate part attached to the turbine unit 19 for example by welding and/or by one or more fastening elements.

According to the i||ustrated embodiments, the distribution device 23 is cup-shaped and thesupply tube 6 protrudes into an open face of the cup-shaped distribution device 23 such thatthe opening 8 of the supply tube 6 is positioned inside the cup-shaped distribution device 23.Since the distribution device 23 corotates with the turbine unit 19 at high rotational speeds,an efficient distribution and atomisation of exhaust additive is provided. ln addition, the cup-shape of the distribution device 23 prevents back-flow from a rim of the cup-shapeddistribution device 23 and reduces the risk of exhaust additive being unintentionally deposited on surfaces of the turbine 19".

Since the supply tube 6 comprises the flow disturbing structure 11' arranged inside thesupply tube 6, the supply tube 6 can be arranged in close proximity to the turbine 19' of theturbine unit 19 and the opening 8 of the supply tube is allowed to be arranged close to thedistribution device 23 and still be able to supply accurate amounts of exhaust additive 20onto the distribution device 23 with a reduced or circumvented need for thermal isolationaround the supply tube 6. Accordingly, due to the features of the supply tube 6, a lowpressure drop can be ensured past the supply tube 6 while the dosing arrangement 10 hasconditions for supply accurate amounts of exhaust additive 20 into the stream of exhaust gas.

According to further embodiments of the herein described, the distribution device 23 mayhave another shape. As an example, according to some embodiments, the distributiondevice 23 may comprise a receiving surface forming a patterned facial surface. Thispatterned surface may be used to control and optimise the distribution of exhaust additive inthe exhaust stream. As an alternative, or in addition, the exhaust additive distribution device23 may comprise a radial wall, wherein the receiving surface exhaust additive distribution device 23 is an inner face of the radial wall, and wherein the exhaust additive distribution 19 device 23 comprises a distribution surface of an orifice formed in the radial wall, the orificeextending between an inner face of the radial wall and an outer surface of the radial wall.Such a solution resembles current production injector nozzles and thus such a distributiondevice may be obtained by adjustment of current production lines. According to suchembodiments, the distribution device 23 may comprise a mating surface with a supply tube 6, thus helping to avoid undesired leakage of the exhaust additive.

Even though the dosing arrangement 10 according to the illustrated embodiments isconfigured to supply exhaust additive in conjunction with the turbine unit 19 of the turbodevice 30, the supply tube 6 of the dosing arrangement 10 as explained herein may bearranged to supply exhaust additive to another location of an exhaust system of an internalcombustion engine. As an example, the supply tube 6 of the dosing arrangement 10 asexplained herein may be arranged to supply exhaust additive 20 to an exhaust conduitbetween an exhaust manifold 46 and an SCR catalyst 45 of a combustion engine 40. Asanother example, the supply tube 6 of the dosing arrangement 10 as explained herein maybe arranged to supply exhaust additive 20 to an exhaust conduit 47 arranged between a turbine unit 19 of a turbo device 30 and an SCR catalyst 45 of a combustion engine 40. lt is to be understood that the foregoing is illustrative of various example embodiments andthat the invention is defined only by the appended claims. A person skilled in the art willrealize that the example embodiments may be modified, and that different features of theexample embodiments may be combined to create embodiments other than those describedherein, without departing from the scope of the present invention, as defined by the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one ormore stated features, elements, steps, components, or functions but does not preclude thepresence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

1. Claims An airless exhaust additive dosing arrangement (10) configured to supply an exhaustadditive (20) to a stream of exhaust gas of an internal combustion engine (40), wherein the dosing arrangement (10) comprises a supply tube (6) with anopening (8) for the supply of the exhaust additive (20) to the exhaust stream, and wherein the dosing arrangement (10) comprises a flow disturbing structure (11') arranged inside the supply tube (6). The dosing arrangement (10) according to claim 1, wherein the supply tube (6)comprises a section (6') configured to protrude into an exhaust conduit (3a, 5a, 47) ofthe internal combustion engine (40), and wherein the flow disturbing structure (11') is arranged inside the section (6') of the supply tube (6). The dosing arrangement (10) according to claim 1 or 2, wherein the flow disturbing structure (11') is arranged adjacent to the opening (8) of the supply tube (6). The dosing arrangement (10) according to any one of the preceding claims, wherein the opening (8) is an open end of the supply tube (6). The dosing arrangement (10) according to any one of the preceding claims, wherein theflow disturbing structure (11') is at least partially formed by a flow disturbing body (11)arranged inside the supply tube (6). The dosing arrangement (10) according to any one of the preceding claims, wherein theflow disturbing structure (11') is at least partially formed by a wire (11”) arranged inside the supply tube (6). The dosing arrangement (10) according to claim 6, wherein the wire (11”) is formed as a coil-spring. The dosing arrangement (10) according to any one of the preceding claims, wherein theflow disturbing structure (11') is at least partially formed by grooves (12) and/or protrusions (13) provided in an inner surface of the supply tube (6). The dosing arrangement (10) according to any one of the preceding claims, wherein thedosing arrangement (10) comprises a pump (32) configured to pump exhaust additive (20) from an exhaust additive storage unit (34) to the supply tube (6).A turbine outlet assembly (1) for a turbo device (30), wherein the assembly (1)comprises a turbine outlet duct (3) and a dosing arrangement (10) according to any oneof the preceding claims, wherein the supply tube (6) comprises a section (6') with theopening (8) for the supply of the exhaust additive (20), and wherein the section (6') is arranged in the turbine outlet duct (3). The assembly (1) according to claim 10, further comprising a diffuser pipe (5) arranged in the turbine outlet duct (3), and wherein the section (6') is arranged in the diffuser pipe (5). The assembly (1) according to claim 10 or 11, wherein the assembly (1) comprises aturbine unit (19) configured to rotate during operation of a turbo device (30) comprisingthe assembly (1 ), wherein the assembly (1) comprises a distribution device (23)arranged on the turbine unit (19), and wherein the supply tube (6) is arranged to supply an exhaust additive (20) onto the distribution device (23). The assembly (1) according to claim 12, wherein the distribution device (23) is cup- shaped. .A turbo device (30) for an internal combustion engine (40), wherein the turbo device (30) comprises a turbine unit (19) configured to be driven by exhaust gas of the internalcombustion engine (40), and wherein turbo device (30) comprises a turbine outlet assembly (1) according to any one of the claims 10 -An internal combustion engine (40) comprising a turbo device (30) according to claimor a dosing arrangement (10) according to any one of the claims 1 -The internal combustion engine (40) according to claim 15, wherein the internalcombustion engine (40) is a compression ignition engine and wherein the supply tube (6)is configured to supply an aqueous urea solution to exhaust gas flowing through an exhaust conduit (3a, 5a, 47) of the internal combustion engine (40). A vehicle (2) comprising an internal combustion engine (40) according to claim 15 or 16.