SE545036C2

SE545036C2 - Turbine Outlet Assembly for a Turbo Device comprising an exhaust additive dosing unit

Info

Publication number: SE545036C2
Application number: SE2150099A
Authority: SE
Inventors: Anders Gawell; Magnus Lindgren; Viktor Olsson
Original assignee: Scania Cv Ab
Priority date: 2021-01-28
Filing date: 2021-01-28
Publication date: 2023-03-07
Also published as: DE102021134397A1; SE2150099A1

Abstract

A turbine outlet assembly (1) is disclosed for a turbo device (30) of an internal combustion engine (40). The assembly (1) comprises a turbine outlet duct (3), a diffuser pipe (5) arranged in the turbine outlet duct (3), an exhaust additive dosing unit (6) arranged in the diffuser pipe (5), and a wastegate gas outlet (7) connected to a gap (9) between the turbine outlet duct (3) the diffuser pipe (5). The assembly (1) comprises a flow-influencing structure (11') arranged in the gap (9). The flow-influencing structure (11') comprises at least one of a flow restrictor unit (11), a guide vane (12), and a diffuser structure (13). The present disclosure further relates to a turbo device (30) for an internal combustion engine (40), an internal combustion engine (40), and a vehicle (2) comprising an internal combustion engine (40).

Description

TECHNICAL FIELD The present disclosure relates to a turbine outlet assembly for a turbo device of an internal combustion engine, wherein the turbine outlet assembly comprises an exhaust additive dosing unit. The present disclosure further relates to a turbo device 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 fuel efficiency of the engine. One type of turbo device is a turbocharger. A turbocharger comprises a turbine unit and a compressor, wherein the turbine unit is driven by exhaust gas of the engine to power the compressor. The compressor forces air to an air inlet of the engine which allows more fuel to be added and hence higher power output of the engine. A turbocharger 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 turbine unit driven by exhaust gas of the engine. However, instead of powering a compressor, the energy recovered from the exhaust gasses is sent to an output shaft of the engine or is used for another purpose, such as powering an electric generator. The produced electricity can be used to produce motive power to the vehicle in an electric machine or can be used to power one or more other subsystems of the vehicle. A turbo compound is an efficient means of increasing 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 the development of engines using exhaust additives, such as reducing agents for diesel, and/or ethanol, exhaust gases. Reducing agents may comprise an aqueous urea solution and may be used as a consumable in a Selective Catalytic Reduction SCR in order to lower nitrogen oxides NOx concentration in exhaust emissions from the internal combustion engine. A Selective Catalytic Reduction SCR system is a type of engine exhaust catalyst arrangement configured to convert the nitrogen oxides of exhaust gases into diatomic nitrogen and water using a reduction agent. The exhaust additive is usually injected directly upstream of a SCR catalyst.

The use of exhaust additives is associated with some problems and design difficulties. ln order to produce the quantities of ammonia required to reduce substantially all NOx, large quantities of urea solution usually must be injected into the exhaust stream. High temperatures are needed to evaporate the exhaust additive. I\/|oreover, the temperature needed for evaporation depends on the injected mass flow of exhaust additive: the greater the mass flow, the higher the temperature required. Exhaust additives can be corrosive and can damage components of the exhaust system if not sufficiently evaporated. I\/|oreover, the reduction efficiency of the exhaust additive is significantly reduced if the exhaust additive is not fully evaporated.

A further problem with the use of exhaust additives is the requirement for efficient mixing in order to achieve uniform distribution of exhaust additive over the entire surface area of a SCR catalyst substrate. The space available for mixing is limited and the exhaust additive is commonly 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 of the exhaust additive further upstream in the exhaust system, for example in conjunction with a turbine unit arranged in the exhaust system. One such exhaust additive distribution device is described in the document WO 2018080371 A1 _ The device described therein is capable of adding exhaust additive to the exhaust stream in an efficient manner. However, in view of the solution presented in the document WO 2018080371 A1, there is room for improvement regarding vaporization of exhaust additive, mixing of exhaust additive, and probability of contact between exhaust additive and walls of exhaust conduits.

SUMMARY lt 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 a turbine outlet assembly for a turbo device of an internal combustion engine. The assembly comprises a turbine outlet duct, a diffuser pipe arranged in the turbine outlet duct, an exhaust additive dosing unit arranged in the diffuser pipe, and a wastegate gas outlet connected to a gap between the turbine outlet duct and the diffuser pipe. The assembly further comprises a flow- influencing structure arranged in the gap. The flow-influencing structure comprises at least one of a flow restrictor unit, a guide vane, and a diffuser structure.Since the assembly comprises the flow-influencing structure arranged in the gap between the turbine outlet duct and the diffuser pipe, conditions are provided for an increased heat transfer from wastegate gasses to the diffuser pipe. Wastegate gas is hotter than exhaust gas downstream of a turbine unit because the expansion of the exhaust gas in the turbine unit lowers the temperature of the exhaust gas flowing therethrough. An increased transfer of heat from wastegate gasses to the diffuser pipe can thus improve vaporization of exhaust additive added by the exhaust additive dosing unit arranged in the diffuser pipe.

Moreover, since the assembly comprises the flow-influencing structure arranged in the gap between the turbine outlet duct and the diffuser pipe, conditions are provided for an improved mixing of exhaust additive and exhaust gas downstream of the diffuser pipe due to increased turbulence generated by the flow-influencing structure.

Furthermore, since the assembly comprises the flow-influencing structure arranged in the gap between the turbine outlet duct and the diffuser pipe, conditions are provided for generating a boundary layer of wastegate gas preventing exhaust additive from contacting walls of a turbine housing and/or walls of exhaust conduits downstream of the diffuser pipe. ln addition, since the assembly comprises the flow-influencing structure arranged in the gap between the turbine outlet duct and the diffuser pipe, conditions are provided for preventing backflow of exhaust gas and exhaust additive around a trailing edge of the diffuser pipe which further prevents contact between exhaust additive and the turbine outlet duct.

Moreover, since the assembly comprises the flow-influencing structure arranged in the gap between the turbine outlet duct and the diffuser pipe, conditions are provided for removing, and/or preventing formation of, droplets of exhaust additive on a trailing edge of the diffuser pipe which otherwise would risk falling down onto the turbine outlet duct and/or an exhaust conduit arranged downstream of the turbine outlet assembly.

Thus, in summary, due to the features of the turbine outlet duct assembly, conditions are provided for improved vaporization of exhaust additive, improved mixing of exhaust additive and exhaust gas, and a reduced probability of contact between exhaust additive and walls of the turbine outlet duct assembly and/or walls of exhaust conduits downstream of the turbine outlet duct assembly.Accordingly, a turbine outlet duct assembly 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.

Optionaily, the diffuser pipe is configured to conduct exhaust gas in a direction from a first end towards a second end of the diffuser pipe, and wherein the exhaust additive dosing unit is configured to supply an exhaust additive to exhaust gas at a location closer to the first end than the second end of the diffuser pipe. Thereby, the increased heat transfer from the wastegate gas to the diffuser pipe can be utilized along a significant length of the diffuser pipe to improve vaporization of exhaust additive added by the exhaust additive dosing unit.

Optionaily, the assembly comprises a turbine unit configured to rotate during operation of a turbocharger comprising the assembly, and wherein the assembly comprises a distribution device arranged on the turbine unit, and wherein the exhaust additive dosing unit is arranged to supply an exhaust additive 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 distribution device. Due to the large amounts of kinetic energy supplied to the dosed exhaust additive, 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.

Optionaily, the distribution device is cup-shaped. Thereby, the distribution device will function as a rotary cup atomizer. Since a dosing outlet of the exhaust additive dosing unit can be positioned within the cup, and since the geometry of the cup can be optimised to prevent back-flow from a rim of the cup-shaped distribution device, this solution reduces the risk of exhaust additive being unintentionally deposited on turbine surfaces.

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

Optionaily, the exhaust additive distribution device may comprise a radial wall, wherein the receiving surface exhaust additive distribution device is an inner face of the radial wall, and wherein the exhaust additive distribution device comprises a distribution surface of an orifice formed in the radial wall, the orifice extending 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 distribution device may be obtained by adjustment of current production ».-~ i :ån-_lines. According to such embodiments, the distribution device may comprise a mating surface with an exhaust additive dosing unit, thus helping to avoid undesired leakage of the exhaust additive.

Optionaily, the gap encloses more than 70 % of the circumference of the diffuser pipe. Thereby, an efficient transfer of heat from the wastegate gas to the diffuser pipe is ensured. Moreover, a large cross sectional area can be utilized for influencing the flow of wastegate gas flowing through the gap.

Optionaily, the wastegate gas outlet is configured to conduct wastegate gas to the gap in a direction transversal to a centre axis of the diffuser pipe. Thereby, a space efficient connection can be provided between a wastegate gas duct and the wastegate gas outlet.

Optionaily, the flow-influencing structure is configured to divert flow of wastegate gas to distribute the wastegate gas around an outer surface of the diffuser pipe. Thereby, a further increased transfer of heat is provided from the wastegate gas to the diffuser pipe. wastegate gas outlet is arranged on a first side of a plane extending through a centre axis of the diffuser pipe, and wherein the flow-influencing structure provides a greater effective flow cross sectional area at a second side of the plane than at the first side of the plane. Thereby, a more evenly distributed flow of wastegate gas is provided around an outer surface of the diffuser pipe which provides conditions for a further increased transfer of heat from the wastegate gas to the diffuser pipe. I\/|oreover, the diffuser pipe is more evenly heated which provides conditions for a more even and more efficient vaporisation of exhaust additive inside the diffuser pipe.

Optionaily, the flow-influencing structure comprises a flow restrictor unit provided with a number of openings. Thereby, an increased transfer of heat is ensured from the wastegate gas to the diffuser pipe in a simple and efficient manner. I\/|oreover, due to the openings, conditions are provided for generating a boundary layer of wastegate gas preventing exhaust additive from contacting walls of a turbine housing and/or walls of exhaust conduits downstream of the diffuser pipe. ln addition, due to the openings, a more turbulent flow of gas can be generated downstream of the diffuser pipe to improve mixing between exhaust additive and exhaust gas. Furthermore, due to the openings and the accelerated flow therethrough, conditions are provided for removing, and/or preventing formation of, droplets of exhaust additive on a trailing edge of the diffuser pipe which othenivise would risk fallingdown onto the turbine outlet duct and/or an exhaust conduit arranged downstream of the turbine outlet assembly.

Optionally, the flow restrictor unit is ring-shaped and wherein openings of the number of openings are distributed around a circumferential direction of the ring-shaped flow restrictor unit. Thereby, an increased transfer of heat is ensured from the wastegate gas to the diffuser pipe in a simple and cost-efficient manner.

Optionally, the number of openings comprise openings of different sizes. Thereby, conditions are provided for generating a more evenly distributed flow of wastegate gas around an outer surface of the diffuser pipe which provides conditions for a further increased transfer of heat from the wastegate gas to the diffuser pipe and a more evenly heated diffuser pipe. Accordingly, due to these features, conditions are provided for a more even and more efficient vaporisation of exhaust additive inside the diffuser pipe.

Optionally, the diffuser pipe is configured to conduct exhaust gas in a direction from a first end towards a second end of the diffuser pipe, and wherein the flow restrictor unit is arranged adjacent to the second end of the diffuser pipe. Thereby, the flow restrictor unit restricts flow in a region of the second end of the diffuser pipe and increases the pressure inside substantially the entire gap between the turbine outlet duct and the diffuser pipe. Thereby, an efficient transfer of heat from wastegate gasses to the diffuser pipe is ensured. Moreover, conditions are provided for further preventing backflow of exhaust gas and exhaust additive around the second end of the diffuser pipe which further prevents contact between exhaust additive and the turbine outlet duct. Furthermore, conditions are provided for removing, and/or preventing formation of, droplets of exhaust additive on the second end of the diffuser pipe which otherwise would risk falling down onto the turbine outlet duct and/or an exhaust conduit arranged downstream of the turbine outlet assembly.

Optionally, the flow-influencing structure comprises at least one guide vane comprising a pitch angle relative to a direction of a centre axis of the diffuser pipe. Thereby, improved conditions are provided for generating a boundary layer of wastegate gas preventing exhaust additive from contacting walls of a turbine housing and/or walls of exhaust conduits downstream of the diffuser pipe. Moreover, conditions are provided for an improved mixing of exhaust additive and exhaust gas downstream of the diffuser pipe due and an increased heat transfer from wastegate gasses to the diffuser pipe to thereby increase vaporization of exhaust additive inside the diffuser pipe.Optionally, the at least one guide vane is/are configured to provide a cyclone of wastegate gas around a centre axis of the diffuser pipe. Due to the cyclone of wastegate gas around a centre axis of the diffuser pipe, further improved conditions are provided for generating a boundary layer of wastegate gas preventing exhaust additive from contacting walls of a turbine housing and/or walls of exhaust conduits downstream of the diffuser pipe. Moreover, conditions are provided for an improved mixing of exhaust additive and exhaust gas downstream of the diffuser pipe due and an increased heat transfer from wastegate gasses to the diffuser pipe to thereby increase vaporization of exhaust additive inside the diffuser pipe.

Optionally, the flow-influencing structure comprises a number of guide vanes distributed around a circumferential direction of the gap. Thereby, a cyclone of wastegate gas around a centre axis of the diffuser pipe can be generated in a simple and cost-effective manner.

Optionally, the flow-influencing structure comprises a diffuser structure forming a diffuser gap between an inner surface of the diffuser structure and an outer surface of the diffuser pipe. Thereby, a simple and efficient flow-influencing structure is provided capable of increasing transfer of heat from wastegate gasses to the diffuser pipe, capable of improving mixing of exhaust additive and exhaust gas downstream of the diffuser pipe, and reducing the probability of contact between exhaust additive and walls of the turbine outlet duct assembly, and/or walls of exhaust conduits downstream of the turbine outlet duct assembly.

Optionally, the diffuser gap has an increasing width along an intended flow direction through the diffuser gap. Thereby, a diffuser structure is provided capable of reducing the velocity and increasing the static pressure of a wastegate gas passing through the diffuser gap.

According to a second aspect of the invention, the object is achieved by a turbo device for an internal combustion engine, wherein the turbo device comprises a turbine unit configured to be driven by exhaust gas of the internal combustion engine, and wherein the turbo device comprises a turbine outlet assembly according to some embodiments of the present disclosure.

Since the turbo device comprises a turbine outlet assembly according to some embodiments, a turbo device is provided having conditions for improving vaporization of exhaust additive, improving mixing of exhaust additive and exhaust gas, and a reducing probability of contact between exhaust additive and walls of the turbine outlet duct assembly and/or walls of exhaust conduits downstream of the turbine outlet duct assembly.

Accordingly, a turbo device 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.

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

Since the internal combustion engine comprises a turbo device according to some embodiments, an internal combustion engine is provided having conditions for improving vaporization of exhaust additive, improving mixing of exhaust additive and exhaust gas, and a reducing probability of contact between exhaust additive and walls of the turbine outlet duct assembly and/or walls of exhaust conduits downstream of the turbine outlet duct assembly.

Accordingly, 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 the exhaust additive dosing unit is configured to supply an aqueous urea solution to exhaust gas flowing through the diffuser pipe.

According to a fourth aspect of the invention, the object is achieved by a vehicle comprising an internal combustion engine according to some embodiments of the present disclosure.

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 DRAWINGS Various aspects of the invention, including its particular features and advantages, will be readily 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 present disclosure, 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 some embodiments, Fig. 4 illustrates a cross section of a diffuser pipe and a flow-influencing structure according to embodiments illustrated in Fig. 3, Fig. 5 illustrates the flow-influencing structure according to the embodiments illustrated in Fig. 4, Fig. 6 illustrates a side view of a diffuser pipe and a flow-influencing structure according to some further embodiments, Fig. 7 illustrates a front view of the diffuser pipe and the flow-influencing structure according to the embodiments illustrated in Fig. 6, and Fig. 8 illustrates a cross section of a diffuser pipe and a flow-influencing structure according to some further embodiments.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to like elements 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 present disclosure. According to the illustrated embodiments, the vehicle 2 is a truck, i.e. a heavy vehicle. 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 illustrated embodiments, the internal combustion engine 40 is configured to provide motive power to the vehicle 2 via wheels 41 of the vehicle Fig. 2 schematically illustrates the internal combustion engine 40 of the vehicle 2 illustrated in Fig. 1. According to the illustrated embodiments, the internal combustion engine 40 is a diesel 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-ignition device, 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 internal combustion engine 40 is in some places herein referred to as the combustion engine 40, or simply the engine 40. According to some embodiments, the combustion engine 40, as referred 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, the turbo device 30 comprises a turbine unit configured to be driven by exhaust gas of the internal combustion engine 40. According to the illustrated embodiments, the turbo device 30 is a turbocharger, i.e. a charging device configured to compress air to an air inlet 42 of the combustion engine 40. Thus, according to these embodiments, the turbine unit of the turbo device 30 is connected to the compressor. According to further embodiments, the turbo device 30, as referred to herein, may be a turbo compound device wherein the turbine unit is connected 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 filter unit 43 and a charge air cooler 44. The compressor of the turbo device 30 is configured to force air from the air filter unit 43 to the air inlet 42 of the engine 40. The charge air cooler 44 is arranged between the compressor of the turbo device 30 and the air inlet 42 of the combustion engine 40. The charge air cooler 44 is configured to cool the compressed air before the air is conducted to the air inlet 42. ln this manner, the power output and fuel efficiency of the combustion engine 40 can be improved. l\/loreover, according to the illustrated embodiments, the combustion engine 40 comprises a Selective Catalytic Reduction SCR catalyst 45 arranged downstream of the turbine unit of the turbo device Fig. 3 illustrates a cross section of a turbine outlet assembly 1 according to some embodiments. According to the illustrated embodiments, the turbine outlet assembly 1 comprises a turbine unit 19. ln such embodiments, the turbine outlet assembly 1, as referred to herein, may also be referred to as a turbine assembly for a turbo device. The turbine unit 19 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 turbo device in the form of a turbocharger or a turbo device in the form of a turbo compound device. ln other words, the turbo device 30 illustrated in Fig. 2 may comprise a turbine outlet assembly 1 according to the embodiments illustrated in Fig. 3. Therefore, below, simultaneous reference is made to Fig. 2 and Fig. 3 if not indicated othen/vise.The turbine unit 19 is configured to rotate around a rotation axis Ra during operation of a turbo device 30 comprising the turbine out|et assembly 1. ln Fig. 3, the cross section is made in a plane comprising the rotation axis Ra of the turbine unit 19. The turbine unit 19 comprises a turbine 19" and a shaft 19" connected to the turbine 19". According to the illustrated embodiments, the turbine 19" and the shaft 19" are formed by one piece of coherent material. According to further embodiments, the turbine 19" and the shaft 19" may be separate parts wherein the turbine 19" is connected to the shaft 19". ln embodiments in which the turbine out|et assembly 1 forms part of a turbo device 30 in the form of a turbocharger, the shaft 19" of the turbine unit 19 is connected to a compressor, such as a compressor explained with reference to Fig. 2. ln embodiments in which the turbine out|et assembly 1 forms part of a turbo device 30 in the form of a turbo compound device, the shaft 19" of the turbine unit 19 may be connected to an output shaft of a combustion engine 40 or to another shaft or type of device configured to produce useful energy by the rotation of the turbine unit The turbine out|et assembly 1 comprises a turbine housing 51. The turbine unit 19 is arranged 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 f|uidly connected to an exhaust manifold of a combustion engine, such as the exhaust manifold 46 of the combustion engine 40 illustrated in Fig. 2. The flow of exhaust gas from the volute 52 through the turbine 19" causes rotation of the turbine unit 19 around the rotation axis Ra. The turbine out|et assembly 1 further comprises a turbine out|et duct 3 arranged downstream of the turbine unit 19 and a diffuser pipe 5 arranged in the turbine out|et duct 3. The diffuser pipe 5 is arranged in the turbine out|et duct 3 such that a gap 9 is formed between an inner surface 3' of the turbine out|et duct 3 and an outer surface 5' of the diffuser pipe 5. According to the illustrated embodiments, the turbine out|et duct 3 form part of the turbine housing 51 but may also be a separate part attached to the turbine housing 51. However, since the turbine out|et duct 3 form part of the turbine housing 51 according to the illustrated embodiments, 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.

The turbine out|et assembly 1 comprises a wastegate valve 61. ln Fig. 3, the wastegate valve 61 is illustrated in a closed position. According to the illustrated embodiments, the wastegate valve 61 is f|uidly connected to the volute 52. The turbine out|et assembly 1 comprises a wastegate gas out|et 7 connected to the gap 9 between the turbine out|et duct 3 and the diffuser pipe 5. According to the illustrated embodiments, the wastegate gas out|et 7 is configured 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, the wastegate valve 61 closes a fluid connection betvveen the volute 52 and the wastegate gas outlet 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 The wastegate valve 61 is controllable from the closed position to an open position in which the wastegate valve 61 opens a fluid connection between the volute 52 and the wastegate gas outlet 7. Thereby, when the wastegate valve 61 is in the open position, part of the exhaust gas from the volute 52 is bypassing the turbine 19" of the turbine unit 19 and instead flows 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 According to the illustrated embodiments, the wastegate valve 61 is pivotally arranged around a pivot axis Pa between the open and closed position. However, according to further embodiments, the wastegate valve 61 may be arranged to be controlled between the open and closed positions in another manner, such as by a linear displacement. The wastegate valve 61 may be controlled between the open and closed positions by an actuator, such as a pneumatic and/or electric actuator in a conventional manner. As an example, the wastegate valve 61 may be controlled to the open position when it is wanted to limit a rotational speed of 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 As can be seen in Fig. 3, according to the illustrated embodiments, the wastegate valve 61 is arranged inside the turbine housing 51 and the wastegate valve 61 is in direct fluid connection with the volute 52. According to further embodiments, the wastegate valve 61 may not be arranged inside the turbine housing 51 and may be fluidly connected to another portion of an exhaust conduit between an exhaust outlet of a combustion engine and the turbine 19" of the turbine unit Moreover, as can be seen in Fig. 3, the turbine outlet assembly 1 comprises an exhaust additive dosing unit 6 arranged inside the diffuser pipe 5. According to the illustrated embodiments, the exhaust additive dosing unit 6 is formed as a supply tube comprising an open end 8 positioned inside the diffuser pipe 5. l\/loreover, according to the illustrated embodiments, the exhaust additive dosing unit 6 is arranged such that a centre axis Ca of the diffuser pipe 5 extends through the open end 8 of the exhaust additive dosing unit 6. The exhaust additive dosing unit 6 is configured to supply exhaust additive, such as an aqueous urea solution, to exhaust gas flowing through the diffuser pipe 5. The exhaust additive dosingunit 6 is connected to an exhaust additive dosing arrangement 10. The turbine outlet assembly 1, as referred to herein, may comprise at least part of the exhaust additive dosing arrangement According to the illustrated embodiments, the exhaust additive dosing arrangement 10 is an airless exhaust additive dosing arrangement 10 meaning that the exhaust additive dosing arrangement 10 is configured to pump exhaust additive using a pump 32 instead of using compressed air as some other types of exhaust additive dosing arrangements. ln more detail, according to the illustrated embodiments, the exhaust additive dosing arrangement 10 comprises an exhaust additive storage unit 34 configured to accommodate exhaust additive 20 and a pump 32 configured to pump exhaust additive 20 from the exhaust additive storage unit 34 to the exhaust additive dosing unit 6. Moreover, the exhaust additive dosing arrangement 10 may comprise some further components 36 between the pump 32 and the exhaust additive dosing unit 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 embodiments herein, the internal combustion engine 40 is a compression ignition engine and the exhaust additive dosing unit 6 is configured to supply an aqueous urea solution to exhaust gas flowing through the diffuser pipe 5. As indicated in Fig. 2, the combustion engine 40 may comprise a Selective Catalytic Reduction SCR catalyst 45 arranged downstream of the turbo device 30 and thus also downstream of the turbine outlet assembly 1. The SCR catalyst 45 may convert nitrogen oxides of exhaust gases into diatomic nitrogen and water using the exhaust additive 20 added to exhaust gas by the exhaust additive dosing unit According to embodiments herein, the turbine outlet assembly 1 comprises a flow-influencing structure 11" arranged in the gap 9 between the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipe 5. The flow-influencing structure 11" is configured to divert, restrict, and/or change flow velocity of wastegate gas flowing through the gap 9. According to the embodiments illustrated in Fig. 3, the flow-influencing structure 11" comprises a flow restrictor unit 11. As is further explained herein, according to further embodiments, the flow-influencing structure 11" may comprise at least one guide vane or a diffuser structure.

The wastegate gas, i.e. the exhaust gas conducted through the wastegate valve 61 and the wastegate gas outlet 7 into the gap 9, has a higher temperature and pressure than exhaust gas conducted through the turbine 19" of the turbine unit 19 because the expansion of theexhaust gas in the turbine 19" lowers the pressure and temperature of the exhaust gas flowing therethrough. Since the turbine outlet assembly 1 comprises the flow-influencing structure 11" arranged in the gap 9, conditions are provided for an increased heat transfer from wastegate gasses to the diffuser pipe 5. An increased transfer of heat from wastegate gasses to the diffuser pipe 5 improves vaporization of exhaust additive 20 added by the exhaust additive dosing unit 6 arranged in the diffuser pipe 5. According to the illustrated embodiments, the gap 9 encloses substantially the entire circumference of the diffuser pipe 5. According to further embodiments, the gap 9 may enclose more than 70%, or more than 85%, of the circumference of the diffuser pipe 5. Thereby, an efficient transfer of heat from the wastegate gasses to the diffuser pipe 5 can be ensured.

As can be seen in Fig. 3, the diffuser pipe 5 is configured to conduct exhaust gas in a direction d1 from a first end 15 towards a second end 17 of the diffuser pipe 5. According to the illustrated embodiments, the exhaust additive dosing unit 6 is configured to supply an exhaust additive 20 to exhaust gas at a location closer to the first end 15 than the second end 17 of the diffuser pipe 5. Thereby, the increased heat transfer from the wastegate gas to the diffuser pipe 5 can be utilized along a significant length of the diffuser pipe 5 to improve vaporization of exhaust additive 20 added by the exhaust additive dosing unit According to the embodiments illustrated in Fig. 3, the assembly 1 comprises a distribution device 23 arranged on the turbine unit 19, wherein the exhaust additive dosing unit 6 is arranged to supply an exhaust additive 20 onto the distribution 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 illustrated embodiments, the rotational axis Ra of the turbine unit 19 coincides with the centre axis Ca of the diffuser pipe 5. According to the illustrated embodiments, the distribution device 23 form part of the turbine 19" of the turbine unit 19, i.e. the distribution device 23 and the turbine 19" are formed by one piece of coherent material. According to further embodiments, the distribution device 23 may be a separate part attached to the turbine 19' for example by welding and/or by one or more fastening elements.

According to the illustrated embodiments, the distribution device 23 is cup-shaped and the exhaust additive dosing unit 6 protrudes into an open face of the cup-shaped distribution device 23 such that the opening 8 of the exhaust additive dosing unit 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 20 is provided. ln addition, the cup-shape of the distribution device 23 prevents back-flow from the cup rim and reduces the risk of exhaust additive being unintentionally deposited on surfaces of the turbine 19".

According to further embodiments of the herein described, the distribution device 23 may have another shape. As an example, according to some embodiments, the distribution device 23 may comprise a receiving surface forming a patterned facial surface. This patterned surface may be used to control and optimise the distribution of exhaust additive 20 in the exhaust stream. As an alternative, or in addition, the exhaust additive distribution device 23 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 device 23 comprises a distribution surface of an orifice formed in the radial wall, the orifice extending 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 distribution device may be obtained by adjustment of current production lines. According to such embodiments, the distribution device 23 may comprise a mating surface with an exhaust additive dosing unit 6, thus helping to avoid undesired leakage of the exhaust additive.

Fig. 4 illustrates a cross section of a diffuser pipe 5 and a flow-influencing structure 11" according to the embodiments illustrated in Fig. 3. ln Fig. 4, the cross section is made in a plane comprising the centre axis Ca of the diffuser pipe 5. Below, simultaneous reference is made the Fig. 3 and Fig. 4, if not indicated othenNise. As indicated in Fig. 4, the diffuser pipe 5 is configured to conduct exhaust gas in a direction d1 from a first end 15 towards a second end 17 of the diffuser pipe 5. The first end 15 thus faces the turbine unit 19 and is configured to receive exhaust gas therefrom. The second end 17 faces an exhaust conduit 47 and is configured to supply exhaust gas thereto. An example exhaust conduit 47 is illustrated in Fig. 2. I\/|oreover, as is indicated in Fig. 4, the diffuser pipe 5 has an increasing width w1, w2 along the flow direction d1 through the diffuser pipe 5, and consequently also an increasing cross sectional area, along the flow direction d1 through the diffuser pipe 5. ln other words, the diffuser pipe 5 has a greater width w2 and cross sectional area at the second end 17 than at the first end 5. According to the illustrated embodiments, the diffuser pipe has a circular cross section and is frusto-conical. Therefore, according to these embodiments, the diffuser pipe 5 may also be referred to as a diffuser cone.

Fig. 5 illustrates the flow-influencing structure 11" according to the embodiments illustrated in Fig. 4. ln Fig. 5, the flow-influencing structure 11" is illustrated in a viewing direction coinciding with the centre axis Ca of the diffuser pipe 5. According to the illustratedembodiments, the flow-influencing structure 11" comprises a flow restrictor unit 11 provided with a number of openings 25. The flow restrictor unit 11 is ring-shaped and wherein openings 25 of the number of openings 25 are distributed around a circumferential direction cd of the ring-shaped flow restrictor unit As is best seen in Fig. 3 and Fig. 4, the flow restrictor unit 11 according to the i||ustrated embodiments is arranged adjacent to the second end 17 of the diffuser pipe 5. ln this manner, the flow restrictor unit 11 restricts flow in a region of the second end 17 of the diffuser pipe 5 and increases the pressure inside substantially the entire gap 9 between the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipe Thereby, an efficient transfer of heat from wastegate gasses to the diffuser pipe 5 is ensured. l\/loreover, when the wastegate gas passes the openings 25 of the flow restrictor unit 11 indicated in Fig. 5, the flow is accelerated which causes a high flow velocity of wastegate gasses through the openings 25. The openings 25 of the flow restrictor unit 11 thus functions as nozzles. Therefore, the openings 25, as referred to herein, may also be referred to as nozzles. The high flow velocity of wastegate gasses obtained by the flow restrictor unit 11 can reduce the occurrence of contact between exhaust additive added by the exhaust additive dosing unit 6 and exhaust conduits downstream of the turbine outlet assembly 1 by forming a boundary layer of wastegate gas protecting walls of such exhaust conduits.

The following is explained with simultaneous reference to Fig. 3 and Fig. 5. The flow velocity of wastegate gasses generated by the flow restrictor unit 11 can reduce the occurrence of contact between exhaust additive added by the exhaust additive dosing unit 6 and exhaust conduits downstream of the turbine outlet assembly 1 by removing, and/or prevent formation of, droplets of exhaust additive on a trailing edge 17" of the diffuser pipe 5 which otherwise would risk falling down onto such exhaust conduits. As can be seen when comparing Fig. 3 and Fig. 5, the flow restrictor unit 11 according to the i||ustrated embodiments comprises one opening 25 facing the lowermost part of the trailing edge 17" of the diffuser pipe 5 when the assembly is mounted in an intended orientation relative to a local gravity field. Thereby, droplets of exhaust additive on a trailing edge 17" of the diffuser pipe 5 can be further prevented or removed.

As indicated in Fig. 3, the wastegate gas outlet 7 is arranged on a first side S1 of a plane P extending through a centre axis Ca of the diffuser pipe 5. The plane P is perpendicular to the cross section of Fig. 3 and comprises a normal pointing towards the wastegate gas outlet 7. The plane P and the first and second sides S1, S2 thereof are also indicated in Fig. 5. The second side S2 of the plane P is opposite to the first side S1 of the plane P. According to theembodiments illustrated in Fig. 3 - Fig. 5, the flow-influencing structure 11" provides a greater effective flow cross sectional area at the second side S2 of the plane P than at the first side S1 of the plane P. ln this manner, the flow-influencing structure 11" will divert flow of wastegate gas to distribute the wastegate gas around the outer surface 5" of the diffuser pipe 5. Thereby, a more evenly distributed flow of wastegate gas is provided around an outer surface 5" of the diffuser pipe 5 which provides conditions for a further increased transfer of heat from the wastegate gas to the diffuser pipe 5. I\/|oreover, the diffuser pipe 5 is more evenly heated which provides conditions for a more even and more efficient vaporisation of exhaust additive inside the diffuser pipe As is best seen in Fig. 5, according to the illustrated embodiments, the number of openings 25 comprise openings 25 of different sizes. According to the embodiments illustrated in Fig. 5, the flow-influencing structure 11" provides a greater effective flow cross sectional area at a second side S2 of the plane P than at the first side S1 of the plane P by comprising openings 25 having larger effective cross sections at the second side S2 and a higher number of openings 25 at the second side S2 as compared to the first side S1. According to further embodiments, the flow-influencing structure 11" may comprise only one of these alternatives, i.e. one of openings 25 having larger effective cross sections at the second side S2 and a higher number of openings 25 at the second side S2 as compared to the first side S1. Moreover, according to some embodiments, the flow-influencing structure 11" may comprise openings 25 only at the second side S2 and no openings at the first side S1. According to the illustrated embodiments, the flow-influencing structure 11" provides approximately 6.5 greater effective flow cross sectional area at a second side S2 of the plane P than at the first side S1 of the plane P. According to further embodiments, the flow-influencing structure 11" may provide an effective flow cross sectional area at a second side S2 of the plane P being within the range of 1.2 - 15 times, or within the range of 3 - 10 times, the effective flow cross sectional area at the first side S1 of the plane P.

According to the embodiments illustrated in Fig. 3 - Fig. 4, the flow restrictor unit 11 is ring shaped and is a separate component attached to an interface between the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipe 5. According to further embodiments, the flow restrictor unit 11 may be integral with at least one of the turbine outlet duct 3 and the diffuser pipe 5. I\/|oreover, the flow restrictor unit 11, as referred to herein, may be configured to restrict flow of wastegate gas in another manner, and may comprise another type of structure than a body provided with a number of openings 25. As an example, the flow-influencing structure 11" may form a flow restrictor unit by modifications of at least one of the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipeAlso in such embodiments, the flow-influencing structure 11" may provide a greater effective flow cross sectional area at the second side S2 of the plane P than at the first side S1 of the plane P to distribute the wastegate gas around the outer surface 5" of the diffuser pipe Fig. 6 iliustrates a side view of a diffuser pipe 5 and a flow-influencing structure 11" according to some further embodiments. The diffuser pipe 5 and the flow-influencing structure 11" may replace the diffuser pipe 5 and the flow-influencing structure 11" explained with reference to Fig. 3 - Fig. 5. That is, the turbine outlet assembly 1 explained with reference to Fig. 3 - Fig. 5 may comprise a diffuser pipe 5 and a flow-influencing structure 11" according to the embodiments illustrated in Fig. 6. The diffuser pipe 5 illustrated in Fig. 6 comprises the same features, functions, and dimensions as the diffuser pipe 5 explained with reference to Fig. 3 - Fig. 5. ln Fig. 6, a centre axis Ca of the diffuser pipe 5 is indicated. The diffuser pipe 5 is illustrated such that the centre axis Ca is perpendicular to a viewing direction of Fig. 6. According to the embodiments illustrated in Fig. 6, the flow-influencing structure 11" comprises a number of guide vanes 12 each comprising a pitch angle relative to a direction d1 of the centre axis Ca of the diffuser pipe Fig. 7 iliustrates a front view of the diffuser pipe 5 and the flow-influencing structure 11" according to the embodiments illustrated in Fig. 6. ln other words, in Fig. 7, the diffuser pipe 5 and the flow-influencing structure 11" are illustrated such that the centre axis Ca of the diffuser pipe 5 coincides with the viewing direction of Fig. 7. As best seen in Fig. 7, the flow- influencing structure 11" according to the illustrated embodiments comprises eight guide vanes 12. According to further embodiments, the flow-influencing structure 11" may comprise another number of guide vanes 12, such as a number between one and tvventy or a number between three and fifteen. According to the illustrated embodiments, each of the guide vanes 12 has a pitch angle angled in the same direction relative to the centre axis Ca of the diffuser pipe 5. Moreover, each of the guide vanes 12 has a wing-profile relative to the centre axis Ca of the diffuser pipe 5. The guide vanes 12 are positioned in the gap 9 between the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipe 5 when the diffuser pipe 5 and the flow-influencing structure 11" are attached to the turbine outlet assembly 1 illustrated in Fig. 3. Therefore, the gap 9 is also indicated in Fig.

According to the illustrated embodiments, the guide vanes 12 are evenly distributed around a circumferential direction cd of the gap 9. As understood from the above described, according to the illustrated embodiments, the guide vanes 12 are configured to provide a cyclone/vortex of wastegate gas around a centre axis Ca of the diffuser pipe 5. ln this manner, an efficient transfer of heat is provided from wastegate gas to the diffuser pipe 5. l\/loreover, due to theguide vanes 12, the flow-influencing structure 11' will divert flow of wastegate gas to distribute the wastegate gas around the outer surface 5' of the diffuser pipe 5. Thereby, a more evenly distributed flow of wastegate gas is provided around an outer surface 5' of the diffuser pipe 5 which provides conditions for a further increased transfer of heat from the wastegate gas to the diffuser pipe 5. Moreover, the diffuser pipe 5 is more evenly heated which provides conditions for a more even and more efficient vaporisation of exhaust additive inside the diffuser pipe ln the following, simultaneous reference is made to Fig. 3, Fig. 6, and Fig. 7. Due to the guide vanes 12, a rotating cyclone of wastegate gas is provided downstream of the turbine out|et assembly 1 which forms rotating a boundary layer of wastegate gas downstream of the turbine out|et assembly 1 protecting walls of exhaust conduits from contact with exhaust additive added by the exhaust additive dosing unit 6 inside the diffuser pipe 5. I\/|oreover, due to the guide vanes 12, the rotating cyclone of wastegate gas generated thereof can remove, and/or prevent formation of, droplets of exhaust additive on a trailing edge 17' of the diffuser pipe 5 which otherwise would risk falling down onto such exhaust conduits.

According to the embodiments illustrated in Fig. 6 - Fig. 7, the guide vanes 12 are part of the diffuser pipe 5. ln other words, according to the illustrated embodiments, the guide vanes 12 and the diffuser pipe 5 are provided in one piece of coherent material. According to further embodiments, the guide vanes 12 may be part of the turbine out|et duct 3. As a further alternative, the guide vanes 12 may be separate components, possibly connected to each other via a ring-shaped body, wherein the guide vanes 12 are attached in the gap 9 between the inner surface 3' of the turbine out|et duct 3 and the outer surface 5' of the diffuser pipe Fig. 8 illustrates a cross section of a diffuser pipe 5 and a flow-influencing structure 11' according to some further embodiments. ln Fig. 8, the diffuser pipe 5 and the flow-influencing structure 11' are illustrated as arranged in a turbine housing 51. The turbine housing 51, the diffuser pipe 5 and the flow-influencing structure 11' may replace the turbine housing 51, the diffuser pipe 5 and the flow-influencing structure 11' of the turbine out|et assembly 1 according to the embodiments illustrated in Fig. 3. ln other words, the turbine out|et assembly 1 explained with reference to Fig. 3 may comprise a turbine housing 51, a diffuser pipe 5 and a flow-influencing structure 11' according to the embodiments illustrated in Fig. 8. The turbine housing 51 and the diffuser pipe 5 illustrated in Fig. 8 may comprise the same features, functions, and dimensions as the turbine housing 51 and the diffuser pipe 5 explained with reference to Fig. 3. Therefore, below, simultaneous reference is made to Fig. 3 and Fig. 8 if not indicated otherwise. ln Fig. 8, a wastegate gas out|et 7 is schematically indicated. The wastegate gas outlet 7 is connected to a wastegate valve 61 as explained with reference to Fig. 3 and to the gap 9 between the inner surface 3' of the turbine outlet duct 3 and the outer surface 5' of the diffuser pipe According to the embodiments illustrated in Fig. 8, the flow-influencing structure 11' comprises a diffuser structure 13 forming a diffuser gap 9' between the inner surface 13' of the diffuser structure 13 and the outer surface 5' of the diffuser pipe 5. The diffuser gap 9' has an increasing width w3, w4 and consequently also an increasing effective cross sectional area along an intended flow direction d3 through the diffuser gap 9'.

The diffuser structure 13 increases the pressure of wastegate gas flowing through the diffuser gap 9' and thereby provides an efficient transfer of heat from wastegate gas to the diffuser pipe 5. Moreover, the diffuser structure 13 diverts flow of wastegate gas to distribute the wastegate gas around the outer surface 5' of the diffuser pipe 5. Thereby, a more evenly distributed flow of wastegate gas is provided around an outer surface 5' of the diffuser pipe 5 which provides conditions for a further increased transfer of heat from the wastegate gas to the diffuser pipe 5. l\/loreover, the diffuser pipe 5 is more evenly heated which provides conditions for a more even and more efficient vaporisation of exhaust additive inside the diffuser pipe Furthermore, according to some embodiments, the diffuser gap 9' has a greater width w3, w4 and effective cross sectional area at a second side S2 of a plane P extending through a centre axis Ca of the diffuser pipe 5 than at a first side S1 of the plane P, wherein the plane P, and the first and second sides S1, S2 thereof are defined in the same manner as explained with reference to Fig. 3 and Fig. 5 above. Thereby, the diffuser structure 13 will divert flow of wastegate gas in an improved manner to distribute the wastegate gas around the outer surface 5' of the diffuser pipe 5 and more evenly distribute flow of wastegate gas around the outer surface 5' of the diffuser pipe Furthermore, due to the diffuser structure 13, a boundary layer of wastegate gas is formed downstream of the turbine outlet assembly 1 protecting walls of exhaust conduits from contact with exhaust additive added by the exhaust additive dosing unit 6 inside the diffuser pipe 5. Moreover, due to the diffuser structure 13, the flow of wastegate gas therefrom can remove, and/or prevent formation of, droplets of exhaust additive on a trailing edge 17' of the diffuser pipe 5 which otherwise would risk falling down onto such exhaust conduits.According to the embodiments illustrated in Fig. 8, the diffuser structure 13 is part of the turbine outlet duct 3. ln other words, according to the illustrated embodiments, the diffuser structure 13 and the turbine outlet duct 3 are provided in one piece of coherent material. According to further embodiments, the diffuser structure 13 may be part of the diffuser pipe 5. As a further alternative, the diffuser structure 13 may be a separate component attached in the gap 9 between the inner surface 3" of the turbine outlet duct 3 and the outer surface 5" of the diffuser pipe The embodiments herein may be combined. That is, the turbine outlet assembly 1 as explained herein may comprise a combination of two or more flow-influencing structures 11" explained herein. As an example, the turbine outlet assembly 1 may comprise a combination of the flow-influencing structure 11" explained with reference to Fig. 6 and Fig. 7 and the flow- influencing structure 11" explained with reference to Fig. 8. As another example, the turbine outlet assembly 1 may comprise a combination of the flow-influencing structure 11" explained with reference to Fig. 3 - Fig. 5 and the flow-influencing structure 11" explained with reference to Fig.

Since the turbine outlet assembly 1 according to the illustrated embodiments form part of a turbine housing 51, the turbine outlet assembly 1 as referred to herein may also be referred to as a turbine housing or a turbine housing assembly. Therefore, throughout this disclosure, the wording turbine outlet assembly 1 may be replaced by the wording "turbine housing "or the wording "turbine housing assembly". lt is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims.

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

Claims

1. CLAIMS

2. A turbine outlet assembly (1) for a turbo device (30) of an internal combustion engine (40), wherein the assembly (1) comprises: - a turbine outlet duct (3), - a diffuser pipe (5) arranged in the turbine outlet duct (3), - an exhaust additive dosing unit (6) arranged in the diffuser pipe (5), and - a wastegate gas outlet (7) connected to a gap (9) between the turbine outlet duct (3) and the diffuser pipe (5), characterized in that the assembly (1) further comprises a flow-influencing structure (11”) arranged in the gap (9), wherein the flow-influencing structure (11') comprises at least one of a flow restrictor unit (11), a guide vane (12), and a diffuser structure (13), and wherein the wastegate gas outlet (7) is arranged on a first side (S1) of a plane (P) extending through a centre axis (Ca) of the diffuser pipe (5), and wherein the flow-influencing structure (11') provides a greater effective flow cross sectional area at a second side (S2) of the plane (P) than at the first side (S1) of the plane (P).

3. The assembly (1) according to claim 1, wherein the diffuser pipe (5) is configured to conduct exhaust gas in a direction (d1) from a first end (15) towards a second end (17) of the diffuser pipe (5), and wherein the exhaust additive dosing unit (6) is configured to supply an exhaust additive to exhaust gas at a location closer to the first end (15) than the second end (17) of the diffuser pipe (5).

4. The assembly (1) according to claim 1 or 2, wherein the assembly (1) comprises a turbine unit (19) configured to rotate during operation of a turbocharger (30) comprising the assembly (1 ), and wherein the assembly (1) comprises a distribution device (23) arranged on the turbine unit (19), and wherein the exhaust additive dosing unit (6) is arranged to supply an exhaust additive onto the distribution device (23).

5. The assembly (1) according to claim 3, wherein the distribution device (23) is cup- shaped.

6. The assembly (1) according to any one of the preceding claims, wherein the gap (9) encloses more than 70% of the circumference of the diffuser pipe (5).The assembly (1) according to any one of the preceding claims, wherein the flow- influencing structure (11') is configured to divert flow of wastegate gas to distribute the wastegate gas around an outer surface (5”) of the diffuser pipe (5).

7. The assembly (1) according to any one of the preceding claims, wherein the flow- influencing structure (11') comprises a flow restrictor unit (11) provided with a number of openings (25).

8. The assembly (1) according to claims 7, wherein the flow restrictor unit (11) is ring- shaped and wherein openings (25) of the number of openings (25) are distributed around a circumferential direction (cd) of the ring-shaped flow restrictor unit (11).

9. The assembly (1) according to claims 7 or 8, wherein the number of openings (25) comprise openings (25) of different sizes.

10. The assembly (1) according to any one of the claims 7 - 9, wherein the diffuser pipe (5) is configured to conduct exhaust gas in a direction (d1) from a first end (15) towards a second end (17) of the diffuser pipe (5), and wherein the flow restrictor unit (11) is arranged adjacent to the second end (17) of the diffuser pipe (5).

11. The assembly (1) according to any one of the preceding claims, wherein the flow- influencing structure (11') comprises at least one guide vane (12) comprising a pitch angle relative to a direction (d1) of a centre axis (Ca) of the diffuser pipe (5).

12. The assembly (1) according to claim 11, wherein the at least one guide vane (12) is/are configured to provide a cyclone of wastegate gas around a centre axis (Ca) of the diffuser pipe (5).

13. The assembly (1) according to any one of the preceding claims, wherein the flow- influencing structure (11') comprises a diffuser structure (13) forming a diffuser gap (9') between an inner surface (13”) of the diffuser structure (13) and an outer surface (5') of the diffuser pipe (5).

14. 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 internal combustion engine (40), and wherein the turbo device (30) comprises a turbine outlet assembly (1) according to any one of the preceding claims.

15. An internal combustion engine (40) comprising a turbo device (30) according to claim

16. The internal combustion engine (40) according to claim 15, wherein the internal combustion engine (40) is a compression ignition engine and wherein the exhaust additive dosing unit (6) is configured to supply an aqueous urea solution to exhaust gas flowing through the diffuser pipe (5).

17. A vehicle (2) comprising an internal combustion engine (40) according to claim 15 or 16.