DE102015104591A1 - Exhaust duct of an internal combustion engine, in particular with an exhaust gas turbocharger, and internal combustion engine with such an exhaust duct - Google Patents

Abstract

The invention relates to an exhaust passage of an internal combustion engine, in particular a reciprocating internal combustion engine with turbocharger, and an internal combustion engine with such an exhaust passage. The invention has for its object to provide an exhaust passage (18) of an internal combustion engine (10) and an internal combustion engine (10) are available, which allow efficient cooling of the exhaust gas of the internal combustion engine (10) and thereby the use of cost-effective materials in the field of flow Allow components downstream of such an internal combustion engine (10). In an exhaust gas duct (18) according to the invention of an internal combustion engine (10) having at least one coolant channel (38) for reducing the temperature of the exhaust gas of the internal combustion engine (10) flowing through the exhaust duct (18), at least one of the cross sections is at least in a partial region of the exhaust gas duct (18) the cooling passage (34) is formed, which is in operative connection to the at least one coolant channel (38).

Description

The invention relates to an exhaust passage of an internal combustion engine, in particular a reciprocating internal combustion engine with exhaust gas turbocharger, and an internal combustion engine with such an exhaust passage.

Particularly in spark-ignited internal combustion engines with turbocharger, the exhaust gas temperature, especially in the range of rated power, reaches very high values. This leads to a high stress on the flow-leading components, such. B. the exhaust passage and a downstream of the engine arranged turbine of an exhaust gas turbocharger. In individual cases, high-temperature-resistant materials must be used for individual elements of the flow-carrying components due to the high temperature stress, which in turn are associated with high costs.

From practice it is known to reduce the exhaust gas temperature by a mixture enrichment (that is, by enrichment) of the fuel-air mixture in the combustion chamber of the internal combustion engine. However, this is undesirable both because of the resulting increased fuel consumption and due to the associated increased exhaust emissions.

Out DE 10 2010 023 054 A1 is an internal combustion engine with a so-called integrated exhaust duct known, ie with an exhaust duct, which is at least partially formed in the cylinder head of the internal combustion engine. A coolant strip of the internal combustion engine may be connected in this internal combustion engine to a circuit for cooling the integrated exhaust gas channel. The document gives no information as to how the cooling of the integrated exhaust duct should be designed in detail.

Out WO 2009/019153 A2 a turbocharger for an internal combustion engine is known, which is provided with a combined cooling device for cooling the turbocharger housing by means of cooling water of a cooling water circuit of the internal combustion engine. The cooling takes place with the aid of cooling water lines, which are arc-shaped and partially surround the exhaust duct of the internal combustion engine on the outside.

The invention has for its object to provide an exhaust passage of an internal combustion engine and an internal combustion engine available that allow efficient cooling of the exhaust gas of the internal combustion engine, in particular before entering a downstream of the engine arranged exhaust gas turbocharger, and thereby the use of low cost materials in the field allow flow leading components downstream of such an internal combustion engine.

The object is achieved according to the invention with the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

In an exhaust gas duct according to the invention of an internal combustion engine having at least one coolant channel for reducing the temperature of the exhaust gas flowing through the exhaust gas duct of the internal combustion engine at least in a partial region of the exhaust duct is formed at least one cooling structure which changes the cross section of the exhaust duct, which is in operative connection with the at least one coolant duct. In particular, liquid and gaseous media can be used as the coolant. It is particularly advantageous for reasons of cost, if water is used as the coolant. It is also advantageous if a coolant is used as coolant, which is at the same time coolant of at least one further cooling circuit, in particular of a cooling circuit of an internal combustion engine. By operative connection is meant that the coolant is spatially bypassed so close to the exhaust duct that heat from the exhaust gas flowing through the exhaust gas is at least indirectly introduced into the coolant and discharged via this, so that the coolant channel at least indirectly and demonstrably to a reduction in the temperature of the the exhaust gas channel flowing exhaust gas leads. For this purpose, the coolant channel can be arranged within, directly or indirectly adjacent to the cooling structure. Immediately adjacent coolant channels are called, which are directly adjacent to the cooling structure. In the case of indirectly adjacent coolant channels, at least one further element is arranged between the cooling structure and the coolant channel, for example a material web of a cylinder head of the internal combustion engine. Above all, an exhaust gas duct according to the invention has the advantage that the temperature of the exhaust gas of an internal combustion engine downstream of the internal combustion engine can be reduced and the internal combustion engine downstream elements are then subjected to a lower temperature load. As a result, in particular in such internal combustion engines which produce high exhaust gas temperatures, downstream elements can be provided with less expensive and less heat-resistant materials, whereby the manufacturing costs of the internal combustion engine itself or of the downstream elements of the internal combustion engine can be reduced.

In a practical embodiment of an exhaust gas duct according to the invention, at least one cooling rib, which projects into the cross section of the exhaust gas duct, is formed as the cooling structure. This is In particular, it is meant that with continuous continuation of the cross section from the region immediately upstream of the cooling structure to the region immediately downstream of the cooling structure, the cross section is narrowed by the projecting into the exhaust passage cooling rib over a certain length. This does not necessarily mean that the cross section of the exhaust gas duct in the region of the cooling structure is reduced. It can also be formed in the longitudinal section of the exhaust passage with the cooling structure, a change in the outer contour of the cross section such that the resulting, available for the flow of exhaust gas cross-section of the exhaust passage in the region immediately in front of the cooling structure, in the longitudinal section with the Cooling structure and / or in the area behind the cooling structure has a constant size or tapers or widened to the same extent. In order to achieve an effective across the cooling structure across effective cross-sectional area, which is desirable to avoid pressure losses, a constriction caused by the cooling structure should be compensated, for example by the outer walls of the exhaust duct are widened in the respective lengths, so that the flow through the Exhaust gas available total cross-sectional area is the same size as in a lying upstream and / or downstream of the cooling structure area (in particular without a corresponding cooling structure) despite a cooling structure formed within the cross-section. At a minimum, the deviation for the cross-sectional area through which exhaust gas flows should be not more than 30 percent in the length portion with the cooling structure compared to an immediately upstream and / or downstream portion, preferably not more than 20 percent, and more preferably not more than 15 percent.

If a plurality of cooling structures are formed within a common longitudinal section of the exhaust passage in an exhaust passage according to the invention and projecting from the outside in the cross section of the exhaust passage, a particularly advantageous cooling effect can be achieved, especially if the cooling structure has a large cooling surface within the exhaust passage of the exhaust passage, the Flow through the exhaust passage with exhaust gas has direct contact with the exhaust gas. In addition, by forming a plurality of inwardly projecting cooling structures or by the formation of - viewed in the longitudinal direction of the exhaust passage - one or more projections projecting to the inside of the exhaust duct targeted turbulence or increased turbulence of the exhaust gas flow can be generated, whereby the heat dissipation is further improved ,

In a further practical embodiment of an exhaust gas duct according to the invention, the exhaust duct is divided into at least two subchannels, at least in a partial region of its length (that is, in a certain length section) by at least one cooling structure designed as a cooling rib. With such a design, a high heat dissipation can also be achieved. The reason for this is that even in this case, the cooling structure has a large, heat-dissipating surface insofar as the cooling structure at the same time forms the inside boundary wall of both partial channels of the exhaust gas duct. In addition, by dividing it into two subchannels, enhanced turbulence, i. H. a turbulence of the exhaust gas, causes, which further promotes heat dissipation.

In a further practical embodiment of an exhaust gas duct according to the invention, the at least one coolant channel is formed at least partially within the cooling structure, i. H. the coolant channel runs where, if no cooling structure would protrude into the cross section, the exhaust gas would flow. In this regard, reference is made in particular to the possibility that a coolant channel may be arranged centrally in an exhaust gas duct over part of its length, so that exhaust gas flows around it over its entire circumference. In this case, the partial region, in which the coolant channel is arranged completely within the exhaust gas channel, completely flows around exhaust gas and thus enables a particularly efficient use of the coolant and a high heat dissipation.

In principle, it is preferable to arrange a cooling structure in an exhaust gas duct according to the invention such that the cross section of the exhaust gas duct does not narrow or narrow the cross section of the exhaust gas duct to a small percentage (eg at most 20 percent or at most 10 percent) in order to avoid pressure fluctuations and related problems To avoid losses due to a cross-sectional change. In that regard, it is preferred if the cross section of the exhaust gas duct immediately upstream of the at least one structure, in the region of the at least one cooling structure and immediately downstream of the at least one cooling structure has a maximum deviation of 30 percent with respect to the smallest flow cross section in the region of the cooling structure. Deviations of at most 10 percent are particularly preferred. Further preferred is a design of the exhaust gas duct, in which no deviation of the size of the cross section is realized in the region of the at least one cooling structure.

The invention also relates to an internal combustion engine having an exhaust duct as described above, in which the exhaust duct is at least partially formed as an integrated exhaust duct and the at least one cooling structure in the Cylinder head of the internal combustion engine is formed. Such a design is used in particular in compact internal combustion engines, in which an increased heat dissipation within the integrated exhaust duct is of particular use, in particular downstream of the cylinder head and thus downstream of the at least one cooling fin an exhaust gas turbocharger is arranged. As already mentioned in the introduction to the description, in some cases very high-priced and temperature-resistant materials must be used for exhaust-gas turbochargers and / or exhaust-gas ducts which are used in internal combustion engines with integrated exhaust-gas duct and downstream exhaust-gas turbocharger. The inventive design of an internal combustion engine, the temperature of the exhaust gas can be effectively reduced before entering a turbine of an exhaust gas turbocharger, so that the exhaust duct itself or individual elements of an exhaust gas turbocharger can be formed with less temperature-resistant and less expensive available materials.

In a further practical embodiment of an internal combustion engine according to the invention, an intermediate element with a cooling device is formed between the cylinder head of the internal combustion engine and the exhaust-gas turbocharger. By an intermediate element is meant a separately manufactured component which is arranged between a cylinder head and an input side of an exhaust gas turbocharger (or a further intermediate element in front of an exhaust gas turbocharger or an exhaust aftertreatment system) to exhaust gas from the cylinder head into the exhaust gas turbocharger and / or to initiate an exhaust aftertreatment system. The intermediate element can likewise have a cooling structure as described above and / or at least one coolant channel for cooling (only) the outer walls of the exhaust gas channel formed in the intermediate element. By means of such intermediate elements, a particularly effective cooling can take place in engines which, due to the requirements of the package, allow a further downstream arrangement of the exhaust-gas turbocharger in order, if necessary, to arrange an intermediate element. The intermediate element can then be produced as a separate component and can be used modularly in internal combustion engines of different power levels, if necessary with or without a cooling device. Thus, in internal combustion engines, which are identical to other internal combustion engines, but have increased performance (for example, by higher charge), if necessary, a matching, separate intermediate element can be installed. Thus, the manufacturing costs for various types of internal combustion engines can be minimized and the heat dissipation optimized for the respective type of internal combustion engine. It is particularly preferred if the intermediate element is operatively connected to the said coolant channel or another coolant channel of the internal combustion engine, so that an already existing cooling circuit is extended by a further cooling circuit leading through the intermediate element. In this case, the cooling of the intermediate element can be realized in a particularly simple and cost-effective manner.

Further practical embodiments and advantages of the invention are described below in conjunction with the drawings. Show it:

1 a schematic representation of an internal combustion engine with an inventive integrated into the cylinder head exhaust passage and a downstream of the engine arranged exhaust gas turbocharger,

2 a representation of the in 1 marked with II area in a longitudinal section,

3 the in 2 marked with III area in an enlarged view,

4 a sectional view (cross section) along the line IV-IV in 3 .

5 a sectional view (longitudinal section) along the line VV in 3 .

6 a sectional view (cross section) according to the line VI-VI in 3 .

7 a further embodiment of an exhaust gas duct according to the invention in cross-section,

8th a further embodiment of an exhaust gas duct according to the invention in cross-section,

9 a further embodiment of an exhaust gas duct according to the invention in a cross section and

10 a further embodiment of an exhaust gas passage according to the invention in cross section.

1 shows an internal combustion engine according to the invention 10 with a total of four cylinders shown schematically 12 and from the cylinders 12 leading away exhaust ducts 14 located at a confluence point 16 to a common (collecting) exhaust duct 18 be merged. The estuary 16 is located within the cylinder head shown schematically 20 , For this reason, the exhaust duct 18 also referred to as "integrated exhaust duct". On the cylinder head 20 flanged is an intermediate element 22 that to the turbine 24 an exhaust gas turbocharger 26 leads. The turbocharger 26 also includes a compressor 28 , As in 1 It can be seen that the exhaust gas takes place via the turbine 24 also, if necessary, via a bypass serving as a wastegate 30 at the turbine 24 the exhaust gas turbocharger 26 be led past. Downstream of the turbine 24 is an exhaust aftertreatment system 32 (For example, in the form of a three-way catalyst) arranged, which is shown only schematically.

In 2 , which is the lower part of the cylinder head 20 as well as the subsequent intermediate element 22 shows is already schematically one inside the exhaust duct 18 arranged cooling structure 34 represented by dashed lines.

In the 3 - 10 are various concrete embodiments of such cooling structures 34 shown in different views. Such cooling structures 34 In particular, as described in connection with the drawings in one in the cylinder head 20 integrated exhaust duct 18 to get integrated. However, you can also do it downstream of a cylinder head 20 , in particular in an intermediate element 22 that between a cylinder head 20 and a turbine 24 an exhaust gas turbocharger 26 is arranged to be formed.

In the 3 - 6 is an inventive exhaust passage 14 with a first embodiment of a cooling structure 34 shown, with the geometric design of the cooling structure 34 in particular from the sectional views according to the section lines IV-IV, VV and VI-VI becomes clear.

The cooling structure 34 is in the in the 3 - 6 shown embodiment as a over the length l of the exhaust passage 18 extending cooling fin 36 formed, which, in particular from the 4 and 6 it can be seen over the entire width B of the exhaust duct 18 extends. From the 4 and 6 is also apparent that the exhaust passage 18 in the region of length l through the cooling fin 36 in an upper sub-channel 18a and a lower subchannel 18b is divided. Like from the 4 and 5 it can be seen, is the cooling fin 36 over the entire width B of the exhaust duct 18 from a coolant channel 38 interspersed.

Out 5 It can also be seen that the coolant channel 38 in the embodiment shown laterally adjacent to the exhaust duct 18 also in front of the 3 Continued with l length section is continued in the form of an inlet and a drain. In the 6 recognizable areas (inlet and outlet) in front of the length section 1 of the coolant channel 38 connect that through the cooling fin 36 extending coolant channel 38 with a cooling circuit, not shown in the figures, for example with a cylinder head 20 and / or the entire internal combustion engine 10 cooling cooling circuit.

7 shows an exhaust duct 18 with a further embodiment of a cooling structure 34 in the form of an outer wall 40 the exhaust duct 18 in the exhaust duct 18 protruding cooling fin 36 , 7 shows the exhaust duct 18 in a cross-section analogous to that in FIG 3 Section marked IV-IV section. The cooling fin 36 extends over a length l of the exhaust passage 18 in the in 7 in cross-section manner, wherein the cooling fin 36 along with a section of the outer wall 40 the exhaust duct 18 a coolant channel 38 forms, which is traversed by a - in particular gaseous or liquid - cooling fluid (shown dotted). In 7 not shown is one for the flow through the coolant channel 38 required inlet and outlet in the coolant channel 38 , An inlet can, for example, at the beginning of the length section l, over which the cooling fin 36 extends, be provided, and a drain in the end region of extending over the longitudinal portion l of the cooling fin 36 ,

Analogous to 7 show the 8th - 10 further embodiments of cooling structures 34 in cross section, also as a cooling fin 36 are formed. The representations in the 8th - 10 are to be understood as any cooling structure 34 in an exhaust duct 18 individually or in combination with other cooling structures shown 34 can be trained. The in the 3 - 10 shown cooling structures 34 can also be combined with each other, both within a common length l of an exhaust passage 18 as well as viewed in the flow direction separated from each other lengths l of an exhaust passage 18 , ie arranged one behind the other in the flow direction.

At the in 8th shown embodiment of cooling structures 34 are the cooling structures 34 also as cooling fins 36 educated. The total of four shown cooling fins 36 each extend from the outer wall 40 the exhaust duct 18 towards the middle and taper off the outside wall 40 towards the middle. Between the respective cooling fins 36 and the adjoining outer wall 40 the exhaust duct 18 are each coolant channels 38 educated.

9 shows further embodiments of as cooling fins 36 designed cooling structures 34 , This illustration is intended to clarify that the cooling structures 34 in the cross section of the exhaust passage 18 considers a variety of protrusions 42 may be to the effective surface of a cooling structure 34 to enlarge. Furthermore, in 9 well recognizable that the number and geometry of the coolant channels 38 for cooling a cooling structure 34 can vary. Particularly suitable Coolant channels 38 with a circular, round or semicircular structure, as in 9 recognizable. In 9 is also on the left side of the exhaust duct 18 shown that the coolant channel 38 not necessarily directly to a cooling structure 34 must border. At the left cooling structure 34 is between the cooling structure 34 and the coolant channel 38 a material bridge 44 in the cylinder head 20 formed, which the cooling structure 34 from the coolant channel 38 separated. The heating of the left cooling structure 34 However, leads to an indirect heating of the web 44 , which eventually heat in the coolant channel 38 transferred and dissipated by this on the cooling fluid. Thus stands the cooling structure 34 in operative connection to the left coolant channel 38 ,

10 shows a further embodiment of an exhaust passage 18 with two different, the geometry of the exhaust duct 18 in the field of cooling structures 34 changed geometry. The left cooling structure 34 is as a cooling fin 36 with a variety of protrusions 42 to increase the effective surface area within the exhaust duct 18 educated. The right cooling structure 34 is also as a cooling fin 36 , but without corresponding projections 42 educated. Between the respective cooling structure 34 and the outer wall 40 the exhaust duct 18 is located in the respective enclosed area a coolant channel 38 , An inlet and a drain are in 10 however, they are preferably as in connection with the embodiment from 7 educated. It can also be several inlets and multiple operations to a coolant channel 38 be provided.

As can be seen from the embodiments shown, coolant channels can 38 within the cross section of an exhaust duct 18 be arranged or outside of an exhaust duct 18 , The cooling structure 34 and the exhaust duct 18 may also be in direct contact or in indirect contact with another element. The decisive factor is that an operative connection between the coolant channel 38 and a cooling structure 34 consists.

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and in consideration of the knowledge of the person skilled in the art. In this regard, it is particularly pointed out again that a cooling structure 34 both in one piece in another element, in particular in a cylinder head 20 or in between a cylinder head 20 and an exhaust gas turbocharger 26 arranged intermediate element 22 may be formed or (completely or partially) as a separate element which is mounted within the respective element or otherwise fixed in its position.

LIST OF REFERENCE NUMBERS

10

Internal combustion engine

12

cylinder

14

exhaust duct

16

opening point

18

Converging exhaust channel

18a

Upper subchannel

18b

lower sub-channel

20

cylinder head

22

intermediate element

24

turbine

26

turbocharger

28

compressor

30

bypass

32

aftertreatment system

34

cooling structure

36

cooling fin

38

Coolant channel

40

outer wall

42

head Start

44

material web

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010023054 A1 [0004]
• WO 2009/019153 A2 [0005]

Claims (10)

Exhaust duct of an internal combustion engine ( 10 ) with at least one coolant channel ( 38 ) for reducing the temperature of the exhaust duct ( 18 ) flowing through the exhaust gas of the internal combustion engine ( 10 ), characterized in that at least in a partial region of the exhaust gas duct ( 18 ) at least one of the cross section of the exhaust passage ( 18 ) changing cooling structure ( 34 ) is formed, which in operative connection to the at least one coolant channel ( 38 ) stands. Exhaust duct according to the preceding claim, characterized in that as a cooling structure ( 34 ) at least one cooling fin ( 36 ) is formed, which in the cross section of the exhaust passage ( 18 ) protrudes. Exhaust duct according to one or more of the preceding claims, characterized in that a plurality of cooling structures ( 34 ) in a longitudinal section 1 of the exhaust gas duct ( 18 ) and formed from the outside in the cross section of the exhaust passage ( 18 ) are arranged protruding. Exhaust duct according to one or more of the preceding claims, characterized in that by at least one as a cooling fin ( 36 ) formed cooling structure ( 34 ) the exhaust duct ( 18 ) at least in a portion of its length in at least two sub-channels ( 18a . 18b ) is divided. Exhaust duct according to one or more of the preceding claims, characterized in that the at least one coolant duct ( 38 ) at least partially within the cooling structure ( 34 ) is trained Exhaust duct according to one or more of the preceding claims, characterized in that at least one cooling structure ( 34 ) in the cross section of the exhaust duct ( 18 ) considers a plurality of projections ( 42 ) are formed. Exhaust duct according to one or more of the preceding claims, characterized in that the cross-section of the exhaust duct ( 18 ) immediately upstream of the at least one cooling structure ( 34 ), in the region of the at least one cooling structure ( 34 ) and immediately downstream of the at least one cooling structure ( 34 ) a maximum deviation of 30 percent relative to the smallest flow cross-section in the area of the cooling structure ( 34 ) having. Internal combustion engine with an exhaust duct ( 18 ) according to one of claims 1 to 6, characterized in that the exhaust duct ( 18 ) at least partially as an integrated exhaust duct ( 18 ) and the at least one cooling structure ( 34 ) in the cylinder head ( 20 ) of the internal combustion engine ( 10 ) is trained. Internal combustion engine with an exhaust duct ( 18 ) according to one of claims 1 to 6 or according to the preceding claim, characterized in that downstream of the at least one cooling rib ( 36 ) an exhaust gas turbocharger ( 26 ) is arranged. Internal combustion engine according to the preceding claim, characterized in that between the cylinder head ( 20 ) of the internal combustion engine ( 10 ) and the exhaust gas turbocharger ( 26 ) an intermediate element ( 22 ) is formed with a cooling device.

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