AT521516B1 - Internal combustion engine, in particular for marine applications - Google Patents

Abstract

The invention relates to an internal combustion engine (100; 200), in particular for marine applications, with at least one exhaust pipe (160, 162; 260) covered at least in sections by a heat protection element (170; 270). In order to ensure that a defined component surface temperature is maintained in a simple manner, it is provided that the heat protection element (170; 270) is liquid-cooled.

Description

Description: The invention relates to an internal combustion engine, in particular for marine applications, with at least one exhaust pipe covered at least in sections by a heat protection element, the heat protection element being liquid-cooled and at least one double-walled housing wall with an inner wall facing the exhaust pipe and an outer wall facing away from the exhaust pipe has, a cooling space for receiving a cooling liquid being formed between the inner wall and the outer wall.

In particular, in marine applications - ie in internal combustion engines, especially in large engines, for ships such as cargo or container ships or other water vehicles - the requirements for the component temperature are very strict to keep the risk of fire low. For components where there is a risk of contact - for example during service work on the internal combustion engine - the component temperature may not exceed 80 ° C. Inaccessible components that cannot be easily touched may have a component temperature of maximum 220 ° C. For internal combustion engines for marine applications, a maximum component surface temperature of 80 ° C to a maximum of 220 ° C must be guaranteed, depending on the position in the internal combustion engine. This is typically achieved with heat shields or a water-cooled exhaust pipe system. However, water-cooled exhaust pipe plants have a number of disadvantages: They are expensive to manufacture because they are usually complex constructions. The complex construction can lead to distortion and leakage problems due to thermal stress, which adversely affects reliability and durability. Multi-walled castings of exhaust manifolds are also relatively cost-intensive and have high strength requirements with regard to thermal stresses, which occur due to the high temperature differences between the water side - around 90 ° C - and the exhaust side - up to 600 ° C. Due to the multi-walled construction, water-cooled exhaust pipe works are relatively heavy.

Since the exhaust heat is given off directly to the coolant in liquid-cooled exhaust manifolds, the thermal efficiency is comparatively poor.

Encapsulated exhaust manifolds are also known in which the exhaust manifold is surrounded by a thermal insulation housing. It is disadvantageous that service work on encapsulated exhaust manifolds involves higher disassembly and assembly costs.

WO 2014/173492 A1 describes a multi-cylinder internal combustion engine with V-shaped rows of cylinders with exhaust gas recirculation, with a cover for covering the V-space between two rows of cylinders, the cover having at least one exhaust gas recirculation cooler.

From WO 07/031637 A1 a heat exchanger module is known, which is arranged in the V space between two rows of cylinders of a V internal combustion engine.

DE 295 18 189 U1 describes an exhaust manifold system with an exhaust pipe that can be connected to one or more exhaust ducts, the exhaust pipe being designed as a one-part or multi-part inner tube group and surrounded by a capsule and between the capsule and the inner tube group Air gap is located. The capsule is made up of two shell walls, which form a cavity in which a cooling water of the cooling circuit of the engine flows.

DE 197 35 388 A1 relates to a shielding element for motor vehicles with a first shell, a second shell and a flow path arranged between the first and second shell for a fluid medium.

DE 29 07 767 A1 shows a protective device for exhaust pipes of internal combustion engines with a double-walled protective screen which has a coolant space through which a coolant can flow between its two closely connected, spaced-apart walls.

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AT 521 516 B1 2020-02-15 Austrian Patent Office [0010] WO 2017/137654 A1 discloses an internal combustion engine which has a heat protection shield for an exhaust pipe, which surrounds the exhaust pipe in a collar-like manner. The coolant-cooled heat shield also serves as a holder for an insulating plate that covers a cavity that receives the exhaust pipes.

From GB 1 554 540 A exhaust pipes are known, which are surrounded by a double-walled liquid-cooled housing.

[0012] US 2015/0247442 A1 discloses an exhaust manifold for an internal combustion engine, wherein exhaust pipes of the exhaust manifold are surrounded by an air shielding zone. Furthermore, the exhaust gas collector has a cooling jacket which surrounds the air shielding zone. A similar exhaust manifold is disclosed in CN 105 986 873 A.

WO 2010/039590 A2 also relates to an exhaust gas system which is surrounded by a cooling jacket through which cooling liquid flows.

[0014] Furthermore, WO 2007/139522 A also shows an exhaust gas collector which is arranged in a liquid-cooled and insulated housing.

[0015] DE 43 42 572 C1 describes an exhaust system for a supercharged internal combustion engine, exhaust-gas-carrying components being arranged in an exhaust-gas-tight housing. Due to openings in the exhaust gas-carrying components, the space between the exhaust gas-carrying components and the housing is filled with exhaust gas, which can be blown off via a bypass line of the exhaust gas turbine.

[0016] DE 27 44 964 A1 shows an exhaust pipe system for a multi-cylinder reciprocating piston machine, the exhaust pipe being surrounded by a water-cooled insulating wall.

The object of the invention is to ensure in a simple manner compliance with a defined component surface temperature in an internal combustion engine of the type mentioned.

According to the invention, this object is achieved in that the heat protection element is designed as a coolant supply or coolant discharge of a cylinder head of the internal combustion engine.

In comparison to simple, in particular uncooled heat shields, the surface temperature can be better controlled and thus the contact temperature on the outside of the internal combustion engine can be ensured in a simple manner. As a result, the cooling conditions can be improved, in particular for internal combustion engines that are used, for example, in the marine environment, in rail vehicles or commercial vehicles.

[0020] The heat protection element fulfills several functions:

(1) prevention of heat radiation;

(2) shielding against fuel and oil splashes that may hit the hot exhaust pipe system from the surroundings and cause a fire hazard, and (3) protection against contact.

An advantageous embodiment of the invention provides that an inlet channel and an outlet channel for the cooling liquid open into the cooling space.

It when the heat protection element is formed separately from the exhaust pipe, wherein a defined minimum distance is preferably formed between the heat protection element and the exhaust pipe is particularly advantageous. The fact that the heat protection element is designed separately from the exhaust gas line means that complex design changes to the exhaust gas line are not necessary.

In particular, the reliability and durability of the exhaust pipe is not adversely affected. Because those occurring in the exhaust pipe and the heat protection element

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Temperature gradients are much lower than with known water-cooled exhaust pipe plants, distortion and systematic leakage problems can be avoided. The reliability and durability of the internal combustion engine is thus not adversely affected.

Due to the minimum distance to the exhaust pipe there is no contact to the hot surfaces of the exhaust pipe. The liquid-cooled heat protection element therefore does not act as a heat exchanger here; rather, the heat protection element forms a housing through which liquid flows, which covers the area of the exhaust gas lines as completely as possible, the interior wall of the heat protection element being exposed only to radiant heat.

A structurally simple embodiment of the invention provides that the inner wall and the outer wall are at least partially parallel to each other, preferably the inner wall and / or the outer wall are at least partially flat. This enables simple shaping and production. The inner wall can be formed by a first plate and the outer wall by a second plate, the two plates being firmly connected to one another via lateral webs. The two plates and the webs can be formed by separate components and welded or screwed together, or else can be made in one piece - for example in one casting process. In particular, the entire heat protection element can be plate-shaped.

The heat protection element can be made of sheet steel, cast iron, aluminum or plastic.

In a further embodiment of the invention it is provided that the heat protection element is designed as a multi-functional component. For example, the heat protection element can be designed as a component carrier and have at least one receptacle for at least one component, preferably an electronic control unit and / or an ignition coil. Furthermore, the heat protection element can be designed to be sound-insulating. It is also possible for at least one air-guiding duct and / or one cable duct to be integrated in the heat protection element. Furthermore, the heat protection element can be designed as an oil mist separator. Furthermore, the heat protection element can have at least one sound-reducing measure, the sound-reducing measure preferably being formed by a sound-absorbing layer or a sound-reducing shape of the housing wall, in particular by a honeycomb-like surface structure.

[0028] For example, the heat protection element can be designed as a coolant supply line or coolant discharge line of the cylinder head. In this case, the heat protection element can have, for example, pipe sections with O-ring seals which, when fitted, project into corresponding openings in the cylinder heads.

Thus, in addition to thermal shielding, the heat protection element can also function as a coolant collector, an acoustic cover, a support for further components - such as an electronic control unit and / or an ignition coil -, an air and / or coolant guide, a cable guide and / or take over the oil mist separation. This additionally increases the use effect of the heat protection element.

In one embodiment variant of the invention it is provided that the heat protection element is formed by a cover which surrounds the exhaust pipe on at least two, preferably on at least three sides, the cover preferably being at least at an angle related to the central axis of the exhaust pipe Extends 250 °. Conveniently, the heat protection element has at least two, preferably at least three - at an angle, preferably between 30 ° and 150 °, inclined to one another, arranged double-walled housing walls, each with an inner wall facing the exhaust pipe and an outer wall facing away from the exhaust pipe, each between the inner wall and Outside wall, a cooling space for receiving a cooling liquid is formed. A cover is to be understood here as a concave housing part which forms a cavity in which at least one exhaust gas line is positioned. Trained as covers

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Heat protection elements are particularly suitable for internal combustion engines with cylinders arranged in series, the exhaust pipe running along a long side of the engine housing. Particularly good cooling can be achieved if at least two cooling rooms communicate with one another from adjacent housing walls.

In a further embodiment of the invention it is provided that the heat protection element covers a V-space formed in the area between two rows of cylinders of a V-internal combustion engine, at least one, preferably two exhaust gas lines being arranged in the V-space. Conveniently, the heat protection element is fixedly connected to the motor housing of the V-type internal combustion engine via at least one support element, the support element preferably having at least one coolant channel communicating with the cooling chamber of the heat protection element. The heat protection element can be designed, for example, as an essentially flat cover plate or can have a section designed essentially as a flat cover plate.

In an embodiment variant of the invention it is provided that at least one side housing wall of the heat protection element is arranged between two adjacent cylinder head covers. This also covers the area between two adjacent cylinder head covers. The lateral housing walls can be adapted to the contour of the cylinder hoods and can be mechanically connected to the cylinder head. The mechanical connection to the cylinder head enables additional lateral support of the heat protection element.

Another embodiment of the invention provides that at least one support element is arranged between at least two adjacent cylinder head covers, which firmly connects the heat protection element to a cylinder head or engine housing of the internal combustion engine. Here too, the support element enables mechanical support of the heat protection element. It is particularly advantageous if at least one support element has a thermal or acoustic insulating element. The supporting element thus acts both for support and for thermal or acoustic insulation of the internal combustion engine.

[0034] The heat protection element can advantageously be connected to a coolant circuit of the internal combustion engine. In marine applications, the cover can also be used with sea or Through which seawater flows.

With the present invention, it is possible to ensure a defined component surface temperature, but to avoid complicated multi-walled castings of exhaust manifolds and at the same time to ensure good accessibility for service work on exhaust manifolds and cylinder heads.

The invention is explained in more detail below with reference to the non-restrictive exemplary embodiments shown in the figures. In it show:

1 shows an internal combustion engine according to the invention in a first embodiment variant in a front view, [0038] FIG. 2 shows an internal combustion engine according to the invention in a second embodiment variant in a section along the line II-II in FIG. 3, [0039] FIG. 3 this internal combustion engine in a plan view, [0040] FIG. 4 an internal combustion engine according to the invention in a third embodiment variant in a section analogous to FIG. 2 and [0041] FIG. 5 an internal combustion engine according to the invention in a fourth embodiment variant in a front view.

Functionally identical parts are provided with the same reference numerals in the embodiment variants shown in FIGS. 1 to 4.

1 shows a V internal combustion engine 100 with an engine housing 110, a first 120 and a second row of cylinders 122 with first 130 and second cylinder heads 132, the two rows of cylinders 120, 122 being arranged in a V shape and a V- Room 102 between

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The V-space 102 is covered on the outside by a liquid-cooled heat protection element 170, which is designed as a flat cover plate 172. The heat protection element 170 has a double-walled housing wall 180 with an inner wall 180i facing the exhaust pipe 160, 162 and an outer wall 180a facing away from the exhaust pipes 160, 162. The heat protection element 170 is connected via a support element 190 to the engine housing 110 of the internal combustion engine 100, which extends in the region of the engine longitudinal plane 101 between the first exhaust line 160 and the second exhaust line 162.

A cooling space 185 for receiving a cooling liquid is formed between the inner wall 180i and the outer wall 180a of the double-walled housing wall 180. The cooling space 185 is connected to cooling liquid channels 185a, 185b — an inflow channel and an outflow channel for the cooling liquid — which are arranged within the support element 190 in the exemplary embodiment shown.

The inner wall 180i and the outer wall 180a of the heat protection element 170 are formed parallel to one another and flat and arranged at a distance a from one another.

The heat protection element 170 forms together with the engine housing 110, the first cylinder head 130, the first valve cover 140, the second cylinder head 132 and the second valve cover 142 from a cavity 175 connected to the ambient air, in which the first exhaust pipe 160 and the second Exhaust line 162 are arranged.

The second embodiment variant shown in FIG. 2 differs from the first exemplary embodiment shown in FIG. 1 in that the heat protection element 170 has a plurality of double-walled housing walls 180, 181, 182, 183, 184. The adjacent housing walls 180, 181 and the adjacent housing walls 180, 182 are each inclined at an angle γτ of approximately 90 ° to one another. The adjacent housing walls 181, 183 and the adjacent housing walls 182, 184 are each inclined to one another at an angle γ ₂ of approximately 135 °.

Each housing wall 180, 181, 182, 183, 184 has an inner wall 180i, 181 i, 182i, 183i, 284i facing the exhaust pipes 160, 162 and an outer wall 180a, 181a, 182a facing away from the exhaust pipes; 183a, 184a. Each between an inner wall 180i, 181 i, 182i; 183i, 184i and a corresponding outer wall 180a, 181a, 182a, 183a, 184a, a cooling space 185, 186, 187, 188, 189 is arranged for receiving a cooling liquid. The cold rooms 185, 186, 187, 188, 189 are connected to one another in a hydraulically communicating manner.

The housing walls 181, 183 and the housing walls 182, 184 each extend into the areas between the adjacent cylinder head covers 140 and 142 of the cylinder banks 120, 122. A separate cylinder head cover 140, 142 is provided here for each cylinder.

FIG. 3 shows the internal combustion engine 100 shown in FIG. 2 in a top view, it being clearly evident how the double-walled housing walls 181, 183 of the heat protection element 170 extend between the cylinder head covers 140, 142.

In the third embodiment shown in FIG. 4, support elements 191, 192 are provided between each two adjacent cylinder head covers 140, 142 of the cylinder heads 130, 132, with which the heat protection element 170 is connected to the respective cylinder heads 130, 132. The support elements 191, 192 serve on the one hand to support the heat protection element 170 and on the other hand as a carrier for at least one heat or sound-absorbing element

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Insulating element 195, 196. The insulating elements 195, 196 can be fastened to the support elements 191, 192 or can also be embodied integrally therewith.

5 shows a further exemplary embodiment of an internal combustion engine 200 with an engine housing 210 with a row of cylinders 220 with cylinders arranged in series, a cylinder head 230 and a valve cover 240 adjoining this. The cylinder head 230 is provided with an inlet line 250 and an exhaust line 260 connected. Exhaust line 260 extends approximately in the longitudinal direction of internal combustion engine 200, that is to say approximately parallel to a crankshaft axis (not shown further).

The exhaust pipe 260 is covered from the environment by a - as an angled cover 272 - liquid-cooled heat protection element 270, which is attached to the side of the internal combustion engine 200. In the exemplary embodiment, the cover 272 surrounds the exhaust pipe 260 on three sides 264, 266, 268 and extends over an angle β of at least 250 ° measured around the central axis 260a of the exhaust pipe 260.

The heat protection element 270 has a first housing wall 280, a second housing wall 281 and a third housing wall 282, each housing wall 280, 281, 282 being double-walled and flat and each having an inner wall 280i, 281 i, 282i facing the exhaust gas line 260 and has an outer wall 280a, 281a, 282ia facing away from the exhaust pipe 260. Inner wall 280i, 281 i, 282i and outer wall 280a, 281a, 282a of each housing wall 280, 281, 282 are flat and parallel and each span a cooling space 285, 286, 287 for receiving a cooling liquid. The spacing between inner wall 280i, 281i, 282i and outer wall 280a, 281a, 282a of each housing wall 280, 281, 282 is designated by reference symbol a. The distances a between the housing walls 280, 281, 282 can be of the same or different dimensions.

Adjacent housing walls 280, 281, 282 are each inclined at an angle γ to one another. The cooling rooms 285, 286, 287 of the three housing walls 280, 281, 282 are hydraulically connected to one another.

The heat protection element 270 forms together with the cylinder head 230 a cavity 275 connected to the ambient air, in which the exhaust pipe 260 is arranged.

In all design variants, the heat protection element 170, 270 is from the exhaust pipe 160, 162; 260 formed separately. Between the heat protection element 170, 270 and the exhaust pipe 160, 162; 260, a defined minimum distance b is provided in each case. The fact that the exhaust pipes 160, 162; 260 from the heat protection elements 170, 270, distortion caused by large temperature gradients can be avoided.

The between the inner wall 180i; 181 i, 182i, 183i, 184i; 280i, 281 i, 282i and the outer wall 180a; 181a, 182a, 183a, 184a; 280a, 281a, 282a arranged cold room 185, 186, 187, 188, 189; 285, 286, 287 can simultaneously be designed as a coolant collection channel.

The heat protection element 170, 270 can each be designed as a multifunction element and, in addition to thermal protection, can also take on other functions, such as, for example, sound insulation, coolant guidance, air or equipment management, cable routing, oil mist separation or the like.

Claims (20)

claims 1. Internal combustion engine (100; 200), in particular for marine applications, with at least one exhaust pipe (160, 162; 260) covered at least in sections by a heat protection element (170; 270), the heat protection element (170; 270) being liquid-cooled and at least one double-walled housing wall (180, 181, 182, 183, 184; 280, 281, 282) with an inner wall (180i, 181i, 182i, 183i, 184i; 280i, 281i, 282i) facing the exhaust pipe (160, 162; 260) ) and one of the exhaust pipes (160, 162; 260) facing away from the outer wall (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a), with between the inner wall (180i, 181 i, 182i, 183i, 184i; 280i, 281 i, 282i) and outer wall (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a) a cooling space (185, 186, 187, 188, 189; 285, 286, 287) is designed to hold a cooling liquid, characterized in that the heat protection element (170; 270) as a coolant supply or coolant discharge of a cylinder head of the internal combustion engine ft machine is formed. 2. Internal combustion engine (100; 200) according to claim 1, characterized in that in the cooling space (185, 186, 187, 188, 189; 285, 286, 287) at least one coolant channel (185a, 185b) for the coolant opens. 3. Internal combustion engine (100; 200) according to claim 1 or 2, characterized in that the inner wall (180i, 181i, 182i, 183i, 184i; 280i, 281 i, 282i) and the outer wall (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a) are at least partially parallel to one another. 4. Internal combustion engine (100; 200) according to one of claims 1 to 3, characterized in that the inner wall (180i, 181i, 182i, 183i, 184i; 280i, 281 i, 282i) and / or the outer wall (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a) are at least partially flat. 5. Internal combustion engine (100; 200) according to one of claims 1 to 4, characterized in that the cooling space (185, 186, 187, 188, 189; 285, 286, 287) is designed as a coolant collection channel. 6. Internal combustion engine (100; 200) according to one of claims 1 to 5, characterized in that the heat protection element (170; 270) from the exhaust pipe (160, 162; 260) is formed separately, preferably between the heat protection element (170; 270 ) and the exhaust pipe (160, 162; 260) a defined minimum distance (b) is formed. 7. Internal combustion engine (100; 200) according to one of claims 1 to 6, characterized in that between the heat protection element (170; 270) and the exhaust pipe (160, 162; 260) a - preferably air-guiding or air-filled - cavity (175; 275 ) is trained. 8. Internal combustion engine (100; 200) according to one of claims 1 to 7, characterized in that the heat protection element (170; 270) is designed as a multi-functional component. 9. Internal combustion engine (100; 200) according to claim 8, characterized in that the heat protection element (170; 270) is designed as a component carrier and has at least one receptacle for at least one component, preferably an electronic control unit and / or an ignition coil. 10. Internal combustion engine (100; 200) according to claim 8 or 9, characterized in that the heat protection element (170; 270) has at least one sound-reducing measure, the sound-reducing measure preferably being formed by a sound-absorbing layer or a sound-reducing shape, in particular a honeycomb-like surface structure is. 11. Internal combustion engine (100; 200) according to one of claims 8 to 10, characterized in that the heat protection element (170; 270) forms at least one air-guiding channel or at least one air-guiding channel is integrated in the heat protection element (170; 270). 7.13 AT 521 516 B1 2020-02-15 Austrian patent office 12. Internal combustion engine (100; 200) according to one of claims 8 to 11, characterized in that in the heat protection element (170; 270) at least one cable duct is integrated. 13. Internal combustion engine (100; 200) according to one of claims 8 to 12, characterized in that the heat protection element (170; 270) is designed as an oil mist separator or is integrally formed with an oil mist separator. 14. Internal combustion engine (200) according to any one of claims 1 to 13, characterized in that the heat protection element (270) is formed by a cover (272) which the exhaust pipe (260) on at least two, preferably at least three sides (262, 266, 268), the cover hood (272) preferably extending over an angle (β) of at least 250 ° related to the central axis (260a) of the exhaust gas pipe (260). 15. Internal combustion engine (100, 200) according to one of claims 1 to 14, characterized in that the heat protection element (170, 270) at least two, preferably at least three - at an angle (γ ^ γ ₂ ; γ), preferably between 30 ° and 150 °, inclined adjacent to each other, double-walled housing walls (180, 181, 182, 183, 184; 280, 281, 282), each with an inner wall (180i, 181i, 182i, 183i, facing the exhaust pipe (160, 162; 260), 184i; 280i, 281i, 282i) and an outer wall facing away from the exhaust gas pipe (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a), each between the inner wall (180i, 181 i, 182i, 183i, 184i; 280i , 281 i, 282i) and outer wall (180a, 181a, 182a, 183a, 184a; 280a, 281a, 282a), a cooling space (185, 186, 187, 188, 189; 285, 286, 287) is designed to hold a cooling liquid , preferably at least two cold rooms (185, 186, 187, 188, 189; 285, 286, 287) of adjacent housing walls (180, 181, 182; 280, 281, 282) communicate. 16. Internal combustion engine (100) according to one of claims 1 to 15, with at least two V-shaped rows of cylinders (120, 122), characterized in that the heat protection element (170) is formed in the area between the two rows of cylinders (120, 122) V- Covering space (102), at least one, preferably two exhaust gas lines (160, 162) being arranged in the V space (102). 17. Internal combustion engine (100) according to claim 16, characterized in that the heat protection element (170) via at least one support element (190) with the motor housing (110) of the internal combustion engine (100) is firmly connected, preferably the support element (190) at least one has coolant channel (185a, 185b) communicating with the cooling space (185) of the heat protection element (170). 18. Internal combustion engine (100) according to claim 16 or 17, characterized in that the heat protection element (170) is designed as a substantially flat cover plate (172) or has a section formed as a substantially flat cover plate (172). 19. Internal combustion engine (100) according to one of claims 1 to 18, characterized in that at least one housing wall (181, 182, 183, 184) of the heat protection element (170) is arranged between two adjacent cylinder head covers (140, 142) of the internal combustion engine (100) is. 20. Internal combustion engine (100) according to one of claims 1 to 19, characterized in that between at least two adjacent cylinder head covers (140, 142) at least one support element (191, 192) is arranged, which the heat protection element (170) with a cylinder head (130 , 132) or motor housing (110) of the internal combustion engine (100), preferably at least one support element (191, 192) having an insulating element (195, 196).