FI130147B

FI130147B - Internal combustion engine

Info

Publication number: FI130147B
Application number: FI20175732A
Authority: FI
Inventors: Ulrich Deisenhofer; Matthias Söngen
Original assignee: Man Diesel & Turbo Se
Priority date: 2016-09-08
Filing date: 2017-08-16
Publication date: 2023-03-14
Also published as: FI20175732A; JP6969928B2; FI20175732A7; KR20180028381A; KR102394997B1; JP2018040350A; CN107806351B; DE102016116802A1; CN107806351A

Abstract

An internal combustion engine (20) with a cylinder head (21); with at least one cylinder; wherein in the cylinder head (21) for each cylinder at least one gas exchange valve for charge air on the inlet side each and at least one gas exchange valve (22) for exhaust gas on the exhaust side each is received; wherein each gas exchange valve comprises a valve stem (23) mounted in a valve guide (24), which valve stem (23) carries a valve body (25), and a valve seat ring (26) interacting with the valve body (25); wherein the cylinder head (21) for each cylinder comprises an inlet port (37) for charge air interacting with the respective gas exchange valve on the inlet side and an exhaust port (30) for exhaust gas interacting with the respective gas exchange valve (22) on the exhaust side; and wherein the exhaust port (30) interacting with the respective gas exchange valve (22) on the exhaust side is air-flushed.

Description

Internal combustion engine

The invention relates to an internal combustion engine.

Fig. 1 shows an extract from an internal combustion engine 1 in the region of a cylinder head 2 and a gas exchange valve 3 on the exhaust side received by the cylinder head 2. Furthermore, laterally, next to the gas exchange valve 3 on the exhaust side, a gas exchange valve 4 on the inlet side is shown, in sections. By way of the gas exchange valve 4 on the inlet side charge air can be fed to a combustion chamber of the respective cylinder. By way of the respective gas exchange valve 3 on the exhaust side, exhaust gas can be discharged from the combustion chamber of the respective cylinder. Fuel to be combusted in the cylinder is fed to the same preferentially via an injector which is not shown. Of the gas exchange valve 3 on the exhaust side a valve stem 5, a valve body 6, a valve guide 7 and a valve seat ring 8 are shown. The valve stem 5 of the gas exchange valve 3 on the exhaust guide is moveably guided up and down in the valve guide 7 so that the valve stem 5 together with the valve body 6 carried by the valves stem 5 can perform a stroke movement. In the closed state of the gas exchange valve 3 on the exhaust side, a section 9 of the valve body 6 lies against a valve seat 10 provided by the valve seat ring 8. In the opened state of the gas exchange valve 3, the section 9 of the valve body 6 is lifted off the valve seat 10 of the valve seat ring

Q 8. The cylinder head 2 provides an inlet port 11 for charge air interacting with the

N respective gas exchange valve 4 on the inlet side and an exhaust gas port 12 for

S 25 exhaust gas interacting with the gas exchange valve 3 on the exhaust side for

S each cylinder. In particular when the respective gas exchange valve 4 on the inlet z side is opened, charge air, originating from the inlet port 11, can flow into the

N combustion chamber of the respective cylinder. In particular when the respective 5 gas exchange valve 3 on the exhaust side is opened, exhaust gas can flow out of > 30 the combustion chamber of the respective cylinder into the respective exhaust port 12.

Fig. 1, furthermore, shows a spring element 13 interacting with the gas exchange valve 3 on the exhaust side. The spring element 13 is part of the valve timing gear for the respective gas exchange valve.

In the case of internal combustion engines with increasing performance density and more stringent Miller combustion methods, the fuel quantities to be fed in and the compression ratios become ever greater. Above all, in the case of direct- injection internal combustion diesel engines, this results in so-called injection — spray patterns get closer to components on the combustion chamber side such as the gas exchange valves, as a result of which the same are exposed to higher temperatures. This applies in particular to the gas exchange valves on the exhaust side. There is therefore an increased need for better cooling the gas exchange valves of an internal combustion engine, in particular the gas exchange valves on — the exhaust side.

Starting out from this, the present invention is based on the object of creating a new type of internal combustion engine with which better cooling in particular of the gas exchange valves on the exhaust side is possible.

This object is solved through an internal combustion engine according to claim 1. n According to the invention, an exhaust port interacting with the respective gas

S exchange valve on the exhaust side is air-flushed. With the invention it is proposed

N that the respective exhaust port for the exhaust gas interacting with a respective 2 25 gas exchange valve on the exhaust side is air-flushed. By blowing air, which is

I relatively cold compared with the exhaust gas, into the exhaust port with in a particular closed gas exchange valve on the exhaust side, the hot exhaust gases = can be pushed out of the exhaust port into an exhaust line and accordingly kept = away from the gas exchange valve on the exhaust side. An effective cooling in

N 30 particular of the gas exchange valves on the exhaust side is thereby possible.

The exhaust port interacting with the respective gas exchange valve on the exhaust side is flushed either with charge air, which can be branched off a charge air supply of the internal combustion engine or with compressed air, which can be made available by being branched off a separate compressed-air supply of the internal combustion engine. The air-flushing of the respective exhaust port with charge air has the advantage that no separate compressed-air supply is required.

Air-flushing of the respective exhaust port via compressed air that is made available by a separate compressed-air supply has the advantage that by way of the compressed-air supply a pressure for air-flushing that is greater than an exhaust gas pressure can always be provided.

According to a first advantageous further development of the invention, an air guide bore extending in axial direction of the valve stem, at least one air guide bore extending in or approximately in radial direction of the same and a groove on an outer surface is introduced into the respective valve stem, wherein the respective air guide bore extending in or approximately in radial direction communicates with the air guide bore extending in axial direction and the groove.

In the respective valve guide, at least one air guide bore extending in or approximately in radial direction of the same is introduced, which can be supplied — with air from a charge air supply or compressed-air supply and, independently of the stroke position of the valve stem, communicates with the groove of the valve stem. The air guide bore of the valve stem extending in axial direction of the valve stem opens into the respective exhaust port via air guide bores of the valve body

S in the region of the valve body so that on the one hand the respective exhaust port

N 25 is air-flushed and on the other hand the respective valve body is or gets air-cooled.

S Accordingly, with this first advantageous further development of the invention, it is 8 not only the respective exhaust port that can be flushed with air but the respective

E valve body is also air-cooled.

O o

S 30 According to a second advantageous further development of the invention, at least = one air guide bore is introduced into the at least one valve guide, which can be supplied with air from a charge air supply or compressed-air supply and which communicates with a gap between the respective valve guide and the respective valve stem, wherein via the gap between the respective valve guide and the respective valve stem the respective exhaust port is air-flushed. This advantageous further development of the invention is simple in terms of construction.

According to a third advantageous further development of the invention, at least one air guide groove is introduced into the respective valve seat ring, which can be supplied with air from a charge air supply or compressed air supply and which, via a gap between the respective guide seat ring and the cylinder head or via a bore in the valve seat ring, communicates with the respective exhaust port, wherein the gap between the respective valve seat ring and the cylinder head or via the bore in the valve seat ring the respective exhaust port is air-flushed. This further development of the invention is also simple in terms of construction and also makes possible an air cooling of the respective valve body.

Preferred further developments of the invention are obtained from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail by way of the drawing without being restricted to this.

Thereit shows:

Fig. 1: a cross section by way of extract through an internal combustion

N engine according to the prior art in the region of a gas exchange a. valve on the exhaust side; > 25 Figs. 2a-2c: details of a first internal combustion engine according to the

I invention; a

N Figs. 3a-3d: details of a second internal combustion engine according to the 5 invention;

S Figs. 4a-4b: details of a third internal combustion engine according to the invention; and

Figs. 5a-5b: details of a fourth internal combustion engine according to the invention.

Figs. 2a to 2c show details of a first internal combustion engine 20 according to 5 the invention, in the region of a cylinder head 21 and of a gas exchange valve 22 on the exhaust side of a cylinder of the internal combustion engine received in the cylinder head 21. Of the gas exchange valve 22 on the exhaust side a valve stem 23, a valve guide 24, a valve body 25 and a valve seat ring 26 are shown. The valve stem 23 is moveably guided up and down in the valve guide 24 so that the valve body 25, controlled via a valve timing gear, can perform a stroke movement.

Of the valve timing gear, a spring element 27 is shown. In particular when the gas exchange valve 22 is closed, a section 28 of the valve body 25 lies against a valve seat 29 of the valve seat ring 26. By contrast, in particular when the gas exchange valve 22 is opened, the section 28 of the valve body 25 is lifted off the valve seat 29 of the valve seat ring 26. In this case, exhaust gas can then flow, via the opened gas exchange valve on the exhaust side, out of a combustion chamber of the cylinder into an exhaust port 30 for the exhaust gas interacting with the gas exchange valve 22 on the exhaust side, wherein the cylinder head 21 provides this exhaust port 30. The exhaust port 30 interacting with the gas exchange valve 22 on the exhaust side is air-flushed according to the invention in order to push exhaust gas out of the exhaust port 30 into an exhaust line thereby keeping the hot exhaust gas away from the gas exchange valve 22. The air-flushing of the exhaust port 30 can take place either by way of charge air or by way of separate

S compressed air, wherein the charge air can be branched off the air supply system

N 25 of the internal combustion engine and wherein the compressed air can be 3 provided by a separate compressed-air supply of the internal combustion engine.

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= a In the exemplary embodiment shown in Figs. 2a to 2c, an air guide bore 31 (see = Fig. 2b) is introduced into the valve stem 23 which extends in axial direction of the 3 30 same. Furthermore, a plurality of air guide bores 32 preferentially extending in radial direction of the valve stem 31 are introduced into the same, wherein these air guide bores 32 extending in radial direction communicate on the one hand with the air guide bore 31 extending in axial direction and on the other hand communicate with a groove 33, which is formed on an outer surface of the valve stem 23 in particular in the form of a turned recess.

Inthe valve guide 24, a plurality of air guide bores 34 preferentially extending in radial direction are likewise introduced. These air guide bores 34 of the valve guide 24 can be supplied with air emanating from the air supply or the compressed-air supply, wherein the air guide bores 34 of the valve guide 24 communicate with the groove 33 of the valve stem 23 independently of the stroke position of the valve stem 23 so that in any position of the valve stem 23 air, emanating from the air guide bores 34 of the valve guide 24, can get into the air guide bore 31 of the valve stem 23 via the air guide bores 32 of the valve stem 23.

The air guide bore 31 of the valve stem 23 extending in axial direction of the valve stem 23 opens into the respective exhaust gas port 30 in the region of the valve seat ring 26 via air guide bores 35 of the valve body 25 (see Fig. 2a) substantially extending in radial direction, wherein via the air, which issues from the valve body 25 via the air guide bores 35 and enters the exhaust port 30, the respective exhaust port 30 can be air-flushed on the one hand and the respective valve body 25 can be air-cooled on the other hand. According to Fig. 2c, the air supply of the air guide bores 34, 32 and 31 is effected via a bore 36 in the cylinder head 21, which communicates with an inlet chamber 37 of the cylinder head 21 for charge air and thus branches off charge air from the inlet chamber 37 conducting it in the direction of the air guide bores 34 for air-flushing. Accordingly, in the exemplary

S embodiment of Figs. 2a to 2c, air is conducted via the valve guide 24 and the

N 25 valve stem 23 in the direction of the valve body 25 of the gas exchange valve 22.

S The valve stem 23 to this end comprises the air guide bore 31 extending in axial 8 direction and preferentially a plurality of air guide bores 32 preferentially extending

E in radial direction. The valve guide 24 preferentially comprises a plurality of guide & bores 34 likewise preferentially extending in radial direction. By way of the groove

R 30 33 in the outer surface of the valve stem 23 it is ensured that regardless of the

S stroke position of the gas exchange valve, cooling air can be supplied to the abovementioned air guide bores and can get into the region of the valve stem 23 and valve body 25.

Details of a second exemplary embodiment of an internal combustion engine 40 according to the invention are shown by Figs. 3a, 3b and 3c, wherein Fig. 3a in turn shows an extract from the internal combustion engine 40 in the region of a cylinder head 41 and a gas exchange valve 42 on the exhaust side received and guided in the cylinder head 41. Of the gas exchange valve 42 on the exhaust side, a valve stem 43, a valve guide 44, a valve body 45 and a valve seat ring 46 are — shown. The valve stem 43 can be moved up and down independently of a movement initiated by a valve timing gear, wherein of the valve timing gear in turn merely a spring element 47 is shown. In particular when the gas exchange valve 42 is closed, a section 48 of the valve body 45 lies against a valve seat 49 of the valve seat ring 46. When by contrast the gas exchange valve 42 is opened, the — section 48 of the valve body 45 is lifted off the valve seat 49 of the valve seat ring 46, so that exhaust gas can then flow out of a combustion chamber of the respective cylinder into an exhaust port 50 for exhaust gas interacting with the gas exchange valve 42 on the exhaust side. In Figs. 3a to 3c, it is provided for the air- flushing of the exhaust port 50 that at least one air guide bore 51 is introduced into the valve guide 44 for the valve stem 43, preferentially a plurality of air guide bores 51 is introduced into the valve guide 44, which both with respect to the axial direction and also with respect to the radial direction are slanted, so that their axes include a defined angle a which is unequal to 180°. According to Fig. 3b, the axes

S of these air guide bores 51 converge in a direction facing the valve body 45. The

N 25 air guide bores 51 of the valve guide 44 can be supplied with air emanating from

S the charge air supply or compressed-air supply, wherein the air guide bores 51 of 8 the valve guide 44 communicate with a gap 52 which is formed in a lower section

E of the valve guide 44 between the valve guide 44 and the valve stem 43. By way & of this gap 52, between the respective valve guide 44 and the respective valve

R 30 stem 43, the respective exhaust port 50 for the exhaust gas can be air-flushed.

S Because of this, exhaust gas can be pushed out of the exhaust port 50 into an exhaust line.

In the exemplary embodiment of Figs. 3a, 3b, 3c and 3d, an inner surface is introduced into the valve guide 44 for forming the annular gap 52, which delimits the gap 52 between the valve guide 44 and the valve stem 43.

From Fig. 3b it is evident, furthermore, that into the valve guide 44 a further groove 44 is introduced on the outside. The air guide bores 51 of the valve guide 44 communicate with the gap 52 and the groove 54. The groove 54 and via the groove 54 the air guide bores 51 can be supplied with air, namely as already explained emanating from the charge air supply or the compressed-air supply. As is evident from the section of Fig. 3c, the air-flushing in the exemplary embodiment of Figs. 3a, 3b, 3c and 3d is effected by way of charge air, namely via charge air that is branched off an inlet port 55 of the respective cylinder and emanating from the inlet port 55 is conducted in the direction of the groove 57 of the valve guide 44 — via an air guide bore 56 of the cylinder head 41 and of an air passage 57.. As already explained, the air, emanating from the groove 54 of the valve guide 44, flows via the air guide bores 51 into the gap 52 and from the gap 52 into the exhaust port 50. While in the exemplary embodiment of Figs. 2a to 2c in addition to the air-flushing of the exhaust port 30 the valve body 25 can also be directly cooled with air, merely an air-flushing of the exhaust port 50 takes place in the exemplary embodiment of Figs. 3a to 3d.

Q Figs. 4a, 4b show details of a further internal combustion engine 60 according to

N the invention, wherein Fig. 4a shows an extract from the internal combustion

S 25 engine 60 in the region of a cylinder head 61, a gas exchange valve 62 on the

S exhaust side and a gas exchange valve 63 on the inlet side. Both gas exchange z valves 62, 63 are guided in the cylinder head 61. An exhaust port 64 for exhaust

N gas interacts with the gas exchange valve 62 on the exhaust side. An inlet port 65 5 for charge air interacts with the gas exchange valve 63 on the inlet side. In > 30 particular when the gas exchange valve 63 on the inlet side is opened, charge air, emanating from the inlet port 65, can get into a combustion chamber of the respective cylinder. In particular when the gas exchange valve 62 on the exhaust side is opened, exhaust gas can flow out of the combustion chamber of the respective cylinder into the exhaust port 64.

Fig. 4a shows a valve stem 66 of the gas exchange valve 62 on the exhaust side, which carries a valve body 67 and is guided in a valve guide 68. Furthermore,

Fig. 4a shows a valve stem 69 of the gas exchange valve 63 on the inlet side, which carries a valve body 70 and is guided in a valve guide 71. Of the gas exchange valve 63 on the inlet side, a valve seat ring 72 is shown, furthermore, while Fig. 4a likewise shows a valve seat ring 73 of the gas exchange valve 62 on the exhaust side.

For air-flushing the exhaust port 64 interacting with the gas exchange valve 62 on the exhaust side, it is provided in the exemplary embodiment of Figs. 4a, 4b that in the valve seat ring 73 at least one air guide groove 74 is introduced. According to

Fig. 4b, two air guide grooves 74 which are arranged on top of one another are introduced into the valve seat ring 73, which communicate with one another via an aperture 75.

The upper air guide groove 74 of the valve seat ring 73 shown in Fig. 4b can be supplied with air for air-flushing the exhaust port 64, namely charge air or compressed air from the charge air supply or compressed-air supply, wherein this air supplied to the upper air guide groove 74 flows via the aperture 75 via the

N lower air guide bore 74 and emanating from this lower air guide groove 75 flows a. into the exhaust port 50 via preferentially a plurality of air guide bores 76 extending = 25 —inradial direction in the region of the valve seat ring 73, wherein because of this = exhaust gas is pushed out of the exhaust port 64 on the one hand and the valve

E body 67 of the gas exchange valve 62 on the exhaust side can be air-cooled on & the other hand.

R

&

As is best evident from Fig. 4a, the air, namely charge air, can be supplied to the upper air guide groove 74 of the valve seat ring 73 of the gas exchange valve 62 via an air guide bore 77 of the cylinder head 61 emanating from the inlet port 65.

While in the exemplary embodiments of Figs. 2a to 2c and 3a to 3c the valve seat rings 26 and 46 respectively are water-cooled as usual in the prior art, this is not the case in the exemplary embodiment of Figs. 4a, 4b. Accordingly, in Figs. 4a, 4b the valve seat ring 73 of the shown gas exchange valve 62 on the exhaust side is not water-cooled. However, the valve seat ring 72 of the gas exchange valve 63 on the inlet side can be water-cooled. Accordingly, in the exemplary embodiment of Figs. 4a, 4b, charge air is branched off the inlet port 65 of the gas exchange valve 63 on the inlet side and conducted in the direction of the valve seat ring 73 of the gas exchange valve 62 on the exhaust side. The charge air flows via the bore 77 into the region of the air guide grooves 74 of the valve seat ring 73 and via the air guide bore 76 into the exhaust port 64 adjacent to the valve body 67. The air flows over surfaces of the valve body 67 cooling the same. Exhaust gas is pushed out of the exhaust port 64.

A further exemplary embodiment of an internal combustion engine according to the invention is shown by Figs. 5a, 5b, wherein the exemplary embodiment of

Figs. 5a, 5b substantially corresponds to the exemplary embodiment of Figs. 4a, 4b, so that for avoiding unnecessary repetitions same reference numbers are used e for same assemblies and reference is made to the above explanations regarding

S these assemblies. In the following, only such details by which the exemplary

N 25 embodiment of Figs. 5a, 5b differs from the exemplary embodiment of Figs. 4a, 4b 2 are discussed for the exemplary embodiment of Figs. 5a, 5b. In the exemplary = embodiment of Figs. 5a, 5b, air, emanating from the inlet chamber 65 via the bore a 77 of the cylinder head 61 can be supplied to an air guide groove 74 of the valve 5 seat ring /3, wherein however in Figs. 5a, 5b in contrast with the exemplary = 30 embodiment of Figs. 4a, 4b this air conducted into the region of the air guide © groove 74 is not conducted into a further groove of the valve seat ring 73 but rather flows via a gap 74 between the valve seat ring 73 and the cylinder head 61 into the exhaust port 64. Since this gap 78 is spaced from the valve body 67, the charge air branched off the inlet chamber 65 serves primarily for the air-flushing of the exhaust port 64 in the exemplary embodiment of Figs. 5a, 5b and not for cooling the valve body 67 as in the exemplary embodiment of Figs. 4a, 4b.

While in the exemplary embodiment of Figs. 4a, 4b the valve seat ring 73 is exclusively air-cooled, the valve seat ring 73 in the region of the air guide groove 74 is air-cooled and in the region of the cooling water groove 79 water-cooled in the exemplary embodiment of Figs. 5a, 5b, so that in the exemplary embodiment of Figs. 5a, 5b a hybrid cooling of the valve seat ring 73 is ensured. In Figs. 2a to 3b, the respective seat rings 26, 46 are water-cooled as is usual in the prior art.

With all exemplary embodiments, an effective cooling in particular of the gas exchange valves of an internal combustion engine on the exhaust side is possible.

The invention is employed in particular with diesel engines, in particular with direct-injecting large internal combustion diesel engines as are employed on ships. e]

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List of reference numbers 1 Internal combustion engine 2 Cylinder head 3 Gas exchange valve 4 Gas exchange valve 5 Valve stem 6 Valve body 7 Valve guide 8 Valve seat ring 9 Section 10 Valve seat 11 Inlet port 12 Exhaust port 13 Spring element

Internal combustion engine 21 Cylinder head 22 Gas exchange valve 20 23 Valve stem 24 Valve guide

N 25 28 Section

S 29 Valve seat

S 30 Exhaust port

E 31 Air guide bore

N 32 Air guide bore 5 30 33 Groove > 34 Air guide bore

Air guide bore 36 Air guide bore

37 Inlet port 40 Internal combustion engine 41 Cylinder head 42 Gas exchange valve 43 Valve stem 44 Valve guide 45 Valve body 46 Valve seat ring 47 Spring element 48 Section 49 Valve sat 50 Exhaust port 51 Air guide bore 52 Gap 54 Groove 55 Inlet port 56 Air guide bore 57 Air passage 60 Internal combustion engine 61 Cylinder head 62 Gas exchange valve 63 Gas exchange valve 64 Exhaust port 65 Inlet port

S 25 66 Valve stem

S 67 Valve body 2 68 Valve guide

I 69 Valve stem

N 70 Valve body = 30 71 Valve guide = 72 Valve seat ring

N 73 Valve seat ring 74 Air guide groove

75 Aperture 76 Air guide bore 77 Air guide bore 78 Gap 79 Cooling water groove e]

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Claims

1. An internal combustion engine (40), with a cylinder head (41); with at least one cylinder; wherein in the cylinder head (41) for each cylinder at least one gas exchange valve for charge air on the inlet side each and at least one gas exchange valve (42) for exhaust gas on the exhaust side each is received; wherein each gas exchange valve comprises a valve stem (43) mounted in a valve guide (44), which carries a valve body (45) and a valve seat ring (46) interacting with the valve body (45); wherein the cylinder head (41) for each cylinder comprises an inlet port (55) for charge air interacting with the respective gas exchange valve on the inlet side and an exhaust port (50) for exhaust gas interacting with the receptive gas exchange valve (42) on the exhaust side; characterized in that the exhaust port (50) interacting with the respective gas exchange valve (42) on the exhaust side is air-flushed, an air passage (57) is formed on an outer surface of the respective valve guide (44), the air passage (57) being able to be supplied with air from a charge air supply or compressed-air supply, a gap (52) is formed in a lower section of the valve guide (44) and between the respective valve guide (44) and the respective valve stem (43), N at least one air guide bore (51) communicating the air passage (57) to N 25 the gap (52) is introduced in the respective valve guide (44), S via the gap (52) between the respective valve guide (44) and the S respective valve stem (43), the respective exhaust port (50) is air-flushed. T

~

2. The internal combustion engine according to claim 1, characterized in that N 30 the exhaust port (50) interacting with the respective gas exchange valve (42)

on the exhaust side is flushed with charge air which can be branched off a charge air supply of the internal combustion engine.

3. The internal combustion engine according to claim 1, characterized in that the exhaust port (50) interacting with the respective gas exchange valve (42) on the exhaust side is flushed with compressed air, which can be provided by a separate compressed-air supply of the internal combustion engine.

4. The internal combustion engine according to any of the claims 1 to 3, characterized in that the air guide bore (51) and the air passage (57) communicate via at least one groove (54) formed on an outer surface of the respective valve guide (44).

5. The internal combustion engine according to any of the claims 1 to 4, characterized in that the air guide bore (51) of the valve guide (44) introduced into the respective valve guide (44) communicates with an inlet port (55) for charge air of the respective cylinder via a bore (56) in the cylinder head (41).

6. The internal combustion engine according to any of the claims 1 to 5, N 20 characterized in that a plurality of the air guide bores (51) are introduced in & the respective valve guide (44), and that the air guide bores (51) are slanted o both with respect to the axial direction and with respect to the radial direction z: so that they converge in a direction facing the valve body (45). O o S 25

7. The internal combustion engine according to any one of the claims 1 to 6, characterized in that the valve seat ring (46) comprises at least one cooling water groove.

e] N O N N S O O I a a N 0 K LO N O N