Large-Bore Internal Combustion Engine

Abstract

Large-bore internal combustion engine (10), having a cylinder crankcase (13), having at least one cylinder bank (12) having a plurality of cylinders (11), each cylinder having a cylinder liner (14) and its own cylinder head (15) with at least one inlet valve (16) for charge air, with at least one outlet valve (17) for exhaust gas and with at least one injector (19) forfuel or an external ignition Device (spark plug, pre-chamber with spark plug, etc.) / having a valve train having at least one camshaft and a valve control which cooperates with the or each camshaft and transmits the control contour of the camshaft to the inlet valves (16) and the outlet valves (17), wherein a continuous support (18) that receives, at least in certain regions, the cylinder liners (14) of the cylinders of the respective cylinder bank, the cylinder heads (15) of the cylinders of the respective cylinder bank and, for each cylinder bank (12), an inlet camshaft (20) and an outlet camshaft (11) extends over all cylinders (11) of the respective cylinder bank (12) in the region of the or each cylinder bank (12).

Description

Large-Bore Internal Combustion Engine The invention relates to a large-bore internal combustion engine.

[0001] The invention relates to the area of so-called large-bore engines and large-bore internal combustion engines, the cylinders of which have a piston diameter of more than 130 mm, in particular of more than 175 mm. An example of such large-bore internal combustion engines is provided by marine diesel internal combustion engines. A large-bore internal combustion engine has a cylinder crankcase inside which a crankshaft is guided. Furthermore, a large-bore internal combustion engine has a plurality of cylinders forming at least one cylinder bank. Each cylinder of a large-bore internal combustion engine has a cylinder liner inside the cylinder crankcase, as well as its own cylinder head. The cylinder head of each cylinder has at least one inlet valve for charge air, at least one outlet valve for exhaust gas and at least one injector for fuel.

[0002] Because a large-bore internal combustion engine uses a separate cylinder head for each cylinder, due to the dimensions of its cylinders and the thermal expansion which arises in the region of the cylinders during operation, it is customary in the case of large-bore internal combustion engines to use a valve train håving at least one bottom-mounted camshaft, with the or each bottom-mounted camshaft as well as the crankshaft being guided inside the cylinder crankcase. The control of the gas exchange valves of the cylinders, which is determined by cams of the camshaft, is transmitted from the camshaft to the gas exchange valves over a valve control which cooperates with the respective camshaft, a valve train with a bottom-mounted camshaft being known from DE 10 2004 057 438 Al. Such a valve train has swing arms, valve push rods and rocker arms to transmit the control of the gas exchange valves determined by the cams to the latter.

[0003] To reduce exhaust gas emissions in large-bore internal combustion engines, more precision in the valve control times on the gas exchange valves is desired. However, it is difficult to provide more precise valve control times with valve trains that use bottom-mounted camshafts.

[0004] On this basis, it is the object of the invention to provide a novel large-bore internal combustion engine.

[0005] This object is achieved by a large-bore internal combustion engine according to claim 1. According to the invention, a continuous support that receives, at least in certain regions, the cylinder liners of the cylinders of the respective cylinder bank, the cylinder heads of the cylinders of the respective cylinder bank and, for each cylinder bank, an inlet camshaft with inlet cams and an outlet camshaft with outlet cams extends over all cylinders of the respective cylinder bank in the region of the or each cylinder bank.

[0006] With the present invention, for a large-bore internal combustion engine the cylinders of which have separate cylinder heads, it is proposed for the first time to use a valve train with overhead camshafts, wherein the inlet camshaft and the outlet camshaft for each cylinder bank of the large-bore internal combustion engine is mounted in the support, which extends continuously over all cylinders of the respective cylinder bank and furthermore receives, at least in certain regions, and guides, at least in certain regions, the cylinder liner and the cylinder head for each cylinder.

[0007] With the present invention, it is possible to provide more precision in the valve control times for each cylinder in a large-bore internal combustion engine håving separate cylinder heads and thus to reduce exhaust gas emissions.

[0008] According to an advantageous development, the respective support extends above the cylinder crankcase and is connected thereto. This enables the camshafts of the internal combustion engine to be mounted precisely and the rigidity of the internal combustion engine to be increased.

[0009] According to a further advantageous development, rocker arms on the inlet side and rocker arms on the outlet side are mounted on the respective support or the respective cylinder head. This enables the control determined by the cams to be advantageously transmitted to the gas exchange valves.

[0010] According to a further advantageous development, in the respective support there is a charge air pipe through which charge air can be fed to the cylinders, in particular to the cylinder heads of the cylinders received in the support, and / or an exhaust gas pipe through which exhaust gas can be discharged from the cylinders, in particular from the cylinder heads of the cylinders received in the support, and / or a cooling water supply pipe through which cooling water can be fed to the cylinders, in particular to the liners of the cylinders received in the support, and / or a cooling water discharge pipe through which cooling water can be discharged from the cylinders, in particular from the cylinder heads of the cylinders received in the support. Such an integration of functions in the support guiding the camshafts is particularly preferred in order to reduce the number of components.Charge air, exhaust gas and cooling water can be guided in a defined manner through the support in which the camshafts are mounted.

[0011] According to a further advantageous development, the liner and the cylinder head of each cylinder of the respective cylinder bank are sealed on the coolant side and / or the charge air side and / or the exhaust gas side from the respective support. Sealing of the support of the respective cylinder bank from the cylinder liners and cylinder heads received by the respective support is particularly preferred in order to connect the charge air pipe, exhaust gas pipe and cooling water line that are integrated in the support in a defined manner in the region of each cylinder to the respective cylinder liner and the respective cylinder head.

[0012] Preferred developments of the invention will become clear from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being restricted thereto, with reference to the drawing, in which: Fig. 1 shows a schematic cross-section through an internal combustion engine according to the invention; Fig. 2 shows a top view in viewing direction II; and Fig. 3 shows a side view in viewing direction III.

[0013] The invention relates to a large-bore internal combustion engine. The cylinders of such large-bore internal combustion engines have a piston diameter of more than 130 mm, in particular of more than 175 mm. Such a large-bore internal combustion engine can be a marine diesel internal combustion engine.

[0014] Fig. 1 shows a detail of an internal combustion engine 10 according to the invention in the region of a cylinder 11 of the internal combustion engine 10, the shown cylinder 11 being part of a cylinder bank 12 of the internal combustion engine 10. A plurality of cylinders 11 are placed behind each other or next to each other in the region of such a cylinder bank 12. In the case of an internal combustion engine in in-line arrangement, the internal combustion engine comprises one cylinder bank. In the case of an internal combustion engine in V arrangement, it comprises a plurality of, in particular two, cylinder banks which are arranged in a V shape relative to each other.

[0015] The internal combustion engine 10 of Fig. 1 comprises a cylinder crankcase 13 in which a crankshaft (not shown) is guided.

[0016] Each cylinder 11 of the internal combustion engine 10 has a cylinder liner 14 which serves to guide a cylinder piston (not shown) of the respective cylinder 11, the cylinder liner 14 protruding into the cylinder crankcase 13 in certain regions.

[0017] Each cylinder 11 has not only such a cylinder liner 14 but also a separate and individual cylinder head 15. The cylinder head 15 of each cylinder 11 comprises at least one inlet valve 16 for charge air, at least one outlet valve 17 for exhaust gas and at least one injector 19 for fuel, and optionally an external ignition device (spark plug, pre-chamber with spark plug, etc). The inlet valves 16 and outlet valves 17 of the cylinders 11 are gas exchange valves.

[0018] The internal combustion engine 10 according to the invention comprises, for each cylinder bank 12, a respective support 18 extending continuously over the entire cylinder bank 12 and hence all cylinders 11 of the respective cylinder bank 12. Here, according to Fig. 1, the support 18 receives the cylinder liner 14, in particular an upper portion 14a thereof, and the respective cylinder head 15 in the region of each cylinder 11.

[0019] The support 18 extending continuously over all cylinders 11 of the respective cylinder bank 12 is positioned above the cylinder crankcase 13 and connected thereto, for example by screwing.

[0020] The support 18 extending continuously over the respective cylinder bank 12 receives not only the upper portions 14a of the cylinder liners 14 of the cylinders 11 of the respective cylinder bank 12 and the cylinder heads 15 of the cylinders 11 of the respective cylinder bank 12 but also camshafts, in particular an inlet camshaft 20 to control the inlet valves 16 and an outlet camshaft 21 to control the outlet valves 17 of the cylinders 11 of the respective cylinder bank 12.

[0021] Accordingly, in the case of the large-bore internal combustion engine 10 according to the invention, camshafts 20, 21 that are received and guided inside the respective support 18 are used, in particular separate camshafts for the inlet valves 16 and the outlet valves 17, that is to say an inlet camshaft 20 and an outlet camshaft 21, which are not guided from below in the cylinder crankcase 13, but from above in the respective support 18 of the respective cylinder bank 12.

[0022] The control for the inlet valves 16 that is determined by the inlet camshaft 20 or the inlet cams of the inlet camshaft 20 can, in the exemplary embodiment shown, be transmitted to the inlet valve 16 by rocker arms 22 on the inlet side. Likewise, the control for the outlet valves 17 that is determined by the outlet camshaft 21 or the outlet cams of the outlet camshaft 21 can, in the exemplary embodiment shown, be transmitted to the outlet valves 17 by rocker arms 23 on the outlet side. Here, the rocker arms 22 on the inlet side and the rocker arms 23 on the outlet side are rotatably or tiltably mounted on the respective support 18 of the respective cylinder bank 12 or on the respective cylinder head 15.

[0023] The use of overhead camshafts 22, 23, in particular a separate inlet camshaft 22 and a separate outlet camshaft 23 for the inlet valves 16 and the outlet valves 17, and mounting these camshafts 22, 23 in the support 18, which receives the separate cylinder heads 15 of the cylinders 11 of the respective cylinder bank 12, enables the valve train to guarantee more precise valve control times for the gas exchange valves 16, 17 of the cylinders 11. More precise valve control times enable exhaust gas emissions to be reduced. The valve train has fewer components. This means that swing arms and valve push rods can be dispensed with. A further advantage is that the support 18 can increase the rigidity of the internal combustion engine in the power transmission chain from the camshafts in the direction of the gas exchange valves. This too enables more precise valve control times for the gas exchange valves 16, 17 of the cylinders 11 to be provided.

[0024] In the exemplary embodiment of the invention shown in Fig. 1, there is furthermore integrated in the support 18 of the respective cylinder bank 12, which extends continuously over all cylinders 11 of the cylinder bank 12, a charge air pipe 24 through which charge air can be fed to the cylinders 11, in particular the cylinder heads 15 of the cylinders 11 received in the support 18. Thus, Fig. 1 shows that the charge air pipe 24 integrated into the support 18 communicates with a charge air guide pipe 26 of the respective cylinder head 15 of the respective cylinder 11 through a corresponding recess 25, to supply the charge air guided from the charge air pipe 24 of the support 18 to the inlet valves 16 for charge air of the cylinders 11.

[0025] Furthermore, there is integrated in the respective support 18, which extends continuously over all cylinders 11 of the respective cylinder bank 12, an exhaust gas pipe 26 opposite the side of the support 18 in which the charge air pipe 24 is integrated. Here, the exhaust gas pipe 26 serves to discharge the exhaust gas from the cylinders 11 of the respective cylinder bank 12 that leaves the cylinders 11 of the respective cylinder bank 12 through their outlet valves 17. In the region of each cylinder 11 this exhaust gas pipe 26 communicates with an exhaust gas conveying duct 28 of the respective cylinder head by means of a corresponding opening 27.

[0026] In the preferred exemplary embodiment shown, not only the charge air pipe 24 and the exhaust gas pipe 26 but also a cooling water supply pipe 29 and a cooling water discharge pipe 30 are integrated into the respective support 18 of the respective cylinder bank 12.

[0027] The cooling water supply pipe 29 and the cooling water discharge pipe 30 are in this case preferably disposed on the same side of the support 18 as the exhaust gas pipe 26 provided therefrom.

[0028] As can be seen in Fig. 1, cooling water guided through the cooling water supply pipe 29 can be fed through a recess 31 in the support 18 to the cylinder liner 14, in particular to a lower cooling water annular chamber 32 which is delimited in certain regions by the upper portion 14a of the respective cylinder liner 14 and in certain regions by the respective support 18 of the respective cylinder bank 12. From this lower cooling water annular chamber 32, the cooling water can be fed through pipes 33 integrated in the cylinder liner 14, in particular in the upper portion 14a thereof, to an upper cooling water annular chamber 34 for cooling water, which is delimited in certain regions by the cylinder liner 14 and by the cylinder head 15 and also by the support 18.From this upper cooling water annular chamber 34, the cooling water can be guided through ducts (not shown) in the cylinder head 15 in the direction of a recess 35 in the respective support 18, which communicates with the cooling water discharge pipe 30 of the support 18.

[0029] In the preferred embodiment of the invention, the respective support 18 of the respective cylinder bank 12, which extends above the cylinder crankcase 13 over all cylinders 11 of the respective cylinder bank 12 and receives the cylinder liners 14 and the cylinder heads 15 of the cylinders 11 of the respective cylinder bank 12, at least in certain regions, assumes a multiplicity of functions, in particular the function of integrated charge air guidance, the function of integrated exhaust gas guidance, the function of integrated cooling water guidance and the function of mounting the camshafts 20, 21 and rocker arms 22, 23.

[0030] Fig. 1 also shows a multiplicity of seals, which serve to seal the liner 14 of the respective cylinder 11 and the cylinder head 15 of the respective cylinder 11 from the respective support 18 of the respective cylinder bank 12, these seals assuming the function of sealing on the coolant side and / or the charge air side and / or the exhaust gas side.

[0031] In this way, the charge air guided from the respective cylinder head 18, the exhaust gas guided therefrom and the cooling water guided therefrom can be fed to the respective cylinder head 15 and the respective cylinder liner 14 and discharged therefrom in a defined manner and without leakage.

[0032] Fig. 1 also shows a fuel pump 37 of the cylinder 11, which serves to supply the respective injector 19 with fuel, wherein the fuel can be fed to the respective injector 19 from the respective fuel pump 37 through a fuel pipe 36.

[0033] As can be seen in Fig. 1, the support 18, which extends continuously over all cylinders 11 of the respective cylinder bank 12 and which guides the inlet camshaft 20 and the outlet camshaft 21, is constructed to be open on the side in the region of the camshafts 20, 21 to facilitate access to the camshafts 20, 21, wherein corresponding openings 38, 39 for access to the camshafts 20, 21 are closed by cover plates 40, 41. In this regard, according to Fig. 3, there is an individual cover plate 40 in the region of each cylinder 11. It is also possible for a continuous cover plate 40 to extend over all cylinders 11.

Claims

1. A large-bore internal combustion engine (10),håving a cylinder crankcase (13),håving at least one cylinder bank (12) håving a plurality of cylinders (11), each cylinder håving a cylinder liner (14) and its own cylinder head (15) with at least one inlet valve (16) for charge air, with at least one outlet valve (17) for exhaust gas and with at least one injector (19) for fuel or optionally an external ignition device (spark plug, pre-chamber with spark plug, etc),håving a valve train håving at least one camshaft and a valve control which cooperates with the or each camshaft and transmits the control contour of the camshaft to the inlet valves (16) and the outlet valves (17), characterised in thata continuous support (18) that receives, at least in certain regions, the cylinder liners (14) of the cylinders of the respective cylinder bank, the cylinder heads (15) of the cylinders of the respective cylinder bank and, for each cylinder bank (12),an inlet camshaft (20) and an outlet camshaft (11) extends over all cylinders (11) of the respective cylinder bank (12) in the region of the or each cylinder bank (12)., 2. A large-bore internal combustion engine according to claim 1, characterised in that the respective support (18) extends above the cylinder crankcase (13) and is connected thereto.

3. A large-bore internal combustion engine according to claim 1-2, characterised in that rocker arms (22) on the inlet side and rocker arms (23) on the outlet side are mounted on the respective support (18) or the respective cylinder head (15).

4. A large-bore internal combustion engine according to any one of claims 1-3, characterised in that there is integrated in the respective support (18) a charge air pipe (24) through which charge air can be fed to the cylinders, in particular the cylinder heads (15) of the cylinders received in the support (18).

5. A large-bore internal combustion engine according to any one of claims 1-4, characterised in that there is integrated in the respective support (18) an exhaust gas pipe (26) through which exhaust gas can be discharged from the cylinders, in particular from the cylinder heads (15) of the cylinders received in the support (18).

6. A large-bore internal combustion engine according to any one of claims 1-5, characterised in that there is integrated in the respective support (18) a cooling water supply pipe (29) through which cooling water can be fed to the cylinders, in particular to the liners (14) of the cylinders received in the support (18).

7. A large-bore internal combustion engine according to any one of claims 1 -6, characterised in that there is integrated in the respective support (18) a cooling water discharge pipe (30) through which cooling water can be discharged from the cylinders, in particular from the cylinder heads (15) of the cylinders received in the support (18).

8. A large-bore internal combustion engine according to any one of claims 1-7, characterised in that the liner (14) and the cylinder head (15) of each cylinder are sealed on the coolant side and / or the charge air side and / or the exhaust gas side from to the respective support (18).