Patent Publication Number: US-2015059712-A1

Title: Charge air guide element and water ring element for internal combustion engine

Description:
TECHNICAL FIELD 
     The present disclosure generally refers to internal combustion engines and more particularly to charge air systems and cooling systems for internal combustion engines. 
     BACKGROUND 
     Medium speed internal combustion engines comprise a large amount of components. Some of those components are subject to service at, for example, components of cylinder unit such as the pistons. Besides physical wear, various components may further be subject to chemical active substances such as aggressive fuel and exhaust gas. 
     Internal combustion engines exhaust a complex mixture of air pollutants. These air pollutants are composed of gaseous compounds such as nitrogen oxides (NO X ), and solid particulate matter also known as soot. Due to increased environmental awareness, exhaust emission standards have become more stringent, and the amount of NO X  and soot emitted to the atmosphere by an engine may be regulated depending on the type of engine, size of engine, and/or class of engine. 
     In order to ensure compliance with the regulation of NO X , a strategy called exhaust gas recycling (EGR) for mixing the exhaust gas into the charge air may be implemented. EGR may reduce NO X  emission. As an exemplary EGR system, the EP application EP 2 218 896 A1 discloses a turbocharged engine with EGR. As another example, the EP application EP 2 333 292 A1 discloses a two-stage turbocharged engine with exhaust gas recycling using a specifically shaped mixing pipe configuration. 
     In addition to the conventional exhaust gas system, which is inherently subjected to any corrosiveness of the exhaust gas, an EGR system subjects also components of the charge air system to the corrosiveness of the exhaust gas by adding the corrosive exhaust gas to the charge air. 
     The large dimensions of medium speed internal combustion engines may result in large charge air systems and large exhaust gas systems of similar dimensions as the combustion engine. For example, charge air or exhaust gas pipes may extend along the sides of the internal combustion engines from one turbocharger to the other. Complex structures affect the serviceability of specific components of the engines. 
     Medium speed internal combustion engines may moreover be adapted for the use with fuels such as diesel fuel, light fuel oil (LFO), heavy fuel oil (HFO), alternative fuels of first generation biofuels (for example, palm oil, canola oil, oils based on animal fat) and second generation biofuels (for example, oils made of non food corps, i.e. waste biomass) that produce an exhaust gas that is destructive, for example, corrosive, to the components with which the exhaust gas gets in contact. 
     The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the present disclosure, a charge air guide element for an intake manifold of an internal combustion engine with a plurality of cylinder units may comprise a through flow section comprising a first passage fluidly connecting a front side of the charge air guide element with a back side of the charge air guide element and a supply section at a cylinder unit side of the through flow section that comprises a second passage fluidly connecting top side of the charge air guide element with the first passage. The charge air guide element may further comprise, integrated into a wall structure of the charge air guide element, a cooling water channel system that comprises at least one opening at the cylinder unit side of the through flow section, which opens towards the top side of the charge air guide element, and at least one opening at an access side of the charge air guide element, the access side being opposite to the cylinder unit side. 
     According to another aspect of the present disclosure, a water ring element for being mounted to an engine block of an internal combustion engine may comprise a cylinder liner section with a wall structure surrounding a through hole to provide a passage for a respective cylinder liner in a mounted state of the water ring element, and a cooling system for cooling the cylinder liner in the mounted state of the water ring element, wherein the cooling system may have a conduit structure with at least one opening at an outside of the wall structure that opens towards the engine block side of the water ring element. 
     According to another aspect, an internal combustion engine may comprise an engine block with a top side, a first end side, and a second end side, the second end side opposing the first end side, a plurality of cylinder units mounted at the top side and having cylinder liners reaching into the engine block, a charge air system comprising an inlet manifold for distributing charge air to each of the plurality of cylinder units, wherein the inlet manifold comprises a plurality of charge air guide elements as described above. The internal combustion engine may further comprise a plurality of water ring elements as described above, each mounted at the top side such that the at least one opening of the cooling system of each water ring element and the at least one opening of the cooling water channel system of the respective charge air element are fluidly connected. 
     In some embodiments of charge air guide elements, the cooling water channel system may comprises a supply channel and a return channel, each having an opening at the cylinder unit side of the through flow section, which opens essentially in the direction into which the second outlet opening opens. 
     In some embodiments, charge air guide elements may be one-piece cast parts. In addition or alternatively, water ring elements may be one-piece cast parts. 
     In some embodiments, a plurality of charge air guide elements may be configured to provide a fluid connection from an exit of a compressor stage to each of the cylinder units. 
     In general, an inlet manifold external to the engine block may provide good access and may be easy to mount, operate, and replace in comparison to an internal inlet manifold being integrated within the engine block. This applies in particular to an inlet manifold comprised of charge air guide elements. 
     For example, corrosion caused by exhaust gas supplemented to the charge air may cause damage components of the charge air system such as the charge air guide element of the inlet manifold. An exchange of a damaged component located at the outside may be easily serviced and may not affect the engine block, as, for example, air guide elements and mixing pipes may be formed as separate cast parts that then may be replaced if damaged. 
     Moreover, a configuration of a water ring element and a charge air guide element as described above may allow demounting the cylinder head and the water ring element for service purposes without the need of demounting the charge air system and the cooling water system. 
     Positioning of cooling water drainage ports at different positions may further simplify the replacement of a water ring element. 
     Configurations of charge air guide elements as disclosed herein may further allow implementing a charge air guide element for different configurations of internal combustion engines such as in-line configurations or V-configurations. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of an internal combustion engine in in-line configuration; 
         FIG. 2  is a schematic cut view of the internal combustion engine of  FIG. 1 ; 
         FIG. 3  is a schematic perspective view of a water ring element and a charge air guide element; 
         FIG. 4  is a schematic cut view of a water ring element, a charge air guide element, and cooling water pipes in the mounted state for an in-line configuration; 
         FIGS. 5 and 6  are further schematic perspective views of the charge air guide element of  FIG. 3 ; 
         FIG. 7  is a schematic cut view of a water ring element, a charge air guide element, and cooling water pipes in the mounted state for an in-line configuration; 
         FIG. 8  is a schematic illustration of the flow of charge air within the internal combustion engine of  FIG. 1 ; 
         FIG. 9  is a schematic perspective view of a further embodiment of a charge air guide element; and 
         FIG. 10  is a schematic cut view through the mounted state of the charge air guide element of  FIG. 9  and a water ring element. 
     
    
    
     DETAILED DESCRIPTION 
     The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the drawings are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of patent protection. Rather, the scope of patent protection shall be defined by the appended claims. 
     The present disclosure may be based in part on the realization that EGR may result in damages to the charge air system, which results in the potential requirement to ease replacement of damaged components of the charge air system. As a result, new configurations for medium speed internal combustion engines are disclosed that may improve accessibility of those components being affected by EGR and, in particular, allow the implementation of those affected components as replacement parts. 
     To reduce the affects of EGR, it was further realized that removing aggressive condensate may extend the lifetime of the affected components and that in particular a drainage system may be provided for the charge air guide elements. 
     Specifically, a charge air inlet manifold may be composed of modularized casted charge air guide elements each of which specifically interact with a respective water ring element. As the water ring element may need to be more often demounted for servicing the cylinder unit, a charge air guide element is proposed that may allow supplying cooling water to the water ring element and that may stay mounted while servicing the cylinder unit. 
     Moreover, it was realized that specific design choices allow applying the charge air guide elements for in-line engine configurations as well as V-configurations. Specifically, features such as mounts, cooling water drainage, and condensation drainage may be provided for various engine configurations such as in-line and V-configurations, resulting in an improved efficiency in design work and logistic of replacement parts. 
     In addition, the present disclosure discloses a mixing pipe for connecting a turbocharged system with an inlet manifold for implementing EGR in a compact manner. 
     Referring to  FIGS. 1 and 2 , an internal combustion engine  1  may comprise several cylinder units  16 A- 16 I arranged in-line. As an example,  FIG. 1  shows nine cylinder units. Internal combustion engine  1  may comprise an engine block  10  housing the crankshaft and providing support for cylinder units  16 A- 16 I being mounted thereon and reaching through cylinder openings at a top side  21  of engine block  10  into the inside of engine block  10 . Cylinder opening  11 B is shown in  FIG. 2 . 
     Internal combustion engine  1  may further comprise a two-stage turbocharged system  12  having a low-pressure stage turbocharger  26  and a high-pressure stage turbocharger  28 , which form a sequential turbocharging system. Generally, turbochargers may be applied to use the heat and pressure of the exhaust gas of an engine to drive a compressor for compressing the charge air for the engine. Internal combustion engine  1  may further comprise a fuel tank, one ore more catalyst systems, and an engine control unit, which are not shown. 
     Cylinder units  16 A- 16 I may each comprise a cylinder head part  17 , a combustion chamber, and a cylinder associated for guiding a piston within a cylinder liner. The piston may be connected to the crankshaft. As indicated in  FIG. 2A , a cover  17 C may cover and protect the top of cylinder head part  17  as well as mechanical parts and fluid connection parts being arranged thereon. Internal components of cylinder units  16 A- 16 I are not shown in detail. 
     In addition to top side  21 , engine block  10  may have end sides  18 L and  18 H, being opposite in a lengthwise direction  19  defined by the longitudinal arrangement of cylinder units  16 A- 16 I. Engine block  10  may further have opposing long sides  20 A,  20 B being opposite in a direction orthogonal to lengthwise direction  19 . Cylinder units  16 A- 16 I may linearly be arranged between end sides  18 L and  18 H and parallel to long sides  20 A,  20 B. 
     Internal combustion engine  1  may comprise a charge air system, which includes, for example, an intake manifold  22 , and an exhaust gas system, which includes, for example, an exhaust manifold  24 . For EGR, a fluid connection  36  between the exhaust gas system and the charge air system may be provided such that in a controlled manner exhaust gas can be mixed with the charge air before charging the combustion chamber. In  FIG. 1 , fluid connection  36  may leak into a mixing pipe  29  that may be provided before the charge air enters intake manifold  22 . Moreover, there may be an inlet for adding an additive (for example water) to the pre-compressed charge air within the charge air system. 
     Intake manifold  22  may extend on top of top side  21  in lengthwise direction  19  and may be fluidly connected to each of cylinder units  16 A- 16 I. Accordingly, top side  21  may be configured for mounting charge air inlet manifold  22 , specifically, its components as explained below, thereon. Top side  21  may be free of any charge air openings that would provide a fluid connection from a fluid charge air passage  34  within the engine block to intake manifold  22 . 
     Intake manifold  22  may be connected to high-pressure turbocharger  28  via mixing pipe  29  and to inlet openings of cylinder units  16 A- 16 I. Each of cylinder units  16 A- 16 I may be provided with at least one inlet valve (not shown) configured to open or close the fluid connection between intake manifold  22  and the combustion chamber of the respective cylinder unit. 
     Intake manifold  22  is separate from engine block  10  and may be comprised of a sequence of separately configured charge air guide elements  23 A- 23 I that are mounted at top side  21 . For example, top side  21  may comprise screw holes for mounting the charge air guide elements  23 A- 23 I thereon. As disclosed below, some of those screw holes may extend orthogonally into top side  21 , while some screw holes may extend into engine block under an angle unequal 90° with respect to top side  21 . 
     Charge air guide elements  23 A- 23 I may be configured as separate parts to allow piecewise assembly of individual cylinder units. Moreover, the specific configuration described herein may allow servicing a cylinder unit such as cylinder liner, piston, valves, etc. without removing the respective charge air guide element. 
     As shown in  FIG. 2 , exhaust manifold  24  may be provided above intake manifold  22 . For example, sections of exhaust manifold  24  may be attached to charge air elements by schematically indicated mounts  25 . Exhaust manifold  24 , for example, each section, may be fluidly connected to each of cylinder units  16 A- 16 I. Each of cylinder units  16 A- 16 I may include an exhaust valve (not shown) configured to open and close the fluid connection between the combustion chamber of a respective cylinder unit  16 A- 16 I and exhaust manifold  24 . 
     Generally, when internal combustion engine  1  is operated, combustion chambers may be charged with charge air provided via intake manifold  22 . After combustion, exhaust gas generated by the combustion process may be released from cylinder units  16 A- 16 I via exhaust manifold  24 . 
     As shown in  FIG. 1 , low-pressure stage turbocharger  26  may comprise a compressor C L  and a turbine T L  that are mechanically connected via a common shaft. Similarly, high-pressure stage turbocharger  28  may comprise a compressor C H  and a turbine T H  that are connected via a common shaft. An inlet of compressor C L  may be configured to suck in charge air for the combustion process. Generally, an outlet of compressor C L  may be fluidly connected via a compressor connection  34  with an inlet of compressor C H . 
     At end side  18 L (also referred to as low-pressure side), low-pressure stage turbocharger  26  may be fixedly attached to engine block  10 , for example directly or as a unit in combination with other components such as a charge air coolant block, for example a first cooler  30  etc. 
     At end side  18 H (also referred to as high-pressure side), high-pressure stage turbocharger  28  may be fixedly attached to engine block  10 , for example directly or as a unit in combination with other components such as a charge air coolant block, for example a second cooler  32  etc. 
     By mounting the turbochargers  26 ,  28  at opposite sides of engine block  10 , mounting may be simplified and space may be used effectively, while providing easy access to the engine&#39;s components from long sides  20 A,  20 B and from the top. 
     Compressor connection  34  may provide a passage from end side  18 L to end side  18 H within the one-piece casted engine block  10  but is otherwise closed air tight. As shown in  FIG. 2 , compressor connection  34  may be a duct system integrated into casted engine block  10 , which may be configured to withstand a charge air pressure of at least 3, 4, or 5 bar. In the case of a medium speed large internal combustion engine, compressor connection  34  may have a length of several meters, for example 5m. 
     The outlet of compressor C L  may be connected via first cooler  30  to compressor connection  34 . An outlet of compressor C H  may be connected via second cooler  32  and mixing pipe  29  with intake manifold  22 . 
     During operation of engine  1 , the charge air may be twice compressed and cooled before charging of the combustion chambers of cylinder units  16 A- 16 I. For example, for medium speed large internal combustion engines, compressor C L  may compress the charge air to 3-5 bar at 180° C. Cooler  30  may cool the charge air from about 180° C. to 45° C. Compressor C H  may compress the charge air to 7-8 bar at 180° C. and cooler  32  may cool the charge air from about 180° C. to 45° C. 
     The cooling may result in condensation within the charge air system and its components. In particular with EGR or various types of fuels, the condensate may become chemically reactive and, in particular, may affect the wall structure of the charge air systems in regions where a condensate may accumulate. As disclosed herein, the charge air guide elements may be provided with specific drainage ports to remove the aggressive condensate from the charge air system. 
     Within the combustion chambers, further compression of the charge air may be caused through the movement of the pistons. At the end of the compression cycle, an appropriate amount of fuel such as diesel oil, marine diesel oil, heavy fuel oil, alternative fuels, or a mixture thereof, may be injected into the combustion chambers. The fuel may be combusted with the compressed charged air and produce exhaust gas, which may be discharged via exhaust manifold  24 . 
     An outlet of exhaust manifold  24  may be connected to an inlet of turbine T H . An outlet of turbine T H  may be fluidly connected with an inlet of turbine T L  via turbine pipe connection  35  and an outlet of turbine T L  may release the exhaust gas. The exhaust gas system may additionally comprise one or more catalyst systems and/or one or more exhaust gas filtering systems that may be arranged, for example, externally or within turbine pipe connection  35 . 
     The above described operation of internal combustion engine  1  may provide power to turn the crankshaft, for example, to drive a generator. 
     Referring to  FIG. 1 , intake manifold  22  may be provided externally to engine block  10  and may be made of a sequence of charge air guide elements  23 A- 23 I for guiding charge air from high-pressure stage turbocharger  28  to each of cylinder units  16 A- 16 I. Charge air guide elements  23 A- 23 I may be made as cast parts that are mounted on top of engine block  10  with, for example, four screws. Neighbouring charge air guide elements may be fluidly connected via plain conduits to distribute the charge air, supplied to a first one of the charge air guide elements  23 A- 23 I to downstream positioned charge air guide elements. 
       FIGS. 3 and 4  illustrate a charge air guide element  23  and its interaction with a water ring element  40 . Specifically,  FIG. 3  shows a perspective view of an exemplary charge air guide element  23  for mounting together with a water ring element  40  onto engine block  10  in a not-assembled state. In a cut view,  FIG. 4  shows then charge air guide element  23  and water ring element  40  mounted to engine block  10 . Charge air guide element  23  and water ring element  40  may each be made as a cast part. 
     Water ring element  40  may comprise a valve drive feed trough section  41  and a water ring section  42  for providing cooling water to the cylinder liner of the respective cylinder unit. Valve drive feed trough section  40  may comprise an opening  43 B for having drive stems for operating the valves extending there through. Water ring element  40  may be the basis for mounting cylinder head part  17  thereon. A control air through hole  43 C may further be integrated in the wall structure of water ring element  40  to provide pressurized control air to cylinder head part  17 . 
     Water ring element  40  may comprise six screw guiding holes  43 A that are arranged around water ring section  42  and extend within its wall structure, for example, in direction of the cylinder axis. For each cylinder unit  16 A- 16 I, top side  21  of engine block  10  may have six tap holes surrounding a piston opening. Mounting water ring element  40  together with the respective cylinder unit (not shown in  FIG. 4 ) onto top side  21  of engine block  10  may be done, for example, using screws passing through the screw guiding holes  43 A. 
     In in-line configuration, top side  21  of engine block  10  may comprise a series of piston openings linearly arranged in the direction from first end side  18 L to second end side  18 H, while in V-configuration, the top side may include, for each of the two cylinder banks, a top section that is tilted with respect to the other and comprises a series of piston openings linearly arranged. 
     In the mounted state, a cylinder liner may reach from a respective cylinder head part  17  through the respective water ring section  42  and further through top side  21  into engine block  10 . 
     Water ring section  42  may be configured for guiding coolant (for example, cooling water of a high temperature cooling circuit of the engine) around the cylinder liner and towards cylinder head  17  for cooling the cylinder liner and cylinder head during operation of the engine. In the mounted state, water ring section  42  may surround the respective cylinder liner such that a gap exists between water ring section  42  and the cylinder liner, which forms a water path around the cylinder liner. 
     Water ring element  40  may comprise cooling water connections for receiving cooling water from and returning cooling water to charge air guide element  23 . As shown in  FIG. 4 , a supply connection  44 A may extend through the wall structure of water ring section  42 . Supply connection  44 A may be formed at an outside of the wall structure in a tab-like structure such that a water inlet opening is formed to open towards the engine block side of water ring  40 . 
     The cooling water, which circulated around the cylinder liner and was guided upwards into the cylinder head, may be returned from the cylinder head into a return connection  44 B. Return connection  44 B may comprise a channel  44 C extending within the wall structure, for example, in direction of the cylinder axis. Return connection  44 B may form, at an outside of the wall structure, a tab-like structure such that a water outlet opening is formed to open towards the engine block side of water ring  40 . The tab-like structure of return connection  44 B may be positioned next to the tab-like structure of supply connection  44 A. 
     As the water connections are directed downwards towards the engine block side of water ring  40 , they may be connectable, for example, via sealing inserts  47  to counterpart water connections of cooling water channels of charge air guide element  23  described below. 
     Charge air guide element  23  may comprise an air channel system inside. Specifically, charge air guide element  23  may comprise an inlet opening  45 A on a first side of charge air guide element  23 , a first outlet opening  45 B at a second side being opposite to the first side, thereby providing a fluid connection (first passage  48 A) from the first side to the second side (specifically, to first outlet opening  45 B) in lengthwise direction  19  when mounted on top side  21 . 
     As illustrated above with reference to  FIG. 1 , neighbouring charge air guide systems  23 A- 23 I may be fluidly connected, thereby linearly extending the fluid connections of the sequence of charge air guide elements  23 A- 23 I and form intake manifold  22 . 
     Referring again to  FIG. 3 , each charge air guide element  23  may further comprise a second outlet opening  45 C that may be fluidly connected to first passage  48 A, thereby providing a fluid connection (second passage  48 B) from the first side to the second outlet opening  45 C. Second outlet opening  45 C may be positioned at a water ring side of charge air guide element  23  and may be configured for providing a charge air connection to a charge air inlet of the respective cylinder unit. 
     Referring to  FIG. 2 , cylinder head part  17  may comprise a first tube-like extension  17 A and a second tube-like extension  17 B. First tube-like extension  17 A may form the charge air inlet of the cylinder unit and connect to second outlet opening  45 C of the respective charge air guide element  23 . Second tube-like extension  17 B may form the exhaust gas outlet of cylinder head part  17  and connect to exhaust manifold  24 . 
     Integrated in its wall structure, charge air guide element  23  may comprise cooling water channels for fluidly connecting cooling water pipes  70  (shown in  FIG. 4 ) of a cooling system with the cooling water connections of water ring element  40 . Specifically, in the mounted state, a supply channel  50 A may fluidly connect the supply pipe with the water inlet opening of supply connection  44 A and a return channel  50 B may fluidly connect the return pipe with the water outlet opening of return connection  44 B. 
     Supply channel  50 A and return channel  50 B may extend within the wall structure of charge air guide element  23 . At the water ring side, supply channel  50 A and return channel  50 B may each comprise an opening  52  opening in the same direction as opening  45 C (in the mounted state in a direction away from engine block  10 ) such that, for example, when sealing inserts  47  are positioned within openings  51 , water ring element  40  may be lowered onto engine block  10  and a water tight connection between supply connection  44 A and supply channel  50 A as well as between return connection  44 B and return channel  50 B may be established. Similarly, water ring element  40  may be removed without demounting charge air guide element  23 . 
     Within the wall structure of charge air guide element  23 , supply channel  50 A and return channel  50 B may extend for about 180° around passage  48 A, at first along the engine block side and then along an access side (opposite to the water ring side). 
     At the upper portion of the access side, there may be provided two pairs of openings for establishing a fluid connection to cooling water pipes. The openings may open in a direction that allows access in dependence of the type of engine configuration. For example, one pair of openings for in-line configuration may open in direction away from the engine in horizontal direction and one pair of openings for V-configuration may open in direction away from the engine in vertical direction as explained in detail with reference to  FIGS. 5 and 6 . 
     For each pair, the openings may be positioned next to each other in axial direction of passage  48 A, in the mounted state along length direction  19 . 
     As shown in  FIG. 5 , openings  60 A for in-line configuration may open at the access side, while openings  60 B for V-configuration may open at the top side of charge air guide element  23 . Tap holes  61  may be provided at both sides of the pairs for attaching a connecting pipe element  49  for connecting to cooling water pipes  70  as shown in  FIG. 4 . 
     Next to the two pairs of openings, a mounting surface  62  with tab holes  61  may be provided for mounting a holder such as holder  25  in  FIG. 2  to hold exhaust manifold  24 . 
     Referring to  FIGS. 5 and 6 , the cooling water channels of charge air guide element  23  may further comprise cooling water drainage ports, for example, cooling water drainage ports  52 A in a central part of the cooling water channels and cooling water drainage ports  52 B at the water ring side opening, for example, in a direction into which opening  45 A opens. As understood by the skilled person, cooling water drainage ports  52 A,  52 B may be closed directly at charge air guide element  23  to close the cooling circuit during operation. Alternatively, the closing may be performed at some distance when a drainage pipe is connected to cooling water drainage ports  52 A,  52 B. 
     Cooling water drainage ports  52 A may further allow curing the cooling water channels after the casting. For example, the cooling water channels may be casted to have two sections extending essentially linearly from the cooling water drainage ports  52 A. 
     In some embodiments, condensate drainage ports may be provided to fluidly connect first passage  48 A with the outside at positions in which condensate may accumulate during operation. For example, condensate a drainage port  54 A may be positioned next to cooling water drainage ports  52 B and connect to the inside for removing condensate when charge air guide element  23  is mounted at an in-line configured engine. For V-configuration, a condensate drainage port  54 B may be positioned below openings  45 B and connect to the inside for removing condensate when charge air guide element  23  is mounted at a V-configured engine (see  FIG. 6 ). 
     Charge air guide element  23  may be mounted via four screws inserted into screw guiding holes. For example, charge air guide element  23  may comprise at the water ring side, two screw guiding holes  64 A that are directed essentially orthogonally towards the engine block side. Charge air guide element  23  may further comprise two screw guiding holes  64 B at the access side, which may be positioned under an angle with respect to screw guiding holes  64 A. Respective tap holes extending orthogonal to top side  21  and an angle of, for example, 70° to top side  21  may be provided in engine block  10 . 
     The angle may be selected in accordance with the V-configuration for which the charge air guide element may be used. For example, V-configuration with two cylinder banks may be characterized by the tilt angle between the bank sections of the engine block top side. In some embodiments, a horizontal transition side  21 A may connect the bank sections. 
     When a charge air guide element  23  is mounted to an engine in V-configuration, screw guiding holes  64 A may be orthogonally directed onto each bank section (not shown in  FIG. 7 ) and screw guiding holes  64 B may be orthogonally directed onto horizontal transition section  21 A of V-engine block  10 A. 
     As exemplarily shown in  FIG. 7 , a block  66  may be attached, for example screwed, to horizontal transition side  21 A to bridge the space between screw guiding holes  64 B and engine block  10 A. The angled orientation of screw guiding holes  64 A and screw guiding holes  64 B may allow accessing the screws when using charge air guide element  23  with in-line and V-configured engines. 
     The outer shapes of water ring  40  and charge air guide element  23  may be configured such that water ring  40  may be removed and mounted without the need of demounting charge air guide element  23  for in-line and V-configurations. 
     As an example,  FIG. 8  illustrates schematically the flow of charge air in an charge air system. From compressor C L , which may suck in charge air from the outside, charge air may pass cooler  30  and compressor connection  34  before being further compressed by compressor C H . From compressor C H , charge air may pass cooler  32  and mixing pipe  29  before being distributed by intake manifold  22  to the cylinder units. Intake manifold  22  may be composed of charge air guide elements  23 . Specifically, charge air guide elements  23  may be connected to respective charge air inlets  17 A of cylinder head parts of cylinder units  16 A- 16 I. 
     Mixing pipe  29  may be fluidly connected via a valve (not shown) with fluid connection  36  for connecting the charge air system with the exhaust gas system. Thereby, exhaust gas may be mixed with charge air in a controlled manner before being distributed to the combustion chambers via inlet manifold  22 . 
     Mixing pipe  29  may also comprise a condensate drainage located at the lowest point when mounted between high pressure cooler  32  and intake manifold  22 . 
     In general, the various drainage ports may be connected to a common drainage system ensuring proper draining under various operating conditions that occur, for example, in marine applications. 
       FIGS. 9 and 10  illustrate an alternative embodiment of a charge air guide element  123  and its interaction with a water ring element  140 . Specifically,  FIG. 9  shows a perspective view of charge air guide element  123  and  FIG. 10  illustrates the coolant flow in a cut view through the mounted state of charge air guide element  123  and water ring element  140 . In the following not all features will be described in detail. However, the skilled person will understood in connection with the first embodiment that features of the various embodiments may be similarly applied to the other embodiment, such as charge air guide element  123  and water ring element  140  may each be made as a cast part and drainage ports for the cooling system as well as the air system may be provided and using clamped or bolted flanges. 
     Charge air guide element  123  comprises an air channel system inside. Specifically, charge air guide element  123  comprises an inlet opening  145 A on a first side of charge air guide element  123 , a first outlet opening  145 B at a second side being opposite to the first side, thereby providing a fluid connection (first passage  148 A) from the first side to the second side (specifically, to first outlet opening  145 B) in lengthwise direction  19  when mounted on the top side of an engine block. 
     As illustrated above with reference to  FIG. 1 , neighbouring charge air guide systems may be fluidly connected, thereby linearly extending the fluid connections of the sequence of charge air guide elements and form intake manifold  22 . In the embodiment of  FIG. 9 , a bolted flange configuration is indicated by screw threads in contrast to the clamp configuration of  FIG. 3 . 
     Referring again to  FIG. 9 , each charge air guide element  123  further comprises a second outlet opening  145 C fluidly connected to first passage  148 A, thereby providing a fluid connection (second passage  48 B) from the first side to second outlet opening  145 C respectively mounted to each cylinder unit. As shown in  FIG. 10 , second outlet opening  145 C is positioned at a water ring side of charge air guide element  123 . 
     Integrated in its wall structure, charge air guide element  123  comprises a pair of cooling water channels connected to a connecting pipe element  49  (shown in  FIG. 4 ) for fluidly connecting cooling water pipes  70  (shown in  FIG. 4 ) with the cooling water connections of water ring element  140 . 
     Specifically, in the mounted state, a supply channel  150 A extends from an supply inlet opening  160 Bs to a supply outlet opening  151   s  and a return channel  150 B extends from a return inlet opening  151   r  to a return outlet opening  160 Br. Supply inlet opening  160 Bs, supply outlet opening  151   s , return inlet opening  151   r , and return outlet opening  160 Br open essentially in the direction into which the second passage  148 B of the supply section opens at the top side of charge air guide element  123 . The essentially identical orientation of supply inlet opening  160 Bs, supply outlet opening  151   s , return inlet opening  151   r , return outlet opening  160 Br, and second outlet opening  145 C simplifies the assembly and demounting of water ring element  140  and charge air guide element  123  as well as the providing of a simple cooling water circuit to and from the cooling water pipes. 
     In other words, supply channel  150 A fluidly connects the cooling water pipe with a water inlet opening  144 As of supply connection  144 A, for example, configured in a tap-like manner and a return channel  150 B fluidly connects the return pipe with a water outlet opening  144 Br of return connection  144 B. 
     Supply channel  150 A and return channel  150 B extend within the wall structure of charge air guide element  123 . Within the wall structure of charge air guide element  123 , supply channel  150 A and return channel  150 B may extend for about 180° around passage  148 A, at first along the engine block side and then along an access side (which is opposite to the water ring side). 
     In contrast to the embodiment of  FIG. 3 , only one pair of openings  160 Bs,  160 Br for in-line configuration and V-configuration open in direction away from the engine in horizontal direction, thereby further simplifying the cooling channel system, for example, open at the top side of charge air guide element  123 . Further mounting surfaces  162  are provided for mounting a holder to hold, for example, an exhaust manifold. 
     Cooling water channels  150 A and  15 B of charge air guide element  123  may further comprise cooling water drainage ports, for example, cooling water drainage ports  152 A in a central part of the cooling water channels and cooling water drainage ports (not shown) at the water ring side opening, for example, in a direction into which opening  145 A opens. As understood by the skilled person, the cooling water drainage ports can be sealed to close the cooling circuit during operation. 
     In some embodiments, condensate drainage ports may be provided to fluidly connect first passage  148 A with the outside at positions in which condensate may accumulate during operation. For example, a condensate drainage port  154 A next to cooling water drainage ports  152 A connects to the inside for removing condensate when charge air guide element  123  is mounted at an in-line configured engine. For V-configuration, a condensate drainage port may be provided as disclosed in connection with  FIG. 6 . 
     It is referred to  FIGS. 6 and 7  and the respective description also for the screw guiding holes that are directed essentially orthogonally towards the engine block side and screw guiding holes  164 B at the access side, which may be positioned under an angle with respect to screw guiding holes. 
     The outer shapes of water ring element  140  and charge air guide element  123  may be configured such that water ring element  140  may be removed and mounted without the need of demounting charge air guide element  123  for in-line and V-configurations. 
     Referring to  FIG. 10 , exemplarily the return path of the cooling water from the cylinder unit to the water pipes is illustrated. 
     From the cylinder head (not shown), the cooling water enters a cooling water return conduit  144 B through an return conduit opening  244 Br at the top of water ring element  140 . The top is configured as, for example, a cylinder head interface. Cooling water return conduit  144 B extends essentially axially along the wall of water ring element  140  and forms a tab-like structure that comprises water outlet opening  144 Br. A sealed connection to return channel  150 B is provided by a sealing insert  147  fitted into return conduit opening  244 Br and return inlet opening  151   r . Return channel  150 B extends at the bottom of charge air element  123  from the water ring side to the access side and then bends upwards to the top side of charge air element  123  to open into return outlet opening  160 Br. Prior bending towards return outlet opening  160 Br, a, for example, straight connection to cooling water drainage port  152 A is provided. The return flow is indicated by arrows  200 . 
     The cooling water supply is essentially configured in a similar manner, with the difference, that supply connection  144 A opens into the inside of water ring element  140 . 
     INDUSTRIAL APPLICABILITY 
     Herein, the term “internal combustion engine” may refer to internal combustion engines which may be used as main or auxiliary engines of stationary power providing systems such as power plants for production of heat and/or electricity as well as in ships/vessels such as cruiser liners, cargo ships, container ships, and tankers. Fuels for internal combustion engines may include diesel oil, marine diesel oil, heavy fuel oil, alternative fuels or a mixture thereof, and natural gas. 
     In addition, the term “internal combustion engine” as used herein is not specifically restricted and comprises any engine, in which the combustion of a fuel occurs with an oxidizer to produce high temperature and pressure gases, which are directly applied to a movable component of the engine, such as pistons or turbine blades, and move it over a distance thereby generating mechanical energy. Thus, as used herein, the term “internal combustion engine” comprises piston engines and turbines. 
     Examples of internal combustion engines for the herein disclosed configuration of a two-stage turbocharged system include medium speed internal combustion diesel engines, like inline and V-type engines of the series M20, M25, M32, M43 manufactured by Caterpillar Motoren GmbH &amp; Co. KG, Kiel, Germany, operated in a range of 500 to 1000 rpm. 
     Medium speed internal combustion engines may be large stand-alone engines that therefore provide reasonable access to the end sides of the engine block. 
     Herein a fluid connection generally may correspond to a component providing a fluid connection, for example, via an internal pathway having at least two openings connected by a side wall, such as for example a pipe. Components providing fluid pathways of the charge air system and the exhaust gas system may be connected with each other, for example, by flange connections as indicated in some of the figures. 
     In some embodiments, neighbouring charge air guide elements may be fluidly connected via a conduct, for example, a plain conduits or bellow. 
     Moreover, the mounting aspect and the aspect of the cooling channel system are independently of each other addable to charge air guiding elements. 
     The design of the charge air guide elements and water ring elements as disclosed herein may be applicable to single or multistage turbocharged engines. 
     Moreover, the charge air guide element may comprise each of the aspect of cooling channels integrated in its wall structure and the aspect of the mounting using angled mounting channels separately or in combination. 
     Although the preferred embodiments of this invention have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.