Abstract:
The invention relates to a V engine ( 1 ), especially a diesel engine, comprising a first cylinder bank ( 2 ) and a second cylinder bank ( 3 ), said V engine being designed for two-stage charging by means of a low-pressure exhaust gas turbocharger ( 4, 5 ) and a high-pressure exhaust gas turbocharger ( 6, 7 ). The invention is characterised in that the low-pressure exhaust gas turbocharger ( 4, 5 ) and the high-pressure exhaust gas turbocharger ( 6, 7 ) are respectively arranged on the front of a cylinder bank ( 2, 3 ) above a main output element ( 23 ) of the V engine ( 1 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application 10 2009 052 209.3 filed on Nov. 6, 2009 and PCT/EP2010/006719 filed on Nov. 4, 2010, which are hereby incorporated by reference in their entireties. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a V engine. 
       BACKGROUND 
       [0003]    Forced induction for internal combustion engines, including high performance internal combustion engines, is known in the prior art, wherein the forced induction is carried out by means of mechanical superchargers or exhaust stream turbochargers. Such engines are, for example, diesel engines, such as ship power plant engines or industrial engines, for example, having an output in the range of several hundred kW, for example. In this case, forced induction systems with one exhaust stream turbocharger per block of cylinders are known, as in EP 0 952 329 A2, for example, as are forced induction systems having multi-stage charging, with multiple turbochargers per cylinder bank, for example. 
         [0004]    In addition, in the field of such high-performance internal combustion engines, stricter exhaust regulations will require compliance in the future. In order to meet emission specifications and/or requirements, including for example the EPA TIER  4  rule for emissions, an internal combustion engine of the type presently considered must be designed in accordance with the rules using emission-reducing technologies, for example. Typically, such technologies require significant constructed space. 
         [0005]    Proceeding from the above situation, the problem addressed by the invention is that of suggesting a low-emission engine, particularly an engine in the output range above 500 kW, which overcomes the disadvantages named above, and which enables an extremely compact construction, particularly by means of the arrangement of the forced induction system. 
       SUMMARY 
       [0006]    According to the disclosure, a V engine is suggested, particularly a diesel engine, having a first and a second cylinder bank, wherein the V engine is designed for two-stage forced induction by means of a low-pressure exhaust stream turbocharger, as well as a high-pressure exhaust stream turbocharger, wherein one low-pressure exhaust stream turbocharger and one high-pressure exhaust stream turbocharger are arranged on the end face of each of the two cylinder banks above a primary output element of the V engine. 
         [0007]    In one embodiment, the V engine has a low-pressure compressor in each of a first and a second charge air line, for the purpose of directing a charge air stream, a charge air cooler, and a high-pressure compressor, wherein one low-pressure compressor is arranged in each low-pressure exhaust stream turbocharger, and one high-pressure compressor is arranged in each high-pressure exhaust stream turbocharger, and wherein the first and the second charge air streams are merged at a primary charge air cooler, wherein one charge air stream is directed downstream from the primary charge air cooler to each of the first and second cylinder banks, and wherein the configuration includes one exhaust gas return per cylinder bank, and each exhaust gas return has one exhaust gas return cooler. By means of this exhaust gas return, cooled exhaust gas of each cylinder bank can be inserted into the charge air stream to the same cylinder bank downstream from the primary charge air cooler. 
         [0008]    In a further embodiment, the V engine has one exhaust gas return cooler arranged above a cylinder head on each cylinder bank. 
         [0009]    In a further embodiment of the V engine, an intermediate charge air cooler is provided on each cylinder bank, and is arranged in each case between the exhaust gas return cooler situated on the cylinder bank and the low-pressure and high-pressure exhaust stream turbochargers arranged on the end face of the cylinder banks. 
         [0010]    In addition, in one embodiment of the V engine, a primary charge air cooler is arranged between the exhaust gas return coolers arranged above one cylinder head on each cylinder bank, and is particularly arranged between the flanks of the V-shape of the V engine. 
         [0011]    According to a further embodiment of the V engine, exhaust gas from each cylinder bank, particularly cooled exhaust gas, is injected by means of a mixer element into a charge air stream downstream from the primary charge air cooler. 
         [0012]    According to the disclosure, a V engine is suggested wherein the mixer element is arranged on an end face of the primary charge air cooler which faces away from the primary output element. 
         [0013]    In one aspect of the V engine, the exhaust gas return coolers and/or the high-pressure exhaust stream turbochargers and/or the low-pressure exhaust stream turbochargers and/or the primary charge air coolers and/or the intermediate charge air coolers are arranged symmetrically about a center axis A of the V engine. 
         [0014]    In one embodiment of the V engine, the low-pressure exhaust stream turbocharger and the high-pressure exhaust stream turbocharger are arranged on a power output side of the V engine. 
         [0015]    In a further embodiment of the V engine, the low-pressure compressors of the first and the second low-pressure exhaust stream turbocharger are connected by a vacuum housing arranged between the same. 
         [0016]    According to a further embodiment of the V engine, one low-pressure exhaust stream turbocharger is connected in series with one high-pressure exhaust stream turbocharger and arranged on each cylinder bank, particularly on an end face thereof. 
         [0017]    Additional features and advantages of the disclosure are found in the description of embodiments of the disclosure given below, with reference to the illustrated figures showing essential aspects of the disclosure, and in the claims. The individual features can be incorporated individually or in any and all combinations to realize a variant of the disclosure. 
         [0018]    Preferred embodiments of the invention are described in greater detail below with reference to the attached illustrations, wherein: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows an exemplary charge air- and exhaust stream flow diagram in a V engine according to one possible embodiment of the disclosure; 
           [0020]      FIG. 2  shows an exemplary illustration of the V engine in a frontal view, according to one possible embodiment of the disclosure; 
           [0021]      FIG. 3  shows an exemplary illustration of the V engine in  FIG. 2  in a top view; 
           [0022]      FIG. 4  shows an exemplary illustration of the V engine in  FIG. 2  in a side view. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the following description, elements having the same or comparable functions are indicated by identical reference numbers. 
         [0024]    In order to enable a compact constructed shape of an internal combustion engine, a V engine  1  is provided (for example as in  FIG. 1 ,  2 ). Compared to an inline motor, for example, the V engine  1  generally has a shorter length and is suitable for realizing a compact constructed shape. In the known manner, the V engine  1 , which is a diesel engine or a gasoline engine, for example, has a first  2  and a second  3  cylinder bank, wherein the cylinder banks can assume an angle of the V which theoretically lies anywhere from 1 to 180 degrees, and for example is a V angle of 90 degrees. The V engine  1 , for example an engine with a high output above 500 kW, has an arrangement which is used to increased performance, and particularly to increase performance in a controllable manner, by means of forced induction (charging). Particularly, a two-stage charger is included, for example a regulated two-stage charger, wherein, by way of example, an exhaust stream is first directed at each of two first high-pressure exhaust stream turbochargers, for example, and then to the low-pressure exhaust stream turbochargers, for example. The regulation thereof in this case can be carried out via a conventional bypass, for example. 
         [0025]    According to the disclosure, the V engine  1  is turbocharged in two stages by means of a first  4  and a second  5  low-pressure exhaust stream turbocharger, as well as by means of a first  6  and a second  7  high-pressure exhaust stream turbocharger. To this end, by way of example, the first low-pressure exhaust stream turbocharger  4  and the first high-pressure exhaust stream turbocharger  6  are arranged on the first cylinder bank  2 , and the second low-pressure exhaust stream turbocharger  5  and the second high-pressure exhaust stream turbocharger  7  are arranged on the second cylinder bank  3 , in such a manner that initially two charge air lines  8  and/or  9  are formed, and the same can be merged downstream to create a single charge air line. The first exhaust stream turbochargers  4 ,  6 , and the second exhaust stream turbochargers  5 ,  7  in this case are each driven solely by the exhaust stream of the cylinder bank  2 ,  3  to which they are functionally assigned, for example, and are each driven by means of the turbine wheels thereof arranged in the exhaust stream thereof, for example. 
         [0026]    A low-pressure compressor  10  in each of the low-pressure exhaust gas turbochargers  4  and  5  can be driven in the known manner my means of such a turbine wheel, as can a high-pressure compressor  11  in each of the high-pressure exhaust stream turbochargers  6 ,  7 . 
         [0027]    According to the disclosure, one low-pressure exhaust stream turbocharger  4 ,  5  is connected in series to one high-pressure exhaust stream turbocharger  6 ,  7  on each of the cylinder banks  2 ,  3  as part of the two-stage turbocharging configuration, meaning that an exhaust stream proceeds from the respective cylinder bank  2 ,  3 , for example, and initially flows through the high-pressure exhaust stream turbocharger  6  and/or  7 , for example, driving the same, to then flow to the low-pressure exhaust stream turbocharger  4  and/or  5 , driving the same. As such, in each case, one high-pressure exhaust stream turbocharger  6  and/or  7  and one low-pressure exhaust stream turbocharger  4  and/or  5  are connected in series as regards their (driven) turbines and/or the incoming flow thereof; i.e. they are connected in a drive series. 
         [0028]    For the purpose of complying with strict exhaust gas regulations, for example, including EPA TIER  4   i  or EPA TIER  4  final, for example, the V engine  1  has, as part of the included two-stage, and particularly regulated, turbocharger system, an exhaust gas return system in addition to the exhaust stream turbochargers  4 ,  5 ,  6 ,  7 , for example, wherein said exhaust gas return system has an exhaust gas return cooler, an intermediate charge air cooler, and a primary charge air cooler. An exemplary arrangement, of such a system in conjunction with the (engine) turbocharging is described below, with reference to  FIG. 1 . 
         [0029]    The V engine  1  has, as indicated above, a first  8  and a second  9  charge air (line) section, each of which is included in the configuration for the purpose of directing the charge air  12  in the direction of (the combustion chambers of) a cylinder bank  2 ,  3 . Components for cooling and compressing the charge air  12  are arranged in each of the charge air line sections  8 ,  9 . In the present case, each charge air section  8  and  9  has a low-pressure compressor  10  on the inlet and/or intake side thereof, for example a low-pressure exhaust stream turbocharger  4  and/or  5  for each. The charge air pre-compressed by means of a low-pressure compressor  10  is supplied to an intermediate charge air cooler  13  arranged downstream (with respect to the flow direction toward a cylinder bank  2 ,  3 ), and is further compressed and/or densified by means of a high-pressure compressor  11 , for example a high-pressure exhaust stream turbocharger  6  and/or  7 , in each section. 
         [0030]    The charge air  12  of the first  8  and the second  9  charge air lines, having been compressed in this manner, is merged and cooled again by means of a primary charge air cooler  14  arranged downstream. The cooling by means of the intermediate charge air cooler  13  and the primary charge air cooler  14  achieves a low- and/or reduced nitric oxide combustion by reducing the combustion temperature in a combustion chamber. 
         [0031]    The charge air  12  cooled by means of the primary charge air cooler  14  is divided downstream of the primary charge air cooler  14  into a first  15  and a second  16  (partial) charge air stream, each of which is directed to a cylinder bank  2 ,  3  (each having, for example, 3 or more cylinders  2   a  and/or  3   a ) for use in the combustion. The exhaust gas  17  created in each of the cylinder banks  2 ,  3  as part of the combustion process is directed, by means of an exhaust gas return system  18 , into the fractional first  15  and/or second  16  (partial) charge air streams, for example, wherein the latter connect with the primary charge air cooler  14  downstream of the same, for the purpose of adjusting the combustion temperature to achieve a low-emission combustion, for example. A configuration can also be contemplated wherein the exhaust gas  17  is directed into a unified charge air stream prior to the separation into partial charge air streams. 
         [0032]    The exhaust gas returns  18  are each designed as a bypass, for example, and each have one, and for example exactly one, exhaust gas return cooler  19  for the purpose of reducing the exhaust gas temperature, thereby also reducing the combustion temperature as a result of the exhaust gas, the same having being cooled as such, being introduced into the first or second charge air stream  15  and/or  16 , whereby the ejection of nitric oxide can also be further reduced. The exhaust gas return cooler  19  is a known exhaust gas return cooler, for example, having a stainless steel cooling element, for example, which provides cooling by means of cooling water, for example. 
         [0033]    To make it possible to implement the V engine  1  with the intended compact dimensions, the low-pressure exhaust stream turbochargers  4  and  5 , as well as the high-pressure exhaust stream turbochargers  6  and  7  are arranged on the end faces of the cylinder banks  2 ,  3  of the V engine  1 , particularly each on the end faces of the cylinder banks  2 ,  3  on the same side of the V engine  1 , and particularly on the power output side  20 , for example, where a primary output element  23  is arranged. In this case, the term ‘end face’ indicates an outer end of the V engine  1  and/or of the cylinder bank  2 ,  3  in the direction of the neighboring cylinders ( 2   a ,  3   a ) of one cylinder bank  2  and/or  3  (in the x-dimension). 
         [0034]    In this case, the arrangement is implemented in such a manner, for example, that one low-pressure exhaust stream turbocharger  4  and/or  5  is arranged together with one high-pressure exhaust stream turbocharger  6  and/or  7  on the end face of each of the cylinder banks  2  and/or  3 . In each case, one low-pressure exhaust stream turbocharger  4  and/or  5  is arranged in series with one high-pressure exhaust stream turbocharger  6  and/or  7 , for example. 
         [0035]    In this configuration, one low-pressure exhaust stream turbocharger  4  and/or  5  and one high-pressure exhaust stream turbocharger  6  and/or  7  are arranged on each cylinder bank  2 ,  3 , in each case on the upper end of the V engine  1 , for example, and at the height of the cylinder heads  25 , for example, along with further components for the turbocharging, for example, including an intake and/or charge air inlet housing  21 , wherein the latter can be arranged between the low-pressure compressors  10  of the first  4  and the second  5  low-pressure exhaust stream turbochargers, conduits and/or connector pipes  22 , pressure cartridges, etc. 
         [0036]    The low-pressure exhaust stream turbochargers  4 ,  5  as well as the high-pressure exhaust stream turbochargers  6 ,  7  in this case are particularly arranged above the primary output element  23 , wherein the same can consists of a flywheel  23   a  of the V engine  1 , for example. This means that the exhaust stream turbochargers [4, 5, 6, 7] are arranged above the primary output element  23  with respect to the direction proceeding from an oil pan  24  towards the cylinder head  25  (the z-dimension). The term ‘primary output element  23 ’ in this case indicates the element which is provided for the purpose of transmitting the majority of the engine energy to an element being driven (a shaft, flywheel, etc.). By means of such an arrangement, components arranged on the side  26  opposite the output (the fan side), including the oil filter, fuel filter, etc., for example, remain accessible, thereby increasing the ease of servicing of the engine. 
         [0037]    In addition, for the purpose of realizing the compact dimensions of the V engine  1 , an exhaust gas return cooler  19 , and for example exactly one exhaust gas return cooler  19  at each position, is included in the configuration above one cylinder head  25  of each cylinder bank  2 ,  3 . The exhaust gas return coolers  19  are particularly each arranged in such a manner that an installation space is formed and/or created between an end of an exhaust gas return cooler  19 , wherein said end faces the exhaust stream turbochargers  4 ,  6  and/or  5 ,  7 , and the exhaust stream turbochargers  4 ,  6  and/or  5 ,  7  themselves, and this installation space enables the accommodation and/or arrangement of an intermediate charge air cooler  13 . As such, an intermediate charge air cooler  13  is arranged on and/or above (in the z-dimension) each cylinder bank  2 ,  3  between an exhaust gas return cooler  19  and a high-pressure and low-pressure exhaust stream turbocharger  4 ,  6  and  5 ,  7 , for example between the same in the direction from the output side  20  to its opposite side (in the x-dimension). 
         [0038]    According to the disclosure, in one configuration, particularly intended for the purpose of achieving a compactly constructed, space-saving arrangement of the pipes, wherein the same are used for directing the charge air, for example, the exhaust gas return coolers  19  are each arranged with the longitudinal axis A thereof oriented along the x-dimension, in such a manner that connectors  19   a  for the exhaust stream delivery and/or exhaust stream discharge are arranged in the direction pointing toward the output side of the engine and/or the opposite side, and preferably the direction pointing toward the opposite side, for example, and are each also arranged on an end face  27 , for example, of the exhaust gas return cooler  19 . In addition, in this configuration, and for the same purpose, the intermediate charge air coolers  13  are each, for example, arranged in such a manner that each connector  13   a  for a high-pressure and/or low-pressure compressor  11  and/or  10 , the same being arranged on an end face  28 , for example, is displaced by 90 degrees with respect to the x- and z-dimensions (aligned with the y-dimension). 
         [0039]    In addition, for the purpose of realizing an extremely compact and low-emission V engine  1 , a primary charge air cooler  14 , particularly exactly one primary charge air cooler  14 , for example, is arranged between the first  2  and the second  3  cylinder bank, for example between the flanks of the V in the V-shape formed by the cylinder banks  2 ,  3 . The primary charge air cooler  14  is particularly arranged between the exhaust gas return coolers  19  of the first and the second cylinder bank, meaning between the same  19  along the imaginary line extending from the first cylinder bank  2  to the second cylinder bank  3  (the y −  dimension). Also for the purpose of achieving a compact engine arrangement of the V engine  1 , charge air inlets and outlets  14   a  of the primary charge air cooler  14  are likewise arranged in the x-dimension, for example, such that air can flow to the primary charge air cooler  14  from the engine output side  20 , for example, and the charge air is removed in the direction opposite the engine output  26 , for example. As such, conduit elements for the routing of charge air can likewise be arranged between the cylinder banks  2 ,  3  and therefore incorporated into an arrangement with a small constructed space. 
         [0040]    According to the disclosure, for the purpose of mixing or adding to the exhaust gas returned by means of each of the exhaust gas returns  18 , using the charge air stream  12  and/or  15 ,  16 , and/or mixing/adding thereto (using up to 60% of the total exhaust gas, for example), a mixer element is included downstream of the primary charge air cooler  14 , for example, in the form of a mixer housing  29 , for example, and exactly one mixer housing  29 , for example. Such a mixer housing  29  allows the regulated dosing and/or mixing of the exhaust gas  17  to/with the compressed charge air. The mixer housing  29  is arranged on a side facing away from the exhaust stream turbochargers,  4 ,  5 ,  6 ,  7 , for example, the same being an end face  30  (on the side opposite the engine output), for example, of the primary charge air cooler  14 , and likewise between the flanks of the V-shape, for example, of the first  2  and the second  3  cylinder banks, for example. The mixer housing  29  is also intended, for example, to divide the charge air stream  12  merged at the primary charge air cooler  14  to form both the first  15  and the second  16  charge air streams for the two cylinder banks  2 ,  3 . The mixer housing  29  is arranged in such a manner, for example, that the connectors  29   a  thereof which serve to take in and/or discharge the charge air are oriented substantially along the x-dimension, wherein the connectors for the discharge of the charge air are oriented in the direction facing opposite the engine output side, for example. 
         [0041]    With the arrangement of the components included for the forced induction and/or for the purpose of reducing emissions, it is possible to realize an extremely compact V engine  1 . For example, it is possible to realize a construction wherein the ratio of the engine length in the x-dimension, with the exhaust stream turbochargers  4 ,  5 ,  6 ,  7 , to the length of the engine block L itself is smaller than a factor of 1.4 ( FIG. 4 ). In this case, the arrangement of the exhaust stream turbochargers  4 ,  5 ,  6 ,  7  and/or the exhaust gas return coolers  19  and/or the intermediate charge air coolers  13  and/or the primary charge air coolers  14  is also symmetric to a center axis B of the V engine  1 , as seen in the x-dimension. In the configuration, pairs of exhaust gas return coolers  19 , intermediate charge air coolers  13 , and/or exhaust stream turbochargers  4 ,  5  and/or  6 ,  7  are situated opposite each other along the B axis, for example. 
         [0042]    With the arrangement of the exhaust stream turbochargers  4 ,  5 ,  6 ,  7  on the end face of the cylinder banks  2 ,  3  and above the primary output element  23  of the V engine  1 , it is possible to prevent a compromise to the functionality and accessibility of the primary output element  23 , as long as the primary output element  23  and the exhaust stream turbochargers  4 ,  5 ,  6 ,  7  do not overlap each other in the y-dimension and in the z-dimension.