Patent Publication Number: US-8973538-B2

Title: Inline engine having side-mounted heat exchangers

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to an engine and, more particularly, to an inline engine having side-mounted heat exchangers. 
     BACKGROUND 
     Engines, including diesel engines, gasoline engines, and gaseous fuel-powered engines, typically combust a fuel/air mixture to generate mechanical, hydraulic, or electrical power output. In order to ensure optimum combustion of the fuel/air mixture and simultaneously protect components of the engine from damaging extremes, temperatures of the engine and air drawn into the engine for combustion should be tightly controlled. For this reason, an internal combustion engine is generally fluidly connected to several different liquid-to-liquid, liquid-to-air, and/or air-to-air heat exchangers to cool both liquids and gases circulated throughout the engine. 
     One way of packaging heat exchangers on an inline marine engine is disclosed in U.S. Pat. No. 7,287,493 of Buck that issued on Oct. 30, 2007 (the &#39;493 patent). The engine of the &#39;493 patent is equipped with a turbocharger, a turbo jacket cooler, an intercooler, a jacket water heat exchanger, an engine oil cooler, a secondary fluid cooler (e.g., a transmission oil cooler), a primary water pump, and a raw water pump. The turbocharger is mounted at one end of the engine and outfitted with the turbo jacket cooler. The intercooler is mounted directly to cylinder heads of the engine on a side of the engine opposite from the jacket water heat exchanger. An engine oil cooler is mounted to a side of an engine block, below the jacket water heat exchanger. The secondary fluid cooler is located on a front end of the engine. The primary water pump is also located at the front end of the engine, while the raw water pump is mounted to the engine block at an end of the engine oil cooler below the jacket water heat exchanger. The raw water pump circulates sea water through the turbocharger cooling jacket, the intercooler, the jacket water heat exchanger, and the secondary cooler. The primary water pump circulates fresh water through the jacket water heat exchanger, the engine, and the oil cooler. 
     The disclosed engine is directed to overcoming one or more problems of the prior art. 
     SUMMARY 
     In one aspect, the present disclosure is directed to an engine. The engine may include an engine block with a front end, a back end opposite the front end in a length direction, a first side, a second side opposite the first side, a top, and a bottom opposite the top. The engine may also include at least one cylinder head connected to the top of the engine block, and a first heat exchanger mounted at the first side of the engine block and configured to receive a flow of raw coolant and a flow of fresh coolant. The engine may further include a second heat exchanger mounted at the first side of the engine block and configured to receive fresh coolant from the first heat exchanger and a flow of combustion air. 
     In another aspect, the present disclosure is directed to another engine. This engine may include an engine block having a front end, a back end opposite the front end, a first side, a second side opposite the first side, a top, and a bottom opposite the top. The engine may also include at least one cylinder head connected to the top of the engine block, a first heat exchanger mounted at the first side of the engine block and configured to receive a flow of raw coolant and a flow of fresh coolant, and a second heat exchanger mounted at the second side of the engine block and configured to receive a flow of raw coolant and a flow of fresh coolant. The engine may further include a raw coolant pump mounted at the second side of the engine block and having an inlet located at an elevation between the top of the engine block and the first and second heat exchangers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of an exemplary disclosed cooling system; 
         FIG. 2  is a left side view of an exemplary disclosed engine incorporating the cooling system of  FIG. 1 ; and 
         FIG. 3  is right side view of the engine of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary disclosed cooling system  10  associated with an inline internal combustion engine  12 , for example a diesel, gasoline, or gaseous fuel powered engine. Cooling system  10  may include a first circuit  14 , a second circuit  16 , and a third circuit  18 . Fluid flows may be regulated through the different circuits of cooling system  10  to regulate temperatures of engine  12 . 
     First circuit  14  may be a raw coolant circuit. In the exemplary embodiment, engine  12  is a marine engine and, for the purposes of this disclosure, the term raw coolant may be considered a coolant taken from the environment of engine  12 , for example sea water. Raw coolant may be drawn by a raw coolant pump  20  into first circuit  14  via an inlet  22 . Raw coolant pump  20  may circulate raw coolant through a passage  100  to an aftercooler heat exchanger (AC hex)  24  and then through a passage  110  to a jacket water heat exchanger (JW Hex)  26 . After exiting JW hex  26 , the raw coolant may be directed through a passage  120  to a secondary heat exchanger, for example a transmission oil cooler (TOC)  28 , before discharge back to the environment via an outlet  30 . 
     Second circuit  16  may be a fresh coolant circuit configured to transfer heat from engine  12  to the raw coolant of first circuit  14 . For the purposes of this disclosure, the term fresh coolant may be considered a coolant kept onboard engine  12  in a closed circuit, typically water or a water/glycol mixture. Second circuit  16  may include a pump  32  that circulates the fresh coolant of second circuit  16  through AC hex  24  where heat may be transferred from the fresh coolant to the raw coolant. After exiting AC hex  24 , the fresh coolant may circulate through a passage  130  to a thermostat (T-stat)  34  and then to an expansion tank  36  located just upstream of pump  32 . Pump  32  may be connected to expansion tank  36  via a passage  135 . From pump  32 , the fresh coolant may be circulated through a passage  140  to a secondary heat exchanger, for example a fuel cooler (FC)  38 , and through a passage  150  to a charge air cooler (CAC)  40  where heat may be transferred from combustion air entering engine  12  to the fresh coolant. By locating FC  38  upstream of CAC  40 , FC  38  may experience low coolant temperatures without significantly affecting operation of CAC  40 . The fresh coolant may circulate from CAC  40  through a passage  160  to AC hex  24  and then to expansion tank  36  via passage  130  and T-stat  34 . Alternatively, the coolant may bypass AC hex  24  and flow from CAC  40  directly to T-stat  34  via a passage  165  and, if desired. 
     Third circuit  18  may also be a fresh coolant circuit configured to transfer heat from engine  12  to the raw coolant of first circuit  14 . Third circuit  18  may include a pump  42  that circulates the fresh coolant of third circuit  18  through JW hex  26  where heat may be transferred from the fresh coolant to the raw coolant. After exiting JW hex  26 , the fresh coolant may circulate through a passage  170  to a thermostat (T-stat)  44  and then to an expansion tank  46  located just upstream of pump  42 . Pump  42  may be connected to expansion tank  46  via a passage  180 . From pump  42 , the fresh coolant may be circulated through a passage  190  to a secondary heat exchanger, for example an engine oil cooler (EOC)  48 , before being directed through a passage  200  into engine  12 . A parallel flow of fresh coolant may also flow from EOC  48  through a passage  210  to a turbocharger  50  before being directed through a passage  220  into engine  12 . After exiting engine  12 , the fresh coolant may flow through a passage  230  to JW hex  26  and then back to expansion tank  46  via T-stat  44 . Alternatively, the fresh coolant from engine  12  may bypass JW hex  26  and flow directly to T-stat  44  via a passage  240 , if desired. By locating EOC  48  upstream of engine  12 , EOC  48  may experience low coolant temperatures without significantly affecting cooling of engine  12 . 
     Each of pumps  20 ,  32 , and  42  may be engine-driven to generate the flows of coolant described above. In particular, pumps  20 ,  32 , and  42  may each include an impeller (not shown) disposed within a volute housing having an inlet and an outlet. As the coolant enters the volute housing, blades of the impeller may be rotated by operation of engine  12  to push against the coolant, thereby circulating the coolant through cooling system  10 . An input torque imparted by engine  12  to pumps  20 ,  32 , and  42  may be related to a pressure of the coolant, while a speed imparted to pumps  20 ,  32 , and  42  may be related to a flow rate of the coolant. It is contemplated that pumps  20 ,  32 , and  42  may alternatively embody piston type pumps, if desired, and may have a variable or constant displacement. 
     Each of AC hex  24 , JW hex  26 , TOC  28 , FC  38 , and EOC  48  may be a liquid-to-liquid type heat exchanger configured transfer heat either from the fresh coolant to the raw coolant or from another operating fluid (e.g., oil, fuel, etc.) to the fresh coolant. For example, AC hex  24 , JW hex  26 , TOC  28 , FC  38 , and EOC  48  may each embody a flat-plate heat exchanger or a tube-and-bundle heat exchanger. As a primary flow of fluid passes through the respective heat exchanger, it may conduct heat through internal walls of the heat exchanger to a secondary flow of fluid also passing through the heat exchanger. It is contemplated that the primary and secondary flows of fluid may be parallel flows, opposite flows, or cross flows, as desired. 
     CAC  40  may be a liquid-to-air heat exchanger configured to transfer heat from combustion air entering engine  12  to the fresh coolant of second circuit  16 . That is, a flow of charged air exiting turbocharger  50  may be directed through channels of CAC  40  such that heat from the coolant in adjacent channels is transferred to the air. In this manner, the combustion air entering engine  12  may be cooled to a desired operating temperature. 
     T-stats  34  and  44  may be used to regulate a temperature of the fresh coolant passing through second and third circuits  16 ,  18 , respectively. Specifically, in response to a desired temperature of the respective fresh coolant flows, valves (not shown) within T-stats  34 ,  44  may selectively move to restrict or even block fresh coolant from passing through AC and JW hexes  24 ,  26 . In this manner, the amount of heat transfer from the fresh coolant flows to the raw coolant may be controlled. 
     Turbocharger  50  may include a compressor side  51  and a turbine side  53  connected to each other by way of a shaft. Exhaust passing through turbine side  53  of turbocharger  50  may drive compressor side  51  via the shaft to pressurize combustion air. Compressor side  51  of turbocharger  50  may be located upstream of CAC  40  such that the pressurized combustion air is cooled prior to entering engine  12 . 
       FIGS. 2 and 3  illustrate physical locations of the components of cooling system  10  relative to engine  12 . As shown in these figures, engine  12  may include an engine block  52  having a front end  54 , a back end  56  opposite front end  54  in a length direction, a first side  58  (e.g., a right side shown  FIG. 2 ), a second side  60  (e.g., a left side shown in  FIG. 3 ) opposite first side  58  in a horizontal direction, a top  62 , and a bottom  64  opposite top  62  in a vertical direction. Engine  12  may also include at least one cylinder head  66  connected to top  62  of engine block  52 , a front housing  68  connected to front end  54 , and a back housing  70  connected to back end  56 . Cylinder head  66  may cap off one or more inline cylinders (i.e., cylinders aligned in the vertical direction of engine block  52 ) of engine  12  to at least partially define one or more combustion chambers (not shown). In the illustrated embodiment, a one-piece cylinder head  66  is shown as capping off three different cylinders to define three different combustion chambers, although any number of cylinder heads  66  may be utilized. Front housing  68  may facilitate a fly-wheeled connected to a transmission or generator (not shown). Back housing  70  may facilitate power distribution from a crankshaft (not shown) of engine  12  to engine-driven components, for example to pumps  20 ,  32 , and  42 . The components of cooling system  10 , as will be described in more detail below, may be mounted to engine block  52 , cylinder head  66 , front housing  68 , and back housing  70  in a manner that enhances operation of cooling system  10  and reduces packaging costs. 
     For example,  FIG. 2  shows raw coolant pump  20  as being mounted at first side  58  of engine block  52  and including inlet  22  fixedly connected to pump  20  and oriented downward toward bottom  64  of engine block  52 . A connection of pump  20  with inlet  22  (indicated by a + sign) may be located at about the intersection of top  62  and first side  58 . As will be described in more detail below, this location, in conjunction with an elevation of passage  110 , may help to retain raw coolant within the heat exchangers of cooling system  10 , even when engine  12  is non-operational. 
     AC hex  24 , T-stat  34 , expansion tank  36 , and FC  38  are shown in  FIG. 2  as also being mounted at first side  58 , near raw coolant pump  20 . In one embodiment, AC hex  24  may be mounted to have a length direction generally aligned with a length direction of engine block  54 , and be located forward of and nearer to bottom  64  than raw coolant pump  20  (i.e., located in the length direction of block  52  between raw coolant pump  20  and front end  54  and in the vertical direction between raw coolant pump  20  and bottom  64 ). T-stat  34  and expansion tank  36  may be located almost directly above coolant pump  20  (e.g., slightly more toward back end  56 ), while FC  38  may be mounted closer to back end  56  and bottom  64  of engine block  52  than AC hex  24 , but closer to front end  54  than raw coolant pump  20 . By locating AC hex  24  below inlet  22  of raw coolant pump  20  and below a high point of passage  110 , it may be ensured that AC hex  24  remains full of raw coolant, even when engine  12  is non-operational. When the engine components are full of coolant, oxygen in the air may have little affect on corrosion of the components. Further, by co-locating AC hex  24 , T-stat  34 , expansion tank  36 , FC  38 , and raw coolant pump  20  at first side  58 , plumbing between these components may be reduced (i.e., lengths of passages  130 - 165  may be reduced). 
     CAC  40  may be mounted to cylinder head  66  at first side  58  of engine block  52  to have a length direction generally aligned with a length direction of engine block  54 , in a location closer to front end  54  than to back end  56 . In one embodiment, CAC  40  may be located at about the same location in the length direction of engine block  52  as AC hex  24  (i.e., in general alignment along the length direction). By mounting CAC  40  to cylinder head  66  and by co-locating raw AC hex  24  and CAC  40  at first side  58 , plumbing between these components may be reduced. 
     Turbocharger  50  may be mounted at front end  54  of engine block  52 , with compressor side  51  oriented toward first side  58  of engine block  52  and turbine side  53  oriented toward second side  60 . In this manner, charged air exiting turbocharger  50  may be routed directly to CAC  40  via a short section of piping, thereby reducing an amount of heat dissipated from the charged air to a customer&#39;s engine room. Similarly, hot exhaust gas exiting engine  12  may be directed via a short section of exhaust manifold  74  to turbine side  53  of turbocharger  50 , also thereby reducing an amount of heat dissipated to the customer&#39;s engine room. 
       FIG. 3  shows JW hex  26  mounted at second side  60  of engine block  52  to have a length direction generally aligned with a length direction of engine block  54 , at a location below exhaust manifold  74  (i.e., between exhaust manifold  74  and bottom  64  of engine block  52 ) and further toward front end  54  than back end  56 . In one embodiment, JW hex  26  may be substantially identical to AC hex  24 , but mounted in an orientation different than that of AC hex  24 . In particular, a fresh water inlet  73  and a fresh water outlet  75  of JW hex  26  may be generally aligned in the horizontal direction of engine block  52  and located relatively close to engine block  52 , while a fresh water inlet  77  and a fresh water outlet  79  of AC hex  24  may be generally aligned in the vertical direction of engine block  52  and located further away from engine block  52 . Because JW hex  26  and AC hex  24  may be identical components, tooling required to fabricate these components may be reduced. In addition, the ability to mount JW hex  26  and AC hex  24  in different orientations may allow for mounting flexibility and improved use of space on engine  12 . The location of JW hex  26  low on engine block  52  (i.e., below the high point of passage  110 ), in conjunction with a relatively high outlet location of passage  120  (indicated by a “+” symbol) may help ensure that JW hex  26  remains full of raw coolant even when engine  12  is non-operational. Further, the location of JW hex  26  below exhaust manifold  74 , may help protect JW hex  26  from being damaged from above, for example by falling tools, parts, or debris. 
     EOC  48  may be located at second side  60 , below JW hex  26  and closer to back housing  70  than to front housing  68 . This low location on engine block  52  may help ensure that EOC  48  remains full of fresh coolant and oil, even when engine  12  is non-operational. 
     Because the heat exchangers of cooling system  10  may be mounted at the sides of engine  12  (i.e., to the sides of engine block  52  and cylinder head  66 ), the back end of engine  12  may be relatively free of cooling components and available for mounting other components. In the embodiment of  FIGS. 2 and 3 , serviceable components may be mounted to back housing  70 . For example one or more filters such as engine oil filters  76  or fuel filters  78  (shown only in  FIG. 2 ) may be mounted to back housing  70 . 
     Engine oil filters  76  may each include a base end  80  connected to back housing  70 , and a free distal end  82 . Engine oil filters  76  may be upside-down, such that free distal ends  82  extend upward away from base ends  80  and are gravitationally higher. The location of serviceable components on the back end of engine  12  may improve access to these components, while the upside-down orientation of engine oil filters  76  may allow service from above engine  12 . 
     Industrial Applicability 
     The disclosed cooling system arrangement may be used in any internal combustion engine where component life and system packaging are an issue. The disclosed cooling system finds particular applicability with inline combustion engines, where a space between opposing banks of cylinders is unavailable for packaging use. As described above, components of the disclosed cooling system may be mounted to the inline combustion engine in locations at the sides of the engine that enhance performance and longevity of the system, while simultaneously reducing system size and customer cost. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed engine and cooling system without departing from the scope of the disclosure. Other embodiments of the disclosed engine and cooling system will be apparent to those skilled in the art from consideration of the specification and practice of the engine disclosed herein. For example, although relative placement of cooling system components has been described with respect to a front end and a back end of engine  12 , it is contemplated that the front and back ends of engine  12  may be reversed, if desired. Further, the components described as being mounted at a side of engine  12 , may be directly mounted to engine block  52  and/or cylinder head  66  or indirectly mounted via a bracket or another passage, as desired. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.