Patent Publication Number: US-2023151761-A1

Title: Fluid-Cooled Manifolds and Engine Systems

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. Pat. Application No. 17/478,269, filed Sep. 17, 2021, entitled “Fluid-Cooled Manifolds and Engine Systems,” which is a division of U.S. Pat. Application No. 16/855,990, filed Apr. 22, 2020, entitled “Fluid-Cooled Manifolds and Engine Systems,” which claims priority to U.S. Provisional Application No. 62/957,681, filed Jan. 6, 2020, entitled “Fluid-Cooled Manifolds and Engine Systems.” The entire disclosure contents of U.S. Pat. Application No. 17/478,269, U.S. Pat. Application No. 16/855,990, and U.S. Provisional Application No. 62/957,681 are herewith incorporated by reference into the present application. 
    
    
     BACKGROUND 
     As an internal combustion engine is operated, the exhaust typically leaves the engine at an elevated temperature. Rather than simply emit the exhaust into the atmosphere and allow the energy to go to waste, there are various ways in which the energy in the exhaust can be captured and utilized. For example, a turbocharger can be driven by the exhaust in order to pressurize intake air into the engine. With the pressurized intake air, additional fuel can also be added to the engine in order to produce more power. 
     As the power output of the engine increases, the exhaust temperature will typically also increase. While increases in the temperature of the exhaust represent additional energy that might be recaptured, higher temperatures may approach or exceed the operating limits of the materials of the exhaust components or of the turbocharger. Thus, the turbocharger cannot be operated where the exhaust temperature exceeds an operating threshold, which puts a limit on the overall power output of the engine. 
     Unless otherwise indicated herein, the description provided in this section is not prior art to the claims and is not admitted to be prior art by inclusion in this section. 
     SUMMARY 
     The present disclosure describes implementations that relate to a fluid-cooled manifold. Beneficially, embodiments described herein may provide the ability to increase the power output of an engine without damaging exhaust components of the engine or a turbocharger associated with the engine. 
     In a first aspect, the present disclosure describes a fluid-cooled manifold for cooling exhaust from an engine. The fluid-cooled manifold includes a plurality of exhaust runners including a first exhaust runner and a second exhaust runner, where the first exhaust runner is detached from the second exhaust runner. Each of the plurality of exhaust runners includes a runner body having an inlet end and an outlet end, an exhaust conduit extending through the runner body from an exhaust inlet opening at the inlet end of the runner body to an exhaust outlet opening at the outlet end of the runner body, and a coolant passage extending through the runner body from a coolant inlet opening to a coolant outlet opening. The fluid-cooled manifold also includes an exhaust collection manifold including a plurality of inlets. Each inlet of the exhaust collection manifold is coupled to the exhaust outlet opening of a respective one of the plurality of exhaust runners. Further, the fluid-cooled manifold also includes a coolant feed pipe and a coolant exit pipe. The coolant feed pipe includes a plurality of outlets, where each outlet of the coolant feed pipe is coupled to the coolant inlet of a respective one of the plurality of exhaust runners. The coolant exit pipe includes a plurality of inlets, where each inlet of the coolant exit pipe is coupled to the coolant outlet of a respective one of the plurality of exhaust runners. 
     In an embodiment of the fluid-cooled manifold, for each exhaust runner of the plurality of exhaust runners, the coolant passage is concentrically disposed around the exhaust conduit. 
     In another embodiment of the fluid-cooled manifold, for each exhaust runner of the plurality of exhaust runners, the coolant passage has an annular cross section that surrounds the exhaust conduit and that extends along a majority of a length the exhaust conduit. 
     In another embodiment of the fluid-cooled manifold, for each exhaust runner of the plurality of exhaust runners, the coolant inlet opening is disposed at the inlet end of the exhaust runner and the coolant outlet opening is disposed at the outlet end of the exhaust runner. 
     In another embodiment of the fluid-cooled manifold, for each exhaust runner of the plurality of exhaust runners, the coolant inlet opening is disposed at the outlet end of the exhaust runner and the coolant outlet opening is disposed at the inlet end of the exhaust runner. 
     In another embodiment of the fluid-cooled manifold, the plurality of exhaust runners includes a third exhaust runner and a fourth exhaust runner. 
     In another embodiment of the fluid-cooled manifold, each exhaust runner of the plurality of exhaust runners is detached from the other exhaust runners of the plurality of exhaust runners. 
     In another embodiment of the fluid-cooled manifold, each exhaust runner of the plurality of exhaust runners has the same shape as the other exhaust runners of the plurality of exhaust runners. 
     In another embodiment of the fluid-cooled manifold, the coolant feed pipe and the coolant exit pipe have the same shape. 
     In another aspect, the disclosure describes an engine system. The engine system includes a plurality of exhaust ports including a first group of exhaust ports. The engine system also includes a first fluid-cooled manifold coupled to the engine configured to receive exhaust from the first group of exhaust ports. The first fluid-cooled manifold includes a first group of exhaust runners including a first exhaust runner and a second exhaust runner. The first exhaust runner is detached from the second exhaust runner. Each of the first group of exhaust runners includes a runner body having an inlet end and an outlet end, an exhaust conduit extending through the runner body from an exhaust inlet opening at the inlet end of the runner body to an exhaust outlet opening at the outlet end of the runner body, wherein the exhaust inlet is coupled to a respective exhaust port of the first group of exhaust ports, and a coolant passage extending through the runner body from a coolant inlet opening to a coolant outlet opening. The first fluid-cooled manifold also includes an exhaust collection manifold including a plurality of inlets. Each inlet of the exhaust collection manifold is coupled to the exhaust outlet opening of a respective one of the first group of exhaust runners. The first fluid-cooled manifold also includes a coolant feed pipe including a plurality of outlets and a coolant exit pipe including a plurality of inlets. Each outlet of the coolant feed pipe is coupled to the coolant inlet of a respective one of the first group of exhaust runners. Each inlet of the coolant exit pipe is coupled to the coolant outlet of a respective one of the first group of exhaust runners. 
     In an embodiment of the engine system, for each exhaust runner of the first group of exhaust runners of the first fluid-cooled manifold, the coolant passage is concentrically disposed around the exhaust passage. 
     In another embodiment of the engine system, for each exhaust runner of the first group of exhaust runners of the first fluid-cooled manifold, the coolant passage has an annular cross section that surrounds the exhaust passage and that extends along a majority of the exhaust passage. 
     In another embodiment of the engine system, the engine system further includes a turbocharger, where the first fluid-cooled manifold is coupled to the turbocharger and is configured to deliver cooled exhaust to the turbocharger. 
     In another embodiment of the engine system, the plurality of exhaust ports of the engine further includes a second group of exhaust ports and the engine system further includes a second fluid-cooled manifold. The second fluid-cooled manifold includes a second group of exhaust runners. Each exhaust runner of the second group of exhaust runners including an exhaust inlet coupled to a respective exhaust port of the second group of exhaust ports. 
     In another embodiment of the engine system, each of the exhaust runners of the first group of exhaust runners and the second group of exhaust runners has the same shape. 
     In another aspect, the disclosure describes a coolant circulation system for an engine. The coolant circulation system includes a pump configured to circulate coolant through the coolant circulation system. A first cooling line is in fluid communication with the pump, where the first cooling line includes engine coolant passages extending through a portion of the engine. A first junction is downstream of the first cooling line. A first cold return line extends from the first junction to the pump. A first hot return line extends from the first junction to the pump, where the first hot return line passes through a heat exchanger configured to cool the coolant in the first hot return line. A first thermostat is disposed at the first junction and configured to direct a portion of flow from the first cooling line to the first cold return line or the first hot return line based on a temperature of the coolant at the first junction. A second cooling line is in fluid communication with the pump, where the second cooling line includes manifold coolant passages extending through a first cooled exhaust manifold. A second junction is downstream of the second cooling line. A second cold return line extends from the second junction to the pump. A second hot return line extends from the second junction to the pump, where the second hot return line passes through the heat exchanger so as to cool the coolant in the second hot return line. A second thermostat is disposed at the second junction and is configured to direct a portion of flow from the second cooling line to the second cold return line or the second hot return line based on a temperature of the coolant at the second junction. 
     In an embodiment of the coolant circulation system, each manifold coolant passage of the first cooled exhaust manifold is an annular passage concentrically disposed around a respective exhaust passage of the first cooled exhaust manifold. 
     In another embodiment of the coolant circulation system, the second cooling line also includes engine coolant passages extending through a portion of the engine. 
     In another embodiment of the coolant circulation system, the first cooling line includes coolant passages extending through an engine head of the engine. 
     In another embodiment of the coolant circulation system, the manifold coolant passages extending through the first cooled exhaust manifold are part of a first portion of the second cooling line. A second portion of the second cooling line includes manifold coolant passages extending through a second cooled exhaust manifold, and the first portion of the second cooling line runs parallel to the second portion of the second cooling line. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure, and together with the detailed description serve to explain the principles of the disclosure. No attempt is made to show structural details of embodiments of the disclosure in more detail than may be necessary for a fundamental understanding of the embodiments of the disclosure and various ways in which it may be practiced. 
         FIG.  1    is a perspective view of a fluid-cooled manifold according to an embodiment of the disclosure; 
         FIG.  2    is an exploded view of the fluid-cooled manifold according to  FIG.  1   ; 
         FIG.  3    is a cross-sectional view of an exhaust runner of the fluid-cooled manifold according to  FIG.  1   ; 
         FIG.  4    is a schematic depiction of the fluid-cooled manifold according to  FIG.  1   ; 
         FIG.  5    is a schematic depiction of a fluid-cooled manifold according to another embodiment of the disclosure; 
         FIG.  6    is a is a schematic depiction of a fluid-cooled manifold according to another embodiment of the disclosure; 
         FIG.  7    is a schematic depiction of a fluid-cooled manifold according to another embodiment of the disclosure; 
         FIG.  8    is a perspective view of an engine system according to an embodiment of the disclosure; 
         FIG.  9    is a schematic depiction of the engine system according to  FIG.  8   ; and 
         FIG.  10    is a schematic depiction of a coolant circulation system according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary apparatus and systems are described herein. It should be understood that the word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or feature described herein as “exemplary” or an “example” is not necessarily to be construed as preferred or advantageous over other embodiments or features. The exemplary embodiments described herein are not meant to be limiting. It will be readily understood that certain aspects of the disclosed apparatus and systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein. 
       FIG.  1    illustrates a fluid-cooled manifold  100  in accordance with example embodiment of the disclosure that is configured to receive and cool exhaust from an engine. An exploded view of the fluid-cooled manifold  100  is shown in  FIG.  2   . The fluid-cooled manifold  100  may include a plurality of exhaust runners  102 A- 102 D, including a first exhaust runner  102 A, a second exhaust runner  102 B, a third exhaust runner  102 C, and a fourth exhaust runner  102 D. The exhaust runners  102 A- 102 D may be disposed in a line, as shown in  FIG.  1   , where the first exhaust runner  102 A and the second exhaust runner  102 B are positioned toward the center of the fluid-cooled manifold  100 , whereas the third exhaust runner  102 C and the fourth exhaust runner  102 D are positioned on the periphery of the fluid-cooled manifold. As discussed in more detail below, the first exhaust runner  102 A and the second exhaust runner  102 B may be detached from one another. 
     Each of the exhaust runners  102 A- 102 D may be configured to attach to an engine in order to receive exhaust from the engine, as described in more detail below. For example, each exhaust runner  102 A- 102 D is configured to attach an exhaust port associated with a cylinder of the engine. In some embodiments the fluid-cooled manifold is configured such that each exhaust runner  102 A- 102 D is paired with one cylinder of the engine. In other embodiments, each of the exhaust runners may be associated with more than one cylinder of the engine. On the other hand, in other embodiments, more than one exhaust runner may be associated with a cylinder of the engine. For example, in some embodiments, two exhaust runners may be associated with each cylinder of the engine. In such embodiments, an adapter may be positioned between the fluid-cooled manifold and the exhaust ports of the engine in order to combine or divide exhaust from the exhaust ports for introduction into the fluid-cooled manifold. 
     The fluid-cooled manifold  100  may also include an exhaust collection manifold  140  that receives exhaust from the exhaust runners  102 A- 102 D and directs the exhaust downstream, as explained in more detail below. The exhaust collection manifold  140  may include a plurality of inlets  142 A- 142 D, as shown in  FIG.  2   , that are respectively coupled to the exhaust runners  102 A- 102 D. Further, the fluid-cooled manifold  100  may also include a coolant feed pipe  150   and a coolant exit pipe  154 . The coolant feed pipe  150  may include a plurality of outlets  152 A- 152 D, as shown in  FIG.  2   , that are respectively coupled to the exhaust runners  102 A- 102 D. Likewise, the coolant exit pipe  154  may include a plurality of inlets  156 A- 156 D, also shown in  FIG.  2   , that are respectively coupled to the exhaust runners  102 A- 102 D. The coolant feed pipe  150  and coolant exit pipe  154  may be part of a coolant circulation system that is configured to circulate a coolant through the fluid-cooled manifold, as explained in more detail below. Accordingly, the coolant feed pipe  150  may include an inlet  158 A for receiving coolant that is circulated through the coolant circulation system. Further, the coolant feed pipe  150  may be configured to deliver the coolant to the exhaust runners  102 A- 102 D through the feed pipe outlets  152 A- 152 D. Likewise, the coolant exit pipe  154  may be configured to receive the coolant from the exhaust runners  102 A- 102 D via the exit pipe inlets  156 A- 156 D and include an outlet  158 B to continue circulation of the coolant through the coolant circulation system. 
     A side cross-sectional view of one of the exhaust runners  102  (e.g., exhaust runner  102 A) of fluid-cooled manifold  100  is shown in  FIG.  3   . As explained in more detail below, the exhaust runners may all have a similar configuration. As shown in  FIG.  3   , exhaust runner  102  may include a runner body  104  having an inlet end  110  and an outlet end  120 . The inlet end  110  may include a first attachment surface  112  configured to be secured against the engine so as to surround an exhaust port of the engine. Further, the inlet end  110  may also include an exhaust inlet opening  114  that provides fluid access to an exhaust conduit  106  that extends through the runner body  104 . The exhaust inlet opening  114  extends through the first attachment surface  112 . The outlet end  120  may include a second attachment surface  122  that is attached to a respective inlet  142 A- 142 D of the inlets of the exhaust collection manifold  140 . In various embodiments, a seal, such as a gasket, may be included between the second attachment surface  122  and the respective inlet  142 A- 142 D of the exhaust collection manifold  140 . The outlet end  120  of each exhaust runner may also include an exhaust outlet opening  124  that extends through the second attachment surface  122  and provides fluid access to the exhaust conduit  106 . Thus, the exhaust conduit  106  may run through the runner body  104  from the exhaust inlet opening  114  at the inlet end  110  to the exhaust outlet opening  124  at the outlet end  120 . 
     The exhaust runner  102  may also include a coolant passage  108  that extends through the runner body  104  from a coolant inlet opening  116  to a coolant outlet opening  126 . To receive coolant from the coolant feed pipe  150 , the coolant inlet opening  116  may be coupled to a respective one of the feed pipe outlets  152 A- 152 D (as shown in  FIG.  2   ). After passing through the exhaust runner  102  the coolant may exit the coolant passage  108  via the coolant outlet opening  126  and flow into the coolant exit pipe  154  via a respective one of the exit pipe inlets  156 A- 156 D (as shown in  FIG.  2   ). 
     With further reference to  FIG.  3   , in some embodiments, the coolant passage  108  of each of the exhaust runners  102  may be concentrically disposed around the exhaust conduit  106 . For example, the exhaust conduit  106  of each exhaust runner  102  may extend from the inlet end  110  to the outlet end  120  along a path through the runner body  104 , and the coolant passage  108  may concentrically surround the exhaust conduit  106  along the path from the inlet end  110  to the outlet end  120 . Moreover, the exhaust conduit  106  may be defined within an interior wall  130  that is formed by a portion of the runner body  104 . The interior wall  130  may then be surrounded by an exterior wall  132  of the runner body  104 , thereby defining the coolant passage  108  between the interior wall  130  and the exterior wall  132 . Accordingly, the coolant passage  108  is positioned concentrically around the exhaust conduit  106 . Having the coolant passage  108  be concentrically disposed around the exhaust conduit  106  allows a large area of heat transfer between the exhaust conduit  106  and the coolant passage  108 . Accordingly, such a configuration may provide more heat transfer from the exhaust within the exhaust conduit  106  to the coolant in the coolant passage  108  than a coolant passage without a concentric configuration operating under similar conditions. 
     In some embodiments, the coolant passage  108  of each exhaust runner  102  has an annular cross section that surrounds the exhaust conduit  106  and extends along a majority of a length of the exhaust conduit  106 . In other words, in some embodiments, the coolant passage  108  completely surrounds the exhaust conduit  106  without any connection between interior wall  130  and the exterior wall  132  of the runner body. Moreover, in some embodiments, the annular cross section of the coolant passage  108  extends over substantially the entire exhaust conduit  106 , except at the ends of the exhaust runner  102  around the exhaust inlet opening  114  and the exhaust outlet opening  124 . In other embodiments, partitions may extend between the interior wall  130  and the exterior wall  132  such that the coolant passage  108  is not completely annular along a majority of the exhaust conduit  106 . Such partitions may provide added stability or control the flow direction of any coolant running through the coolant passage  108 . 
     In some embodiments, the coolant inlet opening  116  of the coolant passage  108  of each exhaust runner  102  may be disposed at the inlet end  110  of the exhaust runner  102  and the coolant outlet opening  126  may be disposed at the outlet end  120  of the exhaust runner  102 . In such a configuration, the exhaust and the coolant will run in parallel through the exhaust runner  102 . In other embodiments, the coolant inlet opening  116  of the coolant passage  108  of each exhaust runner  102  may be disposed at the outlet end  120  of the exhaust runner  102  and the coolant outlet opening  126  may be disposed at the inlet end  110  of the exhaust runner, such that the exhaust and coolant run in counter flow. Providing the coolant inlet opening  116  and the coolant outlet opening  126  at the ends of the exhaust runner  102  allows for a greater area of thermal contact between the exhaust conduit  106  and the coolant passage  108 . Still, in other embodiments, due to geometric or other constraints, the coolant inlet opening  116  and/or the coolant outlet opening  126  may be disposed at another location, such as toward the center of the exhaust runner  102 . 
     In some embodiments, the coolant inlet opening  116  is configured such that coolant flowing through the coolant inlet opening  116  flows perpendicular to the interior wall  130  that defines the exhaust conduit  106  so as to impinge upon the interior wall  130 . Further, in some embodiments the coolant passage  108  is configured so as to form a swirling flow of coolant within the coolant passage  108 , such that the coolant swirls around the exhaust conduit  106 . These and other configurations of the flow pattern of coolant within the coolant passage  108  can assist in promoting heat transfer between the exhaust and the coolant. 
     In some embodiments, the fluid-cooled manifold includes four exhaust runners. For example, the fluid-cooled manifold  100  shown in  FIG.  1    has four exhaust runners  102 A- 102 D arranged in a row. The first exhaust runner  102 A and second exhaust runner  102 B are positioned toward the center of the row of exhaust runners  102 A- 102 D, while the third exhaust runner  102 C and fourth exhaust runner  102 D are positioned at the ends of the row of exhaust runners  102 A- 102 D. A schematic depiction of fluid-cooled manifold  100  is also shown in  FIG.  4    for comparison to schematic depictions of other fluid-cooled manifolds discussed below.  FIG.  4    illustrates the four exhaust runners  102 A- 102 D. Each of the exhaust runners  102 A- 102 D delivers exhaust from the engine to the exhaust collection manifold  140 . As the exhaust passes through the exhaust runners  102 A- 102 D it is cooled by the coolant that is circulated through the exhaust runners  102 A- 102 D. Further, the coolant is received in the exhaust runners  102 A- 102 D  from a coolant feed pipe  150  that is coupled to each of the exhaust runners  102 A- 102 D. Likewise, the coolant returns to the coolant circulation system via the coolant exit pipe  154 , which is also coupled to each of the exhaust runners  102 A- 102 D. 
     In other embodiments, the fluid-cooled manifold includes a different number of exhaust runners. Accordingly, such embodiments may be configured to operate with engines having a different number of exhaust ports. For example,  FIG.  5    shows a schematic depiction of a fluid-cooled manifold  500  that includes only two exhaust runners, including first exhaust runner  502 A and second exhaust runner  502 B. Both the first exhaust runner  502 A and the second exhaust runner  502 B deliver exhaust from the engine to the exhaust collection manifold  540 . Again, as the exhaust passes through the exhaust runners  502 A- 502 B it is cooled by the coolant that is circulated through the exhaust runners  502 A- 502 B. A coolant feed pipe  550  is coupled to both the first exhaust runner  502 A and the second exhaust runner  502 B in order to deliver coolant to both exhaust runners  502 A- 502 B. Likewise, the coolant returns to the coolant circulation system via the coolant exit pipe  554 , which is also coupled to both of the exhaust runners  502 A- 502 B. 
     As another example,  FIG.  6    shows a schematic depiction of a fluid-cooled manifold  600  that includes six exhaust runners. Similar to fluid-cooled manifold  100 , fluid-cooled manifold  600  includes a first exhaust runner  602 A and a second exhaust runner  602 B that are located at the center of a row of exhaust runners  602 A- 602 F. Further, a third exhaust runner  602 C and a fourth exhaust runner  602 D are disposed at the end of the row of exhaust runners  602 A- 602 F. In addition, a fifth exhaust runner  602 E and a sixth exhaust runner  602 F are located at intermediate positions between the center and the ends of the row. Each of the exhaust runners  602 A- 602 D delivers exhaust from the engine to the exhaust collection manifold  640 . As the exhaust passes through the exhaust runners  602 A- 602 D it is cooled by coolant being circulated through the exhaust runners  602 A- 602 F. Further, the coolant is received in the exhaust runners  602 A- 602 F from a coolant feed pipe  650  that is coupled to each of the exhaust runners  602 A- 602 F. Likewise, the coolant returns to the coolant circulation system via the coolant exit pipe  654 , which is coupled to each of the exhaust runners  602 A- 602 F. 
     In some embodiments, the first exhaust runner is detached from the second exhaust runner. For example, in each of the embodiments of the fluid-cooled manifold  100 ,  500 ,  600  shown in  FIGS.  1 - 6   , the first exhaust runner  102 A,  502 A,  602 A is detached from the respective second exhaust runner  102 B,  502 B,  602 B. The term “detached,” as used herein, refers to a situation where two components are neither directly coupled to one another, nor part of a larger construction formed as a single integral piece. Thus, the detached first and second exhaust runners, e.g.,  102 A,  102 B, are neither directly coupled to one another, nor are they part of a larger construction that includes the exhaust runners, e.g.,  102 A,  102 B, in a single integral piece. Further, in some embodiments, the detached exhaust runners are separated from one another by a space. In other embodiments, the detached exhaust runners may abut one another while not being directly coupled to one another. 
     In some embodiments, each of the exhaust runners  102 A- 102 D is detached from all of the other exhaust runners  102 A- 102 D of the fluid-cooled manifold  100 . For example, in fluid-cooled manifold  100 , exhaust runners  102 A- 102 D are arranged in a row, but none of the exhaust runners  102 A- 102 D are attached to one another. In contrast, each exhaust runner  102 A- 102 D is detached from the others. Instead, the exhaust runners  102 A- 102 D are connected to one another via their attachment to the exhaust collection manifold  140 , coolant feed pipe  150  and coolant exit pipe  154 . 
     The use of exhaust runners  102 A- 102 D that are detached from one another allows the portion of the fluid-cooled manifold  100  that includes two different fluid paths, i.e., the exhaust runners  102 A- 102 D that include both the exhaust conduit  106  and the coolant passage  108 , to be manufactured as a group of smaller individual components. Including separate passages that accommodate different fluids within the body of a manifold is complicated. Further, providing a single large manifold with various passages for different exhaust streams as well as additional passages for coolant channels that cool the exhaust streams would add considerable complexity. By designing the manifold as several different components, including individual and detached exhaust runners that each include a single exhaust conduit  106 , the manufacturing can be simplified. 
     In other embodiments, at least some of the exhaust runners are attached to one another. For example,  FIG.  7    depicts an embodiment of a fluid-cooled manifold  700  that includes four exhaust runners  702 A- 702 D arranged in a row, similar to the fluid-cooled manifold  100  shown in  FIG.  1   . The first exhaust runner  702 A and second exhaust runner  702 B are positioned toward the center of the row, while the third exhaust runner  702 C and fourth exhaust runner  702 D are positioned at the ends of the row. As with the previously described embodiments, each of the exhaust runners  702 A- 702 D delivers exhaust from the engine to the exhaust collection manifold  740 , receives coolant from a coolant feed pipe  750  and returns the coolant to a coolant exit pipe  754 . Similar to the other embodiments, the first exhaust runner  702 A is detached from the second exhaust runner  702 B. However, the first exhaust runner  702 A is attached to third exhaust runner  702 C, as identified in regions  703 A. In particular, the first exhaust runner  702 A is attached to third exhaust runner  702 C at the inlet end and at the outlet end. For example, the first exhaust runner  702 A may be formed in a single integral piece with the third exhaust runner  702 C. The second exhaust runner  702 B may also be attached to the fourth exhaust runner  702 D, as identified in regions  703 B. For example, the second exhaust runner  702 B may be formed in a single integral piece with the fourth exhaust runner  702 D, as shown in  FIG.  7   . In some embodiments, the exhaust runners are attached to one another in pairs, allowing a fluid-cooled manifold to be constructed with any even number of exhaust runners. 
     In contrast to the embodiment of  FIG.  1   , where all of the exhaust runners  102 A- 102 D are detached from one another, and the embodiment of  FIG.  7   , where some of the exhaust runners  702 A- 702 D are attached to one another, in other embodiments, all of the exhaust runners are attached to one another. For example, in some embodiments, all of the exhaust runners of the fluid-cooled manifold are formed in a single integral piece. 
     In some embodiments, the exhaust runners  102 A- 102 D have a similar configuration. For example, in some embodiments, the height and width of each of the exhaust runners  102 A- 102 D may be the same. Likewise, in some embodiments, the length of the exhaust conduit  106  and/or the length of the coolant passage  108  of each of the exhaust runners  102 A- 102 D may be the same. Further, in some embodiments, each of the exhaust runners  102 A- 102 D may have the same shape. For example, each of exhaust runners  102 A- 102 D in fluid-cooled manifold  100 , shown in  FIGS.  1  and  2    have the same shape. Two components that have the “same shape,” as the phrase is used herein, refers to components that are manufactured using the same method or tools, such that the components are interchangeable. For example, two components having the same shape may be molded or cast in the same die. Differences between components having the same shape may be based on manufacturing tolerances or variations caused by installation. 
     The use of exhaust runners  102 A- 102 D that have the same shape simplifies manufacturing, as a smaller, less complicated component can be reproduced several times to form a substantial portion of the fluid-cooled manifold  100 . Moreover, in fluid-cooled manifolds where each of the exhaust runners has the same shape, the fluid-cooled manifold can be redesigned by adding or removing one or more exhaust runner. Accordingly, accommodating engines with different numbers of cylinders can be achieved without redesigning the entire manifold. 
     Although there are advantages in having each exhaust runner have the same shape, in some embodiments, the exhaust runners  102 A- 102 D may have different configurations and different shapes. For example, in some embodiments, the exhaust runners  102 A- 102 D may bend at different angles, or have bends with different radiuses of curvature. Other aspects of the shape and configuration of the exhaust runners  102 A- 102 D may also differ. Differences in the geometries of the exhaust runners may be beneficial to meet space constraints or for other reasons. 
     In some embodiments, each exhaust runner  102  has a symmetrical configuration and is substantially symmetrical about a central plane of the exhaust runner. For example, the exhaust conduit  106  may follow the central plane of the exhaust runner  102  and be surrounded by the coolant passage  108  on both sides of the central plane. Further, in some embodiments, both the coolant inlet opening  116  and the coolant outlet opening  126  may be positioned on the central plane of the exhaust runner  102 . By providing the exhaust runners  102 A- 102 D with a symmetrical configuration, the exhaust runners  102 A- 102 D may operate independently of the overall orientation and position of the fluid-cooled manifold with respect to the engine. Thus, the exhaust runners  102 A- 102 D can be implemented in a fluid-cooled manifold  100  configured to couple to the right side of an engine, or the same exhaust runners  102 A- 102 D can be implemented in a fluid-cooled manifold  100  configured to couple to the left side of an engine. 
     In some embodiments, the central plane of each of the exhaust runners  102 A- 102 D may be parallel within the fluid-cooled manifold  100 . By providing the exhaust runners  102 A- 102 D with a parallel alignment throughout the fluid-cooled manifold  100 , the size of the fluid-cooled manifold  100  can be modified to cooperate with engines having more or fewer cylinders simply by adding or removing exhaust runners. The relative position or angle of one exhaust runner does not need to be modified with respect to neighboring exhaust runners as the number of exhaust runners changes, since the respective orientation is always parallel. 
     In some embodiments, the coolant feed pipe  150  and the coolant exit pipe  154  may have the same shape. Such a configuration simplifies manufacture of the fluid-cooled manifold  100 , since both the coolant feed pipe  150  and the coolant exit pipe  154  can be formed by the same part, similar to the various exhaust runners  102 A- 102 D. 
     The above-described components of the fluid-cooled manifold  100  may be composed of a variety of different materials. For example, the components may be formed of metal, such as steel or aluminum. Likewise the above-described components may be formed of a plastic material. Further, in some embodiments, different components are formed of different materials. For example, in some embodiments, the exhaust runners  102 A- 102 D may be formed of steel, while the coolant feed pipe  150  and the coolant exit pipe  154  are formed of plastic. The fluid-cooled manifold  100  may include additional components to those that have been described, such as fasteners, seals, sensors or any other components that may be advantageous. 
     The fluid-cooled manifold  100  may be manufactured using a variety of different methods. For example, the exhaust runners  102  may be molded or cast. Likewise, the exhaust collection manifold  140 , coolant feed pipe  150 , and coolant exit pipe  154  may also be molded or cast. Further, each of these components can be machined from a block of material, or manufactured by an additive manufacturing process. Other methods of manufacture are also possible. 
     In another aspect, the disclosure provides an engine system.  FIG.  8    illustrates an engine system  860  according to an embodiment of the disclosure. The engine system  860  may include an engine  862 , at least one fluid-cooled manifold  800 , a turbocharger  866 , and a radiator  868 . A schematic depiction of the engine system  860  is shown in  FIG.  9    to illustrate various features of the depicted embodiment. Engine system  860 , as shown in  FIG.  9   , includes an engine  862  that may include a plurality of exhaust ports  864 A- 864 H, including a first group of exhaust ports  864 A- 864 D. A first fluid-cooled manifold  800  may be coupled to the engine  862  and configured to receive exhaust from the first group of exhaust ports  864 A- 864 D. The first fluid-cooled manifold  800  may be configured according to any of the above-described embodiments. For example, the first fluid-cooled manifold  800  may include a first group of exhaust runners  802 A- 802 D that are detached from one another. Each of the first group of exhaust runners  802 A- 802 D of the first fluid-cooled manifold  800  may be coupled to a respective one of the first group of exhaust ports  864 A- 864 D of the engine  862 . 
     The first fluid-cooled manifold  800  may also include an exhaust collection manifold  840  including a plurality of inlets  842 A- 842 D, where each inlet  842 A- 842 D of the exhaust collection manifold  840  is coupled to an exhaust outlet opening of a respective one of the first group of exhaust runners  802 A- 802 D. The first fluid-cooled manifold  800  may also include a coolant feed pipe  850  and a coolant exit pipe  854 . As described above with respect to various embodiments of the fluid-cooled manifold, the coolant feed pipe  850  may be configured to supply coolant to the first group of exhaust runners  802 A- 802 D and the coolant exit pipe  854  may be configured to receive coolant from the first group of exhaust runners  802 A- 802 D. 
     In some embodiments of the engine system  860 , the engine  862  includes a second group of exhaust ports  864 E- 864 H. A second fluid-cooled manifold  801  may be coupled to the engine  862  and configured to receive exhaust from the second group of exhaust ports  864 E- 864 H. The second fluid-cooled manifold  801  may be configured according to any of the above-described embodiments. For example, each of the second group of exhaust runners  802 E- 802 H of the second fluid-cooled manifold  801  may be coupled to a respective one of the second group of exhaust ports  864 E- 864 H of the engine  862 . Further, the second fluid-cooled manifold  801  may also include an exhaust collection manifold  841  including a plurality of inlets  843 A- 843 D, where each inlet  843 A- 843 D of the exhaust collection manifold  841  is coupled to an exhaust outlet opening of a respective one of the second group of exhaust runners  802 E- 802 H. The second fluid-cooled manifold  800  may also include a coolant feed pipe  851  and a coolant exit pipe  855 . As described above with respect to various embodiments of the fluid-cooled manifold, the coolant feed pipe  851  may be configured to supply coolant to the second group of exhaust runners  802 E- 802 H and the coolant exit pipe  855  may be configured to receive coolant from the first group of exhaust runners  802 E- 802 H. A second fluid-cooled manifold  801  may be particularly useful where the exhaust ports  864 A- 864 H of the engine  862  are disposed in two groups, for example in a V8 engine, where the exhaust ports  864 A- 864 H are disposed on either side of the engine  862 . 
     In some embodiments of the engine system, each of the exhaust runners  802 A- 802 H of both the first group and the second group has the same configuration. Accordingly, the first fluid-cooled manifold  800  and the second fluid-cooled manifold  801  may be formed from eight exhaust runners  802  that are all manufactured as the same part. Likewise, in some embodiments the exhaust collection manifold  840  of the first fluid-cooled manifold  800  and the exhaust collection manifold  841  of the second fluid-cooled manifold  801  may be have the same shape and be manufactured as the same part. Further, in some embodiments, the coolant feed pipe  850  of the first fluid-cooled manifold  800  and the coolant feed pipe  851  of the second fluid-cooled manifold  801  may have the same shape and be manufactured as the same part. Similarly, in some embodiments, the coolant exit pipe  854  of the first fluid-cooled manifold  800  and the coolant feed pipe  851  of the second fluid-cooled manifold  801  may also have the same shape and be manufactured as the same part. Indeed, in some embodiments, each of the coolant feed pipe  850  of the first fluid-cooled manifold  800 , the coolant feed pipe  851  of the second fluid-cooled manifold  801 , the coolant exit pipe  854  of the first fluid-cooled manifold  800 , and the coolant feed pipe  851  of the second fluid-cooled manifold  801 , may have all the same shape and be manufactured as the same part. The similarity of the shape of these components and the ability to use the same part in both manifolds and/or as more than one component of both manifolds simplifies manufacturing, as the overall list of components is reduced and the complexity of each part is also reduced. Rather than a system having more unique components, or larger more complex components, the system can be fabricated from the reuse of several smaller, simpler components. 
     In some embodiments, the engine system  860  may include a turbocharger  866 , where the first fluid-cooled manifold  800  is coupled to the turbocharger  866  and is configured to deliver cooled exhaust to the turbocharger  866 . By cooling the exhaust prior to delivering the exhaust to the turbocharger  866 , the engine  862  may be run at higher power loads. In contrast, if the exhaust is delivered directly to the turbocharger  866  when the engine  862  is operating at high loads, the exhaust temperature may be high enough to damage components of the turbocharger  866 . For example, in some instances, when an engine  862  is operated with a turbocharger  866  at high loads, the exhaust temperature may be higher than 700° C. Many materials commonly used in turbochargers cannot withstand such high temperatures and will begin to crack or melt. Reducing the temperature of the exhaust allows the engine to continue running at high loads without damaging the engine or turbocharger. 
     In some embodiments, the fluid-cooled manifolds  800 ,  801  may reduce the temperature of the exhaust by more than 100° C. Such a decrease in temperature can allow the engine to be run at high power output without damaging the turbocharger. As an example, an 8.8 L V8 engine operated while using a turbocharger and a pair of the fluid-cooled manifolds of the disclosure can be operated at over 200 kW without damaging the turbocharger. 
     In some embodiments, the engine system  860  may include a radiator  868 . The radiator  868  can be used to reduce the temperature of the coolant coming from the exhaust runners  802 A- 802 H and allow lower temperature coolant to be recirculated back to the exhaust runners  802 A- 802 H. The lower temperature of the coolant allows the coolant to remove a greater amount of energy from the exhaust within the fluid-cooled manifolds  800 ,  801 . 
     In another aspect, the disclosure provides a coolant circulation system for an engine.  FIG.  10    illustrates a schematic depiction of a coolant circulation system  1070  according to an embodiment of the disclosure. The coolant circulation system  1070  may include a pump  1072  configured to circulate coolant through the coolant circulation system  1070 . The coolant circulation system  1070  may also include a first cooling line  1074  that is in fluid communication with the pump  1072 . The first cooling line  1074  may include engine coolant passages  1076  extending through a portion of an engine  1062 , such as the engine block  1078  and the engine head  1080 . The first cooling line  1074  may lead to a first junction  1082  where a first thermostat  1084  is disposed. The first thermostat  1084  may be configured to direct a portion of flow from the first cooling line  1074  to a first cold return line  1086  or a first hot return line  1088 . The first cold return line  1086  may extend from the first junction  1082  back to the pump  1072 . On the other hand, the first hot return line  1088  may extend from the first junction  1082  through a heat exchanger  1068 , such as a radiator, that is configured to cool the coolant in the first hot return line  1088 . 
     The first thermostat  1084  allows the coolant to continue circulating through the engine coolant passages  1076  and returning to the pump  1072  without passing through the heat exchanger  1068  until the coolant reaches a predetermined temperature. Once the coolant temperature is at or above the predetermined temperature at the first thermostat  1084 , the first thermostat  1084  will route at least a portion of the coolant through the heat exchanger  1068  before it is returned to the pump  1072  and engine  1062 . 
     The coolant circulation system  1070  may also include a second cooling line  1090  that is in fluid communication with the pump  1072  and includes manifold coolant passages  1008  extending through a first cooled exhaust manifold  1000 . The second cooling line  1090  may lead to a second junction  1092  where a second thermostat  1094  is disposed. The second thermostat  1094  may be configured to direct a portion of flow from the second cooling line  1090  to a second cold return line  1096  or a second hot return line  1098 . The second cold return line  1086  may extend from the second junction  1092  back to the pump  1072 . On the other hand, the second hot return line  1098  may extend from the second junction  1092  through the heat exchanger  1068  that is configured to cool the coolant in the second hot return line  1098 . 
     Similar to the first thermostat  1084 , the second thermostat  1094  allows the coolant to continue circulating through the manifold coolant passages  1008  and returning to the pump  1072  without passing through the heat exchanger  1068  until the coolant reaches a predetermined temperature. Once the coolant temperature is at or above the predetermined temperature at the second thermostat  1094 , the second thermostat  1094  will route at least a portion of the coolant through the heat exchanger  1068  before it is returned to the pump  1072  and the manifold coolant passages  1008 . 
     The coolant can be any of a number of heat transfer fluids configured to circulate through the coolant circulation system and cool the exhaust. In embodiments, the coolant may be a liquid, a gas, or a two-phase flow. In some embodiments the coolant includes water. Further, in some embodiments, the coolant may include additives, such as anti-corrosion additives and anti-freeze additives. 
     In some embodiments of the coolant circulation system  1070 , the second cooling line  1090  may include engine coolant passages  1076  in addition to the manifold coolant passages  1008 . For example, the second cooling line  1090  may include passages through the engine block  1078  before the second cooling line  1090  branches off to the manifold coolant passages  1008  through the fluid-cooled manifold  1000 . 
     In some embodiments of the coolant circulation system  1070 , the first cooling line  1074  may have a first portion that includes the manifold coolant passages  1008  extending through the first fluid-cooled manifold  1000 . Further, the first cooling line  1080  may also include a second portion that includes manifold coolant passages  1009  extending through the second fluid-cooled manifold  1001 . The first portion of the first cooling line  1080  may run parallel to the second portion of the first cooling line  1080 . 
     In some embodiments, the coolant circulation system  1070  may include an orifice downstream of the fluid-cooled manifold(s). The orifice may be configured to avoid diverting too much coolant from the engine and to increase coolant pressure in the fluid-cooled manifolds. Due to the higher coolant pressure, the boiling temperature of the coolant may be increased, such that phase change of the coolant is reduced and heat transfer to the coolant is enhanced. 
     Examples given above are merely illustrative and are not meant to be an exhaustive list of all possible embodiments, applications or modifications of the invention. Thus, various modifications and variations of the described apparatus and systems will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. Although the disclosure has been described in connection with specific embodiments, it should be understood that the claims should not be unduly limited to such specific embodiments. 
     The terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. It also is to be noted that, as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to “an exhaust runner” is a reference to one or more exhaust runners and equivalents thereof known to those skilled in the art. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the invention pertains. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. 
     Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least two units between any lower value and any higher value. As an example, if it is stated that the concentration of a component or value of a process variable such as, for example, size, angle size, pressure, time and the like, is, for example, from 1 to 90, specifically from 20 to 80, more specifically from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. 
     Particular apparatus, systems, and components are described, although any apparatus, systems, and components similar or equivalent to those described herein can be used in the practice of the claims.