Abstract:
The present disclosure considers an exhaust manifold and method of casting an exhaust manifold, where the exhaust manifold has both a portion of the exterior wall that is jacket cooled and a portion of the exterior wall that is not cooled. The non-cooled portion of the exterior is not accessible when the exhaust manifold is secured to the engine block. Furthermore, the non-cooled portion of the exterior wall of the exhaust manifold is designed to add stability during the casting process and allow for a simplified casting process with fewer cores.

Description:
TECHNICAL FIELD 
     This patent disclosure relates generally to an exhaust manifold and a method of casting an exhaust manifold and, more particularly, to a jacket-cooled exhaust manifold and a method of casting a jacket-cooled exhaust manifold. 
     BACKGROUND 
     International safety standards often specify maximum surface temperatures in engine environments. One component of the engine environment is the exhaust manifold, which accumulates exhaust gases from multiple engine cylinders into one exhaust pipe. In the marine environment, jacket-cooling is a method used to comply with safety standards specifying maximum surface temperatures. A coolant jacket can shield and cool hot exhaust manifolds coupled with an engine, thus maintaining a surface temperature below the specified maximum. Such jacket cooled exhaust manifolds can be constructed out of fabricated or cast metal. 
     Prior exhaust manifolds, such as the exhaust manifold disclosed in U.S. Pat. No. 3,921,398 to Kashmerick, have portions constructed out of cast aluminum and include a cooling jacket to reduce the surface temperature of the exhaust manifold. The prior casting methods used to construct such exhaust manifolds required a complex and a resource intensive manufacturing process, often requiring casting of multiple pieces followed by an assembly of cast portions. The present disclosure is directed to mitigating or eliminating one or more of the drawbacks discussed above. 
     SUMMARY 
     The present disclosure considers a new exhaust manifold design that is easier to manufacture leading to cost reductions during the manufacturing process. The new exhaust manifold design provides a novel method of transferring exhaust from engine cylinders to the exhaust pipe while meeting industry safety standards concerning the maximum exposed surface temperature for exhaust manifolds. To lower the difficulty and cost of manufacturing the exhaust manifold, the proposed exhaust manifold has both a portion of the exterior wall that is jacket cooled and a portion of the exterior wall that is not cooled. The non-cooled portion of the exterior is not exposed to the operator when the exhaust manifold is secured to the engine block. 
     The exhaust manifold can contain a plurality of exhaust gas inlets on one lateral side to match with engine cylinder outlets. A longitudinal exhaust passageway merges the exhaust gas from the inlets and leads to an exhaust outlet of the exhaust manifold. The exhaust manifold can also include a coolant passageway between the longitudinal exhaust passageway and the exterior wall. The coolant passageway can be fed by an inlet port, while outlet ports can allow the coolant to exit the exhaust manifold. 
     The disclosed exhaust manifold includes voids, or air pocket indentations, on the non-coolant cooled side of the exhaust manifold, between the exhaust gas inlets on the lateral side of the exhaust manifold facing the engine cylinders. Because the air pocket indentations are disposed between the exhaust gas inlets they are not exposed while the exhaust manifold is attached to the engine. Therefore the air pocket indentations do not have to comply with the skin surface temperature safety regulations. These air pocket indentations form the non-cooled portion of the exterior wall of the exhaust manifold. The material used to form the air pockets indentations can also provide internal support to the exhaust gas inlets during the casting process. The air pocket indentations can also reduce the number of cores required during the casting process used to manufacture the exhaust manifold. The air pocket indentations can also simplify the shape of cores used in the casting process. 
     The present disclosure also considers a method of casting an exhaust manifold that provides a low cost and efficient method of transferring exhaust from engine cylinders to the exhaust pipe while meeting industry safety standards concerning the maximum exposed surface temperature for exhaust manifolds. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the first lateral side of an example exhaust manifold. 
         FIG. 2  is a perspective view of the second lateral side of an example exhaust manifold. 
         FIG. 3  is a cross-sectional view from the perspective of the bottom side of an example exhaust manifold. 
         FIG. 4  is a front side view of view of the first lateral side of an example exhaust manifold 
         FIG. 5  is a cross-sectional view from the perspective of the second lateral side of an example exhaust manifold. 
         FIG. 6  is a cross-sectional view from the perspective of the first distal end of an example exhaust manifold. 
         FIG. 7  is a flowchart showing the steps of an exemplary method. 
         FIG. 8  is a perspective view an example casting core used in the method for casting an exhaust manifold. 
         FIG. 9  is cross-sectional view from the perspective of the first distal end of an example casting core used in the method for casting an exhaust manifold. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, may be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure. 
       FIG. 1-6  illustrate multiple perspective and cross-sectional views of an exemplary exhaust manifold  100 . The first lateral side of the exterior wall  120  can have a plurality of air pocket indentation  121 - 125 . The first lateral side of the exterior wall  120  can be the side of the exemplary exhaust manifold  100  that connects with the engine. The air pocket indentations  121 - 125  can be disposed between the exhaust gas inlets  131 - 136 . In use, the air pocket indentations  121 - 125  are not exposed while the exhaust manifold  100  is attached to an engine. Because the air pocket indentations  121 - 125  are not exposed during use, these air pocket indentations  121 - 125  do not have to comply with the skin surface temperature safety regulations. The air pocket indentations  121 - 125  can also provide internal support for the formation of the exhaust gas inlets  131 - 136  during production of the exhaust manifold  100 . The exhaust manifold  100  can be produced through sand casting as detailed below when describing exemplary method  200  and  FIG. 7 . During the sand casting process the air pocket indentations  121 - 125  can allow a reduced number of cores to be required during the casting process and can further simplify the shape of the cores necessary to create the exhaust manifold  100 . 
     The present disclosure contemplates embodiments of the exemplary exhaust manifold  100  where different amounts of the exhaust gas inlets  131 - 136  on the first lateral side of the exterior wall  120  of the exemplary exhaust manifold  100  are incorporated in the exemplary exhaust manifold  100 . The number of exhaust gas inlets  131 - 136  can be dependent upon the number of engine cylinders in the engine to which the exemplary exhaust manifold  100  is coupled. As the number of exhaust gas inlets  131 - 136  is altered the number of air pocket indentations  121 - 125  can be altered accordingly. 
     As shown in  FIGS. 1 ,  2 ,  4 , and  5  the exemplary exhaust manifold  100  can have an exhaust outlet  137  at the first distal end of the exterior wall  150 . The exhaust outlet  137  can be part of an elbow portion  143  of the exemplary exhaust manifold  100  that bends around an axis on the top side of the exterior wall  127 . In other embodiments, the exhaust gas outlet  137  can be located at different locations on the exemplary exhaust manifold  100  to accommodate connections with other engine components, such as a turbocharger. The exemplary exhaust manifold  100  can have a coolant inlet port  141  on the second distal end of the exterior wall  152 . The exemplary exhaust manifold  100  can have a first coolant outlet port  142  on the top side of the exterior wall  127 . The exemplary exhaust manifold can have a second coolant outlet port  143  on the bottom side of the exterior wall  128 . 
     As shown in  FIGS. 3 ,  5 , and  6 , the interior of the exemplary exhaust manifold  100  can have a longitudinal exhaust gas passageway  130  that runs longitudinally from the second distal end of the exterior wall  152  to the first distal end of the exterior wall  150 . The exemplary manifold  100  can have a longitudinal coolant passageway  140  that runs longitudinally from the second distal end of the exterior wall  152  to the first distal end of the exterior wall  150 . The longitudinal exhaust gas passageway  130  and the longitudinal coolant passageway  140  can be separated by a longitudinal interior wall  138 . 
     The exemplary exhaust manifold  100  can have multiple sensor ports on the exterior walls of the exemplary exhaust manifold  100 . As shown in  FIGS. 1 and 2  a temperature sensor port  162  can allow for the temperature of the coolant used for cooling within the exemplary exhaust manifold  100  to be measured. The temperature port  162  is shown in  FIG. 1  on the top side of the exterior wall  127  of the exemplary exhaust manifold  100 , but can be located anywhere on the exterior wall of the exemplary exhaust manifold  100 . In other embodiments of the disclosed invention, multiple temperature ports  162  can be used to measure the exemplary exhaust manifold&#39;s exterior wall skin temperature, the temperature of the coolant, or the temperature of the exhaust gas. Sensors used in the temperature ports  161  can be in communication with a switch located on the exemplary exhaust manifold  100 . The switch can be secured to the exemplary exhaust manifold  100  using a first switch attachment mechanism  163  and possibly a second attachment mechanism  164 . There can be multiple switches in communication with multiple temperature sensors during the operations of the exhaust manifold. If the temperature of the exemplary exhaust manifold&#39;s exterior wall skin, the exhaust gas, or the coolant rises above or falls below threshold values the switch may alter the operation of the exhaust manifold or shut down the engine system including the exhaust manifold. 
     As shown in  FIGS. 1 ,  2 , and  4  a pressure port  161  can allow for the pressure of the coolant within the exemplary exhaust manifold  100  to be measured. The pressure port  161  is shown in  FIG. 1  on the second distal end of the exterior wall  152  of the exemplary exhaust manifold  100 , but can be located anywhere on the exterior wall of the exemplary exhaust manifold  100 . In other embodiments of the disclosed invention, multiple pressure ports  161  can be used to measure the pressure of the coolant or the pressure of the exhaust gas. Sensors used in the pressure ports  161  can be in communication with a switch located on the exemplary exhaust manifold  100  and secured by a first switch attachment mechanism  163  and possibly a second attachment mechanism  164 . There can be multiple switches in communication with multiple pressure sensors during the operations of the exhaust manifold. If the pressure of the exhaust gas or coolant rises above or falls below threshold values the switch may alter the operation of the exhaust manifold or shut down the engine system including the exhaust manifold. 
     As shown in  FIGS. 1 ,  2 ,  4 , and  5  a mounting attachment mechanism  165  can be located on the top side of the exterior wall  127  of the exemplary exhaust manifold  100 . The mounting attachment mechanism  165  can be used to secure the exemplary exhaust manifold  100  to other parts of an engine system. The present disclosure contemplates multiple mounting attachment mechanisms  165  for securing the exemplary exhaust manifold  100  to multiple parts of an engine system. 
     As shown in  FIGS. 1 ,  2 ,  4 , and  5  bolt holes  180  can be located on the first lateral side of the exterior wall  120  of the exemplary exhaust manifold  100 . The bolt holes  180  can traverse the body of the exemplary exhaust manifold  100  extending from the second lateral side of the exterior wall  126  to the first lateral side of the exterior wall  120 . The bolt holes  180  can be utilized to secure the exemplary exhaust manifold  100  to the engine head. The present disclosure contemplates bolt holes  180  located at various intervals and locations within the exemplary exhaust manifold  100  and exiting the exemplary exhaust manifold  100  at various intervals and locations on the first lateral side of the exterior wall  120 . 
     As shown in  FIGS. 1 and 4  the exemplary exhaust manifold  100  can have sand core plug ports  170 . The sand core plug ports  170  can be used to extract the sand cores used during the casting process. The sand core plug ports  170  can be located on the first lateral side of the exterior wall  120  or at different locations on the exterior wall of the exemplary exhaust manifold  100 . The location of the sand core plug ports  170  can be altered to simplify the casting process as needed. 
     During operation, the exemplary exhaust manifold  100  can transfer exhaust gas from an engine to a turbocharger or to another engine system component. The engine, to which the exemplary exhaust manifold  100  can be coupled, can be an engine for many types of machines, such as machines in a marine environment, mining machines, or excavation machines. The exhaust gas inlets  131 - 136  can take in exhaust gas from corresponding engine cylinder outlets. The exhaust gas enters the exhaust manifold through the exhaust gas inlets  131 - 136 . Next the exhaust gas merges from the exhaust gas inlets  131 - 136  into the longitudinal exhaust gas passageway  130 . The exhaust gas can travel down the longitudinal exhaust gas passageway  130  and out the exhaust gas outlet  137 . After the exhaust gas exits through the exhaust gas outlet  137  it can enter a turbocharger where the exhaust gas is used to drive a turbine. Thus, the exhaust manifold  100  can transfer and direct the exhaust gas from an engine to a turbocharger. 
     During operation, the exhaust manifold  100  can be cooled by engine coolant, such as water or glycol mixture. The coolant can enter the exemplary exhaust manifold  100  through the coolant inlet port  141 . The coolant can be pumped into the exemplary exhaust manifold  100  through the coolant inlet port  141 . The coolant temperature and pressure can be monitored through a temperature sensor port  161  and a pressure sensor port  162 . After the coolant passes through the coolant inlet port  141  it can travel through the longitudinal coolant passageway  140  formed by portions of the exterior wall and the longitudinal interior wall  138 . The coolant can exit the exemplary exhaust manifold  100  through either a first coolant outlet port  142 , which can be located on the top side of the exterior wall  127 , or through the second coolant outlet, which can be located on the bottom side of the exterior wall  128 . In some embodiments the coolant that exits through the first coolant outlet port  142  can travel to the turbocharger, which can be driven by the exhaust gas that exits the exemplary exhaust manifold  100  at the exhaust gas outlet  137 , where the coolant can again cool the skin temperature of the turbocharger. In some embodiments the coolant that exits through the second coolant outlet port  143  can be circulated through a general engine cooling system. The present disclosure contemplates multiple embodiments with various coolant outlet ports delivering coolant to various engine components. 
     As shown in the flowchart in  FIG. 7  the present disclosure contemplates an exemplary method of casting an exhaust manifold  200 . The method can produce the exemplary exhaust manifold  100  disclosed above. The exemplary method of casting  200  can involve aligning an exhaust manifold mold in a casting flask. The exhaust manifold mold can be made of metal or the exhaust manifold mold can also be made of sand and can be formed by inserting an exhaust manifold pattern into the casting flask to render an imprint of the exterior of the manifold pattern. The exhaust manifold mold, whether made of metal or sand, can include a plurality of air pocket indentations located on the first lateral side of the exterior wall of the exhaust manifold mold. The air pocket indentations in the mold render the air pocket indentations  121 - 125  disclosed in the exemplary exhaust manifold  100  above. 
     The exemplary method of casting  200  can involve inserting a coolant passage core  231  and an exhaust passage core within the exhaust manifold mold. The casting flask can be two parts with a top part, known as a cope, and bottom part, known as a drag. The exhaust manifold mold can also come in two parts with a bottom part that rests in the drag of the casting flask and top part that rests in the cope of the casting flask. The coolant passage core  231  and the exhaust passage core can be laid within the bottom part of the exhaust manifold mold and then enclosed by sealing the casting flask by laying the top part of the exhaust manifold mold in the cope of the casting flask over the bottom part of the exhaust manifold mold in the drag of the casting flask. 
     In the exemplary method of casting  200  the exhaust passage core can be inserted into the exhaust manifold mold prior to inserting the coolant passage core  231  into the exhaust manifold mold. The exhaust passage core can have a generally cylindrical shape and include a plurality of protrusions. The exhaust passage core can be inserted within the mold such that the plurality air pocket extensions of the mold are disposed between the plurality of protrusions of the exhaust passage core. 
     As shown in  FIGS. 8 and 9 , the coolant passage core  231  can be generally U-shaped and extend longitudinally. The coolant passage core  231  can be inserted into the mold such that the plurality air pocket extensions of the exhaust manifold mold and the exhaust passage core are surrounded by the coolant passage core  231 . The coolant passage core can have a plurality of sand core plugs  232  extending from the generally U-shaped frame. The sand core plugs  232  can correspond with the sand core plug ports  170  on the exemplary exhaust manifold  100 . The coolant passage core  231  can include first coolant outlet core plugs  234  that correspond with the first coolant outlet port  142  of the exemplary exhaust manifold  100 . The present disclosure contemplates multiple embodiments of the coolant passage core  231  with multiple core plugs corresponding to multiple coolant outlets ports, coolant inlets ports, exhaust gas outlets, exhaust gas inlets, sensor ports, and other ports that could be required on the exemplary exhaust manifold  100 . The coolant passage core  231  can include bolt grooves  233  that correspond to the bolt holes  180  in the exemplary exhaust manifold  100 . 
     The exemplary method of casting  200  can involve pouring a liquid metal into the sealed casting flask. The liquid metal can be an aluminum alloy or another metallic alloy, such as cast or ductile iron. The aluminum alloy can have varying percentages of aluminum, silicon, iron, copper, manganese, magnesium, zinc, titanium, lead, or other elements. The exemplary method of casting  200  can involve allowing the liquid metal to solidify into a solid metal piece. The exemplary method of casting  200  can involve removing the exhaust manifold mold and the cores from casted exhaust manifold. As disclosed above the cores can be extracted through the sand core plug ports  170  in the exemplary exhaust manifold  100 . 
     INDUSTRIAL APPLICABILITY 
     The present disclosure is applicable to engine systems that require an exhaust manifold that is coolant cooled. Often these engine systems are found in marine environments. The disclosed exemplary exhaust manifold  100  can be used to direct exhaust gas from engine cylinders to a turbocharger where the exhaust gas is used to generate additional power. The exemplary exhaust manifold  100  can also direct the cooling coolant that is pumped into the exemplary exhaust manifold  100  to other components of the engine system 
     The disclosed exemplary method of casting an exhaust manifold  200  is applicable to the manufacturing process required to create the exemplary exhaust manifold  100 . The disclosed exemplary method of casting an exhaust manifold  200  uses only two cores during the casting process, which can be less complex and more cost effective for manufacturing. Using only two cores, rather than three or more cores as in prior methods for casting exhaust manifolds, there is at least one less sand core that needs to be produced and secured during the pouring of the casting. In past methods two cooling cores had to be joined to form a cooling jacket. Using two separate cooling cores to create a single cooling jacket, can result in a seam which could result in leakage from the cooling jacket into other portions of the exhaust manifold. The location of the air pocket indentations  121 - 125  in the exhaust manifold mold will also serve to avoid a large solid section of metal on the first lateral side of the exterior wall  120  of the exemplary exhaust manifold  100 . During the casting process a large solid section of metal in the mold can create a high risk of porosity in the casting due to variance in the solidifying cooling times between the metal towards the interior of the exemplary exhaust manifold  100  and metal on the towards the exterior surfaces of the exemplary exhaust manifold  100 . 
     The present disclosure includes other aspects, objects, and advantages of the present invention can be obtained from a study of the drawings, the disclosure, and the claims. It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.