Patent Publication Number: US-11035333-B1

Title: Duct assembly for fuel injection systems in engines

Description:
TECHNICAL FIELD 
     The present disclosure relates to a fuel injection system for an internal combustion engine. More particularly, the present disclosure relates to a duct assembly for the fuel injector system. 
     BACKGROUND 
     In internal combustion engines, a combustion chamber is commonly defined between a cylinder head and a piston. In some applications, fuel for combustion is injected as a fuel jet into the combustion chamber by, for example, a fuel injector. Fuel injectors typically include orifices through which a quantity of fuel may pass through to be injected and introduced into the combustion chamber. A manner in which the injected fuel mixes and/or interacts with air and other environmental elements of the combustion chamber may impact the combustion process and emissions. The manner in which the fuel jet is injected may impact or affect the amount of soot formation within the combustion chamber. 
     Duct structures may be provided in combustion engines to control the mixing of the fuel jets, delay ignition, and reduce soot formation within the combustion chamber. A duct structure may include multiple ducts arranged (e.g., in the form of a circular array) around the fuel injector such that the ducts may receive corresponding fuel jets from corresponding orifices of the fuel injector. The ducts control an interaction and/or mixing of the fuel jets, which in turn, may reduce the amount of soot formed in the combustion chamber. To attain such interaction and/or mixing of the fuel jets, the ducts should possess a desired geometry and need to be deployed at an optimum angle with respect to the fuel jets. Attaining such geometry and angle of the ducts is difficult and requires complex manufacturing processes, and such difficulty is exacerbated if an increased number of ducts were required around the fuel injector. 
     U.S. Pat. No. 8,967,129 relates to an internal combustion engine that includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston within the cylinder bore has a piston crown portion facing the flame deck surface to define a combustion chamber therebetween. A fuel injector is configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. A duct is defined in the combustion chamber between the piston crown and the flame deck surface that has a generally rectangular cross section and extends in a radial direction relative to the cylinder bore substantially along the fuel jet centerline. 
     SUMMARY OF THE INVENTION 
     In one aspect, the disclosure is directed to a duct assembly for a fuel injector of an engine. The duct assembly includes a base and multiple duct bodies. The base is configured to be coupled to a cylinder head of the engine and includes a number of spaced apart receptacles. Each receptacle defines a cavity that in turn defines a receptacle axis, a rotational engagement surface, and an axial engagement surface. The duct bodies are correspondingly secured within cavities defined by the spaced apart receptacles. Each duct body defines an axis and a duct extending therethrough along the axis to provide a passage for a corresponding fuel jet discharged from the fuel injector. Each duct body defines an axial alignment surface engaging the axial engagement surface of the receptacle in which it is disposed to axially align the duct body along the receptacle axis of the corresponding receptacle. 
     In another aspect, the disclosure is related to a fuel injection system for an engine. The fuel injection system includes a fuel injector configured to discharge fuel jets into a combustion chamber of the engine. The fuel injection system also includes a duct assembly for the fuel injector. The duct assembly includes a base and multiple duct bodies. The base is configured to be coupled to a cylinder head of the engine and includes a number of spaced apart receptacles. Each receptacle defines a cavity that in turn defines a receptacle axis, a rotational engagement surface, and an axial engagement surface. The duct bodies are correspondingly secured within cavities defined by the spaced apart receptacles. Each duct body defines an axis and a duct extending therethrough along the axis to provide a passage for a corresponding fuel jet discharged from the fuel injector. Each duct body defines an axial alignment surface engaging the axial engagement surface of the receptacle in which it is disposed to axially align the duct body along the receptacle axis of the corresponding receptacle. 
     In yet another aspect, the disclosure is directed to an engine. The engine includes a cylinder defining a bore, a piston slidably disposed within the bore and defining a piston crown, a cylinder head coupled to the cylinder and defining a flame deck surface, and a combustion chamber defined between the flame deck surface and the piston crown. The engine further includes a fuel injector and a duct assembly for the fuel injector. The fuel injector is configured to discharge fuel jets into the combustion chamber. The duct assembly includes a base and multiple duct bodies. The base is coupled to the cylinder head and includes a number of spaced apart receptacles. Each receptacle defines a cavity that in turn defines a receptacle axis, a rotational engagement surface, and an axial engagement surface. The duct bodies are correspondingly secured within cavities defined by the spaced apart receptacles. Each duct body defines an axis and a duct extending therethrough along the axis to provide a passage for a corresponding fuel jet discharged from the fuel injector. Each duct body defines an axial alignment surface engaging the axial engagement surface of the receptacle in which it is disposed to axially align the duct body along the receptacle axis of the corresponding receptacle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  a sectional view of an engine including a fuel injection system, in accordance with an aspect of the present disclosure; 
         FIG. 2  is a perspective view of a duct assembly associated with a fuel injector of the fuel injection system, in accordance with an aspect of the present disclosure; 
         FIG. 3  is a bottom view of the duct assembly including a base and a number of duct bodies secured to a corresponding number of receptacles of the base, in accordance with an aspect of the present disclosure; 
         FIG. 4  is a perspective view of the base of the duct assembly with the duct bodies removed, in accordance with an aspect of the present disclosure; 
         FIG. 5  is an enlarged perspective view of one of the receptacles of the base, in accordance with an aspect of the present disclosure; 
         FIG. 6  is a cross-sectional view of one of the duct bodies secured within a cavity of one of the receptacles of the base taken generally along line  6 - 6  in  FIG. 9 , and in accordance with an aspect of the present disclosure; 
         FIG. 7  is a cross-sectional perspective view of the duct assembly taken generally along line  7 - 7  in  FIG. 3 , illustrating various details associated with the assembly and securement of a duct body within a cavity of a receptacle, in accordance with an aspect of the present disclosure; 
         FIG. 8  is a diagrammatic sectional view of a process for assembling one of the duct bodies within the cavity of the one of the receptacles of the base, in accordance with an aspect of the present disclosure; 
         FIG. 9  is a view illustrating an assembled state of the duct body within the cavity of the one of the receptacles of the base, in accordance with an aspect of the present disclosure; 
         FIG. 10  is cross-sectional view of an assembly of a duct body and a receptacle, illustrating variations in the duct body and the receptacle of  FIGS. 1 to 9 , in accordance with an aspect of the present disclosure; 
         FIG. 11  is a cross-sectional view of an assembly of the duct body of  FIG. 10  within a receptacle that is a variant of the receptacle of  FIG. 10 , in accordance with an aspect of the present disclosure; 
         FIG. 12  is a is a cross-sectional view of an assembly of the duct body of  FIG. 10  within a receptacle that is a variant of the receptacle of  FIG. 11 , in accordance with an aspect of the present disclosure; and 
         FIG. 13  is a receptacle that is a variant of the receptacle described in  FIGS. 1 to 9 , in accordance with an aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Generally, corresponding reference numbers will be used throughout the drawings to refer to the same or corresponding parts. Also, wherever possible, same reference numbers will be used throughout the drawings to refer to the same or the like parts. 
     Referring to  FIG. 1 , an engine  100  is shown. The engine  100  may be an internal combustion engine  104  and may include any of a diesel engine, a gasoline engine, a gas engine, a two-stroke engine, a four-stroke engine, a dual fuel engine, or any other similar internal combustion engine known in the art. The engine  100  may be used in any application including construction and mining machines, such as excavators, shovels, loaders, off-highway trucks, dozers, as well as stationary power generation units and marine vessels. 
     The engine  100  includes a cylinder  112  that defines a bore  116 . The bore  116  extends from an end  120  (e.g., an upper end) of the cylinder  112  to another end (e.g., a lower end) (not shown) of the cylinder  112 . The engine  100  includes a piston  124  that is slidably disposed within the bore  116 . The piston  124  may be configured to reciprocate within the bore  116  between a top dead center (TDC) and a bottom dead center (BDC). Further, the piston  124  defines a piston crown  128  (which may include a bowl portion, for example) and may also define other features, such as a piston skirt  132 . The piston skirt  132  may define a number of grooves (only one groove  144  is annotated) to receive piston rings  136  that may interact with a cylinder wall  140  defining the bore  116 . 
     The engine  100  also includes a cylinder head  148  that is coupled to the end  120  of the cylinder  112 . The cylinder head  148  defines a flame deck surface  158  that, upon assembly of the cylinder head  148  to the end  120 , may face the piston crown  128 . A combustion chamber  162  of the engine  100  is defined between the flame deck surface  158  and the piston crown  128 . In other words, the combustion chamber  162  is bound and/or delimited at one end by the flame deck surface  158  of the cylinder head  148 , and bound and/or delimited at another end by the piston crown  128  of the piston  124 . The combustion chamber  162  is also bound and/or delimited by a portion of the cylinder wall  140  that defines the bore  116 . 
     Further, the cylinder head  148  includes one or more intake conduits (e.g., intake conduit  166 ) and one or more exhaust conduits (e.g., exhaust conduit  170 ). The intake conduits facilitate an intake of charge (that may include one or more of air, exhaust gas, natural gas, or other fuels) into the combustion chamber  162 , while the exhaust conduits facilitate a discharge or exit of exhaust gases from the combustion chamber  162 . One or more intake valves (e.g., intake valve  174 ) may be provided to regulate an influx of the charge into the combustion chamber  162  through the intake conduits, and, similarly, one or more exhaust valves (e.g., exhaust valve  178 ) may be provided to regulate discharge or exit of exhaust gases of combustion from the combustion chamber  162  through the exhaust conduits. 
     The engine  100  also includes a connecting rod  182 . The connecting rod  182  is coupled to the piston  124  to move and reciprocate as the piston  124  moves and reciprocates between the TDC and BDC. The connecting rod  182  may also be coupled to a crankshaft (not shown) at one end to power a rotation of the crank shaft, and, in turn by which output (e.g., rotary power output) may be generated by the engine  100 . Although the above aspects are discussed with respect to a single cylinder (i.e., cylinder  112 ) the engine  100  may include multiple cylinders, and to each of which discussions ascribed to the cylinder  112  may be equivalently and appropriately applied. 
     With continued reference to  FIG. 1 , the engine  100  includes a fuel injection system  190 . The fuel injection system  190  includes a fuel injector  194  and a duct assembly  198  for the fuel injector  194 . 
     The fuel injector  194  is configured to inject fuel into the combustion chamber  162  during engine operations. The fuel injector  194  includes an injector body  202  with a tip portion  206  disposed at an end  210  of the injector body  202 , as shown. The fuel injector  194  may be mounted to the cylinder head  148  and may pass through the cylinder head  148  such that the tip portion  206  of the injector body  202  may protrude and extend into the combustion chamber  162 . In that manner, the combustion chamber  162  may be in fluid communication with the tip portion  206  of the fuel injector  194  and may receive fuel from the fuel injector  194 . The tip portion  206  includes a number of orifices  214  (six orifices according to an exemplary embodiment of the present disclosure out of which only two orifices, i.e., orifice  216  and orifice  218  are shown). Fuel may pass through the injector body  202  and exit the orifices as fuel jets that are introduced into the combustion chamber  162  for combustion. The orifices  214  may be higher or a lower in number than the six referenced above. Further, the orifices  214  may be arrayed around a longitudinal axis  220  of the fuel injector  194 , as shown. 
     Referring to  FIGS. 1, 2, and 3 , the duct assembly  198  is configured to control the mixing of the fuel jets to reduce soot formation within the combustion chamber  162 . In this regard, the duct assembly  198  includes a base  222  and multiple duct bodies  226 ′,  226 ″,  226 ′″,  226 ″″,  226 ′″″,  226 ″″″ (collectively, duct bodies  226 ), as shown. The duct assembly  198  is configured to be positioned with respect to the fuel injector  194  such that the duct bodies  226  are arrayed around the tip portion  206  with the duct bodies  226  being correspondingly aligned with respect to the orifices  214  of the fuel injector  194  disposed at the tip portion  206  (e.g., see duct body  226 ′ aligning with respect to orifice  216  in  FIG. 1 ). In so doing, the duct bodies  226  receive the fuel jets from the corresponding orifices  214  and facilitate the mixing of the fuel jets for facilitating combustion. Further details with regard to the duct assembly  198  are discussed below. 
     Referring to  FIGS. 2, 3, and 4 , the base  222  of the duct assembly  198  may include an annular or ring-shaped portion  230  that defines a base axis  234 , a first axial base end  238 , and a second axial base end  242  disposed opposite to the first axial base end  238 , an outer periphery  246 , and an inner periphery  250 . The ring-shaped portion  230  may include a number of slots  254 ′,  254 ″,  254 ′″. Collectively, the slots  254 ′,  254 ″,  254 ′″ may be referred to as a slots  254 , with each of the slots  254  extending between the first axial base end  238  and the second axial base end  242  of the ring-shaped portion  230 . A shape and profile of the slots  254  may differ from what is depicted, and, thus, need to be seen as exemplary. In one example, the slots  254  may be circular shaped (i.e., shaped as holes) that extend between the first axial base end  238  and the second axial base end  242 . As an example, the slots  254  may be three in number, as shown, although a higher or a lower number of slots  254  may be contemplated. Further, the slots  254  may be arrayed equidistantly around the base axis  234 , although a variation in the arrangement of the slots  254  is possible. 
     The slots  254  may receive fasteners  258  (e.g., threaded fasteners, such as bolts or screws) such that the fasteners  258  may be used to engage and couple the ring-shaped portion  230  (and thus the base  222 ) to the flame deck surface  158  of the cylinder head  148 . In one example, the fasteners  258  may be inserted into the slots  254  from the second axial base end  242  towards the first axial base end  238  such that the fasteners  258  (i.e., head portions of the fasteners  258 ) may engage the second axial base end  242  of the ring-shaped portion  230  and a length thereof (e.g., threaded shank portions of the fasteners  258 ) is driven into a receptacle (e.g., receiving holes such as tapped holes) of the flame deck surface  158  so as to engage and retain the ring-shaped portion  230  and thus the base  222  to the flame deck surface  158  of the cylinder head  148 . Said portion of the flame deck surface  158  may be a portion of the flame deck surface  158  defined around the tip portion  206  of the fuel injector  194 . By way of such assembly, the first axial base end  238  may abut and rest against the flame deck surface  158  of the cylinder head  148 , while the second axial base end  242  may be directed away from the flame deck surface  158  of the cylinder head  148  to face and be exposed to the combustion chamber  162  of the engine  100 . 
     The base  222  includes a number of spaced apart receptacles (or simply, receptacles  262 , hereinafter). The receptacles  262  are disposed on the second axial base end  242  of the ring-shaped portion  230  that is directed away from the flame deck surface  158  of the cylinder head  148  and is exposed to the combustion chamber  162  of the engine  100 . As an example, the base  222  includes six receptacles  262 ′,  262 ″,  262 ′″,  262 ″″,  262 ′″″,  262 ″″″, although a lesser or a higher number of receptacles  262  may be contemplated. The receptacles  262  may be equidistantly spaced apart on the second axial base end  242  and rotationally arrayed around the base axis  234 . The receptacles  262 ′,  262 ″,  262 ′″,  262 ″″,  262 ′″″,  262 ″″″ define corresponding cavities  266 ′,  266 ″,  266 ′″,  266 ″″,  266 ′″″,  266 ″″″ therein to correspondingly receive and secure the duct bodies  226 ′,  226 ″,  226 ′″,  226 ″″,  226 ′″″,  226 ″″″ therein, i.e., one receptacle (e.g., receptacle  262 ″) receives and secures one duct body (e.g., duct body  226 ″) in its cavity (e.g., cavity  266 ″). The disclosure below highlights further details of the duct bodies  226  and the receptacles  262 . Such details may be discussed by reference to the duct body  226 ″ and to the receptacle  262 ″—said details and discussions may be suitably applied to each of the other remaining duct bodies  226  and receptacles  262 , as well. For ease and simplicity, the duct body  226 ″ and the receptacle  262 ″ may respectively be referred to as the duct body  226  and the receptacle  262 . The cavity  266 ″ of the receptacle  262  may also be simply referred to as cavity  266 . Wherever required, references to the duct bodies  226  and the receptacles  262  by way of their individual annotations, as have been assigned above, may also be used. 
     Referring to  FIG. 5 , the receptacle  262  includes a U-shaped portion  270  and a post portion  274 . The U-shaped portion  270  defines a floor portion  278  and a pair of resilient or deflectable arms  282 , including a first arm  282 ′ and a second arm  282 ″, while the post portion  274  extends between the floor portion  278  and the ring-shaped portion  230  to support the floor portion  278  (and, in turn, the U-shaped portion  270 ) on the ring-shaped portion  230 , as shown. In one example, the receptacle  262  (including the U-shaped portion  270  and the post portion  274 ) in conjunction with the ring-shaped portion  230  may be all formed together as a single piece, helping the base  222  attain a unitary, integrated structure. Also, the base  222  may be made from a metallic material, although it is possible for the base  222  to be made from a combination of materials—for example, the base  222  may be made from an alloy. Although not limited, manufacturing processes, such as MIM (metal injection molding) process, progressive stamping, and 3D printing, may be used to produce the base  222 . 
     Both the first arm  282 ′ and the second arm  282 ″ extend away from the floor portion  278 . As shown, the first arm  282 ′ and the second arm  282 ″ extend in the same direction (e.g., upwards or generally along the base axis  234 , see  FIG. 4 ) away from the second axial base end  242  of the ring-shaped portion  230  to respectively define a first top edge  284 ′ and a second top edge  284 ″, as depicted. The first top edge  284 ′ and the second top edge  284 ″ are spaced apart from each other by a distance, D 1 , and define a mouth  288  of the cavity  266  through which the duct body  226  may be inserted and secured within the cavity  266 . 
     The first arm  282 ′ and the second arm  282 ″ also define corresponding inner surfaces (i.e., a first arm inner surface  286 ′ and a second arm inner surface  286 ″) that face each other. As shown, both the first arm inner surface  286 ′ and the second arm inner surface  286 ″ extend respectively from the first top edge  284 ′ and the second top edge  284 ″ and extend further towards the floor portion  278 . Each of the first arm inner surface  286 ′ and the second arm inner surface  286 ″ define a curved or an arcuate profile, with concavities defined by said arcuate profiles facing each other, as well. Also, as an example, the arcuate profile defined by the first arm inner surface  286 ′ may be similar (or congruous) to the arcuate profile defined by the second arm inner surface  286 ″. Further, the concavities defined by the first arm inner surface  286 ′ and the second arm inner surface  286 ″ may be defined around a common axis  290 , as well. The common axis  290  may be referred to as a receptacle axis  294  of the receptacle  262  defined by the cavity  266  of the receptacle  262 , or simply, the ‘receptacle axis  294 ’, hereinafter. The receptacle axis  294  meets the base axis  234  at a point  298  and defines an inclination (see angle, A) with respect to the base axis  234  (see  FIG. 7 ). 
     As shown, the floor portion  278 , the first arm inner surface  286 ′ and the second arm inner surface  286 ″, each define corresponding lengths that extend along the receptacle axis  294 , in and along a radial direction defined between the outer periphery  246  and the inner periphery  250  of the ring-shaped portion  230  of the base  222 . As may be noted, the floor portion  278  along with the first arm  282 ′ and the second arm  282 ″ together define the cavity  266  of the receptacle  262 . In some embodiments, a cross-section of the cavity  266  defined along the receptacle axis  294  may be uniform. The distance, D 1 , may also be uniform along the receptacle axis  294 . The cavity  266  further defines a rotational engagement surface  302  and an axial engagement surface  306 . 
     Referring to  FIGS. 5 and 6 , the axial engagement surface  306  includes corresponding lateral side edges  310  of the first arm  282 ′ and the second arm  282 ″. For example, the lateral side edges  310  of the first arm  282 ′ includes a first lateral side edge  314 ′ and a second lateral side edge  318 ′. Similarly, the lateral side edges  310  of the second arm  282 ″ include a first lateral side edge  314 ″ and a second lateral side edge  318 ″. The first lateral side edges  314 ′,  314 ″ are relatively closer to the inner periphery  250  than to the outer periphery  246  of the ring-shaped portion  230 , while the second lateral side edges  318 ′,  318 ″ are relatively closer to the outer periphery  246  than to the inner periphery  250  of the ring-shaped portion  230 . As shown, a distance, E 1 , is defined between the first lateral side edge  314 ′ and the second lateral side edge  318 ′ of the first arm  282 ′ and a distance, E 2 , is defined between the first lateral side edge  314 ″ and the second lateral side edge  318 ″ of the second arm  282 ″. In one example, both the distances, E 1  and E 2 , are equal to each other. In some embodiments, the axial engagement surface  306  may refer to or include only one of: the first lateral side edge  314 ′ and the second lateral side edge  318 ′ of the first arm  282 ′; or the first lateral side edge  314 ″ and the second lateral side edge  318 ″ of the second arm  282 ″. 
     With regard to the rotational engagement surface  302  of the receptacle  262 , the rotational engagement surface  302  includes a first receptacle flat surface  322  disposed on the floor portion  278  of the U-shaped portion  270 . The first receptacle flat surface  322  extends (e.g., uninterruptedly) along the receptacle axis  294  across the floor portion  278 . 
     Referring to  FIG. 5 , at least one of the first arm  282 ′ or the second arm  282 ″ is deflectable with respect to the floor portion  278  to make way and allow for an insertion and assembly of the duct body  226  into the cavity  266  of the receptacle  262 . In the disclosed embodiment, both the first arm  282 ′ and the second arm  282 ″ are deflectable with respect to the floor portion  278 . The deflectable nature of the first arm  282 ′ and the second arm  282 ″ also enables the first arm  282 ′ and the second arm  282 ″ to resiliently engage a portion of the duct body  226  and secure the duct body  226  therebetween. During an assembly of the duct body  226  into the cavity  266  of the receptacle  262  through the mouth  288 , the distance, D 1 , may change (e.g., increase) owing to said deflectable nature of the first arm  282 ′ and the second arm  282 ″. Discussions related to such an assembly of the duct body  226  into the cavity  266  of the receptacle  262  is provided later in the present disclosure. 
     According to an aspect of the present disclosure, the U-shaped portion  270  defines corresponding grooves at an interface between the floor portion  278  and each of the first arm  282 ′ and the second arm  282 ″. For example, the U-shaped portion  270  defines a first groove  320  between the first arm  282 ′ and the floor portion  278  and defines a second groove  324  between the second arm  282 ″ and the floor portion  278 . The first groove  320  and the second groove  324  relieve stress from the corresponding interfaces during a deflection of the first arm  282 ′ and the second arm  282 ″. The first groove  320  and the second groove  324  also provide flexibility to the first arm  282 ′ and the second arm  282 ″. 
     Referring to  FIG. 6 , the duct body  226  of the duct assembly  198  is configured to be received and secured within the cavity  266  of the receptacle  262 . The duct body  226  may include an elongated cylindrically shaped profile, as shown. The duct body  226  defines an axis (referred to as a duct axis  326 , hereinafter) and a duct  330  extending therethrough along the duct axis  326  to provide a passage for a corresponding fuel jet discharged from one of the orifices  214  of the fuel injector  194 . As shown, the duct body  226  may include a first axial end  334  and a second axial end  338  opposite to the first axial end  334 . A first axial end face  342  is defined at the first axial end  334  while a second axial end face  346  is defined at the second axial end  338 . 
     According to an aspect of the present disclosure, the duct body  226  also defines an outer surface  350 . The outer surface  350  may include a straight part  352  and a tapering part  356 . For example, the straight part  352  extends from the first axial end  334  towards the second axial end  338  and the tapering part  356  extends from the straight part  352  to the second axial end  338 . Further, an inner surface  354  of the duct body  226  is defined by the duct  330  extending through the duct body  226 . As shown, the duct  330  extends from the first axial end  334  to the second axial end  338  and defines an arcuate inlet surface  358  at the first axial end  334  to receive the corresponding fuel jet from the first axial end  334  and a sharp edged outlet  362  at the second axial end  338  to expel the corresponding fuel jet through the second axial end  338 . 
     The arcuate inlet surface  358 , according to an aspect of the present disclosure, extends from the inner surface  354  all the way to the outer surface  350  in the form of a circular arc (in cross-section) or defines an arcuate cross-section, as shown. The arcuate inlet surface  358  eases receipt of the corresponding fuel jet into the duct  330 . In one example, the arcuate inlet surface  358  is 180 degrees rounded in cross-section or profile. In some embodiments, the arcuate inlet surface  358  may be configured with an arcuate cross-section less than 180 degrees but greater than 90 degrees. Providing a cross-section greater than 90 degrees may improve the flow of the air into the duct  330 . In one embodiment, the arcuate cross-section may be at least 150 degrees. In another embodiment, the arcuate cross-section may be at least 130 degrees. In still another embodiment, the arcuate cross-section may be at least 115 degrees. In each instance, the first 90 degrees is measured from the inner surface  354  of the duct  330  and the extent of the arcuate inlet surface  358  greater than 90 degrees extends from the first axial end  334  towards the outer surface  350  of the duct body  226 . 
     The sharp edged outlet  362  has a sharp edged cross-section or profile that defines an interface between the inner surface  354  of the duct body  226  and the second axial end face  346 . The inner surface of  354  of the duct  330  may define a constant cross-section along the duct axis  326  or along the duct&#39;s extension within the duct body  226 . However, in some embodiments, a non-constant cross-section, such as a varying cross-section of the duct  330  along the duct axis  326 , may be contemplated. 
     Referring to  FIGS. 2, 6, and 8 , the duct body  226  defines a rotational alignment surface  366 . The rotational alignment surface  366  includes a first duct flat surface  370 . The first duct flat surface  370  may be formed on the outer surface  350  of the duct body  226  and may extend from the first axial end  334  to the second axial end  338 , although it is possible for the first duct flat surface  370  to fall short or stop midway of a distance defined between the first axial end  334  and the second axial end  338 . 
     According to an embodiment of the present disclosure, the duct body  226  also defines a second duct flat surface  374  (also see  FIG. 3  and  FIG. 8 ) that is disposed diametrically opposite to the first duct flat surface  370 . In some embodiments, the second duct flat surface  374  may be similar (or congruous) in profile to the first duct flat surface  370 . Further, given that the second duct flat surface  374  is disposed diametrically opposite to the first duct flat surface  370 , the second duct flat surface  374  may be parallely defined with respect to the first duct flat surface  370 . Both the first duct flat surface  370  and the second duct flat surface  374  may be provided to reduce the vertical profile of the duct assembly  198  such as to provide sufficient clearance to the piston crown  128  (or the bowl portion) during engine operations. 
     Referring to  FIG. 6 , the duct body  226  further defines an axial alignment surface  378 . The axial alignment surface  378  of the duct body  226  includes axially spaced apart ridges  382  (or simply, ridges  382 ) along the outer surface  350  of the duct body  226 . For example, the axial alignment surface  378  includes two ridges  382 —a first ridge  386 ′ and a second ridge  386 ″, as shown in cross-section. The first ridge  386 ′ is disposed relatively proximal to the first axial end  334 , while the second ridge  386 ″ is disposed relatively distal from the first axial end  334 . In some embodiments, the axial alignment surface  378  includes another set of axially spaced apart ridges  394  (or simply, ridges  394 )—e.g., a third ridge  398 ′ and a fourth ridge  398 ″ defined diametrically opposite to the axially spaced apart ridges  382  or the first ridge  386 ′ and the second ridge  386 ″, as shown in cross-section. The third ridge  398 ′ is disposed relatively proximal to the first axial end  334 , while the fourth ridge  398 ″ is disposed relatively distal from the first axial end  334 . 
     A first straight surface  392  (i.e., extending straight along the duct axis  326 ) may be defined between the first ridge  386 ′ and the second ridge  386 ″. Similarly, a second straight surface  400  (i.e., extending straight along the duct axis  326 ) may be defined between the third ridge  398 ′ and the fourth ridge  398 ″. The first straight surface  392  may be disposed diametrically opposite to the second straight surface  400 . A distance, D 2 , may be defined between the first straight surface  392  and the second straight surface  400 , as shown. The distance, D 2 , may be defined along a diameter of the duct body  226  (also visualized in  FIG. 8 ). Also, distance, D 2 , is larger than distance, D 1  (see  FIG. 5 ). Further, a length defined by the first straight surface  392  along the duct axis  326  may be equal to the distance, E 1 , and a length defined by the second straight surface  400  along the duct axis  326  may be equal to the distance, E 2 . Given that, in an embodiment, the distances, E 1  and E 2 , are equal, lengths defined by the first straight surface  392  and the second straight surface  400 , along the duct axis  326 , may be equal as well. 
     In some embodiments, both the first ridge  386 ′ and the second ridge  386 ″ may extend partly circumferentially around the outer surface  350  (e.g., on the straight part  352  of the outer surface  350 ) of the duct body  226 . Similarly, both the third ridge  398 ′ and the fourth ridge  398 ″ may extend partly circumferentially around the outer surface  350  (e.g., on the straight part  352  of the outer surface  350 ) of the duct body  226 . In such a case, it may be further noted that portions of an outer surface  402 ,  406  of the first straight surface  392  and second straight surface  400 , respectively, may be curved (also see  FIG. 8 ) around the duct axis  326 , as well, and may be configured to engage the first arm inner surface  286 ′ and the second arm inner surface  286 ″ of the first arm  282 ′ and the second arm  282 ″ of the receptacle  262 , respectively, upon insertion of the duct body  226  into the receptacle  262 . In some embodiments, the first ridge  386 ′ may extend circumferentially around the outer surface  350  of the duct body  226  and may meet the third ridge  398 ′. Similarly, in some embodiments, the second ridge  386 ″ may extend circumferentially around the outer surface  350  of the duct body  226  and may meet the fourth ridge  398 ″. 
     In some embodiments, each of the first straight surface  392  and the second straight surface  400  may be recessed relative to other portions of the outer surface  350  of the duct body  226 , and, thus, the first straight surface  392  in conjunction with the first ridge  386 ′ and the second ridge  386 ″ may define a first recessed portion  390  of the duct body  226 . Similarly, the second straight surface  400  in conjunction with the third ridge  398 ′ and the fourth ridge  398 ′″ may define a second recessed portion  404  of the duct body  226 . 
     In some embodiments, the ridges  382  may be protuberances extending partly circumferentially outwards around the outer surface  350  (e.g., on the straight part  352  of the outer surface  350 ) of the duct body  226 . Similar discussions may be contemplated for the ridges  394 , as well. Further, like the base  222 , the duct body  226  may be an integrated structure and may be formed together as a single piece. As an example, the duct body  226  may be made from a metallic material, although it is possible for the base  222  to be made from a combination of materials—for example, the duct body  226  may be made from an alloy. The duct body  226  may also be made from ceramic or from a combination of a metal and ceramic. In one embodiment, the duct body  226  is made from the same material as the base  222 . Although not limited, manufacturing processes, such as screw-machining and 3D printing may be used to produce the duct body  226 . 
     During assembly (i.e., insertion and securement) of the duct body  226  within the cavity  266  of the receptacle  262 , the rotational alignment surface  366  of the duct body  226  engages the rotational engagement surface  302  of the receptacle  262  in which it is disposed to rotationally align the duct body  226  along the receptacle axis  294  of the receptacle  262 . Further, during assembly of the duct body  226  within the cavity  266  of the receptacle  262 , the axial alignment surface  378  of the duct body  226  engages the axial engagement surface  306  of the receptacle  262  in which it is disposed to axially align the duct body  226  along the receptacle axis  294  of the receptacle  262 . Details regarding an exemplary process involving the assembly of the duct body  226  with the cavity  266  of the receptacle  262  shall be discussed further below in the present disclosure. 
     Referring to  FIGS. 10, 11, and 12 , aspects related to one or more variations in the structure of the duct body  226  and the receptacle  262  shall now be discussed. As shown, each of  FIGS. 10, 11, and 12  relate to a duct body  900  that has certain variations in structure when compared to the structure of the duct body  226 , discussed above. Said variations have been illustrated and disclosed by way of cross-sectional views of the duct body  900  provided in each of the FIGS.  10 ,  11 , and  12 . The duct body  900  may include one or more features and elements as have been discussed for the duct body  226 , and thus one or more of the same or similar reference numerals and nomenclatures shall be applicable to the duct body  900  as have been applied for the duct body  226 . However, several reference numerals used for the duct body  900  may differ from or be in addition to the reference numerals that have been used for the duct body  226  in order to highlight and discuss the differences of the duct body  900  from the duct body  226 . 
     The duct body  900  includes a first straight surface  904  and a second straight surface  908  in place of the first straight surface  392  and the second straight surface  400  of the duct body  226 . As shown, the first straight surface  904  and the second straight surface  908  of the duct body  900  may be flat and planar surfaces unlike the first straight surface  392  and the second straight surface  400  of the duct body  226  that may be curved around the duct axis  326  (see  FIG. 8 ). The first straight surface  904  and the second straight surface  908  may be parallel to each other, as well. Further, the duct body  900  defines a first connecting surface  912 , a second connecting surface  916 , a third connecting surface  920 , and a fourth connecting surface  924 . The first connecting surface  912  extends between the first straight surface  904  and the first duct flat surface  370  of the duct body  900 , the second connecting surface  916  extends between the first straight surface  904  and the second duct flat surface  374  of the duct body  900 , the third connecting surface  920  extends between the second straight surface  908  and the first duct flat surface  370  of the duct body  900 , and the fourth connecting surface  924  extends between the second straight surface  908  and the second duct flat surface  374  of the duct body  900 . Each of the first connecting surface  912 , the second connecting surface  916 , the third connecting surface  920 , and the fourth connecting surface  924 , may be flat surfaces as well. Combined, therefore, the first duct flat surface  370 , the first connecting surface  912 , the first straight surface  904 , the second connecting surface  916 , the second duct flat surface  374 , the fourth connecting surface  924 , the second straight surface  908 , and the third connecting surface  920  may impart an octagonal cross-section to the duct body  900 , as shown. 
       FIGS. 10, 11, and 12  correspondingly also relate to receptacles  928 ,  932 ,  936  that can accommodate the duct body  900 . The receptacles  928 ,  932 ,  936  include variations in their structure when compared to each other and when compared to the structure of the receptacle  262 . Said variations have been illustrated and disclosed by way of cross-sectional views of the receptacles  928 ,  932 ,  936  provided respectively in  FIGS. 10, 11, and 12 . Each of the receptacles  928 ,  932 ,  936  may include one or more features and elements as have been discussed for the receptacle  262 , and thus one or more of the same or similar reference numerals and nomenclatures shall be applicable to each of the receptacles  928 ,  932 ,  936  as have been applied for the receptacle  262 . However, several reference numerals used for the receptacles  928 ,  932 ,  936  may differ from or be in addition to the reference numerals that have been used for the receptacle  262  in order to highlight and discuss the differences of the receptacles  928 ,  932 ,  936  from the receptacle  262 . 
     Referring to  FIG. 10 , the receptacle  928  is shown. The receptacle  928  includes a first arm  940 ′ and a second arm  940 ″. The first arm  940 ′ defines a first arm inner surface  948 ′, a first arm top surface  952 ′, and a first arm exterior surface  956 ′. The first arm inner surface  948 ′ defines a first upright section  960 ′, a first protruded section  964 ′, and a first recessed section  968 ′ defined in between the first upright section  960 ′ and the first protruded section  964 ′. The first upright section  960 ′ is disposed proximal to the floor portion  278  (or the first receptacle flat surface  322 ) of the receptacle  928 , while the first protruded section  964 ′ is disposed distal to the floor portion  278  (or the first receptacle flat surface  322 ) of the receptacle  928  and defines a first top edge  972 ′ of the first arm  940 ′. As exemplarily shown, the first top edge  972 ′ includes a first rounded surface  976 ′ that extends contiguously from the first protruded section  964 ′ and merges contiguously and seamlessly with the first arm top surface  952 ′ of the first arm  940 ′. Further, the first arm exterior surface  956 ′ merges with an external surface  980  of the post portion  274  of the receptacle  928  by way of a first depressed surface  984 ′ that forms an interface between the first arm exterior surface  956 ′ and the external surface  980  of the post portion  274 . 
     Similarly, the second arm  940 ″ defines a second arm inner surface  948 ″, a second arm top surface  952 ″, and a second arm exterior surface  956 ″. The second arm inner surface  948 ″ defines a second upright section  960 ″, a second protruded section  964 ″, and a second recessed section  968 ″ defined in between the second upright section  960 ″ and the second protruded section  964 ″. The second upright section  960 ″ is disposed proximal to the floor portion  278  (or the first receptacle flat surface  322 ) of the receptacle  928 , while the second protruded section  964 ″ is disposed distal to the floor portion  278  (or the first receptacle flat surface  322 ) of the receptacle  928  and defines a second top edge  972 ″ of the second arm  940 ″. As exemplarily shown, the second top edge  972 ″ includes a second rounded surface  976 ″ that extends contiguously from the second protruded section  964 ″ and merges contiguously and seamlessly with the second arm top surface  952 ″ of the second arm  940 ″. Further, the second arm exterior surface  956 ″ merges with the external surface  980  of the post portion  274  of the receptacle  928  by way of a second depressed surface  984 ″ that forms an interface between the second arm exterior surface  956 ″ and the external surface  980  of the post portion  274 . 
     The first arm inner surface  948 ′ and the second arm inner surface  948 ″, in conjunction with the floor portion  278 , defines a cavity  986  of the receptacle  928 . It may be noted that the first protruded section  964 ′ and the second protruded section  964 ″ may be directed towards each other, inwards into the cavity  986 , as shown. The first protruded section  964 ′ and the second protruded section  964 ″ correspondingly define a first protruded edge  990 ′ and a second protruded edge  990 ″, both facing inwards into the cavity  986 , as well. In some embodiments, the first protruded edge  990 ′ and the second protruded edge  990 ′ are filleted edges. In some embodiments, the first protruded edge  990 ′ and the second protruded edge  990 ″ define lengths that may extend along an axis  994  (similar to the receptacle axis  294 ) defined by the cavity  986 . Furthermore, as may be noted, the first groove  320  and the second groove  324  may be missing respectively from between the first arm  940 ′ and the floor portion  278  and between the second arm  940 ″ and the floor portion  278 . Instead, there may be a first rounded continuous surface  998 ′ extending (e.g., with curvature continuity and as an interface) between the first arm  940 ′ and the floor portion  278  and a second rounded continuous surface  998 ″ extending (e.g., with curvature continuity and as an interface) between the second arm  940 ″ and the floor portion  278 . 
     Referring to  FIG. 11 , with regard to the receptacle  932 , all features and references of the receptacle  932  may remain similar to the features and references of the receptacle  928  with the exception that in place of the first protruded edge  990 ′ and the second protruded edge  990 ″, the first protruded section  964 ′ and the second protruded section  964 ″ of the receptacle  932  respectively defines a first flat face  1000 ′ and a second flat face  1000 ″, as shown. The first flat face  1000 ′ and the second flat face  1000 ″ may be directed into the cavity  986  and may define lengths that extend along the axis  994 . 
     Referring to  FIG. 12 , with regard to the receptacle  936 , all features and reference of the receptacle  936  remain similar to the features and references of the receptacle  932  with the exception that in place of the first rounded continuous surface  998 ′ and the second rounded continuous surface  998 ″, a first transition surface  1004 ′ and a second transition surface  1004 ″ are defined that are more pronounced than the first rounded continuous surface  998 ′ and the second rounded continuous surface  998 ″. More particularly, the first transition surface  1004 ′ and the second transition surface  1004 ″ extend into the body of the receptacle  936 , as shown, in a manner to minimize the material at the interface between the arms  940 ′,  940 ″ and the post portion  274  so as to make the arms  940 ′,  940 ″ more flexible and/or deflectable with respect to the floor portion  278  (or the post portion  274 ). The first depressed surface  984 ′ and the second depressed surface  984 ″ may be omitted from the receptacle  936 . 
     Referring to  FIG. 13 , certain further optional embodiments or variations related to the receptacle  262  have been discussed. Said variations have been discussed with reference to a receptacle  1200  that is a variant of the receptacle  262 ″″ (see  FIG. 4 ). All reference numerals applied for the receptacle  262  may be applied to the receptacle  1200 , as well, to illustrate same or like parts. However, the receptacle  1200  may include references to reference numerals that may differ from or be in addition to the reference numerals that have been used for the receptacle  262  in order to highlight and discuss the differences/variations between the receptacle  1200  and the receptacle  262 . 
     The first arm  282 ′ and the second arm  282 ″ of the receptacle  1200  may respectively include a first cutout  1204 ′ and a second cutout  1204 ″, as shown. The first cutout  1204 ′ and the second cutout  1204 ″ may respectively extend from the first top edge  284 ′ and the second top edge  284 ″ of the first arm  282 ′ and the second arm  282 ″ towards the floor portion  278  of the receptacle  1200 . Both the first cutout  1204 ′ and the second cutout  1204 ″ extend through the thicknesses, T 1  and T 2 , defined by the first arm  282 ′ and the second arm  282 ″ to define spaced apart pair of fingers (e.g., a first pair of finger  1208 ′ and a second pair of fingers  1208 ″) on the first arm  282 ′ and the second arm  282 ″, as shown. Further, both the first cutout  1204 ′ and the second cutout  1204 ″ may be U-shaped, although the first cutout  1204 ′ and the second cutout  1204 ″ may be differently shaped, e.g., one or more of the first cutout  1204 ′ and the second cutout  1204 ″ may include a V-shape. By way of the first cutout  1204 ′ and the second cutout  1204 ″, material from the first arm  282 ′ and the second arm  282 ″ may be minimized, flexibility of the first arm  282 ′ and the second arm  282 ″ be increased, and an insertion and assembly of the duct body  226  into the cavity  266  may be further eased. Further, features discussed for the receptacle  1200  may suitably be applied to the receptacles  928 ,  936 ,  938 , as well. 
     INDUSTRIAL APPLICABILITY 
     During assembly of the duct assembly  198  to the flame deck surface  158  of the cylinder head  148 , an operator may bring forth the base  222 , place it against the portion of the flame deck surface  158  defined around the tip portion  206 , and align the base  222  such that the receptacle axis  294  of the receptacle  262  (and the receptacle axes of the remaining receptacles  262 ) fall in line and align with corresponding orifices  214  of the tip portion  206  of the fuel injector  194 . Thereafter, the operator may insert the fasteners  258  through the slots  254  such that the fasteners  258  (e.g., head portions of the fasteners  258 ) may engage the second axial base end  242  of the ring-shaped portion  230  and the fasteners  258  (e.g., shank portions of the fasteners  258 ) may pass through and beyond the first axial base end  238  into corresponding receiving holes (not shown) provided within the flame deck surface  158  of the cylinder head  148 . The fasteners  258  may then be turned into such holes by use of a suitable tool or a driver and be tightly retained to the flame deck surface  158  so as to immovably retain the base  222  with the flame deck surface  158 . As a result, the base  222  is assembled and retained with the flame deck surface  158  such that the receptacle axis  294  of the receptacle  262  (and receptacle axes of the remaining receptacles  262 ) are aligned with corresponding orifices  214  of the fuel injector  194 . Also, once the base  222  is assembled to the flame deck surface  158 , the base axis  234  may lie in line with the longitudinal axis  220  of the fuel injector  194  (see  FIG. 1 ). 
     Referring to  FIGS. 6, 7, and 8 , once the base  222  is mounted to the cylinder head  148 , the operator may bring forth the duct body  226  and may insert the duct body  226  into the cavity  266  of the receptacle  262 . At this point, the operator may cause the rotational alignment surface  366  (or the first duct flat surface  370 ) to face the mouth  288  and the first receptacle flat surface  322  as the duct body  226  is brought towards the mouth  288  for entry into the cavity  266  (see  FIG. 8 ). As the operator attempts to insert the duct body  226  into the cavity  266  of the receptacle  262 , the first straight surface  392  and the second straight surface  400  of the duct body  226  may respectively contact the first top edge  284 ′ and the second top edge  284 ″ of the first arm  282 ′ and the second arm  282 ″, respectively. Thereafter, the operator pushes the duct body  226  further into the cavity  266  of the receptacle  262 . As the first arm  282 ′ and the second arm  282 ″ are deflectable with respect to the floor portion  278 , the force of the engagement between the duct body  226  and the first arm  282 ′ and second arm  282 ″ causes the first arm  282 ′ and the second arm  282 ″ to deflect and move outwards (see direction, B-B′,  FIG. 8 ), thus increasing the distance, D 1 , defined between the first top edge  284 ′ and the second top edge  284 ″, and in turn expanding and opening up the mouth  288  of the cavity  266  defined between the first top edge  284 ′ and the second top edge  284 ″. 
     As the operator continues to push the duct body  226  into the cavity  266 , the first arm  282 ′ and the second arm  282 ″ may further deflect and the first top edge  284 ′ and the second top edge  284 ″ may move further away from each other and attain a distance equivalent to the distance, D 2 . As soon as the distance between the first top edge  284 ′ and the second top edge  284 ″ equals (or minimally exceeds) the distance, D 2 , the duct body  226  may slide into the cavity  266  and be snapped into the cavity  266  of the receptacle  262 . Given that the first duct flat surface  370  were facing the first receptacle flat surface  322  during entry, as soon as the duct body  226  is snapped and received into the cavity  266  of the receptacle  262 , the first duct flat surface  370  falls into abutment with the first receptacle flat surface  322 , thereby engaging the rotational alignment surface  366  of the duct body  226  with the rotational engagement surface  302  of the receptacle  262  and rotationally aligning the duct body  226  along the receptacle axis  294  of the receptacle  262 . In that manner, the duct body  226  attains an assembled state with the receptacle  262  (see  FIG. 9 ). 
     It may be noted that said manner of abutment of the first duct flat surface  370  with the first receptacle flat surface  322  enables an error free assembly of the duct body  226  within the cavity  266  of the receptacle  262 . Once the duct body  226  is fully accommodated within the cavity  266 , the duct axis  326  may fall in line with the receptacle axis  294 . Further, the first top edge  284 ′ and the second top edge  284 ″ may return to their initial positions (see direction, C-C′,  FIG. 8 ) to define the distance, D 1 , therebetween, thus urging the first duct flat surface  370  to remain abutted with the first receptacle flat surface  322 . 
     Moreover, given that the length defined by the first straight surface  392  along the duct axis  326  may be equal to the distance, E 1 , and a length defined by the second straight surface  400  along the duct axis  326  may be equal to the distance, E 2 , in such accommodation of the duct body  226  within the cavity  266  of the receptacle  262 , the ridges  382  come into contact with the first lateral side edge  314 ′ and the second lateral side edge  318 ′ of the first arm  282 ′ and engages and entraps the first arm  282 ′ of the U-shaped portion  270  therebetween. Similarly, the ridges  394  come into contact with the first lateral side edge  314 ″ and the second lateral side edge  318 ″ of the second arm  282 ″ and engages and entraps the second arm  282 ″ of the U-shaped portion  270  therebetween. In so doing, the axial alignment surface  378  of the duct body  226  engages the axial engagement surface  306  of the receptacle  262  to axially align the duct body  226  along the receptacle axis  294  of the receptacle  262 . 
     In an assembly of the duct body  226  within the cavity  266  of the receptacle  262 , the first arm  282 ′ and the second arm  282 ″ resiliently engage a portion (e.g., the straight part  352 ) of the duct body  226  and secure the duct body  226  therebetween. It may also be noted that engagement of the axial alignment surface  378  with the axial engagement surface  306  further includes at least a partial capture of the first recessed portion  390  and the second recessed portion  404  of the duct body  226  into the U-shaped portion  270  of the receptacle  262 . Further, it is possible for the duct body  226  to be assembled to the base  222  first before the base  222  is assembled to the flame deck surface  158  of the cylinder head  148 . 
     As part of the assembly of the duct body  226  to the receptacle  262 , the engagement of the rotational alignment surface  366  with the rotational engagement surface  302  allows the duct body  226  to be captured appropriately and correctly into the cavity  266 . The first arm  282 ′ and the second arm  282 ″ urges the first duct flat surface  370  to remain abutted with the first receptacle flat surface  322 , preventing rotation of the duct body  226  with respect to the receptacle  262  and from loosening out from the receptacle  262 . Moreover, the engagement of the axial alignment surface  378  with the axial engagement surface  306  prevents axial misplacement of the duct body  226  with respect to the receptacle  262  along the receptacle axis  294  defined by the receptacle  262 . In effect, owing to the rotational engagement surface  302  and the axial engagement surface  306  of the base  222  and the rotational alignment surface  366  and the axial alignment surface  378  of the duct body  226 , the duct body  226  is appropriately and correctly located and oriented with respect to the receptacle  262  and thus the base  222 , during assembly. An assembly of the duct body  226  with the receptacle  1200  may be understood based on the manner in which the assembly of the duct body  226  to the receptacle  262  has been discussed above. 
     Further, an assembly of the duct body  900  with the receptacles  928 ,  932 ,  936  may also be understood based on the manner in which the assembly of the duct body  226  to the receptacle  262  has been discussed above. During assembly of the duct body  900  with the receptacle  928 , for example, the first connecting surface  912  and the third connecting surface  920  may respectively come into contact with the first top edge  972 ′ and the second top edge  972 ″. As the operator continues to push the duct body  900  into the cavity  986 , the first arm  940 ′ and the second arm  940 ″ may flex and expand (e.g., see direction, B-B′, applied for the receptacle  262 ,  FIG. 8 ). The first depressed surface  984 ′ and the second depressed surface  984 ″ may ease such flexure of the first arm  940 ′ and the second arm  940 ″, to facilitate an entry of the duct body  900  into the cavity  986 . Simultaneously, or in consequence, the first recessed section  968 ′ and the second recessed section  968 ″ may respectively enable the first protruded section  964 ′ and the second protruded section  964 ″ to flex as well (e.g., inwards into the cavity  986 ) relative to the first upright section  960 ′ and the second upright section  960 ″, helping the duct body  900  to be inserted into the cavity  986 . 
     Once the duct body  900  is snapped and received into the cavity  986 , an assembled state of the duct body  900  with the receptacle  928  is attained (see view illustrated in  FIG. 10 ). In the assembled state, the first protruded edge  990 ′ of the receptacle  928  contacts the second connecting surface  916  of the duct body  900  and the second protruded edge  990 ″ of the receptacle  928  contacts the fourth connecting surface  924  of the duct body  900  to secure the duct body  900  within the cavity  986  of the receptacle  928 . In some embodiments, the first protruded edge  990 ′ of the receptacle  928  and the second protruded edge  990 ″ of the receptacle  928  respectively define a line of contact (e.g., along the axis  994 ) with the second connecting surface  916  of the duct body  900  and the fourth connecting surface  924  of the duct body  900 . 
     An assembly of the duct body  900  into the receptacles  932 ,  936  may remain similar to the manner of assembly of the duct body  900  into the receptacle  928 . In the assembled state of the duct body  900  into the receptacles  932 ,  936  the first flat face  1000 ′ of the receptacles  932 ,  936  contacts the second connecting surface  916  of the duct body  900  and the second flat face  1000 ″ of the receptacles  932 ,  936  contacts the fourth connecting surface  924  of the duct body  900 . In some embodiments, the first flat face  1000 ′ and the second flat face  1000 ″ respectively define a surface of contact or a plane of contact with the second connecting surface  916  and the fourth connecting surface  924 . 
     A contact area defined by the first protruded edge  990 ′ and the second protruded edge  990 ″ or a contact area defined by the first flat face  1000 ′ and the second flat face  1000 ″ with the second connecting surface  916  and the fourth connecting surface  924  may be lesser when compared to a contact area defined between the duct body  226  and the arms  282 ′,  282 ″ of the receptacle  262 . In so doing, a force applied by the arms  940 ′,  940 ″ per unit area over the duct body  900  may be greater when compared to the force applied by the arms  282 ′,  282 ″ on the duct body  226 , enabling the arms  940 ′,  940 ″ to urge the first duct flat surface  370  of the duct body  900  to remain abutted with the first receptacle flat surface  322  with greater effectiveness. 
     It may also be noted that in the assembled state of the duct body  900  with the receptacles  928 ,  932 ,  936 , the first straight surface  904  may define a first clearance, FC, with the first upright section  960 ′ and the second straight surface  908  may define a second clearance, SC, with the second upright section  960 ″, thereby reducing the contact area between the arms  940 ′,  940 ″ and the duct body  900 . Also, by providing the first straight surface  904  and the second straight surface  908 , the duct body  900  may be inserted in any orientation, while still maintaining the angular alignment once secured within the receptacle  928 ,  932 ,  936 . 
     The duct bodies  226  and the receptacle  262  (or the base  222  that includes the receptacle  262 ) being separate entities, enables the duct bodies  226  and the base  222  to be manufactured separately, which allows desired (and complex) duct geometries (e.g., with a higher or a lower angle, A, a smaller dimension of the duct  330 , the 180 degrees rounded profile of the arcuate inlet surface  358 , or a higher number of duct bodies  226 ) to be formed, making an associated manufacturing process less complex and less tedious. Moreover, the entire duct assembly  198  need not be removed if only one or few duct bodies  226  needed service and/or repairs. In some cases, coupling techniques such as welding, brazing, or gluing, may be applied to retain the first duct flat surface  370  with the first receptacle flat surface  322 , or such techniques may be applied between other portions of the duct body  226  and the receptacle  262 , to immovably couple and house the duct body  226  within the cavity  266  of the receptacle  262 . 
     Similar discussions and applicability may be contemplated for the duct body  900  and the receptacles  928 ,  932 ,  936 ,  1200  (and/or their corresponding bases that include the receptacles  928 ,  932 ,  936 ,  1200 ), as well. Further, it may be noted that one or more of the features associated with the duct body  226  and the receptacle  262  and/or one or more of the features associated with the variants of the duct body  226  (i.e., the duct body  900 ) and the receptacle (i.e., the receptacles  928 ,  932 ,  936 ,  1200 ), as have been discussed in the present disclosure, may be applied in any combination with one another. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the method and/or system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and/or system disclosed herein. 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 equivalent.