Patent Publication Number: US-9410520-B2

Title: Internal combustion engine including an injector combustion seal positioned between a fuel injector and an engine body

Description:
TECHNICAL FIELD 
     This disclosure relates to fuel injector seal assemblies for internal combustion engines. 
     BACKGROUND 
     An internal combustion engine with a fuel injector may require a combustion seal to keep combustion gases in a combustion chamber of the internal combustion engine from flowing into a passage surrounding the fuel injector. One challenge with such seals is that they may be inefficient in transporting or transferring heat away from a nozzle housing of the fuel injector, or if such seals transport heat away from a distal end of a nozzle element housing, the seals may have insufficient strength to resist yielding, which may ultimately permit leaks. 
     SUMMARY 
     This disclosure provides an internal combustion engine including a fuel injector assembly for mounting in an engine cylinder head, comprising an engine cylinder head sealing surface, a fuel injector body, and an injector seal assembly. The fuel injector body includes a longitudinal axis, a nozzle element housing, and a nozzle retainer. The injector seal assembly is positioned between the fuel injector body and the engine cylinder head, and the injector seal assembly includes a seal component formed of a first material, the seal component positioned in a space formed longitudinally between the fuel injector body and the engine cylinder head sealing surface for receiving a fuel injector clamp force, and a thermally conductive component formed of a second material different than the first material, the second material having a higher thermal conductivity than the first material, and the thermally conductive component positioned radially between the nozzle element housing and the seal component to transfer heat from the nozzle element housing to the seal component. 
     This disclosure also provides an internal combustion engine, comprising a mounting bore, a fuel injector positioned in the mounting bore, and an injector seal assembly. The mounting bore has a longitudinal axis formed in a portion of the engine and includes a sealing surface formed at a first angle with respect to the longitudinal axis. The fuel injector is positioned in the mounting bore and the fuel injector includes an injector body having a nozzle housing. The injector seal assembly includes a sealing ring and a heat transfer sleeve. The sealing ring is positioned longitudinally between the injector body and the sealing surface to create a first fluid seal between the sealing ring and the sealing surface. The heat transfer sleeve includes a heat transfer sleeve first end, a heat transfer sleeve second end, a heat transfer sleeve inner surface, and a heat transfer sleeve outer surface. The heat transfer sleeve is sized and dimensioned to be positionable in the mounting bore adjacent the nozzle housing. The heat transfer sleeve inner surface is dimensioned to exert a radial force inwardly on the nozzle housing at the heat transfer sleeve second end and the heat transfer sleeve outer surface is dimensioned to exert a radial force outwardly on the sealing ring at the heat transfer sleeve first end. 
     This disclosure also provides an internal combustion engine comprising an engine body, a fuel injector, a spacer component, and a thermally conductive component. The engine body includes a combustion chamber and a mounting bore. The fuel injector is positioned in the mounting bore and includes a longitudinal axis and a distal end. The spacer component is positioned longitudinally between the fuel injector and the engine body at a spaced longitudinal distance from the distal end. The thermally conductive component is in contact with the distal end and with the spacer component and is positioned a spaced radial distance from the engine body and a spaced radial distance from the fuel injector in a region extending between the distal end and the spacer component. 
     Advantages and features of the embodiments of this disclosure will become more apparent from the following detailed description of exemplary embodiments when viewed in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of an injector seal assembly in accordance with a first exemplary embodiment of the present disclosure inserted into position in an engine mounting bore. 
         FIG. 2  is a perspective view of the injector seal assembly of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of an injector seal assembly in accordance with a second exemplary embodiment of the present disclosure inserted into position in an engine mounting bore. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of an injector seal assembly, generally indicated at  10  in  FIGS. 1 and 2 , includes a seal component, sealing ring, or spacer component  12  formed of a first material, and a heat transfer sleeve, heat transfer inner sleeve, or thermally conductive component  14  that is formed of a second material that is different from the first material, for positioning in a fuel injector mounting bore  16  formed in a portion, e.g., cylinder head  18 , of an engine body  19  of an internal combustion engine. While sealing ring  12  and thermally conductive component  14  are formed as distinct or separate components, in the exemplary embodiment they are connected to each other to form injector seal assembly  10 , described in more detail hereinbelow. Cylinder head  18  includes an interior surface  20  that forms fuel injector mounting bore  16 . The internal combustion engine also includes a fuel injector  22 , which includes a peripheral exterior surface  24 , positioned in fuel injector mounting bore  16 . Interior surface  20  of fuel injector mounting bore  16  and exterior surface  24  of fuel injector  22  forms an annular gap or passage  26  that extends radially between fuel injector  22  and cylinder head  18 . Engine body  19 , which includes cylinder head  18 , also includes an engine block  40  to which cylinder head  18  is attached. Engine block  40  includes one or more cylinders  42 , and a piston  44  positioned for reciprocal movement in each cylinder  42 . During longitudinal movement of piston  44  toward fuel injector  22 , fuel injector  22  injects fuel into a combustion chamber  46  formed by the portion of cylinder  42  that extends from piston  44  to cylinder head  18 . 
     The process of combustion needs to be separated from annular gap or passage  26  or damage to fuel injector  22 , cylinder head  18 , and other components of the internal combustion engine can occur. While it is known to position a seal between a fuel injector and a cylinder head, such seals have an array of challenges. For example, the seal must be able to carry a fuel injector clamp load to maintain structural integrity when clamped between fuel injector  22  and cylinder head  18 . While injector seal assembly  10  achieves the core benefit of combustion sealing, it beneficially combines combustion sealing with an enhanced ability to conduct, transfer, or wick heat away from the distal end of fuel injector  22  to maintain the reliability of fuel injector  22 . Injector seal assembly  10  addresses these challenges by fabricating sealing ring  12  of a metal able to withstand the fuel injector clamp loads transmitted through fuel injector  22  into sealing ring  12  and then into cylinder head  18 , and by fabricating separate heat transfer sleeve  14  of a metal having a higher thermal conductivity than the material of sealing ring  12 . Additionally, the contact between sealing ring  12 , heat transfer sleeve  14 , fuel injector  22 , and cylinder head  18  is optimized to transfer heat from the distal end of fuel injector  22  upwardly to a cooler portion of fuel injector  22 , providing a thermal path for heat from the distal end of fuel injector  22 . 
     Throughout this specification, inwardly, distal, and near are longitudinally in the direction of combustion chamber  46 . Outwardly, proximate, and far are longitudinally away from the direction of combustion chamber  46 . 
     Fuel injector  22  includes a plurality of components, including an injector body  28  in which is positioned a needle or nozzle valve element  30 . Fuel injector  22  includes other elements, including an actuator (not shown). Injector body  28  includes a nozzle element housing  32  and a housing retainer  36  that attaches nozzle element housing  32  to fuel injector  22 . Injector body  28  also includes a nozzle element cavity  38  in which nozzle valve element  30  is positioned for reciprocal movement along a fuel injector longitudinal axis  60 . Nozzle element housing  32  includes a nozzle housing diameter. 
     Annular gap or passage  26  is simply, easily and reliably sealed from combustion chamber  46  to isolate annular gap or passage  26  from combustion chamber  46  by insertion of injector seal assembly  10  between fuel injector  22  and a portion of the internal combustion engine, e.g., cylinder head  18 . More specifically, sealing ring  12  is positioned longitudinally between injector body  28  and a sealing surface formed in fuel injector mounting bore  16 . Injector seal assembly  10  provides a metal to metal combustion seal with contact pressures high enough to yield sealing ring  12  into sealing contact against interior surface  20  of injector mounting bore  16 , and then maintain that contact pressure with the force from the fuel injector  22  mounting or securement system (not shown). That is, the injector clamping or securing load, for securing fuel injector  22  in mounting bore  16 , is relied upon to apply a sealing force to sealing ring  12 . In an exemplary embodiment, injector mounting bore  16  includes a sealing surface  80  positioned at an angle to longitudinal axis  60 , thus providing a conical sealing surface, and sealing ring  12  includes sealing ring angled surface  82  that contacts bore angled surface  80  when sealing ring  12  is positioned longitudinally between injector body  28  and sealing surface  80  in injector mounting bore  16 . The contact between sealing ring angled surface  82  and sealing surface  80  forms a fluid seal. In an exemplary embodiment, bore angled surface  80  is at a full angle of about 90 degrees, and sealing ring angled surface  82  is at a full angle of about 87.25 degrees, which is an angle of about 43.625 degrees with respect to longitudinal axis  60 . The clamp load that holds fuel injector  22  in injection mounting bore  16  transfers load through a load path that includes an annular line of contact  84  between bore angled surface  80  and sealing ring angled surface  82 , forming a fluid seal between sealing ring  12  and engine body  19 . 
     In addition to forming a fluid seal between sealing ring  12  and engine body  19 , sealing ring  12  forms a fluid seal with injector body  28 . More specifically, sealing ring  12  includes a sealing ring proximate end surface  76  and injector body  28  includes an injector body surface  86 , and the clamp load that forms a fluid seal between sealing ring  12  and engine body  19  also forms a load path through sealing ring proximate end surface  76  and injector body surface  86  to create a fluid seal between sealing ring proximate end surface  76  and injector body surface  86 . 
     Sealing ring  12  is sized, dimensioned, and formed of an appropriate material such that sealing ring  12  retains its structural integrity under the clamp load from the fuel injector  22  mounting or securement system. Sealing ring  12  is generally circular in shape and includes a longitudinally extending central ring passage  48  having a first ring diameter  52  formed by an annular lower ring wall portion  50 , a second, larger ring diameter  54  formed by an annular upper ring wall portion  56 , and a step or transition portion  58  positioned between lower ring wall portion  50  and upper ring wall portion  56 . Upper ring wall portion  56  has a longitudinal length  72 . In the exemplary embodiment, sealing ring  12  is formed of a single unitary piece. While sealing ring  12  may be formed of multiple pieces, a single piece is easier to form and assemble as opposed to two or more pieces. In an exemplary embodiment, sealing ring  12  is formed of a stainless steel material, which may be an SAE 303 stainless steel. In addition to the other benefits provided by sealing ring  12 , the material of sealing ring  12  provides a thermal barrier to the combustion heat from combustion chamber  46 . 
     Sealing ring  12  includes ring proximate end surface  76  and a sealing ring angled surface  82 . As described hereinabove, proximate end surface  76  is sized and dimensioned to form a fluid seal with fuel injector body  28 . In an exemplary embodiment, proximate end surface  76  is a flat, planar surface that abuts or contacts a distal end of housing retainer  36 , which has a flat, planar injector body surface  86  that mates with proximate end surface  76 . 
     Heat transfer sleeve  14  is sized, dimensioned, and formed of an appropriate material to yield when forced into an interference fit with another component, such as nozzle element housing  32  or sealing ring  12 . Heat transfer sleeve  14  is a component that is fabricated distinctly or formed separately from sealing ring  12  of a material that is different from the material of sealing ring  12 . The purpose of the two different materials is to beneficially combine a material having sufficient a structural or load bearing strength to receive the significant clamp loads required to secure fuel injector  22  in cylinder head  18  with an enhanced thermal conductivity to transport, transfer, or wick heat from a distal end of nozzle element housing  32  toward an upper portion of fuel injector  22  that is cooler than the distal end of nozzle element housing  32 . The benefit to this heat transfer is that it reduces the temperature in the distal end of nozzle element housing  32 , reducing nozzle tip temperatures and reducing the degradation of fuel, which can cause deposits on nozzle element housing  32 . These deposits can contribute to erratic spray patters from fuel injector  22  as well as drift in the quantity of fuel injected. Heat transfer sleeve  14  includes a distal end  62 , a proximate end or head portion  64 , and a longitudinally extending portion  66  that connects distal end  62  to proximate end  64  to position proximate end  64  a spaced longitudinal distance from distal end  62 . In the exemplary embodiment, heat transfer sleeve  14  is formed of a single unitary piece. While heat transfer sleeve  14  may be formed of multiple pieces, a single piece is easier to form and assemble as opposed to two or more pieces. 
     Distal end  62  has an inner surface  63  at a distal end diameter  68  that is smaller than the nozzle housing diameter. During assembly of fuel injector  22 , when heat transfer sleeve  14  is positioned on nozzle element housing  32 , inner surface  63  is adjacent to, mates with, abuts, or faces the peripheral outer surface of nozzle element housing  32  and heat transfer sleeve  14  achieves an interference fit with nozzle element housing  32  because distal end diameter  68  is smaller than the nozzle housing diameter. Furthermore, because heat transfer sleeve  14  is fabricated from a material that is softer or weaker than the material of nozzle element housing  32 , heat transfer sleeve  14  yields or flexes during assembly rather than causing significant distortion or yielding of nozzle element housing  32 . In the exemplary embodiment, heat transfer sleeve  14  is formed of a copper material, which in the exemplary embodiment is either UNS C15100 or UNS C15000 and includes an H01 temper. It should be understood that other materials having suitable thermal conductivity and suitable yield strength may also be used. 
     Proximate end  64  includes an exterior proximate end diameter that is larger than first ring diameter  52  and may be larger than second ring diameter  54 . Proximate end  64  further includes an annular peripheral or outer surface  70 . If the exterior proximate end diameter of proximate end  64  is larger than second ring diameter  54 , then when heat transfer sleeve  14  is inserted into sealing ring  12  from a proximate end of sealing ring  12 , peripheral surface  70  is adjacent to, faces, abuts, or mates with upper ring wall portion  56  and forms an interference or press fit with upper ring wall portion  56 . Proximate end  64  includes a longitudinal length that is less than longitudinal length  72  of upper ring wall portion  56  so that when heat transfer sleeve  14  is inserted into sealing ring  12  and injector seal assembly  10  is positioned between fuel injector  22  and cylinder head  18 , heat transfer sleeve  14  is able to move longitudinally because of a gap  74  that may be positioned longitudinally between injector body  28  and the proximate end of heat transfer sleeve  14 , or may be positioned longitudinally between a distal end of proximate end  64  and step or transition portion  58 , or gap  74  may be in both locations. The purpose of gap  74  is to prevent the significant clamp loads transmitted from injector body  28  through sealing ring  12  into cylinder head  18  from being transmitted through heat transfer sleeve  14 . It should also be apparent from the description of proximate end  64  and length  72  that head portion  64  is captured between injector body  28  and step portion  58 . 
     Longitudinally extending portion  66  connects distal end  62  with proximate end  64 . Longitudinally extending portion  66  is a spaced radial distance from engine body  19 , e.g., cylinder head  18 , and a spaced radial distance from fuel injector  22 , e.g., nozzle element housing  32 . One purpose for spacing longitudinally extending portion  66  from fuel injector  22  is to reduce the assembly force required to press heat transfer sleeve  14  onto fuel injector  22 , which might otherwise cause heat transfer sleeve  14  to distort under the force of assembly or installation. Longitudinally extending portion  66  may have a diameter greater than first ring diameter  52  where the outer surface of longitudinally extending portion  66  is adjacent to, faces, abuts, or mates with lower ring wall portion  50 , which would thus cause longitudinally extending portion  66  to be a press or interference fit with lower ring wall portion  50 . Heat transfer sleeve  14  may be an interference or press fit with lower ring wall portion  50 , with upper ring wall portion  56 , or with both lower ring wall portion  50  and upper ring wall portion  56 . One benefit to using one component, i.e., sealing ring  12 , as a seal and to receive the clamping forces that hold fuel injector  22  into cylinder head  18 , and a second component, i.e., heat transfer sleeve  14  in a location extending from a distal end of nozzle element housing  32  to sealing ring  12 , is that injector seal assembly  10  achieves the core benefit of combustion sealing combined with a heat transfer function. The heat is received by heat transfer sleeve  14  at the distal end of nozzle element housing  32  and the heat is readily conducted from heat transfer sleeve  14  into sealing ring  12 , where the heat may then flow into fuel injector body  28 , e.g., housing retainer  36 . Another benefit to this contact is that it is easier to assemble sealing ring  12  and separate heat transfer sleeve  14  as an assembly prior to attaching sealing ring  12  and heat transfer sleeve  14  to fuel injector  22  rather than attaching each component to fuel injector  22  individually. 
     Referring now to  FIG. 3 , a second exemplary embodiment of the present disclosure is shown. Elements that are the same as the first embodiment are numbered the same as the first embodiment, and are described in this embodiment only for the sake of clarity. A second exemplary embodiment of an injector seal assembly, generally indicated at  110  in  FIG. 3 , includes seal component, sealing ring, or spacer component  12 , and a heat transfer sleeve, heat transfer inner sleeve, or thermally conductive component  114 , for positioning in fuel injector mounting bore  16  formed in a portion, e.g., cylinder head  18 , of engine body  19  of an internal combustion engine. Cylinder head  18  includes interior surface  20  that forms fuel injector mounting bore  16 . The internal combustion engine also includes fuel injector  22 , which includes peripheral exterior surface  24 , positioned in fuel injector mounting bore  16 . Interior surface  20  of fuel injector mounting bore  16  and exterior surface  24  of fuel injector  22  forms annular gap or passage  26  that extends radially between fuel injector  22  and cylinder head  18 . 
     Fuel injector  22  includes a plurality of components, including injector body  28  in which is positioned needle or nozzle valve element  30 . Injector body  28  includes nozzle element housing  32  and housing retainer  36  that attaches nozzle element housing  32  to fuel injector  22 . Injector body  28  also includes nozzle element cavity  38  in which nozzle valve element  30  is positioned for reciprocal movement along a fuel injector longitudinal axis  160 . Nozzle element housing  32  includes a nozzle housing diameter. 
     Annular gap or passage  26  is simply, easily and reliably sealed from combustion chamber  46  to isolate annular gap or passage  26  from combustion chamber  46  by insertion of injector seal assembly of  110  between fuel injector  22  and a portion of the internal combustion engine, e.g., cylinder head  18 . Injector seal assembly  110  provides a metal to metal combustion seal with contact pressures high enough to yield sealing ring  12  into sealing contact against interior surface  20  of injector mounting bore  16 , and then maintain that contact pressure with the force from the fuel injector  22  mounting or securement system (not shown). That is, the injector clamping or securing load, for securing fuel injector  22  in mounting bore  16 , is relied upon to apply a sealing force to sealing ring  12 . In an exemplary embodiment, injector mounting bore  16  includes angled surface  80  and sealing ring  12  includes sealing ring angled surface  82  that contacts bore angled surface  80  when injector seal assembly  110  is positioned in injector mounting bore  16 . In an exemplary embodiment, bore angled surface  80  is at a full angle of about 90 degrees, and sealing ring angled surface  82  is at a full angle of about 87.25 degrees. The clamp load that holds fuel injector  22  in injection mounting bore  16  causes annular line of contact  84  between bore angled surface  80  and sealing ring angled surface  82 , forming a fluid seal between sealing ring  12  and engine body  19 . Sealing ring  12  is configured as previously described. 
     Heat transfer sleeve  114  is sized, dimensioned, and formed of an appropriate material to yield when forced into an interference fit with another component, such as nozzle element housing  32  or sealing ring  12 . Heat transfer sleeve  114  includes a distal end  162 , a proximate end  164 , and a longitudinally extending portion  166  that connects distal end  162  to proximate end  164 . 
     Distal end  162  has a distal end diameter  168  that is smaller than the nozzle housing diameter and an inner surface  163 . During assembly of fuel injector  22 , when heat transfer sleeve  114  is positioned on nozzle element housing  32 , heat transfer sleeve  114  achieves an interference fit with nozzle element housing  32  because inner surface  163  is adjacent to, mates with, abuts, or faces the peripheral outer surface of nozzle element housing  32  and because distal end diameter  168  is smaller than the nozzle housing diameter. Furthermore, because heat transfer sleeve  114  is formed from a material that is softer or weaker than the material of nozzle element housing  32 , heat transfer sleeve  114  yields or flexes during assembly rather than causing significant distortion or yielding of nozzle element housing  32 . In the exemplary embodiment, heat transfer sleeve  114  is formed of a copper material, which in the exemplary embodiment is either UNS C15100 or UNS C15000 and includes an H01 temper. It should be understood that other materials having suitable thermal conductivity and suitable yield strength may also be used. 
     Proximate end  164  includes an exterior proximate end diameter that is larger than first ring diameter  52  and may be larger than second ring diameter  54 . Proximate end  164  further includes annular peripheral or outer surface  70 . If the exterior proximate end diameter of proximate end  164  is larger than second ring diameter  54 , then when heat transfer sleeve  114  is inserted into sealing ring  12 , peripheral surface  70  forms an interference or press fit with upper ring wall portion  56 . Proximate end  164  includes a longitudinal length that is less than longitudinal length  72  of upper ring wall portion  56  so that when heat transfer sleeve  114  is inserted into sealing ring  12  and injector seal assembly  110  is positioned between fuel injector  22  and cylinder head  18 , heat transfer sleeve  114  is able to move longitudinally because of gap  74  that may be positioned longitudinally between injector body  28  and the proximate end of heat transfer sleeve  114 , or may be positioned longitudinally between a distal end of proximate end  64  and transition portion  58 , or gap  74  may be in both locations. The purpose of gap  74  has been described hereinabove. 
     Longitudinally extending portion  166  connects distal end  162  with proximate end  164 . Longitudinally extending portion  166  is a spaced distance from engine body  19 , e.g., cylinder head  18 , and a spaced distance from fuel injector  22 , e.g., nozzle element housing  32 . Longitudinally extending portion  166  may have a diameter greater than first ring diameter  52  where longitudinally extending portion  166  is adjacent to, faces, abuts, or mates with lower ring wall portion  50 , which would thus cause longitudinally extending portion  166  to be a press or interference fit with lower ring wall portion  50 . Heat transfer sleeve  114  may be an interference or press fit with lower ring wall portion  50 , with upper ring wall portion  56 , or with both lower ring wall portion  50  and upper ring wall portion  56 . One benefit to the contact between heat transfer sleeve  114  and sealing ring  12  is that heat is readily conducted from heat transfer sleeve  114  into sealing ring  12 , where the heat may then flow into fuel injector body  28 . A benefit to the press fit contact is that it is easier to assemble sealing ring  12  to separate heat transfer sleeve  114  rather than positioning heat transfer sleeve  114  on nozzle element housing  32  and then attaching sealing ring  12  to heat transfer sleeve  114 . 
     Proximate end  164  also includes an interior diameter  178 , which in this embodiment is smaller than the outside diameter of nozzle element housing  32 , and an annular inner surface  179 . The result of this dimension is that inner surface  179  of proximate end  164  of heat transfer sleeve  114  is a press or interference fit with nozzle element housing  32 . Thus, heat transfer sleeve  114  is a press or interference fit with nozzle element housing  32  at distal end  162  and at proximate end  164 , and a press or interference fit with sealing ring  12 , as described in the first embodiment. The choice of locations for interference fits will depend on the need to secure heat transfer sleeve  114  with respect to nozzle element housing  32  and sealing ring  12 . 
     While various embodiments of the disclosure have been shown and described, it is understood that these embodiments are not limited thereto. The embodiments may be changed, modified and further applied by those skilled in the art. Therefore, these embodiments are not limited to the detail shown and described previously, but also include all such changes and modifications.