Abstract:
An air heater for heating air entering a combustion chamber of an internal combustion engine is disclosed. The air heater includes a heating element having a substantially planar portion and a flange portion. The flange portion is positioned at an angle to the planar portion. The planar portion is positioned within an air flow at an upstream location relative to the flange portion. A structure is operable to position the heating element in communication with the air entering the combustion chamber of the engine. In addition, a thermal expansion joint for interconnecting a heating element and a frame is disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/381,207 filed on May 2, 2006, which application claims the benefit of U.S. Provisional Application No. 60/679,097 filed on May 9, 2005. The disclosures of the above applications are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present disclosure generally relates to air heaters for internal combustion engines. More particularly, the present disclosure relates to an air heater including a heating element having a flange or multiple flanges extending along its length. Furthermore, the present disclosure relates to a thermal expansion joint for interconnecting a plurality of stacked heating elements. 
         [0003]    Air heaters may be used in automotive applications to heat air prior to entering a combustion chamber of an internal combustion engine. Typical air heaters include heating elements formed from substantially planar ribbons of metal that emit heat while an electrical current is passed therethrough. Because packaging an engine and its associated accessories within an engine compartment is becoming a great challenge, intake tube, intake manifold and internal combustion engine head geometry often times require the intake air flowing from outside of the vehicle to turn ninety degrees prior to entering the combustion chambers. Many times, the air intake heater is positioned at a location at or near the ninety degree bend. Accordingly, a need in the art exists to not only heat the air prior to entering the combustion chamber but also to redirect the air to optimize the flow of the air charge as it passes through the intake components and enters the combustion chambers. 
         [0004]    Furthermore, it is common for the heating elements of the air heater to be energized for a period of time until the engine warms up and subsequently not energized for a relatively long period of time. This thermal cycling causes the heating elements to expand and contract amounts corresponding to the heating element&#39;s coefficient of thermal expansion. Depending on the manner in which the heating elements are mounted within the air heater, undesirable stresses may be imparted to the heating element during the thermal cycling. Accordingly, it is desirable to provide a thermal expansion joint which properly supports and mounts the heating elements within the air heater without inducing undesirable stress. 
       SUMMARY 
       [0005]    The present disclosure provides an air heater for heating air entering a combustion chamber of an internal combustion engine. The air heater includes a heating element having a substantially planar portion and a flange portion. The flange portion is positioned at an angle to the planar portion. The planar portion is positioned within an air flow at an upstream location relative to the flange portion. A structure is operable to position the heating element in communication with the air entering the combustion chamber of the engine. 
         [0006]    Furthermore, in another form, an air heater for heating air entering a combustion chamber of an internal combustion engine is described. The air heater includes a frame having an aperture extending therethrough. A heating element having first and second ends is positioned in communication with the aperture. A retainer couples the first end of the heating element to the frame. The retainer is operable to move relative to the frame to allow the heating element to thermally expand and contract during operation of the heater. It should be understood that the detailed description and specific examples, while describing the certain embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
     
    
     
       DRAWINGS 
         [0007]    The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0008]      FIG. 1  is an exploded perspective view of an exemplary intake assembly constructed in accordance with the teachings of the present disclosure; 
           [0009]      FIG. 2  is a partial exploded perspective view of the intake assembly of  FIG. 1 ; 
           [0010]      FIG. 3  depicts a heating element of the present disclosure in a number of perspective view; 
           [0011]      FIG. 4  is a partial fragmentary exploded perspective view of an alternate embodiment intake assembly; 
           [0012]      FIG. 5  depicts partial fragmentary perspective view of another alternate embodiment intake assembly; 
           [0013]      FIG. 6  is a partial fragmentary cross-sectional view taken through an exemplary thermal joint of the present disclosure; 
           [0014]      FIG. 7  is a fragmentary sectional perspective view of the intake assembly of the present disclosure; 
           [0015]      FIG. 8  is a perspective view of another alternate embodiment intake assembly; 
           [0016]      FIG. 9  depicts an assembled view and an exploded perspective view of an alternate embodiment shoulder bolt; and 
           [0017]      FIG. 10  depicts an assembled perspective and an exploded perspective view of an alternate embodiment shoulder bolt. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]    The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. 
         [0019]      FIGS. 1-3  relate to a first embodiment intake assembly  4  configured to mount to a head (not shown) of an internal combustion engine. An intake tube, also not shown, is typically mounted to a side of intake assembly  4  opposite the head. Effectively, intake assembly  4  is sandwiched between the intake tube and the head of the engine. Intake assembly  4  includes a cover plate  5  having a first through aperture  6  positioned adjacent to a second through aperture  7 . A first heater subassembly  8  is positioned in aperture  6  and coupled to cover plate  5 . A second heater subassembly  9  is coupled to cover plate  5  and positioned within aperture  7 . Both heater subassemblies  8  and  9  are positioned within an air passageway for supplying air to the combustion cylinders of the internal combustion engine. A strap  10  electrically interconnects heater subassemblies  8  and  9  to a power connection assembly  11 . As shown in  FIG. 2 , heater subassembly  8  and heater subassembly  9  are substantially similar to one another. Accordingly, only heater subassembly  8  will be described in greater detail. 
         [0020]    Heater subassembly  8  includes a heating element  12  having a first end  13 , a second end  14  and a plurality of convolutions  16  positioned between the first and second ends. Similar elements of heater subassembly  9  have been identified with like reference numerals including a “prime” suffix. First ends  13  and  13 ′ are electrically coupled to plate  5 . Second ends  14  and  14 ′ are configured to be coupled to strap  10  by an electrical terminal  15  such that a current may be applied to heating element  12 . Heating element  12  is typically mounted within a pair of holders  17  to support the heating element during operation. 
         [0021]    As previously mentioned, the heating element and holder subassembly is positioned within an air passageway of an internal combustion engine to heat the intake air before it enters the combustion chamber. The direction of air flow is indicated by arrow  18  in the figures. The air flow travels across the width of a plurality of substantially planar portions  22 . Heating element  12  also includes a plurality of upset or flanged portions  20 . Each flanged portion  20  is positioned at one edge of heating element  12  adjacent to planar portions  22 . The upset portions  20  longitudinally extend along a majority of the length of substantially planar element portions  22 . Each flange portion includes a body  23  being connected to one of planar portions  22  by two end portions  25 . It is contemplated that the flanged portions  20  are formed during a low-cost stamping operation during the manufacture of each heating element  12 . Accordingly, it should be appreciated that heating element  12  is a contiguous, one-piece component having the flange portions and the planar portions integrally formed with one another. 
         [0022]    Flanges  20  aid in directing the air flow and providing element rigidity to minimize element movement under thermal cycling. Engine temperature testing has indicated that the thermal distribution of heat in the air charge prior to the engine cranking is improved by the additional of flanges  20 . Additionally, each flange  20  assists in changing the direction of the air flow from traveling in a first direction within an air intake tube (not shown) to a direction 90 degrees therefrom to enter the cylinders. Current trends in intake manifold and intake tube design are that the space in which the air is allowed to make a 90 degree turn is substantially reduced. The present disclosure assists in not only heating the intake air but also changing the direction of the air flow. 
         [0023]    Each heating element  12  is electrically coupled to a number of components of intake assembly  4  and electrically insulated from the remainder. As such, a variety of the components used to construct intake assembly  4  are specified to perform either an electrical insulating or an electrical conducting function. For example, each holder assembly includes insulators  24  captured within a housing  26 . Further, other electrically insulating components such as washers and/or sleeves may be used to assure a proper electrical path is maintained through intake assembly  4 . 
         [0024]      FIGS. 4-10  relate to a second embodiment intake assembly  40 . Intake assembly  40  includes a cover plate  42  configured to be positioned between an intake tube and an internal combustion head as previously described in relation to intake assembly  4 . Cover pate  42  includes an aperture  44  in communication with an air passageway providing air flow to the combustion chambers of the internal combustion engine. Heating elements  46  are shown working in cooperation with a thermal expansion joint  50 . Joint  50  is operable to interconnect ends  52  of substantially linearly extending, parallel and spaced apart heating elements  46 . The figure depicts each heating element  46  including a substantially planar portion  55  and a flange  56 . 
         [0025]    Thermal expansion joint  50  includes a shoulder bolt  58  extending through apertures  57  formed in each of heating elements  46 . Shoulder bolt  58  includes two flanges  60 . A number of conducting and insulating washers may be placed between flanges  60  of shoulder bolt  58  and nuts  62  threadingly engaged with the ends of shoulder bolt  58  to properly define the electrical current path through each of the heating elements  46 . Cover plate  42  includes a support  64  having an elongated aperture or slot  66  in receipt of shoulder bolt  58 . Shoulder bolt  58  is free to axially translate within slot  66  during operation. This is accomplished by the use of shoulder bolt  58  instead of a standard threaded fastener. Specifically, nuts  62  clamp the heating elements and washers against flanges  60 . In this manner, a compressive force is not placed on support  64  but the heating elements are captured on the shank of shoulder bolt  58 . Therefore, a sliding fit between shoulder bolt  58  and slot  66  allows heating elements  46  to expand and contract during operation without adding undesirable stress to the heating elements as would be the case if they were fixed at both ends. Because support  64  includes slot  66  at one end, the opposite end of heating elements  46  are rigidly mounted to a structure using a standard threaded fastener  70 . 
         [0026]    In another embodiment, the elongated aperture  66  is configured as an open slot  67  as shown in  FIG. 5 . In this manner a shoulder bolt  58 ′ may be constructed as a one-piece component as depicted in  FIGS. 6 and 7 . In particular, slot  67  extends a sufficient length to assure that shoulder bolt  58 ′ remains within slot  67  regardless of the temperature of heating element  46 . One-piece shoulder bolt  58 ′ includes a shank portion  59 ′ having integrally formed flanges  60 ′ spaced apart from one another. 
         [0027]      FIGS. 8-10  relate to another alternate embodiment intake assembly  100 . Intake assembly  100  is substantially similar to intake assembly  40  with the exception of variations to the thermal expansion joint. Accordingly, like elements will retain their previously introduced reference numerals. Intake assembly  100  includes a thermal expansion joint  102  having a support  104  integrally formed with a cover plate  106 . Support  104  includes an elongated aperture  108  formed as a closed slot. 
         [0028]      FIGS. 9 and 10  depict alternate embodiment shoulder bolts configured as multi-piece assemblies to extend through closed slot  108 . A shoulder bolt assembly  120  ( FIG. 9 ) includes a stepped shaft  122  having externally threaded portions  124  on each end. A center section  126  defines an increased outer diameter that is greater in size than apertures  128  extending through washers  130 . Center section  126  is sized to axially slide within close slot  108  and provide the thermal expansion relief described in relation to the previous embodiments. Center section  126  defines a pair of shoulders  132  operable to react load from nuts  134  thereby clamping heating elements  46  between shoulders  132  and nuts  134 . This arrangement assures that a clamping load is not exerted on support  104  to allow the function previously described. 
         [0029]      FIG. 10  depicts another alternate embodiment shoulder bolt assembly  150 . Shoulder bolt assembly  150  includes a first headed shaft  152  and a second headed shaft  154 . First headed shaft  152  includes an internally threaded aperture  156  in selective receipt of an externally threaded stub  158  formed on second headed shaft  154 . The two-piece assembly shown in  FIG. 10  is operable for use with closed slot  108  and provides a means for supporting heating elements  46  with a thermal expansion joint. 
         [0030]    Furthermore, the foregoing discussion discloses and describes merely exemplary embodiments of the present disclosure. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations may be made therein without department from the spirit and scope of the disclosure as defined in the following claims.