Abstract:
An engine air intake system is provided which is formed by an engine compartment. A fan and a grille screen are used to remove a portion of debris from air external to the vehicle. After the air is partially cleaned via the grille screen, it moves toward a heat exchanger carrying a portion of the remaining debris with it. A portion of the debris may fall out of the air via gravitational effects. A portion of the air then moves up and into an entrance passage for an air intake duct that is integrated with the hood of the engine enclosure, this portion having been further cleaned via debris passage to and through the heat exchanger as well as gravitational effects. The air then travels through the air intake duct and passes through an air filter where a portion of the remaining debris is removed prior to the air being supplied to the engine intake.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/182,420, entitled “INTEGRATED AIR INTAKE SYSTEM”, filed May 29, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to the structure and operation of air intake systems and methods of supplying intake air to internal combustion engines. More specifically, it relates to a method, system and structure for supplying ambient or non-preheated air to an internal combustion engine for a work vehicle or mobile construction machine such as, for example, a wheeled feller buncher. 
       BACKGROUND OF THE INVENTION 
       [0003]    Most mobile construction machines employ above-hood engine air intakes. The above-hood air intake is usually covered by a shield to prevent the entrance of rain and other precipitation. Above-hood air intakes are typically designed to be low-profile, i.e., have as small of a visual signature as possible. However, these intakes are required to be high enough to minimize the entry of dust and other debris settling near the hood and far enough from the exhaust stack associated with these machines to minimize the intake of preheated air. Pre-cleaners are typically used in above-hood air intake designs to remove some of the debris from the intake air and, thereby, extend engine air filter life. 
         [0004]    As previously indicated, conventional above-hood air intake systems for work vehicles tend to obstruct visibility for the work vehicle operator. This is a consequence of attempting to meet the noted demands of locating the air intake (1) high enough to eliminate or minimize the entry of dust and debris from the hood and (2) far enough from the exhaust stack to eliminate or minimize the intake of preheated air. These disadvantages are only intensified by the relatively large pre-cleaners that are often attached to the entry point of such systems in high debris environments. 
         [0005]    Some mobile construction machines are provided with conventional under hood air intake systems having air intake tubes with inlet openings located in the engine compartment. When these systems have perforations in the hood of the engine compartment, the inlet opening is arranged to prevent the intake of rain and other precipitation. Thus, the inlet opening of the air intake is angled such that the intake air enters in a direction that is horizontal to or at least partially opposite to the direction of the precipitation as it enters the engine compartment. Other under hood air intake designs include air intake tubes that are routed to compact cooling package areas where the air inlets are located in areas separate from the engine compartment. 
         [0006]    A major disadvantage of many conventional under hood air intake systems where the intake port is located in the engine compartment is that they tend to intake preheated air via convection and radiation with respect to the engine. This is accentuated when these systems have perforations in the hood as the intake port must be angled away from the perforations and more toward the engine compartment with air preheated by heat exchanger(s) and the engine. Other under hood air intake designs tend to avoid this problem but all under hood designs tend to use only screens and filters to remove debris as the use of pre-cleaners under the hood tends to: (1) take up too much precious space, i.e., premium space; and (2) the inconvenience caused by the debris typically ejected by such devices. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention overcomes each of the above disadvantages by providing an air intake system integral to and formed by a hood of an engine enclosure as well as other conventional components within the engine enclosure. The engine enclosure is formed by at least the hood, two sidewalls, a grille and a screen. An insulated air duct forms an integral part of the hood and is in communication with a filter for engine air intake. The air entering the air duct may be moved into the engine enclosure via a fan for the purpose of moving air from the ambient surroundings outside of the vehicle to a location inside the vehicle and, typically, through a heat exchanger. The air may also be pre-cleaned by a screen as well as relative movement between debris and air prior to and after pre-cleaning of the air by the screen. The entrance to the air duct is preferably located such that the ambient air entering the air channel tends toward ambient temperature, i.e., air that has not been preheated via passage through the heat exchanger. Thus, a preferable location for the entrance to the air duct is, horizontally, between the screen and the heat exchanger and, vertically, toward the top of the screen and the heat exchanger. Further, the entrance passage is preferably substantially orthogonal to the axis of the fan or at an angle greater than 90 degrees to the axis of the fan or the flow direction of the air. Such an arrangement gives the air a chance for a first pre-cleaning via the screen as well as a second pre-cleaning via the general inability of debris to change direction and move upwards and into the entrance passage to the same extent as air. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments of the invention will be described in full detail with references to the following Figures, wherein: 
           [0009]      FIG. 1  is a view of a work vehicle in which the invention is used; 
           [0010]      FIG. 2  is an oblique view of a rear portion of the vehicle illustrated in  FIG. 1 ; 
           [0011]      FIG. 3  is an oblique cutaway view of the engine enclosure showing a view of an exemplary air intake system; 
           [0012]      FIG. 4  is an oblique cutaway view showing the exemplary air intake system of  FIG. 3  illustrating a connection between the filter and a turbocharger; 
           [0013]      FIG. 5  is a side view cutaway of a portion of the air intake system of  FIGS. 3 and 4  illustrating a bolted connection between the screen and the grille of the vehicle of  FIG. 1 , a sealed assembly between first and second portions of the air channel, and an entrance passage to the air channel; 
           [0014]      FIG. 6  is a close-up view of a portion of  FIG. 5   
           [0015]      FIG. 7  is a rear view cutaway of a cylinder through the air channel for easy access to a fill cap for the heat exchanger; 
           [0016]      FIG. 8  is a forward cutaway of the engine enclosure showing the interface between the air filter duct and the air intake duct; 
           [0017]      FIG. 9  is a view of first air intake duct portion isolated; and 
           [0018]      FIG. 10  is a view of the second air intake duct portion isolated. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]      FIG. 1  illustrates an exemplary embodiment of a work vehicle in which the invention is used. The particular work vehicle illustrated in  FIG. 1  is a wheeled feller buncher  1 ; an articulated vehicle having a front body portion  20  connected to a rear body portion  30  via pivots  40 , the wheeled feller buncher  1  being steered by pivoting of the front body portion  20  relative to the rear body portion  30  in a manner well known in the art. The rear body portion  30  includes an engine enclosure  100  having a first sidewall  101 , a second sidewall  102  and a hood  100   a  with an integrated air intake duct  110  and a supporting structure  113  ( FIG. 5 ). 
         [0020]      FIGS. 2 and 3  illustrate that, in this exemplary embodiment, a grille screen  117  forms a portion of the engine enclosure  100 . As shown in  FIGS. 5 and 6 , in this particular embodiment, the grille screen  117  includes a grille bar support  117   a , a plurality of grille bars  117   b  and a screen  118  with a multiplicity of holes, each having an approximate diameter of 2.5 mm. Each grille bar  117   b  is, in this embodiment, welded to the grille bar support  117   a . The grille screen is assembled by locating the screen  118  between the grille bar support  117   a  and the plurality of grille bars  117   b  as shown in  FIGS. 5 and 6  and attaching it to the grille bar support  117   a  via a plurality of fasteners such as, for example, the bolt  119  and welded nut  119   a  arrangement shown in  FIGS. 5 and 6 . The grille screen  117  acts as a door for the engine enclosure  100 ; it is pivotally connected to a hinge  117   c  and swings outwardly and away from the vehicle in a manner well known in the art. The grille bar support  117   a  and the plurality of grille bars  117   b , among other things, serve a decorative function and act as a support and protective structure for the screen  118 . 
         [0021]      FIG. 3  also shows the intake air duct  110  which, in this embodiment, extends along a significant portion of the length L of the hood  100   a  as well as a significant portion of the width W of the hood  100   a . As illustrated in  FIG. 3 , the air intake duct  110  is an assembly including a first intake air duct portion  112  and a second intake air duct portion  111 . As illustrated in  FIG. 7 , the first air intake duct portion  112  is formed by two channels, including; a lower channel  112   d  and an upper channel  112   c  forming a rear outer shell of the hood, i.e., a rear hood cover  112   g  with flanges  112   h . The lower and upper channels  112   d  and  112   c  are welded along their lengths at W 1 , W 2 , W 3  and W 4 . As shown in  FIGS. 3 and 5 , a rectangular opening toward the rear end of the first air intake duct portion  112  forms a part of an air entrance passage  112   b  which allows air to enter the air intake duct  110  in a direction that is generally orthogonal to the flow of air between the grille screen  117  and the heat exchanger  116 . An air guidance structure  113  completes the air entrance passage  112   b . The air guidance structure is welded to the frame of the vehicle in a well known manner. Seals  113   a ,  113   b  are provided between the first air intake duct portion  112  and the air guidance structure  113  to provide a barrier to leakage of air into or out of the entrance passage  112   b  as air from the air guidance structure  113  moves into the first intake air duct portion  112 . 
         [0022]    Welded to each channel and vertical thereto is a cylinder  112   a  providing an access hole  116   b  to a fill cap  116   a  of the heat exchanger  116 . The cylinder  112   a  is welded along its circumference at each end to the upper and lower channels  112   c ,  112   d  at W 5  and W 6 . 
         [0023]    As illustrated in  FIGS. 1 and 8 , the second air intake duct portion  111  is formed via first and second forward channels  111   c ,  111   d  and a supporting structure which is formed by a plate  111   b  welded along its length, at W 7  and W 8  to the internal side of a hood shell, i.e., forward hood structure  111   a  which is, in this case, of trapezoidal shape cross sectionally. As shown in  FIG. 8 , the ends of the first and second forward channels  111   c ,  111   d  are attached to the plate  111   b  via weldments along their lengths at W 9 , W 10 , W 11  and W 12  as illustrated. As illustrated a gap  111   f  is formed between the first and second forward channels  111   c ,  111   d . The width G 1  of the first gap  111   f  and the substantially static air therein provide insulation, i.e., a barrier to the transfer of heat from inside the engine enclosure  100 . As shown in  FIG. 8  a second gap  111   e  is formed between the plate  111   b  and the hood structure  111   a . The width G 2  of the second gap  111   e  as well as the static air therein provide insulation, i.e., a barrier to the transfer of heat between the outside ambient air and the air passing through the second air intake duct portion  111 . In this exemplary embodiment, G 1  is approximately 19 mm and G 2  is approximately 22 mm. The width of the air intake duct  110  and the gap widths internal to the air intake duct  110  providing the insulation are designed to optimize air flow within the intake air duct  110  while maintaining improved visibility for the operator, i.e., a low hood profile. The pressure for optimal flow varies with configuration but, is, in this exemplary embodiment, approximately 3.3 kPa. This value is subject to change with changes in the configuration and desired performance demands from the overall design. 
         [0024]    The rear hood cover  112   g  of the first air intake duct portion  112  and the forward hood structure  111   a  of the second air intake duct portion  111  are bolted to the frame in a manner well known in the art. As illustrated in  FIG. 5 , the lower channel  112   d  is longer than the upper channel  112   c . As illustrated in  FIGS. 5 ,  7  and  8 , upon assembly of the first air intake duct  112  to the second air intake duct portion  111 , the upper channel  112   c  butts up against a seal  110   a  to prevent debris and water from the external environment from entering the air intake duct  110  at the interface between the first air intake duct portion  112  and the second air intake duct portion  111 . As illustrated in  FIG. 5 , the lower channel  112   d  slides into the second air intake duct portion  111 . A seal  110   b  is also provided to prevent leakage of air into and out of the air intake duct  110  at the interface between the first air intake duct portion  111  and the second air intake portion  112 ; this seal  110   b  provides a barrier to air flow between air in the engine enclosure  100  and the air intake duct  110 . Both of the seals  110   a ,  110   b  are, in this exemplary embodiment, attached to the second air intake duct portion in a manner well known in the art. A labyrinth pattern at the forward end of the upper channel  112   c  provides extra sealing against external moisture and debris. 
         [0025]    As illustrated in  FIGS. 3 and 8 , a sealed opening  111   j  is provided for a first air filter duct  114   a  toward the forward end of the second air intake duct portion  111 . The sealed opening is provided by a cylinder  111   g  welded toward its ends to bottom portions of the first and second forward channels  111   c ,  111   d . Holes, in this exemplary embodiment, are provided in the first and second forward channels  111   c ,  111   d  to allow for passage of the air filter intake duct  114   a  into the second air intake duct  111 . A fifth seal  111   h  is attached to the outside surface of second forward channel  111   d  in a manner well known in the art to prevent leakage of air at the interface of the second air intake duct portion  111  and the air filter duct intake  114   a  as air flows from the second air intake duct portion  111  into the air filter intake duct  114   a  and eventually to the air filter  114  to which the air filter intake duct is attached. As shown in  FIGS. 3 and 4 , the air filter  114  is attached to the frame in a manner well known in the art, e.g., straps  114   b.    
         [0026]    As illustrated, an air filter supply duct  120  provides communication between the air filter  114  and a turbocharger  121 . An engine  55  operates in conjunction with the turbocharger  121  in a manner well known in the art. As the engine operates, the heat and pressure of the exhaust gas passes to the turbocharger  121  which lowers the pressure in the supply duct and, thereby, lowers the pressure in the air filter  114 , the air filter intake duct  114   a  and the air intake duct  110 . The lower pressure in the air intake duct  110  causes the flow of air into the air entrance passage  112   b.    
         [0027]    In operation, the fan  115  draws outside air, i.e., a first ambient air through the grille screen  117 . As the air passes through the grille screen  117 , the screen blocks the passage of larger debris, allowing only debris that may pass through the holes  118   a  provided in the screen. This results in a second ambient air, i.e., air from which a portion of debris has been removed via the screen  118 . As the second ambient air moves toward the heat exchanger  116  other debris tends to move along with it or to fall out of it via gravitational effects. Demands of the engine, communicated via the turbocharger, cause a portion of the air between the screen  118  and the heat exchanger  116  to flow into the entrance passage  112   b . The air flowing into the entrance passage  112   b  constitutes a third ambient air as some debris has been removed from it via the above gravitational effects and the passage of some debris to and through the heat exchanger. Some of the remaining debris lacks sufficient ability to turn upwards and move into the entrance passage  112   b  to the same extent as air. 
         [0028]    Third ambient air, upon moving into the first air intake duct portion  112  must make a sharp turn as the entrance passage  112   b  is, in this exemplary embodiment, orthogonal to the air intake duct  110 . Some additional debris may drop out and be removed at this point. The third ambient air passes through the air intake duct  110  and into the air filter  114  via the air filter intake duct  114   a . The filter  114  then removes another portion of the debris and the air emerging from the filter enters the filter supply duct  120 . The air entering the filter supply duct  120  is a fourth ambient air, i.e., third ambient air with a portion of the debris removed by the filter  114 . The fourth ambient air is then supplied to the turbocharger via the filter supply duct  120  and then supplied to the engine  55  via the turbocharger  121  in a manner well known in the art. 
         [0029]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims. For example, an air intake duct may be constructed and insulated using several alternative methods. Some of these methods might include: (1) forming a second air intake portion by using fully formed inner and outer ducts; (2) providing heat insulation for both portions of an air intake duct; (3) making an air intake duct a single piece; (4) locating the air intake duct at an angle greater or less than that of the hood; (5) locating a fan and heat exchanger at a level that is lower than that of the screen. The plates, channels and hood covers of this particular embodiment are metallic but could, conceivably, be formed from other materials of high strength or low conductivity, etc. Other variations of materials, arrangement and construction would apply to the air duct as well as any other portion of the invention described herein.