Patent Publication Number: US-6907854-B2

Title: Fan shroud with internal aspirator

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to air intake systems for internal combustion engines. More particularly, the present invention relates to such systems which employ a pre-cleaner. Specifically, the present invention relates to aspirators for supplying a vacuum to such pre-cleaners. 
     BACKGROUND OF THE INVENTION 
     Engine air intake systems for work vehicles frequently include a pre-cleaner to remove dirt particles from the intake air prior to the air filter. Many pre-cleaners require a vacuum to pull or “scavenge” dirt particles from the fresh air ingested into the air intake system. Exhaust system aspirators have been used to supply the required vacuum. An exhaust system aspirator, however, creates a restriction in the engine exhaust, raises noise levels and raises the cost of the muffler and/or exhaust pipe. Also, a check valve is needed to prevent back flow of high temperature gases into the pre-cleaner and high temperature hoses must be used. 
     An alternative approach is to use a fan shroud aspirator as a source of vacuum to a pre-cleaner. This aspirator is typically an opening in the fan shroud linked to the pre-cleaner by a hose. For cost and space savings, it is desirable to reduce the number of extraneous parts required for pre-cleaner aspiration. Modern agricultural tractors and other work vehicles sometimes require a rather long fan shroud to fill the gap between the cooling module and the fan. Thus it is desired to integrate the pre-cleaner aspirator into the fan shroud itself to reduce parts counts and costs and also to satisfy space constraints. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of the invention to provide aspiration for a work vehicle pre-cleaner. 
     Another object of the invention is the provision of a fan shroud between the fan and the cooling module of a work vehicle. 
     A further object of the invention is to provide a fan shroud for a work vehicle which has the pre-cleaner aspirator integrated therein. 
     An additional object of the invention is the provision of such a fan shroud and aspirator which is compatible with known manufacturing and assembly techniques and equipment. 
     Still another object of the invention is the provision of such a fan shroud aspirator which utilizes a minimal number of parts and optimizes the use of space under the hood of the vehicle. 
     The foregoing and other objects of the invention together with the advantages thereof over the known art which will become apparent from the detailed specification which follows are attained by a fan shroud having an integrated aspirator for use in conjunction with a pre-cleaner, the pre-cleaner having an air intake, an aspirator port, and an air exhaust, and wherein a first end of the shroud is adapted for disposal proximal to a cooling module while a second end is adapted for disposal proximal to a fan, the fan shroud comprising: an aspirator portal in an upper surface of the shroud; an aspirator having an air intake and an air outlet, the aspirator being supported inside the shroud proximal to the fan with the air outlet facing the fan; and, a first end of an aspirator hose connected to the aspirator port of the pre-cleaner and passing through the aspirator portal and a second end of the aspirator hose connected to the air intake of the aspirator so that the aspirator hose passes generally through a mid-section of the shroud; whereby the vacuum necessary for proper aspiration of the pre-cleaner is accomplished by air movement, induced by the fan, between the air intake of the pre-cleaner and the aspirator via the aspirator port and the aspirator hose. 
     In general, a fan shroud is provided having of upper and lower sections. The sections are designed to mateably engage one another at mating flanges so as to form an air passage between a fan and a cooling module of the vehicle. The upper section of shroud includes an aspirator portal in an upper surface thereof. An aspirator is provided having an air intake and an air outlet. The aspirator is supported in the lower section of the shroud proximal to the fan with the air outlet facing the fan. An engine intake air pre-cleaner unit having an air intake, an aspirator port, and an air exhaust is mounted to the shroud by aligning mounting tabs on the pre-cleaner with mounting bosses on the shroud so that the aspirator port is disposed in proximity to the aspirator portal in the upper section of shroud. One end of an aspirator hose is connected to the aspirator port of the pre-cleaner and passes through the aspirator portal. The other end of the aspirator hose is connected to the air intake of the aspirator. The aspirator hose passes generally through the middle of the shroud from the upper section to the lower section. The vacuum necessary for proper aspiration of the pre-cleaner is accomplished by air movement, induced by the fan, between the air intake of the pre-cleaner and the aspirator via the aspirator port and the aspirator hose. No additional hoses or fittings are required outside the shroud to provide aspiration to the pre-cleaner so that considerable space is conserved under the vehicle hood. 
     To acquaint persons skilled in the art most closely related to the present invention, one preferred embodiment of the invention that illustrates the best mode now contemplated for putting the invention into practice is described herein by and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to show all of the various forms and modifications in which the invention might be embodied. As such, the embodiment shown and described herein is illustrative, and as will become apparent to those skilled in the art, can be modified in numerous ways within the spirit and scope of the invention—the invention being measured by the appended claims and not by the details of the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a complete understanding of the objects, techniques, and structure of the invention reference should be made to the following detailed description and accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a fan shroud and pre-cleaner assembly according to the invention; 
         FIG. 2  is an exploded perspective view of the assembly of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view taken along the line  3 — 3  of  FIG. 2 ; 
         FIG. 4  is a perspective bottom view of an aspirator according to the invention; 
         FIG. 5  is a perspective side view of an aspirator according to the invention; and, 
         FIG. 6  is a perspective top view of the upper section of the fan shroud according to the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference now to the drawings and particularly  FIGS. 1-3 , it can be seen that a fan shroud having an internal aspirator according to the invention is designated generally by the numeral  10 . As shown the fan shroud  10  is comprised of an upper section  12  and a lower section  14  and is preferably formed of a thermoplastic or thermoset material in an appropriate conventional molding process. The upper section  12  and the lower section  14  are designed to mateably engage one another at mating flanges  16  so as to form an air passage between a fan and a cooling module of the vehicle. Accordingly, a first end  18  of the shroud  10  is adapted for disposal proximal to the cooling module (not shown) while a second end  20  is adapted for disposal proximal to the fan  22 . Thus air is drawn through the cooling module by the fan  22 . As is perhaps best shown in  FIG. 6  the upper section of shroud  10  includes an aspirator portal  24  in an upper surface  26  thereof. 
     Referring now to  FIGS. 4 and 5  an aspirator  28  is illustrated. The aspirator  28  has an air intake  30  and an air outlet  32 . The air intake  30  is essentially a nozzle which is adapted to be connected with an appropriate hose. The aspirator  28  further includes a mounting flange  34  which has a pair of fastener slots  36 . Referring again to  FIGS. 1 and 2  it will be seen that a support bracket  38  is provided for supporting the lower section  14  of the shroud  10  to the vehicle structure (not shown). A pair of support standards  40  are provided to support the upper section  12  relative to the lower section  14 . Accordingly, fasteners  42  are provided to attach the standards  40  to the bracket  38  by way of apertures  44 . Additional fasteners  46  are provided to secure the aspirator  28  to the lower section  14  of shroud  10  and the bracket  38  by way of apertures  48  and fastener slots  36 . Thus the aspirator  28  is supported in the lower section  14  of the shroud  10  proximal to the fan  22  with the air outlet  32  facing the fan  22 . 
     Referring again to  FIGS. 1-3 , an engine intake air pre-cleaner unit  50  includes an air intake  52 , an aspirator port  54  and an air exhaust  56 . In use, air is drawn in through the air intake  52 , dirt particles are “scavenged” from the air, and the cleaned air exits the pre-cleaner  50  at the air exhaust  56  which is connected to the engine intake (not shown). The pre-cleaner  50  is aspirated through the aspirator port  54  via a vacuum provided by the fan  22  as will be described below. 
     As shown in  FIGS. 1-3  and  6  a pair of pre-cleaner mounting bosses  58  are provided on the upper section  12  of the shroud  10  as shown. The mounting bosses  58  correspond to mounting tabs  60  provided on the pre-cleaner housing. Thus the pre-cleaner  50  is mounted to the shroud  10  by way of appropriate fasteners. When the mounting tabs  60  are aligned with the mounting bosses  58  the aspirator port  54  is positioned such that it is disposed in proximity to the aspirator portal  24  in the upper section  12  of shroud  10 . One end of an aspirator hose  62  is connected to the aspirator port  54  of the pre-cleaner  50  and passes through the aspirator portal  24 . The other end of the aspirator hose  62  is connected to the air intake  52  of the aspirator  28 . As should now be apparent the aspirator hose  62  passes generally through the middle of the shroud  10  from the upper section  12  to the lower section  14 . The vacuum necessary for proper aspiration of the pre-cleaner  50  is accomplished by air movement, induced by the fan  22 , between the air intake  52  of the pre-cleaner  50  and the aspirator  28  via the aspirator port  54  and the aspirator hose  62 . Thus no additional hoses or fittings are required outside the shroud  10  to provide aspiration to the pre-cleaner  50  so that considerable space is conserved under the vehicle hood. 
     Thus it can be seen that the objects of the invention have been satisfied by the structure presented above. While in accordance with the patent statutes, only the best mode and preferred embodiment of the invention has been presented and described in detail, it is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally entitled.