Abstract:
An air cleaner system for small internal combustion engines, including an air cleaner element which is received within an air cleaner chamber formed within a cover member of the engine. A substantially transparent cover covers the air cleaner chamber and permits viewing of the air cleaner element therethrough, such that an operator may easily determine whether the air cleaner element needs to be replaced. In another aspect, a cover member for attachment to the cylinder head of an engine is provided to define a rocker chamber therebetween, the cover member including a wall portion extending therefrom along the engine cylinder to define an air cooling passage or duct between the wall of the cover member and the engine cylinder. The wall of the cover member directs cooling air downwardly and closely about the engine cylinder to aid in cooling the engine cylinder.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Background of the Invention  
           [0002]    The present invention relates to small internal combustion engines for use with lawnmowers, lawn tractors, other small utility implements, or sport vehicles. In particular, the present invention relates to air cleaner systems for such small internal combustion engines.  
           [0003]    2. Field of the Invention  
           [0004]    Small internal combustion engines, such as single or twin cylinder engines, which are used for lawnmowers, lawn tractors, other small utility implements, or sport vehicles, for example, typically include air intake systems having air cleaner devices for removing dirt, dust, and other debris from the atmospheric intake air before the air is drawn into to the engine carburetor for mixing with fuel, followed by combustion within the engine.  
           [0005]    For example, in one common arrangement, an air cleaner comprises a separate box-type component including a housing which is mounted to the engine, the housing including an air inlet and an air outlet connected to the air intake system of the engine. Disposed within the air cleaner housing is an air cleaner or filter element for filtering debris from the air. Typically, the housing includes a removable cover for permitting access to the interior of the housing for inspecting and/or replacing the filter element.  
           [0006]    Problematically, because the air cleaner housing typically comprises a separate component which is mounted to the engine housing, the air cleaner housing may be difficult to integrate spatially with other engine components such as the fuel tank, the muffler, the recoil starter, and the engine shroud, for example. Additionally, an operator typically must completely remove the cover of the air cleaner housing to inspect the air filter element in order to determine whether the air cleaner element needs to be replaced.  
           [0007]    What is needed is an air cleaner system which is an improvement over the foregoing.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides an air cleaner system for small internal combustion engines, including an air cleaner element which is received within an air cleaner chamber formed within a cover member of the engine, such as a blower housing or shroud. A substantially transparent cover covers the air cleaner chamber and permits viewing of the air cleaner element therethrough, such that an operator may easily determine whether the air cleaner element needs to be replaced. Additionally, the present invention provides an air cleaner subassembly mountable to an engine housing in a single operation, including a main body portion, such as a blower housing which, together with a substantially transparent cover, defines one or more air cleaner chambers in which air cleaner elements are removably mounted.  
           [0009]    Advantageously, the foregoing arrangement, by integrating the air cleaner chamber and air cleaner element into an engine covering component, eliminates the need for a separate air cleaner housing attached to the engine, and therefore streamlines the overall engine profile and reduces the amount of space around the engine in which a known air cleaner housing would otherwise occupy. Further, the air cleaner element(s) may be easily viewed through the transparent cover(s) to determined whether the air cleaner element(s) need replacing.  
           [0010]    In another aspect, the present invention also provides a cover member for attachment to the cylinder head of an engine to define a rocker chamber therebetween, the cover member covering the valve train components within the rocker chamber. Additionally, the cover member includes a wall portion extending therefrom along the engine cylinder to define an air cooling passage or duct between the wall of the cover member and the engine cylinder. The wall of the cover member directs cooling air downwardly and closely about the engine cylinder to aid in cooling the engine cylinder.  
           [0011]    The foregoing cover member integrates a known rocker chamber cover with a wall member or duct for directing cooling air around the engine cylinder, which would otherwise comprise a separate component, thereby reducing the number of components of the engine and facilitating easier assembly of engine.  
           [0012]    In one form thereof, the present invention provides an internal combustion engine, including an engine housing; a first cover member covering at least a portion of the engine housing; a second, substantially transparent cover member attached to the first cover member, the first and second cover members together defining an air cleaner chamber therebetween; and an air cleaner element disposed within the air cleaner chamber.  
           [0013]    In another form thereof, the present invention provides an internal combustion engine, including an engine housing; a fan rotatably driven by the engine; an air cleaner subassembly mounted to the engine housing, the air cleaner subassembly including a main body portion substantially covering the fan; a substantially transparent cover attached to the main body portion, the main body portion and the cover defining an air cleaner chamber therebetween; and an air cleaner element disposed within the air cleaner chamber.  
           [0014]    In a further form thereof, the present invention provides an internal combustion engine, including a crankcase; a cylinder attached to the crankcase, the cylinder having a cylinder head portion in which at least one valve train component is disposed; and a cover member attached to the cylinder head portion, the cylinder head portion and the cover member defining an enclosed chamber in which the at least one valve train element is disposed, the cover member further including a wall portion extending therefrom along the cylinder in a direction away from the cylinder head portion to define an air passage between the wall portion and the cylinder. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0016]    [0016]FIG. 1 is a perspective view of an internal combustion engine according to a first embodiment of the present invention, including a blower housing having a pair of recessed portions within which air cleaner elements are received, and a transparent cover which permits viewing of the air cleaner elements therethrough;  
         [0017]    [0017]FIG. 2 is a first exploded view of the internal combustion engine of FIG. 1, showing the blower housing, carburetor cover, shroud, transparent cover, and one air cleaner element exploded away from the remainder of the engine;  
         [0018]    [0018]FIG. 3 is a further exploded view of the engine of FIG. 2, showing the blower housing and a pair of rocker chamber covers exploded away from the engine housing;  
         [0019]    [0019]FIG. 4 is a perspective view of an internal combustion engine according to a second embodiment of the present invention, including a blower housing defining a recessed portion in which an air cleaner element is disposed, and a transparent cover covering the recessed portion, the transparent cover permitting viewing therethrough; and  
         [0020]    [0020]FIG. 5 is an exploded view of the internal combustion engine of FIG. 4, showing the transparent cover and the air cleaner element exploded outwardly from the blower housing.  
         [0021]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrates preferred embodiments of the inventions, and such exemplifications are not to be construed as limiting the scope of the invention any manner. 
     
    
     DETAILED DESCRIPTION  
       [0022]    Referring to FIGS.  1 - 3 , internal combustion engine  20 , according to a first embodiment of the present invention, is shown. Referring first to FIG. 3, engine  20  is shown as a vertical shaft V-twin engine, including crankcase  22  to which a pair of cylinders  24  are attached. Although the present invention is described herein with reference to twin cylinder engines, the present invention is equally applicable for use with single cylinder engines or with multi-cylinder engines. Crankshaft  26  is rotatably supported within crankcase  22 , and includes an outer end extending externally of crankcase  22  to which flywheel/fan  28  is mounted. Cylinders  24  each include cylinder heads  30 , which may comprise separate components mounted to cylinders  24 , or alternatively, cylinder heads  30  may be formed integrally with cylinders  24 . Cylinder heads  30  partially define rocker chambers  32 , in which components of the valve train of engine  20  are disposed. Specifically, the valve train includes push rods  34  driven from crankshaft  26  via a camshaft, as known, and rocker arms  36  which are pivotally mounted with respect to cylinder heads for actuating intake and exhaust valves (not shown). Alternatively, the drive train may include an overhead camshaft arrangement, for example.  
         [0023]    A rocker chamber cover  38  is mounted to each cylinder head  30  of cylinders  24  to define enclosed rocker chambers  32  therebetween. Specifically, bolts  40  are inserted through apertures  42  in rocker chamber covers  38  and are threaded into bosses  44  in cylinder heads  30  to secure rocker chamber covers  38  to cylinder heads  30 . Rocker chamber covers  38  may be made from metal or from a rigid, durable plastic material, for example. Additionally, rocker chamber covers  38  each include wall portions  46  integrally formed therewith, which extend in a direction away from cylinder heads  38  generally toward crankcase  22  of engine  20 . Wall portions  46  are disposed adjacent cylinders  24  when rocker chamber covers  38  are attached to cylinder heads, and form cooling air ducts for directing cooling air from fan  28  closely around cylinders  24  of engine  22  to cool same when engine  20  is running. In known engines, separate cooling air ducts are attached to the engine cylinders or blower housing of the engines. Therefore, in the present arrangement, the integration of wall portions  46  with rocker chamber covers  38  reduces the number of components of engine  20  by eliminating the necessity of separate air duct components in addition to the rocker chamber covers, thereby reducing the cost and/or difficulty of assembly of engine  20 .  
         [0024]    Referring to FIG. 3, blower housing  50  is attached to crankcase  22  by inserting suitable bolts  40  (See also FIG. 2) through apertures  52  in blower housing  50  and into bosses  54  formed in crankcase  22 . Blower housing  50  may be formed of a suitable metal or of a plastic material, such as polypropylene or nylon, for example, and includes fan cover portion  56  having a plurality of inlet openings  58  therein through which air may be drawn by fan  28 . Blower housing  50  additionally includes a pair of cylinder cover portions  60  extending from fan cover portion  56 , each of which includes an air cleaner recess  62  formed therein. Air cleaner recesses  62  each include a plurality of inlet slots  64  allowing air flow into air cleaner recesses  62  from fan  28 , and additionally include outlet openings  66  through which air may exit air cleaner recesses  62 .  
         [0025]    Intake manifold  68  is connected to a pair of carburetors  70 , and includes a pair of inlet hoses  72  attached thereto, with opposite ends of the inlet hoses  72  attached to outlet openings  66  of air cleaner recesses  62  of blower housing  50 . Referring to FIG. 2, an air cleaner element  74 , such as a readily available air filter cartridge, for example, is removably positioned within each air cleaner recess  62  of blower housing  50 . Air cleaner element  74  generally includes rim portions  76  and filter media  78  surrounding an open central portion  80 .  
         [0026]    Additionally, a substantially transparent cover  82 , which may be made from a substantially or completely transparent plastic material such as polycarbonate, for example, is provided to cover air cleaner recesses  62 , and includes snap tabs  84  which are received within slots  86  in blower housing  50  adjacent air cleaner recesses  62  to thereby attach cover  82  to blower housing  50 . Air cleaner recesses and cover  82  together define enclosed air cleaner chambers in which air cleaner elements are disposed. As cover  82  is made from a substantially or completely transparent plastic material, air cleaner elements  74  may be easily viewed therethrough to determine whether air cleaner elements  74  have become soiled or otherwise need replacement. As shown in FIGS. 1 and 2, a single cover  82  covers both of air cleaner recesses  62  of blower housing  50 , and additionally includes a central portion which covers intake manifold  68  and inlet hoses  72 . Alternatively, as indicated by the dashed lines on cover  82  in FIG. 2, cover  82  may be formed as a pair of separate covers  82   a,  each covering one air cleaner recess  62  to define a pair of air cleaner chambers. To replace air cleaner elements  74 , cover  82  is detached to blower housing be disengaging tabs  84  from slots  86 , such as by flexing cover  82 . Thereafter, air cleaner elements  74  may be removed from air cleaner recesses  62  and replaced, followed by reattaching cover  82 . Also, blower housing  50 , air cleaner elements  74 , and cover  82  may be pre-assembled as an air cleaner subassembly, which in turn may be attached to crankcase  22  of engine  20  as described above in a single step, thereby facilitating easier manufacturing of engine  20 .  
         [0027]    Referring to FIGS. 1 and 2, shroud  90  may be attached to blower housing  50  by bolts  40  inserted through apertures  92  in shroud  90  and through apertures  52  in blower housing  50  into bosses  54  of crankcase  22 . Shroud includes lower edge  96  extending therearound, which is spaced outwardly from blower housing  50  to define a gap therebetween. Additionally, carburetor cover  94  may be attached to blower housing  50  between extending portions  60  thereof in a suitable manner to cover carburetors  70  and the linkage assemblies associated therewith. Thus, as may be seen in FIGS.  1 - 3 , the incorporation of air cleaner recesses  62  into blower housing  50  eliminates the need for a separate air cleaner housing, thereby streamlining the overall profile of engine  20 , and positioning air cleaner elements  74  toward the front of engine  20  for easy viewing through cover  82 .  
         [0028]    In operation, during running of engine  20 , fan  28  draws air from beneath lower edge  96  of shroud  90  between shroud  90  and blower housing  50  into the space between the shroud  90  and blower housing  50 , and thence through inlet apertures  56  in fan cover portion  56  of blower housing  50  and into the space between blower housing  50  and crankcase  22 . Thereafter, the air is directed outwardly of fan  28 , and enters air cleaner chambers  62  through inlet slots  64 , and passes through filter media  78  of air cleaner elements  74 , where debris is filtered from the air, into open central portion  80  of air cleaner elements  74  before exiting the air cleaner chambers through outlets  66 . Thereafter, the cleaned air passes through intake hoses  72  into intake manifold  68  and thence into carburetors  70  and into the intake system of engine  20 .  
         [0029]    Referring to FIGS. 4 and 5, another embodiment of the present invention is shown in connection with a horizontal shaft V-twin engine  100 . Engine  100  is of the type disclosed in further detail in U.S. Provisional Patent Application Serial No. 60/372,560, entitled INTERNAL COMBUSTION ENGINE, filed on Apr. 15, 2002, and in U.S. Provisional Patent Application Serial No. ______, entitled INTERNAL COMBUSTION ENGINE, filed on Aug. 12, 2002, each assigned to the assignee of the present application, the disclosure of which is expressly incorporated herein by reference. Engine  100  generally includes a crankcase and a pair of cylinders (not shown) which are covered by cylinder wraps  102 . Blower housing  104  is attached to the crankcase, and recoil starter assembly  105  is attached to blower housing  104  and to the crankcase. A fuel tank  106  is attached to cylinder wraps  102  and/or crankcase in a suitable manner.  
         [0030]    Referring to FIG. 5, blower housing  104  includes air cleaner recess  108  integrally formed therein, which includes side wall  110  and rear wall  112 . Bolts  114  are inserted through apertures in rear wall  112  to connect same to attachment flange  116  of a carburetor (not shown). Side wall  110  of air cleaner recess  108  includes a plurality of air inlet openings  118  therein, and rear wall  112  includes outlet opening  128  aligned with attachment flange  116  of the carburetor.  
         [0031]    Air cleaner element  120 , shown as an annular air filter, is received within air cleaner recess  108  of blower housing  104 , and generally includes rim portions  122  and filter media  124  surrounding open central portion  126 . When air cleaner element  120  is placed within air cleaner recess  108 , one of the rim portions  122  thereof seats against rear wall  112  of air cleaner recess  108 , with open central portion  126  of air cleaner element  120  aligned with outlet opening  128 , and inlet openings  118  disposed around filter media  124  of air cleaner element  120  and spaced therefrom. A transparent cover  130 , made from a substantially transparent or completely transparent plastic, for example, includes attachment tabs  132  which are received within slots  134  within air cleaner recess  108  of blower housing  104  to enclosed air cleaner recess  108  and define and air cleaner chamber therebetween in which air cleaner element  120  is received. To replace air cleaner element  120 , cover  130  is detached from blower housing  104  by disengaging tabs  132  from slots  134 , such as by flexing cover  130 . Thereafter, air cleaner element  120  may be removed from air cleaner recesses  108  and replaced, followed by reattaching cover  130 . Advantageously, air cleaner recess  108  of blower housing  104  is positioned in the front of engine  100 , such that air cleaner element  120  may be easily viewed through cover  130 .  
         [0032]    In operation, intake air enters air cleaner recess  108  through inlet openings  118  and passes through filter media  124  of air cleaner element, where debris is filtered from the air, into open central portion  126  of air cleaner element  120 . Alternatively, intake air may also enter air cleaner recess  108  through slotted openings  136  in shroud  104 . Thereafter, the cleaned intake air exits air cleaner recess  108  through outlet opening  128  thereof and enters the carburetor, where the intake air is mixed with gasoline to form a combustion mixture for combustion within the engine  100 .  
         [0033]    While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.