Abstract:
An all terrain or straddle type vehicle is provided with an air intake system having an air intake pipe with reduced length thereby avoiding unnecessary vibration which may adversely affect the fuel-to-air ratio of the engine, thereby improving engine performance. Also an inlet end of the air intake pipe is positioned so that the vehicle&#39;s capability for traversing water of a predetermined depth is improved. The height of the inlet end of the intake pipe is greater than the predetermined depth of the water to protect against water entering the air intake pipe due to encountering a water wave created in front of the vehicle that has a depth greater than the predetermined depth of the water. Additionally, openings in rear fenders of the vehicle channel intake air to both a radiator/fan assembly and the air intake system.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 60/229,027 filed on Aug. 31, 2000, the entirety of which is hereby incorporated into the present application by reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an improved straddle type all terrain vehicle (ATV) and more particularly to the structure, placement and orientation of an air intake within the ATV. 
     2. Description of Related Art 
       FIG. 1A  shows a related art ATV  700  including a frame  702 , a pair of front wheels  704 , and a pair of rear wheels  706 . The frame  702  has mounted thereto a body  708 , which is shown to include front facie  710  and rear fenders  712 . Additionally, the ATV  700  includes a fuel tank  714  mounted thereto. 
     For the ATV  700  shown in  FIG. 1A , the rear wheels  706  are supplied power from an engine  718 . The engine  718  generates power by combusting a mixture of fuel and air. The fuel is delivered to the engine  718  from the fuel tank  714  by a suitable means, such as a fuel pump. Air is pulled from the atmosphere through an air intake system, indicated at  720 , mixed with the fuel in a carburetor  743 , and combusted within a chamber of the engine  718 . An inlet  722  of air intake system  720  is positioned between the seat  710  and fuel tank  714 . Accordingly, the inlet  722  is protected from debris and water entering therethrough. 
       FIG. 1B  shows a schematic view of the air intake system  720  and engine  718 . As shown, the air intake system  720  includes a pair of intake tubes  730 , which on one end thereof provide the inlet  722 , and are connected to a noise suppressing enclosure or silencer  732 . The silencer  732  is a substantially voluminous enclosure, which serves to attenuate intake roar of the engine  718 . The silencer  732  includes a hollow molded body  734  with an upwardly facing opening  736 . A closure member (e.g., lid)  738  is detachably mounted (such as with clips  739 ) to the body  734  thereby sealing the opening  736 . It is noted that the sealing of the opening  736  may be facilitated by a pliable sealing member  740  disposed between the body  734  and closure member  738 . The silencer  732  is also connected to an intake duct  742 , which is connected at an opposite end to the carburetor  743 . As shown, an air filter  744  is disposed within the silencer  732  and may be connected to the end of duct  742  to filter or otherwise separate particulates through the air flowing from the air intake system  720  prior to delivery to the carburetor  743 . As shown in  FIG. 1A , the silencer  732  is positioned just behind the engine  718 . The intake tubes  730  extend from the silencer  732 , along an upper portion of the engine  718 , to the position between the fuel tank  714  and the seat  710 . 
     The main drawback of the air intake system  720  shown in  FIGS. 1A and 1B , stems from the proximate positioning of the air intake  720  relative to the engine  718 . In particular, the silencer  732  is positioned rearwardly of the engine  718  and adjacent thereto. Additionally, the intake tubes  730  are positioned above the engine  718 , between the engine  718  and the seat  710 , as is conventional. As such, the intake tubes  730  and silencer  732  are exposed to a substantial amount of heat generated by the engine  718 , which serves to raise the temperature of intake air prior to combustion. Relatively high temperature intake air disadvantageously reduces engine efficiency and power output. 
       FIG. 2A  is a perspective view showing a related prior art ATV  100  described in application Ser. No. 09/057,652 incorporated by reference into the provisional application No. 60/229,027 referenced above. The ATV  100  includes a pair of front wheels  102  and a pair of rear wheels  103 . The front wheels  102  are covered by front fenders  117  and the rear wheels  103  are covered by rear fenders  116 . A front rack  105  is provided above the front fenders  117  and the rack  106  is provided above the rear fenders  116 . A pair of apertures or ventilation openings  120 , provided in the rear fenders  116 , supply intake air to a radiator and fan assembly  170  (FIG.  2 B), which is generally beneath a seat  107 . A pair of handle bars  110  is used to steer the ATV  100 . 
       FIG. 2B  is a top plan view of the ATV  100  shown in  FIG. 2A , with the seat  107  being removed and the front and rear fenders  116 ,  117  being shown in phantom. The front and rear wheels  102  and  103  are supported by a main frame  121 , while a subframe  122 , which is connected to the main frame  121  through joints  124 , supports the radiator and fan assembly  170 . A suitable type of power unit, e.g., an engine  150 , is preferably capable of simultaneously driving the front and rear wheels  102  and  103  through a suitable transmission, although rear wheel drive only ATVs are also contemplated. The ATV  100  also includes a carburetor  152 , an exhaust pipe  154 , a muffler  156 , and an air intake system  200 , which is shown in greater detail in FIG.  3 . 
       FIG. 3  is a schematic view illustrating an intake air system  200 . An inlet end  212  of a front air intake pipe  214  is positioned at the front of the ATV  100  adjacent the steering column, just below a mounting plate  115  for mounting equipment, e.g., an instrument panel and/or a dash board. The inlet end  212  is positioned at substantially the highest point of the ATV  100  to substantially eliminate entry of mud or water caused either by immersion when traversing relatively deep water or by splashing when traversing wet terrain. The front air intake pipe  214  is connected to a sleeve  216  and a rear air intake pipe  217  that leads to the air box  201 , which is positioned just below a rear portion of the seat  107 . Clamps  210  secure the front air intake pipe  214  to the sleeve  216 , and the sleeve  216  to the rear air intake pipe  217 . Intake air from the air box  201  is supplied to the carburetor  152  using a hose  206  that is held by a clamp  210  to the carburetor  152 . Air is supplied to an engine valve cover (not shown) and the engine  150  using a vent hose  222 , clamps  218  and  219 , PCV valve  221 , oetiker clamp  227 , vent hose  226 , “Y” fitting  228 , hoses  229  and  230  and fitting  233 . The air filter  155  is placed in the air box  201  along with a foam member  220 . Air intake tubes  211  fit within the air filter  155 . A cover  226  is secured by cover brackets  232  to the air intake box  201 . 
     The related art air intake system  200  suffers from at least two main drawbacks. The first main drawback is that the cumulative length of the air intake pipes  214 ,  216  and  217  may create vibration and sound resonance that affects the fuel-to-air air ratio in the carburetor  152 . Vibration and sound resonance adversely affect air pressure in the carburetor  152 , thereby causing fuel-to-air to ratio to be either lean or rich, therefore adversely affecting performance of the engine. 
     The second main drawback to the related art intake system  200  is schematically illustrated in FIG.  4 . In some circumstances, the ATV  100  is used in conditions where it is necessary to cross bodies of water, such as rivers and streams. It is for this reason that the inlet end  212  of the front end intake pipe  214  is positioned at the highest point of the ATV  100 , near the steering column and just below the mounting plate  115 , as discussed previously. However, when the ATV  100  is crossing a deep stream having a predetermined depth D nominal , a wall of water or wave W having a depth D max  greater than the predetermined depth D nominal  is created and travels upwardly against the front of the ATV  100 . This phenomenon can introduce water into the inlet end  212  of the front air intake pipe  214 , which is undesirable. Typically, the wave W dissipates just rearward of the front wheels  102 , and the depth D wake  of the water behind the wave W is less than the predetermined depth D nominal  of the water because of the wake created by the ATV  100 . 
     Furthermore, both of the prior art intake systems  200  and  720  share an additional drawback in that the respective inlets  212 ,  722  are located just in front of the rider. With this arrangement, the rider is exposed to a substantial degree of noise and vibration emanating from the inlets  212 ,  722 . 
     SUMMARY OF THE INVENTION 
     It is one aspect of the invention to avoid the main drawbacks of the related art, including positioning an air intake system relative to the engine such that air traveling through the air intake system is not exposed to relatively high temperatures prior to delivery to the engine. 
     It is another aspect of the invention to avoid other drawbacks of the related art, including providing an ATV with a short intake pipe that avoids sound resonance and vibration that can adversely affect the fuel-to-air ratio in the carburetor. 
     It is another aspect of the invention to provide an ATV in which the inlet end of air intake pipe is positioned to avoid interaction with a water wave created at the front of the vehicle when the vehicle travels through water. 
     It is yet another aspect of the present invention to provide an ATV in which existing ventilation openings on the ATV can he used to supply intake air to both the radiator and fan assembly and the air intake system. 
     It is yet another aspect of the present invention to provide an ATV in which the inlet end of the air intake pipe is positioned to prevent exposure of the rider to a substantial degree of noise and vibration emanating from the inlet end. 
     According to one preferred embodiment of the present invention, an all terrain vehicle having a frame and front and rear wheels suspended from the frame includes a pair of rear fenders attached to the frame, the rear fenders having at least one ventilation opening, an engine mounted on the frame between the pair of rear fenders, the engine providing motive power to at least one of the pair of front and rear wheels, and an air intake box connected to the frame and supplying intake air to the engine, the air intake box including an intake pipe connected to and receiving intake air from the at least one ventilation opening. 
     In embodiments, the vehicle may further comprise a radiator connected to the frame, the radiator drawing intake air from the at least one ventilation opening. In addition, the vehicle may comprise a seat located between the rear fenders, the intake pipe including an inlet end positioned adjacent a rear lateral portion of the seat. The inlet end of the intake pipe is preferably positioned above the rear wheels so as avoid interaction with a water wave created at the front of the vehicle when the vehicle travels through water. 
     According to another preferred embodiment of the present invention, an all terrain vehicle comprises an engine, a seat having a front portion positioned above the engine, an air intake system operatively connected to the engine, and at least one opening adjacent a rear portion of the seat and supplying intake air to the air intake system. 
     In embodiments, the vehicle further comprises rear fenders positioned adjacent the engine, wherein the at least one opening is located on at least one of the rear fenders. The air intake system may also include an air box having an intake pipe positioned so as to avoid interaction with a water wave created at the front of the vehicle when the vehicle travels through water. Also, the seat may be located between the rear fenders, and the air intake system may include an intake pipe having an inlet end positioned adjacent the rear portion of the seat. 
     According to another preferred embodiment of the invention, a straddle type motor vehicle having front and rear wheels and being capable of traversing water having a predetermined depth includes an engine, an air intake box positioned adjacent the engine and at least one opening in communication with the air intake box. The at least one opening is positioned on the vehicle rearward of the front wheels and so that the height of the opening is greater than the predetermined depth of the water. The position of the at least one opening also helps to avoid water entering the at least one opening due to encountering a water wave created in front of the vehicle that has a wave depth greater than the depth of the water. 
     The vehicle may also include a frame that mounts the engine, and rear fenders may be attached to the frame, with the at least one opening being provided within at least one of the rear fenders. The at least one opening may comprise at least one opening provided on each of the rear fenders, and a radiator may be connected to the frame, the radiator being in communication with the at least one opening. The air intake box may include an intake pipe having an inlet end adjacent to only one of the rear fenders. Also, the vehicle may further comprise a seat provided between the rear fenders, the air intake box including an intake pipe having an air inlet positioned adjacent a rear lateral portion of the seat. 
     According to still another preferred embodiment of the invention, an all terrain vehicle having front and rear wheels comprises a frame from which the wheels are suspended, an engine mounted on the frame, a fender structure overlying at least the rear wheels, the fender structure including at least one aperture, and an air intake system in communication with the engine, the air intake system including an air box mounted on the frame, the air intake box having an intake pipe having an inlet end, the intake pipe being fastened with respect to the fender structure such that the inlet end is in communication with the aperture in the fender structure and is positioned rearward of the front wheels and higher than the rear wheels. 
     In embodiments of an all-terrain vehicle, the aperture in the fender structure may be a ventilation opening that supplies intake air to a radiator positioned adjacent the engine. Also, the intake pipe may include a clip that attaches to the fender structure. 
     These and other aspects of preferred embodiments of the invention will be described in or apparent from the following detailed description of preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will be described in conjunction with the following drawings, wherein: 
         FIG. 1A  is a perspective view illustrating a related art ATV; 
         FIG. 1B  illustrates an air intake system of the related art ATV shown in  FIG. 1A ; 
         FIG. 2A  is a perspective view illustrating another related art ATV; 
         FIG. 2B  is a plan view of a frame of the related art ATV shown in  FIG. 2A ; 
         FIG. 3  illustrates an air intake system of the related art ATV shown in  FIGS. 2A and 2B ; 
         FIG. 4  is a schematic view of the related art ATV shown in  FIGS. 2A and 2B  as it travels through water; 
         FIG. 5  is a side view illustrating an air intake system according to one preferred embodiment of the invention; 
         FIG. 6  is a rear perspective view of the air intake system of  FIG. 5  attached to a frame according to one preferred embodiment of the invention; 
         FIG. 7  is a front perspective view illustrating the air intake system and frame shown in  FIG. 6 ; 
         FIG. 8  is a top view of the air intake system of  FIG. 5  illustrating one embodiment of the manner in which the air intake box is connected to both the frame and fender structure; 
         FIG. 9  is an enlarged cross-sectional view along line IX—IX of  FIG. 8 ; 
         FIG. 10  is a cross-sectional view along line X—X of  FIG. 8 ; 
         FIG. 11  is a detail view of a portion of  FIG. 10 ; 
         FIG. 12  is a front perspective view illustrating rear fenders with ventilation openings according to one preferred embodiment of the invention; 
         FIG. 13  is a front perspective view according to one embodiment of the invention illustrating the cover portion and the rear fenders in a disassembled state without the seat; 
         FIG. 13A  is a top view of the cover portion and rear fenders shown in  FIG. 12 ; 
         FIG. 13B  is a front perspective view illustrating anther preferred embodiment of the invention; and 
         FIG. 14  is a schematic view illustrating one advantage of the placement of the inlet end of the air intake pipe when the vehicle travels through water, according to one preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 5  illustrates an air intake system  300  according to one preferred embodiment of the invention. The air intake system  300  includes an air box  301 , which is a closed container provided with a lid  314  that is secured to a main body  351  of the air box  301  using clips  313 . The air box  301  is generally positioned beneath the seat  507  ( FIG. 12 ) towards a rear portion of the ATV  500  (FIG.  12 ). It is contemplated that the specific construction and placement of the air box  301  may be altered from that shown and described herein. 
     The air intake system  300  includes an air intake pipe  302  connected to the main body  351  of the air box  301 , toward the rear of the ATV  500 . The air intake box  301  includes a port  303  that is connected to and provides intake air to an outlet pipe  304  that leads to a carburetor  352  (FIGS.  6  and  7 ). The air box  301  also includes ports  305 A and  305 B, which are connected to vacuum pipe  306 A and engine ventilation pipe  306 B, respectively. The vacuum pipe  306 A is connected to the carburetor  352  and applies vacuum pressure from the carburetor  352  (generated by the engine  600 ) on a valve element (not shown) situated within the air box  301 . It is contemplated that the valve element may be used to control the quantity of intake air allowed to enter the outlet pipe  304  from the air box  301 . The engine ventilation pipe  306 B serves to vent components of engine  600  such as a crankcase and valve cover through respective ventilation pipes  307 ,  308 . As shown in  FIG. 5 , engine ventilation pipe  306 B includes a “Y” fitting  311  to connect both the crankcase and valve cover of the engine  600  via pipes  307 ,  308 , respectively to the engine ventilation pipe  306 B. There are, of course, different configurations possible for the input to and output from the air box  301  dependent upon the particular design of the engine  600 . 
     The air box  301  includes an extension  353  provided on a portion of the air box  301  facing the front of the ATV  500 . The extension  353  is used to attach the air box  301  to the frame  120  (FIGS.  6  and  7 ), and the air box  301  also includes a bottom wall  330  that includes a pin  332  for engaging an aperture provided on the frame  120 , as described below. 
       FIGS. 6 and 7  are rear and front perspective views, respectively, illustrating one preferred embodiment for attaching the air box  301  to the frame  120 . The frame  120  may have a subframe similar to that shown in FIG.  2 B. Additionally, the frame  120  may include other members. 
     As compared to the arrangement shown in  FIG. 3  in which the inlet end  212  of the intake pipe  214  is provided beneath the mounting plate  115 , the inlet end  312  of the intake pipe  302  is provided close to the air box  301  and towards the rear of the vehicle. One important advantage to this arrangement is that the length of the intake pipe  302  is significantly reduced as compared to the combined length of the intake pipes  214 ,  216  and  217  shown in FIG.  3 . As such, the intake pipe  302  is much less apt to vibration, thereby helping to avoid or avoiding sound resonance that can adversely affect the fuel-to-air ratio in the carburetor  352 . Thus, the fuel-to-air ratio in the air intake system  300  can be more precisely controlled to provide for better engine operating performance. Further the air intake system  300  has less parts and is also easier to assemble and maintain, thereby reducing costs for maintenance, labor and parts. 
     As shown in  FIG. 6 , the frame  120  also includes a support plate  126  for supporting the bottom wall  330  of the air box  301 . As shown in  FIG. 7 , the support plate  126  includes an aperture  122  for receiving the pin  332  of the air box  301 . 
       FIG. 8  is a top plan view illustrating one preferred connection arrangement between the air intake system  300  and the frame  120 .  FIG. 8  also illustrates one preferred arrangement for connecting the air intake system  300  to a connecting wall  502  that is positioned between and preferably formed integrally with the fender structure, e.g., rear fenders  516  (FIG.  12 ). Referring back to  FIG. 6 , the frame  120  includes a frame adapter member  125  connected to the frame  120  using, for example, a standard nut and bolt assembly  142  (FIG.  8 ), or other suitable fastener. The adapter member  125  includes a lateral extension  127  on each side of a main support bar  123  of the frame  120 . The lateral extension towards the air box  301  includes a bolt hole through which a bolt  340  ( FIG. 9 ) extends to secure the air box  301  to the adapter member  125  of the frame  120 . As shown in  FIG. 9 , which is an enlarged cross-sectional view along line IX—IX of  FIG. 8 , the extension  353  of the air box  301  and one of the lateral extensions  127  of the frame  120  (on the side of the main support bar  123  facing the air box  301 ) are bolted together using the bolt  340  and nut  342 . 
     As shown in  FIGS. 8 ,  10 ,  13  and  13 A, the air intake pipe  302  extends beneath the connecting wall  502  and extends upwardly through a bottom wall  506  defined by one of a plurality of channels  590  ( FIG. 13 ) that are preferably formed as part of the fender structure. Referring to  FIG. 13A , the bottom wall  506  may be provided with a U-shaped aperture  505 , through which the intake pipe  302  extends. Alternatively, or in addition, the intake pipe  302  can be guided through an aperture (not shown) formed in a side wall of the connecting wall  502 , rather than in the bottom wall  506  of, one of the channels  590 . As shown in  FIGS. 8 and 11 , the connecting wall  502  also includes a slot  504  for receiving a fastener formed as part of the intake pipe  302 . For example, a clip  315  made of a resilient material and integrally formed with or connected to the intake pipe  302  can be provided to fasten the intake pipe  302  to the connecting wall  502 . The detail view of  FIG. 11  shows that the clip  315  extends through the connecting wall  502  to secure the intake pipe  302  with respect to the connecting wall  502  such that the inlet end  312  of the intake pipe  302  is fastened in a predetermined position with respect to an aperture or a ventilation opening  520  ( FIG. 13 ) on the fender structure, e.g., the rear fenders  516  of the ATV, as described below. 
     Like the ATV  100  shown in  FIG. 1 , the ATV  500  according to the invention has fender structure that includes rear fenders  516  on either side of a seat  507 , as shown in  FIGS. 12 and 13 . The rear fenders  516  include apertures or ventilation openings  520 . Also, since the power unit (engine) is positioned at least in part beneath the seat  507 , additional ventilation openings  547  are preferably provided in the base portion of the seat  507  in order to ensure proper ventilation of the engine compartment. The ventilation openings  547  preferably extend to the side of the seat  507  since accessories, which could block the openings, may be provided in front of the base portion of the seat  507 .  FIG. 12  also shows protection grills  530  that are connected to a cover portion  513 . The protection grills  530  prevent large objects from entering into the channels  590  ( FIG. 13 ) that lead to the radiator and fan assembly  170 , which are more fully described in U.S. Pat. No. 6,296,073 and A allowed pending application Ser. No. 09/057,652. 
       FIG. 13  schematically shows the position of the airbox  301  next to the connecting wall  502  between the rear fenders  516 . The intake pipe  302  of the air box  301  is guided beneath the connecting wall  502  and through a bottom wall  506  of the channels  590  (via aperture  505 ) so that the inlet end  312  has access to intake air that enters at least one of the ventilation openings  520 . The slot  504  for receiving the clip  315  that is integrally formed with or connected to the intake pipe  302  is also shown. As shown in  FIGS. 10 and 11 , the slot  504  is positioned such that the inlet end  312  of the intake pipe  302  is positioned to receive intake air through at least one of the ventilation openings  520 . As such, the ventilation openings  520  provide intake air to both the radiator and fan assembly  170  as well as the intake air system  300 . As shown in  FIG. 13 , The inlet end  312  of the intake pipe  302  is positioned adjacent a rear lateral portion of the seat  507 . In this position, the inlet end of the intake pipe  302  is positioned rearward of the front wheels  102 , and preferably above one of the rear wheels  103 . As also shown, the inlet end  312  of the intake pipe  302  curves to the right side of the ATV, toward a right one of the rear fenders  516 . In this manner, in the illustrated preferred embodiment, the air intake pipe  302  draws air from substantially only one of the ventilation openings  520 , which is on the right side of the ATV, as shown in FIG.  13 . 
     It is also contemplated that the intake pipe  302  may curve to the left, so as to draw air substantially from the left side of the ATV, or may be disposed proximate the center of the ATV, between the rear fenders  516 , so as to draw air from both ventilation openings  520 . Furthermore, the intake pipe  302  may be configured such that an intake opening  360  provided by the intake pipe  302  is arranged in a generally forwardly facing direction so as to confront connecting wall  502 . In this manner, there is a decreased likelihood that foreign objects or water may enter the intake opening  360 . 
     Alternatively, the intake pipe  302  may be configured such that the intake opening  360  faces toward a rear of the ATV, or laterally toward the center of the ATV. Obviously, foreign objects and water are substantially prevented from entering the intake opening  360  in any of these arrangements due to the orientation of the intake opening  360  relative to the direction of air flow (and perhaps water flow, if water enters the openings  520 ) through the channels  590  toward the radiator and fan assembly  170 . 
     Another contemplated embodiment is shown in FIG.  13 B. As shown, the seat  507  includes a seat frame  800 . The seat frame  800  serves to provide rigidity to the seat  507  and allow padding materials to be mounted thereto. Additionally, the seat frame  800  may form a hollow enclosure  802  at a rear portion  804  of the seat  507 . As also shown, the intake pipe  302  connects to the enclosure  802 . It is contemplated that an air intake opening, indicated at  806 , may be formed, for example, within the seat  507  itself or between the rear portion  804  of the seat  507  and the connecting wall  502 . In this manner, air may pass through the intake opening  806 , through an aperture  808  in the enclosure  802 , and to the intake pipe  302 . 
     The enclosure  802  may serve to facilitate the attenuation of noise and vibration emitted by the intake pipe  302 . It is also contemplated that attenuation features, such as ribs, may be formed on an interior of the enclosure  802  to further attenuate noise and vibration. 
     Furthermore, it is contemplated that the enclosure  802  may be used either in lieu of or in addition to the air box  301 . 
       FIG. 14  is a schematic diagram illustrating one advantage to the arrangement shown in the preferred embodiments illustrated herein. In  FIG. 14 , the ventilation openings  520  and/or the inlet end  312  of the intake pipe  302  are/is positioned at a height that is greater than the depth D wake  of the wave and is preferably greater than the predetermined depth D nominal  of the water. In addition, the inlet end  312  is positioned on the vehicle so as to avoid entry of water due to encountering a water wave W at the front of the ATV  500 , wherein the water wave W has a depth D max  greater than the predetermined depth D nominal . Moreover, positioning of the inlet end  312  of the intake pipe  302  as indicated in  FIG. 14  takes advantage of the fact that the depth D wake  of the water behind the wave W is less than the depth of the water D nominal  in front of the wave W due to the wake created by the ATV  500 . 
     While preferred embodiments of the invention have been shown and described, it is evident that variations and modifications are possible that are within the spirit and scope of the preferred embodiments described herein.