Patent Publication Number: US-2022212754-A1

Title: Multi-Piece Tunnel For A Snow Vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/134,873, filed on Jan. 7, 2021. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a tunnel that partially covers a track of a tracked vehicle and, more particularly, to a tapered short tunnel for use on a tracked vehicle, such as a snowmobile. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Tracked vehicles, such as snowmobiles or snow bikes, generally include one front ski or a pair of front skis for steering and a rear endless track for driving or propelling the snowmobile. A chassis, or body, of the snowmobile includes a tunnel that is positioned over the track to support a seat and prevent snow from hitting the snowmobile occupants. 
     The tunnel is commonly formed of metal and is therefore a significant cause of weight for the vehicle. Snowmobiles can traverse various terrain and conditions. In deep powder snow that occurs frequently on mountain terrain, it is not uncommon to be riding in several feet of powder snow. Such riding can result in forming a deep trench or trenching in the snow because of the track. Such trenching can cause the rear of the snowmobile to fall into the trench and get stuck. Reducing the weight of the snow vehicle increase the ease in which the operator can free the vehicle from the stuck position. 
     Further, reducing the weight reduces fuel consumption and increase maneuverability. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In one aspect of the disclosure, a tunnel is configured to cover at least a portion of an endless track of a snow vehicle. The tunnel has a top plate extending longitudinally. The top plate has a first flange extending from a first side edge and a second side flange extending from a second side edge. The tunnel further has a first sidewall coupled to the first flange. The first sidewall extends generally parallel with the first flange. A second sidewall is coupled to the second flange. The second sidewall extends generally parallel with the second flange. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a perspective view of an exemplary snowmobile in accordance with the present disclosure; 
         FIG. 2  is another perspective view of the snowmobile of  FIG. 1 ; 
         FIG. 3  is a front view of the snowmobile of  FIG. 1 ; 
         FIG. 4  is a rear view of the snowmobile of  FIG. 1 ; 
         FIG. 5  is a top view of the snowmobile of  FIG. 1 ; 
         FIG. 6  is an exploded view of the snowmobile of  FIG. 1 ; 
         FIG. 7  is a left side perspective view of the tunnel coupled to structural members. 
         FIG. 8  is a right side perspective view of the tunnel of  FIG. 7 . 
         FIG. 9  is a partially exploded bottom view of the tunnel of  FIG. 7 . 
         FIG. 10  is a longitudinal cross-sectional view of the tunnel of  FIG. 7 . 
         FIG. 11  is a lateral cross-sectional view of the tunnel of  FIG. 7 . 
         FIG. 12  is an enlarged cross-sectional view of a portion of  FIG. 11 . 
         FIG. 13  is right side view of a longitudinal cross section. 
         FIG. 14  is a partially exploded view of the running boards relative to the tunnel. 
         FIG. 15  is left side view of the mounting brackets for the running board. 
         FIG. 16  is a partial underside perspective view of the tunnel. 
         FIG. 17  is an enlarged underside perspective view of the distal end of the tunnel. 
         FIG. 18  is a top partially explodes view of the tunnel and the bumper. 
         FIG. 19  is a perspective view of the bearing carrier  210 . 
         FIG. 20  is an enlarged left side view of the bearing carrier within the tunnel 
         FIG. 21  is a partial underside perspective view showing the cooler opening of the top plate. 
         FIG. 22  is a bottom view of the coolers disposed in a top plate. 
         FIG. 23  is a partially exploded view of the coolers expanded from the top plate. 
         FIG. 24  is a partially exploded view of the engine mount coupled to the first sidewall. 
         FIG. 25  is a partially exploded view of the engine mount relative to the sidewall. 
         FIG. 26  is a left side view of the engine mount of  FIGS. 25 and 26 . 
         FIG. 27  is a right side perspective view of the engine mount of  FIGS. 25-27 . 
         FIG. 28A  is a right side view of the tunnel and chassis with the flange extending from the rearward portion behind the rear torque arm mount to in front of the crankshaft. 
         FIG. 28B  is a perspective view of the right sidewall showing the right flange. 
         FIG. 28C  is a left side perspective front view of the tunnel showing the flange and the cooler  2910 . 
         FIG. 29A  is an underside view of the tunnel of  FIG. 28C . 
         FIG. 29B  is a cutaway view looking toward the front of the cooler. 
         FIG. 29C  is a perspective inside view of the cooler. 
         FIG. 29D  is a perspective outside view of the cooler of  FIG. 29C . 
         FIG. 29E  is a side view of the cooler of  FIGS. 29A-29D . 
         FIG. 30  is a side cross-sectional view of the second sidewall  122 . 
         FIG. 31A  is a perspective view of the chain case. 
         FIG. 31B  is a cross-sectional view of the chain case mounted to the first sidewall  120  or the second sidewall  122 . 
         FIG. 32A  is a cross-sectional view of a second example of a tunnel construction. 
         FIG. 32B  is a cross-sectional view of a third example of a tunnel construction. 
         FIG. 33A  is a cross-sectional view of the tunnel having a portion of the cooler  3310  integrally molded therein. 
         FIG. 33B  is a cross-sectional view showing a first portion of the cooler  3310  integrally molded and a second portion  3320  that is coupled to the first portion  3310 . 
         FIG. 34A  is a top view of an alternate example of a top plate  114 . 
         FIG. 34B  is a cross-sectional view of the top plate of  FIG. 34A . 
         FIG. 34C  is a top view of a third example of a top plate  114 . 
         FIG. 35  is a cross-sectional view of a fluid containment system formed with at least one of the top plate  114 , the first sidewall  120  or the second sidewall  122 . 
         FIG. 36A  is a cross-sectional view of a mount for coupling a brake caliper of  FIG. 36A  thereto. 
         FIG. 36B  is a mount for mounting an air box thereto. 
         FIG. 36C  is a mount for mounting a muffler thereto. 
         FIG. 36D  is a mount for mounting an oil pump  3636  thereto. 
         FIG. 36E  is a mount for mounting a fuel tank  3636  thereto. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     With initial reference to  FIGS. 1-6 , an exemplary vehicle in accordance with the present disclosure is illustrated. Although the vehicle is illustrated as a snowmobile  10 , numerous aspects of the present disclosure may be included with any other suitable vehicle as well. The snowmobile  10  may be any suitable type of snowmobile, such as any suitable trail snowmobile, sport trail snowmobile, touring snowmobile, performance snowmobile, utility snowmobile (such as any snowmobile suitable for search and/or rescue, law enforcement, military operations, etc.), crossover snowmobile, mountain snowmobile, youth snowmobile, etc. 
     The snowmobile  10  generally includes a front end  12  and a rear end  14 . At the front end  12  is a front suspension  16 . At the rear end  14  is a rear suspension  18 . The front suspension  16  and the rear suspension  18  support a chassis  20 . 
     The front suspension  16  includes shock absorbers  22 , each one of which is connected to a ski  24 . The shock absorbers  22  may be any dampening devices suitable for absorbing shock resulting from the skis  24  passing over uneven terrain. The skis  24  are steered in part by a suitable steering device, such as handlebars  26 . The rear suspension comprises a torque arm  29 , 
     Coupled to the rear suspension  18  is a belt or track  30 , which is endless or continuous. Rotation of the track  30  propels the snowmobile  10 . The track  30  is circulated through a tunnel  32  defined at least in part by the chassis  20  and is positioned by the torque arm  29  that id coupled to the tunnel as will be described in more detail below. The tunnel  32  is tapered at the rear end  14 , as described in detail herein. A flap  34  is mounted at the rear end  14  and blocks snow and other debris from being “kicked-up” by the track  30 . 
     Mounted to the chassis  20  and atop the tunnel  32  is a seat  40  for the operator of the snowmobile  10 . On both sides of the chassis  20  or tunnel  32  are running boards  42 , upon which the operator may rest his or her feet when seated on the seat  40 . The seat  40  is positioned to allow the driver to grasp the handlebars  26  for steering the snowmobile  10 . The handlebars  26  are mounted to a steering rod  28 , which protrudes out from within the center console  44 . At the center console  44  is a fuel cap  46  of a fuel tank  48 . 
     At the front end  12  of the snowmobile  10  is a hood assembly  50 , which is mounted on top of a nose pan  68 . Mounted to the hood assembly  50  and protruding from a forward most end thereof, is a front bumper  52 . The hood assembly  50  houses headlights  54 . An optional windshield  56  is connected to an uppermost portion of the hood assembly  50 . Associated with the hood assembly  50  is a display  58  viewable by the operator when seated on the seat  40 . Mounted to opposite sides of the hood assembly are body panels  60 , which are advantageously interchangeable. 
     With particular reference to  FIG. 6 , the snowmobile  10  further includes an engine assembly  70 . The engine assembly  70  generates power for driving the track  30 . The engine assembly  70  may include any suitable engine, such as an electric, 2-stroke, and 4-stroke engine. Coupled to the engine assembly  70  is an exhaust assembly  72 . Any suitable exhaust assembly may be used. Oil for the engine assembly  70  is stored in an oil tank assembly  74 , which may be arranged proximate to the seat  40 . 
     The snowmobile  10  further includes any suitable control module  64 . The control module  64  may be arranged at any suitable location, such as within the hood assembly  50 , beneath the center console  44 , or within any suitable control mounted to the handlebars  26 . The term “control module” may be replaced with the term “circuit.” The term “control module” may refer to, be part of, or include processor hardware (shared, dedicated, or group) that executes code and memory hardware (shared, dedicated, or group) that stores code executed by the processor hardware. The code is configured to provide the features of the control module described herein. The term memory hardware is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave). The term computer-readable medium is therefore considered tangible and non-transitory. Non-limiting examples of a non-transitory computer-readable medium are nonvolatile memory devices (such as a flash memory device, an erasable programmable read-only memory device, or a mask read-only memory device), volatile memory devices (such as a static random access memory device or a dynamic random access memory device), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc). 
     Referring to  FIGS. 7-27 , the tunnel  32  is illustrated in various perspective views. In the following description, the tunnel  32  is a multi-piece tunnel that is formed from but not limited to sheet molded composite such as carbon fiber. Of course, other types of materials may be used. By allowing materials that may be molded, the wall thickness may be varied in locations that are desired to be reinforced. Overmolding of dissimilar material components, for example metal, within the composite material forming the tunnel is also possible. The tunnel  32  extends along a longitudinal axis  108  from a first proximal end  110  to a second distal end  112 . The tunnel  32  has an overall length of about 1733 mm, with a range of lengths between about 1733 mm to about 2100 mm. The tunnel  32  includes an upper substantially planar or top plate  114  bounded by the first proximal end  110  and the opposed second distal end  112 . A first side flange  116  and an opposed second side flange  118 . Extending at about 90° from the top plate  114  is a first tapered sidewall  120 . Extending vertically from the second sidewall  118  is a second tapered sidewall  122 . A slight angle of about plus or minus 3 degrees is also possible. In one example, the walls are disposed outward several degrees. The tunnel  32  is shaped to substantially cover the track  30  and support the seat  40  and fuel tank  48 . The top plate  114  and the sidewalls  120  and  122  can be formed separately and attached to one another, such as by welding, riveting, fasteners, adhesives, etc. Alternatively, the tunnel  32  can be bent or shaped to form an integral one-piece construct. 
     As is best illustrated in the cross-sectional views of  FIGS. 11 and 12 , the first sidewall  120  may have a first offset portion  124  and the second sidewall  122  may have a second offset portion  126 . In general, the first sidewall  120  and the second sidewall  122  are generally planar. The first offset portion  124  and the second offset portion  126  are offset a distance D 1  inward relative to the vehicle to receive the thickness of the first side flange  116  and the second side flange  118  respectively. In this example, the outer surfaces of the first side flange  116  and the second side flange  118  are coplanar with the first sidewall  120  and the second sidewall  122 , respectively. 
     In this example, the first side flange  116  and the second side flange  118  are coupled to the respective first offset portion  124  and the second offset portion  126  with a rivet  128 . Of course, other types of fasteners may be used. Likewise, the fasteners may be eliminated with the use of adhesive  130 , a portion of which is illustrated. The adhesive  130  may be disposed within a channel  132  that is formed between the respective offset portion  124 ,  126  and the respective first side flange  116  and the second side flange  118 . A spacer  134  extends laterally from one of the first side flange  116 , second side flange  118 , the first offset portion  124  and the second offset portion  126 . In this example, the spacer  134  extend lateral (relative to the vehicle) outward from the first offset portion  124  and the second offset portion  126 . It should be noted that one or both offset portions  124 ,  126  may be formed on the edge as well. Of course, more than two spacers  134  may be used. The spacers  134  allow a sufficient amount of adhesive to be used to join the first side flange  116  and the first sidewall  120  as well as the second side flange  118  and the second sidewall  122 . The first sidewall  120  and the second sidewall  122  may have a primary thickness such as 2 mm. However, curved portions and reinforcement areas may have a second thickness such as 3 mm. In this example, the first sidewall  120  and the second sidewall  122  have a thickness T 1  such as 2 mm (primary or nominal thickness) while the side flanges  116 ,  118  have a thickness T 2  such as 3 mm (secondary thickness). The total secondary thickness area of the tunnel  32  is less than the area of primary thickness, in this example. In other examples, the thicknesses T 1  and T 2  can be reversed. 
     The tunnel  32  may also be used for coupling structural members  140  thereto. The structural members  140  may be mounted to a reinforcement area  142  on the sidewalls  120 . This is best illustrated in  FIG. 10 . The reinforcement area  142  may be an area of secondary thickness such as 3 mm as opposed to the primary thickness of the sidewalls  120 ,  122 . 
     The structural members  140  of the chassis  20  may be joined at a joiner  144 . The joiner  144  may also be coupled to forward structural members  146 . Front cross members are used to couple to the forward structural members  146  and to the front end  12  of the tunnel  32 . As will be described in further detail below, the front portions of the sidewalls  120 ,  122  and the intersection of the front cross members  148  may have an engine mount disposed therein. 
     The first sidewall  120  has a lower flange  152  and the second sidewall  122  has a lower flange  154 . The lower flanges  152 ,  154  extend laterally outward from the respective sidewalls  120 ,  122 . The lower flanges  152 ,  154  may be formed of the same material and molded simultaneously with the sidewalls  120 ,  122 . The lower flanges  152 ,  154  may be the secondary thickness such as 3 mm. The running boards  42  are attached to the lower flanges  152 ,  154  of the respective sidewalls  120 ,  122 . In this example, the running boards  142  are disposed on top of the lower flanges  152 ,  154 . Fasteners, such as rivets  156 , are used to secure the running boards  42  to the respective lower flanges  152 ,  154 . 
     The running boards  42  may also be attached to the first side flange  116  and the second side flange  118  at the running board mounting position  158 . The running board mounting position  158  of the flanges  116 ,  118  may be the secondary thickness there around. The running board mounting position  158  may extend into the first offset  124  and the second offset  126 . That is, the running board mounting position  158  may include the fastener  128  that extends through the first offset portion  124  and the respective first side flange  116  while the second offset portion  126  and the second side flange  118  may be joined together with a fastener  128 . The first sidewall  120  and the second sidewall  122  may each contain a downwardly extending mount  162 ,  164 . The downwardly extending mounts  162 ,  164  may receive running board brackets  166 ,  168  that are disposed in mounting areas  170 ,  172 , respectively. 
     A bumper  180  is secured to the tunnel  32 . In this example, the bumper  180  is U-shaped. The U-shaped bumper has a pair of first portions  180 A that are forwardmost in the bumper  180 . The forwardmost portions are coupled to an angled portion  180 B which, in turn, is coupled to a lateral portion  180 C. A lateral portion  180 C extends over the flap  34 . The distal end  14  of the tunnel  32  may have recess  182  for receiving the flap  34 . The recess  182  extends downward relative to vehicle and receives at least a portion of the flap  34 . The bumper  180  may be formed of a singular piece or multiple pieces. The bumper  180  is coupled to the tunnel  32  with fasteners  184 . 
     A lateral wall  186  extends laterally across the width of the tunnel  32  and, in particular, the top plate  114  of the tunnel  32 . It should be noted that the flap  34  may include a rear brake light and running light. The lateral wall  186  may be the primary thickness such as 2 mm or may be the secondary thickness of the tunnel  32  to provide extra rigidity. A bumper mount  188  extending in an upward direction relative to the vehicle may receive fasteners  184  for securing at least a portion of the bumper  180 . 
     The mounts  162 ,  164  may include torque arm mounts  190 ,  192 . The torque arm mounts  190 ,  192  may be mounted at the rear mounting area  194 ,  196 , respectively which may be the secondary thickness of the molded tunnel material. The torque arm mounts  190 ,  192  may be used for receiving a torque arm that is ultimately coupled to the remaining portion of the suspension that couples the track to the vehicle. The torque arm is illustrated as reference numeral  29  in  FIG. 1 . A front torque arm mounting area  198  is disposed toward the front of the vehicle. The immediate area therearound may be the second thickness greater than the first thickness. 
     The front of the snow vehicle  10  has a first side brace portion  202  and a second side brace portion  204 . The side brace portions  202 ,  204  are integrally formed with the front first sidewall  120  and the second sidewall  122 . In prior snow vehicles the side braces are completely separate pieces. 
     As is best illustrated in  FIGS. 8, 9, 10, 13 and 20 , a bearing carrier  210  may be integral formed in a front portion of the second sidewall  122 . The bearing carrier  210  may be formed of a different material than that of the sidewalls. For example, the bearing carrier  210  may be formed of metal. The metal of the barrier  210  may have a lower coefficient expansion than the material of the sidewalls and the top plate. The bearing carrier  210  has a first bearing receiver  212 A and a second bearing receiver  212 B. A bearing  214 A and a bearing  214 B are located in respective bearing receivers  212 A,  212 B. 
     The bearing carrier  210  has one or more molding flanges  216 . In this example, the molding flanges  216  extend around the periphery of the bearing carrier  210 . The molding flanges  216  have molding holes  218  disposed therein. The molding holes  218  allow molding material to be molded. That is, the bearing carrier  210  may be overmolded into the second sidewall  122 . The molding holes  218  allow the molding material to flow therein to secure the bearing carrier  210  within the second sidewall  122 . Thus, the thickness of the composite material together with the thickness of the bearing carrier  210  and the molding flanges  216  are greater than the first primary thickness and the second thickness of the composite material. 
     The bearing  214 A may receive the jackshaft of the engine. The bearing  214 B may be used to receive the rotating shaft of the driveshaft. 
     Retainers  220 A,  220 B may respectively be used within the bearing receiver  212 A,  212 B, respectively, to retain the bearings  214 A,  214 B therein. As illustrated, the retainers  220 A,  220 B are C-clips. 
     Referring specifically now to  FIGS. 21-23 , the top plate  114  of the tunnel  32  has a cooler opening  228 . The cooler opening  228 , in this example, is rectangular. The cooler opening  228  is used to receive a cooler  230 . In this example, a first cooler  230 A and a second cooler  230 B are set forth. The coolers  230 A,  230 B, together with the cooler opening  228 , is rectangular. The cooler opening  228  may have a cooler opening reinforcement area  232  there around or at least partially there around. The cooler opening reinforcement area  232  may be an area with a thickness such as the secondary thickness such as 3 mm. Fasteners  234  may be used to couple end flanges  236  of the coolers  230 A,  230 B to the cooler opening reinforcement area  232 . 
     A pad  238 A and pad  238 B may be located on the top surface of the top plate  114  of the tunnel  32  to protect the coolers  230 A,  230 B. The pads  238 A and  238 B may be formed of foam. 
     The front end  12  of the first sidewall  120  may be reinforced to receive an engine mount  250 . The first sidewall  120  has a pocket  252 . The pocket  252  laterally extends into the wall  120 . The pocket  252  receives a tab  254  that has a wide portion  254 A and a narrow portion  254 B. A narrow portion  252 B corresponds to the narrow portion  254 B and a wide portion  252 A of the pocket  252  corresponds to the wide portion  254 A of the tab  254 . A locator  256  of the engine mount  250  is located within a locator pocket  256  when assembled. The engine mount  250  may be made of a resilient material that is different than the material used to the form the sidewalls. The engine mount  250  may thus be used to damp vibration of the engine. The composite material may of the tunnel together with engine mounts may significantly reduce dampen vibration in the vehicle. Fasteners may be received within the holes  262  for mounting the engine to the engine mounts  250 . Ribs  264  extend upward and downward from the engine mount  250  relative to vehicle. The ribs  264  may help retain the engine mount  250  within the pocket  252 . Fasteners received within the holes  262  disposed on either side of the engine prevent the engine mount  250  from moving laterally outward from the pocket  252 . It should be noted that although only one engine mount  250  is illustrated, more than one engine mount such as another engine mount on the other side of the vehicle may also be provided. 
     By molding all or some of the components of the tunnel  32 , various portions of strengthened composite material may be formed. Unidirectional tape may be molded into certain areas to increase the strength in a high stress area. In  FIG. 25 , the sidewall  120  reinforce ribs or areas  280 . The reinforced ribs or areas  280  may extend vertical or angularly relative to the vehicle. The reinforced areas  280  may surround areas of high stress. Both the sidewalls  120 ,  122  as well as the top plate  114  may have reinforced areas  280 . The reinforced areas may be a uniform thickness such as 3 mm while the primary thickness of the composite components is different such as 2 mm. The reinforced areas  280  may be positioned around where fasteners are used to secure other components to the vehicle. The reinforced areas  280  are selectively used so that the bulk of the area of the top plate  114  and the sidewalls  120 ,  122  are of the lesser primary thickness. This eliminates the use of doubling plates as was common in previously known tunnel designs. The reinforced areas  280  may extend to the sidewalls around the bearing retainer as well. 
     To form the tunnel  32 , one or more of the top plate  114 , the first sidewall  120  and the second sidewall  122  are molded of composite material. Each piece can be separately molded. The top plate has a first flange and a second flange extending from opposite edges of the top plate. A first adhesive channel is formed between the first sidewall and the first flange and a second adhesive channel is formed between a second flange and the second sidewall. Adhesive is applied in the in the first adhesive channel and the second adhesive channel. The first sidewall is affixed to the first flange and the second sidewall to the second flange from bonding of the adhesive. Fasteners may also be used to strengthen the connection between the flanges and the sidewalls. Fasteners fasten the first sidewall to the first flange and the second sidewall to the second flange. 
     Referring now  FIG. 28A , the right side of the tunnel is illustrated. In this example, the use of the lower flanges that extend from the rear of the vehicle from behind the lower suspension mount  164  is set forth. The right lower flange  154  extends forward of the jackshaft  2810  of the engine assembly  70 . As illustrated in  FIGS. 25-27 , an engine mount is illustrated at the end of the left side and left sidewalls  120 ,  122 . The first sidewall  120  and the second sidewall  122  extend forward of the engine and in particularly, the jackshaft  2810  and reinforcement areas that are thicker than the nominal wall thickness. The longitudinally extending flange  154  is best illustrated in  FIG. 28B . The right lower flange  154  is shown from a partial underside perspective view extending forward all the way to a position forward of the longitudinal position of the crankshaft  2810 .  FIG. 28C  shows the left side and left lower flange  152  that extends rearward of the lower suspension mount  162  and longitudinally forward of the position of the crankshaft  2810 . 
     Referring now to  FIGS. 28C and 29A-29E , the position of a generally vertically oriented cooler  2910  is set forth. The cooler  2910  is positioned between the first sidewall  120  and the second sidewall  122 . Fasteners  2912  illustrated in  FIG. 28C  extend through a reinforced portion  2914  of the sidewall  120 . The reinforced portion  2914  is thicker than the nominal thickness of the sidewall. Fasteners receivers  2916 , illustrated best in  FIGS. 29C and 29E , are used to receive the fasteners  2912 . The cooler  2910  has a cover side  2918  and a cooling side  2920  that is used to contact the snow within the tunnel and therefore cool the engine coolant that passes through the cooler  2910 . A flange  2922  illustrated in  FIG. 29D  is used to couple to the floor pan  2924  of the chassis  20 . Reinforced portions are also disposed on the right side of the vehicle for receiving fasteners and coupling the cooler  2910  to the second sidewall  122 . An upper flange  2930  disposed on the cooler  2910  is used for coupling the upper portion of the cooler  2910  to the top plate  114 . 
     Referring now to  FIG. 30 , the second sidewall  122  is illustrated in cross-section. The right sidewall  122  and a close up of the right lower flange  154  is illustrated. The flange  154  is formed as a perpendicular extension from the sidewall  122 . In this example, the sidewall  122  has a thickness T 1  as described above. The thickness T 1  is referred to as either the primary or nominal thickness of the sidewall  122 . The right lower flange  154  has a thickness T 3  that may be the same as the thickness T 2  or different therefrom. The thickness T 3  is formed by a first radius  3010  which has a large diameter and a second radius  3012  which has a smaller diameter. Of course, the thicknesses T 1 , T 2  and T 3  may all be uniform in thickness. The radius  3010  is on the inside of the 90° angle that forms the right lower flange  154  from the sidewall  122 . The sidewall portion  122  is generally perpendicular near the flange  154 . The outer wall of the angle between the sidewall  122  and the flange  154  is smaller. This allows the thickness T 3  to be formed different than the thickness T 1  of the sidewall  122 . It should be noted that the sidewall  120  and the left lower flange  152  may be formed in a similar manner. Further, other components may also extend from the sidewalls  120 ,  122  or the top plate  114 . These may include different surfaces or components than the flange. Because the sidewalls  120 ,  122  and the top plate  114  are molded, different thickness may be formed in different areas. 
     Referring now to  FIGS. 31A and 31B , a chain case  3110  is illustrated partially integrally molded with one of the sidewalls as a fluid containment system, in this example, the sidewall  122 , as an alternative embodiment. The sidewall  122  also forms one side of the chain case. The chain case has laterally extending walls  3112 , a cover  3114  is fastened to the laterally extending walls  112  using fasteners  3116  that are received in the fastener receivers  3118  illustrated best in  FIG. 31A . The chain case  3110  is used to hold chain case lubrication fluid therein. The chain case  3110  may also include a plurality of sprockets or gears (not illustrated) for rotatably coupling to the chain (also not illustrated). 
     Referring now to  FIG. 32A , an alternate tunnel  32 ′ is illustrated. In this example, the tunnel, instead of being three main components as illustrated above, includes two components  3210 A,  3210 B. Each component forms a right angle. Each right angle forms one of the first sidewall  120  or the second sidewall  122  and a first part  3212  or a second part  3214  of the top plate  114 ′. 
     In the example illustrated in  FIG. 32B , the top plate  114 ″ is formed in the first portion  3210 A′. The sidewall  122  is formed in the second portion  3210 B′. A flange  118  may be formed in a similar manner to that described above for joining the sidewall  122  to the top plate  114 ″. 
     In the example set forth in  FIGS. 32A and 32B , the portions  3210 A′ and  3210 B′ and  3210 A and  3210 B are formed of molded material. This allows various shapes to be formed. 
     Referring now to  FIG. 33A , top plate  114  is illustrated with part of the first cooler  230 A integrally molded therein. In this example, the first cooler  230 A has a first portion  3310  integrally molded into the top plate  114 . 
     In  FIG. 33B , the first portion  3310  is illustrated integrally molded within the top plate  114 . A second portion  3320  that is coupled to the top portion  3310  is coupled to the first portion  3310 . The second portion of the cooler  3320  may extend within the opening within the top plate  114 . 
     Referring now to  FIGS. 34A and 34B , the top plate  114  is illustrated having an integrally formed fluid channels  3410 . The fluid channels may lead to a component such as the coolers  230 A,  230 B or the second portion  3320  of the cooler illustrated in  FIG. 33B . The fluid channels  3410  may have a fitting  3412  extending therefrom. The fittings  3412  allow a host, for example, couple to the engine assembly. Typically, an inlet fluid channel and an outlet fluid channel may be provided. The fluid channels  3410  provided in  FIGS. 34A and 34B  are used for communicating fluid between the engine assembly and the cooler  230 A,  230 B. However, other uses for the fluid channels with other fluids may be provided. 
     Referring now to  FIG. 34C , the top plate  114  is illustrated having a fluid component integrally molded or partially integrally molded therein. The fluid component  3420  may also be mounted to the top plate  114  as a separate component. However, fluid channels  3422  communicate fluid through the top plate  114  to the engine or other suitable component. The fluid component  3420  may be located at or rearward of the suspension mounts  162 ,  164  and forward of the rear pads  238 A,  238 B (in  FIGS. 21-23 ). 
     Referring now to  FIG. 35 , as mentioned briefly in reference to  FIG. 34C , a fluid component  3420  may be provided. One example is a fluid containment system  3510  such as a fluid containment system may be partially or integrally formed with the first sidewall  120 , the second sidewall  122  or the top plate  124 . The fluid containment system  3510  may include walls  3512 ,  3514  that extend from one of the first sidewall  120 , the second sidewall  122  or the top plate  114 . The fluid containment system  3510  may also be lined with an impenetrable material like the liner  3640  described below. Examples of a fluid containment system include an oil reservoir, a coolant tank, a heat exchanger, a chain case or a fuel tank. 
     Referring now to  FIGS. 36A-36E , the sidewalls  120 ,  122  or the top plate  114  may have a mount  3610  coupled thereto. The mount  3610  has a thickness T 5  that is larger than the nominal thickness T 1  of the top plate  114 , the first sidewall  120  or the second sidewall  122 . The mount  3610  has a fastener opening  3612  for receiving a fastener  3614 . In  FIG. 36A , the mount  3610  is used for mounting a brake caliper  3630  thereto. The fastener  3614  couples to the wall or outer housing of the brake caliper  3630 . 
     Referring now to  FIG. 36B , the mount  3610  is used for mounting an air box  3632  to the mount  3610 . The air box  3632  provides intake air to the engine. 
     Referring now to  FIG. 36C , the mount  3610  may be used for coupling a muffler  3634  thereto. The muffler  3634  may also be referred to as a silencer. 
     Referring now to  FIG. 36D , the mount  3610  may also be used for coupling an oil pump  3636  thereto. 
     Referring now to  FIG. 36E , the mount  3610  may also be used for coupling a fuel tank  3638  thereto. A liner  3640  may be coupled therein so that the tunnel surface or sidewalls do not directly contact the fuel. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.