Abstract:
A hydrogen ventilation duct includes tubes for communication between a motor room as a space beneath a hood and a space inside a gutter. The gutter includes a vent communicating with the outside. Hydrogen staying in the motor room is released naturally through the tubes into the atmosphere.

Description:
FIELD OF THE INVENTION 
     This invention relates to a fuel-cell-powered vehicle and, more particularly, to a hydrogen ventilation duct for emitting hydrogen in a space underneath the hood of the vehicle in natural ventilation. 
     BACKGROUND OF THE INVENTION 
     Automobiles include fuel-cell-powered vehicles which are propelled with motors driven by electricity generated in fuel cells supplied with hydrogen and oxygen (air). Some fuel-cell vehicles have drive motors disposed in spaces beneath hoods at the front bodies (hereinafter referred to as “motor rooms”), fuel cells disposed beneath floor plates, and intake ducts extended from the fuel cells to the motor rooms. 
     The intake ducts take in air from the motor rooms, guiding the air to the fuel cells, and thereby providing ventilation of the fuel cells. 
     In a fuel-cell vehicle with such an intake duct, if the fuel cells leak hydrogen for some reason when stopping the generation of electricity, the leaked hydrogen can pass through the intake duct and flow into the motor room. Most of the hydrogen entering the motor room will flow out through the gaps between the front fenders and the hood, for example, into the atmosphere. Part of the hydrogen, however, can stay below the hood. 
     In order to emit hydrogen staying under the hood into the atmosphere, a ventilation duct may be provided in the hood of the fuel-cell vehicle. The ventilation duct provided in the hood allows natural ventilation to remove hydrogen staying underneath the hood. 
     However, the provision of the ventilation duct in the hood can cause entering of rainwater or wash water, for example, into the motor room through the ventilation duct. The entering rainwater or wash water may reach various kinds of equipment such as a motor controller provided in the motor room. 
     It is thus desirable to provide natural ventilation for emitting hydrogen staying under the hood while preventing the entering of rainwater or wash water into the motor room. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a hydrogen ventilation duct mountable to a hood of a fuel-cell-powered vehicle, which comprises: a gutter with a substantially rectangular depression configured to be disposed between an outer panel and an inner frame which constitutes the hood; at least one tube provided in a base of the gutter so as to establish communication between a space below the hood and a space inside the gutter; a cover integrally formed with the upper end of the gutter so as to be positioned above the tube, the cover having a vent for communication between the space inside the gutter and ambient air; and at least one guide plate integrally provided to the rear surface of the cover in a position between the vent of the cover and the tube, the guide plate extending at the lower end thereof to a level lower than the upper end of the tube; wherein, hydrogen in the space below the hood is guided through the tube into the space inside the gutter, and the hydrogen in the space inside the gutter is guided from opposite sides of the guide plate to the vent. 
     Thus, establishing the communication between the space below the hood and the space inside the gutter using the tube and the communication between the space inside the gutter and the vent, and disposing the vent above the outer panel allow hydrogen staying under the hood to be guided through the tube into the space inside the gutter and then emitted through the vent into the atmosphere. Further, the disposition of the guide plate in the space inside the gutter between the vent and the tube results in rainwater or wash water entering the space inside the gutter from the vent guided by the guide plate to flow around the tube. The rainwater or wash water is thus guided to the gutter without entering the tube and is thus prevented from entering the motor room in which various kinds of equipment are disposed. 
     The guide plate is curved to protrude toward the tube, so that hydrogen entering the space inside the gutter from the tube is smoothly guided by the guide plate to the vent. 
     A drain pipe is connectable to the gutter, so that water collected in the gutter is:discharged through the drain pipe. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Certain preferred.embodiments of the present invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 is a partial perspective view of a fuel-cell-powered vehicle with a hydrogen ventilation duct according to the present invention; 
     FIG. 2 is a perspective cutaway view of the hydrogen ventilation duct of the fuel-cell-powered vehicle according to the present invention; 
     FIG. 3 is an enlarged cross-sectional view taken along line  3 — 3  in FIG. 1; 
     FIG. 4 is an enlarged cross-sectional view taken along line  4 — 4  in FIG. 1; 
     FIG. 5 is an enlarged cross-sectional view taken along line  5 — 5  in FIG. 1; 
     FIGS. 6A and 6B are diagrams illustrating the flows of hydrogen exiting through the hydrogen ventilation duct of the present invention; 
     FIGS. 7A and 7B are diagrams illustrating the flows of water entering the hydrogen ventilation duct of the present invention; and 
     FIG. 8 is a diagram illustrating the drain of water entering the hydrogen ventilation duct of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. 
     Referring to FIG. 1, a fuel-cell-powered vehicle  10  has left and right front pillars  13 ,  14  extended respectively from the rear upper ends of left and right front fenders  11 ,  12 , a windshield  15  extended between the left and right front pillars  13 ,  14 , a front bumper  16  provided at the front ends of the left and right front fenders  11 ,  12 , a hood  17  extended across the space formed by the left and right front fenders  11 ,  12 , windshield  15  and front bumper  16 , and a hydrogen ventilation duct  20  provided in the vicinity of a rear end  17   a  of the hood  17 . 
     FIG. 2 illustrates the hydrogen ventilation duct  20 . The hydrogen ventilation duct  20  has a duct body  21  in a substantially rectangular shape mounted in the vicinity of the rear end  17   a  of the hood  17  and a drain tube (drain pipe)  60  extending along the hood  17  from the duct body  21  to the front end of the hood  17 . The hydrogen ventilation duct  20  is mounted to the hood  17  with left and right brackets  30 ,  31  provided at the left and right ends of the duct body  21  bolted to an inner frame. 
     The duct body  21  has a gutter  22  formed with front, rear, left and right walls  23 ,  24 ,  25  and  26  and a base  27  to have a rectangular depression, to be mounted to the hood  17 , and four tubes  35  in this embodiment provided in the base  28  of the gutter  22  at fixed intervals. Guide plates  38  are disposed between the four tubes  35  and the rear wall  24  of the gutter  22 , being opposed to the tubes  35 , respectively. The guide plates  38  are integrally formed with the rear surface of a cover  40 . The cover  40  is integrally formed with an upper end  28  of the gutter  22 . A recess  45  is formed in the middle of the base  27  of the gutter  22 . The number of the tubes  35  can be determined as desired. 
     The cover  40  has a vent  41  at its rear end portion. The vent  41  communicates with the gutter  22 . FIG. 2 shows the cover  40  divided into upper and lower covers  40   a ,  40   b  for facilitating understanding. The upper and lower covers  40   a ,  40   b  are integrally formed. 
     The guide plates  38  are curved so as to project toward the tubes  35  and recessed with respect to the vent  41 . Thus surfaces  38   c  of the guide plates  38  opposite to the tubes  35  are convex surfaces and surfaces  38   d  opposite to the vent  41  are concave surfaces. The reason why the guide plates  38  are formed to protrude toward the tubes  35  will be described with reference to FIG.  6 . The reason why the guide plates  38  are formed to be recessed with respect to the vent  41  will be described with reference to FIG.  7 . 
     The drain tube  60  is connected to the front wall  23  of the gutter  22  so as to communicate with the recess  45 . The drain tube  60  guides rainwater or wash water collected in the recess  45  to the vicinity of the front end  17   b  of the hood  17  (See FIG. 1) and discharges the water from the vicinity of the front end  17   b  of the hood  17 . 
     A plurality of tubular elastic materials  63  (See FIG. 1) are fitted onto the drain tube  60 . The tubular elastic materials  63  are disposed in the hood  17  to be held between an outer panel  18  and an inner frame  19  (See FIG.  5 ). The drain tube  60  is thus stably supported in the hood  17 . 
     As shown in FIG. 3, the outer panel  18  of the hood  17  is formed with an opening  18   a  in a substantially rectangular shape for fitting the gutter  22  therein. The inner frame  19  is formed with four circular openings,  19   a  in a direction perpendicular to the Figure sheet for inserting lower ends  35   a  of the tubes  35  therein. A hood insulator  51  is disposed below the inner frame  19 . A hood rubber seal  52  is attached to the hood insulator  51 . The hood rubber seal  52  is press-contacted with the rear surface of the inner frame  19 . 
     The gutter  22  with a rectangular depression is disposed between the outer panel  18  and the inner frame  19  of the hood  17 . An opening in the upper end  28  of the gutter  22  is positioned at the opening  18   a  of the outer panel  18 . The base  27  of the gutter  22  is positioned on the upper surface of the inner frame  19 . The tubes  35  are provided in the base  27  in a direction crossing the sheet surface at predetermined intervals. The lower ends  35   a  of the tubes  35  are respectively inserted into the openings  19   a  of the inner frame  19  so that the tubes  35  communicates with a space beneath the hood  17  (motor room)  54  and a space  55  inside the gutter  22 . Hood duct seals  56  are provided around the tubes  35 . The hood duct seals  56  abut against the inner frame  19  so that the duct body  21  blocks the openings  19   a  of the inner frame  19 . 
     The cover  40  positioned above the tubes  35  is integrally formed with the upper end  28  of the gutter  22 . A circular groove  42  is formed in a rear peripheral surface of the cover  40 . A hood duct trim  57  is held in the circular groove  42 . The hood duct trim  57  abuts against the surface of the outer panel  18  so that the cover  40  blocks the opening  18   a  of the outer panel  18 . 
     The cover  40  has the vent  41  communicating with the space  55  inside the gutter  22 . The vent  41  is positioned above the outer panel  18 . The guide plates  38  are disposed in the space  55  inside the gutter  22  between the vent  41  of the cover  40  and the tubes  35 . Upper ends  38   a  of the guide plate  38  are integrally formed with the rear surface  40   a  of the cover  40 . Lower ends  38   b  of the guide plates  38  extend downward to a level lower than the upper ends  35 b of tubes  35 . 
     The cover  40  positioned above the tubes  35  inclines upward from the front to the rear. Thus hydrogen is guided along the rear surface  40   a  of the cover  40  toward the vent  41  rearward. 
     The upper ends  35   b  of the tubes  35  incline upward to the rear in agreement with the rear surface  40   a  of the cover  40 . This allows the space between the upper ends  35   b  of the tubes  35  and the rear surface  40   a  of the cover  40  to be set small. Thus rainwater or wash water is securely prevented from entering from the upper ends  35   b  of the tubes  35 . 
     The front wall  23  and the rear wall  24  of the gutter  22  have overhangs  29 ,  29  protruding forward and backward, respectively. The opening  18   a  of the outer panel  18  is formed in a space between the overhangs  29 ,  29  and the cover  40 , and a bend  18   b  bent downward is interposed therebetween. 
     Referring to FIG. 4, the duct body  21  has the left bracket  30  extending to the left (to the right in the figure) provided at the lower end of the left wall  25  of the gutter  22 . The left bracket  30  has a female thread member  32 . The duct body  21  also has, as shown in FIG. 2, the right bracket  31  extending to the right provided at the lower end of the right wall  26  of the gutter  22 . The right bracket  31  has a female thread member  32 . Bolts  33  are screwed in the left and right female thread members  32 ,  32 , respectively, so that the left and right brackets  30 ,  31  are mounted to the inner frame  19 . 
     The tubes  35  are integrally formed with the base  27  of the gutter  22  at fixed intervals. The lower ends  35   a  of the tubes  35  are respectively inserted into the openings  19   a  of the inner frame  19  so that the base  27  of the gutter  22  blocks the openings  19   a  of the inner frame  19 . 
     The width W between opposite sides  39   a ,  39   a  of the guide plates  38  is set greater than the outside diameter D of the tubes  35  so that the guide plates  38  cover the tubes  35 . 
     FIG. 5 illustrates a drain nozzle  23   a  formed at the front wall  23  of the gutter  22  and the drain tube  60  connected to the drain nozzle  23   a . Specifically, the rear end of a tube body  61  of the drain tube  60  is fitted onto the drain nozzle  23   a  and a front nozzle  62  is fitted onto the tube body  61 . The tubular elastic materials  63  are fitted onto the tube body  61  as shown in FIG. 1 to be held between the outer panel  18  and the inner frame  19 . A flange  62   a  of the front nozzle  62  is fitted to an opening  19   b  of the inner frame  19 . Thus the tube body  61  is stably disposed in a space  17   c  between the outer panel  18  and the inner frame  19 . The front nozzle  62  communicates with the recess  45  of the gutter  22  via the tube body  61  and the drain nozzle  23 . Rainwater or wash water collected in the recess  45  of the gutter  22  is thus discharged from the front nozzle  62  through the tube body  61 . 
     FIGS. 6A and 6B illustrate hydrogen let out through the hydrogen ventilation duct  20 . 
     In FIG. 6A, hydrogen, if leaked from fuel cells for some reason when the fuel cells stop generating electricity, can enter motor room  54  through an intake duct. The hydrogen entering the motor room  54  flows into the space  55  inside the gutter  22  through the tubes  35  of the hydrogen ventilation duct  20 . The hydrogen then circumvents the guide plates  38  and flows from the opposite sides  39   a ,  39   a  of the guide plates  38  as shown by arrows. As described with FIG. 2, the guide plates  38  are curved to protrude toward the tubes  35 , having the convex surfaces  38   c . The hydrogen entering the space  55  inside the gutter  22  from the tubes  35  is thus guided smoothly along the convex surfaces  38   c  of the guide plates  38  to the opposite sides  39   a ,  39   a  as shown by arrows. 
     In FIG. 6B, the hydrogen circumventing the guide plates  38  (See FIG. 6A) flows along the rear surface  40   a  of the cover  40  toward the vent  41  and is let out through the vent  41  into the atmosphere. Specifically, the upward inclination of the cover  40  to the rear smoothly guides the hydrogen along the rear surface  40   a  of the cover  40  to the vent  41 . The smooth guidance of the hydrogen in the space  55  inside the gutter  22  to the vent  41  and the efficient emission of the hydrogen to the atmosphere as shown by arrows provide natural ventilation of the motor room  54  to eliminate the hydrogen. 
     Next, a case of entering of rainwater or wash water from the vent  41  of the hydrogen ventilation duct  20  will be described with reference to FIGS. 7A to  8 . 
     In FIG. 7A, rainwater or wash water, when entering from the vent  41  of the hydrogen ventilation duct  20  as shown by arrows {circle around ( 1 )}, flows into the space  55  inside the gutter  22 . Rainwater or wash water entering as shown by arrows {circle around ( 2 )} is intercepted by the guide plates  38 . 
     As shown in FIG. 7B, the rainwater or wash water intercepted by the guide plates  38  is guided along the guide plates  38 , flowing toward the base  27  of the gutter  22 , and then flows through the gaps between the lower ends  28   b  of the guide plates  38  and the base  27  of the gutter  22  toward the recess  45  as shown in FIG.  7 A. The guide plates  38  are curved to protrude toward the tubes  35  as shown in FIG. 7A with the surfaces  38   d  opposite to the vent  41  recessed. The rainwater or wash water coming in through the vent  41  toward the guide plates  38  as shown by arrows {circle around ( 2 )} is thus collected in the middle of the guide plates  38 . This securely prevents rainwater or wash water from going around the opposite ends  39   a ,  39   b  of the guide plates  38  and entering the tubes  35  from the upper ends  35   b  of the tubes  35 . 
     The rainwater or wash water entering as shown by arrows {circle around ( 2 )} flows along the guide plates  38  toward the base  27  of the gutter  22  as described above, being prevented from entering the tubes  35  from the upper ends  35   b  thereof. This prevents rainwater or wash water from entering the motor room  54  from the upper ends  35   b  of the tubes  35  through the tubes  35  and reaching various kinds of equipment inside the motor room  54 . 
     As shown in FIG. 8, rainwater or wash water flowing into the recess  45  of the gutter  22  flows through the drain nozzle  23   a  into the tube body  61 . The rainwater or wash water flowing into the tube body  61  flows through the tube body  61  to the front nozzle  62  and is discharged from the front nozzle  62 . This prevents water collected in the recess  45  of the gutter  22  from reaching various kinds of equipment inside the motor room  54 . 
     The above embodiment has been described with the guide plates  38  curved to protrude toward the tubes  35 . The shape of the guide plates  38  is not limited to the curved one. The guide plates  38  may be formed in a substantially V shape, for example, to provide similar effects. 
     The above embodiment has been described with the hydrogen ventilation duct  20  mounted in the vicinity of the rear end  17   a  of the hood  17 . The present invention is not limited thereto. The mounting position of the hydrogen ventilation duct  20  to the hood  17  is selectable in accordance with the shape of the fuel-cell vehicle  10 . 
     The above embodiment has been described with the lower ends  35   a  of the tubes  35  inserted in the openings  19   a  of the inner frame  19 . The present invention is not limited thereto. The lower ends  35   a  of the tubes  35  may be opposed to the openings  19   a  of the inner frame  19  without being inserted therein. 
     The present disclosure relates to the subject matter of Japanese Patent Application No. 2001-221936, filed Jul. 23, 2001, the disclosure of which is incorporated herein by reference in its entirety.