Patent attributes
Hydrogen leaking from a hydrogen cylinder has a lower specific gravity than air, thus rises in a cylinder housing space, and reaches a ventilating opening constituted by a group of slits formed in an upper surface of a roof cover. At this time, the ventilating opening is formed in a position above the hydrogen cylinder, and thus the leaking hydrogen can reach the ventilating opening in a short distance as compared with the case where the ventilating opening is formed in a position apart from the position above the hydrogen cylinder. The ventilating openings are provided in a plurality of locations, and thus the leaking hydrogen reaches the closest ventilating opening. The hydrogen gas reaches the ventilating opening, passes upward therethrough and flows outside.
