Exhaust system, hull, and speed indicator for watercraft
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsHisato Yamada, Mitsuhisa Hirano, Yasukazu Kojima
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Abstract
A personal watercraft exhaust system, hull underplate, and speed sensor and sponson arrangement. The exhaust system for the engine provides a compact assembly that incorporates a pair of expansion chamber devices on opposite sides of the tunnel to provide a water-trap effect, effective silencing, and still clear storage compartments of the hull. The sponsons are configured so as to improve the buoyancy and provide stability upon leaning, and the underplate mounts a speed sensor to the rear of but below the jet propulsion unit discharge so as to provide a good speed signal and to protect the speed sensor.
Claims27
A watercraft comprised of a hull with an undersurface defining a tunnel at the rear end thereof, a propulsion device positioned at least in part within said tunnel for propelling said watercraft, said hull further defining an engine compartment containing an engine for driving said propulsion device, said engine having an exhaust system for discharging exhaust gases from exhaust ports thereof to the atmosphere, said exhaust system comprising first and second exhaust treatment devices positioned within said hull on opposite sides of said tunnel, each of said exhaust treatment devices being comprised of an outer housing defining at least one expansion chamber therein, an exhaust pipe extending from said engine on one side of said hull and opening into said first exhaust treatment device at one longitudinal end thereof for delivering exhaust gases from said engine thereto, a generally inverted U-shaped transfer pipe extending over said tunnel from an inlet end at an upper portion of said first exhaust treatment device at the other longitudinal end thereof and terminating at a discharge end in an upper portion of said second exhaust treatment device at a position forwardly of the aft end of said second exhaust treatment device, and an exhaust discharge pipe extending from said aft end of said second exhaust treatment device for discharging exhaust gases to the atmosphere.
A watercraft comprised of a hull with an undersurface defining a tunnel at the rear end thereof, a jet propulsion unit positioned at least in part within said tunnel for propelling said watercraft, said jet propulsion unit having the discharge nozzle formed at the rear end thereof through which water is discharged for propelling said jet propulsion unit, a combined speed sensor and closure plate affixed to the underside of said hull and spanning the rear of said tunnel for closing said tunnel, said speed sensor and closure plate having a downwardly projection portion disposed beneath said discharge nozzle at the rear end thereof defining a gap and a propeller type speed sensor mounted at the rear end of said closure and speed sensor plate in said gap for providing a speed indicating signal.
Dependencies are inferred from the claim text.