Marine propulsion – Jet drive
Reexamination Certificate
1999-06-11
2001-06-12
Morano, S. Joseph (Department: 3617)
Marine propulsion
Jet drive
C440S040000, C114S055500, C114S055510
Reexamination Certificate
active
06244913
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the propulsion and cooling systems for a personal watercraft. More particularly, the present invention relates to a propulsion unit assembly for a personal watercraft.
2. Description of the Related Art
Personal watercraft have become very popular in recent years. This type of watercraft is sporting in nature; it turns swiftly, is easily maneuverable, and accelerates quickly. Personal watercraft today commonly carry one rider and one, two or three passengers.
Personal watercraft typically incorporate an engine and associated components within a substantially sealed hull, with one or more air ducts piercing the hull to provide atmospheric air for cooling of the engine and for combustion. While atmospheric air may be sufficient for cooling smaller engines and associated components, as the engines incorporated into personal watercraft become increasingly powerful, cooling requirements for such engines and their associated components significantly increase. To accommodate these increased cooling requirements, therefore, various auxiliary cooling arrangements utilizing fluid from the jet pump unit have been proposed, including cooling of the oil and/or fuel used in the engine, as well as direct cooling of the engine itself. For example, some watercraft auxiliary cooling systems utilize ambient water pumped directly from the pressurization chamber of the installed jet pump unit through a conduit to the engine and/or associated cooled components. Typically attached to a fitting formed on the outer surface of the pressurization chamber, the cooling water conduit passes through the pump chamber, is routed through an opening in the tunnel wall, and travels through the hull interior to the a desired location.
In addition, as labor and production costs for manufacturing personal watercraft increase, manufacturers and consumers alike have become increasingly sensitive to the costs associated with the manufacture of personal watercraft. One time-consuming assembly step, and thus a significant expense in the manufacture of personal watercraft, relates to the installation of the propulsion unit onto the hull of the watercraft. Because the propulsion unit commonly must be adjusted with respect to the longitudinal axis of the watercraft for a proper coupling between the propulsion unit and the engine, propulsion units are often improperly aligned when initially installed on the watercraft hull and must be repositioned during the assembly process. When an alignment discrepancy is found, such units must be re-aligned and re-connected, normally by manufacturing personnel. Moreover, if the propulsion unit was sufficiently misaligned when it was originally installed, the numerous holes cut into the watercraft hull may be inadequate to effect proper mounting of the propulsion unit when in the proper orientation. In such a case, the watercraft hull might require significant repair and/or replacement before the propulsion unit may be properly re-installed.
SUMMARY OF THE INVENTION
The present invention involves in part the recognition that the installation and subsequent repair of misaligned propulsion units in personal watercraft constitutes a significant avoidable cost in the manufacture of personal watercraft. Thus, a need exists for a mounting arrangement which can quickly, easily and properly orient a propulsion unit before installation on a watercraft. In addition, the present invention involves in part the recognition that a cooling water conduit formed integrally within the wall of the propulsion unit obviates the need for an independent cooling water conduit line within the pump chamber of the watercraft, thus reducing the complexity and number of components located within the pump chamber of the watercraft and simplifying the installation of the propulsion unit.
The present invention discloses a propulsion unit assembly which allows for quick and easy installation of a properly oriented jet pump unit to the hull of the watercraft. The present invention also incorporates a coolant delivery system which provides a pressurized flow of cooling fluid without the presence of a conduit disposed next to the jet pump unit.
Accordingly, one aspect of the present invention involves a personal watercraft comprising a hull having a longitudinal axis. An engine compartment is defined within the hull and an engine is mounted within the engine compartment. A tunnel is defined as an underside of the hull. The tunnel incorporates a front wall having two or more alignment or positioning bosses which cooperate with stoppers on a mounting plate for the propulsion unit of the watercraft. When the alignment bosses are in contact with the stoppers, the mounting plate is properly oriented with respect to the longitudinal axis of the watercraft, and the mounting plate is then attached to the watercraft. When the propulsion unit is later attached to the mounting plate, the proper orientation of the mounting plate ensures that the propulsion unit is properly oriented when installed. It is also understood that the housing for the propulsion unit can additionally or alternatively include similar stoppers that cooperate with bosses formed on the wall(s) of the hull tunnel.
Another aspect of the present invention involves a propulsion unit assembly incorporating an integral cooling fluid delivery system which taps the high-pressure ambient water in the jet propulsion unit, redirecting a small portion of this high-pressure water to the engine and associated engine components for cooling. The integral cooling fluid delivery system includes a series of passages formed within the walls of the pressurization chamber housing, the impeller housing, and the mounting plate. Cooling fluid from the pressurization chamber thus passes through these passages and into the hull interior. Because the disclosed fluid delivery system transfers cooling fluid within the casing of the propulsion unit, there is no need for an independent conduit line for cooling fluid running through the pump chamber of the watercraft, which reduces the number and complexity of components running throughout the pump chamber of the watercraft and simplifies the installation of the propulsion unit.
Further aspects, features, and advantages of the present invention will become apparent from the detailed description of the preferred embodiments which follow.
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Hirano Mitsuhisa
Matsumoto Chihiro
Nagafusa Makoto
Knobbe Martens Olson & Bear LLP
Morano S. Joseph
Vasudeva Ajay
Yamaha Hatsudoki Kabushiki Kaisha
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