Marine propulsion – Means for accomodating or moving engine fluids – Means for handling exhaust gas
Reexamination Certificate
1999-03-01
2001-04-10
Morano, S. Joseph (Department: 3617)
Marine propulsion
Means for accomodating or moving engine fluids
Means for handling exhaust gas
C440S038000, C114S055500, C060S312000, C060S321000
Reexamination Certificate
active
06213827
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a watercraft and more particularly to a personal watercraft and an engine exhaust system for such watercraft.
Personal watercraft have enjoyed a substantial amount of success and are quite popular. This type of watercraft is generally recognized as a relatively small watercraft that is designed primarily for operation by a rider who may carry with him no more than two or three additional passengers. This type of watercraft is, as well known, quite sporting in nature.
Because of their small size and high degree of maneuverability, however, there are certain objections to the use of these watercraft on some bodies of water. One of these objections is caused by the fact that this type of watercraft, primarily because of its small size, has a relatively simple exhaust system that does not provide a significant degree of silencing.
This result is mandated primarily by the very compact nature of the watercraft and the relatively small area that is available for exhaust treatment. Because these watercrafts can be utilized on quite small bodies of water, the potential noise may be more objectionable than larger watercraft having unmuffled exhaust systems but which do not operate on these small bodies of water.
This, therefore, a principal object of this invention to provide an improved exhaust system and particularly an exhaust silencing system for personal watercraft.
It is a further object of this invention to provide an improved and compact, yet highly effective silencing system for the exhaust of a personal watercraft.
Generally, personal watercraft may employ one or more expansion chambers which can provide some at relatively limited silencing effect. That is, the conventional exhaust system employed with a personal watercraft does not use a silencing system that embodies a muffler of the type utilized with other engine applications.
The types of mufflers employed in these other applications depend upon the type and acoustical range of silencing to be effected, but they can use a variety of devices such as a plurality of separate expansion chambers interconnected by small interconnecting passages, silencing devices such as Helmholtz resonators or perforated tubes surrounded by an expansion chamber.
It is, therefore, a further object of this invention to provide an improved exhaust system for a personal watercraft that can employ a muffler or silencing device of the noted types.
One difficulty with the incorporation of a muffler or similar silencing device in a personal watercraft, in addition to the space, is the heat that may be generated by such devices. It is, therefore, another object of this invention to provide an improved cooling arrangement for the muffler or silencer of a personal watercraft exhaust system.
The components of the exhaust system also may be relatively bulky in size and can become heavy, particularly if multiple chambers and multiple shells are employed. Because of the small nature of a personal watercraft, therefore, the placement of these components becomes critical so as to maintain the proper balance for the watercraft, particularly when a number of passengers or the seating location of a single rider may vary.
It is, therefore, a still further object of this invention to provide an improved component layout for the exhaust system of a personal watercraft.
In addition to employing expansion chambers and silencing devices, it may also be desirable to provide a catalyst in the exhaust systems for treatment of exhaust gases so as to prevent the emission of unwanted exhaust gas constituents to the atmosphere or to the body of water in which the watercraft is operating. This further complicates the positioning and location of the exhaust system components. This is particularly true if cooling arrangements are employed for the muffler inasmuch as the catalyst should be operated at a relatively high temperature in order to become effective. Thus, the catalyst should not be overcooled.
It is, therefore, a still further object of this invention to provide an improved catalytic and silenced exhaust system for a personal watercraft.
In addition to the aforenoted features, it is also desirable to employ certain sensors in the exhaust system. The placement of the sensors also is important. Furthermore, the sensors should be positioned so that they can be conveniently accessed for servicing.
It is, therefore, yet another object of this invention to provide an improved exhaust system and sensor arrangement for a personal watercraft wherein the sensor components can be conveniently accessed.
SUMMARY OF THE INVENTION
This invention is adapted to be embodied in a personal watercraft having a hull that defines a rider's area that is sized to accommodate a rider operator and no more than a few additional passengers. The hull defines a engine compartment in which a powering internal combustion engine is provided. The engine is mounted in the hull and drives a propulsion device for propelling the watercraft through a transmission. The engine is provided with an exhaust system including at least one exhaust port for discharging exhaust gases from a combustion chamber of the engine. The exhaust system collects the exhaust gases from the exhaust port and discharges them to the atmosphere. The exhaust system incorporates at least one silencer having an acoustical silencing device for silencing the exhaust gases.
In accordance with one feature of the invention, the exhaust silencer is provided with a cooling jacket through which cooling water is circulated and this cooling water is discharged to the body of water in which the watercraft is operating through the exhaust system.
In accordance with another feature of the invention, the exhaust system is also provided with a pair of sensors that sense different exhaust conditions. The engine compartment is provided with an access opening that is normally closed by a removable closure. These sensors are accessible through this access opening.
In accordance with another feature of the invention, the exhaust system also includes a water lock device that is disposed downstream of the exhaust silencer. The exhaust silencer and water lock device are interrelated so as to provide balance to the hull by positioning them on opposite sides of a plane that extends in either one of a transverse or longitudinal direction of the watercraft.
In accordance with another feature of the invention, the engine compartment of the watercraft is provided with a ventilating system and the engine has an air inlet system. The exhaust silencing device is interrelated with these air systems for positioning it so that cooling air flows across the exhaust silencing device.
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Hattori Toshiyuki
Nanami Masayoshi
Beutler Ernest A.
Morano S. Joseph
Vasudeva Ajay
Yamaha Hatsudoki Kabushiki Kaisha
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