Marine propulsion – Means for accomodating or moving engine fluids – Cooling for engine
Reexamination Certificate
1998-11-25
2001-05-29
Basinger, Sherman (Department: 3617)
Marine propulsion
Means for accomodating or moving engine fluids
Cooling for engine
C123S533000
Reexamination Certificate
active
06238258
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a personal watercraft and more particularly to an improved direct injected engine therefore that includes an air fuel injector.
In order to improve the efficiency and exhaust emission control for two cycle engines to permit their continued use in applications where compact, high output engines are required, it has been proposed to employ direct cylinder injection systems. Such systems inject the fuel directly into the combustion chamber of the engine. This permits more efficient control of the amount of fuel introduced as well as the timing thereof to improve engine efficiency.
With two cycle engines, on the other hand, at least a portion of the injection cycle takes place at the same time scavenging is occurring and hence, the fuel must be injected fairly rapidly over a relatively short time period to avoid escape along with the exhaust gasses. This results in high injection pressures that can present problems such as fuel condensation on the walls of the combustion chamber.
It has been well known that in order to improve fuel atomization, air may be injected along with the fuel so as to prevent these problems. This concept was utilized in the earliest internal combustion engines. However, the application of air fuel injectors for such small, compact arrangements such as personal watercraft presents significant problems.
A personal watercraft is a well known type of watercraft which may assume many forms. However, a common characteristic of all personal watercraft is that they are designed to be operated by a single rider who may carry no more than two or three additional passengers with him. Also, these watercraft are quite compact and sporting in nature. Frequently, the operator and his passengers are seated in straddled, tandem fashion on a single seat that overlies, in part, the engine compartment.
Thus, the engine is positioned in a quite confined location. This is one reason why two cycle engines are desirable for such application. However, where added components such as the components necessitated by a fuel, air injector are incorporated, then the positioning of the components, their serviceability and other factors, which will be mentioned, become quite significant.
It is important that the air that is used with the injection system is compressed to a high enough pressure. Therefore, it is common to use positive displacement pumps for this purpose. However, regardless of the type of air compressor employed, this gives rise to fairly high temperatures. Thus it is important that the compressed air is not heated so highly that it looses its effectiveness.
It is, therefore, a principal object of this invention to provide an improved fuel air injector system for a personal watercraft wherein the air for the compressor and the compressor systems are such that the compressor will be well cooled.
Also, because of the sporting nature of these watercraft, there is a danger that water may enter the air injection system. This can happen due to the fact these watercraft frequently become inverted and subsequently righted. If the air system is such that it becomes immersed in water during this inversion and righting process, then damage can result.
It is, therefore, a still further object of this invention to provide an improved air compressor arrangement for a personal watercraft wherein the compressor and its components are protected from the water.
SUMMARY OF THE INVENTION
This invention is adapted to be embodied in a personal watercraft having a hull with a rider's area designed to accommodate a single operator rider and no more than three passengers. The hull also forms an engine compartment in which an internal combustion engine is positioned. The engine is provided with a fuel air injector that injects fuel and a source of high pressure air into the combustion chamber for combustion therein. The compressed air is supplied to the fuel air injector by an air compressor that draws air from within the engine compartment and which delivers it to the fuel air injector.
In accordance with a first feature of the invention, the inlet for the air compressor is disposed so that it will be above the water level even when the watercraft is inverted and again righted.
In accordance with another feature of the invention, a cooling arrangement is provided for cooling the air compressor.
REFERENCES:
patent: 4068612 (1978-01-01), Meiners
patent: 5233952 (1993-08-01), Isaka
patent: 5239970 (1993-08-01), Kurihara
patent: 5261356 (1993-11-01), Takahashi et al.
patent: 5375578 (1994-12-01), Kato et al.
patent: 5390621 (1995-02-01), Hattori et al.
Basinger Sherman
Beutler Ernest A.
Yamaha Hatsudoki Kabushiki Kaisha
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