Marine propulsion – Means for accomodating or moving engine fluids – Cooling for engine
Reexamination Certificate
2000-02-03
2002-10-08
Morano, S. Joseph (Department: 3617)
Marine propulsion
Means for accomodating or moving engine fluids
Cooling for engine
Reexamination Certificate
active
06461207
ABSTRACT:
PRIORITY INFORMATION
The present application is based on and claims priority to Japanese Patent Application No. 11-26577, the entire contents of which is hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a lubrication system of an internal combustion engine. More particularly, the present invention relates to a lubrication system of a small watercraft engine that powers a water propulsion device.
2. Description of Related Art
Personal watercraft have become very popular in recent years. An enthusiasm for competition has grown with this popularity, and as a result personal watercraft have become increasingly fast. Many personal watercraft today are capable of speeds well in excess of 60 mph. To attain such speeds, personal watercraft are typically driven by high power output motors.
Two-cycle engines commonly power personal watercrafts, as these engines have the advantage of being fairly powerful and relatively light and compact. One particular disadvantage of a two-cycle engine though, is emissions content. Two-cycle engines exhaust large quantities of carbon monoxide and various hydrocarbons. However, when steps are taken to reduce the emissions content of a two-cycle engine, other generally undesirable consequences result, such as an increase in the weight of the engine, cost of manufacture, and reduction of its power output.
Thus, four-cycle engines have now been proposed as the power plant for personal watercraft. These engines have the advantage of less hydrocarbon emissions than a two-cycle engine while maintaining a relatively high power output. It is therefore desirable to provide a small watercraft with a four-cycle engine in order to reduce exhaust emissions without significantly impacting the power output of the engine that powers the watercraft.
SUMMARY OF THE INVENTION
The present invention involves, in part, the recognition that several problems arise in connection with employing a four-cycle engine within a small watercraft. One such problem involves the fact that four-cycle engines are typically include wet-sump type lubrication system which require oil filled crankcases or reservoirs positioned at or near the bottom of the cylinder block of the engine. When this type of engine is mounted in a personal watercraft, the associated oil pump may not consistently draw oil from the crankcase as the oil sloshes from side-to-side with abrupt maneuvers of the watercraft.
If a large oil pan is provided at the bottom of the crankcase, the output of the engine must be raised further above the bottom surface of the hull of the watercraft, thus, affecting the angle at which the engine must be mounted within the hull so that the output shaft of the engine can reach the propulsion device, such as a jet pump, provided at the aft of the hull. Further, because the engine compartments of personal watercrafts are typically confined beneath the seat of the watercraft, upon which a user may sit in a straddle-type fashion, the overall width of the engine compartment directly affects the comfort level of a user sitting on the seat. Thus, the engine compartment is usually quite limited in space.
The present invention therefore provides an engine of a personal watercraft with a lubrication system which allows a four-cycle internal combustion engine to be mounted with its crankshaft close to a bottom surface of the hull and which minimizes the overall width of the engine compartment.
One aspect of the present invention provides a small watercraft comprising a hull defining an engine compartment and an internal combustion engine located within the engine compartment. A propulsion device is also carried by the hull and is driven by an output shaft of the engine to propel the watercraft. The engine includes a lubrication system having at least one lubricant pump, a lubricant reservoir and a lubricant filter, the pump being configured to circulate lubricant between the reservoir, the engine and the filter. The reservoir is arranged on one side of the engine and the filter is arranged in front of or behind the reservoir on the same side of the engine as the reservoir.
By arranging the lubricant filter forwardly or a rearwardly of the lubricant reservoir and on a same side of the engine as the reservoir, the present invention provides an engine having a lubrication system that is compact and allows the overall width of an engine compartment containing the engine to be minimized.
In accordance with a further aspect of the present invention, a watercraft is provided including a hull defining a engine compartment, an internal combustion engine contained within the engine compartment, and a lubrication system having a reservoir, a filter, and at least one pump, the pump being configured to circulate lubricant between the reservoir, the engine, and the filter. The engine also includes an exhaust manifold communicating with at least one of the combustion chambers defined within the engine. According to the invention, the oil filter is arranged on the same side of the engine as the exhaust manifold and on a rear side or a front side of the exhaust manifold. By arranging the oil filter as such, the effect on the overall width of the engine caused the oil filter is minimized, thus allowing the width of a seat mounted to the ending compartment to be constructed in a such a way so as to be comfortable for a rider to sit upon in a straddle-type fashion.
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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Morano S. Joseph
Wright Andrew
Yamaha Hatsudoki Kabushiki Kaisha
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