Internal-combustion engines – Charge forming device – Crankcase vapor used with combustible mixture
Reexamination Certificate
2001-02-28
2003-07-15
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Crankcase vapor used with combustible mixture
C123S1960CP
Reexamination Certificate
active
06591819
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a new engine for use in, for example, personal watercraft. In particular, the present invention relates to a new four-stroke in-line engine that was developed with a view to the future stricter environmental and emission regulations. The engine has a blow-by ventilation system for separating lubricant that may be entrained within blow-by gases. The engine further includes an improved lubrication system.
BACKGROUND OF THE INVENTION
There is a very popular type of watercraft known as a “personal watercraft” which is designed to be operated primarily by a single rider. Although this type of watercraft is commonly employed for single riders, frequently provisions are made for accommodating additional passengers although the maximum number of passengers is more limited than conventional types of watercraft.
This type of watercraft is also generally quite sporting in nature and normally accommodates at least the rider on a type of seat in which the rider sits in a straddle fashion. The passenger's area is frequently open through the rear of the watercraft so as to facilitate entry and exit of the rider and passengers to the body of water in which the watercraft is operating, as this type of watercraft is normally ridden with passengers that are wearing swimming suits.
These personal watercraft are generally quite small so that they can be conveniently transported from the owner's home to a body of water for its use. Because of the small size, the layout of the components is extremely critical, and this gives rise to several design considerations that are peculiar to this type of watercraft. However, due to its sporting nature, it is also desirable that the watercraft be powered by an engine and propulsion device that is not only efficient but also generates sufficient power.
Traditionally, two-cycle engines have been used to power watercraft, including personal watercraft. These engines have the advantage that they are fairly powerful, relatively lightweight, and compact.
One particular disadvantage to the two-cycle engine is its emission content. Two-cycle engines generally exhaust larger quantities of hydrocarbons and other pollutants than four-cycle engines due to cylinder charging inefficiencies and the combustion of lubricating oil among other things. When measures are taken to reduce emissions of the two-cycle engine, other generally undesirable consequences can result, such as an increase in the weight of the engine, a reduction of its power output or the like. With concern for the environment and increasingly strict emissions requirements being instituted by various governing bodies There is motivation to provide a power plant that reduces exhaust emissions while retaining other advantageous characteristics such as compactness, low weight and high power output.
Four-cycle engines are commonly used as power plants in other applications, such as automobiles. These engines have the advantage that their emissions output are generally desirably lower as compared to a two-cycle engine for a given power output.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a four stroke, in-line engine having a compact construction.
It is another object of the present invention to provide a four stroke, in-line engine having a modular construction to permit the interchange of parts between various engine models.
It is another object of the present invention to provide a four stroke, in-line engine having improved exhaust emission characteristics.
It is another object of the present invention to provide a four stroke engine having a narrow and low profile.
It is another object of the present invention to provide a four stroke engine having a low profile valve actuation assembly for controlling the operation of the intake and exhaust valves.
It is another object of the present invention to provide a cylinder head having a low profile to reduce engine height.
It is another object of the present invention to offset the placement of the intake valves and exhaust valves with respect to a vertical axis within the cylinder head to reduce engine height.
It is another object of the present invention to provide an improved spark plug mounting assembly for easy access within the cylinder.
It is another object of the present invention to provide a Y-shaped intake rocker arm assembly for easy access within the cylinder.
It is yet another object of the present invention to provide a four stroke engine having an improved oil collection system and oil holding tank.
It is another object to provide a four stroke engine which combines a closed loop cooling system and an open loop cooling system for enhanced cooling of the engine in accordance with the present invention.
It is another object to provide an open loop cooling system for cooling an exhaust manifold in accordance with the present invention, wherein the open loop cooling system enhances cooling of the crankcase and cylinder head.
It is another object to provide an open loop cooling system for cooling an exhaust manifold in accordance with the present invention, wherein the open cooling system lowers the temperature of the exhaust manifold such that the exhaust manifold functions as a heat sink for the crankcase and cylinder head.
It is another object of the present invention to provide a closed loop cooling system for selectively cooling the crankcase and cylinder head of the four stroke engine.
It is another object of the present invention to provide a closed loop cooling system having a selectively operable heat exchanger.
It is another object of the present invention to provide a supercharger for enhanced engine performance.
SUMMARY OF THE INVENTION
The present invention is directed to a four stroke internal combustion engine having an improved lubrication system and system for separating lubricant from blow-by gas within the crank case. The present invention is also directed to a personal watercraft having the same. The engine includes a crankcase, and a cylinder head connected to the crankcase, which together form at least one cylinder. The crankcase includes at least one crank chamber located below the cylinder. A crankshaft is rotatably mounted within the crankcase and extends through each crank chamber. The engine further includes intake valves and exhaust valves associated with each cylinder. A valve actuation assembly located in the cylinder head for operating the valves.
The engine further includes a lubrication tank formed in the crankcase. The lubrication tank includes a lower portion located beneath the crank chamber and an upper portion extending upwardly along one side of the crankcase. A balance shaft is rotatably mounted within the crankcase. The balance shaft extends parallel to the crankshaft through the upper portion of the lubrication tank. A baffle may be provided in the upper portion of the lubrication tank to cover a portion of the balance shaft.
The crankshaft and the balance shaft extend from the crankcase into a power take off housing located on one end of the crankcase. A rotating member is secured to the crankshaft within the power take off housing. The rotating member is operatively coupled within the power take off housing to the balance shaft.
The power take off housing includes a lubricant collection portion formed in a lower portion the power take off housing. A first lubricant pump is located within the power take off housing. The lubricant pump is operatively connected to the balance shaft. A lubricant transfer passageway extends from one end of the crankcase adjacent the power take off housing to an opposite end of crankcase. The lubricant transfer passageway is operatively connected to a lubricant sieve. The lubricant sieve may be connected to a second lubricant pump. The second lubricant transfer passageway extends from the second lubricant pump to the lubrication tank. The power take off housing includes an integrally formed oil filter housing. The oil filter includes a drainage port located within the oil filte
Ennsmann Roland
Tscherne Rudolf
Wolfsgruber Alois
Bombardier-Rotax GmbH
McMahon Marguerite
Pillsbury & Winthrop LLP
LandOfFree
Four stroke engine having blow-by ventilation system and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Four stroke engine having blow-by ventilation system and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Four stroke engine having blow-by ventilation system and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3075022