Cooling system for small watercraft engine

Abstract

A small watercraft engine having a lubrication system including a lubrication oil reservoir defining a cooling water jacket therein. A cooling system of the engine supplies cooling water to the water jacket. The water jacket includes at least one rib, and preferably a plurality of ribs, to guide the cooling water within the water jacket. The ribs may be arranged to guide cooling water from a lower portion of the water jacket to an upper portion of the water jacket through two or more generally distinct horizontal regions. Preferably, a pair of baffle arrangements are disposed within the oil reservoir. A first baffle arrangement separates the interior space of the reservoir from a breather chamber which communicates with the intake system. A second baffle arrangement is configured to generally retain oil within a lower portion of the reservoir so as to be available to a delivery port, which delivers oil to an oil pump of the engine. The delivery port desirably tapers in diameter from an upper end to a lower end to supply an ample amount of oil to the oil pump when the watercraft is leaning.

What is claimed is:  
     
         1 . A watercraft comprising a hull including a lower portion and an upper portion, an engine compartment defined between the upper and lower portions, a four-cycle internal combustion engine supported within the engine compartment, the engine including an engine body defining at least one combustion chamber therein, and a valve train comprising at least one intake valve configured to control air flow into the combustion chamber and at least one exhaust valve configured to control flow of exhaust gases out of the combustion chamber, a crankshaft journaled for rotation at least partially within the engine body, a plurality of oil galleries defined within the engine body configured to guide oil to at least portions of the valve train and the crankshaft, an oil reservoir, an oil pump arrangement configured to circulate oil between the reservoir and the oil galleries, the reservoir including an inlet through which the pump arrangement delivers oil to the reservoir, the reservoir also including an outlet, through which oil passes from the reservoir to the pump arrangement, the outlet being disposed at a lower portion of the reservoir and comprising a tapered oil guide having an inlet end opening into an interior of the reservoir and a smaller outlet end below the inlet end opening into a passage leading to the pump arrangement, the tapered oil guide having side walls that are inclined more steeply than a maximum inclination of a surface of oil within the reservoir when the watercraft is maneuvered through at least one of a high speed turn or maximum acceleration.  
     
     
         2 . The watercraft according to  claim 1 , wherein a cross-section of the tapered guide, taken along a horizontal plane, is oblong.  
     
     
         3 . The watercraft according to  claim 1 , wherein the inclination of the side walls of the tapered guide is about 40-80 degrees from horizontal.  
     
     
         4 . A watercraft comprising a hull, an engine supported by the hull, a lubricant reservoir configured to contain lubricant for the engine, the reservoir having an outlet, a lubricant pump having an inlet connected to the outlet of the reservoir and an outlet connected to the engine, the outlet of the reservoir comprising a tapered portion having an inlet end opening into an interior of the reservoir and a smaller outlet connected to the pump, the tapered portion including side walls being tapered at an angle of about 40 to 80 degrees from horizontal.  
     
     
         5 . The watercraft according to  claim 4 , wherein the tapered portion is disposed at a bottom of the reservoir.  
     
     
         6 . The watercraft according to  claim 4 , wherein a cross section of the tapered portion, taken along a horizontal plane, is oblong.  
     
     
         7 . The watercraft according to  claim 4 , wherein the tapered portion is conical.  
     
     
         8 . The watercraft according to  claim 4 , wherein the side walls of the tapered portion are inclined more steeply than a surface of oil within the reservoir when the watercraft is maneuvered in at least one of a high speed turn and abrupt acceleration.  
     
     
         9 . The watercraft according to  claim 4  additionally comprising a first baffle disposed above the tapered portion and below an upper portion of the reservoir.  
     
     
         10 . The watercraft according to  claim 9  additionally comprising a baffle arrangement positioned at a top of the reservoir, the baffle arrangement configured to allow gases to flow threrethrough and inhibit liquids from passing therethrough.  
     
     
         11 . The watercraft according to  claim 4  additionally comprising an inlet disposed at a lower portion of the reservoir, and a wall extending upwardly from a position below the inlet, the wall dividing the interior of the reservoir into a main oil reservoir portion and a staging area, the outlet being connected to the main oil reservoir portion.  
     
     
         12 . The watercraft according to  claim 11  additionally comprising a cooling jacket in thermal communication with at least a portion of the reservoir, the staging area being in thermal communication with the cooling jacket.  
     
     
         13 . The watercraft according to  claim 4 , wherein the inlet of the tapered portion is curvilinear, the reservoir comprising flat interior side walls having lower portions that are inclined inwardly toward the inlet of the tapered portion.  
     
     
         14 . A lubricant reservoir comprising an interior volume configured to store lubricant and an outlet comprising a tapered portion having an inlet end and an outlet end, the outlet being smaller than the inlet, the tapered portion having side walls that are inclined at an angle of about 40 to 80 degrees from horizontal.  
     
     
         15 . The reservoir according to  claim 14 , wherein a cross section of the tapered portion, taken along a horizontal plane, is oblong.  
     
     
         16 . The reservoir according to  claim 14 , wherein the tapered portion is conical.  
     
     
         17 . The reservoir according to  claim 14  additionally comprising a first baffle disposed above the tapered portion and below an upper portion of the reservoir.  
     
     
         18 . The reservoir according to  claim 17  additionally comprising a baffle arrangement positioned at a top of the reservoir, the baffle arrangement configured to allow gases to flow threrethrough and inhibit liquids from passing therethrough.  
     
     
         19 . The reservoir according to  claim 14  additionally comprising an inlet disposed at a lower portion of the reservoir, and a wall extending upwardly from a position below the inlet, the wall dividing the interior of the reservoir into a main oil reservoir portion and a staging area, the outlet being connected to the main oil reservoir portion.  
     
     
         20 . The reservoir according to  claim 19  additionally comprising a cooling jacket in thermal communication with at least a portion of the reservoir, the staging area being in thermal communication with the cooling jacket.  
     
     
         21 . The reservoir according to  claim 14 , wherein the inlet of the tapered portion is curvilinear, the reservoir comprising flat interior side walls having lower portions that are inclined inwardly toward the inlet of the tapered portion.  
     
     
         22 . A watercraft comprising a hull, an engine supported by the hull, a lubricant reservoir configured to contain lubricant for the engine, the reservoir having an outlet, a lubricant pump having an inlet connected to the outlet of the reservoir and an outlet connected to the engine, the outlet of the reservoir comprising means for preventing abrupt movements of the watercraft, during upright operation, from causing the outlet to be exposed to air within the reservoir.