Personal watercraft engine fluid cooling system

Abstract

An engine fluid cooling system that utilizes the jet propulsion unit of a personal watercraft to cool the engine fluid. The cooling system includes passages for transporting engine fluid to and from a cooling system that includes a cooling channel formed about a component of the jet propulsion unit so that as the engine fluid travels through the cooling channel, heat, contained in the engine fluid, is transferred to the water flowing through the jet propulsion unit.

1 . A system for a personal watercraft having an engine fluid cooling apparatus, the system comprising: 
 a hull and an overlying deck, forming a cavity that defines an engine compartment;    an engine, located in the engine compartment, coupled to a jet propulsion unit for powering the watercraft; and    an engine fluid passage surrounding a component of the jet propulsion unit for directing the engine fluid through the engine fluid passage so that heat in the engine fluid is transferred to water taken up by the jet propulsion unit.    
   
   
       2 . The personal watercraft of  claim 1 , further including an engine fluid channel line coupling an engine fluid reservoir to the engine fluid passage for delivering heated lubricating fluid to the passage for cooling.  
   
   
       3 . The personal watercraft of  claim 1 , wherein the engine fluid passage is a conduit coiled about the component of the jet propulsion unit.  
   
   
       4 . The personal watercraft of  claim 1 , wherein the engine fluid passage is a coil formed about a jet pump housing of the jet propulsion unit.  
   
   
       5 . The personal watercraft of  claim 1 , wherein the engine fluid passage is a channel formed between an exterior of the component of the jet propulsion unit and a jacket formed about the component of the jet propulsion unit.  
   
   
       6 . The personal watercraft of  claim 5 , wherein the jacket is integral with the component of the jet propulsion unit.  
   
   
       7 . The personal watercraft of  claim 1 , wherein the engine fluid passage is a channel formed between an exterior of a jet pump housing of the jet propulsion unit and a jacket formed thereabout.  
   
   
       8 . An engine fluid cooling apparatus for a jet-propelled watercraft, comprising: 
 an engine fluid passage formed about a component of a jet propulsion unit for circulating engine fluid thereabout, and    an engine fluid passageway coupling an engine fluid reservoir to the engine fluid passage, wherein heated engine fluid is delivered to the engine fluid passage where it is cooled and then returned to the engine fluid reservoir.    
   
   
       9 . The cooling system of  claim 8 , wherein the engine fluid passage is formed by coiling a hollow conduit about the component of the jet propulsion unit.  
   
   
       10 . The cooling system of  claim 8 , wherein the engine fluid passage is a hollow conduit coiled about a stator of the jet propulsion unit.  
   
   
       11 . The cooling system of  claim 8 , wherein the engine fluid passage is formed by coiling a hollow conduit coiled about a jet pump housing of the jet propulsion unit.  
   
   
       12 . The cooling system of  claim 8 , wherein the engine fluid passage is a channel formed between an exterior of the component of the jet propulsion unit and a jacket that at least partially surrounds the component of the jet propulsion unit.  
   
   
       13 . The cooling system of  claim 12 , wherein the component of the jet propulsion unit is a stator.  
   
   
       14 . The cooling system of  claim 12 , wherein the component of the jet propulsion unit is a jet pump housing.  
   
   
       15 . A jet propulsion unit for a jet-propelled watercraft, comprising: 
 an outer housing;    an impeller journalled within the outer housing;    a discharge nozzle positioned rearward of the impeller; and    an engine lubricating fluid channel formed contiguously with the outer housing so that heat from an engine fluid is transferred to water flowing through the jet propulsion unit.    
   
   
       16 . The jet propulsion unit of  claim 15 , wherein the engine lubricating fluid channel is couplable to an engine lubricating fluid reservoir.  
   
   
       17 . The jet propulsion unit of  claim 15 , wherein the engine lubricating fluid channel is a hollow conduit coiled around the outer housing.  
   
   
       18 . The jet propulsion unit of  claim 17 , wherein the hollow conduit is coiled around a jet pump housing.  
   
   
       19 . The jet propulsion unit of  claim 17 , wherein the hollow conduit is coiled around a stator of the jet propulsion unit.  
   
   
       20 . The jet propulsion unit of  claim 15 , further comprising an inlet in the engine lubricating fluid channel for receiving heated lubricating fluid from an engine of the watercraft.  
   
   
       21 . The jet propulsion unit of  claim 20 , further comprising an outlet in the engine lubricating fluid channel for diverting cooled lubricating fluid back to the engine.  
   
   
       22 . A cooling system for cooling an engine fluid of a watercraft, comprising: 
 cooling means formed about a component of the jet propulsion unit; and    means for transporting the engine fluid to and from the cooling means.    
   
   
       23 . A method of cooling an engine fluid of a watercraft, the method comprising the steps of: 
 diverting an engine fluid from a circulatory path to an engine fluid cooling system located at a jet propulsion unit of a watercraft;    transferring heat stored in the engine fluid to ambient water traveling through the jet propulsion unit thereby cooling the engine fluid; and    returning the cooled engine fluid to its circulatory path.    
   
   
       24 . A method of cooling an engine fluid in a watercraft, comprising the step of: 
 circulating a heated engine fluid adjacent to a component of a jet propulsion unit so that heat contained in the engine fluid is transferred to ambient water flowing through the jet propulsion unit.