Cooling system for small watercraft

Abstract

A cooling system particularly suited for use in a small watercraft. The cooling system desirably supplies coolant to, and evacuates coolant from an engine of the watercraft. The engine includes an engine body defining at least one water jacket therein. A pressure actuated valve is desirably positioned upstream from the water jacket. A temperature actuated valve is desirably positioned downstream from the water jacket. The pressure actuated valve opens at a predetermined threshold fluid pressure to allow coolant to bypass, desirably, both the water jacket of the engine and the temperature actuated valve. Preferably, the threshold fluid pressure is lower than a fluid pressure that will damage the temperature actuated valve.

What is claimed is:  
     
         1 . A small watercraft comprising a hull defining an engine compartment, an internal combustion engine disposed in the engine compartment, a propulsion device driven by the engine, the engine having an engine body defining a combustion chamber, a cooling jacket at least partially surrounding the combustion chamber, a cooling system in fluid communication with the cooling jacket, the cooling system supplying cooling fluid to the cooling jacket and comprising a pressure actuated valve and a temperature actuated valve, the cooling jacket being between the pressure actuated valve and the temperature actuated valve.  
     
     
         2 . The small watercraft of  claim 1 , wherein the pressure-activated valve permits cooling fluid to bypass the engine when the cooling fluid upstream from the temperature actuated valve is above a predetermined threshold pressure.  
     
     
         3 . The small watercraft of  claim 1 , wherein the temperature actuated valve substantially prevents cooling fluid to from exiting the engine body when the cooling fluid within the cooling jacket is below a predetermined temperature.  
     
     
         4 . The small watercraft of  claim 3 , wherein the predetermined temperature is about 50 degrees centigrade.  
     
     
         5 . The small watercraft of  claim 1 , additionally comprising a lubrication system including a lubricant reservoir, the cooling system comprising a reservoir supply passage for supplying cooling fluid to a cooling jacket of the reservoir independently of the engine.  
     
     
         6 . The small watercraft of  claim 1 , additionally comprising an exhaust system, the cooling system including an exhaust supply passage for supplying cooling fluid to a cooling jacket of the exhaust system.  
     
     
         7 . A method of cooling a watercraft engine having an engine body comprising providing a cooling system to deliver a supply of cooling fluid to a water jacket of the engine body, detecting a temperature of the cooling fluid downstream from the water jacket with a thermostat and substantially preventing cooling water from evacuating the water jacket if the temperature is below a predetermined threshold, detecting a pressure of the cooling fluid upstream from the thermostat and allowing at least a portion of the cooling fluid to bypass the thermostat if the pressure is above a predetermined threshold, the predetermined threshold being a pressure lower than a blow-by pressure of the temperature actuated valve.  
     
     
         8 . The method of  claim 7 , wherein the detection of the cooling fluid pressure takes place upstream from the water jacket and the cooling water additionally bypasses the water jacket if the pressure is above the predetermined threshold.  
     
     
         9 . The method of  claim 7 , additionally comprising providing a supply of fluid to one of an exhaust cooling system and a lubrication cooling system independently from the supply of cooling fluid to the engine body.  
     
     
         10 . A marine engine comprising an engine body defining at least one combustion chamber, a cooling jacket at least partially surrounding the at least one combustion chamber, a cooling system in fluid communication with the cooling jacket, the cooling system supplying cooling fluid to the cooling jacket and comprising a pressure actuated valve and a temperature actuated valve, the pressure actuated valve being upstream from the temperature actuated valve and configured to permit the cooling fluid to bypass the temperature actuated valve if a pressure of the cooling fluid is above a predetermined threshold, the predetermined threshold being a pressure lower than a blow-by pressure of the temperature actuated valve.  
     
     
         11 . The marine engine of  claim 10 , wherein the cooling jacket is positioned between the pressure actuated valve and the temperature actuated valve and the pressure actuated valve is configured to permit the cooling fluid to additionally bypass the cooling jacket.  
     
     
         12 . The small watercraft of  claim 10 , wherein the temperature actuated valve substantially prevents cooling fluid to from exiting the engine body when the cooling fluid within the cooling jacket is below a predetermined temperature.  
     
     
         13 . The small watercraft of  claim 12 , wherein the predetermined temperature is about 50 degrees centigrade.  
     
     
         14 . The small watercraft of  claim 10 , additionally comprising a lubrication system including a lubricant reservoir, the cooling system comprising a reservoir supply passage for supplying cooling fluid to a cooling jacket of the reservoir independently of the engine.  
     
     
         15 . The small watercraft of  claim 10 , additionally comprising an exhaust system, the cooling system including an exhaust supply passage for supplying cooling fluid to a cooling jacket of the exhaust system.