Boat propulsion device, boat, and movable body

Abstract

A boat propulsion device includes an engine, an oil pan to store oil to be supplied to the engine, a case to accommodate at least a portion of the oil pan, and a pump to pump cooling water to a cooling water flow path in the boat propulsion device. The cooling water flow path includes a first flow path between the oil pan, the case, and the engine, and a second flow path branching from the first flow path at a location between the oil pan and the case and not extending to the engine. The boat propulsion device further includes a flow rate regulator to change at least one of a flow rate of the cooling water flowing into the first flow path and a flow rate of the cooling water flowing out of the first flow path.

What is claimed is: 
     
         1 . A boat propulsion device comprising:
 an engine;   an oil pan to store oil to be supplied to the engine;   a case to accommodate at least a portion of the oil pan; and   a pump to pump cooling water to a cooling water flow path in the boat propulsion device; wherein   the cooling water flow path includes:
 a first flow path extending between the oil pan, the case, and the engine; and 
 a second flow path branching from the first flow path at a location between the oil pan and the case and not extending to the engine; and 
   the boat propulsion device further comprises a flow rate regulator to change at least one of a flow rate of the cooling water flowing into the first flow path and a flow rate of the cooling water flowing out of the first flow path.   
     
     
         2 . The boat propulsion device according to  claim 1 , further comprising:
 at least one temperature sensor to measure one of a temperature in a vicinity of a combustion chamber of the engine, a temperature of an exhaust pipe through which exhaust gas discharged from the combustion chamber flows, a temperature of the oil, or a temperature of the cooling water.   
     
     
         3 . The boat propulsion device according to  claim 2 , further comprising:
 a controller configured or programmed to control the flow rate regulator to:
 set the flow rate of the cooling water flowing into the first flow path to a first flow rate when the temperature measured by the at least one temperature sensor is less than a predetermined value; and 
 set the flow rate of the cooling water flowing into the first flow path to a second flow rate, which is higher than the first flow rate, when the temperature measured by the at least one temperature sensor is equal to or more than the predetermined value. 
   
     
     
         4 . The boat propulsion device according to  claim 2 , further comprising:
 a controller configured or programmed, in an idle state of the boat propulsion device, to:
 switch a rotation speed of the engine to a first speed when the temperature measured by the at least one temperature sensor is less than a predetermined value; and 
 switch the rotation speed of the engine to a second speed, which is slower than the first speed, when the temperature measured by the at least one temperature sensor is equal to or more than the predetermined value. 
   
     
     
         5 . The boat propulsion device according to  claim 2 , wherein the at least one temperature sensor includes:
 a first temperature sensor to measure the temperature in the vicinity of the combustion chamber;   a second temperature sensor to measure the temperature of the exhaust pipe;   a third temperature sensor to measure the temperature of the oil; and   a fourth temperature sensor to measure the temperature of the cooling water.   
     
     
         6 . The boat propulsion device according to  claim 5 , further comprising:
 a controller configured or programmed to control the flow rate regulator to:
 set the flow rate of the cooling water flowing into the first flow path to a first flow rate when the temperatures measured by the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor are each less than a predetermined value; and 
 set the flow rate of the cooling water flowing into the first flow path to a second flow rate, which is higher than the first flow rate, when the temperature measured by any of the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor is equal to or greater than the predetermined value. 
   
     
     
         7 . The boat propulsion device according to  claim 5 , further comprising:
 a controller configured or programmed, in an idle state of the boat propulsion device, to:
 switch a rotation speed of the engine to a first speed when the temperatures measured by the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor are each less than a predetermined value; and 
 switch the rotation speed of the engine to a second speed, which is slower than the first speed, when the temperature measured by any of the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor is equal to or greater than the predetermined value. 
   
     
     
         8 . The boat propulsion device according to  claim 1 , wherein
 the oil pan is located higher than the pump; and   the engine is located higher than the oil pan.   
     
     
         9 . The boat propulsion device according to  claim 8 , wherein
 the first flow path and the second flow path branch at a height lower than a lower end of the oil pan.   
     
     
         10 . The boat propulsion device according to  claim 1 , wherein the flow rate regulator includes a valve. 
     
     
         11 . The boat propulsion device according to  claim 10 , wherein the valve is adjustable to any valve opening degree from 0% to 100%. 
     
     
         12 . The boat propulsion device according to  claim 10 , wherein the valve is located outside the case. 
     
     
         13 . The boat propulsion device according to  claim 10 , wherein
 the valve is a three-way valve and is located inside the case;   the second flow path extends downwardly in the boat propulsion device from a connection position with the valve; and   an outlet of the second flow path is located at a lower portion of the boat propulsion device.   
     
     
         14 . The boat propulsion device according to  claim 10 , further comprising:
 a device to be cooled by the cooling water; wherein   the valve is a three-way valve and is located inside the case; and   the second flow path extends around the device.   
     
     
         15 . The boat propulsion device according to  claim 1 , wherein the first flow path contacts the oil pan. 
     
     
         16 . The boat propulsion device according to  claim 1 , wherein the first flow path extends around the engine and then between the oil pan and the case. 
     
     
         17 . The boat propulsion device according to  claim 1 , further comprising:
 an exhaust pipe located adjacent to the oil pan and through which exhaust gas discharged from the engine flows.   
     
     
         18 . A boat comprising:
 a hull; and   the boat propulsion device according to  claim 1  mounted at a rear of the hull.   
     
     
         19 . A movable body comprising:
 an engine; and   an oil pan to store oil to be supplied to the engine;   a case to accommodate at least a portion of the oil pan; and   a pump to pump cooling water to a cooling water flow path in the movable body; wherein   the cooling water flow path includes:
 a first flow path extending between the oil pan, the case, and the engine; and 
 a second flow path branching from the first flow path at a location between the oil pan and the case and not extending to the engine; and 
   the movable body further comprises a flow rate regulator to change at least one of a flow rate of the cooling water flowing into the first flow path and a flow rate of the cooling water flowing out of the first flow path.