Personal watercraft

Abstract

Disclosed is a personal watercraft capable of appropriately detecting temperatures of an engine and an exhaust manifold by using one temperature sensor and in particular capable of finding that cooling water flow is stagnant in cooling systems of them based on the detection of the temperatures. The personal watercraft comprises a water-cooled multi-cylinder engine placed in an engine room of a body, an exhaust manifold for gathering an exhaust gas from the engine, the exhaust manifold being cooled by cooling water, and a temperature sensor provided so as to be located downstream of the vicinity of an end of the exhaust manifold that is located downstream in an exhaust gas flow path.

What is claimed is:  
     
         1 . A personal watercraft comprising: 
 a water-cooled engine having an exhaust port;    an exhaust passage connected to the exhaust port, for guiding an exhaust gas from the engine to outside of the watercraft; and    a temperature sensor for detecting temperatures of the engine and the exhaust passage, wherein    the temperature sensor is placed in the exhaust passage.    
     
     
         2 . The personal watercraft according to  claim 1 , wherein the engine has multiple cylinders and a plurality of exhaust ports, and the exhaust passage includes a water-cooled exhaust manifold for gathering the exhaust gas from the plurality of exhaust ports, a muffler provided downstream of the exhaust manifold in an exhaust gas flow path, and a flexible connecting passage interposed between the exhaust manifold and the muffler, for interconnecting the exhaust manifold and the muffler.  
     
     
         3 . The personal watercraft according to  claim 2 , wherein the flexible connecting passage is made of rubber.  
     
     
         4 . The personal watercraft according to  claim 2 , wherein the muffler is a water-cooled muffler.  
     
     
         5 . The personal watercraft according to  claim 2 , wherein the temperature sensor is placed in the vicinity of a portion where the flexible connecting passage is connected to the muffler.  
     
     
         6 . The personal watercraft according to  claim 2 , wherein the temperature sensor is placed in the vicinity of a portion where the exhaust manifold is connected to the flexible connecting passage.  
     
     
         7 . The personal watercraft according to  claim 2 , wherein the exhaust passage further includes an expansion chamber interposed between the exhaust manifold and the flexible connecting passage, for interconnecting the exhaust manifold and the flexible connecting passage.  
     
     
         8 . The personal watercraft according to  claim 7 , wherein the temperature sensor is placed in the vicinity of a portion where the expansion chamber is connected to the flexible connecting passage.  
     
     
         9 . The personal watercraft according to  claim 7 , wherein the temperature sensor is placed in the vicinity of a portion where the exhaust manifold is connected to the expansion chamber.  
     
     
         10 . The personal watercraft according to  claim 1 , wherein the temperature sensor is partially exposed outside of the exhaust passage.  
     
     
         11 . The personal watercraft according to  claim 1 , further comprising a water-supply mechanism for supplying water to the exhaust gas in the exhaust passage, wherein the water-supply mechanism is adapted to supply water at a portion of the exhaust passage which is located upstream of where the temperature sensor is placed, in the exhaust gas flow path.