Watercraft Having a Four Stroke Engine with a Supercharger

Abstract

A personal watercraft is disclosed with a hull, a seating assembly, and a four stroke internal combustion engine below the seating assembly. The engine has at least one intake valve for each of the combustion cylinder chambers, at least one exhaust valve for each of the combustion cylinder chambers, and a valve actuation assembly located in a cylinder head for operating the intake and exhaust valves. At least one air intake passageway is operatively coupled to the combustion cylinder chambers through the intake valves. An air intake manifold is connected to the cylinder bead and operatively connected to the at least one air intake passageway. The engine also has a supercharger for boosting air to the air intake manifold. The watercraft also includes a propulsion unit, operatively coupled to the crankshaft, which is located on one end of the two ends of the crankcase.

1 . A personal watercraft comprising: 
 a hull;    a deck disposed on the hull;    an engine compartment defined between the hull and the deck;    a four stroke internal combustion engine disposed in the engine compartment, the engine comprising: 
 a crankcase having a top, a bottom, two sides, and two ends, the crankcase being separable along a plane defining an upper crankcase and a lower crankcase, the plane being disposed at an angle from horizontal when viewed from one of the ends of the crankcase;  
 a crankshaft rotatably mounted in the crankcase between the two ends;  
 a balance shaft rotatably mounted in the crankcase between the two ends parallel to the crankshaft,  
 the crankshaft and the balance shaft being disposed in the plane such that the balance shaft is vertically higher on the crankcase than the crankshaft;  
 a cylinder head housing operatively connected to the top of the crankcase,  
 the crankcase and the cylinder head housing forming at least one combustion chamber therebetween;  
 at least one intake valve for the at least one combustion chamber;  
 at least one exhaust valve for the at least one combustion chamber;  
 a valve actuation assembly located in the cylinder head housing for actuating the at least one intake valve and the at least one exhaust valve; and  
 at least one air intake passageway fluidly connected to the at least one combustion chamber;  
   a propulsion unit operatively coupled to the crankshaft; and    at least one air intake manifold fluidly connected to the at least one air intake passageway.    
   
   
       2 . The personal watercraft of  claim 1 , wherein the at least one combustion chamber is disposed at an angle from vertical when viewed from one of the ends of the crankcase.  
   
   
       3 . The personal watercraft of  claim 2 , wherein the at least one air intake manifold has a central passage; 
 wherein a line extending from a centre of the crankshaft to a centre of the central passage is disposed at an angle from vertical when viewed from one of the ends of the crankcase; and    wherein the line and the at least one combustion chamber form a “V” when viewed from one of the ends of the crankcase.    
   
   
       4 . The personal watercraft of  claim 1 , wherein the at least one air intake manifold has a central passage.  
   
   
       5 . The personal watercraft of  claim 4 , further comprising a flame arrester disposed in the central passageway.  
   
   
       6 . The personal watercraft of  claim 1 , further comprising a supercharger for boosting air to the at least one air intake manifold fluid connected with the at least one air intake manifold.  
   
   
       7 . The personal watercraft of  claim 6 , wherein the supercharger has a blower drive shaft disposed outside the plane.  
   
   
       8 . The personal watercraft of  claim 7 , wherein the blower drive shaft is disposed above the plane.  
   
   
       9 . The personal watercraft of  claim 6 , wherein the supercharger is a mechanically driven supercharger.  
   
   
       10 . The personal watercraft of  claim 9 , wherein the supercharger is operatively driven by the crankshaft.  
   
   
       11 . The personal watercraft of  claim 1 , further comprising at least one exhaust passageway fluidly connected to the at least one combustion chamber; and 
 an exhaust manifold fluidly connected to the at least one exhaust passageway.    
   
   
       12 . The personal watercraft of  claim 11 , wherein the valve actuation assembly has a camshaft; 
 wherein a line extending from a centre of the crankshaft to a centre of the camshaft is disposed at an angle from vertical when viewed from one of the ends of the crankcase; and    wherein the at least one air intake manifold is disposed above the line and the exhaust manifold is disposed below the line.    
   
   
       13 . The personal watercraft of  claim 1 , wherein the upper crankcase is fastened to the lower crankcase.  
   
   
       14 . The personal watercraft of  claim 1 , wherein the crankshaft is disposed horizontally.  
   
   
       15 . The personal watercraft of  claim 1 , wherein the at least one combustion chamber is three combustion chambers.  
   
   
       16 . The personal watercraft of  claim 15 , wherein the three combustion chambers are disposed in line between the two ends of the crankcase.  
   
   
       17 . The personal watercraft of  claim 16 , wherein the three combustion chambers are disposed at an angle from vertical when viewed from one of the ends of the crankcase.  
   
   
       18 . The personal watercraft of  claim 1 , wherein the at least one intake valve for the at least one combustion chamber is two intake valves for the at least one combustion chamber; and 
 wherein the at least one exhaust valve for the at least one combustion chamber is two exhaust valves for the at least one combustion chamber.    
   
   
       19 . The personal watercraft of  claim 1 , further comprising an oil pump and a coolant pump assembly, at least one of the oil pump and the coolant pump assembly being operatively driven by the balance shaft.  
   
   
       20 . The personal watercraft of  claim 19 , further comprising a connecting shaft driving at least one of the oil pump and the coolant pump assembly, the connecting shaft being coaxial with the balance shaft.