Vessel propulsion apparatus, vessel, and vessel engine

Abstract

A vessel propulsion apparatus includes an engine and a propulsion unit to be driven by the engine. The engine includes a cylinder head including a combustion chamber and a pair of intake openings to communicate with the combustion chamber. The engine further includes a pair of intake ports respectively including a pair of downstream portions respectively connected to the pair of intake openings. A distance between the pair of downstream portions decreases toward the pair of intake openings.

What is claimed is: 
     
         1 . A vessel propulsion apparatus comprising:
 an engine including a cylinder head including a combustion chamber, a pair of intake openings to communicate with the combustion chamber, and a pair of intake ports respectively including a pair of downstream portions respectively connected to the pair of intake openings; and   a propulsion unit to be driven by the engine; wherein   a distance between the pair of downstream portions decreases toward the pair of intake openings.   
     
     
         2 . The vessel propulsion apparatus according to  claim 1 , further comprising:
 a pressure charger and an intercooler to cool air compressed by the pressure charger; wherein   air cooled by the intercooler flows into the pair of intake ports; and   the pair of intake ports include a pair of independent intake ports that individually extend from the intercooler to the pair of intake openings.   
     
     
         3 . A vessel propulsion apparatus comprising:
 an engine including a cylinder head including:
 a combustion chamber; 
 a pair of intake openings to communicate with the combustion chamber; 
 a pair of inner surfaces respectively extending from peripheral edges of the pair of intake openings, facing each other in an arrangement direction in which the pair of intake openings are arranged, and defining the combustion chamber therebetween; and 
 a pair of intake ports respectively connected to the pair of intake openings; and 
   a propulsion unit to be driven by the engine; wherein   the pair of inner surfaces include a pair of upstream portions respectively connected to the peripheral edges of the pair of intake openings, and a distance between the pair of upstream portions decreases in a direction moving away from the peripheral edges of the pair of intake openings.   
     
     
         4 . The vessel propulsion apparatus according to  claim 3 , wherein
 the cylinder head includes a pair of exhaust openings to communicate with the combustion chamber and arranged side by side along the arrangement direction;   the engine includes a pair of exhaust ports respectively connected to the pair of exhaust openings;   a first inner surface of the pair of inner surfaces connects a peripheral edge of a first intake opening of the pair of intake openings and a peripheral edge of a first exhaust opening of the pair of exhaust openings;   a second inner surface of the pair of inner surfaces connects a peripheral edge of a second intake opening of the pair of intake openings and a peripheral edge of a second exhaust opening of the pair of exhaust openings; and   the first inner surface and the second inner surface are curved toward each other.   
     
     
         5 . The vessel propulsion apparatus according to  claim 1 , wherein
 the engine includes a crankshaft extending in a vertical direction; and   the vessel propulsion apparatus is an outboard motor including a drive shaft joined to the crankshaft and extending in the vertical direction, a propeller shaft extending along a horizontal direction, a propeller defining the propulsion unit joined to the propeller shaft, and a transmission to transmit rotation of the drive shaft to the propeller shaft.   
     
     
         6 . A vessel comprising:
 a hull; and   the vessel propulsion apparatus according to  claim 1  mounted to the hull to provide a thrust to the hull.   
     
     
         7 . A vessel engine comprising:
 a cylinder head including a combustion chamber and a pair of intake openings to communicate with the combustion chamber; and   a pair of intake ports respectively connected to the pair of intake openings; wherein   the pair of intake ports include a pair of downstream portions respectively connected to the pair of intake openings, and a distance between the pair of downstream portions decreases toward the pair of intake openings.   
     
     
         8 . A vessel engine comprising:
 a cylinder head including:
 a combustion chamber; 
 a pair of intake openings to communicate with the combustion chamber; 
 a pair of inner surfaces that respectively extend from peripheral edges of the pair of intake openings, that face each other in an arrangement direction in which the pair of intake openings are arranged, and that define the combustion chamber therebetween; and 
 a pair of intake ports respectively connected to the pair of intake openings; wherein 
   the pair of inner surfaces include a pair of upstream portions respectively connected to the peripheral edges of the pair of intake openings, and a distance between the pair of upstream portions decreases in a direction moving away from the peripheral edges of the pair of intake openings.