Engine including valve geometry relative to bore size

Abstract

An engine assembly may include an engine block defining a cylinder bore, a cylinder head coupled to the engine block, a first intake valve, a fuel injector in communication with the cylinder bore and a spark plug in communication with the cylinder bore. The cylinder bore may define a first diameter. The cylinder head may define a first intake port and a first exhaust port in communication with the cylinder bore. The first intake valve may be located in the first intake port and may define a second diameter at least 35 percent of the first diameter. The fuel injector and the spark plug may be located centrally relative to the cylinder bore.

1 . An engine assembly comprising:
 an engine block defining a cylinder bore defining a first diameter;   a cylinder head coupled to the engine block and defining a first intake port and a first exhaust port in communication with the cylinder bore;   a first intake valve located in the first intake port and defining a second diameter at least 35 percent of the first diameter;   a fuel injector in communication with the cylinder bore and located centrally relative to the cylinder bore; and   a spark plug in communication with the cylinder bore and located centrally relative to the cylinder bore.   
     
     
         2 . The engine assembly of  claim 1 , further comprising a first exhaust valve located in the first exhaust port and defining a third diameter at least 30 percent of the first diameter. 
     
     
         3 . The engine assembly of  claim 2 , further comprising a second intake valve and a second exhaust valve, the cylinder head defining a second intake port and a second exhaust port, the second intake valve being located in the second intake port and defining a fourth diameter at least 35 percent of the first diameter and the second exhaust valve being located in the second exhaust port and defining a fifth diameter at least 30 percent of the first diameter. 
     
     
         4 . The engine assembly of  claim 3 , wherein the first intake port and the second intake port are located on a first radial half of the cylinder bore and the first exhaust port and the second exhaust port are located on a second radial half of the cylinder bore opposite the first radial half, a first line extending radially through a center of the cylinder bore and a center of the first intake valve extends at a first angle of between 40 degrees and 44 degrees relative to a line extending radially across the cylinder bore defining the first radial half and the second radial half when the first intake valve is in a seated position 
     
     
         5 . The engine assembly of  claim 4 , wherein a second line extending radially through the center of the cylinder bore and a center of the first exhaust valve extends at a second angle of between 39 degrees and 43 degrees relative to the line extending radially across the cylinder bore defining the first radial half and the second radial half when the first exhaust valve is in a seated position. 
     
     
         6 . The engine assembly of  claim 2 , wherein the third diameter is at least 32 percent of the first diameter. 
     
     
         7 . The engine assembly of  claim 1 , wherein the first intake valve extends at an angle of between 19 degrees and 21 degrees relative to a sidewall of the cylinder bore. 
     
     
         8 . The engine assembly of  claim 1 , wherein the second diameter is at least 37 percent of the first diameter. 
     
     
         9 . The engine assembly of  claim 1 , wherein the first diameter is less than 80 millimeters. 
     
     
         10 . The engine assembly of  claim 1 , wherein a first radial distance between a center of the cylinder bore and a radially innermost portion of the first intake valve is less than 25 millimeters when the first intake valve is in a seated position. 
     
     
         11 . An engine assembly comprising:
 an engine block defining a cylinder bore defining a first diameter less than 80 millimeters;   a cylinder head coupled to the engine block and defining a first intake port and a first exhaust port in communication with the cylinder bore;   a first intake valve located in the first intake port and defining a second diameter at least 35 percent of the first diameter;   a first exhaust valve located in the first exhaust port and defining a third diameter at least 30 percent of the first diameter;   a fuel injector in communication with the cylinder bore and located centrally relative to the cylinder bore; and   a spark plug in communication with the cylinder bore and located centrally relative to the cylinder bore.   
     
     
         12 . The engine assembly of  claim 11 , further comprising a second intake valve and a second exhaust valve, the cylinder head defines a second intake port and a second exhaust port, the second intake valve being located in the second intake port and defining a fourth diameter at least 35 percent of the first diameter and the second exhaust valve being located in the second exhaust port and defining a fifth diameter at least 30 percent of the first diameter. 
     
     
         13 . The engine assembly of  claim 12 , wherein the first intake port and the second intake port are located on a first radial half of the cylinder bore and the first exhaust port and the second exhaust port are located on a second radial half of the cylinder bore opposite the first radial half, a first line extending radially through a center of the cylinder bore and a center of the first intake port extends at an angle of between 40 degrees and 44 degrees relative to a line extending radially across the cylinder bore defining the first radial half and the second radial half when the first intake valve is in a seated position. 
     
     
         14 . The engine assembly of  claim 13 , wherein a second line extending radially through the center of the cylinder bore and a center of the first exhaust port extends at an angle of between 39 degrees and 43 degrees relative to the line extending radially across the cylinder bore defining the first radial half and the second radial half when the first exhaust valve is in a seated position. 
     
     
         15 . The engine assembly of  claim 11 , wherein the first intake valve extends at an angle of between 19 degrees and 21 degrees relative to a sidewall of the cylinder bore and the first exhaust valve extends at an angle of between 17.5 degrees and 19.5 degrees relative to the sidewall of the cylinder bore. 
     
     
         16 . The engine assembly of  claim 11 , wherein the third diameter is at least 32 percent of the first diameter. 
     
     
         17 . The engine assembly of  claim 16 , wherein the second diameter is at least 37 percent of the first diameter. 
     
     
         18 . The engine assembly of  claim 11 , wherein the first diameter is less than 75 millimeters. 
     
     
         19 . An engine assembly comprising:
 an engine block defining a cylinder bore defining a first diameter less than 80 millimeters;   a cylinder head coupled to the engine block and defining a first intake port, a second intake port, a first exhaust port, and a second exhaust port in communication with the cylinder bore, the first intake port and the second intake port being located on a first radial half of the cylinder bore and the first exhaust port and the second exhaust port being located on a second radial half of the cylinder bore opposite the first radial half;   a first intake valve located in the first intake port and defining a second diameter at least 37 percent of the first diameter, a first line extending radially through a center of the cylinder bore and a center of the first intake valve extends at an angle of between 40 degrees and 44 degrees relative to a line extending radially across the cylinder bore defining the first radial half and the second radial half when the first intake valve is in a seated position;   a first exhaust valve located in the first exhaust port and defining a third diameter at least 32 percent of the first diameter, a second line extending radially through the center of the cylinder bore and a center of the first exhaust valve extends at an angle of between 39 degrees and 43 degrees relative to the line extending radially across the cylinder bore defining the first radial half and the second radial half when the first exhaust valve is in a seated position;   a second intake valve located in the second intake port and defining a fourth diameter at least 37 percent of the first diameter;   a second exhaust valve located in the second exhaust port and defining a fifth diameter at least 32 percent of the first diameter;   a fuel injector in communication with the cylinder bore and located centrally relative to the cylinder bore; and   a spark plug in communication with the cylinder bore and located centrally relative to the cylinder bore.   
     
     
         20 . The engine assembly of  claim 19 , wherein the first diameter is less than 75 millimeters.