Cylinder head with coolant passage passing around outside of cylinder head fixing bolt boss and directing coolant flow toward squish area cooling passage portion

For an internal combustion engine of an automotive vehicle, comprising a cylinder block formed with a first cylinder bore and a second cylinder bore, and first and second pistons respectively fitted in said first cylinder bore and said second cylinder bore and reciprocating therein:

• a cylinder head for affixment to said cylinder block and for defining a first combustion chamber and a second combustion chamber by first and second portions of said cylinder head in cooperation respectively with said first piston and said first cylinder bore, and said second piston and said second cylinder bore, formed with:
• (a) a portion which in cooperation with a portion of said first piston defines a squish area of said first combustion chamber;
• (b) a cylinder fixing bolt hole boss between said first portion of said cylinder head which defines said first combustion chamber and said second portion of said cylinder head which defines said second combustion chamber and disposed towards the side of said cylinder head on the side of said squish area;
• (c) a side wall defining one side of a coolant passage which substantially follows through said cylinder head proximate to said squish area so that a first portion of said coolant passage directly cools said squish area;
• (d) a second portion of said coolant passage passing around said cylinder fixing bolt hole boss at least between it and said side wall of said cylinder head;
• (e) said second coolant passage portion directing flow of coolant therethrough to said first coolant passage portion.