Patent ID: 8051810

Claim:
A cylinder head having a coolant passage therein, comprising: a coolant inlet; a plurality of exhaust valve seat portions disposed near the coolant inlet; a spark plug mounting portion disposed near the exhaust valve seat portions and formed substantially in a center portion of the cylinder head in a longitudinal direction thereof; a guide rib protruding from an inner circumference of the cylinder head and configured to be close to the exhaust valve seat portions for coolant to flow near the exhaust valve seat portions and the spark plug mounting portion, and a plurality of intake valve seat portions disposed opposite the exhaust valve seat portions with respect to the spark plug mounting portion; wherein the guide rib is disposed near an end of the coolant inlet and extends toward the spark plug mounting portion; wherein the guide rib is disposed between a center line connecting the exhaust valve seat portions and the inner circumference of the cylinder head; and wherein a coolant outlet is disposed between a center line of the intake valve seat portions and inner circumference of the cylinder head.