| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylinder head for an engine equipped with an internal EGR mechanism providing a desired EGR amount while suppressing costs. SOLUTION: A valve seat 72 closing an exhaust port by the seating of an umbrella part 44b of an exhaust valve 44 is provided in the cylinder head, the valve seat 72 is equipped with a valve seat face 72e diametrally expanded as it approaches a combustion chamber 37 so as to closely contact a valve face 44d formed on the umbrella part 44b and a straight hole part 72g extending toward the combustion chamber 37 such that an inner diameter Din is constant from the valve seat face 72e, and a length L of the straight hole 72g is set such that it is the same with a lift amount during the exhaust gas recirculation of the exhaust valve 44 or it becomes approximate to the lift amount. COPYRIGHT: (C)2010,JPO&INPIT
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