ENGINE VALVE AND ENGINE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To efficiently transport heat of a valve umbrella part on a valve stem side to improve a cooling property of an engine valve and thereby to elongate service life of an engine and improve reliability thereof, reduce a manufacturing cost of an engine valve, and facilitate treatment of the used engine valve. SOLUTION: In the engine valve 7A, a hollow part 21A is axially extended in the valve stem 7Aa extended from the valve umbrella part 7Ab, and a heat transport medium 23 is sealed in the hollow part 21A. The heat transport medium 23 is substance, such as low-melting-point alloy made by mixing lead with bismuth at the mixing ratio of 45 wt.% to 55 wt.%, having a heat transport capacity, that is, a heat quantity transported from a bottom face of the valve umbrella part 7Ab to a stem end part of the valve stem 7Aa is 3×1010(J*s0.5)/(K*m4) or more when a certain temperature difference is applied between the bottom face of the valve umbrella part 7Ab and the stem end part of the valve stem 7Aa. COPYRIGHT: (C)2011,JPO&INPIT