ac93ca6a_goya_Shi___Patent_applications__Description
[Patent application number] 20100077983 [Published] 04-01-2010 [Description] 
ENGINE VALVES - The present invention includes an engine valve including a stem portion and a head portion disposed at one end of the stem portion. A heat insulation layer is formed on a surface of the head portion. A heat conductive layer is formed on a surface of the stem portion.
Yamada, Nagoya-Shi - Patent applications