| abstract |
Provided is a poppet valve capable of realizing maximum. combustion efficiency all of three heat transfer forms. In a poppet valve including a head portion ( 14 ) formed integrally with one end side of a stem portion ( 12 ), in the head portion ( 14 ), a hollow portion ( 19 ) extending along a head surface ( 24 ) is formed, a metal layer ( 17 ) that insulates. radiation heat is formed on a upper end surface ( 25 ) of the hollow portion ( 19 ), and a heat insulating portion is formed between the metal layer ( 17 ) and a bottom surface of the hollow portion ( 19 ). Among the heat. transfer forms, conduction and convection are insulated by the heat insulating portion, and radiation is insulated by the metal layer ( 17 ). |