Poppet valve

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 ).

1 . A poppet valve including a head portion formed integrally with one end side of a stem portion, wherein, on the head portion, a heat insulating portion that is positioned on a combustion chamber side and a metal layer that is positioned on a stem portion side and insulates radiation heat are formed. 
     
     
         2 . The poppet valve according to  claim 1 , wherein a hollow portion extending along a head surface is formed in the head portion, a metal layer that insulates radiation heat is formed on a upper end surface of the hollow portion, and a heat insulating portion is formed between the metal layer and a bottom surface of the hollow portion. 
     
     
         3 . The poppet valve according to  claim 1 , wherein a metal layer that insulates radiation heat is formed on a bottom surface of the head portion, and a heat-insulating surface treatment layer is formed on a combustion chamber side of the metal layer that insulates radiation heat. 
     
     
         4 . The poppet valve according to  claim 1 , wherein the metal is selected among aluminum, copper, and an aluminum alloy. 
     
     
         5 . The poppet valve according to  claim 1 , wherein the metal is foil-shaped or sheet shaped. 
     
     
         6 . The poppet valve according to  claim 1 , wherein the metal layer is a coating formed by surface treatment selected among physical vapor deposition (PVD), thermal spraying, and plating. 
     
     
         7 . The poppet valve according to  claim 2 , wherein the metal is selected among aluminum copper, and an aluminum alloy. 
     
     
         8 . The poppet valve according to  claim 3 , wherein the metal is selected among aluminum, copper, and an aluminum alloy. 
     
     
         9 . The poppet valve according to  claim 2 , wherein the metal is foil-shaped or sheet shaped. 
     
     
         10 . The poppet valve according to  claim 3 , wherein the metal is foil-shaped or sheet shaped. 
     
     
         11 . The poppet valve according to  claim 4 , wherein the metal is foil-shaped or sheet shaped. 
     
     
         12 . The poppet valve according to  claim 2 , wherein the metal layer is as coating formed by surface treatment selected among physical vapor deposition (PVD), thermal spraying, and plating.