COOLING METHOD FOR EXHAUST VALVE FOR INTERNAL COMBUSTION ENGINE

PURPOSE:To improve the cooling effect of an exhaust valve with the simple constitution by supplying the coolant introduced into a coolant storing chamber by one movement of the exhaust valve which moves in reciprocation into the exhaust valve by the other movement of the exhaust valve and discharging said coolant into a discharge passage. CONSTITUTION:An exhaust valve 1 is lowered through a piston 11 by supplying the pressurized oil from a hydrauic driving mechanism P into the cylinder chamber 9 of a pump case 7, and set at an exhaust position. In this case, the air in an air compression chamber 16 is compress by a piston 14 lowered integrally with the valve rod 2 of the exhaust valve 1, and the exhaust valve 1 is raised towards a valve closing position from the exhaust position by the compressed air, at the time point when the pressurized oil in the cylinder chamber 9 is discharged. During this rising movement, the coolant in a coolant storing chamber 20 is pressurized oil by the upper surface or a piston 17, and supplied into an annular coolant feeding hole 33 in a valve bevelled part 3 through a coolant feeding hole 21 in the valve rod 2, and the valve bevelled part 3 is cooled by the evaporation of the coolant, and the evaporated coolant is discharged into a discharge passage 6 from an exhaust hole 34.