CYLINDER HEAD OF PARTIALLY LIQUID-COOLED TYPE AIR-COOLED ENGINE

摘要

PURPOSE:To facilitate the discharge of casting sand by forming a liquid-cooled chamber into an annular form surrounding a subcombustion chamber and forming a casting sand discharging hole onto the part close to the peripheral surface of the cylinder head on the peripheral wall, in the constitution in which a liquid-cooled chamber is formed in the formation part of the subcombustion chamber of the cylinder head. CONSTITUTION:An oil jacket 5 is formed in concentric form to a subcombustion chamber 3 onto the inner wall 4 of a cylinder head 2 in the peripheral part of the subcombustion chamber 3 formed on the cylinder head 2, and said oil jacket 5 is formed from a core made of casting sand during the casting of the cylinder head 2. Said core is supported through a core supporting tool from the peripheral surface 6 side of the cylinder head 2. The vacant space formed by the removal of the core supporting tool after casting is used as a casting sand discharging hole 7, and the casting sand in the oil jacket part 5 is discharged. Further, an auxiliary hole 13 for discharging the casting sand is formed between a fuel injection nozzle 9 arrangement part and the fixed part of a valve arm chamber cover 12, on the outer edge wall 11 of the oil jacket 5, and the casting sand can be discharged surely.