I. Material Selection: Most domestic professional cylinder head materials use EL101 aluminum-silicon alloy. This material has a small specific gravity, high strength, good casting fluidity, and is suitable for casting complex shape castings, especially with high thermal conductivity. It can reduce the temperature of the heated part of the automobile cylinder head and ensure the thermal strength of the automobile cylinder head. However, the disadvantage of this material is that the elastic modulus is low, it is easy to produce plastic deformation, and the price is more expensive.
Structure type: The cylinder head of the car is a block cylinder head with four cylinders and one head. This structure can reduce the cylinder center distance, facilitate the arrangement of the intake and exhaust channels, and the water channel is relatively simple. However, due to the large length of the block-shaped automobile cylinder head, the longitudinal rigidity is insufficient, and warpage and deformation are easy to occur during work and assembly. In order to compensate for the lack of longitudinal rigidity, the upper surface of the automobile cylinder head adopts a box-type structure. With this structure, the height of the automobile cylinder head does not increase much, but its stiffness and strength are improved.
3. Intake and exhaust ducts: The intake and exhaust ducts of the cylinder head of the car are each on the side of the cylinder head. Each cylinder has one inlet and one exhaust, and they are all straight. This kind of airway has small resistance, and the flow velocity of the intake and exhaust is quite high, especially the intake port, the throat velocity is extremely fast and extremely high. Therefore, the geometry, size, cross-sectional area, and roughness of the intake and exhaust ducts have a great impact on the power and economy of the engine. Therefore, when casting this type of automobile cylinder head, strict requirements should be made.
Fourth, water channel layout: The water channel layout can effectively ensure that the heated parts of the automobile cylinder head have achieved preferential cooling. Due to the use of multi-ball combustion chambers and straight air passages, the cooling water cavity is relatively unobstructed. Around each combustion chamber, there is cooling water introduced from the cylinder block for cooling, and there is a cooling water cavity around the exhaust duct and spark plug installation. Practice has proved that this arrangement of the cooling water cavity is reliable, and no enthusiasm in the area of the exhaust valve seat hole and the nose of the spark plug is found. Of course, this is also inseparable from the use of aluminum alloy materials with good thermal conductivity.