Because the cylinder block and the cylinder head cannot be absolutely flat, it is necessary to have a cylinder head gasket to prevent high-pressure gas, lubricating oil and cooling water from escaping between them.
There are usually two types of cylinder head gaskets:
(1) asbestos-based asbestos pad coated with copper or steel. Some use braided steel wire or rolled steel plate as skeleton, and some add metal rings around the cylinder hole to improve strength. The advantage is low price, but poor strength. Asbestos has been discontinued in developed countries because of its carcinogenic effect on human body.
(2) The metal pad is made of a single polished steel plate with an elastic ridge at the sealing position, which is sealed by the elasticity of the ridge and the function of heat-resistant sealant. It has been widely used abroad. It has the advantages of high strength and good sealing effect, but the cost is high.
Asbestos-free gaskets are suitable for all types of gasoline and diesel engines, especially for after-tightening systems.
Metal cylinder gasket is suitable for high temperature, high pressure, air tightness, water tightness and oil tightness connection of various automobile engines, and its comprehensive technical performance index is higher than that of asbestos cylinder gasket and asbestos-free cylinder gasket, which is the development direction of sealing products in the future.
Its structure is composed of an upper cover plate, a core plate and a lower cover plate, and it is characterized in that line sealing is realized through convex rings on the upper cover plate, the lower cover plate and the core plate.
Metal cylinder gasket core plate: low carbon steel material, stamped with sealing convex ring, and coated with rubber after surface treatment. The function of sealing ring is to strengthen the strength of combustion chamber cylinder mouth and resist the impact of high temperature and high pressure. The core coating is used to compensate the roughness of the cover plate.
Upper and lower cover plates on the metal cylinder gasket core plate: the upper and lower cover plates with convex rings are stamped from stainless steel with rubber coating on the surface. The convex ring is divided into half rib and full rib. The function is to seal the waterway and oil circuit. The coating is used to compensate the roughness of the cylinder head.