Development of Ceramic Coated Exhaust Manifolds for Heavy Duty Diesel Engines
Along with the effort to improve engines for exhaust gas emission reduction and high power performance, the increment of exhaust gas temperature emerged as a new problem causing inner surface oxidation and thermal deformation of exhaust manifolds particularly. Under such circumstance, a novel ceramic coating exhaust manifold has been developed. This coating is composed two layers. The inner layer is oxidation resistant layer of comparably compact structure having same thermal expansion coefficient as the cast iron substrate, and the outer one is thermal insulating layer of very porous structure. These two coating layers have therefore made it possible to withstand the crack and peeling off because of the thermal impact of high temperature exhaust gas and made it applicable to the complex figured inner surface. This newly development coating process shall convert a conventional ductile iron manifold to a superior heat resistant manifold by application of the ceramic coating.