The exhaust manifold is the most important part of the engine exhaust system

The exhaust manifold is the most important part of the exhaust system of the engine , the engine is in the middle of the engine exhaust system and the subsequent coupling hub. Since the cylinder head and the engine is directly connected , in the role of high-temperature exhaust gas discharged from the engine , the larger the impact hot exhaust manifold . The complex structure of the exhaust manifold and the temperature distribution is uneven, has long been under the joint action of  Instrument manifolds  and alternating stresses , easily lead to heat crack initiation and expansion , and with the requirements of lightweight vehicles , many of the exhaust manifold by thin-walled tube made ​​. Therefore, in the design and development process of the exhaust manifold , an important guiding significance for its thermal load research . First, based on the engine parameters and  Stainless steel needle valve layout assembly, 3D modeling software application to establish a model of a gasoline engine exhaust manifold . Secondly , the United CFD simulation software and FEA analysis software to predict the exhaust manifold at rated conditions of temperature field, thermal stress and deformation. Finally, the simulation engine in the normal operation state and stop the cooling cycle two , an equivalent plastic strain as the reference standard , the reliability evaluation manifold . The results show that the exhaust manifold is closely related to the complexity of the conditions of temperature distribution and heat and exhaust manifold , exhaust manifold heat stress release focused on the stiffness of the weak structure transition region.