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What is the role of the exhaust manifold? Introduction to the role of the exhaust manifold

  • Time of issue:2021-08-13

What is the role of the exhaust manifold? Introduction to the role of the exhaust manifold

(Summary description)With the development of the times, the car has become a means of transportation that we can often use. Whether it is work in our daily life or traveling in our leisure time, we will think of him for the first time. Since the car is already for us It's very important, and we need to understand him better. Today, I will introduce to you what the function of the exhaust manifold is!

　　Exhaust manifold is connected with the engine cylinder block, and the exhaust gas of each cylinder is collected and guided into the exhaust manifold, with branched pipelines. The main requirement for it is to reduce the exhaust resistance as much as possible and avoid mutual interference between the cylinders. When the exhaust is too concentrated, the cylinders will interfere with each other, that is, when a certain cylinder is exhausted, it happens to encounter the undischarged exhaust gas from other cylinders. In this way, it will increase the resistance of the exhaust, thereby reducing the output of the engine. The solution is to separate the exhaust of each cylinder as much as possible, one branch per cylinder, or one branch for two cylinders, and to lengthen and shape each branch as much as possible-to reduce the mutual influence of the gas in different pipes. In order to reduce exhaust resistance, some racing cars use stainless steel pipes to make exhaust manifolds.

　　In the range of room temperature to working temperature, the material should be as little as possible without phase change or as little as possible. Because the phase change will cause volume changes, causing internal stress or deformation, affecting the performance and life of the product. Therefore, the matrix material is preferably a stable ferrite or austenitic structure. The destruction of cast iron parts working under high temperature conditions is mainly manifested as corrosion under high temperature conditions. After the component phases in the structure are oxidized (such as graphitic carbon), the volume of the oxide is larger than the original volume, causing irreversible expansion of the casting. Compared with the three graphite forms of flake, vermicular, and spherical graphite, spheroidal graphite has the best high temperature resistance. The reason is that during the solidification process of cast iron, flake graphite grows as the leading phase. The graphite in the eutectic group constitutes a continuous branched three-dimensional form. At high temperatures, when oxygen penetrates into the metal, after the graphite is oxidized, a microscopic channel is formed to accelerate the oxidation process. When spheroidal graphite is nucleated, it grows to a certain size and is surrounded by the matrix and exists as an isolated ball. After the graphite ball is oxidized, it will not form a channel, thus weakening the further progress of oxidation. Therefore, the high temperature oxidation resistance of nodular cast iron It is better than other forms of graphite, and the oxidized pores have less influence on the high temperature strength of cast iron than other forms of graphite, and vermicular ink is somewhere in between.

　　 There are many types of heat-resistant and high-temperature resistant metal materials, but due to the complicated shape of the exhaust manifold, the material used to manufacture the exhaust manifold must have good manufacturability, and its cost must meet the needs of mass production in the automotive industry.

  • Time of issue:2021-08-13
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With the development of the times, the car has become a means of transportation that we can often use. Whether it is work in our daily life or traveling in our leisure time, we will think of him for the first time. Since the car is already for us It's very important, and we need to understand him better. Today, I will introduce to you what the function of the exhaust manifold is!

　　Exhaust manifold is connected with the engine cylinder block, and the exhaust gas of each cylinder is collected and guided into the exhaust manifold, with branched pipelines. The main requirement for it is to reduce the exhaust resistance as much as possible and avoid mutual interference between the cylinders. When the exhaust is too concentrated, the cylinders will interfere with each other, that is, when a certain cylinder is exhausted, it happens to encounter the undischarged exhaust gas from other cylinders. In this way, it will increase the resistance of the exhaust, thereby reducing the output of the engine. The solution is to separate the exhaust of each cylinder as much as possible, one branch per cylinder, or one branch for two cylinders, and to lengthen and shape each branch as much as possible-to reduce the mutual influence of the gas in different pipes. In order to reduce exhaust resistance, some racing cars use stainless steel pipes to make exhaust manifolds.

　　In the range of room temperature to working temperature, the material should be as little as possible without phase change or as little as possible. Because the phase change will cause volume changes, causing internal stress or deformation, affecting the performance and life of the product. Therefore, the matrix material is preferably a stable ferrite or austenitic structure. The destruction of cast iron parts working under high temperature conditions is mainly manifested as corrosion under high temperature conditions. After the component phases in the structure are oxidized (such as graphitic carbon), the volume of the oxide is larger than the original volume, causing irreversible expansion of the casting. Compared with the three graphite forms of flake, vermicular, and spherical graphite, spheroidal graphite has the best high temperature resistance. The reason is that during the solidification process of cast iron, flake graphite grows as the leading phase. The graphite in the eutectic group constitutes a continuous branched three-dimensional form. At high temperatures, when oxygen penetrates into the metal, after the graphite is oxidized, a microscopic channel is formed to accelerate the oxidation process. When spheroidal graphite is nucleated, it grows to a certain size and is surrounded by the matrix and exists as an isolated ball. After the graphite ball is oxidized, it will not form a channel, thus weakening the further progress of oxidation. Therefore, the high temperature oxidation resistance of nodular cast iron It is better than other forms of graphite, and the oxidized pores have less influence on the high temperature strength of cast iron than other forms of graphite, and vermicular ink is somewhere in between.

　　 There are many types of heat-resistant and high-temperature resistant metal materials, but due to the complicated shape of the exhaust manifold, the material used to manufacture the exhaust manifold must have good manufacturability, and its cost must meet the needs of mass production in the automotive industry.

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