Technical Study And Application Of Intake Manifold

With the rapid development of automobile industry, new products and new technology come forth continuously. Engine as the"heart"part of motor vehicle, its properties directly influence the complete vehicle. SAME company produces 4G6 series engines up to now, among them, the new type of 4G69 engine adopts VVT technology, it has much more advantages in properties than that of 4G63 and 4G64 type of engine. Every part and component is crucial to the improvement of overall properties of engine. So it has high demands on properties and percentage of pass of intake manifold– important part of air intake system, to reduce the resistance of intake manifold to the inlet air during operation of engine, to enhance the amount of inlet air, to meet the demands of enhancing engine properties; And also to enhance the manufacturing quality of intake manifold, to reach the goal of reducing the cost.Metal mold and resin coated sand core making are adopted in intake manifold production, the inner surface of intake manifold is rather rough. The structure of 4G69 intake manifold is complicated, and process technology is difficult, especially, it has much higher demands on the roughness of inner surface. How to enhance the inner surface quality of intake manifold in production process, to reduce the harmful effect on the properties of engine; To enhance the percentage of pass, to reduce the cost of production, are the new task we face.This article analyzed the factors that influence the inner surface of intake manifold, experimentally studied the average grain fineness of core sand ASF, chilling effect, process parameters, and tested the engine properties with different test pieces, during trial manufacturing of intake manifold,the main work is as follows:1) Theoretically analyzed the influence of inner surface quality to the engine properties, the inner surface quality of intake manifold influences the inlet air factor, and directly influences the power, torque, and gas consumption rate of engine.2) Analyzed process technology of intake manifold, to determine casting methods; gravity casting, hot core box resin coated sand core making were adopted. To ensure manufacturability, and higher percentage of pass, pouring temperature, mold temperature, mold structure and alloy were adjusted.3) To reach the demand of inner surface roughness of casting, and to improve permeability, experimental studied average grain fineness of core sand and concentration ratio of tree sieves.4) Analyzed metal solidification theory, to strengthen chilling ability, and to enhance feeding capacity. We studied the chill resin coated sand. Experimented on different ratio of chromite sand, chill additive to reduce the porosity defect, and to enhance the inner surface quality,5) Coating the resin coated sand core with graphite coating, analyzed and verified its influence on inner surface roughness and chilling effect on casting.6) Tested engine properties with two different intake manifolds of normal resin coated sand and chill resin coated sand Tested low speed torque value, maximum torque value, maximum output power value and gas consumption rate.Experiment results indicate:1) Found out the value of core sand average grain fineness AFS by experiment, when AFS value is greater than 55, the inner surface roughness can reach 6.3. Production of intake manifold with resin coated sand of average grain fineness of 65- 75.2) Experiment of distribution of permeability and grain size. When three sieve concentration is greater than 90%, and main sieve percentage is greater than 35%, the permeability of core is good. But in production verification, there is porosity in inner surface of casting, and the roughness of inner surface is not uniform.3) Experiment of normal resin coated sand, with **% chromite sand, and with **% chill additive RC-5. When in heating condition, enthalpy change, measure the heat absorption, to find out the chilling ability. With the increase of chromite sand, the chill effect stably enhanced, but hot strength drop greatly. Conclusions with different proportion: the result with **% RC-5 is good, and the hot strength, normal temperature strength is also good, gas evolution value is reasonable. The verification by production, porosity defect drops obviously.4) Graphite coating has chilling effect to some degree, and can decrease the inner surface roughness value, because of the complicated operation, the factors of human are too many, it is proved that the chilling effect is not obvious, and there is not much effect to the percentage of pass of castings. 5) Test of engine properties, the result s are as follows: The torque and power of engine with intake manifold using normal resin coated sand core can't reach the demand of sample engine. The torque, power and gas consumption rate of engine with intake manifold using chill resin coated sand can reach the properties of original sample engine. And also satisfy technical specifications.By comparation, test of engine with intake manifold using chill resin coated sand technology; the power of engine can be heightened by 4.66%.