【作者】 辛荣勤；

【导师】 洪伟； 李朝晖；

【作者基本信息】 吉林大学 ， 动力工程， 2008， 硕士

【摘要】 近年来,我国汽车工业的发展迅速,在全世界汽车领域中占据着越来越重要的地位。汽车及其零部件的开发及制造能力也在不断提高。我公司从98年开始与日本三菱汽车公司合作,一直生产4G6系列发动机,目前正在试制的4G69发动机采用的是可变气门技术,性能比正在生产的4G63、4G64有一定的优势,但还有待于进一步提高。发动机整体性能的提高,每一个部件都至关重要。因此对进气系统的重要部件进气歧管也提出了更高的性能要求和成品率要求,使其在发动机工作过程中起到降低进气阻力,提高充气量的作用,达到提高发动机性能的目的;同时提高进气歧管的制造质量,达到降低成本的目的。本文重点介绍了4G69发动机进气歧管的试制过程,对影响进气歧管内表面影响因素进行了分析,对采用的芯砂平均细度AFS、激冷效果、工艺参数等进行了试验研究,并对不同的试验件进行了发动机性能测试,取得了比较满意的结果。更多还原

【Abstract】 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%.更多还原