【作者】 秦元伟；

【导师】 张力； 石晓东；

【作者基本信息】 重庆大学 ， 车辆工程， 2008， 硕士

【摘要】 配气机构是发动机的重要组成部分。配气机构的设计影响发动机的充气效率以及换气质量,因此对发动机的动力性、燃油经济性、有害排放有较大的影响。配气机构的工作可靠性和噪声直接影响发动机的整机可靠性和噪声。随着发动机性能和排放要求的不断提高,使得配气机构的研制更加迫切。本文以摩托车CG125发动机配气机构为研究对象,对其配气凸轮型线、运动学、动力学等设计原理作了深入研究和分析,在CG125发动机基础上进行优化设计CG125发动机的配气机构,同时对发动机相关系统的优化,使得发动机的中低速扭矩性能比发动机优化前增加10%以上,配以整车油耗降低10%以上,无加任何机外装置达到欧Ⅱ排放标准,满足我国复杂的路况,有良好的动力性和经济环保性。首先在深入研究内燃机配气机构凸轮型线设计理论。其次是配气机构运动学等分析,通过分析与试验确定最佳的配气正时范围,以改善发动机的换气质量、充气效率、外特性和油耗率等。再则建立了CG125发动机配气机构的动力学模型,通过对运动微分方程进行分析和计算,获得了气门的真实的运动规律和受力情况。对比分析了单质量模型和二质量模型,归纳了影响配气系统的主要因素。再则结合专业软件建立配气机构模型并通过对CG125发动机配气机构的分析,针对性地对CG125发动机配气机构进行优化并对比分析,优化设计新型配气凸轮型线,同时下摇臂的变动设计,力求最大时面值优化设计,该凸轮成果已经申报国家实用新型专利。方案设计完成后,按照设计规格制造相应零部件,最后通过零部件单项试验和整发动机试验验证了配气机构改进设计后的发动机性能、整车油耗及欧Ⅱ排放环保性等的影响,新型的配气机构大大改善了发动机的中低速性能,整车油耗有了质的提升,配以整车无加任何机外装置轻松通过欧Ⅱ排放标准。更多还原

【Abstract】 Valve train is one of the important components of a complete engine. The efficiency of charge and exchange are influenced by the design of valve train, accordingly, the power, economics of fuel and harmful emission are affected as well. The liability and noise of engines are impacted by the liability and noise of valve train directly. The research and the development of valve train are becoming urgently due to the increasingly enhanced requirements to engine’s power and emission.The investigation object in this article bases on CG125 motorcycle , further research and analysis job were performed on profiles of cams and design theory of kinematics and dynamics, the valve train of CG125 engine is the prototype for optimizing, the other systems involved were optimized at the same time, the testing results showed more than 10% torque could be reinforced and above 10% fuel could be saved during low- medium speed phases comparing to the prototype engines, the Euro II emission standard could be satisfied easily without any accessory, the other promotion are favourable applicability to rough road, outstanding driving power, prominent economics and friendly to environment.First, the quality of charge, the efficiency of exchange, outer characteristic and specific fuel consumption could be ameliorated by optimal timing diagram which were established by the results of testing and analysis based on research and development of kinematics of valve train and design theory of the profile of cams.Second, the actual motion and force could be acquired by calculation and analysis via movement differential equations based on the model of valve train dynamics which was set up form CG125 engine. After comparing the single-quality model with the double-quality model, the influence factors to valve train could show up, and then combining with the software to set up the valve train model in order to analyze the rationality of valve train of CG125 engine. The analysis data could be adopted for optimizing the design of valve train and max. Time-area value, the cams profiles, the alteration design of inferior rocker arm. This production had applied to nation practicability award. The manufacture of prototype parts had been implemented after the new-design settled. The results of monomial testing to parts and performance testing to engines identified the advance of engine performance during low-medium speed and the reducing of motorcycle’s specific fuel consumption. Using this new type engine for motorcycle could satisfy Euro II emission standard without any stuff.更多还原