【作者】 陈浩；

【导师】 杨靖；

【作者基本信息】 湖南大学 ， 动力机械及工程， 2008， 硕士

【摘要】 城市公交车是城市交通的重要组成部分,为了降低城市公交车燃油消耗,提高其经济性,对发动机与城市公交车传动系的匹配问题做了深入的探讨,并对某城市公交车动力传动系统参数进行了全新的优化匹配设计。根据公交车的运行特点,如何保证某些动力性的前提下,最大化的降低公交循环工况的百公里油耗是本文研究的重点。本文首先阐述了动力性、经济性的评价指标,并将这些指标应用到后续的公交车性能评估与比较中。对公交车动力传动系统进行了匹配设计,其中结合了发动机万有特性图,并阐述发动机与行驶功率的匹配原理,仔细的分析比较并初选出两款发动机,之后按照动力性为主要原则设计了传动系参数。以计算机模拟为手段,建立了详细的仿真模型,对装配了初选的两款发动机的公交车进行了动力性和经济性模拟计算,得到了详细的各评价指标,对结果进行了分析,比较了两款发动机的优劣,优选出合适的发动机。说明了传动系参数优化的重要性,阐述了发动机与传动系匹配的原理。将优化设计应用到传动系参数匹配中,将DOE试验技术、计算机仿真和遗传算法结合起来,对传动系参数进行了优化,优化中以动力性为约束,以公交循环工况综合油耗为目标。对优化前后的各项性能指标进行了比较,优化结果使得在保证动力性的前提下(其中部分动力性还得到了提高),降低了循环工况的综合油耗。最后分析了发动机怠速状态对油耗的影响,优化得到最低油耗下的怠速转速。结果表明,本文所阐述的优化匹配理论、采用的优化技术方法是有效的,可以应用到今后的整车开发中去。更多还原

【Abstract】 City bus is the most important part of city transportation system. In order to reduce the fuel consumption of city bus, the matching problem between engine and city bus transmission was deeply discussed. New optimal design of powertrain parameters of city bus was carried out. Base on the cycle characteristic of city bus, how to reduce the fuel consumption in driving cycle with the constraint of power performance is the key point of this study.Evaluation indexes for bus’s power performance and fuel economy were illuminated first and they were used in the comparison of bus performance. Primary parameters design of powetrain was carried out. Match principle between engine and running power was put forward. Base on the engine fuel consumption map, it has choosed two disel engines from four engines and matched the transmission for each one.The detailed bus modeling was established base on the computer simulation and power performance and fuel economy of city bus matched with engine A and engine B were computed. It has analysed the results and compared the performance of two engines. The optimal engine was choosed at last.The importance of optimization for transmission parameters was pointed out. Match principle between engine and transmission was put forward. Optimization theory was applied to the powertrain matching. DOE(Design of Experiment), simulation and GA(Genetic Algorithm) were combined and transmission parameters were optimized for fuel economy of driving cycle with dynamic constraint. Analysis and comparison of bus performance between pre-optimization and after-optimization were carried through. The result shows that fuel consumption of bus driving cycle was reduced and part of power performance was improved. At last, the influence of engine idle speed on fuel consumption of driving cycle was analysed and optimal engine idle speed was found. The study indicated that the optimal matching theory and the optimization method in this paper are effective and they can be applied to development of automobile.更多还原