乘用车城市行驶工况构建方法研究

Study on Construction Method of Urban Driving Cycle of Passenger Vehicles

本研究针对国内具体城市实际交通环境的乘用车行驶工况的构建方法,以西安市为研究对象构建了西安市电动汽车城市循环工况。首先根据西安市城市交通环境的实际特征,结合道路长度、道路等级、各等级道路车流量等信息采用参数估计的方法来确定随机抽样中西安市道路必要样本容量,构建出驾驶人最佳出行方式模型依据层次分析法求得各类道路比例,设计出循环工况试验路线;依照相关试验理论设计了采样方法与采样时间,选取了一款城市保有量较多的纯电动乘用车辆进行实际的道路试验。为采集到各种交通状况下的车辆运行数据,采样时间覆盖每天早高峰、晚高峰、低谷期等有特殊交通流量的时段,同时为避免单天试验因天气、交通事故等不定因素对试验结果造成的影响,试验过程连续多天进行采集。随后对数据进行预处理、片段划分、利用主成分分析法对数据进行降维以及利用SPSS软件对降维后的试验数据进行聚类处理,并针对传统马尔科夫方法构建工况其分类条件单一及小概率事件丢失的问题,提出一种利用蒙特卡洛模拟进行优化的方法。最终完成西安市乘用车行驶工况的构建,与短行程法、V-A矩阵法和定步长法构建的工况相比,使用本研究的方法建立的工况精度较高;与各类标准工况相比,使用本研究方法建立的工况更符合西安市的实际情况。

Aiming at the construction method of passenger vehicle driving cycle in the actual traffic environment of specific cities in China,taking Xi’an City as the research object,the urban driving cycle of electric vehicles in Xi’an City is constructed.First,according to the actual characteristics of urban traffic environment in Xi’an City,the necessary sample size of the roads in Xi’an City in random sampling is determined by parameter estimation method based on the information of road length,road grade and traffic volume of each grade.The model of driver’s optimal travel mode is constructed,and the proportion of roads in each grade is calculated by analytic hierarchy process(AHP),and the test route of the driving cycle is designed.According to the relevant experimental theory,the sampling method and sampling time are designed,and a pure electric passenger vehicle with a large ownership is selected for actual road test.In order to collect the vehicle operation data under different traffic conditions,the sampling time covers the periods of special traffic volume such as morning peak,night peak and midday valley.Meanwhile,in order to avoid the influence of uncertain factors such as weather and traffic accidents on the test result of discontinuous days,the data of the test process are collected during consecutive days.Then,the raw data are preprocessed,fragmented,dimensionality reduced by principal component analysis(PCA)and clustered through SPSS software.Moreover,in view of the single classification condition and the loss of small probability events in constructing driving cycle by traditional Markov method,a Monte Carlo simulation optimization method is proposed.Finally,the construction of the driving cycle of passenger vehicles in Xi’an City is completed.The result shows that(1)compared with the driving cycles built by short trip method,V-A matrix method and constant step cutting method,the driving cycle established by the proposed method is relatively accurate;(2)compared with various standard driving cycles,the Xi’an driving cycle established by the proposed method conforms to actual situation better.