Understanding the combustion behavior of electric bicycle batteries and unveiling its relationship with fire extinguishing

In this study,a detailed analysis of the combustion behaviors of the lithium iron phosphate(LFP)and lithium manganese oxide(LMO)batteries used in electric bicycles was conducted.This research included quantitative measurements of the combustion duration,flame height,combustion temperature,heat release rate,and total heat release.The results indicated that LMO batteries exhibited higher combustion temperatures of 600–700°C,flame heights of 70–75 cm,a significantly higher heat release rate of40.1 k W(12 Ah),and a total heat release of 1.04 MJ(12 Ah)compared to LFP batteries with the same capacity.Based on these experimental results,a normalized total heat release(NORTHR)parameter was proposed,demonstrating good universality for batteries with different capacities.Utilizing this parameter,quantitative calculations and optimization of the extinguishing agent dosage were conducted for fires involving these two types of batteries,and the method was validated by extinguishing fires for these two types of battery packs with water-based extinguishing fluids.

Research on Planning and Design of Multi-Story Prefabricated Electric Bicycle Charging Parking Lot in Urban and Rural Areas

In recent years,disorderly parking and difficult charging of electric bicycles have been challenges in urban management.The rapid growth of electric bicycles is in contradiction with the lack of dedicated parking spaces and charging service facilities in towns and villages.To solve the issue of parking and charging electric bicycles in limited urban and rural spaces,prefabricated building technology is applied to the design of a multi-story electric bicycle parking lot.The multi-story prefabricated electric bicycle parking lot is utilized in urban and rural planning and design to upgrade parking facilities in old urban areas,land-constrained commercial areas,as well as counties,towns,and rural areas with inadequate municipal facilities.Multi-story prefabricated electric bicycle parking lots are the application exploration of industrial buildings,and promote the high-quality development planning and construction of towns and counties and villages.Compared with the single-story metal charging station,the multi-story assembled electric bicycle parking lot has the characteristics of integrating parking and charging,being more durable and safer in structure,accommodating a large number of vehicles,and improving the space utilization rate.

Reconstruction of Car-Electric Bicycle Side Collision Based on PC-Crash

A collision model, an automobile model and a multi-rigid-body model in PC-crash are analyzed. By simulating a side collision accident between a car and an electric bicycle (EB), a method that reproduces the car-electric bicycle side collision accident based on PC-crash is presented according to some important information such as the final position, the contacting location between the cyclist and the car. A result is obtained by comparing with the reproduced result, the deformation of accident vehicle and the surveillance video. The rollover direction and fells-over sliding direction after the collision and the contacting location and wrap motion of cyclist and electric bicycle are fitting in with the real situation better compared with the reconstruction result in PC-crash. Then the responsive-surface method and MONTEKARLO method are used in MATLAB to analyze the uncertainty of the vehicle speed in reproduced scene results. And the range of values of the pre-collision speed is obtained which makes the reproduced result more objective and convincible that could provide the basis of the accident assessment.

Campus Mobility for the Future: The Electric Bicycle

Sustainable and practical personal mobility solutions for campus environments have traditionally revolved around the use of bicycles, or provision of pedestrian facilities. However many campus environments also experience traffic congestion, parking difficulties and pollution from fossil-fuelled vehicles. It appears that pedal power alone has not been sufficient to supplant the use of petrol and diesel vehicles to date, and therefore it is opportune to investigate both the reasons behind the continual use of environmentally unfriendly transport, and consider potential solutions. This paper presents the results from a year-long study into electric bicycle effectiveness for a large tropical campus, identifying barriers to bicycle use that can be overcome through the availability of public use electric bicycles.

Development of the zinc-air power battery on electric bicycles in China

Electric bicycles powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection policy of the lead-acid battery, the zinc-air power battery was proposed to solve the problem in this paper. The advantage and the feasibility of developing zinc-air power batteries in China have been illustrated in the paper. And, it is represented that development of electric bicycles powered by the zinc-air power battery also can accelerate this kind of battery's development in other electric vehicles, which is favorable to economic development and environmental protection.

Improved YOLOv8n Model for Detecting Helmets and License Plates on Electric Bicycles

Wearing helmetswhile riding electric bicycles can significantly reduce head injuries resulting fromtraffic accidents.To effectively monitor compliance,the utilization of target detection algorithms through traffic cameras plays a vital role in identifying helmet usage by electric bicycle riders and recognizing license plates on electric bicycles.However,manual enforcement by traffic police is time-consuming and labor-intensive.Traditional methods face challenges in accurately identifying small targets such as helmets and license plates using deep learning techniques.This paper proposes an enhanced model for detecting helmets and license plates on electric bicycles,addressing these challenges.The proposedmodel improves uponYOLOv8n by deepening the network structure,incorporating weighted connections,and introducing lightweight convolutional modules.These modifications aim to enhance the precision of small target recognition while reducing the model’s parameters,making it suitable for deployment on low-performance devices in real traffic scenarios.Experimental results demonstrate that the model achieves an mAP@0.5 of 91.8%,showing an 11.5%improvement over the baselinemodel,with a 16.2%reduction in parameters.Additionally,themodel achieves a frames per second(FPS)rate of 58,meeting the accuracy and speed requirements for detection in actual traffic scenarios.

基于TAM-CPV模型的共享电单车持续使用意愿分析

深入剖析共享电单车的使用因素,增强共享电单车用户持续使用意愿对促进共享电单车健康有序发展、提升投放管理精细化水平至关重要。以技术接受模型(technology acceptance model,TAM)为基础,引入感知价值理论(customer perceived value,CPV)中的感知愉悦性、感知风险,并引入感知成本因素;构建基于TAM-CPV模型的共享电单车持续使用意愿模型;以重庆市共享电单车运营的监管数据、现场调查数据和网络调查数据为基础,综合运用SPSS、AMOS软件对结构方程模型开展检验及分析。研究结果表明:感知易用性是影响持续使用意愿的最显著正向因素,感知愉悦性次之,感知成本是唯一负向影响因素;这预示着政府管理部门应当注重共享电单车投放点的合理性,企业应当注重共享电单车APP的使用体验、计费规则。

一种创新型的智能电动车车速提示器

文章对如何提高电动自行车车速检测的准确度进行了研究。一方面对电动自行车驱动电机霍尔信号滤波整形,通过单片机精确计算出信号周期,进而得出准确的电机转速;另一方面针对不同体重的电动自行车驾驶员,对电动自行车车轮产生的压力不同,进而导致轮子实际运行半径的不同,文章采用手动输入车轮半径的方式,使得车轮半径的参数更加精准。以上两个改进措施大大提高了电动自行车车速检测的准确度。当电动车超速时,提示器准确发出超速报警,从而减少交通事故的发生。

外卖配送电动自行车换电柜选址定容实证研究

针对外卖配送电动自行车换电柜布局不合理带来的部分换电柜利用率低与部分换电需求得不到及时满足的供需矛盾问题,本文通过聚类POI(Point of Interest)数据确定外卖配送起止点,并通过仿真模拟外卖骑手配送路径预测外卖配送电动自行车换电需求时空分布,构建换电柜运营商总成本最低和用户满意度最高的多目标换电柜选址定容模型,并以新乡市主城区为例,采用NSGA-II(Non-dominated Sorting Genetic Algorithm II)算法得到换电柜选址定容方案。研究结果表明:仿真模拟得出的换电需求时间分布预测值与实际值基本吻合,换电需求在11:00,14:00,17:00和20:00左右急剧增长,且11:00和14:00左右的换电需求量显著高于17:00和20:00左右的换电需求量,外卖骑手配送路径仿真模拟方法在换电需求预测上具有较高的预测精度;换电柜选址方案不能同时满足运营商和用户利益均为最优,用户满意度的提高需以增加运营商总成本为代价;同时,兼顾运营商和用户利益的新乡市主城区外卖配送电动自行车换电柜最佳建设数量为26,其中,容量为11的换电柜11个,容量为22的换电柜8个,容量为33的换电柜7个;新乡市主城区应按照备选点编号15-7-19-17依次新增换电柜至30个,此时,用户满意度最大,若继续增加换电柜建设数量,只会增加运营商总成本。

基于强制性国标实施视角的电动自行车头盔佩戴行为研究

近年来我国电动自行车事故频发,而在此类事故中是否佩戴头盔以及头盔质量成为对电动车骑乘者减少损害的重要因素。为了规范电动自行车头盔生产,我国修订发布了强制性国家标准《摩托车、电动自行车乘员头盔》(GB 811—2022),并于2023年7月开始实施。本文通过问卷调研探究电动自行车骑乘者佩戴头盔的行为及其主要影响因素,从强制性国标实施视角,提出了改善电动自行车骑乘者头盔佩戴行为的相关建议。

无信控交叉口电动自行车与机动车的冲突博弈研究

电动自行车骑行人与机动车驾驶人是城市道路交通系统的重要参与主体,在无信控交叉口电动自行车和右转机动车可能产生冲突。尤其当交通参与者不严格遵守通行优先权时,极大增加了参与主体交互的复杂性。本文以各交通主体的损失最小为目标,构建直行电动自行车与右转机动车的冲突博弈模型。在考虑两车驾驶人主观心理感知的前提下,引入前景理论价值函数和决策权重函数;根据演化博弈的复制动态方程分析博弈主体行为策略演化过程,得出不同条件下系统的最终稳定策略;利用数值仿真分析不同参数对系统演化的影响。研究结果表明,前景理论相关参数影响系统演化的收敛速度,不影响演化的最终结果;不同风格的电动自行车骑行人制定通行和让行决策时,表现出的风险偏好不同;互让损失的增加对电动自行车和机动车的通行概率起促进上升和抑制下降的作用,而机会损失的作用恰好相反。本文建立的理论模型可用于揭示道路主体在冲突行为中的决策演化规律,为我国城市交通管理控制提供理论依据。

电动自行车交通事故与建成环境的空间效应

针对电动自行车交通事故分析中缺少对建成环境因素影响的考虑,对电动自行车交通事故与建成环境的空间交互影响进行研究。将某市划分为2 114个交通小区,采集该市2 640起电动自行车交通事故数据,选取人口统计学特征、道路属性、兴趣点(point of interest,POI)等10个建成环境解释变量进行分析。基于空间计量经济学理论构建空间滞后模型、空间误差模型和空间杜宾模型,通过比选确定最优模型来研究电动自行车事故与建成环境的交互关系。结果表明:空间杜宾模型在拟合度和解释力上优于其他模型;该模型揭示了电动自行车事故与建成环境因素之间的直接效应、间接效应及总体效应,明确了事故发生的空间规律,为电动自行车事故高发区域的识别及预防提供了科学依据。

城市商业综合体非机动车交通空间优化

国家“双碳”目标要求加强以生活圈为单元的短距离低碳出行引导。城市商业综合体是5~15 min城市生活圈短距离出行的热点区域,文章意在为优化受到电动自行车、电动摩托车(简称电动车)保有量快速增长冲击的综合体非机动车交通空间组织提供系统性方案。通过现场观测记录和访谈,分析居民电动车、自行车出行目的和需求,揭示其出行的时空特征,剖析非机动车交通空间组织中存在的困境和挑战,提出运用统筹协作理念,探索规模配置—规划布局—组织管理等的非机动车交通组织系统优化策略。文章将有效解决长期被忽视的非机动车交通空间组织痛点和难点,为城市其他类型公共空间非机动车交通空间组织提供借鉴。

三元锂电池电动自行车火灾燃烧特性研究

通过对三元锂电池电动自行车开展实体燃烧试验,研究了电动自行车火灾的发展和蔓延过程,分析了燃烧现象、温度及烟气变化等典型特征。试验结果表明,电动自行车火灾发展迅速,燃烧过程中伴随射流火和爆炸现象。在距地面1 m处,测得的火羽流温度最高可达730℃,此时对应的最大热释放速率为1 290 kW。通过对烟气毒性进行评估,计算得到有效剂量百分数FED值为1.8,表明在此火灾环境中大约一半人员会因烟气毒气危害而丧生。此外,产生的烟气中还包含大量易燃易爆气体,其中H2含量最高为2 300μL/L。

电动自行车国内国际标准分析

电动自行车是基于自行车延伸出来的一种以车载蓄电池作为辅助能源,具有脚踏骑行能力,能实现电助动或/和电驱动功能的两轮自行车。具有节能、零排放、轻便灵活、价格便宜等特点。近年来电动自行车快速发展,成为人们短途出行重要交通工具。本文介绍电动自行车在国内和国际采用标准的差异,为检测机构测试和生产企业出口提供参考。

电动自行车运行循环工况的建立

本文介绍了建立电动自行车运行循环工况的作用和意义,分析了当前国内外相关测试方法现状,指出建立专用测试方法的必要性。通过对我国8个典型地区的电动自行车路况情况进行采集,获得大量反映中国电动自行车实际道路行驶特征的数据,据此形成了典型地区乃至全国的运行循环特征,并应用该结果开展了不同方法的续行里程比对,从而验证了相关参数的适宜性和方法的可行性。

基于结构方程的校园电动自行车危险骑行行为分析

为提高校园交通安全性,探究校园环境下大学生电动自行车危险骑行行为的影响因素。根据预调研结果,在计划行为理论(TPB)模型的基础上新增“环境管制态度”变量,编制调查问卷,构建基于拓展计划行为理论的结构方程模型(SEM);通过相关性分析和模型路径检验,对264份有效样本数据开展实证研究。结果表明:校园环境中,学生的日均骑行时长、骑行事故率、充电冲突率与危险骑行行为存在正相关性;行为态度、主观规范、知觉行为控制对安全行为意向有一定影响;对危险骑行行为的抑制作用最强的是安全行为意向,其次是环境管制态度,知觉行为控制对危险骑行行为呈现了与以往研究不同的促进作用。研究结果可为校园危险骑行行为的有效管控提供参考。

电动自行车混行下的城市非机动车道宽度设计

为支撑绿色出行背景下城市道路高品质骑行空间建设,提出了有电动自行车混行的非机动车道宽度精细化设计方法。通过观测上海市典型路段非机动车道的电动自行车(电动车)及传统自行车(自行车)运行规律,拟合非机动车流量、车均占有空间(per bike occupation space, BOS)和速度的关系,对比分析不同车道宽度及电动车比例下的非机动车道运行状态差异。依据BOS划分3类电动车比例下(<0.5、0.5~<0.7、≥0.7)非机动车道A~F共6级服务水平,并以B、C、D级服务水平为设计目标,给出3类电动车比例下非机动车道的最大、建议和最小设计宽度。分析结果显示,当电动车比例≥0.5时,最大设计宽度增加明显,且相同流量下3类电动车比例的建议设计宽度几乎相差0.5 m;当电动车比例≥0.7时,最小设计宽度增加明显。与现有规范标准相比,针对不同电动车比例给出的非机动车道宽度精细化设计结果均能满足2 000辆/h以上大流量的通行需求,并能适应不同的道路空间资源情形(富足、适中、紧张)。最后,通过实测数据及VISSIM仿真对设计效果进行验证,表明考虑电动车混行的非机动车道宽度精细化设计成果具有可行性。