Updated on 2025/05/08

写真a

 
FANG, Yiyuan
 
Affiliation
Faculty of Science and Engineering, Graduate School of Environment and Energy Engineering
Job title
Assistant Professor(without tenure)

Research Interests

  • 電動車両の電費予測

  • エコドライブ

  • 電気自動車

 

Papers

  • A Passive Experiment on Route Bus Speed Change Patterns to Clarify Electrification Benefits

    Yiyuan Fang, Wei-Hsiang Yang, Yushi Kamiya

    World Electric Vehicle Journal   16 ( 3 ) 178 - 178  2025.03  [Refereed]

    Authorship:Lead author

     View Summary

    In addition to the widely recognized benefits of reducing carbon emissions and protecting the environment, the authors believe that bus electrification has potential advantages in enhancing driving safety, improving passenger comfort, and reducing driver fatigue—areas that have not yet been sufficiently studied and emphasized. Safety and comfort are fundamental objectives in the continuous development of transportation systems. They are directly and closely related to both passengers and drivers and are among the top priorities when individuals choose their mode of transportation. Therefore, these aspects deserve broader and more in-depth attention and research. This study aims to identify the potential advantages of route bus electrification in terms of safety and comfort. The results of a passive experiment on the speed profile of buses operating on actual routes are presented here. Firstly, we focus on the acceleration/deceleration at the starting/stopping stops, specifically for regular-route buses, and obtain the following information: I. Starting acceleration from a bus stop is particularly strong in the second half of the acceleration process, being suitable for motor-driven vehicles. II. The features of the stopping deceleration at a bus stop are “high intensity” and “low dispersion”, with the latter enabling the refinement of regenerative settings and significantly lowering electricity economy during electrification. And we compare the speed profile of an electric bus with those of a diesel bus and obtain the following information: III. Motor-driven vehicles offer the advantages of “high acceleration performance” and “no gear shifting”, making them particularly suitable for the high-intensity acceleration required when route buses depart from stations. This not only simplifies driving operations but also enhances lane-changing safety. And by calculating and analyzing the jerk amount, we could quantitatively demonstrate the comfortable driving experience while riding on this type of bus where there is no shock due to gear shifting. IV. While the “high acceleration performance” of motor-driven vehicles produces “individual differences in the speed change patterns”, this does not translate to “individual differences in electricity consumption”, owing to the characteristics of this type of vehicle. With engine-driven vehicles, measures such as “slow acceleration” and “shift up early” are strongly encouraged to realize eco-driving, and any driving style that deviates from these measures is avoided. However, with motor-driven vehicles, the driver does not need to be too concerned about the speed change patterns during acceleration. This characteristic also suggests a benefit in terms of the electrification of buses.

    DOI

  • Developing a Simple Electricity Consumption Prediction Formula for the Pre-Introduction Prediction for Electric Buses

    Yiyuan Fang, Wei-hsiang Yang, Yuto Ihara, Yushi Kamiya

    World Electric Vehicle Journal   16 ( 2 ) 67 - 67  2025.01  [Refereed]  [Invited]

    Authorship:Lead author

     View Summary

    This study aims to develop a theoretical formula to help bus operators easily predict electricity consumption while introducing a certain type of electric bus on a predetermined route. The formula requires vehicle-side information (such as air resistance coefficient, rolling resistance coefficient, vehicle weight, powertrain efficiency, kinetic energy recovery rate, auxiliary equipment electricity consumption, and other vehicle-related data) for construction and road-/operation-side information (such as average driving speed, number of starts and stops, road gradients, and other road-/operation-related data) for prediction. First, herein, as a basic study to construct the theoretical formula, a developed electric bus and its vehicle electricity consumption simulator are employed. We then perform a comparative analysis considering the comparison of loss between the actual operation on public roads and the assumed constant velocity when running on flat roads. Next, we develop theoretical equations for the generalization of velocity and gradient changes and simplified modeling of electricity consumption prediction. Considering the burden of information collection on operators, we categorize it into three stages. In this paper, we first organize the minimum necessary road-/operation-side information (route/operational indicators). Next, we propose a theoretical formula for electricity consumption prediction constructed based on vehicle-side information. Finally, we validate the validity and accuracy of the constructed formula using electric buses and their on-road operational data that we developed earlier. The verification results showed that, after obtaining vehicle-side and road-/operation-side information, the theoretical formula constructed in this study achieved an electricity consumption prediction with an average error of 6% (high-accuracy method). This result demonstrates the practicality of using the theoretical formula to predict the electricity consumption/range of electric buses operating on specific routes.

    DOI

  • Speed Change Pattern Optimization for Improving the Electricity Consumption of an Electric Bus and Its Verification Using an Actual Vehicle

    Yiyuan Fang, Wei-hsiang Yang, Yushi Kamiya, Takehito Imai, Shigeru Ueki, Masayuki Kobayashi

    World Electric Vehicle Journal   15 ( 1 ) 16 - 16  2024.01  [Refereed]  [Invited]

    Authorship:Lead author

     View Summary

    In this study, we focused on the eco-driving of electric vehicles (EVs). The target vehicle is an electric bus developed by our research team. Using the parameters of the bus and speed pattern optimization algorithm, we derived the EV’s eco-driving speed pattern. Compared to the eco-driving of internal combustion engine vehicles (ICVs), we found several different characteristics. We verified these characteristics with actual vehicle driving test data of the target bus, and the results confirmed its rationality. The EV’s eco-driving method can improve electricity consumption by about 10–20% under the same average speed.

    DOI

 

Syllabus

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Internal Special Research Projects

  • 電動車両の特性を考慮した省エネ最適化計算と実車による検証

    2024  

     View Summary

    自動車の省エネ方法は、ますます重要となっている。その方法の一つとして、エコドライブは過去 20 年間にわたって大きな研究関心を集めてきた。多くの研究で、エコドライブは低コストで有効的な温室ガス排出削減・省エネ方法であることが示されている。しかし、従来の内燃機関車と大きく異なる電気自動車の普及と伴い、電気自動車に対するエコドライブ研究は課題となっている。本提案は「電動車両の特性を基に省エネ速度変化最適化と実車走行検証による電費改善」を目指すものである。開発した電動車両の高精度電費シミュレータと速度変化パターン最適化アルゴリズムを使用し、電動車両用のエコドライブ速度パターン(省エネ運転/制御方法)を導出する(課題①)。また、これまで自動車省エネ運転の研究では、最適化手法によって導き出された結果を実際の実車走行実験によって詳細に検証し、工学原理を解析する先例は非常に少ない。申請者はこの工学検証が非常に重要であると考えており、本研究では電気自動車や燃料電池自動車等の各種電動車両を公道、シャシダイナモ等の道路環境で走行し、最適化結果の検証実験を行う(課題②)。計算と実験を緊密に結びつけることで、最適化結果の現実への適用効果をさらに確認し、提案省エネ運転方法の汎用性を高めることを目指す。研究成果を下記の論文誌に投稿した.[1] 方亦園,諸橋陽太,楊イ翔,紙屋雄史:電動大型車の電費改善のための速度変化パターン最適化計算ならびに実車シャシダイナモ試験による検証(第2報)-実測データに基づくバッテリ内部抵抗値と高電圧配線部抵抗値の導出ならびに同部位の損失の追加考慮-,自動車技術会論文集, Vol. 56, No. 1, 20254045, pp.122-127. 2025.