RECUPERATION SYSTEM OF ELECTRIC BUSES

ABSTRACT

The adoption of electric buses in urban transportation systems is a critical step toward sustainable and energy-efficient mobility. One of the key features that enhance the efficiency of electric buses is energy recuperation. This paper aims to analyze the impact of driver behavior on the efficiency of regenerative braking systems in electric buses. Field experiments were conducted in Tashkent with two Yutong ZK 6126 BEVG electric buses equipped with a 350 kWh battery. Results indicate that careful and smooth driving leads to up to 10% higher battery charge retention after a full day of operation. This study highlights the importance of driver training and driving style in maximizing the benefits of recuperation systems.

АННОТАЦИЯ

Внедрение электробусов в городские транспортные системы является важным шагом на пути к устойчивой и энергоэффективной мобильности. Существенной характеристикой, повышающей эффективность электробусов, является рекуперация энергии, которая преимущественно осуществляется посредством рекуперативного торможения. Данная статья направлена на анализ влияния поведения водителя на эффективность работы систем рекуперативного торможения в электробусах. В Ташкенте были проведены полевые испытания с участием двух электробусов модели Yutong ZK 6126 BEVG с аккумуляторной батареей ёмкостью 350 кВт⋅ч. Результаты показали, что аккуратный и плавный стиль вождения способствует сохранению заряда батареи до 10% больше после полного рабочего дня. Исследование подчеркивает важность подготовки водителей и соблюдения правильного стиля вождения для максимизации эффективности систем рекуперации энергии.

Keywords: recuperation system, electric buses, regenerative braking, energy efficiency, driver behavior

Ключевые слова: система рекуперации, электробусы, рекуперативное торможение, энергоэффективность, поведение водителя.

INTRODUCTION. The rapid urbanization and increasing environmental concerns have accelerated the transition to electric buses in public transportation. Electric buses reduce greenhouse gas emissions and dependence on fossil fuels. Energy recuperation, primarily facilitated by regenerative braking, is a crucial technology that significantly enhances the efficiency of electric buses. This system converts kinetic energy into electrical energy during braking and stores it in the battery for reuse. Despite its potential, the efficiency of recuperation systems can vary based on several factors, including driving behavior. This paper investigates the impact of driver behavior on energy recuperation efficiency in electric buses.

METHODOLOGY. Field research was conducted at the 8th Motor Depot in Tashkent. Two Yutong ZK 6126 BEVG electric buses, each equipped with a 350 kWh battery, were selected for the study. Both buses operated on the same urban route covering 280 km per day. The first bus was driven by an experienced driver employing smooth braking techniques, while the second bus was driven by a less experienced driver who frequently used abrupt braking. At the conclusion of each operational day, the battery charge levels were meticulously recorded to evaluate the impact of driving styles on the efficiency of energy recuperation.

Figure 1. Decoupled braking energy recovery system for electric bus

RESULTS. The first bus, driven by the experienced driver, returned to the depot with 30% battery charge remaining, while the second bus, driven by the less experienced driver, returned with only 20% battery charge. This significant 10% difference underscores the crucial role that driving style plays in optimizing the performance of energy recuperation systems. Additionally, data collected during the experiment showed that the experienced driver applied brakes smoothly and gradually, resulting in more frequent activation of the regenerative braking system. In contrast, the less experienced driver often used abrupt braking, leading to a higher reliance on mechanical brakes and reduced recuperation efficiency.

Energy consumption measurements revealed that the first bus consumed approximately 1.1 kWh per kilometer, whereas the second bus averaged 1.3 kWh per kilometer over the same distance. This discrepancy further confirms that smooth driving enhances energy efficiency and reduces battery depletion rates.

Table 1.

Energy Consumption and Recuperation Efficiency Comparison

Furthermore, telemetry data from the buses indicated that the experienced driver managed to recuperate up to 28% of the kinetic energy during braking events, while the second bus achieved only 19% energy recovery. These figures emphasize the tangible impact of driving behavior on recuperation efficiency and overall energy consumption.

DISCUSSION. The findings align with existing research indicating that regenerative braking systems perform optimally under smooth driving conditions with gradual acceleration and deceleration. Frequent and abrupt braking not only reduces energy recuperation efficiency but may also contribute to faster battery degradation and increased maintenance costs. Cities such as Shenzhen and Zhengzhou have reported significant efficiency improvements through the adoption of electric buses equipped with advanced recuperation systems and the implementation of driver training programs. Integrating real-time recuperation monitoring and driver assistance systems can further enhance energy efficiency in urban transport networks.

CONCLUSION. Efficient use of recuperation systems in electric buses is crucial for maximizing energy savings and extending battery life. This study demonstrated that driving behavior significantly affects the performance of regenerative braking systems. Results from field experiments in Tashkent indicated that careful and smooth driving can lead to up to 10% higher battery charge retention and reduced energy consumption by approximately 15% compared to aggressive driving styles. Driver behavior plays a pivotal role in this process. Training programs focusing on smooth driving techniques can significantly improve recuperation efficiency and overall operational performance. Moreover, real-time recuperation monitoring systems and driver feedback technologies could help drivers maintain optimal driving patterns. Future research should explore the integration of AI-based driver assistance systems to optimize energy recuperation further. Additionally, larger-scale studies involving diverse driving conditions and fleet types will be valuable for developing comprehensive recommendations on maximizing the efficiency of recuperation systems in electric buses.

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