Design 2-Speed Transmission for Compact Electric Vehicle Using Dual Brake System

Han, Jae-Oh; Shin, Jeongho; Kim, Jae‐Chang; Oh, Seong-Hwan

doi:10.3390/app9091793

Cited by 9 publications

(9 citation statements)

References 9 publications

(12 reference statements)

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“…The power balance of the vehicle is represented by (3), and (4) represents the feasible design space, where the design, state and control variables are bounded. Equation ( 4) also represents the component limits.…”

Section: Problem Definitionmentioning

confidence: 99%

“…Admittedly, the emerging EV market is mainly dominated by single-speed transmissions (SSTs). Nevertheless, to optimize key performance indicators (KPIs), for example, energy consumption, system cost and performance, research on multi-speed transmissions is gaining popularity, such as twospeed transmissions and continuously variable transmissions (CVTs) [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

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Co-Design of CVT-Based Electric Vehicles

2021

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For an electric vehicle (EV) with a continuously variable transmission (CVT), a novel convex programming (CP)-based co-design method is proposed to minimize the total-cost-of-ownership (TCO). The integration of the electric machine (EM) and the CVT is the primary focus. The optimized system with co-design reduces the TCO by around 5.9% compared to a non-optimized CVT-based EV (based on off-the-shelf components) and by around 2% compared to the EV equipped with a single-speed transmission (SST). By taking advantage of the control and design freedom provided by the CVT, the optimal CVT, EM and battery sizes are found to reduce the system cost. It simultaneously finds the optimal CVT speed ratio and air-flow rate of the cooling system reducing the energy consumption. The strength of co-design is highlighted by comparing to a sequential design, and insights into the design of a low-power EV that is energy-efficient and cost-effective for urban driving are provided. A highly integrated EM-CVT system, which is efficient, low-cost and lightweight, can be expected for future EV applications.

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Section: Problem Definitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Co-Design of CVT-Based Electric Vehicles

2021

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“…When the vehicle speed is low, the electromotive force generated by the motor is small, it is difficult to charge the battery, and it will reduce the reliability of braking when participating in regenerative braking. Therefore, regenerative braking doesn't work at low vehicle speeds [25,26]. When the braking intensity is too strong, regenerative braking also needs to stop working.…”

Section: Security and Compliance Constraintsmentioning

confidence: 99%

Performance Analysis of Electronic Mechanical Assisted Braking of Environmental-Friendly Vehicles Based on Pedal Decoupling

2021

IJOMAM

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This research aims to reduce the impact of the regenerative braking force generated by the new energy vehicle on the braking performance during regenerative braking. It mainly focuses on the braking design scheme of pedal decoupling and the corresponding pedal decoupling strategy. First, the pedal decoupling scheme is designed, and the electronic mechanical assisted braking model and the overall model of the driving vehicle are established. The model includes electromechanical booster model, active accumulator model, and hydraulic braking model. The electromechanical booster model mainly includes the permanent magnet synchronous motor model and the transmission mechanism model. Then, the pedal decoupling strategy based on the new decoupling scheme is studied, and the decoupling process is divided into three stages. According to the control requirements of each stage, the control of pressure reducing valve and the pump motor in the electronic stability program (ESP) is realized, so as to adjust the brake circuit hydraulic pressure during the decoupling process. Moreover, the decoupling current is calculated to adjust the torque of the electromechanical booster motor, so as to adjust the pedal feel. Finally, the control strategy of the electro-mechanical assist motor is designed to realize the control of the motor. The experimental results show that the designed decoupling strategy can make the master cylinder hydraulic pressure change according to the distribution result of the braking force distribution strategy under the three braking strengths of low, medium, and high, which has a good decoupling effect. In addition, the decoupling electro-hydraulic compound braking realizes the precise control of the wheel cylinder pressure and effectively recovers the braking energy. The braking energy feedback efficiency reaches 54.8%. The designed decoupling strategy provides some references for the adoption of pedal decoupling in automobile assisted braking.

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“…Several recent studies [6][7][8] have investigated the application of multi-speed transmissions to electric vehicle platforms [9]. These are viewed as one of the most promising options that meet the needs for both a wider range of torque applications and higher energy efficiencies than single speed equivalents [10,11].…”

Section: Introductionmentioning

confidence: 99%

The Structure and Optimal Gear Tooth Profile Design of Two-Speed Transmission for Electric Vehicles

et al. 2021

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As environmental regulations have been strengthened worldwide since the Paris Climate Agreement, the automobile industry is shifting its production paradigm to focus on eco-friendly vehicles such as electric vehicles and hydrogen-battery vehicles. Governments are banning fossil fuel vehicles by law and expanding the introduction of green vehicles. The energy efficiency of electric vehicles that use a limited power source called batteries depends on the driving environment. Applying a two-speed transmission to an electric vehicle can optimize average speed and performance efficiency at low speeds, and achieve maximum speed with minimal torque at high speeds. In this study, a two-speed transmission for an electric vehicle has been developed, to be used in a compact electric vehicle. This utilizes a planetary gear of a total of three pairs, made of a single module which was intended to enable two-speed. The ring gear was removed, and the carrier was used in common. When shifting, the energy used for the speed change is small, due to the use of the simple method of fixing the sun gear of each stage. Each gear was designed by calculating bending strength and surface durability, using JGMA standards, to secure stability. The safety factor of the gears used in the transmission is as follows: all gears have been verified for safety with a bending strength of 1.2 or higher and a surface pressure strength of 1.1 or higher. The design validity of the transmission was verified by calculating the gear meshing ratio and the reference efficiency of the gear. The transmission to be developed through the research results of this paper has a simple and compact structure optimized for electric vehicles, and has reduced shift shock. In addition, energy can be used more efficiently, which will help improve fuel economy and increase drive range.

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Design 2-Speed Transmission for Compact Electric Vehicle Using Dual Brake System

Cited by 9 publications

References 9 publications

Co-Design of CVT-Based Electric Vehicles

Co-Design of CVT-Based Electric Vehicles

Performance Analysis of Electronic Mechanical Assisted Braking of Environmental-Friendly Vehicles Based on Pedal Decoupling

The Structure and Optimal Gear Tooth Profile Design of Two-Speed Transmission for Electric Vehicles

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