Design and analysis of an engine-start control strategy for a single-shaft parallel hybrid electric vehicle

• Published in: Energy (Oxford) Vol. 202; p. 117621
• Main Authors: Zhao, Chen, Zu, Bingfeng, Xu, Yuliang, Wang, Zhen, Zhou, Jianwei, Liu, Lina
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2020; Elsevier BV
• Subjects: Algorithms; Circuits; Clutches; Computer simulation; Design; Design parameters; Dynamic characteristics; Electric vehicles; energy use and consumption; Engine-start control strategy; Equivalent fuel consumption; Feedback control; Feedforward control; Feedforward-feedback control; Fuel economy; fuels; Hybrid electric vehicles; hydraulic systems; model validation; Powertrain; Proportional integral; Separating clutch; simulation models; Single-shaft parallel hybrid electric vehicle; Strategy; systems engineering; Equivalent fuel consumption; Separating clutch; Single-shaft parallel hybrid electric vehicle; Feedforward-feedback control; Engine-start control strategy
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2020.117621

The key point of a single-shaft parallel hybrid electric vehicle is the ability to start the engine while propelling the vehicle by utilizing a single traction motor. To pursue better driving comfort, an accurate engine-start process should be designed. For the purpose of smoothly starting the engine, this paper proposes a seven-phase engine-start control strategy with the assistance of the slipping status of the separating clutch and shifting clutch. A detailed drivetrain model of a single-shaft parallel hybrid electric vehicle is established to support the designed control strategy with consideration of the dynamic characteristics of the engine, motor and clutch. With the support of the hydraulic circuit established in this paper, feedforward-feedback controller based on proportional-integral (PI) algorithm is developed to track the demanded pressure for separating clutch. Simulation and test results validate that the proposed engine-start control strategy is feasible and effective for improving driving comfort and ensuring the drivability of the target vehicle. The key design parameters of the control strategy are optimized for the minimal equivalent fuel consumption. Test results indicate that the designed control strategy can effectively improve the fuel economy of engine-start control process compared with conventional strategy. •A detailed model of single-shaft parallel HEV considering dynamic characteristics.•A multi-phase engine-start control strategy improves driving comfort.•Key design parameters of the engine-start control strategy are optimized.•Fuel consumption is decreased in designed engine-start process.