Real-time Estimation of Clutch Slipping Torque in Hybrid Electric Vehicles during Slipping Start Process

doi:10.3901/JME.2025.16.217

Abstract

Abstract: During the slipping start process of hybrid electric vehicles, the clutch is used to crank the engine. However, since the clutch slipping torque changes with environmental factors, such as temperature, speed difference and etc., large deviation may occur between the actual slipping torque and the nominal one. The control performance with the nominal clutch slipping torque is deteriorated. Therefore, a real-time torque estimation method based on the unknown input observer is proposed to estimate the clutch slipping torque during the slipping start process. Since the speed difference between the clutch disks will decrease sharply during the slipping start, the viscous friction of the wet clutch cannot be ignored. Therefore, a “Coulomb+Viscous” friction model is established, and the effectiveness is validated. The bench test is carried out to estimate the clutch slipping torque under different oil temperatures and different initial speed differences during the slipping start process. The online estimation results show that the proposed estimation method has good precision.

Key words: hybrid electric vehicle, engine slipping start, real-time torque estimation

CLC Number:

U469

PENG Cheng, CHEN Li. Real-time Estimation of Clutch Slipping Torque in Hybrid Electric Vehicles during Slipping Start Process[J]. Journal of Mechanical Engineering, 2025, 61(16): 217-226.

References

[1] TRAN D, VAFAEIPOUR M, BAGHDADI M, et al. Thorough state-of-the-art analysis of electric and hybrid vehicle powertrains: Topologies and integrated energy management strategies[J]. Renewable and Sustainable Energy Reviews, 2020, 119: 109596.
[2] 董昊轩,殷国栋,庄伟超,等. 基于迭代动态规划的网联电动汽车经济性巡航车速优化[J]. 机械工程学报, 2021, 57(6): 121-130. DONG Haoxuan, YIN Guodong, ZHUANG Weichao, et al. Economic cruising velocity optimization using iterative dynamic programming of connected electric vehicle[J]. Journal of Mechanical Engineering, 2021, 57(6): 121-130.
[3] 唐小林,陈佳信,刘腾,等. 基于深度强化学习的混合动力汽车智能跟车控制与能量管理策略研究[J]. 机械工程学报, 2021, 57(22): 237-246. TANG Xiaolin, CHEN Jiaxin, LIU Teng, et al. Research on deep reinforcement learning-based intelligent car-following control and energy management strategy for hybrid electric vehicles[J]. Journal of Mechanical Engineering, 2021, 57(22): 237-246.
[4] 唐小林,陈佳信,高博麟,等. 基于云控系统高精度地图驱动的深度强化学习型混合动力汽车集成控制[J]. 机械工程学报, 2022, 58(24): 163-177. TANG Xiaolin, CHEN Jiaxin, GAO Bolin, et al. Deep reinforcement learning-based integrated control of hybrid electric vehicles driven by high definition map in cloud control system[J]. Journal of Mechanical Engineering, 2022, 58(24): 163-177.
[5] WU J, RUAN J, ZHANG N, et al. An optimized real-time energy management strategy for the power-split hybrid electric vehicles[J]. IEEE Transactions on Control Systems Technology, 2019, 27(3): 1194-1202.
[6] XU X, LIANG Y, JORDAN M, et al. Optimized control of engine start assisted by the disconnect clutch in a P2 hybrid automatic transmission[J]. Mechanical Systems and Signal Processing, 2019, 124: 313-329.
[7] YU S, DONG G, LI L. Transient characteristics of emissions during engine start/stop operation employing a conventional gasoline engine for HEV application[J]. International Journal of Automotive Technology, 2008, 9(5): 543-549.
[8] 于亮,马彪,陈漫,等. 润滑油温度对铜基湿式离合器摩擦转矩的影响[J]. 机械工程学报, 2020, 56(20): 155-163. YU Liang, MA Biao, CHEN Man, et al. Influence of the temperature of lubricating oil on the friction torque of cu-based wet clutch[J]. Journal of Mechanical Engineering, 2020, 56(20): 155-163.
[9] KIM S, CHOI S. Cooperative control of drive motor and clutch for gear shift of hybrid electric vehicles with dual-clutch transmission[J]. IEEE/ASME Transactions on Mechatronics, 2020, 25(3): 1578-1588.
[10] GÖPPERT G. Adaptation of a wet clutch torque model in electrified drivelines[J]. Forschung im Ingenieurwesen, 2021, 85(4): 913-922.
[11] OH J, CHOI S. Real-time estimation of transmitted torque on each clutch for ground vehicles with dual clutch transmission[J]. IEEE/ASME Transactions on Mechatronics, 2015, 20(1): 24-36.
[12] KIM S, OH J, CHOI S. Driveline torque estimations for a ground vehicle with dual-clutch transmission[J]. IEEE Transactions on Vehicular Technology, 2018, 67(3): 1977-1989.
[13] XU D, ZHANG J, ZHOU B, et al. Robust hierarchical estimator of clutch torques for a compound power-split hybrid electric vehicle[J]. Mechanical Systems and Signal Processing, 2019, 134: 106320.
[14] 赵治国,顾佳鼎,何露. 干式双离合器自动变速器换档过程离合器传递转矩估计[J]. 机械工程学报, 2017, 53(14): 77-87. ZHAO Zhiguo, GU Jiading, HE Lu. Estimation of torques transited by twin-clutch during shifting process for dry dual clutch transmission[J]. Journal of Mechanical Engineering, 2017, 53(14): 77-87.
[15] CHOWDHARY G , MÜHLEGG M , JOHNSON E. Exponential parameter and tracking error convergence guarantees for adaptive controllers without persistency of excitation[J]. International Journal of Control, 2014, 87(8): 1583-1603.