Article

• MULTI-OBJECTIVE ENERGY MANAGEMENT BASED ON HYBRID UKF, MACHINE LEARNING, AND NSGA-II FOR LITHIUM-ION BATTERIES IN SOLAR ENERGY STORAGE SYSTEMS

  Khiết Phạm, Tùng Phạm, Thiện Huỳnh (Author)

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  This paper proposes a hybrid energy management method for lithium-ion batteries in solar energy storage systems to improve operational efficiency and extend battery lifetime. The proposed method integrates three components: the Unscented Kalman Filter (UKF) for State of Charge (SOC) estimation, a Long Short-Term Memory (LSTM) model for State of Health (SOH) and Remaining Useful Life (RUL) prediction, and the NSGA-II multi-objective optimization algorithm for determining optimal charging-discharging schedules. A first-order RC equivalent circuit model is adopted to represent the dynamic behavior of lithium-ion batteries under variable operating conditions. Current, voltage, temperature, and UKF-estimated SOC are used as input features for the LSTM model to capture battery degradation trends. Based on these health indicators, a multi-objective optimization problem is formulated to minimize electricity exchange cost, depth of discharge (DOD), and battery degradation index. MATLAB/Simulink simulation results show that the proposed method reduces operating cost by approximately 27%, DOD by 22%, and battery degradation by 18% compared with rule-based control. These results indicate the potential applicability of the proposed UKF-LSTM-NSGA-II approach for intelligent energy management in renewable energy storage systems.

• COMPARISON OF COMBUSTION AND EMISSION CHARACTERISTICS OF SEVERAL COMBUSTION CHAMBER GEOMETRIES IN A DIESEL ENGINE

  Quốc Anh Đào, Van Van Luong, Van Thanh Ngo (Author)

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  This study employed DIESEL-RK simulation software to investigate the effects of three combustion chamber geometries (Baseline Bowl, Re-entrant Bowl, and Omega Bowl) on the combustion and emission characteristics of an AVL 5402 diesel engine. The results showed that the Omega Bowl provided the best overall performance, increasing engine power by 6.7%, reducing brake specific fuel consumption (BSFC) by 2.6%, and lowering NOₓ emissions by 11.8% compared with the baseline configuration. However, PM emissions increased by 12.1% due to stronger spray interaction. To address this limitation, the operating parameters of the Omega Bowl were optimized. The optimal condition, consisting of SOI = 10° BTDC, SR = 1.2, and P_in = 1,25 bar, reduced NOₓ and PM emissions by 28.7% and 12.6%, respectively, while slightly improving engine power and fuel economy. The results demonstrate that the combined optimization of combustion chamber geometry and operating parameters is an effective approach for improving diesel engine performance and reducing emissions.

• ANALYSIS OF BRAKING DYNAMICS AND THERMAL CHARACTERISTICS IN PASSENGER CARS BASED ON A BIDIRECTIONAL INTERACTION MODEL

  Phi Võ Huỳnh, Vân Nguyễn Thái, Dương Vũ (Author)

  Abstract | PDF (Vietnamese) | Views: 25 Downloads: 13

  This paper investigates the bidirectional interaction between brake actuation parameters and vehicle dynamics, alongside thermal analysis of disc brake assemblies based on a simplified equivalent thermal model. A generalized Matlab-based algorithm is developed to simulate the variation of braking dynamic state parameters under optimal braking (forward approach) and evaluate Mean Fully Developed Deceleration (MFDD) in accordance with UN R13-H regulations (inverse approach). Simulation results across various load cases demonstrate consistent alignment between brake actuation parameters and braking dynamics, while confirming that MFDD values satisfy international standards. Furthermore, a simplified thermal model in Ansys Workbench verifies that the temperatures generated at the friction interfaces remain within the stable friction zone of the brake components.