http://yetl.yabesh.ir/yetl1/handle/yetl/4303705 2026-08-27T07:59:58Z http://yetl.yabesh.ir/yetl1/handle/yetl/4315550 Integrating Laminar Burning Velocity Into an Empirical Kinetic Model for Predicting the Ignition Delay of Biodiesel Blends Nguyen, Vu Hoang; Duong, Minh Quang Abstract. Accurate prediction of ignition delay time is fundamental for optimizing combustion phasing in compression ignition engines. Classical empirical models often fail to capture the complex auto-ignition behavior of oxygenated fuels like biodiesel due to the omission of flame propagation characteristics. This study proposes an empirical kinetic model that integrates the maximum laminar burning velocity and cetane number to represent the synergy between physical transport and chemical kinetics. The model was developed using a robust experimental dataset derived from a Cooperative Fuel Research engine and a constant-volume bomb. Five primary parameters—cetane number, maximum laminar burning velocity, in-cylinder pressure at the start of injection, in-cylinder temperature at the start of injection, and equivalence ratio—were incorporated into a power-law formulation. To ensure predictive capability and avoid numerical overfitting, the 330 experimental data points were randomly divided into an 80% training set (264 points) for model calibration and a 20% independent testing set (66 points) for validation. The evaluation demonstrates stable accuracy across both datasets, with the independent testing phase achieving a mean absolute percentage error between 4.23% and 7.34% and a coefficient of determination reaching 0.922 for specific biodiesel blends. The integration of maximum laminar burning velocity enhances the model's sensitivity to the thermodynamic state, providing a reliable kinetic-based tool for advanced combustion simulations of sustainable fuels. 2026-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4315549 Load Range Extension in Gasoline/Diesel Dual-Fuel Engines: A Mixture Concentration and Reactivity Control Approach Zhang, Shanshan; Hu, Tiantian; Wu, Binyang; Guo, Wenyue; Su, Wanhua Abstract. In gasoline/diesel dual-fuel engines, regulating fuel concentration and reactivity stratification effectively extends the high-load limit. This study investigates the effects of mixing characteristics of low- and high-reactivity fuels on combustion and emission performance. Based on intake airflow characteristics, an asymmetric port fuel injection strategy is proposed to control gasoline concentration stratification. Results show that forming local fuel-rich zones (equivalence ratio > 0.6) in the near-wall area significantly reduces total hydrocarbons and carbon monoxide emissions. Experimental and numerical analyses reveal that advancing diesel injection timing enhances chemical reactivity in the boundary zones while suppressing high-temperature oxidation in the core zones. Specifically, advancing the injection timing from 20 to 40 crank angle degrees before top dead center improves brake thermal efficiency by 1.5% and reduces total hydrocarbons, carbon monoxide, and nitrogen oxides emissions by 22.90%, 15.91%, and 40.60%, respectively. Late diesel injection offers greater flexibility in combustion phasing control. With the diesel double-injection strategy, a 90% gasoline substitution ratio achieves 43.57% brake thermal efficiency at 1.0-MPa brake mean effective pressure. At 1.5-MPa brake mean effective pressure, a 75% gasoline substitution ratio achieves 44.13% brake thermal efficiency, with emissions of 1.58, 5.76, and 1.88 g/kWh of total hydrocarbons, carbon monoxide, and nitrogen oxides, respectively. 2026-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4315548 Thermal Efficiency and Emissions of a Commercial Vehicle Hybrid-Dedicated Diesel Engine With Miller/Atkinson Cycle and High Compression Ratio: An Experimental Study Wang, Rui; Wang, Xiaosa; Lin, Zhiqiang; Wang, Hu; Wang, Xiaohui; Lu, Yao Abstract. To address energy security and global environmental challenges, this study conducted bench tests to enhance the thermal efficiency of commercial vehicle hybrid-dedicated diesel engines, developing powertrain systems with high fuel economy and competitive total cost of ownership. Focusing on key conditions for thermal efficiency optimization, this study employed the Miller/Atkinson cycle and high compression ratio configurations. Through experimental and thermodynamic analyses, the study investigated how effective compression ratio (ECR) influences combustion processes and emission characteristics, proposing a technical route to improve thermal efficiency under limited peak cylinder pressure. Experimental results demonstrated that ECR modifications effectively regulate the in-cylinder thermal environment, with reduced temperature and pressure providing margin for advancing the start of injection, thereby minimizing combustion losses. Without a significant increase in nitrogen oxide emissions relative to the baseline, the late intake valve closing strategy, combined with a high geometric compression ratio, significantly reduced soot emissions at low load. Compared to the baseline, large soot particles are reduced by over 85%. The increased expansion ratio improved thermal-work conversion efficiency while reducing pumping losses, resulting in an approximately 1.2% increase in the maximum theoretical thermal efficiency. The maximum brake thermal efficiency of the optimized diesel engine increased by 2.5%, and the minimum brake specific fuel consumption (BSFC) dropped from 192.6 g/(kW · h) to 187.5 g/(kW · h). Furthermore, the BSFC under low-load conditions was significantly reduced by over 10 g/(kW · h). 2026-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4315547 The Automotive Sector: Reuse, Renewal, Disposal and Environmental Impact of Automotive Batteries—An Overview Capata, Roberto; Calabria, Alfonso; Martellucci, Leone Abstract. Batteries are a key element of electric vehicles, influencing their range and cost. Lithium-ion batteries dominate the market, with a reliability that exceeds 1000 charging cycles. Battery Electric Vehicles (BEV) use 400 V or 800 V batteries, the latter being more cost-effective for production. After about 10 years, exhausted batteries can be reused (if they retain 70–80% capacity) for energy storage from renewable sources or recycled. Recycling, especially through metallurgical processes, makes it possible to recover all materials, including lithium. This study analyzes reuse and recycling, highlighting critical issues and possible optimizations. Batteries represent “virtual mines” of strategic materials. Re-celling (repair of battery packs) is also explored. Reuse reduces environmental impact, but large-scale dismantling needs to be standardized, favored by market growth and continuous research. 2026-01-01T00:00:00Z