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Journal of Thermal Science 2024年第2期33卷 578-590页

作者： LI Xiaolin WANG Jun CAO Wenxiang ZHANG Xuesong school of automotive and Traffic engineering Jiangsu UniversityZhenjiang212013China

This study is to utilize the heat-absorbing and releasing capabilities of phase change materials(PCM)to regulate the surface temperature fluctuations of batteries during charging and discharging.The goal is to keep the battery within the optimal operating temperature range.The impact of PCM thickness and phase change temperature on battery temperature is investigated by encircling a cylindrical battery with a PCM ring.To improve the thermal conductivity of PCM,expanded graphite(EG) is added to make a composite phase change material(CPCM),and the effects of various EG mass ratios on battery surface temperature and CPCM utilization level are investigated.The findings indicate that increasing PCM thickness effectively extends temperature control time,but its impact is limited.The difference in phase change temperature of PCM controls the battery temperature in different temperature ranges.Lower phase change temperatures are unsuitable for controlling battery temperature in high temperature environments.The addition of EG enhances the thermal conductivity of PCM,leading to further control of battery temperature.The results show that the addition of 6%(mass ratio) EG to CPCM extends the effective temperature control time by 11 min and improves by 28% compared to a single PCM.The CPCM utilization is also more satisfactory and achieved a balance between heat storage and thermal conductivity in a battery thermal management system(BTMS) based on PCM.

关键词： phase change material expanded graphite thermal management system effective control time

LLTH‑YOLOv5:A Real‑Time Traffic Sign Detection Algorithm for Low‑Light Scenes

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automotive Innovation 2024年第1期7卷 121-137页

作者： Xiaoqiang Sun Kuankuan Liu Long Chen Yingfeng Cai Hai Wang automotive engineering Research Institute Jiangsu UniversityZhenjiang 212013China school of automotive and Traffic engineering Jiangsu UniversityZhenjiang 212013China

Traffic sign detection is a crucial task for autonomous driving systems.However,the performance of deep learning-based algorithms for traffic sign detection is highly affected by the illumination conditions of scenarios.While existing algo-rithms demonstrate high accuracy in well-lit environments,they suffer from low accuracy in low-light scenarios.This paper proposes an end-to-end framework,LLTH-YOLOv5,specifically tailored for traffic sign detection in low-light scenarios,which enhances the input images to improve the detection performance.The proposed framework comproses two stages:the low-light enhancement stage and the object detection stage.In the low-light enhancement stage,a lightweight low-light enhancement network is designed,which uses multiple non-reference loss functions for parameter learning,and enhances the image by pixel-level adjustment of the input image with high-order curves.In the object detection stage,BIFPN is introduced to replace the PANet of YOLOv5,while designing a transformer-based detection head to improve the accuracy of small target detection.Moreover,GhostDarkNet53 is utilized based on Ghost module to replace the backbone network of YOLOv5,thereby improving the real-time performance of the model.The experimental results show that the proposed method significantly improves the accuracy of traffic sign detection in low-light scenarios,while satisfying the real-time requirements of autonomous driving.

关键词： Deep learning Traffic sign detection Low-light enhancement YOLOv5 Object detection

Fatigue Life Prediction for SiC/Al Materials Based on Path Planning Algorithm Considering Residual Stress

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Chinese Journal of Mechanical engineering 2023年第1期36卷 344-355页

作者： Wenqian Shang Xintian Liu Xu Wang Xiaolan Wang school of Mechanical and automotive engineering Shanghai University of Engineering ScienceShanghai201620China

To explore the influence of path deflection on crack propagation,a path planning algorithm is presented to calculate the crack growth length.The fatigue crack growth life of metal matrix composites(MMCs)is estimated based on an improved Paris formula.Considering the different expansion coefficient of different materials,the unequal shrinkage will lead to residual stress when the composite is molded and cooled.The crack growth model is improved by the modified stress ratio based on residual stress.The Dijkstra algorithm is introduced to avoid the cracks passing through the strengthening base and the characteristics of crack steps.This model can be extended to predict crack growth length for other similarly-structured composite materials.The shortest path of crack growth is simulated by using path planning algorithm,and the fatigue life of composites is calculated based on the shortest path and improved model.And the residual stress caused by temperature change is considered to improve the fatigue crack growth model in the material.The improved model can well predict the fatigue life curve of composites.By analyzing the fatigue life of composites,it is found that there is a certain regularity based on metal materials,and the new fatigue prediction model can also reflect this regularity.

关键词： Fatigue life estimation Path planning Residual temperature stress Composite material

Energy-optimized adaptive cruise control strategy design at intersection for electric vehicles based on speed planning

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Science China(Technological Sciences) 2023年第12期66卷 3504-3521页

作者： PAN ChaoFeng LI Yuan HUANG AiBao WANG Jian LIANG Jun automotive engineering Research Institute Jiangsu UniversityZhenjiang 212013China school of automotive and Traffic engineering Jiangsu UniversityZhenjiang 212013China

In this study, vehicle queuing was investigated at intersections to propose an eco-driving strategy to improve vehicle energy consumption and traffic efficiency in urban traffic environments. The proposed design approach can be applied to electric vehicles, and the control framework is categorized into two layers. In the upper layer, the speed of the host vehicle is planned offline, and in the lower layer, the required control variable acceleration is determined. First, the energy optimization problem of electric vehicles passing through an intersection was constructed, and the planning vehicle speed was obtained based on the genetic algorithm(GA). Next, the speed tracking controller and distance tracking controller were designed using sliding mode control(SMC) to ensure that the vehicle can track the planning speed with safe vehicle spacing. Finally, combined with specific cases, the energy-saving effect of the proposed method in the single-vehicle scenario, and the presence of manual driving vehicles in front-and multi-vehicle driving scenarios were studied. The results revealed that the GA-based single-vehicle speed planning method reduced energy consumption by up to 16% compared with the rule-based speed planning method. Furthermore,compared with the intelligent driver model(IDM) and adaptive cruise control(ACC) methods, the GA fleet speed planning method based on V2X communication can reduce average fleet energy consumption by 26% and 24%, respectively, and improve intersection traffic efficiency. The results of the sensitivity analysis of factors affecting planned speed revealed that vehicles passing through intersections at a steady speed exhibited superior economic performance. Finally, hardware-in-the-loop(HIL)testing was performed to verify the effectiveness of the controller under real-time conditions.

关键词： electric vehicle intersections eco-driving speed planning V2X sliding mode control

Investigation on hierarchical control for driving stability and safety of intelligent HEV during car-following and lane-change process

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Science China(Technological Sciences) 2022年第1期65卷 53-76页

作者： ZHOU YaZhou WANG RuoChen DING RenKai SHI DeHua YE Qing school of automotive and Traffic engineering Jiangsu UniversityZhenjiang 212013China automotive engineering Research Institute Jiangsu UniversityZhenjiang 212013China

The longitudinal and lateral coordinated control for autonomous vehicles is fundamental to achieve safe and comfortable driving performance.Aiming at this for hybrid electric vehicles(HEV)during the car-following(CF)and lane-change(LC)process while accelerating,a hierarchical control strategy for vehicle stability control is proposed.This new approach is different from the conventional hierarchical control.On the basis of model predictive control(MPC)theory,a two-layer MPC controller is designed at the top level of the control structure.The upper layer is a linear time-varying MPC(LTV-MPC),while the lower layer is a hybrid MPC(HMPC).For the LTV-MPC controller,a control-oriented linear discrete model for HEV is established,which integrates the dynamic model with three degrees of freedom(DOF)and the car-following model.The lower-layer HMPC controller is designed on the basis of the analysis for HEV hybrid characteristics and the modelling for the mixed logic dynamic(MLD)model of the HEV powertrain.As for the bottom level,a control plant including the HEV powertrain model and the 7 DOF nonlinear dynamics of the vehicle body is established.In addition,the system stability is proven.A deep fusion of vehicle dynamics control and energy management is achieved.Compared with LC-ACC control and conventional ACC control,the simulation and the hardware-in-the-loop(HIL)test results under different driving scenarios show that the proposed hierarchical control strategy can effectively maintain lateral stability and safety under severe driving conditions.Additionally,the HEV powertrain output torque and the gear-shift point are coordinated and controlled by the HMPC controller.

关键词： hybrid electric vehicle hierarchical control model predictive control mixed logical dynamic lane-change

Ce/Cu掺杂Fe-ZSM-5催化剂NH_(3)选择性催化还原NO_(x)的活性位点演化机理

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Journal of Central South University 2022年第7期29卷 2239-2252页

作者：张宇博王攀于丹赵虹钰吕星磊雷利利 school of automotive and Traffic engineering Jiangsu UniversityZhenjiang 212013China

通过水溶液离子交换法和初湿浸渍法制备Cu和Ce改性的Fe-ZSM-5催化剂,研究其在NH_(3)选择性催化还原NO_(x)中的作用。通过表征技术(NH_(3)-SCO,BET,XRD,XPS,UV-Vis,NH_(3)-TPD,H_(2)-TPR)探讨了催化剂活性位、酸性位和孔结构的变化,发现... 详细信息

通过水溶液离子交换法和初湿浸渍法制备Cu和Ce改性的Fe-ZSM-5催化剂,研究其在NH_(3)选择性催化还原NO_(x)中的作用。通过表征技术(NH_(3)-SCO,BET,XRD,XPS,UV-Vis,NH_(3)-TPD,H_(2)-TPR)探讨了催化剂活性位、酸性位和孔结构的变化,发现活性Cu物种和Fe物种的分散情况是影响整个催化过程中催化活性的重要因素。Fe-ZSM-5催化剂中Cu的掺杂带来了新的活性物种,孤立Cu离子和CuO颗粒,从而改善了低温催化活性。然而,催化剂的氨氧化作用也随之加强,催化剂中的部分Fe^(3+)活性位和Brønsted酸性位被Cu物种取代,这导致了高温活性的降低。进一步掺杂Ce后,高温活性得到恢复,可以归因于Ce促进了活性Cu物种和Fe物种的高度分散。这些发现为多金属掺杂调节铁基SCR催化剂的活性窗口提供了理论支持。

关键词：铁基分子筛氮氧化物脱除 Cu/Ce改性活性位点酸性位点

Correlation mechanism of friction behavior and topological properties of the contact network during powder compaction

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Particuology 2023年第11期82卷 98-110页

作者： Wei Zhang Chuanniu Yuan Shuai Zhang Weijian Xiao Ning Zhang Rongxin Chen school of Mechanical and automotive engineering Fujian University of TechnologyFuzhou350118China

The effect of friction behavior on the compacted density is significant, but the relationship between the topological properties of the contact network and friction behavior during powder compaction remains unclear. Based on the discrete element method (DEM), a DEM model for die compaction was established, and the Hertz contact model was modified into an elastoplastic contact model that was more suitable for metal-powder compaction. The evolution of the topological properties of the contact network and its mechanism during powder compaction was explored using the elastoplastic contact model. The results demonstrate that the friction behavior between the particles is closely related to the topological properties of the contact network. Side wall friction results in smaller clustering coefficient (CC) and excess contact (EC) in the lower region near the side wall. Corresponding to this phenomenon, the upper region near the side wall has more high-stress particles when the major principal stress threshold was considered, and the CC and EC are significantly higher than those in the other regions. This study provides a theoretical basis for improving powder compaction behavior.

关键词： Powdercompaction Granularmatter Discrete element method Topological property Friction behavior

A Study of the Effect of the Miller Cycle on the Combustion of a Supercharged Marine Diesel Engine

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Energy engineering 2024年第5期121卷 1363-1380页

作者： Lingjie Zhao Cong Li Mechanical and automotive engineering school Shanghai University of Engineering ScienceShanghai201600China

The Miller cycle is a program that effectively reduces NOx emissions from marine diesel engines by lowering the maximum combustion temperature in the cylinder,thereby reducing NOx emissions.To effectively investigate the impact of Miller cycle optimum combustion performance and emission capability under high load conditions,this study will perform a one-dimensional simulation of the performance of a marine diesel engine,as well as a threedimensional simulation of the combustion in the cylinder.A 6-cylinder four-stroke single-stage supercharged diesel engine is taken as the research object.The chassis dynamometer and other related equipment are used to build the test system,carry out the diesel engine bench test,and collect experimental data.The simulation results are compared with the test results,and the error is less than 5%.In this study,the authors will use simulation software to simulate several Miller cycle scenarios designed for early inlet valve closure and analyze the impact of the Miller cycle on combustion and emissions at 100%load conditions.By comparing the flow field distribution of the engine at 1500 r/min condition,it was found that proper EIVC can prolong the ignition latency period and homogeneous fuel-air mixture combustion acceleration,but it can reduce pressure and temperature within the piston chamber and NOx emission.However,the Miller cycle reduces end-of-compression temperatures,which increases combustion duration and exhaust temperatures,making it difficult to improve fuel economy at the optimum fuel consumption point,and closing the intake valves prematurely leads to excessive fuel expenditure.Furthermore,temperature and heat release rate within the piston chamber,NOx,and SOOT generation were significantly enhanced.

关键词： Miller cycle EIVC combustion NOx emissions marine diesel

新型螺旋非圆锥齿轮的数学模型和齿面接触分析

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Journal of Central South University 2022年第1期29卷 157-172页

作者：韩星会张轩诚郑方焱徐曼田俊 School of Automotive Engineering Hubei Key Laboratory of Advanced Technology of Automotive PartsWuhan University of TechnologyWuhan 430070China

本文结合非圆锥齿轮的设计原理和面铣螺旋锥齿轮的制造原理,提出了一种可应用于相交轴变速传动的新型螺旋非圆锥齿轮。与直齿非圆锥齿轮不同,螺旋非圆锥齿轮有许多优点,如高接触比、高强度、良好的动态性能和可调节的接触区域。此外,虽... 详细信息

本文结合非圆锥齿轮的设计原理和面铣螺旋锥齿轮的制造原理,提出了一种可应用于相交轴变速传动的新型螺旋非圆锥齿轮。与直齿非圆锥齿轮不同,螺旋非圆锥齿轮有许多优点,如高接触比、高强度、良好的动态性能和可调节的接触区域。此外,虽然制造直齿非圆锥齿轮很困难,但螺旋非圆锥齿轮可以用6轴锥齿轮切削机床高效、精确地制造。首先,介绍了螺旋非圆锥齿轮的产形原理。接着,建立了一个数学模型,包括产形齿的齿廓、齿轮螺旋度、压力角和该齿轮的产形齿廓。然后,利用有限元进行齿轮接触分析,验证了模型精度,并研究了螺旋非圆锥齿轮的接触模式和应力分布。

关键词：非圆形齿轮螺旋锥齿轮数学模型齿轮接触分析

A Deep Learning-Enabled Skin-Inspired Pressure Sensor for Complicated Recognition Tasks with Ultralong Life

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Research 2024年第1期2023卷 443-454页

作者： Yingxi Xie Xiaohua Wu Xiangbao Huang Qinghua Liang Shiping Deng Zeji Wu Yunpeng Yao Longsheng Lu school of Mechanical&automotive engineering South China University of TechnologyGuangzhouChina

Flexible full-textile pressure sensor is able to integrate with clothing directly,which has drawn extensive attention from scholars recently.But the realization of flexible full-textile pressure sensor with high sensitivity,wide detection range,and long working life remains challenge.Complex recognition tasks necessitate intricate sensor arrays that require extensive data processing and are susceptible to damage.The human skin is capable of interpreting tactile signals,such as sliding,by encoding pressure changes and performing complex perceptual tasks.Inspired by the skin,we have developed a simple dip-and-dry approach to fabricate a full-textile pressure sensor with signal transmission layers,protective layers,and sensing layers.The sensor achieves high sensitivity(2.16 kPa^(−1)),ultrawide detection range(0 to 155.485 kPa),impressive mechanical stability of 1 million loading/unloading cycles without fatigue,and low material cost.The signal transmission layers that collect local signals enable real-world complicated task recognition through one single sensor.We developed an artificial Internet of Things system utilizing a single sensor,which successfully achieved high accuracy in 4 tasks,including handwriting digit recognition and human activity recognition.The results demonstrate that skin-inspired full-textile sensor paves a promising route toward the development of electronic textiles with important potential in real-world applications,including human–machine interaction and human activity detection.

关键词： Deep Skin utilizing