18 research outputs found
Data driven techniques for on-board performance estimation and prediction in vehicular applications.
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
Data-Driven Model for Real-Time Estimation of NOx in a Heavy-Duty Diesel Engine
No full textThe automotive sector is greatly contributing to pollutant emissions and recent regulations introduced the need for a major control of, and reduction of, internal combustion engine emissions. Artificial intelligence (AI) algorithms have proven to hold the potential to be the thrust in the state-of-the-art for engine-out emission prediction, thus enabling tailored calibration modes and control solutions. More specifically, the scientific literature has recently witnessed strong efforts in AI applications for the development of nitrogen oxides (NOx) virtual sensors. These latter replace physical sensors and exploit AI algorithms to estimate NOx concentrations in real-time. Still, the calibration of the algorithms, together with the appropriate choice of the specific metric, strongly affects the prediction capability. In the present paper, a machine learning-based virtual sensor for NOx monitoring in diesel engines was developed, based on the Extreme Gradient Boosting (XGBoost) machine learning algorithm. The latter is commonly used in the literature to deploy virtual sensors due to its high performance, flexibility and robustness. An experimental campaign was carried out
to collect data from the engine test bench, as well as from the engine electronic control unit (ECU), for the development and calibration of the virtual sensor at steady-state conditions. The virtual sensor has, since then, been tested throughout on an on-road driving mission to assess its prediction
performance in dynamic conditions. In stationary conditions, its prediction accuracy was around 98%, whereas it was 85% in transient conditions. The present study shows that AI-based virtual sensors have the potential to significantly improve the accuracy and reliability of NOx monitoring in diesel
engines, and can, therefore, play a key role in reducing NOx emissions and improving air quality
Reducing the computational cost for artificial intelligence-based battery state-of-health estimation in charging events
No full textPowertrain electrification is bound to pave the way for the decarbonization process and pollutant emission reduction of the automotive sector, and strong attention should hence be devoted to the electrical energy storage system. Within such a framework, the lithium-ion battery plays a key role in the energy scenario, and the reduction of lifetime due to the cell degradation during its usage is bound to be a topical challenge. The aim of this work is to estimate the state of health (SOH) of lithium-ion battery cells with satisfactory accuracy and low computational cost. This would allow the battery management system (BMS) to guarantee optimal operation and extended cell lifetime. Artificial intelligence (AI) algorithms proved to be a promising data-driven modelling technique for the cell SOH prediction due to their great suitability and low computational demand. An accurate on-board SOH estimation is achieved through the identification of an optimal SOC window within the cell charging process. Several Bi-LSTM networks have been trained through a random-search algorithm exploiting constant current constant voltage (CCCV) test protocol data. Different analyses have been performed and evaluated as a trade-off between prediction performance (in terms of RMSE and customized accuracy) and computational burden (in terms of memory usage and elapsing time). Results reveal that the battery state of health can be predicted by a single-layer Bi-LSTM network with an error of 0.4% while just monitoring 40% of the entire charging process related to 60–100% SOC window, corresponding to the constant-voltage (CV) phase. Finally, results show that the amount of memory used for data logging and processing time has been cut by a factor of approximately 2.3
Modeling and On-Road Testing of an Electric Two-Wheeler towards Range Prediction and BMS Integration
No full textThe automotive sector is currently shifting its focus from traditional fossil fuels to electrification. The deployment of a Battery Management System (BMS) unit is the key point to oversee the battery state of the electric vehicle (EV) to ensure safety and performances. The development and assessment of electric vehicle models in turn lays the groundwork of the BMS design as it provides a quick and cheap solution to test battery optimal control logics in a Software-in-the-Loop environment. Despite the various contribution to the literature in battery and vehicle modeling, electric scooters are mostly disregarded together with a reliable estimation of their performance and electric range. The present paper hence aims at filling the gap of knowledge through the development of a numerical model for considering a two-wheeler. The latter model relies on the conservation energy based-longitudinal dynamic approach and is coupled to a Li-Ion Battery second-order RC equivalent circuit model for the electric range prediction. More specifically, the presented work assesses the performance and electric range of a two-wheeler pure electric scooter in a real-world driving cycle. The e-powertrain system embeds an Electrical Energy Storage System (EESS) Li-Ion Battery pack. On-road tests were initially conducted to retrieve the main model parameters and to perform its validation. A global battery-to-wheels efficiency was also calibrated to account for the percentual amount of available net power for the vehicle onset. The model proved to properly match the experimental data in terms of total distance traveled over a validation driving mission
Comparing Parallel Hybrid Electric Vehicle Powertrains for Real-world Driving
No full textParallel configurations are listed among the most promising hybrid electric vehicle (HEV) architectures. However, their potential impact both on the reduction of CO 2 and the total vehicle cost still requires additional and comprehensive evaluation. This paper therefore aims at comparing several parallel HEV architectures to assess for their CO 2 emission reduction potential, drivability capabilities and total cost of ownership (TCO) with respect to conventional layouts. Both standard drive cycles and real-world driving missions have been analyzed and two different vehicles have been selected for the study. The obtained results demonstrate how parallel hybridization may remarkably improve both fuel economy and drivability capability compared to conventional internal combustion engine vehicles. Despite parallel HEVs present a higher purchasing cost, the latter can be efficiently recuperated over the vehicle lifetime. Finally, P2 architecture appears as the most favorable parallel HEV configuration according to the considered analysis parameters
Alternating optimization of design and stress for stress-constrained topology optimization
No full textHandling stress constraints is an important topic in topology optimization. In this paper, we introduce an interpretation of stresses as optimization variables, leading to an augmented Lagrangian formulation. This formulation takes two sets of optimization variables, i.e., an auxiliary stress variable per element, in addition to a density variable as in conventional density-based approaches. The auxiliary stress is related to the actual stress (i.e., computed by its definition) by an equality constraint. When the equality constraint is strictly satisfied, an upper bound imposed on the auxiliary stress design variable equivalently applies to the actual stress. The equality constraint is incorporated into the objective function as linear and quadratic terms using an augmented Lagrangian form. We further show that this formulation is separable regarding its two sets of variables. This gives rise to an efficient augmented Lagrangian solver known as the alternating direction method of multipliers (ADMM). In each iteration, the density variables, auxiliary stress variables, and Lagrange multipliers are alternatingly updated. The introduction of auxiliary stress variables enlarges the search space. We demonstrate the effectiveness and efficiency of the proposed formulation and solution strategy using simple truss examples and a dozen of continuum structure optimization settings.Accepted Author ManuscriptMaterials and Manufacturin
Topology Optimization of Differentiable Microstructures
No full textRecent years have seen a growing interest in topology optimization of functionally graded microstructures, characterized by an array of microstructures with varying volume fractions. However, microstructures optimized at slightly different volume fractions do not necessarily connect well when placed adjacently. Furthermore, optimization is commonly performed on a finite set of volume fractions, limiting the number of microstructure configurations. In this paper, we introduce the concept of differentiable microstructures, which are parameterized microstructures that exhibit continuous variations in both geometry and mechanical properties. To construct such microstructures, we propose a novel formulation for topology optimization. In this approach, a series of 2-dimensional microstructures is represented using a height field, and the objective is to maximize the bulk modulus of the entire series. Through this optimization process, an initial microstructure with a small volume fraction undergoes non-uniform transformations, generating a series of microstructures with progressively increasing volume fractions. Notably, when compared to traditional uniform morphing methods, our proposed optimization approach yields a series of microstructures with bulk moduli that closely approach the theoretical limit.</p
Role of moving planes and moving spheres following Dupin cyclides
No full textWe provide explicit representations of three moving planes that form a μ-basis for a standard Dupin cyclide. We also show how to compute μ-bases for Dupin cyclides in general position and orientation from their implicit equations. In addition, we describe the role of moving planes and moving spheres in bridging between the implicit and rational parametric representations of these cyclides. © 2014 Elsevier B.V.The author is grateful to professor Falai Chen and professor Ron Goldman for their guidance on the topic of A-bases through years. Zhouwang Yang at the University of Science and Technology of China proposed the original idea in Section 6 two years ago in another project. This work is supported by a National Key Basic Research Project of China (2011CB302404), by grants from NSFC (11201463), (60821002) and (91118001). The author is also supported by the National Center for Mathematics and Interdisciplinary Sciences in the Chinese Academy of Sciences and KAUST base funding
A gyakorlatias angol jogászképzés kialakulása az Inns of Court falai között
No full textProfessor Lajos Besenyei the anniversary celebrated, has also become known at the Faculty of Law, — the other historical, provincial one — in Pécs that he as a lecturer giving exams is a rigorous examiner requiring high standards from students. Students coming from other faculties to pursue their studies in Pécs are as a rule obliged to take a so called difference-exam in civil law as in other subjects due to the material differences in curriculum. While being examined it has been often mentioned by students coming from Szeged that they were not expected to learn the material of text books in civil law but it was quite enough if they knew the merit of Hungarian Civil Code and had a thorough knowledge of the lectures given by Professor Besenyei. Despite these statements of the students which are of course not objective necessarily one can be positive that the actually celebrated Professor is the real master of practical legal education. This is the reason why I chose a topic which can be related to the personal and professional attitudes of Lajos Besenyei. The current paper aims to present the origins and the development of the practical legal teaching in England inside the walls of the Inns of Court. The author also would like to address this paper to the memory of Professor György Bónis and Professor Elemér Pólay the legendary late representatives of the famous private law history tradition in Szeged. Professor Bónis also carried on researches in connection with the main issue of the current paper. His scientific considerations and results are broadly utilised in this paper also. The paper covers the following topics: the origins and the development of the practical legal teaching in England and its characteristics, the development of the institution of the Inns of Court, the role of the Inns of Chancery and the Serjeants' Inn; the membership of the English law society and its status: the bar and the bench; the serjeants at laws, the apprentices, the benchers, the attorneys, the solicitors, the inner and the outer barristers; the form of the legal and professional education: the Inns of Court and the universities; the dinings, the practical legal teaching in the XX. century
József Wohlmuth as School Inspector in the Pannonhalma Saint Benedict Order
No full textA pannonhalmi apátságot Géza fejedelem alapította, felépítése Szent István királynak köszönhető. A szerzetesek a templom falai között létrehozott iskolában végezték a vallásos nevelést és oktatást, közvetítették a kultúrát. Nemcsak a kolostoron belül, hanem István király által adományozott birtokaikon is tanítottak.The Hungarian Saint Benedict Order’s Monastery of Pannonhalma has been preserving our nation’s culture and also serving the spiritual needs of Hungarian Catholics for over a thousand year. The first church school was established in Pannonhalma in 996. This foundation of the monastery was instrumental in the development of society. The orders achieved favourable results in teacher training, such as elementary school education and secondary teaching. The author in his study examines an important period of the Catholic public schools’ supervision and control system of Pannonhalma Saint Benedict Order between the two World Wars. Between 1922 and 1931 József Wolmuth worked as primary education school inspector, and introduced significant changes. Not only had he monitored, but also helped the work of teachers. He established the Organization of Teachers of Pannonhalma Saint Benedict Order, which had a great impact on the professional development of teachers, the fast information changes between the schools and the governance, and the democratization of the control of public education
