Maintenance management balanced scorecard approach for urban transport fleets

[EN] Attending the important role of maintenance function in any production or service provider company, the measurement and assessment of maintenance performance is crucial for competitiveness and future survival. That situation is even more critical in urban transport fleets where some specific boundary conditions and special characteristics will affect maintenance policy and implementation. This paper presents a deep review of different studies worldwide to define the most proper and effective maintenance performance indicators, selecting and refining the most important ones to obtain a reduced maintenance management balanced scorecard. That balanced scorecard is proposed as a main tool for urban transport fleet maintenance managers to assess efficiency and effectiveness of maintenance processes and will be used as a basis for a future benchmarking process for this type of companies.Authors want to acknowledgement to EMT de Valencia and other ATUC company members their collaboration and involvement on works performed during the project for KPIs definition and selection. Special thanks to Engineer Santiago Ballester for sharing efforts and knowledge to develop that work.Macian Martinez, V.; Tormos, B.; Herrero, J. (2019). Maintenance management balanced scorecard approach for urban transport fleets. Eksploatacja i Niezawodnosc - Maintenance and Reliability. 21(2):226-236. https://doi.org/10.17531/ein.2019.2.6S22623621

Large Eddy Simulation for high pressure flows: Model extension for compressible liquids

[EN] The present study gives a general outline for the fluid-dynamical calculation of flows at high pressure conditions. The main idea is to present a mathematical description of high pressure processes in liquids at compressible conditions, quantifying the effect of density variations on the flow pattern due to those pressure variations. The improved mathematical approach is coupled to a Large Eddy Simulation (LES) solver. The main code was developed by OpenSource Ltd. for OpenFOAM, and the authors have introduced the additional expressions in order to calculate particular variables. For validating the code improvement, the LES solver is applied to a modern common-rail nozzle injector used in diesel engines. Results have been compared against other calculations that assumed constant properties and simultaneously validated with experimental data. © 2010 Elsevier Ltd.This work has been funded by MINISTERIO DE CIENCIA E INNOVACION from Spain, in the framework of the project “ESTUDIO TEORICO EXPERIMENTAL DE LA INFLUENCIA DEL COMBUSTIBLE SOBRE LA CAVITACION Y EL DESARROLLO DEL CHORRO EVAPORATIVO”, Reference No. TRA2010-17564. The authors would like to thank Universidad de Valencia for the computer resources, technical expertise, the assistance provided and for allowing the use of the supercomputer Tirant.Payri, R.; Tormos, B.; Gimeno, J.; Bracho Leon, G. (2011). Large Eddy Simulation for high pressure flows: Model extension for compressible liquids. Mathematical and Computer Modelling. 54(7):1725-1731. https://doi.org/10.1016/j.mcm.2010.12.001S1725173154

Improving the quantification of land cover pressure on stream ecological status at the riparian scale using High Spatial Resolution Imagery

The aim of this paper is to demonstrate the interest of High Spatial Resolution Imagery (HSRI) and the limits of coarse land cover data such as CORINE Land Cover (CLC), for the accurate characterization of land cover structure along river corridors and of its functional links with freshwater ecological status on a large scale. For this purpose, we compared several spatial indicators built from two land cover maps of the Herault river corridor (southern France): one derived from the CLC database, the other derived from HSRI. The HSRI-derived map was obtained using a supervised object-based classification of multi-source remotely-sensed images (SPOT 5 XS-10 m and aerial photography-0.5 m) and presents an overall accuracy of 70 %. The comparison between the two sets of spatial indicators highlights that the HSRI-derived map allows more accuracy in the quantification of land cover pressures near the stream: the spatial structure of the river landscape is finely resolved and the main attributes of riparian vegetation can be quantified in a reliable way. The next challenge will consist in developing an operational methodology using HSRI for large-scale mapping of river corridor land cover,, for spatial indicator computation and for the development of related pressure/impact models, in order to improve the prediction of stream ecological status

Experimental assessment and validation of an oil ferrous wear debris sensors family for wind turbine gearboxes

[EN] Purpose - The purpose of this study was to perform a complete experimental assessment of a family of oil ferrous wear debris sensor is performed. The family comprised the original sensor and its re-engineered evolution, which is capable of detecting both amount and size of wear debris particles trapped by the sensor and some predefined oil condition properties. Design/methodology/approach ¿ In this work, the first step was to perform a design of experiments for the sensor validation. A specially defined test rig was implemented, and different ferrous wear debris was collected. For each sensor, two different tests were performed. The first test was called a ¿void test¿, where quantified amounts of debris were collided with the sensor without oil. The second one was a dynamic test, where the sensor was installed in the test rig and different amounts of wear debris were added at a constant rate. In addition, specific tests related with oil properties detection were studied. Findings ¿ The results show excellent correlation of the sensor output signal with the amount of wear debris and a satisfactory detection of debris size in all ranges. Also, the dynamic test presented adequate representativeness, and sensors performed well in this scenario. Practical implications ¿ This paper shows the practical implementation of this type of sensor and the usual detection range and rate of detection for different debris size and quantities. Originality/value ¿ This work has a great utility for maintenance managers and equipment designers to fully understand the potential of this type of sensor and its suitability for the application required.Authors would like to thank Iberdrola Generacion S.A. for their support in this project and Universitat Politecnica de Valencia for its support through contract FPI-S2-2015-1065 of Programa de Apoyo para la Investigacion y Desarrollo (PAID). Additionally, the authors would like to especially thank Daniel Veintimilla for their help in this work.Macian Martinez, V.; Tormos, B.; Miró Mezquita, G.; Rodes, I. (2018). Experimental assessment and validation of an oil ferrous wear debris sensors family for wind turbine gearboxes. Sensor Review. 38(1):84-91. https://doi.org/10.1108/SR-04-2017-0065S8491381Chiou, Y.-C., Lee, R.-T., & Tsai, C.-Y. (1998). An on-line Hall-effect device for monitoring wear particle in oils. Wear, 223(1-2), 44-49. doi:10.1016/s0043-1648(98)00289-0Du, L., & Zhe, J. (2011). A high throughput inductive pulse sensor for online oil debris monitoring. Tribology International, 44(2), 175-179. doi:10.1016/j.triboint.2010.10.022Holmberg, K., Adgar, A., Arnaiz, A., Jantunen, E., Mascolo, J., & Mekid, S. (Eds.). (2010). E-maintenance. doi:10.1007/978-1-84996-205-6Sheng, S. (2013), Report on Wind Turbine Subsystem Reliability - A Survey of Various Databases, NREL/PR-5000-59111

Energy Management of Hybrid Electric Urban Bus by Off-Line Dynamic Programming Optimization and One-Step Look-Ahead Rollout

[EN] Due to the growing air quality concern in urban areas and rising fuel prices, urban bus fleets are progressively turning to hybrid electric vehicles (HEVs) which show higher efficiency and lower emissions in comparison with conventional vehicles. HEVs can reduce fuel consumption and emissions by combining different energy sources (i.e., fuel and batteries). In this sense, the performance of HEVs is strongly dependent on the energy management strategy (EMS) which coordinates the energy sources available to exploit their potential. While most EMSs are calibrated for general driving conditions, this paper proposes to adapt the EMS to the specific driving conditions on a particular bus route. The proposed algorithm relies on the fact that partial information on the driving cycle can be assumed since, in the case of a urban bus, the considered route is periodically covered. According to this hypothesis, the strategy presented in this paper is based on estimating the driving cycle from a previous trip of the bus in the considered route. This initial driving cycle is used to compute the theoretical optimal solution by dynamic programming. The obtained control policy (particularly the cost-to-go matrix) is stored and used in the subsequent driving cycles by applying one-step look-ahead roll out, then, adapting the EMS to the actual driving conditions but exploiting the similarities with previous cycles in the same route. To justify the proposed strategy, the paper discusses the common patterns in different driving cycles of the same bus route, pointing out several metrics that show how a single cycle captures most of the key parameters for EMS optimization. Then, the proposed algorithm (off-line dynamic programming optimization and one-step look-ahead rollout) is described. Results obtained by simulation show that the proposed method is able to keep the battery charge within the required range and achieve near-optimal performance, with only a 1.9% increase in fuel consumption with regards to the theoretical optimum. As a reference for comparison, the equivalent consumption minimization strategy (ECMS), which is the most widespread algorithm for HEV energy management, produces an increase in fuel consumption with respect to the optimal solution of 11%.This research was funded by Ministerio de Ciencia e Innovacion, through the Proyectos I+D+i 2020 Program, grant number PID2020-119691RB-I00.Tormos, B.; Pla Moreno, B.; Bares-Moreno, P.; Pinto, D. (2022). Energy Management of Hybrid Electric Urban Bus by Off-Line Dynamic Programming Optimization and One-Step Look-Ahead Rollout. Applied Sciences. 12(9):1-19. https://doi.org/10.3390/app1209447411912

Proposal of an FTIR Methodology to Monitor Oxidation Level in Used Engine Oils: Effects of Thermal Degradation and Fuel Dilution

This article describes a procedure, based on ASTM standards D7214 and E2412, that has been defined to improve quantification of oil oxidation in used engine oils. Taking into account typical problems that can be found in this type of sample, including thermal oxidation and fuel dilution, Fourier transform infrared (FTIR) spectra were analyzed also considering the effect of the oil formulation. Two zones were considered inside the typical wave number range for quantification of oxidation, where those problems can be detected and assessed more easily: zone A between 1725 and 1650 cm-1, where the main oxidation products, such as aldehydes, carboxylic acids, and ketones, occur due to thermal degradation of the oil; and zone B between 1770 and 1725 cm-1, where esters due to potential biodiesel dilution problems are detected. Copyright © Society of Tribologists and Lubrication Engineers.The authors are grateful for Spanish Grant TRA2008-06508 (GLAUTO) from the Ministerio de Ciencia e Innovacion-Direccion General de Investigacion for supporting this work.Macian Martinez, V.; Tormos, B.; Gomez Estrada, YA.; Salavert Fernández, JM. (2012). Proposal of an FTIR Methodology to Monitor Oxidation Level in Used Engine Oils: Effects of Thermal Degradation and Fuel Dilution. Tribology Transactions. 55(6):872-882. https://doi.org/10.1080/10402004.2012.721921S87288255

Model optymalizacji czasuwymiany floty. Analiza porównawcza flot miejskiego transportu publicznego z zastosowaniem symulacji Monte Carlo

[Otro] W niniejszej pracy przedstawiono analiz¿ kosztów pracy i utrzymania flot transportowych w dwóch krajach: Hiszpanii i Brazylii. Dla celów analizy, zaproponowano model optymalizacji stanowi¿cy po¿¿czenie tradycyjnej Analizy Kosztów Cyklu ¿ycia (LCC) oraz modelu symulacji Monte Carlo. wyniki potwierdzi¿y trafno¿¿ modelu oraz pokaza¿y, ¿e koszty ponoszone w przypadku floty brazylijskiej by¿y ni¿sze. Zaproponowany model mo¿e znale¿¿ zastosowanie zarówno w praktyce jak i w dalszych badaniach.[EN] This paper presents a comparative analysis of operation and maintenance costs of the transport fleets in two countries: Spain and Brazil. For this analysis, the research proposed an optimization model which is a combination of the traditional Life Cycle Cost Analysis methodology (LCC) and simulation model Monte Carlo. The results indicated the successful of model and show the lower cost in the Brazilian fleet. The evidences may be useful for other practices and researches.Macian Martinez, V.; Tormos, B.; De Sa-Riechi, JL. (2017). Time Replacement Optimization Model: Comparative Analysis of Urban Transport Fleets Using Monte Carlo Simulation. Eksploatacja i Niezawodnosc - Maintenance and Reliability. 19(2):151-157. doi:10.17531/ein.2017.2.1S15115719

Improved fleet operation and maintenance through the use of low viscosity engine oils: fuel economy and oil performance

[EN] For heavy-duty vehicles and road transportation, fuel consumption and associated CO2 emissions have been of great concern, which has led to the development and implementation of technologies to reduce their impact on the environment. Low viscosity engine oils have arisen as one proven cost-effective solution to increase the engine efficiency; however, for the heavy-duty vehide segment, engine protection against wear is a priority for end-users, and therefore there is some reluctance to the use of that new oil formulations. In this study, eight lubricant oils, representative of the HTHS viscosity reduction that heavy-duty oils have been undergoing and new API CK-4 and FA-4 categories, were evaluated for fuel economy, oil performance and engine wear, in a long-term test involving a fleet of 49 heavy-duty vehicles of four different engine technologies, some of them with diesel fuel and others with compressed natural gas. Results of fuel economy were positive for most of the buses' models. Regarding oil performance and wear, most of the formulations were found to be suitable for extended oil drain intervals (ODI); and although no alarming results were found, overall performance of the formulations of the fourth stage could lead to significant wear if the oil drain interval is extended. In this study, it should be noted that some of the information has been presented by the authors in other publications, here they are presented with the purpose of complementing the new results and summarize the entire test.Author Sophia Bastidas would like to thank the support of the program Ayudas de Investigacion y Desarrollo (PAID-01-17) of the Universitat Politecnica de Valencia.Macian Martinez, V.; Tormos, B.; Bastidas-Moncayo, KS.; Pérez, T. (2020). Improved fleet operation and maintenance through the use of low viscosity engine oils: fuel economy and oil performance. Eksploatacja i Niezawodnosc - Maintenance and Reliability. 22(2):201-211. https://doi.org/10.17531/ein.2020.2.3S20121122

One-Dimensional Modeling of Mechanical and Friction Losses Distribution in a Four-Stroke Internal Combustion Engine

[EN] As the road transport accounts between 15%-18% of worldwide CO2 emissions, the automotive sector has a deep commitment to mitigate global warming. Consequently, stricter regulations have been adopted by the European Union and worldwide to reduce that big impact. Approximately, 10% of the energy generated by fuel combustion in the engine is destined to the auxiliaries components activation and the movement of mechanical elements with relative motion between themselves. A reduction on that figure or alternatively a mechanical efficiency improvement can be directly translated on target alignment. The aim of this work is developing a model to predict the mechanical and friction losses and its distribution in a four-stroke direct injection-diesel engine and simulating different strategies, which increment the engine efficiency. A 1D model has been developed and fitted in GT-SUITE based on the experimental results of a 1.6-L diesel engine. Additionally, a description of the tribological performance has been realized in different parts of the engine where friction is present. Finally, the engine friction maps have been broken down in order to quantify the friction losses produced in the piston ring assembly, crankshaft bearings, and valvetrainTormos, B.; Martín, J.; Blanco-Cavero, D.; Jiménez-Reyes, AJ. (2020). One-Dimensional Modeling of Mechanical and Friction Losses Distribution in a Four-Stroke Internal Combustion Engine. Journal of Tribology. 142(1). https://doi.org/10.1115/1.4044856S142

Current trends in ICE wear detection technologies: from lab to field

[EN] Research in internal combustion engine (ICE) tribology has been an active topic during the last decades, driven by different interest: first, in order to improve thermodynamics and overall engine performance, while nowadays there is an interest in reducing engine losses, including friction, in order to cut down fuel consumption and also exhaust emissions. Tribology is a tri-vector science, where friction is the fundamental phenomena occurring between two surfaces, wear is the consequence of the occurrence of friction and lubrication is the solution for diminish friction and eliminate wear presence in the tribological system. During the development of ICE, different technologies and techniques have been applied for detection of ICE wear, focused in different parts of the engine life and also used for different purposes, including research or maintenance. In this work, a comprehensive look on this field is done, where several techniques are explained and their main application and pros and cons are highlighted.CMT-Motores Térmicos would like to thank the Spanish Ministerio de Ciencia e Innovación for its funding (Project no. TRA2015-70785-R) and Universitat Politècnica de València for its support through contract FPI-S2-2015-1065 of Programa de Apoyo para la Investigación y Desarrollo (PAID). The virtual vehicle research center acknowledges the financial support of the Austrian Science Fund (FWF): P27806-N30. Partial support was obtained from the "COMET - Competence Centers for Excellent Technologies Programme" of the Austrian Federal Ministry for Transport, Innovation and Technology (bmvit), the Austrian Federal Ministry of Science, Research and Economy (bmwfw), the Austrian Research Promotion Agency (FFG), the Province of Styria and the Styrian Business Promotion Agency (SFG).Miró Mezquita, G.; Tormos, B.; Allmaier, H.; Sander, D.; Knauder, C. (2017). Current trends in ICE wear detection technologies: from lab to field. ASRO Journal of Applied Mechanics. 2(1):32-41. http://hdl.handle.net/10251/151294S32412