Effectiveness of hybrid powertrains to reduce the fuel consumption and NOx emissions of a Euro 6d-temp diesel engine under real-life driving conditions

[EN] Recent investigations demonstrated that the real-world driving conditions differ from those proposed in the homologation cycles. This provokes that the emissions levels in real-life conditions exceed the normative values, as shown in the recent scandal related to the NOx emissions from the passenger cars equipped with diesel engines. On the other hand, the upcoming emissions regulations will limit the CO2 emissions to very low levels, which demands a further optimization of the existing technology. One way to reduce the NOx and CO2 emissions is by electrifying the powertrain in a certain degree. The objective of this work is to evaluate the potential of implementing a parallel (P2) hybrid architecture in a compact car (class C) equipped with a diesel 1.6 Euro 6d-temp engine to reduce the emissions and fuel consumption in homologation and real-life driving cycles. This has been done using a OD numerical vehicle model and the experimental engine maps of fuel consumption and emissions measured at steady state conditions. After that, the transient conditions were simulated in homologation cycles and real-life driving cycles measured by the authors in Spain. The numerical model was validated against experimental tests carried out in an active engine test bench, evidencing differences below 4% under the worldwide harmonized light vehicles test cycle (WLTC). In the real-life cycles, the hybridization of the powertrains improves the fuel consumption for all types of driving cycles (urban, combined and highway). The major benefits are obtained in urban driving cycles, with gains up to 50% in fuel consumption and CO2 emissions. In addition, the improvements in real-life conditions are higher than in the urban phase of the homologation cycles. On the contrary, combined real-life cycles (urban + rural + highway) show lower benefits than the homologation cycle. This is due to different energy management strategy that needs to be adapted to each driving situation. Lastly, it was found that, contrarily to the case of the homologation cycle, the NOx emissions are not reduced with the hybridization of the diesel powertrain in real-life conditions. Thus, to achieve 2021 CO2 target (95 g/km) and to reduce aftertreatment systems in diesel engines, other vehicles technologies need to be added to the full hybridization.The authors acknowledge FEDER and Spanish Ministerio de Economia y Competitividad for partially supporting this research through TRANCO project (TRA2017-87694-R). The authors also acknowledge the Universitat Politecnica de Valencia for partially supporting this research through Convocatoria de ayudas a Primeros Proyectos de Investigacion (PAID-06-18).Luján, JM.; García Martínez, A.; Monsalve-Serrano, J.; Martínez-Boggio, S. (2019). Effectiveness of hybrid powertrains to reduce the fuel consumption and NOx emissions of a Euro 6d-temp diesel engine under real-life driving conditions. Energy Conversion and Management. 199:1-18. https://doi.org/10.1016/j.enconman.2019.111987S11819

Geomatic methods applied to the change study of the la Paúl Rock Glacier, Spanish Pyrenees

Producción CientíficaRock glaciers are one of the most important features of the mountain permafrost in the Pyrenees. La Paúl is an active rock glacier located in the north face of the Posets massif in the La Paúl glacier cirque (Spanish Pyrenees). This study presents the preliminary results of the La Paúl rock glacier monitoring works carried out through two geomatic technologies since 2013: Global Navigation Satellite System (GNSS) receivers and Terrestrial Laser Scanning (TLS) devices. Displacements measured on the rock glacier surface have demonstrated both the activity of the rock glacier and the utility of this equipment for the rock glaciers dynamic analysis. The glacier has exhibited the fastest displacements on its west side (over 35 cm yr-1), affected by the Little Ice Age, and frontal area (over 25 cm yr-1). As an indicator of permafrost in marginal environments and its peculiar morphology, La Paúl rock glacier encourages a more prolonged study and to the application of more geomatic techniques for its detailed analysis.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project CGL2015-68144-R)Junta de Extremadura - Fondo Europeo de Desarrollo Regional (project GR10071

Influence of Doping and Nanostructuration on n-Type Bi2(Te0.8Se0.2)3 Alloys Synthesized by Arc Melting

In competitive thermoelectric devices for energy conversion and generation, high-efficiency materials of both n-type and p-type are required. For this, Bi2Te3-based alloys have the best thermoelectric properties in room temperature applications. Partial replacement of tellurium by selenium is expected to introduce new donor states in the band gap, which would alter electrical conductivity and thermopower. We report on the preparation of n-type Bi2(Te1-xSex)3 solid solutions by a straightforward arc-melting technique, yielding nanostructured polycrystalline pellets. X-ray and neutron powder diffraction was used to assess Se inclusion, also indicating that the interactions between quintuple layers constituting this material are weakened upon Se doping, while the covalency of intralayer bonds is augmented. Moreover, scanning electron microscopy shows large surfaces perpendicular to the c crystallographic axis assembled as stacked sheets. Grain boundaries related to this 2D nanostructuration affect the thermal conductivity reducing it below 0.8 Wm−1K−1 at room temperature. Furthermore, Se doping increases the absolute Seebeck coefficient up to −140 μV K−1 at 400 K, which is also beneficial for improved thermoelectric efficiency.This research was funded by the Spanish Ministry of Economy and Competitivity for granting the project MAT2013-41099-R.Peer reviewe

Linear Strain Tensors on Hyperbolic Surfaces and Asymptotic Theories for Thin Shells

We perform a detailed analysis of the solvability of linear strain equations on hyperbolic surfaces. We prove that if the surface is a smooth noncharacteristic region, any first order infinitesimal isometry can be matched to an infinitesimal isometry of an arbitrarily high order. The implications of this result for the elasticity of thin hyperbolic shells are discussed

Application of a one-dimensional spray model to teach diffusion flame fundamentals for engineering students

[EN] This study presents the application of an existing interactive application for teaching spray dynamics in engineering degrees. The model is based on spray momentum conservation and can be used to evaluate both fuel-air mixing characteristics in inert conditions as well as diffusion flame performance once combustion takes place. During a dedicated computer-lab session, the students perform parametric studies regarding the influence of the nozzle outlet diameter, the combustion chamber density and the spray cone opening angle on the mixing process, characterized by the maximum stoichiometric length. Later on, the effect of the combustion reaction on the mixing field is evaluated. The results are analyzed taking as a reference to the theoretical development made by Spalding and Schlichting for diffusion gas jets. The outcomes of several years using this technique are reported.García-Oliver, JM.; García Martínez, A.; De La Morena, J.; Monsalve-Serrano, J. (2019). Application of a one-dimensional spray model to teach diffusion flame fundamentals for engineering students. Computer Applications in Engineering Education. 27(5):1202-1216. https://doi.org/10.1002/cae.22146S12021216275Aleiferis, P. G., Behringer, M. K., & Malcolm, J. S. (2016). Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine. Flow, Turbulence and Combustion, 98(2), 523-577. doi:10.1007/s10494-016-9775-9Battin-Leclerc, F. (2008). Detailed chemical kinetic models for the low-temperature combustion of hydrocarbons with application to gasoline and diesel fuel surrogates. Progress in Energy and Combustion Science, 34(4), 440-498. doi:10.1016/j.pecs.2007.10.002Burke, R. D., De Jonge, N., Avola, C., & Forte, B. (2017). A virtual engine laboratory for teaching powertrain engineering. Computer Applications in Engineering Education, 25(6), 948-960. doi:10.1002/cae.21847Desantes, J. M., Pastor, J. V., García-Oliver, J. M., & Briceño, F. J. (2014). An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays. Combustion and Flame, 161(8), 2137-2150. doi:10.1016/j.combustflame.2014.01.022Desantes, J. M., Pastor, J. V., García-Oliver, J. M., & Pastor, J. M. (2009). A 1D model for the description of mixing-controlled reacting diesel sprays. Combustion and Flame, 156(1), 234-249. doi:10.1016/j.combustflame.2008.10.008Dumouchel, C., Cousin, J., & Triballier, K. (2005). On the role of the liquid flow characteristics on low-Weber-number atomization processes. Experiments in Fluids, 38(5), 637-647. doi:10.1007/s00348-005-0944-1Edmonds, E. (1980). Where Next in Computer Aided Learning? British Journal of Educational Technology, 11(2), 97-104. doi:10.1111/j.1467-8535.1980.tb00396.xFansler, T. D., & Parrish, S. E. (2014). Spray measurement technology: a review. Measurement Science and Technology, 26(1), 012002. doi:10.1088/0957-0233/26/1/012002Gutiérrez-Romero, J. E., Zamora-Parra, B., & Esteve-Pérez, J. A. (2016). Acquisition of offshore engineering design skills on naval architecture master courses through potential flow CFD tools. Computer Applications in Engineering Education, 25(1), 48-61. doi:10.1002/cae.21778IPCC. Intergovernmental Panel on Climate Change Working Group I. Climate Change 2013: The Physical Science Basis.Long‐term Climate Change: Projections Commitments and Irreversibility  Cambridge University Press New York NY  2013:1029–136.https://doi.org/10.1017/CBO9781107415324.024W. Kirchstetter, T., Harley, R. A., Kreisberg, N. M., Stolzenburg, M. R., & Hering, S. V. (1999). On-road measurement of fine particle and nitrogen oxide emissions from light- and heavy-duty motor vehicles. Atmospheric Environment, 33(18), 2955-2968. doi:10.1016/s1352-2310(99)00089-8K. BenNaceur L.Cozzi andT.Gould.World Energy Outlook 2016.2016.https://doi.org/10.1787/weo‐2016‐enM.Nesbitet al. Comparative Study on the differences between the EU and US legislation on emissions in the automotive sector.2016.PASTOR, J., JAVIERLOPEZ, J., GARCIA, J., & PASTOR, J. (2008). A 1D model for the description of mixing-controlled inert diesel sprays. Fuel, 87(13-14), 2871-2885. doi:10.1016/j.fuel.2008.04.017PAYRI, R., GARCIA, J., SALVADOR, F., & GIMENO, J. (2005). Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel, 84(5), 551-561. doi:10.1016/j.fuel.2004.10.009Payri, R., Salvador, F. J., Gimeno, J., & Novella, R. (2011). Flow regime effects on non-cavitating injection nozzles over spray behavior. International Journal of Heat and Fluid Flow, 32(1), 273-284. doi:10.1016/j.ijheatfluidflow.2010.10.001Perumal, K., & Ganesan, R. (2015). CFD modeling for the estimation of pressure loss coefficients of pipe fittings: An undergraduate project. Computer Applications in Engineering Education, 24(2), 180-185. doi:10.1002/cae.21695Regueiro, A., Patiño, D., Míguez, C., & Cuevas, M. (2017). A practice for engineering students based on the control and monitoring an experimental biomass combustor using labview. Computer Applications in Engineering Education, 25(3), 392-403. doi:10.1002/cae.21806Sick, V., Drake, M. C., & Fansler, T. D. (2010). High-speed imaging for direct-injection gasoline engine research and development. Experiments in Fluids, 49(4), 937-947. doi:10.1007/s00348-010-0891-3SPALDING, D. B. (1979). The stability of steady exothermic chemical reactions in simple non-adiabatic systems. Combustion and Mass Transfer, 399-406. doi:10.1016/b978-0-08-022106-9.50025-5Weilenmann, M., Soltic, P., Saxer, C., Forss, A.-M., & Heeb, N. (2005). Regulated and nonregulated diesel and gasoline cold start emissions at different temperatures. Atmospheric Environment, 39(13), 2433-2441. doi:10.1016/j.atmosenv.2004.03.081www.upv.es. Universitat Politècnica de València.Zhao, H., & Ladommatos, N. (1998). Optical diagnostics for soot and temperature measurement in diesel engines. Progress in Energy and Combustion Science, 24(3), 221-255. doi:10.1016/s0360-1285(97)00033-

Organizaciones supramoleculares de moléculas dendríticas con estructuras tipo "Bent-Core"

Resumen del póster presentado a la 6ª Jornada de Jóvenes Investigadores en Física y Química de Aragón celebrada en Zaragoza el 20 de noviembre de 2014.Beca de Colaboración del MEC y Beca de Iniciación a la Investigación del INA (A. M. B-S), Beca JAE-Predoc (M. M-A), Beca FPI (A. C.). Grupo de Cristales Líquidos y Polímeros: proyectos MAT2012-38538-CO3-01 y CTQ2012-35692 (MINECO-FEDER) y E04 (Gobierno de Aragón).Peer reviewe

San Pedro Martir observations of microvariability in obscured quasars

Fast brightness variations are a unique tool to probe the innermost regions of active galactic nuclei (AGN). These variations are called microvariability or intra-night variability, and this phenomenon has been monitored in samples of blazars and unobscured AGNs. Detecting optical microvariations in targets hidden by the obscuring torus is a challenging task because the region responsible for the variations is hidden from our sight. However, there have been reports of fast variations in obscured Seyfert galaxies in X-rays, which rises the question whether microvariations can also be detected in obscured AGNs in the optical regime. Because the expected variations are very small and can easily be lost within the noise, the analysis requires a statistical approach. We report the use of a one-way analysis of variance, ANOVA, with which we searched for microvariability. ANOVA was successfully employed in previous studies of unobscured AGNs. As a result, we found microvariable events during three observing blocks: in two we observed the same object (Mrk 477), and in another, J0759+5050. The results on Mrk 477 confirm previous findings. However, since Mrk 477 is quite a peculiar target with hidden broad-line regions, we cannot rule out the possibility that we have serendipitously chosen a target prone to variations.Comment: Research note, 5 pages, 2 figures, accepted for publication in Astronomy and Astrophysic