Light signaling: back to space

Recent work has increased our understanding of the molecular and cellular mechanisms of the phytochrome family of photoreceptors in controlling plant photomorphogenesis. However, the importance of long-distance communication in controlling light responses has received relatively little attention and is poorly understoodPostprint (author's final draft

La creación de un modelo de análisis de la información visual, sonora y háptica en un videojuego para la mejora de accesibilidad a personas con discapacidad visual

People with visual impairment are one of the groups with more difficulties to enjoy the audiovisual products, even more in the case of video games. Universal accessibility tries to take down those barriers and to reach that goal it needs to find alternative procedures to the visual channel in order to communicate the same information and interaction. A model to analyze the information communicated in their different levels and screens, through the visual, sound and haptic channels, will help to identify the information that is just communicated through pictures, with subsequent possible applications to the accessibility of that game

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

[EN] Growing interest has arisen to adopt Variable Valve Timing (VVT) technology for automotive engines due to the need to fulfill the pollutant emission regulations. Several VVT strategies, such as the exhaust re-opening and the late exhaust closing, can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to simulate several VVT strategies and develop a control system to actuate over the valves timing in order to increase diesel oxidation catalyst efficiency and reduce the exhaust pollutant emissions. A transient operating conditions comparison, taking the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC) as a reference, has been done by analyzing fuel economy, HC and CO pollutant emissions levels. The results conclude that the combination of an early exhaust and a late intake valve events leads to a 20% reduction in CO emissions with a fuel penalty of 6% over the low speed stage of the WLTC, during the warm-up of the oxidation catalyst. The same set-up is able to reduce HC emissions down to 16% and NO(x)emission by 13%.This research has been partially funded by the Spanish government under the grant agreement TRA2017-89894-R ("Mecoem"). Angel Aunon was supported through the "Apoyo para la investigacion y Desarrollo (PAID)" grant for doctoral studies (FPI S2 2018 1048) by Universitat Politecnica de Valencia.Serrano, J.; Arnau Martínez, FJ.; Martín, J.; Auñón-García, Á. (2020). Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine. Energies. 13(17):1-26. https://doi.org/10.3390/en13174561S1261317Arnau, F. J., Martín, J., Pla, B., & Auñón, Á. (2020). Diesel engine optimization and exhaust thermal management by means of variable valve train strategies. International Journal of Engine Research, 22(4), 1196-1213. doi:10.1177/1468087419894804Luján, J. M., Serrano, J. R., Piqueras, P., & García-Afonso, Ó. (2015). Experimental assessment of a pre-turbo aftertreatment configuration in a single stage turbocharged diesel engine. Part 2: Transient operation. Energy, 80, 614-627. doi:10.1016/j.energy.2014.12.017Lancefield, T., Methley, I., Räse, U., & Kuhn, T. (2000). The Application of Variable Event Valve Timing to a Modern Diesel Engine. SAE Technical Paper Series. doi:10.4271/2000-01-1229Gonzalez D, M. A., & Di Nunno, D. (2016). Internal Exhaust Gas Recirculation for Efficiency and Emissions in a 4-Cylinder Diesel Engine. SAE Technical Paper Series. doi:10.4271/2016-01-2184Serrano, J. R., Piqueras, P., Navarro, R., Gómez, J., Michel, M., & Thomas, B. (2016). Modelling Analysis of Aftertreatment Inlet Temperature Dependence on Exhaust Valve and Ports Design Parameters. SAE Technical Paper Series. doi:10.4271/2016-01-0670Siewert, R. M. (1971). How Individual Valve Timing Events Affect Exhaust Emissions. SAE Technical Paper Series. doi:10.4271/710609Tomoda, T., Ogawa, T., Ohki, H., Kogo, T., Nakatani, K., & Hashimoto, E. (2010). Improvement of Diesel Engine Performance by Variable Valve Train System. International Journal of Engine Research, 11(5), 331-344. doi:10.1243/14680874jer586Benajes, J., Reyes, E., & Luján, J. M. (1996). Modelling Study of the Scavenging Process in a Turbocharged Diesel Engine with Modified Valve Operation. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 210(4), 383-393. doi:10.1243/pime_proc_1996_210_210_02Deppenkemper, K., Özyalcin, C., Ehrly, M., Schoenen, M., Bergmann, D., & Pischinger, S. (2018). 1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications. SAE Technical Paper Series. doi:10.4271/2018-01-0163Zammit, J. P., McGhee, M. J., Shayler, P. J., Law, T., & Pegg, I. (2015). The effects of early inlet valve closing and cylinder disablement on fuel economy and emissions of a direct injection diesel engine. Energy, 79, 100-110. doi:10.1016/j.energy.2014.10.065Pan, X., Zhao, Y., Lou, D., & Fang, L. (2020). Study of the Miller Cycle on a Turbocharged DI Gasoline Engine Regarding Fuel Economy Improvement at Part Load. Energies, 13(6), 1500. doi:10.3390/en13061500Guan, W., Pedrozo, V. B., Zhao, H., Ban, Z., & Lin, T. (2019). Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine. International Journal of Engine Research, 21(4), 578-591. doi:10.1177/1468087419846031Guan, W., Zhao, H., Ban, Z., & Lin, T. (2018). Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine. International Journal of Engine Research, 20(4), 381-392. doi:10.1177/1468087418755586Maniatis, P., Wagner, U., & Koch, T. (2018). A model-based and experimental approach for the determination of suitable variable valve timings for cold start in partial load operation of a passenger car single-cylinder diesel engine. International Journal of Engine Research, 20(1), 141-154. doi:10.1177/1468087418817119Kim, J., & Bae, C. (2015). An investigation on the effects of late intake valve closing and exhaust gas recirculation in a single-cylinder research diesel engine in the low-load condition. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 230(6), 771-787. doi:10.1177/0954407015595149Zhou, X., Liu, E., Sun, D., & Su, W. (2018). Study on transient emission spikes reduction of a heavy-duty diesel engine equipped with a variable intake valve closing timing mechanism and a two-stage turbocharger. International Journal of Engine Research, 20(3), 277-291. doi:10.1177/1468087417748837Gosala, D. B., Ramesh, A. K., Allen, C. M., Joshi, M. C., Taylor, A. H., Van Voorhis, M., … Stretch, D. (2017). Diesel engine aftertreatment warm-up through early exhaust valve opening and internal exhaust gas recirculation during idle operation. International Journal of Engine Research, 19(7), 758-773. doi:10.1177/1468087417730240Parvate-Patil, G. B., Hong, H., & Gordon, B. (2004). Analysis of Variable Valve Timing Events and Their Effects on Single Cylinder Diesel Engine. SAE Technical Paper Series. doi:10.4271/2004-01-2965Piano, A., Millo, F., Di Nunno, D., & Gallone, A. (2017). Numerical Analysis on the Potential of Different Variable Valve Actuation Strategies on a Light Duty Diesel Engine for Improving Exhaust System Warm Up. SAE Technical Paper Series. doi:10.4271/2017-24-0024Payri, F., Arnau, F. J., Piqueras, P., & Ruiz, M. J. (2018). Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications. SAE Technical Paper Series. doi:10.4271/2018-01-0954Martin, J., Arnau, F., Piqueras, P., & Auñon, A. (2018). Development of an Integrated Virtual Engine Model to Simulate New Standard Testing Cycles. SAE Technical Paper Series. doi:10.4271/2018-01-1413Serrano, J. R., Arnau, F. J., García-Cuevas, L. M., Dombrovsky, A., & Tartoussi, H. (2016). Development and validation of a radial turbine efficiency and mass flow model at design and off-design conditions. Energy Conversion and Management, 128, 281-293. doi:10.1016/j.enconman.2016.09.032Galindo, J., Tiseira, A., Navarro, R., Tarí, D., Tartoussi, H., & Guilain, S. (2016). Compressor Efficiency Extrapolation for 0D-1D Engine Simulations. SAE Technical Paper Series. doi:10.4271/2016-01-0554Serrano, J. R., Olmeda, P., Arnau, F. J., & Samala, V. (2019). A holistic methodology to correct heat transfer and bearing friction losses from hot turbocharger maps in order to obtain adiabatic efficiency of the turbomachinery. International Journal of Engine Research, 21(8), 1314-1335. doi:10.1177/1468087419834194Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2014). Analysis and Methodology to Characterize Heat Transfer Phenomena in Automotive Turbochargers. Journal of Engineering for Gas Turbines and Power, 137(2). doi:10.1115/1.4028261Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2015). Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes. Energy, 86, 204-218. doi:10.1016/j.energy.2015.03.130Arrègle, J., López, J. J., Martín, J., & Mocholí, E. M. (2006). Development of a Mixing and Combustion Zero-Dimensional Model for Diesel Engines. SAE Technical Paper Series. doi:10.4271/2006-01-1382Payri, F., Arrègle, J., López, J. J., & Mocholí, E. (2008). Diesel NOx Modeling with a Reduction Mechanism for the Initial NOx Coming from EGR or Re-entrained Burned Gases. SAE Technical Paper Series. doi:10.4271/2008-01-1188Broatch, A., Olmeda, P., Martin, J., & Salvador-Iborra, J. (2018). Development and Validation of a Submodel for Thermal Exchanges in the Hydraulic Circuits of a Global Engine Model. SAE Technical Paper Series. doi:10.4271/2018-01-0160Guardiola, C., Pla, B., Bares, P., & Mora, J. (2018). An on-board method to estimate the light-off temperature of diesel oxidation catalysts. International Journal of Engine Research, 21(8), 1480-1492. doi:10.1177/1468087418817965Russell, A., & Epling, W. S. (2011). Diesel Oxidation Catalysts. Catalysis Reviews, 53(4), 337-423. doi:10.1080/01614940.2011.596429Guardiola, C., Pla, B., Piqueras, P., Mora, J., & Lefebvre, D. (2017). Model-based passive and active diagnostics strategies for diesel oxidation catalysts. Applied Thermal Engineering, 110, 962-971. doi:10.1016/j.applthermaleng.2016.08.207Abdelghaffar, W. A., Osman, M. M., Saeed, M. N., & Abdelfatteh, A. I. (2002). Effects of Coolant Temperature on the Performance and Emissions of a Diesel Engine. Design, Operation, and Application of Modern Internal Combustion Engines and Associated Systems. doi:10.1115/ices2002-464Torregrosa, A. J., Olmeda, P., Martín, J., & Degraeuwe, B. (2006). Experiments on the influence of inlet charge and coolant temperature on performance and emissions of a DI Diesel engine. Experimental Thermal and Fluid Science, 30(7), 633-641. doi:10.1016/j.expthermflusci.2006.01.00

A complete 0D thermodynamic predictive model for direct injection diesel engines

[EN] Ideal models provide the simplest way to reproduce internal combustion engine (ICE) cycles, but they usually do not represent with sufficient accuracy the actual behaviour of an ICE. A suitable alternative for research and development applications is provided by zero-dimensional (0D) thermodynamic models. Such models are very useful for predicting the instantaneous pressure and temperature in the combustion chamber, which in turn allows the prediction of engine operation characteristics. However, they use simplifying hypotheses which lead, in some cases, to a lack of accuracy or a limited predictive capability.This paper describes a 0D single-zone thermodynamic model that takes into account the heat transfer to the chamber walls, the blow-by leakage, the fuel injection and engine deformations, along with the instantaneous change in gas properties. Special attention has been paid to the description of the specific sub-models that have been used for the calculation of the energy and mass equations terms. The procedures followed for the estimation of some mechanical and heat transfer parameters and the combustion model fitting are also detailed. After the fitting, the model was validated in different operation points in a 4-cylinder 2-l DI diesel engine, showing a good capability for accurate predictions of engine performance and the gas state in the closed cycle. © 2011 Elsevier Ltd.The authors thank the Universitat Politecnica de Valencia (PAID-06-09) and Generalitat Valenciana (GV/2010/045) for their valuable support to this work and the referees for their worthy comments.Payri González, F.; Olmeda, P.; Martín Díaz, J.; García Martínez, A. (2011). A complete 0D thermodynamic predictive model for direct injection diesel engines. Applied Energy. 88:4632-4641. doi:10.1016/j.apenergy.2011.06.005S463246418

Diesel engine optimization and exhaust thermal management by means of variable valve train strategies

[EN] Due to the need to achieve a fast warm-up of the after-treatment system in order to fulfill the pollutant emission regulations, a growing interest has arisen to adopt variable valve timing technology for automotive engines. Several variable valve timing strategies can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to carry out a simulation study comparing several exhaust variable valve actuation strategies. A steady-state analysis has been done in order to evaluate the potential of the different strategies at different operating points. Finally, the effect on the after-treatment warm-up, fuel economy and pollutant emission levels was evaluated over the worldwide harmonized light vehicles test cycle. As a conclusion, the combination of an advanced exhaust (early exhaust valve opening and early exhaust valve closing) and a delayed intake (late intake valve opening and late intake valve closing) presented the best trade-off between exhaust temperature increment and fuel consumption, which achieved a mean temperature increment during low-speed phase of the worldwide harmonized light vehicles test cycle of 27¿°C with a fuel penalty of 6%. The exhaust valve re-opening technique offers a worse trade-off. However, the exhaust valve re-opening leads to lower nitrogen oxide (29% less) and carbon monoxide (11% less) pollutant emissions.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research has been partially funded by the European Union's Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 ("DiePeR") and by the Spanish government under the grant agreement TRA2017-89894-R. The authors want to acknowledge the "Apoyo para la investigacion y Desarrollo (PAID)," grant for doctoral studies (FPI S2 2018 1048), of Universitat Politecnica de Valencia.Arnau Martínez, FJ.; Martín, J.; Pla Moreno, B.; Auñón-García, Á. (2021). Diesel engine optimization and exhaust thermal management by means of variable valve train strategies. International Journal of Engine Research. 22(4):1196-1213. https://doi.org/10.1177/1468087419894804S1196121322

Development of an Integrated Virtual Engine Model to Simulate New Standard Testing Cycles

[EN] The combination of more strict regulation for pollutant and CO2 emissions and the new testing cycles, covering a wider range of transient conditions, makes very interesting the development of predictive tools for engine design and pre-calibration. This paper describes a new integrated Virtual Engine Model (VEMOD) that has been developed as a standalone tool to simulate new standard testing cycles. The VEMOD is based on a wave-action model that carries out the thermo-and fluid dynamics calculation of the gas in each part of the engine. In the model, the engine is represented by means of 1D ducts, while the volumes, such as cylinders and reservoirs, are considered as 0D elements. Different sub-models are included in the VEMOD to take into account all the relevant phenomena. Thus, the combustion process is calculated by the Apparent Combustion Time (ACT) 1D model, responsible for the prediction of the rate of heat release and NOx formation. Experimental correlations are used to determine the rest of pollutants. In order to predict tailpipe pollutant emissions to the ambient, different sub-models have been developed to reproduce the behavior of the aftertreatment devices (DOC and DPF) placed in the exhaust system. Dedicated friction and auxiliaries sub-models allow obtaining the brake power. The turbocharger consists of 0D compressor and turbine sub-models capable of extrapolating the available maps of both devices. The VEMOD includes coolant and lubricant circuits linked, on the one hand, with the engine block and the turbocharger through heat transfer lumped models; and on the other hand with the engine heat exchangers. A control system emulating the ECU along with vehicle and driver sub-models allow completing the engine simulation. The Virtual Engine Model has been validated with experimental tests in a 1.6 L Diesel engine using steady and transient tests in both hot and cold conditions. Engine torque was predicted with a mean error of 3 Nm and an error below 14 Nm for 90 % of the cycle duration. CO2 presented a mean error of 0.04 g/s, while during 80 % of the cycle, error was below 0.44 g/s.This research has been partially funded by the European Union’s Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 (“DiePeR”) and by the Spanish government under the grant agreement TRA2017-89894-R. The authors wish to thank Renault SAS, especially P. Mallet and E. Gaïffas, for supporting this research.Martín Díaz, J.; Arnau Martínez, FJ.; Piqueras, P.; Auñón-García, Á. (2018). Development of an Integrated Virtual Engine Model to Simulate New Standard Testing Cycles. SAE Technical Papers. https://doi.org/10.4271/2018-01-1413

A bone remodelling model including the effect of damage on the steering of BMUs

Bone remodelling in cortical bone is performed by the so-called basic multicellular units (BMUs), which produce osteons after completing the remodelling sequence. Burger et al. (2003) hypothesized that BMUs follow the direction of the prevalent local stress in the bone. More recently, Martin (2007) has shown that BMUs must be somehow guided by microstructural damage as well. The interaction of both variables, strain and damage, in the guidance of BMUs has been incorporated into a bone remodelling model for cortical bone. This model accounts for variations in porosity, anisotropy and damage level. The bone remodelling model has been applied to a finite element model of the diaphysis of a human femur. The trajectories of the BMUs have been analysed throughout the diaphysis and compared with the orientation of osteons measured experimentally. Some interesting observations, like the typical fan arrangement of osteons near the periosteum, can be explained with the proposed remodelling model. Moreover, the efficiency of BMUs in damage repairing has been shown to be greater if BMUs are guided by damage

Comparison of the volumetric composition of lamellar bone and the woven bone of calluses

Woven tissue is mainly present in the bone callus, formed very rapidly either after a fracture or in distraction processes. This high formation speed is probably responsible for its disorganized microstructure and this, in turn, for its low stiffness. Nonetheless, the singular volumetric composition of this tissue may also play a key role in its mechanical properties. The volumetric composition of woven tissue extracted from the bone transport callus of sheep was investigated and compared with that of the lamellar tissue extracted from the cortical shell of the same bone. Significant differences were found in the mineral and water contents, but they can be due to the different ages of both tissues, which affects the mineral/water ratio. However, the content in organic phase remains more or less constant throughout the mineralization process and has proven to be a good variable to measure the different composition of both tissues, being that content significantly higher in woven tissue. This may be linked to the abnormally high concentration of osteocytes in this tissue, which is likely a consequence of the more abundant presence of osteoblasts secreting osteoid and burying other osteoblasts, which then differentiate into osteocytes. This would explain the high formation rate of woven tissue, useful to recover the short-term stability of the bone. Nonetheless, the more abundant presence of organic phase prevents the woven tissue from reaching a stiffness similar to that of lamellar tissue in the long term, when it is fully mineralized

Wireless measurement system for structural health monitoring with high time synchronization accuracy

Structural health monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of structures. Wireless networks (WNs) have been used to avoid the high cost of traditional generic wired systems. The most important limitation of SHM wireless systems is time-synchronization accuracy, scalability, and reliability. A complete wireless system for structural identification under environmental load is designed, implemented, deployed, and tested on three different real bridges. Our contribution ranges from the hardware to the graphical front end. System goal is to avoid the main limitations of WNs for SHM particularly in regard to reliability, scalability, and synchronization. We reduce spatial jitter to 125 ns, far below the 120 μs required for high-precision acquisition systems and much better than the 10-μs current solutions, without adding complexity. The system is scalable to a large number of nodes to allow for dense sensor coverage of real-world structures, only limited by a compromise between measurement length and mandatory time to obtain the final result. The system addresses a myriad of problems encountered in a real deployment under difficult conditions, rather than a simulation or laboratory test bed