Laser induced plasma methodology for ignition control in direct injection sprays

New combustion modes for internal combustion engines represent one of the main fields of investigation for emissions control in transportation Industry. However, the implementation of lean fuel mixture condition and low temperature combustion in real engines is limited by different unsolved practical issues. To achieve an appropriate combustion phasing and cycle-to-cycle control of the process, the laser plasma ignition system arises as a valid alternative to the traditional electrical spark ignition system. This paper proposes a methodology to set-up and optimize a laser induced plasma ignition system that allows ensuring reliability through the quantification of the system effectiveness in the plasma generation and positional stability, in order to reach optimal ignition performance. For this purpose, experimental tests have been carried out in an optical test rig. At first the system has been optimized in an atmospheric environment, based on the statistical analysis of the plasma records taken with a high speed camera to evaluate the induction effectiveness and consequently regulate and control the system settings. The same optimization method has then been applied under engine-like conditions, analyzing the effect of thermodynamic ambient conditions on the plasma induction success and repeatability, which have shown to depend mainly on ambient density. Once optimized for selected engine conditions, the laser plasma induction system has been used to ignite a direct injection Diesel spray, and to compare the evolution of combustion with that of a conventional auto-ignited Diesel spray.The authors acknowledge that this research work has been partly funded by the Government of Spain under the project HiReCo TRA2014-58870-R and grant BES-2015-072119. The equipment used in this work has been partially supported by FEDER project ICTS-2012-06, framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Pastor Soriano, JV.; García Oliver, JM.; García Martínez, A.; Pinotti, M. (2016). Laser induced plasma methodology for ignition control in direct injection sprays. Energy Conversion and Management. 120:144-156. https://doi.org/10.1016/j.enconman.2016.04.086S14415612

Comparison of the Diffusive Flame Structure for Dodecane and OMEX Fuels for Conditions of Spray A of the ECN

[EN] A comparison of the flame structure for two different fuels, dodecane and oxymethylene dimethyl ether (OMEX), has been performed under condition of Spray A of the Engine Combustion Network (ECN). The experiments were carried out in a constant pressure vessel with wide optical access, at high pressure and temperature and controlled oxygen concentration. The flame structure analysis has been performed by measuring the formaldehyde and OH radical distributions using planar Laser-Induced Fluorescence (PLIF) techniques. To complement the analysis, this information was combined with that obtained with high-speed imaging of OH* chemiluminescence radiation in the UV. Formaldehyde molecules are excited with the 355-nm radiation from the third harmonic of a Nd:YAG laser, whilst OH is excited with a wavelength of 281.00-nm from a dye laser. In both cases, the beam was transformed into a laser sheet in order to excite an axial flame plane and the fluorescence radiation was collected with an intensified camera (ICCD) and proper filtering. Consequently, two-dimensional maps in the axial flame plane were obtained at different instants after the start of injection (ASOI). Signal from both formaldehyde and OH chemical species can be compared, in order to analyze spatial distribution and interaction. When dodecane and OMEX are compared, several differences arise. The second one presents larger lift-off length but remarkably shorter flame length. Additionally, it has been possible to appreciate for this fuel a lower amount of soot formation during combustion.The research leading to these results has received funding from the European Union's Horizon 2020 Programme, grant agreement n° 828947, and from the Mexican Department of Energy, CONACYT-SENER Hidrocarburos grant agreement n° B-S-69926.Pastor Soriano, JV.; García Oliver, JM.; Micó Reche, C.; Tejada Magraner, FJ. (2020). Comparison of the Diffusive Flame Structure for Dodecane and OMEX Fuels for Conditions of Spray A of the ECN. SAE TECHNICAL PAPERS. https://doi.org/10.4271/2020-01-2120

Schlieren Methodology for the Analysis of Transient Diesel Flame Evolution

[EN] Schlieren/shadowgraphy has been adopted in the combustion research as a standard technique for tip penetration analysis of sprays under diesel-like engine conditions. When dealing with schlieren images of reacting sprays, the combustion process and the subsequent light emission from the soot within the flame have revealed both limitations as well as considerations that deserve further investigation. Seeking for answers to such concerns, the current work reports an experimental study with this imaging technique where, besides spatial filtering at the Fourier plane, both short exposure time and chromatic filtering were performed to improve the resulting schlieren image, as well as the reliability of the subsequent tip penetration measurement. The proposed methodology has reduced uncertainties caused by artificial pixel saturation (blooming). Additionally, an algorithm to calculate Lift-off length from schlieren images has been developed and compared to the more conventional OH* imaging technique. By means of the improved setup, the analysis of transient diesel flame has been performed throughout the ignition and early combustion phases. When compared to a non-reacting vaporizing spray, the temporal evolution of the reacting case departs from the inert one at the start of combustion, when expansion in both axial (i.e. spray tip increase) and radial direction are observed. After that, the tip penetration progressively decreases on a clear transient period where the flow tries to re-organize itself in response to the induced reaction zone. Eventually, the spray undergoes an acceleration period where the reacting spray tip progresses above the non-reacting one. A parametric study has been conducted for three injection pressure levels to investigate the influence of this parameter upon transient flame evolution.This work was partially funded by the Spanish Ministry of Education and Science through the “LES METHODS FOR THE SIMULATION OF MULTIPHASE SPRAYS” project (ENE2010-18542). Mr. Francisco J. Briceño wishes to acknowledge financial support through a PhD studies grant (AP2008-02231) also sponsored by the Spanish Ministry of Education and SciencePastor Soriano, JV.; Payri, R.; García Oliver, JM.; Briceño Sánchez, FJ. (2013). Schlieren Methodology for the Analysis of Transient Diesel Flame Evolution. SAE International Journal of Engines. 6(3):1661-1676. https://doi.org/10.4271/2013-24-0041S166116766

Measurements of OH* and CH* Chemiluminescence in Premixed Flames in a Constant Volume Combustion Bomb under Autoignition Conditions

The objectives of this paper are as follows: (1) To study parametrically OH* and CH* chemiluminescence trace evolution as a function of the initial pressure, temperature, and equivalence ratio of premixed flames of n-heptane, under autoignition conditions, in a constant volume combustion bomb. The signals of the electronically excited states of OH* (306 nm) and CH* (430 nm) have been detected through band-pass filters with two photomultiplier tubes placed in an optical access of the combustion bomb. (2) To determine the feasibility of using OH* and CH* chemiluminescence signals as active-control parameters for premixed flames. For this purpose, a correlation between OH* chemiluminescence emissions and the equivalence ratio and the rate of heat release during the combustion process is obtained, as well as a correlation between CH* chemiluminescence emissions and the adiabatic flame temperature. (3) To investigate the relationship between the OH* and CH* chemiluminescent emissions in premixed combustions of n-heptane, iso-octane, and a mixture of 50% n-heptane and 50% toluene and the equivalence fuel/air ratio for a given initial temperature and pressure. To reach these objectives, measurements of OH* and CH* chemiluminescences from premixed flames of n-heptane with autoignition are reported at equivalence ratios ranging from 0.8 to 1.0, in a constant volume combustion bomb. The morphology of the curves and the relationships with parameters of interest during the combustion process (i.e., the rate of heat release, burned temperature, etc.) are studied. In addition, premixed combustions of iso-octane, n-heptane, and a mixture of n-heptane and toluene are also investigated at different fuel/air equivalence ratios for a given initial pressure and temperature, to assess the possibility of using the ratio between the OH* and CH* chemiluminescence signals to monitorize the equivalence ratio during the combustion, as other authors have considered previously. © 2010 American Chemical Society.The authors of this paper thank the Spanish Ministry of Science and Technology for the financial support of this research through the project TRA2007-67961-C03/AUT and the Regional Government of Castile and Leon through the funding for the GR203 Excellence Research Group. The authors also appreciate the help provided by Dr. Carot for the statistical design of experiments.Tinaut Fluixa, FV.; Reyes, M.; Giménez, B.; Pastor Soriano, JV. (2011). Measurements of OH* and CH* Chemiluminescence in Premixed Flames in a Constant Volume Combustion Bomb under Autoignition Conditions. ENERGY & FUELS. 25:119-129. https://doi.org/10.1021/ef1013456S1191292

An Optical Engine Used as a Physical Model for Studies of the Combustion Process Applying a Two-Color Pyrometry Technique

[EN] This work describes an experimental installation for the investigation of the combustion and injection processes. This installation is based on a two-stroke direct injection diesel engine with a total displacement of 3 L and a cylinder head equipped with three quartz windows. The windows are optical accesses that allow studying the process of injection, the atomization and evaporation of the fuel jet in an inert atmosphere (nitrogen), and the combustion process in a reactive atmosphere (ambient air). Additionally, the application of a two-color pyrometry technique to measure soot formation in this facility is presented. A methodological study is carried out regarding the influence of the dynamic range of the detectors and the wavelengths used. Maps of KL2C, flame temperature, and error probability are presented. The use of cameras with high dynamic range provides better results since the system seems to be less sensitive to measurement noise, and fewer points are obtained with a non-physical solution. Moreover, an appropriate combination of interference filters can improve the reliability of the solution. The greater the difference between the wavelengths of both interference filters, the fewer points with a non-physical solution, which improves the reliability of results.This research was funded by Castilla-La Mancha Government to the project grant number ASUAV Ref. SBPLY/19/180501/000116.Corral-Gómez, L.; Armas, O.; Soriano, JA.; Pastor, JV.; García-Oliver, JM.; Micó, C. (2022). An Optical Engine Used as a Physical Model for Studies of the Combustion Process Applying a Two-Color Pyrometry Technique. Energies. 15(13):1-17. https://doi.org/10.3390/en15134717117151

Evaluación y afrontamiento de los ajetreos diarios : relación con optimismo, perfeccionismo, alexitimia y afecto positivo y negativo

The aim of the present work has been to asses to what extent the contents of the appraisal and the ways of coping with the hassles could be explained on the basis of four personality dimensions: positive and negative affect, optimism, perfectionism and alexithymia. Moreover, it has been tested to what extent the explicit ways of coping are influenced by a specific appraisal or, by contrast, are the personality dimensions the main source of influence. Our results showed that the personality dimensions had a powerful and reliable effect on the appraisal of the events and also on the specific ways of coping. The search for social support basically relies on the personality dimensions but slightly on the contents of the primary and secondary appraisal of the situation. The avoidance is highly influenced by these personality traits and just moderately by the appraisal of the events. Finally, the use of problem solving strategies depends on both types of variables.El propósito del trabajo es comprobar si los contenidos de la evaluación y los modos de afrontamiento que se llevan a cabo ante los ajetreos diarios se pueden explicar a partir de 4 dimensiones de personalidad: afectividad, optimismo, perfeccionismo y alexitimia. Asimismo, se pretende averiguar si los modos concretos de afrontamiento están más influidos por la evaluación concreta que el sujeto realiza sobre la situación, que por estos rasgos de personalidad. Los resultados indican que estas dimensiones, consideradas como factores relativamente estables de la persona, poseen una repercusión clara y poderosa tanto en la valoración que se hace de los acontecimientos, como en la selección de las conductas específicas de afrontamiento. Además, la búsqueda del apoyo social depende sobre todo de estas dimensiones de personalidad y, en mucha menor medida, de los contenidos de evaluación primaria y secundaria de la situación. La evitación está marcadamente condicionada por esas variables de personalidad y sólo de manera moderada por la evaluación. Por último, la utilización de estrategias de solución de problemas, depende por igual de ambos tipos de constructos

A RCCI operational limits assessment in a medium duty compression ignition engine using an adapted compression ratio

Reactivity Controlled Compression Ignition concept offers an ultra-low nitrogen oxide and soot emissions with a high thermal efficiency. This work investigates the capabilities of this low temperature combustion concept to work on the whole map of a medium duty engine proposing strategies to solve its main challenges. In this sense, an extension to high loads of the concept without exceeding mechanical stress as well as a mitigation of carbon oxide and unburned hydrocarbons emissions at low load together with a fuel consumption penalty have been identified as main Reactivity Controlled Compression Ignition drawbacks. For this purpose, a single cylinder engine derived from commercial four cylinders medium-duty engine with an adapted compression ratio of 12.75 is used. Commercial 95 octane gasoline was used as a low reactivity fuel and commercial diesel as a high reactivity fuel. Thus, the study consists of two different parts. Firstly, the work is focused on the development and evaluation of an engine map trying to achieve the maximum possible load without exceeding a pressure rise rate of 15 bar/CAD. The second part holds on improving fuel consumption and carbon oxide and unburned hydrocarbons emissions at low load. Results suggest that it is possible to achieve up to 80% of nominal conventional diesel combustion engine load without overpassing the constraints of pressure rise rate (below 15 bar/CAD) and maximum pressure peak (below 190 bar) while obtaining ultra-low levels of nitrogen oxide and soot emissions. Regarding low load challenges, it has developed a particular methodology sweeping the gasoline-diesel blend together with intake temperature or exhaust gas recirculation maintaining constant the combustion phasing and ultra-low nitrogen oxide and soot emissions. As a result a drastic decrease carbon oxide and unburned hydrocarbons emissions is obtained with a slight fuel consumption improvement.The authors would like to thank VOLVO Group Trucks Technology for supporting this research.Benajes Calvo, JV.; Pastor Soriano, JV.; García Martínez, A.; Boronat-Colomer, V. (2016). A RCCI operational limits assessment in a medium duty compression ignition engine using an adapted compression ratio. Energy Conversion and Management. 126:497-508. doi:10.1016/j.enconman.2016.08.023S49750812

Pain coping strategies and quality of life in patients diagnosed of fibromyalgia

Objetivo: El objetivo de la investigación se centra en el estudio de las estrategias de afrontamiento utilizada por el paciente para hacer frente a su dolor, siendo definidas estas como los pensamientos y acciones que los individuos realizan en sus esfuerzos por manejar el dolor, y su repercusión sobre la calidad de vida del paciente. Material y métodos: La muestra del estudio está formada por 32 mujeres diagnosticadas de fibromialgia que acuden por primera vez al Servicio de Psicología de la Unidad Multidisciplinar del Dolor en el Consorcio Hospital General Universitario de Valencia previa exploración médica. Los pacientes completaron una batería de cuestionarios donde además de recoger las variables sociodemográficas (edad, sexo, estado civil, nivel de estudios), se evaluó el nivel de dolor informado a través del EVA (escala analógica visual), valoración del dolor (por ejemplo, "el dolor depende de mí", "puedo anticipar cuándo me va a doler"...), las estrategias de afrontamiento al dolor a partir del cuestionario de afrontamiento al dolor (CAD) y el cuestionario de calidad de vida ICV-2R. Resultados y conclusiones: A nivel descriptivo, los resultados muestran que las pacientes informan de un nivel de dolor moderadamente elevado, siendo las estrategias de afrontamiento al dolor más utilizadas, la autoafirmación y la búsqueda de información, y presentando un índice de calidad de vida inferior al de la población general. A nivel correlacional, no se ha encontrado ninguna relación significativa entre el índice general de calidad de vida y las estrategias de afrontamiento al dolor, aunque el uso de estrategias de afrontamiento más bien pasivas (como por ejemplo, la religión) se asocian significativa y positivamente con la dimensiones de calidad de vida que implican cierto grado de desadaptación por parte del paciente a la enfermedad, mientras que el uso de estrategias más activas ante el dolor (por ejemplo, distracción y autocontrol mental) se relacionan significativa y negativamente con dichas dimensionesObjective: The objective of this research focused on the study of coping strategies used by patients to face pain, these being defined as the thoughts and actions taken by individuals in their efforts to handle pain and their impact on the patient quality of life. Material and methods: The study population included 32 women diagnosed of fibromyalgia that attended for the first time the Psychology Service of the Multidisciplinary Pain Unit at the Consorcio Hospital General Universitario de Valencia prior medical examination. The patients completed a set of questionnaires that, in addition to obtain sociodemographic variables (age, sex, marital status, educational level), the following was assessed: pain severity determined using a VAS (visual analogic scale), pain valuation (for example, "pain depends on me", "I can anticipate when it is going to hurt"...), pain coping strategies based on the pain coping questionnaire (PCQ) and the quality of life questionnaire ICV-2R. Results and conclusions: At the descriptive level, the results show that the patients reported a moderately severe pain, being self-assertion and information seeking the pain coping strategies more frequently used. Furthermore, they presented a quality of life index lower than the general population. At the correlational level, no significant relationship has been found between the general quality of life index and the pain coping strategies, although the use of more passive coping strategies (such as religion) are significantly and positively associated to dimensions of quality of life that involve certain degree of maladjustment of the patient to the disease, while the use of more active pain coping strategies (such as distraction and mental self-control) are significantly and negatively associated to such dimensions.Psicologí

Prosthetic joint infection by Bordetella holmesii: Case report and a review of the literature

Introduction: Bordetella holmesii is a Gram-negative coccobacillus involved in different infections mostly described in case reports. Prosthetic joint infections in relation to this pathogen are rare. Here, we present the third case of B. holmesii in a patient without anatomical or functional spleen dysfunction. Case report: The patient was a 62-year-old female with a total knee prosthesis implanted in 1997 that required multiple replacements of the femoral component due to aseptic loosening in the past years. The patient was admitted to our hospital for an elective replacement surgery due to new radiological signs of loosening. B. holmesii was isolated from synovial fluid obtained during surgery. The identification was performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and confirmed by 16S rRNA gene amplification and sequencing. Antibiotic treatment was started but 14 days after surgery the patient presented pain and joint effusion. An arthrocentesis was performed and synovial fluid culture was positive again for B. holmesii. Surgical debridement including polyethylene replacement was performed and antibiotic treatment was continued for 3 months. After a 2-year follow-up period, the patient remained asymptomatic and physical examination showed normal function of the prosthesis. Conclusion: B. holmesii is an uncommon cause of bone and joint infections. This case indicates that this microorganism is a potential pathogen of prosthetic or native arthritis, and it should be considered when cultures are negative and in cases presenting torpid evolution

La conducta social en el tráfico: Fundamentos para la intervención.

En este libro nos hemos orientado hacia el estudio de lo “prosocial” frente a lo “antisocial”. Es decir hacia aquellas conductas que favorecen la ayuda entre las personas frente a aquellas que no son de ayuda, que llegan a atentar contra las mismas y por ende contra la sociedad en general. un ámbito de especial interés para nosotros será el del tráfico y la seguridad vial. La prosocialidad esté basada en una decisión interior que requiere, sin lugar a dudas, de un control personal dirigido a un cambio direccional de la naturaleza del ser humano. En este estudio se pretende trabajar el continuo que representa la conducta prosocial y la conducta antisocial y elaborar un análisis de los hallazgos e ideas que, desde la investigación más empírica y experimental, así como desde su interpretación más teórica, nos permita crear un marco conceptual. Sólo el conocimiento del individuo como usuario de la vía y como ser humano, nos permite comprender qué determina su conducta tanto en el tráfico como en otros ámbitos vitales. No obstante, tampoco olvidamos nuestra naturaleza social: el objetivo de nuestro estudio lo constituye el individuo, sí, pero en interacción con otros seres humanos dentro de un determinado espacio social. A lo largo de los diferentes apartados que conforman este libro, realizamos un recorrido por el mundo de la competencia social. Dicho recorrido parte de la descripción y análisis del comportamiento prosocial y lo que hemos considerado su antítesis la conducta antisocial en sus aspectos más generales para llegar a analizar el comportamiento social en el contexto vial Indicaremos que hace falta que nos refiramos al comportamiento prosocial en general, sus interacciones, determinantes, su evaluación… por varias razones. En primer lugar, es imposible entender la conducta prosocial en la conducción sin entender la conducta prosocial en general. En segundo lugar, el comportamiento social en general afecta a la conducción. En efecto, puede ser que el tráfico sea víctima de la prosocialidad o antisocialidad del usuario y que esto tenga su implicación en determinado tipo de accidentes o incidentes, pero no es menos cierto que otros elementos del ámbito generen conductas prosociales en seres que calificamos de “antisociales”, y ¿por qué no? conductas antisociales en los seres más prosociales. Porque, “no hay nadie radicalmente bueno ni malo”. Por último, es necesario realizar un ejercicio de inferencia si queremos dibujar un panorama más o menos completo sobre esta cuestión. Comenzaremos definiendo qué es una conducta prosocial y su relación con conductas y valores como la solidaridad y el altruismo. Posteriormente, vamos a relacionar y describir los determinantes de la conducta prosocial desde el punto de vista biológico, socio-cultural, del aprendizaje y cognitivo. También abordaremos específicamente la participación de la personalidad del sujeto a la hora de ser y comportarse de forma prosocial o antisocial. Trataremos por último algunas perspectivas teóricas y abordaremos la conducta antisocial como opuesta a la prosocialidad. A partir de este momento es cuando nos centraremos en la conducta social en el contexto vial. Recogeremos algunas de las cuestiones que anteriormente tratamos en general y lo particularizaremos en este ámbito y plantearemos la intervención de la competencia social en el tráfico. Para ello hablaremos de las habilidades necesarias para la conducción, la prevención y la rehabilitación de la conducta antisocial y de lo que desde nuestro punto de vista es eje de la prevención, “el desarrollo social”, es decir, el fomento de la empatía y la prosocialidad Para finalizar, se describirán algunas conclusiones donde se recogen las cuestiones citadas anteriormente desde una perspectiva si cabe más práctica, aplicada y sencilla