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In the current work, the combustion process inside a stratified pre-chamber ignition system is analyzed. The pre-chamber is installed on a Rapid Compression-Expansion Machine (RCEM) and runs at different combinations of fuel-air equivalence ratio in the main chamber as well as in the pre-chamber, which is controlled by a fuel injection during the compression stroke. In order to analyze the results in detail, a zero-dimensional model for the pre-chamber is proposed. First, a K-k-ϵ model is developed and calibrated according to three-dimensional simulations in motoring conditions performed in a Computational Fluid Dynamic solver (Converge). Then, a thermodynamic model including the mass exchange between both chambers as wells as the heat transfer losses to the walls is used to compute the instantaneous heat release rate in the pre-chamber. Both pieces of information are combined to evaluate the effective flame propagation speed, and also to decouple the effects in terms of laminar flame speed, turbulence-flame interaction and gas velocity due to expansion effects in the burned products. The flame speed values obtained are consistent when the equivalence ratio in the pre-chamber is maintained, regardless the conditions in the main chamber, while a significant deterioration is seen once lean operation appears in the pre-chamber. Finally, the flame speed is compared to an average propagation speed estimated from broadband chemiluminescence visualization tests, showing good consistency with the model predictions.
V. Macián; F.J. Salvador; J. De la Morena; V. Pagano. Combustion analysis of a stratified pre-chamber ignition system by means of a zero-dimensional turbulence and flame speed model. Combustion and Flame 2021, 232, 111526 .
AMA StyleV. Macián, F.J. Salvador, J. De la Morena, V. Pagano. Combustion analysis of a stratified pre-chamber ignition system by means of a zero-dimensional turbulence and flame speed model. Combustion and Flame. 2021; 232 ():111526.
Chicago/Turabian StyleV. Macián; F.J. Salvador; J. De la Morena; V. Pagano. 2021. "Combustion analysis of a stratified pre-chamber ignition system by means of a zero-dimensional turbulence and flame speed model." Combustion and Flame 232, no. : 111526.
In the current paper, a methodology combining a case study with a computational tool for aerospace engineering students is presented and discussed. The aim of this methodology is to improve the understanding of jet engine's operation through their thermodynamic cycle analysis, particularly focused on the effects of the main boundary conditions for an aircraft engine: altitude and flight velocity (or Mach). Additionally, the organization of the methodology as a case study performed in groups helps to facilitate student engagement, as well as the development of soft skills, such as teamwork ability. The experience of this methodology over the last 5 years shows that the activity is generally well perceived by the students, and also that there is a correlation between the engagement in this activity and the overall results achieved in the subject, confirming that the methodology helps to improve students' comprehension of the concepts behind engine performance. However, a few points of improvement for the near future are identified.
Pedro Piqueras; Joaquín De la Morena; Pau Bares; Enrique J. Sanchis. Case study‐based learning using a computational tool to improve the understanding of the jet engine cycle for aerospace engineering degree students. Computer Applications in Engineering Education 2021, 1 .
AMA StylePedro Piqueras, Joaquín De la Morena, Pau Bares, Enrique J. Sanchis. Case study‐based learning using a computational tool to improve the understanding of the jet engine cycle for aerospace engineering degree students. Computer Applications in Engineering Education. 2021; ():1.
Chicago/Turabian StylePedro Piqueras; Joaquín De la Morena; Pau Bares; Enrique J. Sanchis. 2021. "Case study‐based learning using a computational tool to improve the understanding of the jet engine cycle for aerospace engineering degree students." Computer Applications in Engineering Education , no. : 1.
The earlier activation of the catalytic converters in internal combustion engines is becoming highly challenging due to the reduction in exhaust gas temperature caused by the application of CO2 reduction technologies. In this context, the use of pre-turbine catalysts arises as a potential way to increase the conversion efficiency of the exhaust aftertreatment system. In this work, a small-sized oxidation catalyst consisting of a honeycomb thin-wall metallic substrate was placed upstream of the turbine to benefit from the higher temperature and pressure prior to the turbine expansion. The change in engine performance and emissions in comparison to the baseline configuration are analyzed under driving conditions. As an individual element, the pre-turbine catalyst contributed positively with a relevant increase in the overall CO and HC conversion efficiency. However, its placement produced secondary effects on the engine and baseline aftertreatment response. Although small-sized monoliths are advantageous to minimize the thermal inertia impact on the turbocharger lag, the catalyst cross-section is in trade-off with the additional pressure drop that the monolith causes. As a result, the higher exhaust manifold pressure in pre-turbine pre-catalyst configuration caused a fuel consumption increase higher than 3% while the engine-out CO and HC emissions did around 50%. These increments were not completely offset despite the high pre-turbine pre-catalyst conversion efficiency (>40%) because the partial abatement of the emissions in this device conditioned the performance of the close-coupled oxidation catalyst.
José Serrano; Pedro Piqueras; Joaquín Morena; María Ruiz. Influence of Pre-Turbine Small-Sized Oxidation Catalyst on Engine Performance and Emissions under Driving Conditions. Applied Sciences 2020, 10, 7714 .
AMA StyleJosé Serrano, Pedro Piqueras, Joaquín Morena, María Ruiz. Influence of Pre-Turbine Small-Sized Oxidation Catalyst on Engine Performance and Emissions under Driving Conditions. Applied Sciences. 2020; 10 (21):7714.
Chicago/Turabian StyleJosé Serrano; Pedro Piqueras; Joaquín Morena; María Ruiz. 2020. "Influence of Pre-Turbine Small-Sized Oxidation Catalyst on Engine Performance and Emissions under Driving Conditions." Applied Sciences 10, no. 21: 7714.
Exhaust gas recirculation is one of the technologies that can be used to improve the efficiency of spark-ignition engines. However, apart from fuel consumption reduction, this technology has a significant impact on exhaust gaseous emissions, inducing a significant reduction in nitrogen oxides and an increase in unburned hydrocarbons and carbon monoxide, which can affect operation of the aftertreatment system. In order to evaluate these effects, data extracted from design of experiments done on a multi-cylinder 1.3 L turbocharged spark-ignition engine with variable valve timing and low-pressure exhaust gas recirculation (EGR) are used. The test campaign covers the area of interest for the engine to be used in new-generation hybrid electric platforms. In general, external EGR provides an approximately linear decrease of nitrogen oxides and deterioration of unburned hydrocarbon emissions due to thermal and flame quenching effects. At low load, the impact on emissions is directly linked to actuation of the variable valve timing system due to the interaction of EGR with internal residuals. For the same external EGR rate, running with high valve overlap increases the amount of internal residuals trapped inside the cylinder, slowing down combustion and increasing Unburnt hydrocarbon (HC) emissions. However, low valve overlap (i.e., low internal residuals) operation implies a decrease in oxygen concentration in the exhaust line for the same air–fuel ratio inside the cylinders. At high load, interaction with the variable valve timing system is reduced, and general trends of HC increase and of oxygen and carbon monoxide decrease appear as EGR is introduced. Finally, a simple stoichiometric model evaluates the potential performance of a catalyst targeted for EGR operation. The results highlight that the decrease of nitrogen oxides and oxygen availability together with the increase of unburned hydrocarbons results in a huge reduction of the margin in oxygen availability to achieve a complete oxidation from a theoretical perspective. This implies the need to rely on the oxygen storage capability of the catalyst or the possibility to control at slightly lean conditions, taking advantage of the nitrogen oxide reduction at engine-out with EGR.
Pedro Piqueras; Joaquín De La Morena; Enrique José Sanchis; Rafael Pitarch. Impact of Exhaust Gas Recirculation on Gaseous Emissions of Turbocharged Spark-Ignition Engines. Applied Sciences 2020, 10, 7634 .
AMA StylePedro Piqueras, Joaquín De La Morena, Enrique José Sanchis, Rafael Pitarch. Impact of Exhaust Gas Recirculation on Gaseous Emissions of Turbocharged Spark-Ignition Engines. Applied Sciences. 2020; 10 (21):7634.
Chicago/Turabian StylePedro Piqueras; Joaquín De La Morena; Enrique José Sanchis; Rafael Pitarch. 2020. "Impact of Exhaust Gas Recirculation on Gaseous Emissions of Turbocharged Spark-Ignition Engines." Applied Sciences 10, no. 21: 7634.
New generation of spark ignition (SI) engines are expected to represent most of the future market share in a context of powertrain hybridization. Nevertheless, the current technology has still critical challenges in front to meet incoming CO2 and pollutant emissions standards, so new technologies are emerging to improve engine efficiency. In parallel to combustion concepts, a key required trend is downsizing based on high engine boosting. New turbocharger technologies, such as variable geometry turbines (VGT), become suitable for its application under the demanding operating conditions of SI engines. In this work, a methodology for the analysis of the VGT usage in comparison with traditional waste-gate (WG) turbine is presented. From experimental data obtained in engine test cell, a theoretical analysis aimed at ensuring full control on turbine boundary conditions, such as combustion variability, compressor map or engine calibration, was conducted. Taking advantage of highly validated and physically representative 1-D gas-dynamics and turbocharger models, the engine performance is discussed as a function of the turbine technology at full and partial load in a wide range of engine speed at the same time as the altitude impact is addressed. In all, it was found that VGT technology shows less limitations in extreme working conditions, such as low- and high-end torque regions, where the WG technology represents a limitation in terms of the maximum power output. Full load differences become more even more evident in altitude working conditions. When it comes to partial loads, differences in fuel consumption are minor, but potentially beneficial for VGTs.
José Ramón Serrano; Pedro Piqueras; Joaquín De la Morena; Alejandro Gómez-Vilanova; Stéphane Guilain. Methodological analysis of variable geometry turbine technology impact on the performance of highly downsized spark-ignition engines. Energy 2020, 215, 119122 .
AMA StyleJosé Ramón Serrano, Pedro Piqueras, Joaquín De la Morena, Alejandro Gómez-Vilanova, Stéphane Guilain. Methodological analysis of variable geometry turbine technology impact on the performance of highly downsized spark-ignition engines. Energy. 2020; 215 ():119122.
Chicago/Turabian StyleJosé Ramón Serrano; Pedro Piqueras; Joaquín De la Morena; Alejandro Gómez-Vilanova; Stéphane Guilain. 2020. "Methodological analysis of variable geometry turbine technology impact on the performance of highly downsized spark-ignition engines." Energy 215, no. : 119122.
The present work analyses the effect of the eccentricity of diesel nozzle orifices over the spray behaviour by means of CFD simulations. Several orifice geometries with varying horizontal eccentricity (from 0.50 to 0.94) are selected. Their performance is assessed at a high injection pressure of 200 MPa, a 3 MPa back-pressure and non-evaporative conditions. The nozzle flow characteristics, including cavitation modelled by a Homogeneous Relaxation Model (HRM), are accounted for in the spray performance by means of a Σ - Y model. The code is validated via two reference nozzles, the so called ”Spray A” of the Engine Combustion Network plus a second nozzle from a production injector, and then extended to the eccentric geometries. The results and discussions include spray angle and penetration, air entrainment and flow parameters of the nozzle inner conditions versus the eccentricity value.
F.J. Salvador; J.M. Pastor; J. De la Morena; E.C. Martínez-Miracle. Computational study on the influence of nozzle eccentricity in spray formation by means of Eulerian Σ - Y coupled simulations in diesel injection nozzles. International Journal of Multiphase Flow 2020, 129, 103338 .
AMA StyleF.J. Salvador, J.M. Pastor, J. De la Morena, E.C. Martínez-Miracle. Computational study on the influence of nozzle eccentricity in spray formation by means of Eulerian Σ - Y coupled simulations in diesel injection nozzles. International Journal of Multiphase Flow. 2020; 129 ():103338.
Chicago/Turabian StyleF.J. Salvador; J.M. Pastor; J. De la Morena; E.C. Martínez-Miracle. 2020. "Computational study on the influence of nozzle eccentricity in spray formation by means of Eulerian Σ - Y coupled simulations in diesel injection nozzles." International Journal of Multiphase Flow 129, no. : 103338.
Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.
José Ramón Serrano; Pedro Piqueras; Joaquín De La Morena; Enrique José Sanchis. Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration. Applied Sciences 2019, 9, 5384 .
AMA StyleJosé Ramón Serrano, Pedro Piqueras, Joaquín De La Morena, Enrique José Sanchis. Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration. Applied Sciences. 2019; 9 (24):5384.
Chicago/Turabian StyleJosé Ramón Serrano; Pedro Piqueras; Joaquín De La Morena; Enrique José Sanchis. 2019. "Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration." Applied Sciences 9, no. 24: 5384.
A control-oriented model of spark ignition combustion is presented. The model makes use of avaliable signals, such as spark advance, air mass, intake pressure, and lambda, to characterize not only the average combustion evolution but also the cycle-to-cycle variability. The conventional turbulent flame propagation model with two states, namely entrained mass and burnt mass, is improved by look-up tables at some parameters, and the cycle-to-cycle variability is estimated by propagation of an exogenous noise with a normal probabilistic distribution at the turbulent and laminar flame speed, which intends to simulate the unknowns at turbulent flow, temperature distribution, or initial kernel distribution. The model is able to estimate which is the expected variability during the combustion evolution and might be used online for characterizing the time response of closed-loop control actions or it can be used offline to improve the control strategies without large experimental test campaigns. Experimental data from a four-stroke commercial engine was used for calibration and validation purposes, demonstrating the capabilities of the model in steady and transient conditions.
Benjamin Pla; Joaquin De La Morena; Pau Bares; Irina Ayelén Jiménez. Cycle-to-cycle combustion variability modelling in spark ignited engines for control purposes. International Journal of Engine Research 2019, 21, 1398 -1411.
AMA StyleBenjamin Pla, Joaquin De La Morena, Pau Bares, Irina Ayelén Jiménez. Cycle-to-cycle combustion variability modelling in spark ignited engines for control purposes. International Journal of Engine Research. 2019; 21 (8):1398-1411.
Chicago/Turabian StyleBenjamin Pla; Joaquin De La Morena; Pau Bares; Irina Ayelén Jiménez. 2019. "Cycle-to-cycle combustion variability modelling in spark ignited engines for control purposes." International Journal of Engine Research 21, no. 8: 1398-1411.
An investigation of the interaction between the in-cylinder flow and the spray topology in two spray-guided direct injection optical engines is reported. The bulk flow field in the combustion chamber is characterized using particle image velocimetry. Geometrical parameters such as the axial penetration and the spray angle of the liquid spray are measured using Mie scatter imaging and/or diffuse back-illumination. The measured parameters are compared with data from a constant volume chamber available in the literature. For a late injection strategy, the so-called ECN Spray G standard condition, the mean values of the spray penetration do not seem to be significantly perturbed by the in-cylinder flow motion until the plumes approach the piston surface. However, spray probability maps reveal that cycle-to-cycle fluctuations of the spatial distribution of the liquid spray are affected by the magnitude of the in-cylinder flow. Particle image velocimetry during injection shows that the flow field in the vicinity of the spray plumes is heavily influenced by air entrainment, and that an upward flow in-between spray plumes develops. Consistent with previous research that demonstrated the importance of the latter flow structure for the prevention of spray collapse, it is found that increased in-cylinder flow magnitudes due to increased intake valve lifts or engine speeds enhance the spray-shape stability. Compared with cases without injection, the influence of the spray on the in-cylinder flow field is still noticeable approximately 2.5 ms after the start of injection.
Christopher Geschwindner; Patrick Kranz; Cooper Welch; Marius Schmidt; Benjamin Boehm; Sebastian Kaiser; Joaquin De La Morena. Analysis of the interaction of Spray G and in-cylinder flow in two optical engines for late gasoline direct injection. International Journal of Engine Research 2019, 21, 169 -184.
AMA StyleChristopher Geschwindner, Patrick Kranz, Cooper Welch, Marius Schmidt, Benjamin Boehm, Sebastian Kaiser, Joaquin De La Morena. Analysis of the interaction of Spray G and in-cylinder flow in two optical engines for late gasoline direct injection. International Journal of Engine Research. 2019; 21 (1):169-184.
Chicago/Turabian StyleChristopher Geschwindner; Patrick Kranz; Cooper Welch; Marius Schmidt; Benjamin Boehm; Sebastian Kaiser; Joaquin De La Morena. 2019. "Analysis of the interaction of Spray G and in-cylinder flow in two optical engines for late gasoline direct injection." International Journal of Engine Research 21, no. 1: 169-184.
José M. García‐Oliver; Antonio García; Joaquin Morena; Javier Monsalve‐Serrano. Application of a one‐dimensional spray model to teach diffusion flame fundamentals for engineering students. Computer Applications in Engineering Education 2019, 27, 1202 -1216.
AMA StyleJosé M. García‐Oliver, Antonio García, Joaquin Morena, Javier Monsalve‐Serrano. Application of a one‐dimensional spray model to teach diffusion flame fundamentals for engineering students. Computer Applications in Engineering Education. 2019; 27 (5):1202-1216.
Chicago/Turabian StyleJosé M. García‐Oliver; Antonio García; Joaquin Morena; Javier Monsalve‐Serrano. 2019. "Application of a one‐dimensional spray model to teach diffusion flame fundamentals for engineering students." Computer Applications in Engineering Education 27, no. 5: 1202-1216.
This article describes the main results of an investigation about counter-bore injector nozzle impact on the combustion process in a modern Euro 6 diesel engine. First, hydraulic and spray visualization tests have been performed, showing a potential advantage of such nozzle design in fuel–air mixing efficiency. Then, combustion performance has been assessed on a GM-designed 1.6-L four-cylinder engine. The engine has been installed on a dynamometric test bench and instrumented with an AVL cylinder pressure transducer for heat release rate analysis, as well as HORIBA MEXA gas analyzer for exhaust emissions and AVL 415 Smoke Meter. Engine efficiency and emissions have been analyzed on four different part-load steady-state points, representative of New European Driving Cycle and Worldwide harmonized Light duty Test Cycle certification cycles, and covering engine speeds from 1250 to 2000 r/min and brake mean effective pressure between 0.2 and 1.4 MPa. Results of indicated analysis show that counter-bore nozzles have significant differences in terms of pilot injection combustion at low load points, which in turn lead to a better ignition and shorter combustion of the main injection. In addition, an improvement of diffusive combustion is observed as load increases. Because of both, fuel consumption is reduced by approximately 1% with respect to a standard nozzle. Finally, an appreciable decrease in engine exhaust emissions has been recorded, especially in terms of particulate matter and hydrocarbon emissions. This reduction has been linked to the improvement of fuel–air mixing promoted by the counter-bore nozzle previously observed.
Raul Payri; Joaquin De La Morena; Javier Monsalve-Serrano; Francesco Concetto Pesce; Alberto Vassallo. Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application. International Journal of Engine Research 2018, 20, 46 -57.
AMA StyleRaul Payri, Joaquin De La Morena, Javier Monsalve-Serrano, Francesco Concetto Pesce, Alberto Vassallo. Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application. International Journal of Engine Research. 2018; 20 (1):46-57.
Chicago/Turabian StyleRaul Payri; Joaquin De La Morena; Javier Monsalve-Serrano; Francesco Concetto Pesce; Alberto Vassallo. 2018. "Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application." International Journal of Engine Research 20, no. 1: 46-57.
A Ford 1.8 l high-speed diesel engine (HSDI) is utilized for a thorough investigation of split dual injection with two included-angle nozzles. The system is equipped with variable-geometry turbocharging (VGT) and high-pressure common-rail (HPCR) technologies which lets multi-injections per cycle. The share of fuel between pulses is divided into three portions of 70-30, 80-20, and 90-10 with included angles of 10, 20, and 30 while the dwell time between pulses are 5CA, 10CA, 15CA, and 20CA. The results demonstrate that the optimum option is 70 (5) 30-30deg “split injection with 70-30% of mass share, dwell of 5CA and with 30° of nozzle divergence” with the best homogeneity of mixture (UI = 0.9742) and peak temperature (Tmax = 2011.58 K) that yield maximum thermo-mechanical exergy amounting to 439 J. In addition, the highest amount of accumulative irreversibility happens for 90 (10) 10–20 deg. It is found that there is a relation between mixture uniformity and accumulative work/heat exergy, whereas a high rate of pressure rise (RPR) contribute to irreversibility rate or exergy destruction in diesel engine, i.e. RPR (80-20) = 904.67 kPa/deg. More, the results are in agreement with literature reporting that higher in-cylinder temperature (Tmax (70 (5) 30-30deg) = 2011.58 K)) can possibly decrease the accumulative irreversibility.
Hadi Taghavifar; Arash Nemati; F.J. Salvador; J. De la Morena. Improved mixture quality by advanced dual-nozzle, included-angle split injection in HSDI engine: Exergetic exploration. Energy 2018, 167, 211 -223.
AMA StyleHadi Taghavifar, Arash Nemati, F.J. Salvador, J. De la Morena. Improved mixture quality by advanced dual-nozzle, included-angle split injection in HSDI engine: Exergetic exploration. Energy. 2018; 167 ():211-223.
Chicago/Turabian StyleHadi Taghavifar; Arash Nemati; F.J. Salvador; J. De la Morena. 2018. "Improved mixture quality by advanced dual-nozzle, included-angle split injection in HSDI engine: Exergetic exploration." Energy 167, no. : 211-223.
This paper conducts an investigation on the temperature variations experienced by the fuel when it expands through the calibrated orifices of a commercial diesel injector. Experimental results of the temperature change across a calibrated orifice upon expansion, extracted from a previous work, are compared to the temperature predicted by computational fluid dynamic simulations under the assumption of adiabatic flow, with no heat transfer to the surroundings. The comparison points out that the simulations are able to predict the thermal effects taking place inside the orifice. Once the model is validated, the flow morphology is analyzed to explain the trends observed in the fuel temperature change across the orifice depending on the operating conditions. Two opposed effects take place inside the orifice: on the one hand, the flow is cooled in the orifice core due to depressurization; on the other hand, the fuel is importantly heated near the walls due to viscous friction. As expected, the net effect on the outlet temperature mainly depends on the orifice discharge coefficient, governed by the orifice geometry and the flow regime (Reynolds number) induced by the injection conditions. Next, the analysis is extended to a diesel nozzle, considering that the higher pressure drops achieved in it are expected to induce even more important thermal effects. The two opposed effects also take place inside the orifice. Even though their net effect is similar, the separate effect of each phenomenon is greater, leading to differences that could be relevant for the atomization and spray formation processes. Additionally, the flow pattern shows a non-uniform distribution of the flow inside the nozzle influencing the results from the thermal point of view.
F.J. Salvador; Marcos Carreres; Joaquin De La Morena; E. Martínez-Miracle. Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles. Energy Conversion and Management 2018, 171, 438 -451.
AMA StyleF.J. Salvador, Marcos Carreres, Joaquin De La Morena, E. Martínez-Miracle. Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles. Energy Conversion and Management. 2018; 171 ():438-451.
Chicago/Turabian StyleF.J. Salvador; Marcos Carreres; Joaquin De La Morena; E. Martínez-Miracle. 2018. "Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles." Energy Conversion and Management 171, no. : 438-451.
The geometry of certain parts of diesel injectors is key to the injection, atomization and fuel-air mixing phenomena. Small variations on the geometrical parameters may have a strong influence on the aforementioned processes. Thus, OEMs need to assess their manufacturing tolerances, whereas researchers in the field (both experimentalists and modelers) rely on the accuracy of a certain metrology technique for their studies. In the current paper, an investigation of the capability of different experimental techniques to determine the geometry of a modern diesel fuel injector has been performed. For this purpose, three main elements of the injector have been evaluated: the control volume inlet and outlet orifices, together with the nozzle orifices. While the direct observation of the samples through an optical microscope is only possible for the simplest pieces, both Computed Tomography Scanning and the visualization of silicone molds technique have proven their ability to characterize the most complex internal shapes corresponding to the internal injector elements. Indeed, results indicate that the differences observed among these methodologies for the determination of the control volume inlet orifice diameter and the nozzle orifice dimensions are smaller than the uncertainties related to the experimental techniques, showing that they are both equally accurate. This implies that the choice of a given technique for the particular application of determining the geometry of diesel injectors can be done on the basis of availability, intrusion and costs, rather than on its accuracy.
F. J. Salvador; J. Gimeno; Joaquin De La Morena; Marcos Carreres. Comparison of Different Techniques for Characterizing the Diesel Injector Internal Dimensions. Experimental Techniques 2018, 42, 467 -472.
AMA StyleF. J. Salvador, J. Gimeno, Joaquin De La Morena, Marcos Carreres. Comparison of Different Techniques for Characterizing the Diesel Injector Internal Dimensions. Experimental Techniques. 2018; 42 (5):467-472.
Chicago/Turabian StyleF. J. Salvador; J. Gimeno; Joaquin De La Morena; Marcos Carreres. 2018. "Comparison of Different Techniques for Characterizing the Diesel Injector Internal Dimensions." Experimental Techniques 42, no. 5: 467-472.
In this article, an investigation of a solenoid common-rail injector has been carried out to understand the hydraulic interactions between close-coupled injection events. For this purpose, a one-dimensional model of the injector was developed on GT-SUITE software. The geometrical and hydraulic characteristics of the internal elements of the injector, needed to construct the model, were obtained by means of different custom-made experimental tools. The dynamic behavior of the injector was characterized using an EVI rate of injection meter. The hydraulic results from the model show a good alignment with the experiments for single injections and a varied degree of success for multiple injections. Once the model was validated, it has been used to understand the injector performance under multiple-injection strategies. The mass of a second injection has shown to highly depend on the electrical dwell time, especially at low values, mostly due to the dynamic pressure behavior in the needle seat. The critical dwell time, defined as the minimum electrical dwell time needed to obtain two independent injection events, has been numerically obtained on a wide range of operating conditions and correlated to injection pressure and energizing time of the first injection. Finally, the increase in the needle opening velocity of the second injection compared to the single-injection case has been analyzed for close-coupled injection events.
Raul Payri; Joaquin De La Morena; Vincenzo Pagano; Ali Hussain; Gilbert Sammut; Les Smith. One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector. International Journal of Engine Research 2018, 20, 452 -469.
AMA StyleRaul Payri, Joaquin De La Morena, Vincenzo Pagano, Ali Hussain, Gilbert Sammut, Les Smith. One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector. International Journal of Engine Research. 2018; 20 (4):452-469.
Chicago/Turabian StyleRaul Payri; Joaquin De La Morena; Vincenzo Pagano; Ali Hussain; Gilbert Sammut; Les Smith. 2018. "One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector." International Journal of Engine Research 20, no. 4: 452-469.
Currently, diesel engines are calibrated using more and more complex multiple injection strategies. Under these conditions, the characteristics of the flow exiting the fuel injector are strongly affected by the transient interaction between the needle, the sac volume and the orifices, which are not yet clear. In the current paper, a methodology combining a 1D injector model and 3D-CFD simulations is proposed. First, the characteristics of the nozzle flow have been experimentally assessed in transient conditions by means of injection rate and momentum flux measurements. Later, the 3D-CFD modeling approach has been validated at steady-state fixed lift conditions. Finally, a previously developed 1D injector model has been used to extract the needle lift profiles and transient pressure boundary conditions used for the full-transient 3D-CFD simulations, using adaptive mesh refinement (AMR) strategies to be able to simulate the complete injection rate starting from 1 µm lift.
F. J. Salvador; J. De La Morena; G. Bracho; D. Jaramillo. Computational investigation of diesel nozzle internal flow during the complete injection event. Journal of the Brazilian Society of Mechanical Sciences and Engineering 2018, 40, 153 .
AMA StyleF. J. Salvador, J. De La Morena, G. Bracho, D. Jaramillo. Computational investigation of diesel nozzle internal flow during the complete injection event. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2018; 40 (3):153.
Chicago/Turabian StyleF. J. Salvador; J. De La Morena; G. Bracho; D. Jaramillo. 2018. "Computational investigation of diesel nozzle internal flow during the complete injection event." Journal of the Brazilian Society of Mechanical Sciences and Engineering 40, no. 3: 153.
R. Payri; F.J. Salvador; J. De la Morena; V. Pagano. Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2 – Spray characteristics. Fuel 2018, 213, 215 -221.
AMA StyleR. Payri, F.J. Salvador, J. De la Morena, V. Pagano. Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2 – Spray characteristics. Fuel. 2018; 213 ():215-221.
Chicago/Turabian StyleR. Payri; F.J. Salvador; J. De la Morena; V. Pagano. 2018. "Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2 – Spray characteristics." Fuel 213, no. : 215-221.
F.J. Salvador; J.J. Lopez; J. De La Morena; M. Crialesi-Esposito; Francisco Javier Salvador Rubio. Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance. Fuel 2018, 213, 207 -214.
AMA StyleF.J. Salvador, J.J. Lopez, J. De La Morena, M. Crialesi-Esposito, Francisco Javier Salvador Rubio. Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance. Fuel. 2018; 213 ():207-214.
Chicago/Turabian StyleF.J. Salvador; J.J. Lopez; J. De La Morena; M. Crialesi-Esposito; Francisco Javier Salvador Rubio. 2018. "Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance." Fuel 213, no. : 207-214.
The motion of the needle during the injection process of a diesel injector has a marked influence on the internal flow, the fuel characteristics at the nozzle exit, the spray pattern and the fuel–air mixing process. The current paper is focused on the computational study of the internal flow and cavitation phenomena during the injection process, with inclusion of the opening where the needle is working at partial lifts. This study has been performed with a homogeneous equilibrium model (OpenFOAM) customized by the authors to simulate the real motion of the needle. The first part of the study covers the analysis of the whole injection process with a moving mesh using the boundary conditions provided by a one-dimensional (1D) model of the injector created in AMESim. This 1D model has offered the possibility of reproducing the movement of the needle with real lift law and real injection pressure evolution during the injection. Thus, it has been possible to compare the injection rate profiles provided by OpenFOAM against those obtained both in AMESim and experimentally. The second part compares the differences in mass flow, momentum flux, effective velocity and cavitation appearance between steady (fixed lifts) and transient (moving mesh) simulations. The aim of this comparison is to establish the differences between these two approaches. On the one hand is a more realistic approach in its use of transient simulations of the injection process and where the needle movement is taken into account. On the other hand, is the use of steady simulations at partial needle lifts. This analysis could be of interest to researchers devoted to the study of the diesel injection process since it could help to delimit the uncertainties involved in using the second approach which is more easily carried out, versus the first which is supposed to provide more realistic results.
Fj Salvador; Joaquin De La Morena; Marco Crialesi-Esposito; J Martínez-López. Comparative study of the internal flow in diesel injection nozzles at cavitating conditions at different needle lifts with steady and transient simulations approaches. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2017, 232, 1060 -1078.
AMA StyleFj Salvador, Joaquin De La Morena, Marco Crialesi-Esposito, J Martínez-López. Comparative study of the internal flow in diesel injection nozzles at cavitating conditions at different needle lifts with steady and transient simulations approaches. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 2017; 232 (8):1060-1078.
Chicago/Turabian StyleFj Salvador; Joaquin De La Morena; Marco Crialesi-Esposito; J Martínez-López. 2017. "Comparative study of the internal flow in diesel injection nozzles at cavitating conditions at different needle lifts with steady and transient simulations approaches." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 8: 1060-1078.
R. Payri; F.J. Salvador; J. De la Morena; V. Pagano. Using a one-dimensional spray model to improve liquid length and ignition delay estimations for diesel flames. Applied Thermal Engineering 2017, 124, 1090 -1102.
AMA StyleR. Payri, F.J. Salvador, J. De la Morena, V. Pagano. Using a one-dimensional spray model to improve liquid length and ignition delay estimations for diesel flames. Applied Thermal Engineering. 2017; 124 ():1090-1102.
Chicago/Turabian StyleR. Payri; F.J. Salvador; J. De la Morena; V. Pagano. 2017. "Using a one-dimensional spray model to improve liquid length and ignition delay estimations for diesel flames." Applied Thermal Engineering 124, no. : 1090-1102.