Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part I -Steady-state operation

[EN] Internal combustion engine developments are more focused on efficiency optimization and emission reduction for the upcoming future. To achieve these goals, technologies like downsizing and downspeeding are needed to be developed according to the requirement. These modifications on thermal engines are able to reduce fuel consumption and CO2 emission. However, implementation of these kind of technologies asks for right and efficient charging systems. This article consists of study of different boosting systems and architectures (single- and two-stage) with combination of different charging systems like superchargers and e-boosters. A parametric study is carried out with a zero-dimensional engine model to analyze and compare the effects of these different architectures on the same base engine. The impact of thermomechanical limits, turbo sizes and other engine development option characterizations are proposed to improve fuel consumption, maximum power and performance of the downsized/downspeeded diesel engines.Galindo, J.; Climent, H.; Varnier, O.; Patil, CY. (2018). Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part I -Steady-state operation. International Journal of Engine Research. 19(8):854-872. https://doi.org/10.1177/1468087417731654S85487219

Control-oriented modelling of three-way catalytic converter for fuel-to-air ratio regulation in spark ignited engines

[EN] The purpose of this paper is to introduce a grey-box model of three-way catalytic converter, which is capable of estimating the oxygen storage level to aid the fuel-to-air ratio control in spark ignited engines. As it is well-known, the prime parameter that drives the transient dynamics in current three-way catalytic converter is their capability to store a certain amount of oxygen, then allowing to oxidize some pollutant species such as carbon monoxide or hydrocarbons even at rich conditions during short periods of time. Since oxygen storage level is considered a good indicator of the catalyst state but it cannot be directly measured, a model based real-time capable estimation like the one proposed in this paper could be valuable. The model accounts for oxygen storing as well as oxidation and reduction of the main species involved, taking as inputs fuel-to-air equivalence ratio, air mass flow, temperature and gas composition at three-way catalyst inlet. From these inputs, oxygen storage level and brick temperature are calculated as model states, which finally provide the gas composition downstream of the catalyst as output. In addition, a simplified model of narrowband lambda sensor is included, it provides a voltage from gas composition at the outlet of the catalyst and allows to assess the model behaviour by comparison with the on-board lambda sensor measurements. Finally, the validation of the model performance by means of experimental test as well as different practical cases, where the benefits of oxygen storage level estimation plays a key role, are introduced.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors acknowledge the support of Spanish Ministerio de Economía, Industria y Competitividad through project TRA2016-78717-R.Guardiola, C.; Climent, H.; Pla Moreno, B.; Real, M. (2019). Control-oriented modelling of three-way catalytic converter for fuel-to-air ratio regulation in spark ignited engines. Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering. 233(14):3758-3774. https://doi.org/10.1177/0954407019833822S3758377423314Auckenthaler, T. S., Onder, C. H., & Geering, H. P. (2004). Aspects of Dynamic Three-Way Catalyst Behaviour Including Oxygen Storage. IFAC Proceedings Volumes, 37(22), 331-336. doi:10.1016/s1474-6670(17)30365-8Yang, H., Shu, G., Tian, H., Ma, X., Chen, T., & Liu, P. (2018). Optimization of thermoelectric generator (TEG) integrated with three-way catalytic converter (TWC) for harvesting engine’s exhaust waste heat. Applied Thermal Engineering, 144, 628-638. doi:10.1016/j.applthermaleng.2018.07.091Koltsakis, G. C., Konstantinidis, P. A., & Stamatelos, A. M. (1997). Development and application range of mathematical models for 3-way catalytic converters. Applied Catalysis B: Environmental, 12(2-3), 161-191. doi:10.1016/s0926-3373(96)00073-2Zygourakis, K. (1989). Transient operation of monolith catalytic converters: a two-dimensional reactor model and the effects of radially nonuniform flow distributions. Chemical Engineering Science, 44(9), 2075-2086. doi:10.1016/0009-2509(89)85143-7Coxeter, H. S. M. (1993). Cyclotomic integers, nondiscrete tessellations, and quasicrystals. Indagationes Mathematicae, 4(1), 27-38. doi:10.1016/0019-3577(93)90049-5Konstantas, G., & Stamatelos, A. M. (2007). Modelling three-way catalytic converters: An effort to predict the effect of precious metal loading. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 221(3), 355-373. doi:10.1243/09544070jauto329Pontikakis, G. N., Konstantas, G. S., & Stamatelos, A. M. (2004). Three-Way Catalytic Converter Modeling as a Modern Engineering Design Tool. Journal of Engineering for Gas Turbines and Power, 126(4), 906-923. doi:10.1115/1.1787506Kumar, P., Gu, T., Grigoriadis, K., Franchek, M., & Balakotaiah, V. (2014). Spatio-temporal dynamics of oxygen storage and release in a three-way catalytic converter. Chemical Engineering Science, 111, 180-190. doi:10.1016/j.ces.2014.02.014Auckenthaler, T. S., Onder, C. H., Geering, H. P., & Frauhammer, J. (2004). Modeling of a Three-Way Catalytic Converter with Respect to Fast Transients of λ-Sensor Relevant Exhaust Gas Components. Industrial & Engineering Chemistry Research, 43(16), 4780-4788. doi:10.1021/ie034242uNievergeld, A. J. L., Selow, E. R. v., Hoebink, J. H. B. J., & Marin, G. B. (1997). Simulation of a catalytic converter of automotive exhaust gas under dynamic conditions. Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis, Proceedings of the International Symposium, 449-458. doi:10.1016/s0167-2991(97)80431-4Oh, S. H., & Cavendish, J. C. (1982). Transients of monolithic catalytic converters. Response to step changes in feedstream temperature as related to controlling automobile emissions. Industrial & Engineering Chemistry Product Research and Development, 21(1), 29-37. doi:10.1021/i300005a006Chan, S. H., & Hoang, D. L. (1999). Heat transfer and chemical reactions in exhaust system of a cold-start engine. International Journal of Heat and Mass Transfer, 42(22), 4165-4183. doi:10.1016/s0017-9310(99)00064-2Sabatini, S., Gelmini, S., Hoffman, M. A., & Onori, S. (2017). Design and experimental validation of a physics-based oxygen storage — thermal model for three way catalyst including aging. Control Engineering Practice, 68, 89-101. doi:10.1016/j.conengprac.2017.07.007Schürholz, K., Brückner, D., Gresser, M., & Abel, D. (2018). Modeling of the Three-way Catalytic Converter by Recurrent Neural Networks. IFAC-PapersOnLine, 51(15), 742-747. doi:10.1016/j.ifacol.2018.09.166Brandt, E. P., Yanying Wang, & Grizzle, J. W. (2000). Dynamic modeling of a three-way catalyst for SI engine exhaust emission control. IEEE Transactions on Control Systems Technology, 8(5), 767-776. doi:10.1109/87.865850Shaw, B. T., Fischer, G. D., & Hedrick, J. K. (2002). A SIMPLIFIED COLDSTART CATALYST THERMAL MODEL TO REDUCE HYDROCARBON EMISSIONS. IFAC Proceedings Volumes, 35(1), 307-312. doi:10.3182/20020721-6-es-1901.01519Bickel, J., Odendall, B., Eigenberger, G., & Nieken, U. (2017). Oxygen storage dominated three-way catalyst modeling for fresh catalysts. Chemical Engineering Science, 160, 34-53. doi:10.1016/j.ces.2016.11.016Kiwitz, P., Onder, C., & Guzzella, L. (2012). Control-oriented modeling of a three-way catalytic converter with observation of the relative oxygen level profile. Journal of Process Control, 22(6), 984-994. doi:10.1016/j.jprocont.2012.04.014Kumar, P., Makki, I., Kerns, J., Grigoriadis, K., Franchek, M., & Balakotaiah, V. (2012). A low-dimensional model for describing the oxygen storage capacity and transient behavior of a three-way catalytic converter. Chemical Engineering Science, 73, 373-387. doi:10.1016/j.ces.2011.12.001Gong, J., Wang, D., Li, J., Currier, N., & Yezerets, A. (2017). Dynamic oxygen storage modeling in a three-way catalyst for natural gas engines: A dual-site and shrinking-core diffusion approach. Applied Catalysis B: Environmental, 203, 936-945. doi:10.1016/j.apcatb.2016.11.005Ramanathan, K., & Sharma, C. S. (2011). Kinetic Parameters Estimation for Three Way Catalyst Modeling. Industrial & Engineering Chemistry Research, 50(17), 9960-9979. doi:10.1021/ie200726jOlsson, L., & Andersson, B. (2004). Kinetic Modelling in Automotive Catalysis. Topics in Catalysis, 28(1-4), 89-98. doi:10.1023/b:toca.0000024337.50617.8eMöller, R., Votsmeier, M., Onder, C., Guzzella, L., & Gieshoff, J. (2009). Is oxygen storage in three-way catalysts an equilibrium controlled process? Applied Catalysis B: Environmental, 91(1-2), 30-38. doi:10.1016/j.apcatb.2009.05.003Rink, J., Meister, N., Herbst, F., & Votsmeier, M. (2017). Oxygen storage in three-way-catalysts is an equilibrium controlled process: Experimental investigation of the redox thermodynamics. Applied Catalysis B: Environmental, 206, 104-114. doi:10.1016/j.apcatb.2016.12.052Auckenthaler, T. S., Onder, C. H., & Geering, H. P. (2002). CONTROL-ORIENTED INVESTIGATION OF SWITCH-TYPE AIR/FUEL RATIO SENSORS. IFAC Proceedings Volumes, 35(1), 331-336. doi:10.3182/20020721-6-es-1901.0152

Optimal control as a method for diesel engine efficiency assessment including pressure and NOx constraints

[EN] The present paper studies the optimal heat release law in a Diesel engine to maximise the indicated efficiency subject to different constraints, namely: maximum cylinder pressure, maximum cylinder pressure derivative, and NOx emission restrictions. With this objective, a simple but also representative model of the combustion process has been implemented. The model consists of a OD energy balance model aimed to provide the pressure and temperature evolutions in the high pressure loop of the engine thermodynamic cycle from the gas conditions at the intake valve closing and the heat release law. The gas pressure and temperature evolutions allow to compute the engine efficiency and NOx emissions. The comparison between model and experimental results shows that despite the model simplicity, it is able to reproduce the engine efficiency and NOx emissions. After the model identification and validation, the optimal control problem is posed and solved by means of Dynamic Programming (DP). Also, if only pressure constraints are considered, the paper proposes a solution that reduces the computation cost of the DP strategy in two orders of magnitude for the case being analysed. The solution provides a target heat release law to define injection strategies but also a more realistic maximum efficiency boundary than the ideal thermodynamic cycles usually employed to estimate the maximum engine efficiency. (C) 2017 Elsevier Ltd. All rights reserved.Thanks are due to the Ministerio de Economia y Competitividad by its financial support through project mu-Balance (TRA2013-41348-R).Guardiola, C.; Climent, H.; Plá Moreno, B.; Reig, A. (2017). Optimal control as a method for diesel engine efficiency assessment including pressure and NOx constraints. Applied Thermal Engineering. 117:452-461. https://doi.org/10.1016/j.applthermaleng.2017.02.056S45246111

Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part II - Transient operation

[EN] Nowadays, internal combustion engine developments are focused on efficiency optimization and emission reduction. Increasing focus on world harmonized ways to determine the performance and emissions on Worldwide harmonized Light vehicles Test Procedure cycles, it is essential to optimize the engines for transient operations. To achieve these objectives, the downsized or downspeeded engines are required, which can reduce fuel consumption and pollutant emissions. However, these technologies ask for efficient charging systems. This article consists of the study of different boosting architectures (single stage and two stage) with a combination of different charging systems like superchargers and e-boosters. A parametric study has been carried out with a zero-dimensional engine model to analyze and compare different architectures on the different engine displacements. The impact of thermomechanical limits, turbo sizes and other engine development option characterizations is proposed to improve fuel consumption, maximum power and performance of the downsized/downspeeded diesel engines during the transient operations.Galindo, J.; Climent, H.; Varnier, O.; Patil, CY. (2018). Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part II - Transient operation. International Journal of Engine Research. 19(8):873-885. https://doi.org/10.1177/1468087417732264S87388519

EGR transient operations in highly dynamic driving cycles

[EN] EGR is one of the proven and well tested strategies within the specific operating range of the engine. Necessity of an implementation of this exhaust gas recirculation all over the engine operating range is emerging. Therefore, a systematic study has been carried out to identify the specific and frequent transient operations on newly developed dynamic cycles like WLTC and RDE. To perform detailed observations, these transients are imitated individually on the diesel engine test bench. High frequency gas analyzers are used to track the instantaneous CO2 and NOx concentration respectively at the intake and exhaust lines of the engine. A parametric study has been carried out using different valve movement profiles of the LPEGR and HPEGR during severe engine load change operations. An analysis is presented suggesting the best suited valve control during these harsh transients which can be helpful for transient calibration of a turbocharged diesel engine. The effect of length of Long route LPEGR line is also acknowledged. This study reveals the dynamic behavior of a diesel engine during transient operation with exhaust gas recirculation. It outlines the trade-off between performance and NOx emission and opacity for the initial phase of the transient before acquiring the steady state situation.Galindo, J.; Climent, H.; Pla Moreno, B.; Patil, CY. (2020). EGR transient operations in highly dynamic driving cycles. International Journal of Automotive Technology. 21(4):865-879. https://doi.org/10.1007/s12239-020-0084-xS865879214Asad, U., Tjong, J. and Zheng, M. (2014). Exhaust gas recirculation–Zero dimensional modelling and characterization for transient diesel combustion control. Energy Conversion and Management, 86, 309–324.Balau, A., Kooijman, D., Vazquez Rodarte, I. and Ligterink, N. (2015). Stochastic real-world drive cycle generation based on a two stage Markov chain approach. SAE Int. J. 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United States.Buchwald, R., Lautrich, G., Maiwald, O. and Sommer, A. (2006). Boost and EGR system for the highly premixed diesel combustion. SAE Paper No. 2006-01-0204.Chung, J., Kim, H. and Sunwoo, M. (2018). Reduction of transient NOx emissions based on set-point adaptation of real-time combustion control for light-duty diesel engines. Applied Thermal Engineering, 137, 729–738.Darlington, A., Glover, K. and Collings, N. (2006). A simple diesel engine air-path model to predict the cylinder charge during transients: Strategies for reducing transient emissions spikes. SAE Paper No. 2006-01-3373Daya, R., Hoard, J., Chanda, S. and Singh, M. (2017). Insulated catalyst with heat storage for real-world vehicle emissions reduction. Int. J. Engine Research18, 9, 886–899.Donateo, T. and Giovinazzi, M. (2017). Building a cycle for real driving emissions. Energy Procedia, 126, 891–898.European Parliament & Council of the European Union (2016). Commission Regulation (EU) 2016/427 of 10 March 2016 Amending Regulation (EC) No 692/2008 as Regards Emissions from Light Passenger and Commercial Vehicles (Euro 6) (Text with EEA Relevance). Official J. European Union, 82(31/03/2016), 1–98.Giakoumis, E. G., Rakopoulos, C. D., Dimaratos, A. M. and Rakopoulos, D. C. (2012). Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends. Progress in Energy and Combustion Science38, 5, 691–715.Gong, Q., Midlam-Mohler, S., Marano, V., Rizzoni, G. and Guezennec, Y. (2010). Statistical analysis of PHEV fleet data. Proc. IEEE Vehicle Power and Propulsion Conf., Lille, France.Heuwetter, D., Glewen, W., Meyer, C., Foster, D. E., Andrie, M. and Krieger, R. (2011). Effects of low pressure EGR on transient air system performance and emissions for low temperature diesel combustion. SAE Paper No. 2011-24-0062.Khalef, M. S., Soba, A. and Korsgren, J. (2016). Study of EGR and turbocharger combinations and their influence on diesel engine’s efficiency and emissions. SAE Paper No. 2016-01-0676.Kooijman, D. G., Balau, A. E., Wilkins, S., Ligterink, N. and Cuelenaere, R. (2015). WLTP random cycle generator. Proc. IEEE Vehicle Power and Propulsion Conf. (VPPC), Montreal, Quebec, Canada.Lakshminarayanan, P. A. and Aswin, S. (2017). Estimation of particulate matter from smoke, oil consumption and fuel sulphur. SAE Paper No. 2017-01-7002.Lana, C. A., Kappaganthu, K., Kothandaraman, G. and PerfettoKarthik, D. J. S. C. G. H. D. K. (2016). US20160237928A1. United States.Leach, F. C. P., Davy, M. and Peckham, M. (2019). Cyclic NO2: NOx ratio from a diesel engine undergoing transient load steps. Int. J. Engine Research.Leach, F., Davy, M. and Peckham, M. (2018). Cycle-tocycle NO and NOx emissions from a HSDI diesel engine. Proc. ASME Internal Combustion Engine Division Fall Technical Conf., San Diego, California, USA.Liu, F. and Pfeiffer, J. (2015). Estimation algorithms for low pressure cooled EGR in spark-ignition engines. SAE Paper No. 2015-01-1620.Liu, F., Pfeiffer, J. M., Caudle, R., Marshall, P. and Olin, P. (2016). Low pressure cooled EGR transient estimation and measurement for an turbocharged SI engine. SAE Paper No. 2016-01-0618.Luján, J. M., Climent, H., Ruiz, S. and Moratal, A. (2018a). Influence of ambient temperature on diesel engine raw pollutants and fuel consumption in different driving cycles. Int. J. Engine Research20, 8–9, 877–888.Luján, J. M., Bermúdez, V., Dolz, V. and Monsalve-Serrano, J. (2018b). An assessment of the real-world driving gaseous emissions from a Euro 6 light-duty diesel vehicle using a portable emissions measurement system (PEMS). Atmospheric Environment, 174, 112–121.Luján, J. M., Climent, H., Arnau, F. J. and Miguel-García, J. (2018c). Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines. Applied Thermal Engineering, 137, 184–192.Luján, J. M., Guardiola, C., Pla, B. and Reig, A. (2015). Switching strategy between HP (high pressure)- and LPEGR (low pressure exhaust gas recirculation) systems for reduced fuel consumption and emissions. Energy90, Part 2, 1790–1798.Maiboom, A., Tauzia, X. and Hétet, J. F. (2008). Experimental study of various effects of exhaust gas recirculation (EGR) on combustion and emissions of an automotive direct injection diesel engine. Energy33, 1, 22–34.Park, J. and Choi, J. (2016). Optimization of dual-loop exhaust gas recirculation splitting for a light-duty diesel engine with model-based control. Applied Energy, 181, 268–277.Park, J., Song, S. and Lee, K. S. (2015). Numerical investigation of a dual-loop EGR split strategy using a split index and multi-objective Pareto optimization. Applied Energy, 142, 21–32.Park, Y. and Bae, C. (2014). Experimental study on the effects of high/low pressure EGR proportion in a passenger car diesel engine. Applied Energy, 133, 308–316.Reifarth, S. and Angstrom, H.-E. (2009). Transient EGR in a long-route and short-route EGR system. Proc. ASME Internal Combustion Engine Division Spring Technical Conf., Milwaukee, Wisconsin, USA.Reifarth, S. and Angstrom, H.-E. (2010). Transient EGR in a high-speed DI diesel engine for a set of different EGRroutings. SAE Paper No. 2010-01-1271.Serrano, J. R., Climent, H., Guardiola, C. and Piqueras, P. (2009). Methodology for characterisation and simulation of turbocharged diesel engines combustion during transient operation. Part 2: Phenomenological combustion simulation. Applied Thermal Engineering29, 1, 150–158.Shutty, J. (2009). Control strategy optimization for hybrid EGR engines. SAE Paper No. 2009-01-1451.Soltis, R., Hilditch, J., Clark, T., House, C., Gerhart, M. and Surnilla, G. (2016). Intake oxygen sensor for EGR measurement. SAE Paper No. 2016-01-1070.Sutela, C., Collings, N. and Hands, T. (2000). Real time CO2 measurement to determine transient intake gas composition under EGR conditions. SAE Paper No. 2000-01-2953.Thunis, P., Lefebvre, W., Weiss, M., Vranckx, S., Clappier, A., Degraeuwe, B. and Janssen, S. (2017). Impact of passenger car NOX emissions on urban NO2 pollution–Scenario analysis for 8 European cities. Atmospheric Environment, 171, 330–337.Triantafyllopoulos, G., Katsaounis, D., Karamitros, D., Ntziachristos, L. and Samaras, Z. (2018). Experimental assessment of the potential to decrease diesel NOx emissions beyond minimum requirements for Euro 6 real drive emissions (RDE) compliance. Science of the Total Environment, 618, 1400–1407.Tutuianu, M., Bonnel, P., Ciuffo, B., Haniu, T., Ichikawa, N., Marotta, A., Pavlovic, J. and Steven, H. (2015). Development of the World-wide harmonized Light duty Test Cycle (WLTC) and a possible pathway for its introduction in the European legislation. Transportation Research Part D: Transport and Environment, 40, 61–75.Yamada, H., Misawa, K., Suzuki, D., Tanaka, K., Matsumoto, J., Fujii, M. and Tanaka, K. (2011). Detailed analysis of diesel vehicle exhaust emissions: Nitrogen oxides, hydrocarbons and particulate size distributions. Proc. Combustion Institute33, 2, 2895–2902.Yang, L., Franco, V., Mock, P., Kolke, R., Zhang, S., Wu, Y. and German, J. (2015). Experimental assessment of NOx emissions from 73 Euro 6 diesel passenger cars. Environmental Science and Technology49, 24, 14409–14415.Zamboni, G. and Capobianco, M. (2012). Experimental study on the effects of HP and LP EGR in an automotive turbocharged diesel engine. Applied Energy, 94, 117–128.Zamboni, G., Moggia, S. and Capobianco, M. (2017). Effects of a dual-loop exhaust gas recirculation system and variable nozzle turbine control on the operating parameters of an automotive diesel engine. Energies10, 1, 47

Multi-objective optimization of a bottoming Organic Rankine Cycle (ORC) of gasoline engine using swash-plate expander

This paper presents a mathematical model of a bottoming Organic Rankine Cycle coupled to a 2 l turbocharged gasoline engine to optimize the cycle from a thermo-economic and sizing point of view. These criteria were optimized with different cycle values. Therefore, a methodology to optimize the ORC coupled to Waste Heat Recovery systems in vehicle applications is presented using a multiobjective optimization algorithm. Multi-objective optimization results show that the optimum solution depend on the importance of each objective to the final solution. Considering thermo-economic criteria as the main objective, greater sizes will be required. Considering sizing criteria as the main objective, higher thermo-economic parameters will be obtained. Therefore, in order to select a single-solution from the Pareto frontier, a multiple attribute decision-making method (TOPSIS) was implemented in order to take into account the preferences of the Decision Maker. Considering the weight factors 0.5 for Specific Investment Cost (SIC), 0.3 for the area of the heat exchangers (Atot) and 0.2 for Volume Coefficient (VC) and the boundaries of this particular application, the result is optimized with values of 0.48 m2 (Atot), 2515 /kW (SIC) and 2.62 MJ/m3 (VC). Moreover, the profitability of the project by means of the Net Present Value and the Payback has been estimated.This work is part of a research project called "Evaluation of bottoming cycles in IC engines to recover waste heat energies" funded by a National Project of the Spanish Government with reference TRA2013-46408-R. Authors want to acknowledge the "Apoyo para la investigacion y Desarrollo (PAID)" grant for doctoral studies (FPI S2 2015 1067). Authors acknowledge to ModeFRONTIER (ESTECO) because its support.Galindo, J.; Climent, H.; Dolz Ruiz, V.; Royo-Pascual, L. (2016). Multi-objective optimization of a bottoming Organic Rankine Cycle (ORC) of gasoline engine using swash-plate expander. Energy Conversion and Management. 126:1054-1065. https://doi.org/10.1016/j.enconman.2016.08.053S1054106512

A New Model for Matching Advanced Boosting Systems to Automotive Diesel Engines

[EN] Boosting technologies have been key enablers for automotive engines development through downsizing and downspeeding. In this situation, numerous multistage boosting systems have appeared in the last decade. The complexity arising from multistage architectures requires an efficient matching methodology to obtain the best overall powertrain performance. The paper presents a model aimed to choose the best 2-stage boosting system architecture able to meet required criteria on boosting pressure, EGR ratios for both short and long route loops while respecting the engine thermo-mechanical limits such as in-cylinder pressure, compressor outlet temperature and exhaust manifold temperature. The model includes filling-and-emptying 0D elements together with mean value. The engine model is set in a way that, for given requirements and boosting system layout, calculates in seconds if the requirements will be achieved and the position of variable geometry, waste-gate, EGR and by-pass valves. The model is thus inversed thanks to a new representation of turbine maps that converts the classical iterative matching procedure in straight forward. The model can be also used in a predictive manner to calculate the engine transient response. The model has been calibrated to 3 different turbocharged diesel engines. The model gives good results provided that wave effects are not important. This is the case of compact exhaust manifolds, typically used in turbocharged diesel engines, below 3500 rpm. Tuned intake air lines can be taken into account through a tuning parameter affecting boosting pressure. An example is given in the paper for the matching procedure in a 2-stage, double route EGR, including steady and transient results.This work has been partially financed by the Univeristat Politècnica de València through the Programa de Apoyo a la Investigación y Desarrollo 2012, project PAID-06-2012 DECOAH.Galindo, J.; Luján, JM.; Climent, H.; Guardiola, C.; Varnier, O. (2014). A New Model for Matching Advanced Boosting Systems to Automotive Diesel Engines. SAE International Journal of Engines. 7(1):1-14. https://doi.org/10.4271/2014-01-1078S1147

Experimental Ditching Loads on Aeronautical Flexible Structures

Ditching is an aircraft emergency condition that ends with the planned impact of the aircraft against water. Four main phases may be considered in a ditching event: Approach, Impact, Landing and Floatation This paper addresses some aspects of the second phase, an extreme case of fluid-structure coupling were high pressures may be developed during the impact of the sliding aircraft with water, which in turn may cause rupture of the structure, jeopardizing the required safe evacuation of crew and passengers. For completeness, the paper recalls a description of the ditching tests performed within the European funded research project SMAES. These tests were first used to derive a synthetic expression of the ditching loads based on rigid plates measurements. For flexible plates, these synthetic pressures are in turn corrected using local deformation (in terms of local delta-pitch and local delta-z deformation) in an iterative process. When comparing the deformations obtained using Finite Element Method simulation and the corrected synthetic pressures versus deformation measurements, the results show very good comparison of deformation shape time histories, good comparison of time of occurrence of peak deformation in each pick-up and only fair comparison in terms of deformation levels

Assessment of Variable Geometry Orifice Compressor Technology Impact in a New Generation of Compression Ignition Powertrains at Low-End and Transient Operation

[EN] Surge is a phenomenon that limits the operating range of the compressor at low engine speeds and high boost pressure in turbocharged powertrains. This article assesses two prototype turbochargers of variable geometry orifice (VGO) which compensate for the limitation of the boost pressure at low engine speeds. The VGO prototypes modify the inlet compressor section, extending the compressor characteristic map into lower mass flows (surge limit region). The VGO turbochargers analyzed are also both equipped with variable geometry turbine (VGT) technology. The experiments focus on low-end torque operation ranges in steady and transient engine running conditions. The experimental results are used to validate a 1D physical model. From the modelling perspective, a comprehensive study of the VGO-VGT prototypes is assessed. Results reveal the benefits of VGO technology in terms of attaining higher boost pressure, improved compressor efficiency, and overall engine performance at low engine speeds.This research work has been supported by Grant PDC2021-120821-I00 funded by the Spanish Ministerio de Ciencia e Innovacion-Agencia Estatal de Investigacion (MCIN/AEI/10.13039/501100011033), and by the European Union NextGenerationEU/PRTR.Serrano, J.; Climent, H.; Gómez-Vilanova, A.; Darbhamalla, A.; Guilain, S. (2022). Assessment of Variable Geometry Orifice Compressor Technology Impact in a New Generation of Compression Ignition Powertrains at Low-End and Transient Operation. Applied Sciences. 12(24):1-19. https://doi.org/10.3390/app122412869119122