In-Cylinder Pressure-Based Control of Premixed Dual-Fuel Combustion

[ES] La actual crisis climática ha instado a la comunidad investigadora y a los fabricantes a brindar soluciones para hacer que el sector del transporte sea más sostenible. De entre las diversas tecnologías propuestas, la combustión a baja temperatura ha sido objeto de una extensa investigación. La combustión premezclada dual-fuel es uno de los conceptos que abordan el compromiso de NOx-hollín en motores de encendido por compresión manteniendo alta eficiencia térmica. Esta combustión hace uso de dos combustibles con diferentes reactividades para mejorar la controlabilidad de este modo de combustión en un amplio rango de funcionamiento. De manera similar a todos los modos de combustión premezclados, esta combustión es sensible a las condiciones de operación y suele estar sujeta a variabilidad cíclica con gradientes de presión significativos. En consecuencia, se requieren estrategias de control avanzadas para garantizar un funcionamiento seguro y preciso del motor. El control en bucle cerrado es una herramienta eficaz para abordar los desafíos que plantea la combustión premezclada dual-fuel. En este tipo de control, para mantener el funcionamiento deseado, las acciones de control se adaptan y corrigen a partir de una retroalimentación con las señales de salida del motor. Esta tesis presenta estrategias de control basadas en la medición de la señal de presión en el cilindro, aplicadas a motores de combustión premezclada dual-fuel. En ella se resuelven diversos aspectos del funcionamiento del motor mediante el diseño de controladores dedicados, haciéndose especial énfasis en analizar e implementar estas soluciones a los diferentes niveles de estratificación de mezcla considerados en estos motores (es decir, totalmente, altamente y parcialmente premezclada). Inicialmente, se diseñan estrategias de control basadas en el procesamiento de la señal de presión en el cilindro y se seleccionan acciones proporcionales-integrales para asegurar el rendimiento deseado del motor sin exceder las limitaciones mecánicas del motor. También se evalúa la técnica extremum seeking para realizar una supervisión de una combustión eficiente y la reducción de emisiones de NOx. Luego se analiza la resonancia de la presión en el cilindro y se implementa un controlador similar a aquel usado para el control de knock para garantizar el funcionamiento seguro del motor. Finalmente, se utilizan modelos matemáticos para diseñar un modelo orientado a control y un observador que tiene como objetivo combinar las señales medidas en el motor para mejorar las capacidades de predicción y diagnóstico en dicha configuración de motor. Los resultados de este trabajo destacan la importancia de considerar el control en bucle cerrado para abordar las limitaciones encontradas en los modos de combustión premezclada. En particular, el uso de la medición de presión en el cilindro muestra la relevancia y el potencial de esta señal para desarrollar estrategias de control complejas y precisas.[CA] L'actual crisi climàtica ha instat a la comunitat investigadora i als fabricants a brindar solucions per a fer que el sector del transport siga més sostenible. D'entre les diverses tecnologies proposades, la combustió a baixa temperatura ha sigut objecte d'una extensa investigació. La combustió premesclada dual-fuel és un dels conceptes que aborden el compromís de NOx-sutge en motors d'encesa per compressió mantenint alta eficiència tèrmica. Aquesta combustió fa ús de dos combustibles amb diferents reactivitats per a millorar la controlabilitat d'aquest tipus de combustió en un ampli rang de funcionament. De manera similar a tots els tipus de combustió premesclada, aquesta combustió és sensible a les condicions d'operació i sol estar subjecta a variabilitat cíclica amb gradients de pressió significatius. En conseqüència, es requereixen estratègies de control avançades per a garantir un funcionament segur i precís del motor. El control en bucle tancat és una eina eficaç per a abordar els desafiaments que planteja la combustió premesclada dual-fuel. En aquesta mena de control, per a mantindre el funcionament desitjat, les accions de control s'adapten i corregeixen a partir d'una retroalimentació amb els senyals d'eixida del motor. Aquesta tesi presenta estratègies de control basades en el mesurament del senyal de pressió en el cilindre, aplicades a motors de combustió premesclada dual-fuel. En ella es resolen diversos aspectes del funcionament del motor mitjançant el disseny de controladors dedicats, fent-se especial èmfasi a analitzar i implementar aquestes solucions als diferents nivells d'estratificació de mescla considerats en aquests motors (és a dir, totalment, altament i parcialment premesclada). Inicialment, es dissenyen estratègies de control basades en el processament del senyal de pressió en el cilindre i se seleccionen accions proporcionals-integrals per a assegurar el rendiment desitjat del motor sense excedir les limitacions mecàniques del motor. També s'avalua la tècnica extremum seeking per a realitzar una supervisió d'una combustió eficient i la reducció d'emissions de NOx. Després s'analitza la ressonància de la pressió en el cilindre i s'implementa un controlador similar a aquell usat per al control de knock per a garantir el funcionament segur del motor. Finalment, s'utilitzen models matemàtics per a dissenyar un model orientat a control i un observador que té com a objectiu combinar els senyals mesurats en el motor per a millorar les capacitats de predicció i diagnòstic en aquesta configuració de motor. Els resultats d'aquest treball destaquen la importància de considerar el control en bucle tancat per a abordar les limitacions trobades en la combustió premesclada. En particular, l'ús del mesurament de pressió en el cilindre mostra la rellevància i el potencial d'aquest senyal per a desenvolupar estratègies de control complexes i precises.[EN] The current climate crisis has urged the research community and manufacturers to provide solutions to make the transportation sector cleaner. Among the various technologies proposed, low temperature combustion has undergone extensive investigation. Premixed dual-fuel combustion is one of the concepts addressing the NOx-soot trade-off in compression ignited engines, while maintaining high thermal efficiency. This combustion makes use of two fuels with different reactivities in order to improve the controllability of this combustion mode over a wide range of operation. Similarly to all premixed combustion modes, this combustion is nevertheless sensitive to the operating conditions and traditionally exhibits cycle-to-cycle variability with significant pressure gradients. Consequently, advanced control strategies to ensure a safe and accurate operation of the engine are required. Feedback control is a powerful approach to address the challenges raised by the premixed dual-fuel combustion. By measuring the output signals from the engine, strategies can be developed to adapt and correct the control actions to maintain the desired operation. This thesis presents control strategies, based on the in-cylinder pressure signal measurement, applied to premixed dual-fuel combustion engines. Various objectives were addressed by designing dedicated controllers, where a special emphasis was made towards analyzing and implementing these solutions to the different levels of mixture stratification considered in these engines (i.e., fully, highly and partially premixed). At first, feedback control strategies based on the in-cylinder pressure signal processing were designed. Proportional-integral actions were selected to ensure the desired engine performance without exceeding the mechanical constraints of the engine. Extremum seeking was evaluated to track efficient combustion phasing and NOx emissions reduction. The in-cylinder pressure resonance was then analyzed and a knock-like controller was implemented to ensure safe operation of the engine. Finally, mathematical models were used to design a control-oriented model and a state observer that aimed to leverage the signals measured in the engine to improve the prediction and diagnostic capabilities in such engine configuration. The results from this work highlighted the importance of considering feedback control to address the limitations encountered in premixed combustion modes. Particularly, the use of the in-cylinder pressure measurement showed the relevance and potential of this signal to develop complex and accurate control strategies.This thesis was financially supported by the Programa Operativo del Fondo Social Europeo (FSE) de la Comunitat Valenciana 2014-2020 through grant ACIF/2018/141.Barbier, ARS. (2022). In-Cylinder Pressure-Based Control of Premixed Dual-Fuel Combustion [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18327

Safe operation of dual-fuel engines using constrained stochastic control

This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087420985109[EN] Premixed combustion strategies have the potential to achieve high thermal efficiency and to lower the engine-out emissions such as NOx. However, the combustion is initiated at several kernels which create high pressure gradients inside the cylinder. Similarly to knock in spark ignition engines, these gradients might be responsible of important pressure oscillations with a harmful potential for the engine. This work aims to analyze the in-cylinder pressure oscillations in a dual-fuel combustion engine and to determine the feedback variables, control actuators, and control approach for a safe engine operation. Three combustion modes were examined: fully, highly, and partially premixed, and three indexes were analyzed to characterize the safe operation of the engine: the maximum pressure rise rate, the ringing intensity, and the maximum amplitude of pressure oscillations (MAPO). Results show that operation constraints exclusively based on indicators such as the pressure rise rate are not sufficient for a proper limitation of the in-cylinder pressure oscillations. This paper explores the use of a knock-like controller for maintaining the resonance index magnitude under a predefined limit where the gasoline fraction and the main injection timing were selected as control variables. The proposed strategy shows the ability to maintain the percentage of cycles exceeding the specified limit at a desired threshold at each combustion mode in all the cylinders.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was financially support by the Programa Operativo del Fondo Social Europeo (FSE) de la Comunitat Valenciana 2014-2020 through grant ACIF/2018/141.Guardiola, C.; Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS. (2022). Safe operation of dual-fuel engines using constrained stochastic control. International Journal of Engine Research. 23(2):285-299. https://doi.org/10.1177/146808742098510928529923

Closed-loop control of a dual-fuel engine working with different combustion modes using in-cylinder pressure feedback

This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419835327.[EN] This work presents a closed-loop combustion control concept using in-cylinder pressure as a feedback in a dual-fuel combustion engine. At low load, reactivity controlled compression ignition combustion was used while a diffusive dual-fuel combustion was performed at higher loads. The aim of the presented controller is to maintain the indicated mean effective pressure and the combustion phasing at a target value, and to keep the maximum pressure derivative under a limit to avoid engine damage in all the combustion modes by cyclically adapting the injection settings. Various tests were performed at steady-state conditions showing good abilities to fulfil the expected operating conditions but also to reject disturbances such as intake pressure or exhaust gas recirculation variations. Finally, the proposed control strategy was tested during a load transient resulting in a combustion switching-mode and the results exhibited the closed-loop potential for controlling such combustion concept.The author(s) disclosed receipt of the following finan-cial support for the research, authorship, and/or publi-cation of this article: The authors acknowledge the support of Spanish Ministerio de Economia, Industria y Competitividad through project TRA2016-78717-R. Alvin Barbier received a funding through the grant ACIF/2018/141 from the Generalitat Valenciana and the European Social Fund.Guardiola, C.; Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS. (2020). Closed-loop control of a dual-fuel engine working with different combustion modes using in-cylinder pressure feedback. International Journal of Engine Research. 21(3):484-496. https://doi.org/10.1177/1468087419835327S484496213Kusaka, J., Sueoka, M., Takada, K., Ohga, Y., Nagasaki, T., & Daisho, Y. (2005). A basic study on a urea-selective catalytic reduction system for a medium-duty diesel engine. International Journal of Engine Research, 6(1), 11-19. doi:10.1243/146808705x7310Hull, A., Golubkov, I., Kronberg, B., & van Stam, J. (2006). Alternative Fuel for a Standard Diesel Engine. International Journal of Engine Research, 7(1), 51-63. doi:10.1243/146808705x30549Sung, K., Kim, J., & Reitz, R. D. (2009). Experimental study of pollutant emission reduction for near-stoichiometric diesel combustion in a three-way catalyst. International Journal of Engine Research, 10(5), 349-357. doi:10.1243/14680874jer04109Johnson, T. V. (2009). Review of diesel emissions and control. International Journal of Engine Research, 10(5), 275-285. doi:10.1243/14680874jer04009Yun, H., & Reitz, R. D. (2005). Combustion optimization in the low-temperature diesel combustion regime. International Journal of Engine Research, 6(5), 513-524. doi:10.1243/146808705x30576Kook, S., Bae, C., & Kim, J. (2007). Diesel-fuelled homogeneous charge compression ignition engine with optimized premixing strategies. International Journal of Engine Research, 8(1), 127-137. doi:10.1243/14680874jer02506Ogawa, H., Azuma, K., & Miyamoto, N. (2007). Combustion control and operating range expansion in an homogeneous charge compression ignition engine with suppression of low-temperature oxidation by methanol: Influence of compression ratio and octane number of main fuel. International Journal of Engine Research, 8(1), 139-145. doi:10.1243/14680874jer01606Yao, M., Zheng, Z., & Liu, H. (2009). Progress and recent trends in homogeneous charge compression ignition (HCCI) engines. Progress in Energy and Combustion Science, 35(5), 398-437. doi:10.1016/j.pecs.2009.05.001Reitz, R. D. (2013). Directions in internal combustion engine research. Combustion and Flame, 160(1), 1-8. doi:10.1016/j.combustflame.2012.11.002Imtenan, S., Varman, M., Masjuki, H. H., Kalam, M. A., Sajjad, H., Arbab, M. I., & Rizwanul Fattah, I. M. (2014). Impact of low temperature combustion attaining strategies on diesel engine emissions for diesel and biodiesels: A review. Energy Conversion and Management, 80, 329-356. doi:10.1016/j.enconman.2014.01.020Paykani, A., Kakaee, A.-H., Rahnama, P., & Reitz, R. D. (2015). Progress and recent trends in reactivity-controlled compression ignition engines. International Journal of Engine Research, 17(5), 481-524. doi:10.1177/1468087415593013Hanson, R. M., Kokjohn, S. L., Splitter, D. A., & Reitz, R. D. (2010). An Experimental Investigation of Fuel Reactivity Controlled PCCI Combustion in a Heavy-Duty Engine. SAE International Journal of Engines, 3(1), 700-716. doi:10.4271/2010-01-0864Kokjohn, S. L., Hanson, R. M., Splitter, D. A., & Reitz, R. D. (2011). Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion. International Journal of Engine Research, 12(3), 209-226. doi:10.1177/1468087411401548Molina, S., García, A., Pastor, J. M., Belarte, E., & Balloul, I. (2015). Operating range extension of RCCI combustion concept from low to full load in a heavy-duty engine. Applied Energy, 143, 211-227. doi:10.1016/j.apenergy.2015.01.035Reitz, R. D., & Duraisamy, G. (2015). Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines. Progress in Energy and Combustion Science, 46, 12-71. doi:10.1016/j.pecs.2014.05.003Benajes, J., Molina, S., García, A., & Monsalve-Serrano, J. (2015). Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels. Energy Conversion and Management, 99, 193-209. doi:10.1016/j.enconman.2015.04.046Benajes, J., Pastor, J. V., García, A., & Boronat, 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.2016.08.023Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). Achieving clean and efficient engine operation up to full load by combining optimized RCCI and dual-fuel diesel-gasoline combustion strategies. Energy Conversion and Management, 136, 142-151. doi:10.1016/j.enconman.2017.01.010Shaver, G. M., Roelle, M. J., Caton, P. A., Kaahaaina, N. B., Ravi, N., Hathout, J.-P., … Gerdes, J. C. (2005). A physics-based approach to the control of homogeneous charge compression ignition engines with variable valve actuation. International Journal of Engine Research, 6(4), 361-375. doi:10.1243/146808705x30512Caton, P. A., Song, H. H., Kaahaaina, N. B., & Edwards, C. F. (2005). Residual-effected homogeneous charge compression ignition with delayed intake-valve closing at elevated compression ratio. International Journal of Engine Research, 6(4), 399-419. doi:10.1243/146808705x30431Dempsey, A. B., Walker, N. R., Gingrich, E., & Reitz, R. D. (2014). Comparison of Low Temperature Combustion Strategies for Advanced Compression Ignition Engines with a Focus on Controllability. Combustion Science and Technology, 186(2), 210-241. doi:10.1080/00102202.2013.858137Ritter, D., Andert, J., Abel, D., & Albin, T. (2017). Model-based control of gasoline-controlled auto-ignition. International Journal of Engine Research, 19(2), 189-201. doi:10.1177/1468087417717399Carlucci, A. P., Laforgia, D., Motz, S., Saracino, R., & Wenzel, S. P. (2014). Advanced closed loop combustion control of a LTC diesel engine based on in-cylinder pressure signals. Energy Conversion and Management, 77, 193-207. doi:10.1016/j.enconman.2013.08.054Ott, T., Zurbriggen, F., Onder, C., & Guzzella, L. (2013). Cylinder Individual Feedback Control of Combustion in a Dual Fuel Engine. IFAC Proceedings Volumes, 46(21), 600-605. doi:10.3182/20130904-4-jp-2042.00080Hanson, R., & Reitz, R. D. (2013). Transient RCCI Operation in a Light-Duty Multi-Cylinder Engine. SAE International Journal of Engines, 6(3), 1694-1705. doi:10.4271/2013-24-0050Indrajuana, A., Bekdemir, C., Luo, X., & Willems, F. (2016). Robust Multivariable Feedback Control of Natural Gas-Diesel RCCI Combustion. IFAC-PapersOnLine, 49(11), 217-222. doi:10.1016/j.ifacol.2016.08.033Luján, J. M., Galindo, J., Serrano, J. R., & Pla, B. (2008). A methodology to identify the intake charge cylinder-to-cylinder distribution in turbocharged direct injection Diesel engines. Measurement Science and Technology, 19(6), 065401. doi:10.1088/0957-0233/19/6/065401Payri, F., Broatch, A., Salavert, J. M., & Martín, J. (2010). Investigation of Diesel combustion using multiple injection strategies for idling after cold start of passenger-car engines. Experimental Thermal and Fluid Science, 34(7), 857-865. doi:10.1016/j.expthermflusci.2010.01.014Kokjohn, S. L., Hanson, R. M., Splitter, D. A., & Reitz, R. D. (2009). Experiments and Modeling of Dual-Fuel HCCI and PCCI Combustion Using In-Cylinder Fuel Blending. SAE International Journal of Engines, 2(2), 24-39. doi:10.4271/2009-01-2647Desantes, J. M., Benajes, J., García, A., & Monsalve-Serrano, J. (2014). The role of the in-cylinder gas temperature and oxygen concentration over low load reactivity controlled compression ignition combustion efficiency. Energy, 78, 854-868. doi:10.1016/j.energy.2014.10.08

On-Line Optimization of Dual-Fuel Combustion Operation by Extremum Seeking Techniques

[EN] Dual-fuel combustion engines have shown the potential to extend the operating range of Homogeneous Charge Compression Ignition (HCCI) by using several combustion modes, e.g. Reactivity Controlled Compression Ignition (RCCI) at low/medium load, and Partially Premixed Compression (PPC) at high load. In order to optimize the combustion mode operation, the respective sensitivity to the control inputs must be addressed. To this end, in this work the extremum seeking algorithm has been investigated. By definition, this technique allows to detect the control input authority over the system by perturbing its value by a known periodic signal. By analyzing the system response and calculating its gradient, the control input can be adjusted to reach optimal operation. This method has been applied to a dual-fuel engine under fully, highly and partially premixed conditions where the feedback information was provided by in-cylinder pressure and NOx sensors. The gasoline fraction and the injection timing were selected as control inputs and an extremum seeking controller was designed and verified to optimize brake efficiency by tracking the ideal combustion phasing and to reduce NOx emissions as well.The authors would like to recognize the financial support through Alvin Barbier's grant ACIF/2018/141, Programa Operativo del Fondo Social Europeo (FSE) de la Comunitat Valenciana 2014-2020. The authors also wish to thank Gabriel Alcantarilla for his assistance during the experimental campaign.Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS.; Guardiola, C. (2021). On-Line Optimization of Dual-Fuel Combustion Operation by Extremum Seeking Techniques. SAE International. 1-10. https://doi.org/10.4271/2021-01-051911

A combustion phasing control-oriented model applied to an RCCI engine

[EN] Low temperature combustions such as Reactivity Controlled Compression Ignition (RCCI) have been shown to be a promising way to reduce pollutants at the exhaust, i.e. NOx and soot emissions, and increase the thermal efficiency of future engines. However, such concepts are subject to substantial control sensitivity, e.g. combustion phasing, due to their lack of direct actuation for controlling the ignition of the mixture. This work investigates a control-oriented model based on physical equations aimed to predict the start of combustion and the crank angle of 50% fuel burnt (CA50). The model was developed for predicting the ignition using a modified knock integral model and a linear equation was used to estimate the burn duration between the start of combustion and the combustion phasing. The calibration and the validation of the model were performed using experimental data from a heavy-duty engine showing good results under transient operation.The authors acknowledge the support of Spanish Ministerio de Economia, Industria y Competitividad through project TRA2016-78717-R.Guardiola, C.; Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS. (2018). A combustion phasing control-oriented model applied to an RCCI engine. Elsevier. 119-124. https://doi.org/10.1016/j.ifacol.2018.10.02211912

Modeling combustion timing in an RCCI engine bymeans of a control oriented model

[EN] Reactivity controlled compression ignition (RCCI) engines as one of low temperature auto ignition combustion strategies have shown a good performance to reduce NO (x) and soot emission while increasing engine thermal efficiency. Combustion control of these types of engines is relatively complex because of their ignition type which makes it difficult to have a direct control on the start of the combustion. In this research, combustion phase of an RCCI engine was modeled with using a control-oriented method. The combustion properties such as start of the combustion, crank angle degree where 50 percent of the fuel is burnt(CA50) and the burn duration were modeled in this research. A modified knock integral model was used for start of combustion estimation. Using the effect of spontaneous front speed, burn duration was modeled where a mathematical model is developed; and Wiebe function is used to model CA50. Indicated mean effective pressure(IMEP) also estimated in this modeling. To validate the developed models, five experimental data sets from a heavy-duty RCCI engine were used. The results show the maximum mean errors of 1.7, 1.9 and 2.3 crank angle degree (CAD) for start of combustion, burn duration(BD) and the CA50, respectively and this quantity is 0.5 bar for IMEP in steady state condition. The transient condition of the engine operation was also investigated. The results and trends are promising in all characteristics of the combustion process especially in the modeling of the indicated mean effective pressure where the majority of the data have errors less than 1.5 bar.The authors acknowledge the support of Spanish Ministerio de Economia, Industria y Competitivad through project TRA2016-78717-R (AEI/FEDER, EU). Alvin Barbier participation was funded through grant ACIF/2018/141, Programa Operativo del Fondo Social Europeo (FSE) de la Comunitat Valenciana 2014-2020. Alireza Kakoee participation was funded through grants 43/3/298624 from Iran ministry of science, research and technology.Kakoee, A.; Bakhshan, Y.; Barbier, ARS.; Bares-Moreno, P.; Guardiola, C. (2020). Modeling combustion timing in an RCCI engine bymeans of a control oriented model. Control Engineering Practice. 97:1-15. https://doi.org/10.1016/j.conengprac.2020.1043211159

Analysis of Real-Driving Data Variability for Connected Vehicle Diagnostics

[EN] Connected vehicle paradigm allows the systematic recording of data, which may be made available for both on-board and cloud diagnostics functions. However, real-driving conditions may be highly dynamic, making the application of diagnostic methods cumbersome. This article analyzes the variability of real-world data coming from a mild hybrid vehicle at various levels (i.e., vehicle, powertrain and engine cycle). The results show that although non-steady, real-driving conditions can exhibit situations that could be leveraged to characterize the nominal operation of the vehicle over time and therefore ease the detection of faulty operation.This work has received support from the Spanish Agencia Estatal de InvestigaciOn through grant PID2019-108031RBC21/AEI/10.13039/501100011033 Cloud Diagnostics of Internal Combustion Engine Powerplants (CDPow).Barbier, ARS.; Salavert Fernández, JM.; Palau Salvador, CE.; Guardiola, C. (2022). Analysis of Real-Driving Data Variability for Connected Vehicle Diagnostics. Elsevier. 45-50. https://doi.org/10.1016/j.ifacol.2022.10.260455

An analysis of the in-cylinder pressure resonance excitation in internal combustion engines

[EN] This paper analyses the in-cylinder pressure oscillations in internal combustion engines, which are initiated by combustion and resonate during the expansion stroke. A specific mathematical tool, which takes into account the resonant frequency theory, has been developed to determine the resonance intensity evolution from the in cylinder pressure signal. Two engines, a conventional spark-ignited (SI) engin modified to perform homogeneous charge compression ignition (HCCI) combustion, and a conventional compression ignited (CI) engine, were used to analyse the resonance excitation in various combustion modes at different operating conditions. The new transformation has been used to characterize resonance in various combustion modes and a previous method developed by the authors to estimate the trapped mass was fed by such knowledge to improve its robustness and accuracy.Guardiola, C.; Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS. (2018). An analysis of the in-cylinder pressure resonance excitation in internal combustion engines. Applied Energy. 228:1272-1279. https://doi.org/10.1016/j.apenergy.2018.06.157S1272127922

Individual cylinder fuel blend estimation in a dual-fuel engine using an in-cylinder pressure based observer

[EN] Cylinder-to-cylinder combustion dispersion in internal combustion engines might be caused by various factors (e.g. manufacturing variations of the injectors or nozzle coking) which can result in an increase in pollutant emissions. When dealing with low temperature combustion concepts such as premixed dual-fuel, the system might suffer from an additional source of dispersion due to port fuel injection distribution. Conventional cylinder fuel concentration estimation is based on look-up tables previously calibrated and saved in the ECU. The aging and the fuel distribution characterization of the injectors are a challenging task when relying only on a single UEGO sensor placed at the exhaust. In-cylinder pressure sensors offer a powerful solution to evaluate the energy released by the fuel with one cycle resolution. The present work proposes to combine the information provided by such sensor together with conventional sensors, in this case air mass flow and lambda sensor, for estimating the fuel concentration and blending ratio entering each cylinder in a heavy-duty dual-fuel engine. A Kalman filter was designed to tackle the dynamics of the system, e.g. lambda sensor delay and port fuel distribution, and validated in both conventional diesel and dual-fuel combustion. The output of the filter was then used to update the injectors look-up table in order to cope with aging and possible bias over time.The authors would like to recognize the financial support through Alvin Barbier's grant ACIF/2018/141, Programa Operativo del Fondo Social Europeo (FSE) de la Comunitat Valenciana 2014-2020. The authors also wish to thank Gabriel Alcantarilla for his assistance during the experimental campaign.Guardiola, C.; Pla Moreno, B.; Bares-Moreno, P.; Barbier, ARS. (2021). Individual cylinder fuel blend estimation in a dual-fuel engine using an in-cylinder pressure based observer. Control Engineering Practice. 109:1-14. https://doi.org/10.1016/j.conengprac.2021.10476011410