automatic calibration of control parameters based on merit function spectral analysis

Abstract The number of actuations influencing the combustion is increasing, and, as a consequence, the calibration of control parameters is becoming challenging. One of the most effective factors influencing performance and efficiency is the combustion phasing: for gasoline engines control variables such as Spark Advance (SA), Air-to-Fuel Ratio (AFR), Variable Valve Timing (VVT), Exhaust Gas Recirculation (EGR) are mostly used to set the combustion phasing. The optimal control setting can be chosen according to a cost function, taking into account performance indicators, such as Indicated Mean Effective Pressure (IMEP), Brake Specific Fuel Consumption (BSFC), pollutant emissions, or other indexes inherent to reliability issues, such as exhaust gas temperature, or knock intensity. The paper proposes the use of the extremum seeking approach during the calibration process. The main idea consists in changing the values of each control parameter at the same time, identifying its effect on the monitored cost function, allowing to shift automatically the control setting towards the optimum solution throughout the calibration procedure. Obviously, the nodal point is to establish how the various control parameters affect the monitored cost function and to determine the direction of the required variation, in order to approach the optimum. This task is carried out by means of a spectral analysis of the cost function: each control variable is varied according to a sine wave, thus its effect on the cost function can be determined by evaluating the amplitude of the Fast Fourier Transform (FFT) of the cost function, for the given excitation frequency. The FFT amplitude is representative of the cost function sensitivity to the control variable variations, while the phase can be used to assess the direction of the variation that must be applied to the control settings in order to approach the optimum configuration. Each control parameter is excited with a different frequency, thus it is possible to recognize the effect of a single parameter by analyzing the spectrum of the cost function for the given excitation frequency. The methodology has been applied to data referring to a PFI engine, trying to maximize IMEP, while limiting the knock intensity and exhaust gas temperature, using SA and AFR as control variables. The approach proved to be efficient in reaching the optimum control setting, showing that the optimal setting can be achieved rapidly and consistently

Cycle-to-cycle combustion variability modelling in spark ignited engines for control purposes

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/10.1177/1468087419885754.[EN] 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.The authors appreciate the technical support and the clues given by J. Israel Sanchez for the model development and also acknowledge the support of Spanish Ministerio de Economia, Industria y Competitividad through project TRA2016-78717-R.Pla Moreno, B.; De La Morena, J.; Bares-Moreno, P.; Jimenez, IA. (2020). Cycle-to-cycle combustion variability modelling in spark ignited engines for control purposes. International Journal of Engine Research. 21(8):1398-1411. https://doi.org/10.1177/1468087419885754S13981411218Wang, S., Prucka, R., Zhu, Q., Prucka, M., & Dourra, H. (2016). A Real-Time Model for Spark Ignition Engine Combustion Phasing Prediction. SAE International Journal of Engines, 9(2), 1180-1190. doi:10.4271/2016-01-0819Kim, N., Ko, I., & Min, K. (2018). Development of a zero-dimensional turbulence model for a spark ignition engine. International Journal of Engine Research, 20(4), 441-451. doi:10.1177/1468087418760406Wang, S., Zhu, Q., Prucka, R., Prucka, M., & Dourra, H. (2015). Input Adaptation for Control Oriented Physics-Based SI Engine Combustion Models Based on Cylinder Pressure Feedback. SAE International Journal of Engines, 8(4), 1463-1471. doi:10.4271/2015-01-0877Zhen, X., Wang, Y., Xu, S., Zhu, Y., Tao, C., Xu, T., & Song, M. (2012). The engine knock analysis – An overview. Applied Energy, 92, 628-636. doi:10.1016/j.apenergy.2011.11.079Bares, P., Selmanaj, D., Guardiola, C., & Onder, C. (2018). Knock probability estimation through an in-cylinder temperature model with exogenous noise. Mechanical Systems and Signal Processing, 98, 756-769. doi:10.1016/j.ymssp.2017.05.033Zhang, Y., Shen, X., Wu, Y., & Shen, T. (2019). On-board knock probability map learning–based spark advance control for combustion engines. International Journal of Engine Research, 20(10), 1073-1088. doi:10.1177/1468087419858026Spelina, J. M., Peyton Jones, J. C., & Frey, J. (2014). Stochastic simulation and analysis of a classical knock controller. International Journal of Engine Research, 16(3), 461-473. doi:10.1177/1468087414551073Neumann, D., Jörg, C., Peschke, N., Schaub, J., & Schnorbus, T. (2017). Real-time capable simulation of diesel combustion processes for HiL applications. International Journal of Engine Research, 19(2), 214-229. doi:10.1177/1468087417726226Pipitone, E. (2008). A Comparison Between Combustion Phase Indicators for Optimal Spark Timing. Journal of Engineering for Gas Turbines and Power, 130(5). doi:10.1115/1.2939012Bares, P., Selmanaj, D., Guardiola, C., & Onder, C. (2018). A new knock event definition for knock detection and control optimization. Applied Thermal Engineering, 131, 80-88. doi:10.1016/j.applthermaleng.2017.11.138Peyton Jones, J. C., Spelina, J. M., & Frey, J. (2013). Optimizing knock thresholds for improved knock control. International Journal of Engine Research, 15(1), 123-132. doi:10.1177/1468087413482321Emiliano, P. (2014). Spark Ignition Feedback Control by Means of Combustion Phase Indicators on Steady and Transient Operation. Journal of Dynamic Systems, Measurement, and Control, 136(5). doi:10.1115/1.4026966Zhu, Q., Prucka, R., Wang, S., Prucka, M., & Dourra, H. (2016). Model-Based Optimal Combustion Phasing Control Strategy for Spark Ignition Engines. SAE International Journal of Engines, 9(2), 1170-1179. doi:10.4271/2016-01-0818Zhang, Y., & Shen, T. (2017). Cylinder pressure based combustion phase optimization and control in spark-ignited engines. Control Theory and Technology, 15(2), 83-91. doi:10.1007/s11768-017-6175-1Zhang, Y., Shen, X., & Shen, T. (2018). A survey on online learning and optimization for spark advance control of SI engines. Science China Information Sciences, 61(7). doi:10.1007/s11432-017-9377-7Corti, E., Forte, C., Mancini, G., & Moro, D. (2014). Automatic Combustion Phase Calibration With Extremum Seeking Approach. Journal of Engineering for Gas Turbines and Power, 136(9). doi:10.1115/1.4027188Corti, E., Cerofolini, A., Cavina, N., Forte, C., Mancini, G., Moro, D., … Ravaglioli, V. (2014). Automatic Calibration of Control Parameters based on Merit Function Spectral Analysis. Energy Procedia, 45, 919-928. doi:10.1016/j.egypro.2014.01.097Popovic, D., Jankovic, M., Magner, S., & Teel, A. R. (2006). Extremum seeking methods for optimization of variable cam timing engine operation. IEEE Transactions on Control Systems Technology, 14(3), 398-407. doi:10.1109/tcst.2005.863660Hellstrom, E., Lee, D., Jiang, L., Stefanopoulou, A. G., & Yilmaz, H. (2013). On-Board Calibration of Spark Timing by Extremum Seeking for Flex-Fuel Engines. IEEE Transactions on Control Systems Technology, 21(6), 2273-2279. doi:10.1109/tcst.2012.2236093Pera, C., Chevillard, S., & Reveillon, J. (2013). Effects of residual burnt gas heterogeneity on early flame propagation and on cyclic variability in spark-ignited engines. Combustion and Flame, 160(6), 1020-1032. doi:10.1016/j.combustflame.2013.01.009Zhao, L., Moiz, A. A., Som, S., Fogla, N., Bybee, M., Wahiduzzaman, S., … Kodavasal, J. (2017). Examining the role of flame topologies and in-cylinder flow fields on cyclic variability in spark-ignited engines using large-eddy simulation. International Journal of Engine Research, 19(8), 886-904. doi:10.1177/1468087417732447Pera, C., Knop, V., & Reveillon, J. (2015). Influence of flow and ignition fluctuations on cycle-to-cycle variations in early flame kernel growth. Proceedings of the Combustion Institute, 35(3), 2897-2905. doi:10.1016/j.proci.2014.07.037Schiffmann, P., Reuss, D. L., & Sick, V. (2017). Empirical investigation of spark-ignited flame-initiation cycle-to-cycle variability in a homogeneous charge reciprocating engine. International Journal of Engine Research, 19(5), 491-508. doi:10.1177/1468087417720558Galloni, E. (2009). Analyses about parameters that affect cyclic variation in a spark ignition engine. Applied Thermal Engineering, 29(5-6), 1131-1137. doi:10.1016/j.applthermaleng.2008.06.001Tamaki, S., Sakayanagi, Y., Sekiguchi, K., Ibuki, T., Tahara, K., & Sampei, M. (2014). On-line Feedforward Map Generation for Engine Ignition Timing Control. IFAC Proceedings Volumes, 47(3), 5691-5696. doi:10.3182/20140824-6-za-1003.01886Zhang, Y., & Shen, T. (2018). Combustion Variation Feedback Control Approach for Multi-cylinder Spark Ignition Engines. IFAC-PapersOnLine, 51(31), 105-110. doi:10.1016/j.ifacol.2018.10.020Corti, E., & Forte, C. (2011). Spark Advance Real-Time Optimization Based on Combustion Analysis. Journal of Engineering for Gas Turbines and Power, 133(9). doi:10.1115/1.4002919Gao, J., Wu, Y., & Shen, T. (2016). Experimental comparisons of hypothesis test and moving average based combustion phase controllers. ISA Transactions, 65, 504-515. doi:10.1016/j.isatra.2016.09.003Gao, J., Wu, Y., & Shen, T. (2017). A statistical combustion phase control approach of SI engines. Mechanical Systems and Signal Processing, 85, 218-235. doi:10.1016/j.ymssp.2016.08.007Lee, D., Jiang, L., Yilmaz, H., & Stefanopoulou, A. G. (2010). Preliminary Results on Optimal Variable Valve Timing and Spark Timing Control via Extremum Seeking. IFAC Proceedings Volumes, 43(18), 377-384. doi:10.3182/20100913-3-us-2015.00038Di Mauro, A., Chen, H., & Sick, V. (2019). Neural network prediction of cycle-to-cycle power variability in a spark-ignited internal combustion engine. Proceedings of the Combustion Institute, 37(4), 4937-4944. doi:10.1016/j.proci.2018.08.058Lapuerta, M., Armas, O., & Hernández, J. J. (1999). Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas. Applied Thermal Engineering, 19(5), 513-529. doi:10.1016/s1359-4311(98)00075-1Ceviz, M. A., & Kaymaz, İ. (2005). Temperature and air–fuel ratio dependent specific heat ratio functions for lean burned and unburned mixture. Energy Conversion and Management, 46(15-16), 2387-2404. doi:10.1016/j.enconman.2004.12.009Guardiola, C., Triantopoulos, V., Bares, P., Bohac, S., & Stefanopoulou, A. (2016). Simultaneous Estimation of Intake and Residual Mass Using In-Cylinder Pressure in an Engine with Negative Valve Overlap. IFAC-PapersOnLine, 49(11), 461-468. doi:10.1016/j.ifacol.2016.08.068Wang, S., Prucka, R., Prucka, M., & Dourra, H. (2014). Control-oriented residual gas mass prediction for spark ignition engines. International Journal of Engine Research, 16(7), 897-907. doi:10.1177/1468087414555732Keck, J. C. (1982). Turbulent flame structure and speed in spark-ignition engines. Symposium (International) on Combustion, 19(1), 1451-1466. doi:10.1016/s0082-0784(82)80322-

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

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

Adaptive calibration of Diesel engine injection for minimising fuel consumption with constrained NOx emissions in actual driving missions

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/10.1177/1468087420918800[EN] This article proposes a method for fuel minimisation of a Diesel engine with constrained NOx emission in actual driving mission. Specifically, the methodology involves three developments: The first is a driving cycle prediction tool which is based on the space-variant transition probability matrix obtained from an actual vehicle speed dataset. Then, a vehicle and an engine model is developed to predict the engine performance depending on the calibration for the estimated driving cycle. Finally, a controller is proposed which adapts the start-of-injection calibration map to fulfil the NOx emission constraint while minimising the fuel consumption. The calibration is adapted during a predefined time window based on the predicted engine performance on the estimated cycle and the difference between the actual and the constraint on engine NOx emissions. The method assessment was done experimentally in the engine test set-up. The engine performace using the method is compared with the state-of-the-art static calibration method for different NOx emission limits on real driving cycles. The online implementation of the method shows that the fuel consumption can be reduced by 3%-4% while staying within the emission limits, indicating that the estimation method is able to capture the main driving cycle characterstics.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 Ministrrio de Economia, Industria y Competitivad through project TRA2016-78717-R.Luján, JM.; Pla Moreno, B.; Bares-Moreno, P.; Pandey, V. (2021). Adaptive calibration of Diesel engine injection for minimising fuel consumption with constrained NOx emissions in actual driving missions. International Journal of Engine Research. 22(6):1896-1905. https://doi.org/10.1177/1468087420918800S1896190522

A Study Model Predictive Control for Spark Ignition Engine Management and Testing

Pressure to improve spark-ignition (SI) engine fuel economy has driven thedevelopment and integration of many control actuators, creating complex controlsystems. Integration of a high number of control actuators into traditional map basedcontrollers creates tremendous challenges since each actuator exponentially increasescalibration time and investment. Model Predictive Control (MPC) strategies have thepotential to better manage this high complexity since they provide near-optimal controlactions based on system models. This research work focuses on investigating somepractical issues of applying MPC with SI engine control and testing.Starting from one dimensional combustion phasing control using spark timing(SPKT), this dissertation discusses challenges of computing the optimal control actionswith complex engine models. A nonlinear optimization is formulated to compute thedesired spark timing in real time, while considering knock and combustion variationconstraints. Three numerical approaches are proposed to directly utilize complex high-fidelity combustion models to find the optimal SPKT. A model based combustionphasing estimator that considers the influence of cycle-by-cycle combustion variations isalso integrated into the control system, making feedback and adaption functions possible.An MPC based engine management system with a higher number of controldimensions is also investigated. The control objective is manipulating throttle, externalEGR valve and SPKT to provide demanded torque (IMEP) output with minimum fuelconsumption. A cascaded control structure is introduced to simplify the formulation and solution of the MPC problem that solves for desired control actions. Sequential quadratic programming (SQP) MPC is applied to solve the nonlinear optimization problem in real time. A real-time linearization technique is used to formulate the sub-QP problems with the complex high dimensional engine system. Techniques to simplify the formulation of SQP and improve its convergence performance are also discussed in the context of tracking MPC. Strategies to accelerate online quadratic programming (QP) are explored. It is proposed to use pattern recognition techniques to “warm-start” active set QP algorithms for general linear MPC applications. The proposed linear time varying (LTV) MPC is used in Engine-in-Loop (EIL) testing to mimic the pedal actuations of human drivers who foresee the incoming traffic conditions. For SQP applications, the MPC is initialized with optimal control actions predicted by an ANN. Both proposed MPC methods significantly reduce execution time with minimal additional memory requirement

Development of Combustion Indicators for Control of Multi-Fuel Engines Based on New Combustion Concepts

[ES] Debido a las regulaciones en materia de emisiones y CO2 la industria automotriz a desarrollado diferentes tecnologías innovadoras. Estas tecnologías incluyen combustibles alternativos y nuevos modos de combustión, entre otros. De aquí surge la necesidad del desarrollo de nuevos métodos para el control de la combustión en estas condiciones mencionadas. Por este motivo, en este trabajo se han desarrollado diferentes modelos e indicadores orientados al diagnóstico y control de la combustión tanto en condiciones normales como anormales. Para los casos de combustión normal, se ha desarrollado un modelo de combustión, cuyo objetivo es estimar la media de la evolución de la fracción de la masa quemada y la presión dentro del cilindro. Se implementó un observador, basado en la señal de knock, con la finalidad de mejorar la estimación en condiciones transitorias y poder aplicar así el modelo a diferentes tipos de combustibles. También se presenta un modelo de variabilidad cíclica, en el cual, a partir del modelo de combustión, se propaga una distribución en dos de los parámetros de dicho modelo. Ambos modelos han sido aplicados para un motor de encendido provocado y un motor de combustión de encendido por chorro turbulento. En los casos de combustión anormal, se ha incluido un análisis de la resonancia dentro de la cámara de combustión, en donde también se desarrollaron dos modelos capaces de estimar la evolución de la resonancia. Estos modelos, tanto para condiciones normales como anormales, se utilizaron para el diagnóstico de la combustión. Por una parte, para la detección de knock, en donde tres estrategias de detección de knock fueron desarrolladas: dos basadas en el sensor de presión en cámara y una en el sensor de knock. Por otra parte, se realizó una aplicación de un modelo de resonancia para la mejora de la estimación de la masa atrapada a partir de la resonancia. Finalmente, para mostrar el potencial de los modelos de diagnóstico, dos aplicaciones a control se desarrollaron: una para el control de knock a través de la actuación de la chispa, y otra para el control de gases residuales, a través de la actuación de la distribución variable, realizando paralelamente una optimización de la combustión a través de la actuación de la chispa.[CA] Impulsada per les regulacions en matèria d'emissions i CO2 la indústria automotriu a desenvolupat diferents tecnologies inovadore. Aquestes tecnologies inclouen combustibles alternatius i nous modes de combustió, entre altres. D'ací sorgix la necessitat posar en pràctica nous mètodes per al control de la combustió. En aquest context, el present trevall proposa diferents models i indicadors orientats al diagnòstic i control de la combustió tant en condicions normals com anormals. Per als casos de combustió normal, es proposa un model de combustió, l'objectiu del qual és estimar la mitjana de l'evolució de la fracció de la massa cremada i la pressió dins del cilindre. Es va implementar un observador, basat en la senyal de knock, amb la finalitat de millorar l'estimació en condicions transitòries i poder aplicar així el model a diferents tipus de combustibles. També es presenta un model de variabilitat cíclica, en el qual, a partir del model de combustió, es propaga una distribució en dos dels parametres del dit model. Ambdós models han sigut aplicats a un motor d'encesa provocada i un motor de combustió d'encesa per doll turbulent. Als casos de combustió anormal, s'ha inclos un anàlisi de la ressonància dins de la cambra de combustió, on també es van desenvolupar dos models capaços d'estimar l'evolució de la ressonància. Aquests models, tant per a condicions normals com anormals, s'utilitzen per al diagnòstic de la combustió. Per una part, per a la detecció de knock, on tres estratègies de detecció de knock s'han desenvolupat: dues basades en el sensor de pressió a la cambra de combustió i una altra basada en el sensor de knock. Per altra part, es va realitzar una aplicació d'un model de ressonància per a la millora de l'estimació de la massa atrapada a partir de la ressonància. Finalment, per a mostrar el potencial dels models de diagnòstic, dos aplicacions de control es van desenvolupar: una per al control de knock a través de l'actuació de l'espurna, i una altra per al control de gasos residuals, a través de l'actuació de la distribució variable, realitzant paral·lelament una optimització de la combustió a través de l'actuació de l'espurna.[EN] The need to satisfy emissions and CO2 regulations is pushing the automotive industry to develop different innovative technologies. These technologies include alternative fuels and new modes of combustion, among others. Therefore, the need for the development of new methods for combustion control in these mentioned conditions arises. For this reason, in this work different models and indicators have been developed aimed at the diagnosis and control of combustion in both normal and abnormal conditions. For normal combustion cases, a combustion model has been developed, the objective of this model is to estimate the mean of evolution of the mass fraction burned and the in-cylinder pressure. An observer had been implemented, based on knock sensor signal, in order to improve the estimation in transient conditions and also to be able to make use of the model with different fuels. A cyclic variability model is also presented, where from the combustion model, a probability distribution is propagated over two of the parameters of such model. Both models had been applied for a spark ignition engine and a turbulent jet ignition combustion engine. For the abnormal combustion cases, an analysis of the resonance within the combustion chamber had been included, where two models capable of estimating the evolution of the resonance were also developed. These models, for both normal and abnormal conditions, were used for the diagnosis of combustion: on the one hand, for knock recognition, where three knock detection strategies were developed: two based on the in-cylinder pressure sensor and one on the knock sensor. On the other hand, an application of a resonance model was carried out in order to improve the estimation of the trapped mass from the resonance excitation. Finally, to show the potential of such models and applications, two control strategies were developed: one for the control of knock through the actuation of the spark advance, and a second for the control of residual gases, through the actuation of the variable valve timing, while optimizing the combustion through the actuation of the spark advance.El trabajo desarrollado en esta tesis ha sido posible gracias a la financiación de la Generalitat Valenciana y el fondo social europeo a través de la beca 132 GRISO- LIAP/2018/132 y BEFPI/2021/042.Jiménez, IA. (2022). Development of Combustion Indicators for Control of Multi-Fuel Engines Based on New Combustion Concepts [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181561TESI

CLEAN COMBUSTION CONTROL IN A COMPRESSION IGNITION ENGINE

The primary objective of this dissertation is to develop combustion control strategies, that can reduce the thermal efficiency penalty associated with clean combustion in modern compression ignition engines. The clean combustion targets of simultaneously low oxides of nitrogen (NOX) and smoke emissions are selected as the platforms for demonstrating the dynamic control strategies on a single cylinder research engine. First, parametric analyses, including exhaust gas recirculation (EGR) calculations, are performed using a zero-dimensional engine cycle simulation model. Thereafter, two combustion strategies are experimentally investigated, namely the single-shot diesel strategy and the dual-fuel strategy. The single-shot diesel combustion strategy employs a single direct injection of diesel with the use of moderate levels of EGR. In the dual-fuel combustion strategy, port injection of ethanol is utilized in addition to the direct injection of diesel and the application of EGR. The results of parametric analyses and engine experiments provide guidelines for the development of a systematic control strategy. Closed-loop combustion control systems are implemented for regulating the fuel injection commands, by which the combustion phasing is effectively controlled on a cycle-by-cycle basis in both the diesel and dual-fuel combustion strategies. The fuel injection control is integrated into the systematic control strategy for simultaneously controlling the air and fuel systems. The intake boost pressures, EGR rates, and fuelling strategies are dynamically selected, depending on the engine load level. By implementing the systematic control, both the NOX and smoke targets are achieved over a wide engine load range, while retaining the thermal efficiency of conventional diesel combustion

Model-Based Control of Gasoline Partially Premixed Combustion

Partially Premixed Combustion (PPC) is an internal combustion engine concept that aims to yield low NOx and soot emission levels together with high engine efficiency. PPC belongs to the class of low temperature combustion concepts where the ignition delay is prolonged in order to promote the air-fuel-mixture homogeneity in the combustion chamber at the start of combustion. A more homogeneous combustion process in combination with high exhaust-gas recirculation (EGR) ratios gives lower combustion temperatures and thus decreased NOx and soot formation. The ignition delay is mainly controlled by temperature, gas-mixture composition, fuel type and fuel-injection timing. It has been shown that PPC run on gasoline fuel can provide sufficient ignition delays in conventional compression-ignition engines. The PPC concept differs from conventional direct-injection diesel combustion because of its increased sensitivity to intake conditions, its decreased combustion-phasing controllability and its high pressure-rise rates related to premixed combustion, this puts higher demands on the engine control system. This thesis investigates model predictive control (MPC) of PPC with the use of in-cylinder pressure sensors. Online heat-release analysis is used for the detection of the combustion phasing and the ignition delay that function as combustion-feedback signals. It is shown that the heat-release analysis could be automatically calibrated using nonlinear estimation methods, the heat-release analysis is also a central part of a presented online pressure-prediction method which can be used for combustion-timing optimization. Low-order autoignition models are studied and compared for the purpose of model-based control of the ignition-delay, the results show that simple mathematical models are sufficient when anipulating the intake-manifold conditions. The results also show that the relation between the injection timing and the ignition delay is not completely captured by these types of models when the injection timing is close to top-dead-center. Simultaneous control of the ignition delay and the combustion phasing using a dual-path EGR system, thermal management and fuel injection timings is studied and a control design is presented and evaluated experimentally. Closed-loop control of the pressure-rise rate using a pilot fuel injection is also studied and the multiple fuel-injection properties are characterized experimentally. Experiments show that the main-fuel injection controls the combustion timing and that the pilot-injection fuel could be used to decrease the main fuel injection ignition delay and thus the pressure-rise rate. The controllability of the pressure-rise rate was shown to be higher when the pilot injection was located close to the main-fuel injection. A pressure-rise-rate controller is presented and evaluated experimentally. All experiments presented in this thesis were conducted on a Scania D13 production engine with a modified gas-exchange system, the fuel used was a mixture of 80 % gasoline and 20 % N-heptane (by volume)