This thesis discusses of the intake tract four-stroke ignition internal combustion engine and the filling efficiency and opportunities to increase this efficiency and consequently to optimize the course of torque and power at the specified serial engine. 3D model is the last point of this thesis.

No description available.

[ES] En la actualidad, el ambito del transporte mediante el uso de vehículo ligero sufre un gran cambio hacia la descarbonización. Cada vez más, las autoridades europeas restrigen las emisiones de gases de efectos invernaderos hacia la atmósfera emitidos por estos vehículos. Soluciones alternativas a la propulsión con energía fósil, como la implementación de vehículos eléctricos o híbridos, no está lo suficientemente desarrollada para sustituir a los motores de combustión interna alternativos (MCIA), debido a su todavía alto coste de producción y baja infrastructura para abastecer la demanda de energ ́ıa eléctrica. En este contexto, la transición hacia una movilidad sostenible y renovable sigue pasando por el aumento de la eficiencia y la reducción del consumo de combustible en motores de combustión interna. Una alternativa a la mejora de la eficiencia es la reducción de las pérdidas mecánicas por fricción, o en otras palabras, optimización de la tribología. La tribología en un MCIA lleva asociada aspectos mecánicos como la optimización de los acabados superficiales de los distintos componentes que conforman el motor y la optimización de propiedades física, químicas y reológicas del aceite que lo compone. Esta última solución presenta un alto ratio beneficio/coste, ya que su implementación no lleva asociada ninguna modificiación en el hardware y su implementación es directa. Uno de los objetivos de la Tesis Doctoral, es desarrollar un modelo 1D que contenga la información tribológica de un motor de combustión interna que no se puede obtener experimentalmente, que contribuya al entendimiento y optimización de las pérdidas mecánicas por fricción y que ahorre el coste experimental asociado a entender la tribología desde el punto de vista empírico. Estos parámetros van desde el espesor de película de aceite entre los componentes de un par rozante hasta la contribucción a la fricción de las componentes hidrodinámicas y de asperezas de cada elemento rozante. Adem ́as, se ha desarrollado un modelo cuasi estacionario para cuantificar la energ ́ıa disipada por fricción en un ciclo de conducción real y el consumo de combustible asociado al mismo. As ́ı pues, a través de este modelo, se implementan soluciones que pasan desde aceites optimizados reológicamente hasta acabados superficiales de baja rugosidad, entendiendo la fenomenología asociada a cada tecnología y aportando parámetros claves para la optimización de dicha solución. Finalmente, se estima el ahorro en términos de consumo de combustible que se puede alcanzar con estas soluciones implementadas mediante el modelo cuasi estacionario en condiciones de conducción real / [EN] Currently, the field of light-duty vehicle transport is undergoing a major shift towards decarbonisation. Increasingly, European authorities are restricting emissions of greenhouse gases into the atmosphere from these vehicles. Alternative solutions to fossil fuel propulsion, such as the implementation of electric or hybrid vehicles, are not sufficiently developed to replace internal combustion engine alternatives (ICEs), due to their still high production cost and low infrastructure to meet the demand for electric power. In this context, the transition towards sustainable and renewable mobility continues to be based on increasing efficiency and reducing fuel consumption in internal combustion engines. An alternative to improving efficiency is the reduction of mechanical frictional losses, or in other words, optimisation of tribology. Tribology in an MCIA is associated with mechanical aspects such as the optimisation of the surface finishes of the different components that make up the engine and the optimisation of the physical, chemical and rheological properties of the oil that makes up the engine. This last solution presents a high benefit/cost ratio, as its implementation does not involve any hardware modification and its implementation is straightforward. One of the objectives of the Doctoral Thesis is to develop a 1D model that contains the tribological information of an internal combustion engine that cannot be obtained experimentally, which contributes to the understanding and optimisation of mechanical friction losses and saves the experimental cost associated with understanding tribology from an empirical point of view. These parameters range from the oil film thickness between two tribological components to the contribution to friction of the hydrodynamic and roughness components of each friction element. In addition, a quasi-stationary model has been developed to quantify the energy dissipated by friction in a real driving cycle and the associated fuel consumption. Thus, through this model, solutions ranging from rheologically optimised oils to low roughness surface finishes are implemented, understanding the phenomenology associated with each technology and providing key parameters for the optimisation of the solution. Finally, the savings in terms of fuel consumption that can be achieved with these solutions implemented using the quasi-stationary model in real driving conditions are estimated. / [CA] Actualment, l’àmbit del transport mitjan ̧cant l’us de vehicles lleugers pateix un gran canvi cap a la descarbonització. Cada vegada m ́es, les autoritats europees restringeixen les emissions de gasos d’efecte hivernacle cap a l’atmosfera emesos per aquests vehicles. Les solucions alternatives a la propulsió amb energia fòssil, com la implementació de vehicles elèctrics o híbrids, no està prou desenvolupada per substituir els motors de combustió interna alternatius (MCIA), a causa del seu encara alt cost de producció i baixa infraestructura per abastir la demanda d’energia elèctrica. En aquest context, la transició cap a una mobilitat sostenible i renovable continua passant per l’augment de l’eficiència i la reducció del consum de combustible en motors de combustió interna. Una alternativa per a la millora de l’eficiència es la reducció de les pèrdues mecàniques per fricció, o en altres paraules, la optimització del comportament tribològic del motor. La tribologia en un MCIA porta associada aspectes mecànics com ara l’optimització dels acabats superficials dels diferents components que conformen el motor i l’optimització de propietats física, químiques i reològiques de l’oli que va a emprar. Aquesta ́ultima solució presenta una alta ratio benefici/cost, ja que la seva implementació no porta associada cap modificació de la màquina i la seva implementació ́es directa. Un dels objectius de la Tesi Doctoral es desenvolupar un model 1D que permet obtindré la informació tribològica d’un motor de combustió interna que no es pot obtenir experimentalment, que contribueixi a l’enteniment i l’optimització de les pèrdues mecàniques per fricció i que estalvi ̈ı el cost experimental associat a entendre la tribologia des del punt de vista empíric. Aquests paràmetres van des de l’espessor de pel·lícula d’oli entre els components d’un parell tribològic fins a la contribució a la fricció dels components amb regim hidrodinàmic i de la rugositat de cada element. A més, s’ha desenvolupat un model gairebé estacionari per quantificar l’energia dissipada per fricció en un cicle de conducció real i el consum de combustible associat. Així, a traves d’aquest model, s’implementen solucions que passen des d’olis optimitzats reològicament fins a acabats superficials de baixa rugositat, entenent la fenomenologia associada a cada tecnologia i aportant paràmetres clau per optimitzar aquesta solució. Finalment, s’estima l’estalvi en termes de consum de combustible que es pot assolir amb aquestes solucions implementades mitjan ̧cant el model quasi estacionari en condicions de conducció real. / Agradezco al programa de Formación de Profesorado Universitario del Ministerio de Ciencia, Innovación y Universidades por soportar financieramiente mis estudios doctorales (FPU18/02116) y la estancia de investigación que contribuyó a aumentar los conocimientos desarrollados en la presente tesis doctoral (EST21/00451). / Jiménez Reyes, AJ. (2022). Assessment and Optimization of Friction Losses and Mechanical Efficiency in Internal Combustion Engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188986

Rocket propulsion using the hybrid-propellant scheme is a technology that offers much promise in applications where high-performance liquid rocket engines are deemed too complex and solid rocket motors are considered to lack performance or safety. However, despite extensive research, there is still a lack of knowledge in the theoretical aspects of hybrid rocketry, especially in the area of fuel-oxidizer mixing and fuel regression rate. This lack of a good theoretical model makes the implementation of good, practical solutions and mature, well-functioning designs more diffcult. This disadvantages the hybrid rocket engine when compared to liquid rocket engines or solid rocket motors.In this study, a hybrid rocket engine burning polymethyl methacrylate (PMMA) with compressed air has been designed to the point of a preliminary design defnition. PMMA is a transparent material, and this has been utilized to create a transparent-chamber rocket engine where engine processes can be studied with various optical methods withoutinterrupting or disturbing the operation of the engine. The function of hybrid rocket engines, the technological solutions involved in designing working hybrid rocket engines and the constituent parts of hybrid rocket engines have been studied. The nature of the trade-offs between performance and simplicity that occur when designing a rocket engine are also studied, with a focus on maximizing simplicity, safety and minimizing expenses, while still designing an engine that fulfills basic requirements. The results include a design defnition with a preliminary user’s guide, a feasibility study, and a summary of the results of the hybrid rocket performance model that was used to determine appropriate design parameters.

<p> One primary focus on internal combustion engines is that these engines create multiple harmful exhaust gases that can cause damage to the environment. There are a number of advanced strategies that are currently being investigated to help reduce the amount of these harmful emissions that are emitted from IC engines. One such method of reducing harmful emission gases focuses on the three-way-catalyst. A three-way-catalyst (TWC) is an exhaust emission control device that is designed in such a way to take harmful exhaust gases and convert them into less harmful gases through various chemical reactions within the TWC. To help further the reduction of these harmful gases in the TWC, a novel two-loop control and estimation strategy is used. This control and estimation strategy involves the use of two loops with an inner-loop controller, outer-loop robust controller, and an estimator in the outer-loop. The estimator consists of a TWC model and an extended Kalman filter which is used to estimate the fractional oxidation state (FOS) of the TWC. This estimated FOS is then used by the robust controller, along with other parameters, to produce a desired engine lambda reference signal, λup. This desired lambda signal is then used by the inner-loop controller to control the engine lambda. Accurate control of lambda is important because the air-fuel-ratio range for a TWC to effectively achieve oxidation and reduction simultaneously is extremely narrow. Another primary focus in the field of internal combustion engines is designing and tuning advanced models within GT-Power that can accurately predict what will happen when running an actual engine. Designing, troubleshooting, and testing a GT-Power model is an extensive but rewarding process. Creating an accurate engine model can not only provide one with primary engine data that is also measurable in a test cell, but can also provide insight into some of the intricate processes and nature of the engine that are difficult or impossible to physically measure. Cummins has an extensive process of tuning GT-Power engine models. This process include items such as initial model calibrations, model discretizations, turbocharger tunings, and other items. Some of these processes are used to calibrate both Cummins Power Systems Business Unit engines as well as a Purdue B6.7N natural gas engine. </p>