The aim of the thesis is to derive a mathematical model of the engine and driveline in a passenger car, capable of describing the wheel speed disturbances related to the engine and driveline. The thesis is conducted in order to improve the disturbance cancelation algorithm in the indirect tire pressure monitoring system, TPI developed by NIRA Dynamics AB. The model consists of two parts, the model of the engine and the model of the driveline. The engine model uses an analytical cylinder pressure model capable of describing petrol and diesel engines. The model is a function of the crank angle, manifold pressure, manifold temperature and spark timing. The output is the pressure in the cylinder. This pressure is then used to calculate the torque generated on the crankshaft when the pressure acts on the piston. This torque is then applied in the driveline model. Both a two wheel and a four wheel driveline model are presented and they consist of a series of masses and dampers connected to each other with stiff springs. The result is a 14 and 19 degrees of freedom system of differential equations respectively. The model is then validated using measurements collected at LiU during two experiments. Measurements where conducted of the cylinder pressure of a four cylinder petrol engine and on the wheel speed of two different cars when driven in a test rig. The validation against this data is satisfactory and the simulations and measurements show good correlation. The model is then finally used to examine wheels speed disturbance phenomenon discovered in the huge database of test drives available at NIRA Dynamics AB. The effects of the drivelines natural frequencies are investigated and so is the difference between the disturbances on the wheel speed for a petrol and diesel engine. The main reasons for the different disturbance levels on the front and rear wheels in a four wheel drive are also discussed.

Simulating the translatory motion of a vehicle during a gear shift gives a good basis to evaluate performance and comfort of a gear shift. This evaluation can be used for gear shifting strategy in an automatic transmission. A model of a diesel engine and it's electronic control system is developed to capture the engines behaviour in a vehicle simulation environment. The modelled quantities are brake torque, fuel consumption and exhaust gas temperature and are based on engine speed and pedal position. In order to describe these outputs the inlet air flow and boost pressure are also modelled and used as inner variables. The model is intended to be implemented on board a vehicle in a control unit which has limited computational performance. To keep the model as computationally efficient as possible the model basically consists of look-up tables and polynomials. First order systems are used to describe the dynamics of air flow and exhaust temperature. The outputs enables gear shift optimization over three variables, torque for vehicle acceleration, fuel consumption for efficiency and exhaust temperature to maintain high efficiency in the exhaust after treatment system. The engine model captures the low frequent dynamics of the modelled quantities in the closed loop of the engine and it's electronic control system. The model only consists of three states, one for the pressure build up in the intake manifold and two states for modelling the exhaust temperature. The model is compared to measured data from a engine test cell and the mean absolute relative error are lower than 6.8%, 7.8% and 5.8% for brake torque, fuel consumption and exhaust gas temperature respectively. These results are considered good given the simplicity of the model.

The state-of-the-art traffic simulation packages model traffic on a microscopic level. This includes the use of several sets of models that dictate how traffic moves within a transportation network. These models include car-following, gap acceptance, lane-changing and route choice models. The aim of this thesis is to improve the treatment of vehicle dynamics in traffic simulation and, as a result, special attention was paid to car-following models. These models were highlighted because they are largely responsible for capturing a vehicle’s motion and its relevant dynamics in traffic simulation. In order to improve the treatment of vehicle dynamics in traffic simulation, a Dynamic-Interactive-Vehicle (DIV) model was developed. This vehicle model is calibrated with the use of essential vehicle performance specifications that are responsible for the movement of a vehicle in a transportation network. After the calibration process the model is able to accept three inputs from a driver – gas pedal, brake pedal and steering wheel positions. The model then outputs the corresponding longitudinal and latitudinal values which represent the movement of a vehicle along a roadway. The vehicle model will also account for most of the dominant external forces that affect an automobile’s performance along a roadway. This thesis will validate the proposed model by comparing its output from a few performance tests with the performance test results of three passenger cars. The DIV model was validated by comparing the acceleration, braking and steering performance test results of three passenger cars with the output from the DIV model upon performing similar tests. It was found that the DIV model was successful at replicating the two-dimensional vehicle motion.

[EN] Current challenges in research and development of powertrains demand new computational tools capable of simulating vehicle operation under very diverse conditions. This is due, among other reasons, to new homologation standards in the automotive sector requiring compliance of exhaust emissions regulations under any possible driving condition on the road. Global engine or vehicle models provide many advantages to engineers because they allow to reproduce the entire system under study, considering the physical processes that take place in different components and the interactions among them. This thesis aims to enable the modeling of heat transfer processes in a complete engine simulation tool developed at CMT-Motores Térmicos research institute. This 0D/1D simulation tool is called Virtual Engine Model (VEMOD). The development of heat transfer models comprises the engine block and the ancillary systems. The model of heat transfer in the engine block deals with the central problem of in-cylinder convection by means of a combination of experimental research, CFD simulation and multizone 0D modeling. The other thermal processes present in the engine block are examined in order to implement suitable submodels. Once the model is complete, it undergoes a validation with experimental transient tests. Afterwards, the ancillary systems for engine thermal management are brought into focus. These systems are considered by means of two new models: a model of heat exchangers and a model of thermo-hydraulic circuits. The development of those models is reported in detail. Lastly, with the referred thermal models integrated in the global simulation tool, a validation study is undertaken. The goal is to validate the ability of the Virtual Engine Model to capture the thermal response of a real engine under various operating conditions. To achieve that, an experimental campaign combining tests under steady-state operation, under transient operation and at different temperatures is conducted in parallel to the corresponding simulation campaign. The capacity of the global engine simulations to replicate the measured thermal evolution is finally demonstrated. / [ES] Los retos actuales en la investigación y desarrollo de trenes de potencia demandan nuevas herramientas computacionales capaces de simular el funcionamento de un vehículo en condiciones muy diversas. Esto se debe, entre otras razones, a que los nuevos estándares de homologación en el sector de la automoción obligan al cumplimiento de las regulaciones de emisiones en cualquier condición posible de conducción en carretera. Los modelos globales de motor o de vehículo proporcionan muchas ventajas a los ingenieros porque permiten reproducir el sistema entero a estudiar, considerando los procesos físicos que tienen lugar en los distintos componentes y las interacciones entre ellos. Esta tesis pretende hacer posible el modelado de los procesos de transmisión de calor en una completa herramienta de simulación de motor desarrollada en el instituto de investigación CMT-Motores Térmicos. Esta herramienta de simulación 0D/1D se denomina Motor Virtual o Virtual Engine Model (VEMOD). El desarrollo de modelos de transmisión de calor comprende el bloque motor y los sistemas auxiliares. El modelo de transmisión de calor en el bloque motor aborda el problema central de la convección en el interior del cilindro mediante una combinación de investigación experimental, simulación CFD y modelado 0D multizona. El resto de procesos térmicos presentes en el bloque motor son examinados para poder implementar submodelos adecuados. Una vez el modelo está terminado, se realiza una validación con ensayos experimentales en régimen transitorio. A continuación, el foco de atención pasa a los sistemas auxiliares de gestión térmica. Estos sistemas se toman en consideración por medio de dos nuevos modelos: un modelo de intercambiadores de calor y un modelo de circuitos termohidráulicos. El desarrollo de los modelos se explica en detalle en esta tesis. Por último, con los citados modelos integrados en el Motor Virtual, se lleva a cabo un estudio de validación. El objectivo es validar la capacidad del Motor Virtual para reproducir la respuesta térmica de un motor real en varias condiciones de funcionamento. Para conseguirlo, se realiza una campaña experimental que combina ensayos en régimen estacionario, en régimen transitorio y a diferentes temperaturas, en paralelo a la campaña de simulación correspondiente. La capacidad de las simulaciones globales de motor para replicar la evolución térmica medida experimentalmente queda finalmente demostrada. / [CA] Els reptes actuals en la recerca i el desenvolupament de trens de potència demanden noves eines computacionals capaces de simular el funcionament d'un vehicle en condicions molt diverses. Açò es deu, entre altres raons, a que els nous estàndards d'homologació al sector de l'automoció obliguen al compliment de les regulacions d'emissions en qualsevol condició possible de conducció en carretera. Els models globals de motor o de vehicle proporcionen molts avantatges als enginyers perquè permeten reproduir el sistema sencer a estudiar, considerant els processos físics que tenen lloc als distints components i les interaccions entre ells. Aquesta tesi pretén fer possible el modelat dels processos de transmissió de calor en una completa eina de simulació de motor desenvolupada a l'institut de recerca CMT-Motores Térmicos. Aquesta eina de simulació 0D/1D s'anomena Motor Virtual o Virtual Engine Model (VEMOD). El desenvolupament de models de transmissió de calor comprén el bloc motor i els sistemes auxiliars. El model de transmissió de calor al bloc motor aborda el problema central de la convecció a l'interior del cilindre mitjançant una combinació de recerca experimental, simulació CFD i modelat 0D multizona. La resta de processos tèrmics presents al bloc motor són examinats per a poder implementar submodels adequats. Una vegada el model està acabat, es fa una validació amb assajos experimentals en règim transitori. A continuació, el focus d'atenció passa als sistemes auxiliars de gestió tèrmica. Aquests sistemes es prenen en consideració per mitjà de dos nous models: un model d'intercanviadors de calor i un model de circuits termohidràulics. El desenvolupament dels models s'explica en detall en aquesta tesi. Per últim, amb els referits models integrats al Motor Virtual, es porta a terme un estudi de validació. L'objectiu és validar la capacitat del Motor Virtual per a reproduir la resposta tèrmica d'un motor real en diverses condicions de funcionament. Per a assolir-ho, es realitza una campanya experimental que combina assajos en règim estacionari, en règim transitori i a diferents temperatures, en paral·lel a la campanya de simulació corresponent. La capacitat de les simulacions globals de motor per a replicar l'evolució tèrmica observada experimentalment queda finalment demostrada. / European funds received in the framework of Horizon 2020’s DiePeR project have contributed to the validation and improvement of the Virtual Engine Model. My own dedication has been funded by Universitat Politècnica de València through the predoctoral contract FPI-S2-2016-1357 of “Programa de Apoyo para la Investigaci´on y Desarrollo (PAID-01-16)”. / Salvador Iborra, J. (2020). A contribution to the global modeling of heat transfer processes in Diesel engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149575 / TESIS

<p>Having an engine model that is accurate but not too complicated is desirable when working with on-board diagnosis or engine control. In this thesis a four state mean value model is introduced. To make the model usable in an on-line automotive application it is discrete and simulated with a fixed step size solver. Modelling is done with simplicity as main object. Some simple static models are also presented. </p><p>To validate the model measuring is carried out in a Scania R124LB truck with a 12 liter six-cylinder turbo charged diesel engine. In general, for this relatively simple model, the mean errors must be considered low. The inlet manifold pressure mean error during highway driving is 3.4\%.</p>

<p>Due to stricter emission legislation, there is a need for more efficient control of diesel engines with exhaust gas recirculation(EGR). In particular, it is important to estimate the air/fuel ratio accurately in transients. Therefore a new engine gas flow model has been developed. This model divides the gas into one part for oxygen and one part for inert gases. Based on this model an observer has been designed to estimate the oxygen concentration in the gas going into the engine, which can be used to calculate the air/fuel ratio. This observer can also be used to estimate the intake manifold pressure. The advantage of estimating the pressure, instead of low pass filtering the noisy signal, is that the observer does not cause time delay.</p>

Having an engine model that is accurate but not too complicated is desirable when working with on-board diagnosis or engine control. In this thesis a four state mean value model is introduced. To make the model usable in an on-line automotive application it is discrete and simulated with a fixed step size solver. Modelling is done with simplicity as main object. Some simple static models are also presented. To validate the model measuring is carried out in a Scania R124LB truck with a 12 liter six-cylinder turbo charged diesel engine. In general, for this relatively simple model, the mean errors must be considered low. The inlet manifold pressure mean error during highway driving is 3.4\%.

Due to stricter emission legislation, there is a need for more efficient control of diesel engines with exhaust gas recirculation(EGR). In particular, it is important to estimate the air/fuel ratio accurately in transients. Therefore a new engine gas flow model has been developed. This model divides the gas into one part for oxygen and one part for inert gases. Based on this model an observer has been designed to estimate the oxygen concentration in the gas going into the engine, which can be used to calculate the air/fuel ratio. This observer can also be used to estimate the intake manifold pressure. The advantage of estimating the pressure, instead of low pass filtering the noisy signal, is that the observer does not cause time delay.

This thesis deals with the description of aircraft engines, their control requirements and control possibilities of these engines. In the practical part, the Jetcat P80-SE engine model was created. This model was then verified against a real engine with measured actual engine speed and temperature. These parameters were then compared with simulated engine speed and temperature. Due to this comparison we can say that it was possible to create a model of the engine that corresponds to the real engine. In addition, the speed controller was designed to meet the control requirements over the speed range. A PI speed controller was designed in different variants, the variants were then compared. Due to the safety limits of the manufacturer were not known, limit values were only implemented to show how the limitation could be implemented.

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