Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Bibliography: leaf 72. / by Yuji Hanawa. / M.S.

Driven by the strict fuel consumption and CO2 legislations in Europe and many countries, various technologies have been developed to improve the fuel economy of conventional internal combustion engines. Gasoline engine downsizing has become a popular and effective approach to reduce fleet CO2 emissions of passenger cars. This is typically achieved in the form of boosted direct injection gasoline engines equipped with variable valve timing devices. Downsized gasoline engines reduce vehicle fuel consumption by making engine operate more at higher load to reduce pumping losses and also through reducing total engine friction losses. However, their compression ratio (CR) and efficiency are constrained by knocking combustion as well as the low speed pre-ignition phenomena. Miller cycle is typically achieved in an engine with reduced effective CR through Early Intake Valve Closure (EIVC) or Later Intake Valve Closure (LIVC). This technology has been adopted on modern gasoline engines to reduce in-cylinder charge temperature and enable a higher geometric CR to be used for better fuel economy. The present work investigated the effectiveness and underlying process of a Miller cycle based approach for improving fuel consumption of a boosted downsized gasoline engine. A single cylinder direct injection gasoline engine and the testing facilities were set up and used for extensive engine experiments. Both EIVC and LIVC approaches were tested and compared to the conventional Otto cycle operation with a standard cam profile. Synergy between Miller cycle valve timings and different valve overlap period was analysed. Two pistons with different CRs were used in the Miller cycle engine testing to enable its full potential to be evaluated. The experimental study was carried out in a large engine operation area from idle to up to 4000rpm and 25.6bar NIMEP to determine the optimal Miller cycle strategy for improved engine fuel economy in real applications. In addition, the increased exhaust back pressure and friction losses corresponding to real world boosting devices were calculated to evaluate Miller cycle benefits at high loads in a production engine. The results have shown that EIVC combined with high CR can offer up to 11% reduction of fuel consumption in a downsized gasoline engine with simple setup and control strategy. At the end, this thesis presents an Miller cycle based approach for maximising fuel conversion efficiency of a gasoline engine by combining three-stage cam profiles switching and two-stage variable compression ratio.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Ocean Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by H.T. Chen. / Ph.D.

Orientador: Kléber Pereira Lanças / Banca: Alberto Kazushi Nagaoka / Banca: Flavio Rielli Mazetto / Resumo: O setor sucroalcooleiro brasileiro encontra-se em pleno processo de modernização, utilizando novas tecnologias em diversas áreas o que demanda mão-de-obra qualificada dos técnicos envolvidos. A atual realidade deste setor frente ao avanço da produção de cana-de-açúcar, aos problemas causados pela queima da palha e da crescente demanda por mecanização agrícola nas diversas etapas do processo produtivo, torna a modernização do campo um caminho inevitável. Um dos fatores que vêm sendo analisado e pesquisado de forma mais intensa é o consumo de combustível das colhedoras mecanizadas de cana-de-açúcar, visto que o mesmo está além dos valores estimados para essa operação. O alto consumo é decorrente da falta de treinamento adequado dos operadores, que trabalham com a máquina em potência máxima a maior parte do tempo, mesmo quando não é necessário. Este trabalho teve como objetivo avaliar o consumo de colhedoras de cana-de-açúcar, para isso foram analisadas duas colhedoras: CASE IH modelo A8800, em canaviais de alta produtividade (mais de 100 t.ha-1), e CASE IH modelo A7700, em canaviais de menor produtividade (menos de 40 t.ha-1). As colhedoras foram avaliadas em três faixas de velocidade (5 a 6 km.h-1, 6 a 7 km.h-1 e 7 a 8 km.h-1) e três diferentes rotações do motor (1900 RPM, 2000 RPM e 2100 RPM). Os resultados mostraram que em canaviais de maior produtividade não foi viável utilizar a máquina na rotação de 1900 RPM, abaixo da recomendada pelos fabricantes (2100 RPM). A colhedora A8800 teve consumo horário médio menor, quando utilizada com 2000 RPM no motor (54,4 L.h-1). O mesmo ocorreu para o consumo de combustível por tonelada de cana-de-açúcar colhida, sendo o consumo a 1900 RPM do motor o mais alto (0,60 L.t-1). Nas áreas de menor produtividade o menor... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Brazilian sugar and ethanol sector is in the process of modernization, by using new technologies in several areas which demand skilled labor of the technicians involved. The actual reality of this sector forward to advancing the production of sugar cane, the problems caused by the burning of straw and growing demand for agricultural mechanization in the different of the productive process, modernization of the countryside makes an inevitable path. One of the factors that have been examined and studied more intensively is the fuel consumption of mechanized harvesters for sugar cane, since it is beyond the estimated values for this operation. The high consumption results from the inadequate training of operators, working with the machine at full power most of the time, even when not necessary. This work was aimed at evaluating the consumption of sugarcane's harvesters, to do this two sugarcane's harvesters were analyzed: CASE IH model A8800 in sugarcane high yield (over 100 t.ha-1), and CASE IH model A7700, lower yield (less than 40 t.ha-1). The harvester were evaluated at three speed ranges (5-6 km.h-1, 6-7 km.h-1 and 7-8 km.h-1) and three different engine speed (1900, 2000 and 2100 revolutions per minute). The results showed that higher yield of sugarcane field was not viability of using the machine well below by the manufacturer recommended (1900 RPM). The harvester A8800 the meddle of hourly consumption was lower when used the engine to 2000 RPM (54.4 l.h-1). The same happened to the fuel consumption... (Complete abstract click electronic access below) / Mestre

Thesis. 1975. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. / Bibliography: leaves 135-136. / M.C.P.

La congestion du trafic dans nos villes est un problème qui entrave la qualité de vie. L'intersection est un endroit où les congestions se produisent le plus fréquemment. Par conséquent, au lieu d'étendre les infrastructures, il serait plus intéressant économiquement de s’ocupper de la résolution du problème des retards en développant les stratégies de contrôle de la circulation.Les travaux de cette thèse concerne l’étude des intersections dites « intelligentes » dépourvues de feux de signalisation, et où la coopération est réalisée à partir de la communication véhicule-infrastructure (V2I). L’objectif étant de proposer une modélisation coopérative de ces intersections visant à réduire à la fois les temps de retards et la consommation de carburant.La méthode de résolution du problème comporte deux volets principaux. Le premier volet concerne l'itinéraire devant être choisi par les véhicules pour arriver à leur destination à partir d’un point de départ. Le deuxième volet étant les procédures coopératives proposées afin de permettre aux véhicules de passer rapidement et économiquement à travers chaque intersection. D'une part, selon les informations envoyées en temps réel par les véhicules via la communication V2I à l’intérieur d’une zone de communication, chaque intersection exécute un algorithme soit de « Programmation Dynamique » soit de « Colonie d'Abeilles Artificielles » suivant la taille du trafic et ceci afin de donner aux véhicules l’ordre de passage minimisant le temps de retard dans les intersections. D'autre part, et après avoir reçu l’ordre de passage, chaque véhicule doit calculer son profil optimal de vitesse lui assurant une consommation minimale de carburant.Une série de simulations a ainsi été exécutée sous différents volumes de trafic afin de montrer la robustesse et la performance des méthodes proposées. Les résultats ont aussi été comparés avec d'autres méthodes de contrôle de la littérature et leur efficacité a ainsi été validée. / The traffic congestion is one of the most serious problems limiting the improvement of standing of life. The intersection is a place where the jams occur the most frequently. Therefore, it is more effective and economical to relieve the problem of the heavy traffic delays by ameliorating the traffic control strategies, instead of extending the infrastructures.The proposed method is a cooperative modeling to solve the problem of reducing traffic delays and decreasing fuel consumption simultaneously in a network of intersections without traffic lights, where the cooperation is executed based on the connection of Vehicle-to-Infrastructure (V2I). The resolution contains two main steps. The first step concerns the itinerary. An itinerary presents a list of intersections chosen by vehicles to arrive at their destinations from their origins. The second step is related to the following proposed cooperative procedures to make vehicles to pass through each intersection rapidly and economically: on the one hand, according to the real-time information sent by vehicles in the edge of the communication zone via V2I, each intersection applies Dynamic Programming (DP) or Artificial Bee Colony (ABC) to cooperatively optimize the vehicle passing sequence in intersection with the minimal time delay under the relevant safety constraints; on the other hand, after receiving this sequence, each vehicle finds the optimal speed profiles with the minimal fuel consumption by an exhaustive search.A series of simulation are executed under different traffic volumes to present the performance of proposed method. The results are compared with other control methods and research papers to prove the our new traffic control strategy.

<p>The situation when driving in dense traffic and at low speeds is called Stop and Go. A controller for automatic following of the car in front could under these conditions reduce the driver's workload and keep a safety distance to the preceding vehicle through different choices of gear and engine torque. The aim of this thesis is to develop such a controller, with an additional focus on lowering the fuel consumption. With help of GPS, 3D-maps and sensors information about the slope of the road and the preceding vehicle can be obtained. Using this information the controller is able to predict future possible control actions and an optimization algorithm can then find the best inputs with respect to some criteria. The control method used is Model Predictive Control (MPC) and as the name indicate a model of the control object is required for the prediction. To find the optimal sequence of inputs, the optimization method Dynamic Programming choose the one which lead to the lowest fuel consumption and satisfactory following. Simulations have been made using a reference trajectory which was measured in a real traffic jam. The simulations show that it is possible to follow the preceding vehicle in a good way and at the same time reduce the fuel consumption with approximately 3 %.</p>

<p>This thesis is an approach to improve a two-mode hybrid electric vehicle, which is currently under development by GM, with respect to fuel consumption. The study is not only restricted to the specific two-mode HEV but also presents results regarding parallel as well as serial HEV’s. GM whishes to verify if the online-based controller in the prototype vehicle utilizes the most of the HEV ability and if there is more potential to lower the fuel consumption. The purpose is that the results and conclusions from this work are to be implemented in the controller to further improve the vehicle’s performance. To analyze the behavior of the two-mode HEV and to see where improvements can be made, models of its driveline and components are developed with a focuson losses and efficiency. The models are implemented in MATLAB together with an optimization algorithm based on Dynamic Programming. The models are validated against data retrieved from the prototype vehicle and various cases with different inputs is set up and optimized over the NEDC cycle. Compensation for cold starts and NOx emissions are also implemented in the final model. Deliberate simplifications are made regarding the modeling of the power split’s functionality due to the limited amount of time available for this thesis. The optimizations show that there is potential to lower the fuel consumptionfor the two-mode HEV. The results are further analyzed and the behavior of the engine, motors/generators and battery are compared with recorded data from a prototype vehicle and summarized to a list of suggestions to improve fuel economy.</p>

<p>The department REI/EP at DaimlerChrysler Research and Technology and the Laboratory for Efficient Energy Systems at Trier University of Applied Science, are developing control functions and fuel optimal strategies for low speed conditions. The goal of this thesis project was to further develop the fuel optimal operating strategies, and implement them into a test vehicle equipped with a dSPACE environment. This was accomplished by making optimal reference signals using dynamic programming. Optimal, in this case, means signals that results in low fuel consumption, comfortable driving, and a proper distance to the preceding vehicle. These reference signals for the velocity and distance are used by an MPC controller (Model Predictive Control) to control the car. In every situation a suitable reference path is chosen, depending on the velocities of both vehicles, and the distance. The controller was able to follow another vehicle in a proper way. The distance was kept, the driving was pleasant, and it also seems like it is possible to save fuel. When accepting some deviations in distance to the preceding car, a fuel reduction of 8 % compared to the car in front can be achieved.</p>

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