233 research outputs found

    Decision makings in key remanufacturing activities to optimise remanufacturing outcomes : a review

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    The importance of remanufacturing has been increasing since stricter regulations on protecting the environment were enforced. Remanufacturing is considered as the main means of retaining value from used products and components in order to drive a circular economy. However, it is more complex than traditional manufacturing due to the uncertainties associated with the quality, quantities and return timing of used products and components. Over the past few years, various methods of optimising remanufacturing outcomes have been developed to make decisions such as identifying the best End-Of-Life (EOL) options, acquiring the right amounts of cores, deciding the most suitable disassembly level, applying suitable cleaning techniques, and considering product commonality across different product families. A decision being made at one remanufacturing activity will greatly affect the decisions at subsequent activities, which will affect remanufacturing outcomes, i.e. productivity, economic performance effectiveness, and the proportion of core that can be salvaged. Therefore, a holistic way of integrating different decisions over multiple remanufacturing activities is needed to improve remanufacturing outcomes, which is a major knowledge gap. This paper reviews current remanufacturing practice in order to highlight both the challenges and opportunities, and more importantly, offers useful insights on how such a knowledge gap can be bridged

    A novel genetic programming approach to the design of engine control systems for the voltage stabilisation of hybrid electric vehicle generator outputs

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    This paper describes a Genetic Programming based automatic design methodology applied to the maintenance of a stable generated electrical output from a series-hybrid vehi- cle generator set. The generator set comprises a 3-phase AC generator whose output is subsequently rectified to DC.The engine/generator combination receives its control input via an electronically actuated throttle, whose control integration is made more complex due to the significant system time delay. This time delay problem is usually addressed by model predictive design methods, which add computational complexity and rely as a necessity on accurate system and delay models. In order to eliminate this reliance, and achieve stable operation with disturbance rejection, a controller is designed via a Genetic Programming framework implemented directly in Matlab, and particularly, Simulink. the principal objective is to obtain a relatively simple controller for the time-delay system which doesn’t rely on computationally expensive structures, yet retains inherent disturabance rejection properties. A methodology is presented to automatically design control systems directly upon the block libraries available in Simulink to automatically evolve robust control structures

    A DESIGN METHODOLOGY FOR REMANUFACTURING AND REMANUFACTURABILITY ASSESSMENT

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    Ph.DDOCTOR OF PHILOSOPH

    Development of System Analysis Methodologies and Tools for Modeling and Optimizing Vehicle System Efficiency.

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    Optimizing the vehicle system is essential for achieving higher fuel efficiency. This dissertation addresses the need to better understand energy demand from a vehicle subsystem standpoint and tackles the challenge of optimal hardware and control system design. An energy analysis methodology and Matlab®/Simulink® based tool are developed to account for where the fuel energy supplied to a vehicle system is demanded. A hybrid semi-empirical and analytical approach that combines first principles with detailed component speed and load data is proposed. The methodology and tool are applied to account for the instantaneous and accumulated vehicle subsystem energy usage over a given drive cycle. A comparison of the prevailing fuel economy factors for city and highway driving are presented. Incremental vehicle subsystem changes that account for a fraction of the total energy demand are analyzed to determine individual effects on overall fuel economy. A reverse dynamic optimization methodology is proposed for optimal powertrain integration and control design. A reverse tractive road load demand model developed in Matlab®/Simulink® propagates the required wheel torque and speed derived from vehicle speed and road grade through the powertrain system to determine the required fuel flow for all possible states within the hardware constraints. The control strategy is treated as a multi-stage, multi-dimension decision process, where dynamic programming is applied to find an optimal control policy that minimizes the accumulated fuel flow over a drive cycle. The reverse dynamic optimization methodology and tool are used to assess and develop transmission gear shift, torque converter lock-up clutch, and pedal control strategies that are catered to specific vehicle applications. The reverse model and dynamic optimization technique are extended to virtually optimize variable displacement engine operation taking gear and clutch control interaction effects into account. The reverse model is used for establishing design criteria, such as minimum engine part throttle torque requirements, by determining the required speeds and loads to traverse drive cycles. The advantages of the reverse dynamic optimization approach are demonstrated by performing powertrain matching analyses (i.e., vehicle attribute sensitivity analysis; optimal engine, transmission and axle selection; and variable displacement effects) and key system integration concepts are revealed.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/57640/2/mpapke_1.pd

    Automotive Stirling engine development program

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    The major accomplishments were the completion of the Basic Stirling Engine (BSE) and the Stirling Engine System (SES) designs on schedule, the approval and acceptance of those designs by NASA, and the initiation of manufacture of BSE components. The performance predictions indicate the Mod II engine design will meet or exceed the original program goals of 30% improvement in fuel economy over a conventional Internal Combustion (IC) powered vehicle, while providing acceptable emissions. This was accomplished while simultaneously reducing Mod II engine weight to a level comparable with IC engine power density, and packaging the Mod II in a 1985 Celebrity with no external sheet metal changes. The projected mileage of the Mod II Celebrity for the combined urban and highway CVS cycle is 40.9 mpg which is a 32% improvement over the IC Celebrity. If additional potential improvements are verified and incorporated in the Mod II, the mileage could increase to 42.7 mpg

    Trends in vehicle motion control for automated driving on public roads

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    In this paper, we describe how vehicle systems and the vehicle motion control are affected by automated driving on public roads. We describe the redundancy needed for a road vehicle to meet certain safety goals. The concept of system safety as well as system solutions to fault tolerant actuation of steering and braking and the associated fault tolerant power supply is described. Notably restriction of the operational domain in case of reduced capability of the driving automation system is discussed. Further we consider path tracking, state estimation of vehicle motion control required for automated driving as well as an example of a minimum risk manoeuver and redundant steering by means of differential braking. The steering by differential braking could offer heterogeneous or dissimilar redundancy that complements the redundancy of described fault tolerant steering systems for driving automation equipped vehicles. Finally, the important topic of verification of driving automation systems is addressed

    New advances in vehicular technology and automotive engineering

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    An automobile was seen as a simple accessory of luxury in the early years of the past century. Therefore, it was an expensive asset which none of the common citizen could afford. It was necessary to pass a long period and waiting for Henry Ford to establish the first plants with the series fabrication. This new industrial paradigm makes easy to the common American to acquire an automobile, either for running away or for working purposes. Since that date, the automotive research grown exponentially to the levels observed in the actuality. Now, the automobiles are indispensable goods; saying with other words, the automobile is a first necessity article in a wide number of aspects of living: for workers to allow them to move from their homes into their workplaces, for transportation of students, for allowing the domestic women in their home tasks, for ambulances to carry people with decease to the hospitals, for transportation of materials, and so on, the list don’t ends. The new goal pursued by the automotive industry is to provide electric vehicles at low cost and with high reliability. This commitment is justified by the oil’s peak extraction on 50s of this century and also by the necessity to reduce the emissions of CO2 to the atmosphere, as well as to reduce the needs of this even more valuable natural resource. In order to achieve this task and to improve the regular cars based on oil, the automotive industry is even more concerned on doing applied research on technology and on fundamental research of new materials. The most important idea to retain from the previous introduction is to clarify the minds of the potential readers for the direct and indirect penetration of the vehicles and the vehicular industry in the today’s life. In this sequence of ideas, this book tries not only to fill a gap by presenting fresh subjects related to the vehicular technology and to the automotive engineering but to provide guidelines for future research. This book account with valuable contributions from worldwide experts of automotive’s field. The amount and type of contributions were judiciously selected to cover a broad range of research. The reader can found the most recent and cutting-edge sources of information divided in four major groups: electronics (power, communications, optics, batteries, alternators and sensors), mechanics (suspension control, torque converters, deformation analysis, structural monitoring), materials (nanotechnology, nanocomposites, lubrificants, biodegradable, composites, structural monitoring) and manufacturing (supply chains). We are sure that you will enjoy this book and will profit with the technical and scientific contents. To finish, we are thankful to all of those who contributed to this book and who made it possible.info:eu-repo/semantics/publishedVersio

    Evaluation of a mild-hybrid electric combat vehicle with energy management

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    The desire to reduce fuel consumption and gas emissions, along with increasing demands on electrical energy is driving the evolution of vehicle power system architectures well beyond the conventional single alternator and battery. Amongst the different power system architectures available, are mild-hybrid electric architectures. Such architectures may offer flexibility in balancing the trade-offs associated with minimising fuel consumption, and greater capacity to meet electric energy demands. They allow for a wide range of energy management strategies to be investigated. Such strategies are able to accommodate for the need to reduce fuel consumption, undesirable gas emissions, and the need to meet the increased dependence on electrical energy. The strategies can be implemented by vehicle power management systems running energy management algorithms. Such systems are becoming more common in commercial vehicles, however, they are not commonly found in current military vehicles. This thesis focusses on evaluating the impacts caused to vehicle acceleration, fuel consumption, the time to fully charge/discharge the vehicle battery pack, and the electrical conversion efficiency, when introducing energy management strategies into a baseline mild-hybrid electric combat vehicle under different military stationary and moving scenarios. The scenarios were selected because current vehicle manufacturers and academia have primarily focussed on investigating energy management strategies in urban environments. In comparison, a study involving military scenarios allows a new application domain to be investigated. The thesis describes the mild-hybrid electric combat vehicle baseline, and presents the results of comparing the baseline against one that has been extended to include additional energy management strategies under different military scenarios.Thesis (MPhil) -- University of Adelaide, School of Electrical and Electronic Engineering, 201

    Integrated optimal design for hybrid electric vehicles

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