Hybrid Low-Order Modeling for Conceptual Vehicle Design

Design freedom, and particularly the freedom to incorporate innovative designs and strategies, is greatest at the very beginning of vehicle conceptual design. Conversely, this is when the least knowledge of the product exists. As product content decisions are made the level of freedom in the design decreases and the design becomes locked in. The majority of vehicle lifecycle cost is also set by the end of vehicle conceptual design. This makes it critical to make well-informed and validated decisions in the concept design phase to avoid expensive iterations and redesign in the detailed design phase. Parametric vehicle modeling permits rapid iteration and optimization of vehicles in the conceptual design phase. A significant portion of vehicle design can be optimized parametrically without knowing specific Computer Aided Design (CAD) based details. Many overall vehicle characteristics such as curb mass, center of gravity location, key dimensions, occupant packaging and cargo volume can all be assessed and improved at the parametric level. Key vehicle performance measures can also be determined to a high level of confidence. In developing vehicle dimensions for a parametric model it is recommended to build up a vehicle using an inside-out approach centered on effective, knowledge-based occupant packaging. This work develops a continuum of dimensional parameters which tie vehicle internal and external dimensions together; it employs a combination of industry standard and author-defined component dimensions which make up overall vehicle outside dimensions. An effective continuum of functional parameters is also developed. In order to develop and optimize models for a desired vehicle type and size class, a knowledge base of vehicle typical values for key dimensional parameters has been compiled using a combination of data sources and field measurements. These values provide a useful starting point for the vehicle design optimization process. They also increase optimization effectiveness and ensure that the optimization begins within a valid design space. This work also develops a parametric modeling, scenario builder and optimization software framework which provides a design and optimization tool for vehicle design with trade-off evaluation tools. These parametric design methods improve design maturity prior to beginning vehicle detailed design

Machine Learning Techniques for High Performance Engine Calibration

Ever since the advent of electronic fuel injection, auto manufacturers have been able to increase fuel efficiency and power production, and to meet stricter emission standards. Most of these systems use engine sensors (Speed, Throttle Position, etc.) in concert with look-up tables to determine the correct amount of fuel to inject. While these systems work well, it is time and labor intensive to fine tune the parameters for these look-up tables. In general, automobile manufacturers are able to absorb the cost of this calibration since the variation between engines in a new model line is often small enough as to be inconsequential for a specific calibration. However, a growing number of drivers are interested in modifying their vehicles with the intent of improving performance. While some aftermarket performance upgrades can be accounted for by the original manufacturer equipped (OEM) electronic control unit (ECU), other more significant changes, such as adding a turbocharger or installing larger fuel injectors, require more drastic accommodations. These modifications often require an entirely new ECU calibration or an aftermarket ECU to properly control the upgraded engine. The problem is now that the driver becomes responsible for the calibration of the ECU for this "new" engine. However, most drivers are unable to devote the resources required to achieve a calibration of the same quality as the original manufacturers. At best, this results in reduced fuel economy and performance, and at worst, unsafe and possibly destructive operation of the engine. The purpose of this thesis is to design and develop--using machine learning techniques--an approximate predictive model from current engine data logs, which can be used to rapidly and incrementally improve the calibration of the engine. While there has been research into novel control methods for engine air-fuel ratio control, these methods are inaccessible to the majority of end users, either due to cost or the required expertise with engine calibration. This study shows that there is a great deal of promise in applying machine learning techniques to engine calibration and that the process of engine calibration can be expedited by the application of these techniques

Quantifying Perception-Based Attributes in Design: A Case Study on the Perceived Environmental Friendliness of Vehicle Silhouettes.

Design optimization problems have traditionally used engineering functionality attributes to inform the design of products and systems. However, the quantification and inclusion of subjective attributes has become a necessary part of the product design process. Previous research has assessed the aesthetics, emotional appeal, and expressiveness of "concept-based" product attributes (such as luxury or sportiness) in products. Environmental friendliness is a new product attribute that has emerged in prominence as consumers and manufacturers become more concerned with issuesof sustainability and the "footprint" on the environment. In the automotive industry, there is an increased interest not only in making more fuel efficient vehicles, but also in making them visually appealing in a way that conveys environmental consciousness. Present day trends already show an increase in the number of fuel efficient and alternative powertrain vehicles being introduced in the market; it is expected that in the next few years there will be a large number of different hybrid powertrain vehicles on the market. Depending on market trends and government regulations, fuel economy may not be the only driver for the purchase of fuel efficient vehicles when the price premium paid for the new technology does not result in a timely payback in fuel cost savings. Previous research has shown that people used subjective reasoning, including styling, as a determining factor for purchasing hybrid vehicles. Using methods from psychology and engineering, this dissertation presents a methodology to quantify subjective attributes for inclusion in design optimization models. A demonstration case study addresses the quantification of a perceptual design attribute named perceived environmental friendliness (PEF). A modeling framework that consists of stimuli development using design of experiments, survey design, and statistical analysis of data is presented. The model derived is included in a design optimization framework that considers how variables that influence PEF tradeoff with those that impact fuel economy. Results indicate that under certain conditions, there is a tradeoff between PEF and fuel economy; as PEF increases, the fuel economy decreases.Ph.D.Design ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75934/1/tnreid_1.pd

CAE - PROCESS AND NETWORK : A methodology for continuous product validation process based on network of various digital simulation methods

CAE ProNet methodology is to develop CAE network considering interdependencies among digital validations. Utilizing CAE network and considering industrial requirements, an algorithm is applied to execute a product, vehicle development phase, and load case priority oriented CAE process. Major advantage of this research work is to improve quality of simulation results, reducing time-to-market and decreasing dependencies on hardware prototype

Automotive component product development enhancement through multi-attribute system design optimization in an integrated concurrent engineering framework

Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, 2005.Includes bibliographical references (p. 211-218).Automotive industry is facing a tough period. Production overcapacity and high fixed costs constrain companies' profits and challenge the very same existence of some corporations. Strangulated by the reduced cash availability and petrified by the organizational and products' complexity, companies find themselves more and more inadequate to stay in synch with the pace and the rate of change of consumers' and regulations' demands. To boost profits, nearly everyone pursue cost cutting. However, aggressive cost cutting as the sole approach to fattening margins results invariably in a reduction of operational capabilities which is likely to result in a decline in sales volume that leads to further cost reductions in a continuous death spiral. Long-term profitable growth requires, instead, a continuous flow of innovative products and processes. The focus should be, therefore, shifted from cost reduction to increased throughput. Automotive companies need to change their business model, morphing into new organizational entities based on systems thinking and change, which are agile and can swiftly adapt to the new business environment. The advancement of technology and the relentless increase in computing power will provide the necessary means for this radical transformation. This transformation cannot happen if the Product Development Process (PDP) does not break the iron gate of cycle time-product cost-development expenses-reduced product performance that constrains it. A new approach to PD should be applied to the early phases, where the leverage is higher, and should be targeted to dramatic reduction of the time taken to perform design iterations, which, by taking 50-70% of the total development time, are a burden of today's practice. Multi-disciplinary Design(cont.) Analysis and Optimization, enabled by an Integrated Concurrent Engineering virtual product development framework has the required characteristics and the potential to respond to today's and tomorrow's automotive challenges. In this new framework, the product or system is not defined by a rigid CAD model which is then manipulated by product team engineers, but by a parametric flexible architecture handled by optimization and analysis software, with limited user interaction. In this environment, design engineers govern computer programs, which automatically select appropriately combinations of geometry parameters and drive seamlessly the analyses software programs (structural, fluid dynamic, costing, etc) to compute the system's performance attributes. Optimization algorithms explore the design space, identifying the Pareto optimal set of designs that satisfy the multiple simultaneous objectives they are given and at the same time the problem's constraints. Examples of application of the MDO approach to automotive systems are multiplying. However, the number of disciplines and engineering aspects considered is still limited to few (two or three) thus not exploiting the full potential the approach deriving from multi-disciplinarity. In the present work, a prototype of an Enhanced Development Framework has been set up for a particular automotive subsystem: a maniverter (a combination of exhaust manifold and catalytic converter) for internal combustion engines ...by Massimo Usan.S.M

Actas do 12º Encontro Português de Computação Gráfica

Actas do 12º Encontro Portugês de Computação Gráfica, Porto, 8-10 de Outubro de 2003O Encontro Português de Computação Gráfica teve lugar nesse ano 2003, naquela que foi a sua 12ª edição, no ISEP – Instituto Superior de Engenharia do Porto, entre os 8 a 10 de Outubro. O 12º Encontro Português de Computação Gráfica (12EPCG) veio no seguimento de encontros anteriores realizados anualmente e reuniu investigadores, docentes e profissionais nacionais e estrangeiros, que realizam trabalho ou utilizam a Computação Gráfica, Realidade Virtual e Multimédia, assim como todas as suas áreas afins, no sentido de permitir a divulgação de projectos realizados ou em curso e fomentar a troca de experiências e a discussão de questões relacionadas com a Computação Gráfica em Portugal, entre as comunidades académica,industrial e a de utilizadores finais. Este é o livro de actas do 12EPCG.Fundação Ilídio PinhoFC

Integration of sketch-based ideation and 3D modeling with CAD systems

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis is concerned with the study of how sketch-based systems can be improved to enhance idea generation process in conceptual design stage. It is also concerned with achieving a kind of integration between sketch-based systems and CAD systems to complete the digitization of the design process as sketching phase is still not integrated with other phases due to the different nature of it and the incomplete digitization of sketching phase itself. Previous studies identified three main related issues: sketching process, sketch-based modeling, and the integration between the digitized design phases. Here, the thesis is motivated from the desire to improve sketch-based modeling to support idea generation process but unlike previous studies that only focused on the technical or drawing part of sketching, this thesis attempts to concentrate more on the mental part of the sketching process which play a key role in developing ideas in design. Another motivation of this thesis is to produce a kind of integration between sketch-based systems and CAD systems to enable 3D models produced by sketching to be edited in detailed design stage. As such, there are two main contributions have been addressed in this thesis. The first contribution is the presenting of a new approach in designing sketch-based systems that enable more support for idea generation by separating thinking and developing ideas from the 3D modeling process. This kind of separation allows designers to think freely and concentrate more on their ideas rather than 3D modeling. the second contribution is achieving a kind of integration between gesture-based systems and CAD systems by using an IGES file in exchanging data between systems and a new method to organize data within the file in an order that make it more understood by feature recognition embedded in commercial CAD systems.This study is funded by the Ministry of Higher Education of Egypt

CAE - PROCESS AND NETWORK : A methodology for continuous product validation process based on network of various digital simulation methods

CAE ProNet methodology is to develop CAE network considering interdependencies among digital validations. Utilizing CAE network and considering industrial requirements, an algorithm is applied to execute a product, vehicle development phase, and load case priority oriented CAE process. Major advantage of this research work is to improve quality of simulation results, reducing time-to-market and decreasing dependencies on hardware prototype

Novel methods of drag reduction for squareback road vehicles

Road vehicles are still largely a consumer product and as such the styling of a vehicle becomes a significant factor in how commercially successful a vehicle will become. The influence of styling combined with the numerous other factors to consider in a vehicle development programme means that the optimum aerodynamic package is not possible in real world applications. Aerodynamicists are continually looking for more discrete and innovative ways to reduce the drag of a vehicle. The current thesis adds to this work by investigating the influence of active flow control devices on the aerodynamic drag of square back style road vehicles. A number of different types of flow control are reviewed and the performance of synthetic jets and pulsed jets are investigated on a simple 2D cylinder flow case experimentally. A simplified ¼ scale vehicle model is equipped with active flow control actuators and their effects on the body drag investigated. The influence of the global wake size and the smaller scale in-wake structures on vehicle drag is investigated and discussed. Modification of a large vortex structure in the lower half of the wake is found to be a dominant mechanism by which model base pressure can be influenced. The total gains in power available are calculated and the potential for incorporating active flow control devices in current road vehicles is reviewed. Due to practicality limitations the active flow control devices are currently ruled out for implementation on a road vehicle. The knowledge gained about the vehicle model wake flow topology is later used to create drag reductions using a simple and discrete passive device. The passive modifications act to support claims made about the influence of in wake structures on the global base pressures and vehicle drag. The devices are also tested at full scale where modifications to the vehicle body forces were also observed