Dynamic and Fatigue Assessment of Heavy-Duty Engine Valves


Book Description

This book provides findings on the simulation of the valve dynamic to the current technological standards. Above all, it delivers a simulation based and predictive approach on the fatigue strength assessment of four-stroke heavy-duty engine valves. The demand for more efficient combustion engines with fuel flexibility goes along with increasing component requirements regarding strength and durability, while the development costs should remain low. In this context, the present book focuses on the gas exchange valves of heavy-duty engines. Especially, the valves on the exhaust side have an increased risk of fatigue failure. The aim of this book is the generation of a predictive fatigue strength assessment to strengthen the frontloading of the exhaust valve design process and to increase the reliability of the component. In the context of fatigue assessment, this book examines the loads of the exhaust valve during its working cycle. Beside the high temperature and cylinder pressure, further loads act on the exhaust valve like actuation force or an eccentric impact of the valve on the valve seat ring. Furthermore, a bold valve secondary dynamic in the form of valve bending vibrations is observed on the exhaust valves of heavy-duty engines increasing the valve load even more. The cause of this secondary dynamic is unknown. This book investigates the valve loads to get the necessary input for the fatigue strength assessment. With respect to a predictive approach, the determination of valve dynamic and valve loads is based on a multibody simulation model of the valve train. In order to deliver predictive results and a transferable method, this simulation model includes all relevant physical effects to describe the valve dynamic accurately during all valve load phases of the working cycle. With the simulation model, the root cause for the bold valve secondary dynamic is examined iteratively. The model delivers not only the cause for the valve secondary dynamic but most importantly the critical valve loads. These loads deliver the input for the fatigue strength assessment. To ensure the robustness of the load data determined by the simulation model, the sensitivity of influences on the valve load is examined. In this context geometrical misalignment, fluctuations in load data and variable engine operation points are considered. A load collective based on the variation of influences on the valve load is the result of this analysis. All the results of the influence and sensitivity study are generated with the newly developed simulation model of the valve train. Moreover, this book outlines measurements on a testbed engine. In scope of these measurements are temperature and strain measurements of the valve. The generated data validate the simulation model of the valve train. Additionally, the statistical evaluation of the data is used in the subsequent fatigue strength assessment to increase the reliability of the results.




Introduction to Modeling and Control of Internal Combustion Engine Systems


Book Description

Internal combustion engines still have a potential for substantial improvements, particularly with regard to fuel efficiency and environmental compatibility. These goals can be achieved with help of control systems. Modeling and Control of Internal Combustion Engines (ICE) addresses these issues by offering an introduction to cost-effective model-based control system design for ICE. The primary emphasis is put on the ICE and its auxiliary devices. Mathematical models for these processes are developed in the text and selected feedforward and feedback control problems are discussed. The appendix contains a summary of the most important controller analysis and design methods, and a case study that analyzes a simplified idle-speed control problem. The book is written for students interested in the design of classical and novel ICE control systems.




Mathematical Optimization for Efficient and Robust Energy Networks


Book Description

This book presents a collection of energy production and distribution problems identified by the members of the COST Action TD1207 "Mathematical Optimization in the Decision Support Systems for Efficient and Robust Energy Networks". The aim of the COST Action was to coordinate the efforts of the experts in different fields, from academia and industry, in developing innovative tools for quantitative decision making, and apply them to the efficient and robust design and management of energy networks. The work covers three main goals:• to be a nimble while comprehensive resource of several real life business problems with a categorized set of pointers to many relevant prescriptive problems for energy systems;• to offer a balanced mix of scientific and industrial views;• to evolve over time in a flexible and dynamic way giving, from time to time, a more scientific or industrial - or even political in a broad sense - weighed perspective.It is addressed to researchers and professionals working in the field.







Scientific and Technical Aerospace Reports


Book Description

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.




Systems Engineering for Automotive Powertrain Development


Book Description

For the last century, the automotive industry has been dominated by internal combustion engines. Their flexibility of application, driving range, performance and sporty characteristics has resulted in several generations of this technology and has formed generations of engineers. But that is not the end of the story. Stricter legislation and increased environmental awareness have resulted in the development of new powertrain technologies in addition and parallel to the highly optimized internal combustion engine. Hybrid powertrains systems, pure battery electric systems and fuel cell systems, in conjunction with a diverse range of applications, have increased the spectrum of powertrain technologies. Furthermore, automated driving together with intelligent and highly connected systems are changing the way to get from A to B. Not only is the interaction of all these new technologies challenging, but also several different disciplines have to collaborate intensively in order for new powertrain systems to be successfully developed. These new technologies and the resulting challenges lead to an increase in system complexity. Approaches such as systems engineering are necessary to manage this complexity. To show how systems engineering manages the increasing complexity of modern powertrain systems, by providing processes, methods, organizational aspects and tools, this book has been structured into five parts. Starting with Challenges for Powertrain Development, which describes automotive-related challenges at different levels of the system hierarchy and from different point of views. The book then continues with the core part, Systems Engineering, in which all the basics of systems engineering, model-based systems engineering, and their related processes, methods, tools, and organizational matters are described. A special focus is placed on important standards and the human factor. The third part, Automotive Powertrain Systems Engineering Approach, puts the fundamentals of systems engineering into practice by adding the automotive context. This part focuses on system development and also considers the interactions to hardware and software development. Several approaches and methods are presented based on systems engineering philosophy. Part four, Powertrain Development Case Studies, adds the practical point of view by providing a range of case studies on powertrain system level and on powertrain element level and discusses the development of hybrid powertrain, internal combustion engines, e-drives, transmissions, batteries and fuel cell systems. Two case studies on a vehicle level are also presented. The final part, Outlook, considers the development of systems engineering itself with particular focus on information communication technologies. Even though this book covers systems engineering from an automotive perspective, many of the challenges, fundamental principles, conclusions and outlooks can be applied to other domains too. Therefore, this book is not only relevant for automotive engineers and students, but also for specialists in scientific and industrial positions in other domains and anyone who has to cope with the challenge of successfully developing complex systems with a large number of collaborating disciplines.







Combustion Engines Development


Book Description

Combustion Engines Development nowadays is based on simulation, not only of the transient reaction of vehicles or of the complete driveshaft, but also of the highly unsteady processes in the carburation process and the combustion chamber of an engine. Different physical and chemical approaches are described to show the potentials and limits of the models used for simulation.




Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles


Book Description

The light-duty vehicle fleet is expected to undergo substantial technological changes over the next several decades. New powertrain designs, alternative fuels, advanced materials and significant changes to the vehicle body are being driven by increasingly stringent fuel economy and greenhouse gas emission standards. By the end of the next decade, cars and light-duty trucks will be more fuel efficient, weigh less, emit less air pollutants, have more safety features, and will be more expensive to purchase relative to current vehicles. Though the gasoline-powered spark ignition engine will continue to be the dominant powertrain configuration even through 2030, such vehicles will be equipped with advanced technologies, materials, electronics and controls, and aerodynamics. And by 2030, the deployment of alternative methods to propel and fuel vehicles and alternative modes of transportation, including autonomous vehicles, will be well underway. What are these new technologies - how will they work, and will some technologies be more effective than others? Written to inform The United States Department of Transportation's National Highway Traffic Safety Administration (NHTSA) and Environmental Protection Agency (EPA) Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) emission standards, this new report from the National Research Council is a technical evaluation of costs, benefits, and implementation issues of fuel reduction technologies for next-generation light-duty vehicles. Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles estimates the cost, potential efficiency improvements, and barriers to commercial deployment of technologies that might be employed from 2020 to 2030. This report describes these promising technologies and makes recommendations for their inclusion on the list of technologies applicable for the 2017-2025 CAFE standards.