184 research outputs found

    30th International Conference on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2017)

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    Proceedings of COMADEM 201

    Adaptive torque-feedback based engine control

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    The aim of this study was to develop a self-tuning or adaptive SI engine controller using torque feedback as the main control variable, based on direct/indirect measurement and estimation techniques. The indirect methods include in-cylinder pressure measurement, ion current measurement, and crankshaft rotational frequency variation. It is proposed that torque feedback would not only allow the operating set-points to be monitored and achieved under wider conditions (including the extremes of humidity and throttle transients), but to actively select and optimise the set-points on the basis of both performance and fuel economy. A further application could allow the use of multiple fuel types and/or combustion enhancing methods to best effect. An existing experimental facility which comprised a Jaguar AJ-V8 SI engine coupled to a Heenan-Froude Dynamatic GVAL (Mk 1) dynamometer was adopted for this work, in order to provide a flexible distributed engine test system comprising a combined user interface and cylinder pressure monitoring system, a functional dynamometer controller, and a modular engine controller which is close coupled to an embedded PC has been created. The considerable challenges involved in creating this system have meant that the core research objectives of this project have not been met. Nevertheless, an open-architecture software and hardware engine controller and independent throttle controller have been developed, to the point of testing. For the purposes of optimum ignition timing validation and combustion knock detection, an optical cylinder pressure measurement system with crank angle synchronous sampling has been developed. The departure from the project’s initial aims have also highlighted several important aspects of eddy-current dynamometer control, whose closed-loop behaviour was modelled in Simulink to study its control and dynamic response. The design of the dynamometer real-time controller was successfully implemented and evaluated in a more contemporary context using an embedded digital controller.EThOS - Electronic Theses Online ServiceSchool of Mechanical & Systems EngineeringNewcastle UniversityGBUnited Kingdo

    Sustainable development of refrigerator systems using replacement environmentally acceptable refrigerants

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    Environmental considerations have led to the phase out of chlorofluorocarbon (CFC) refrigerants from the domestic refrigeration industry. One intriguing aspect is that the chlorine in CFCs is a good lubricating agent and any deterioration of system performance may adversely influence other environmental considerations. Based on the above, the aim of this research is to address the sustainable development of domestic refrigeration systems using the replacement refrigerant HFC-134a. The work focuses on the emissions that may arise if the electrical consumption of the product deteriorates or its durability is curtailed. Tribological characteristics on compressor components influence both of these product attributes and therefore a thorough system analysis was carried out. An in-house built experimental test rig, which monitored slight variations in the electrical power drawn by a reciprocating hermetic compressor, was used under different experimental conditions. Furthermore, a detailed life cycle assessment on a domestic refrigerator was performed to help quantify the ensuing environmental burdens. In this way, a relation between tribological characteristics, power consumption and environmental impact was studied. Results have shown that the CFC substitute will increase friction and wear characteristics on the aluminium alloy connecting rod and the steel gudgeon pin. These characteristics led to an increase in the electrical energy consumption of the compressor such that the indirect global warming implications are set to rise with HFC-134a. If the sustainable development of this product is to be ascertained then a change in refrigerants alone will not suffice. New design considerations, primarily aimed at servicing and extending the life of the hermetic compressor itself, are considered. This work helps stimulate new ideas to address environmental issues influenced by traditional engineering disciplines. For this reason additional future research work, which will help determine these implications further, is outlined

    Sliding mode control of automotive electronic valve system under weighted try-once-discard protocol

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    In this paper, the sliding mode control problem is addressed for the automotive electronic valve system, which is described by the Markovian model according to the voltage failure. It is supposed that both the system states and the system modes are unavailable to the controller. In order to avoid data collision on the sensor-to-controller transmission, the scheduling among the sensor nodes is ruled by the weighted try-once-discard protocol. A mode detector via a hidden Markovian model is introduced, and an asynchronous token-dependent state observer is proposed. Dependent on the hidden mode information and current token directive, a sliding mode controller is constructed to assure the reachability of a sliding region. Besides, the hidden Markovian model approach is developed to derive mean-square stability conditions for the augmented system. Eventually, simulation studies are provided to demonstrate the validity of the proposed control scheme for the system under consideration

    Quality of Service in Vehicular Ad Hoc Networks: Methodical Evaluation and Enhancements for ITS-G5

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    After many formative years, the ad hoc wireless communication between vehicles has become a vehicular technology available in mass production cars in 2020. Vehicles form spontaneous Vehicular Ad Hoc Networks (VANETs), which enable communication whenever vehicles are nearby without need for supportive infrastructure. In Europe, this communication is standardised comprehensively as Intelligent Transport Systems in the 5.9 GHz band (ITS-G5). This thesis centres around Quality of Service (QoS) in these VANETs based on ITS-G5 technology. Whilst only a few vehicles communicate, radio resources are plenty, and channel congestion is a minor issue. With progressing deployment, congestion control becomes crucial to preserve QoS by preventing high latencies or foiled information dissemination. The developed VANET simulation model, featuring an elaborated ITS-G5 protocol stack, allows investigation of QoS methodically. It also considers the characteristics of ITS-G5 radios such as the signal attenuation in vehicular environments and the capture effect by receivers. Backed by this simulation model, several enhancements for ITS-G5 are proposed to control congestion reliably and thus ensure QoS for its applications. Modifications at the GeoNetworking (GN) protocol prevent massive packet occurrences in a short time and hence congestion. Glow Forwarding is introduced as GN extension to distribute delay-tolerant information. The revised Decentralized Congestion Control (DCC) cross-layer supports low-latency transmission of event-triggered, periodic and relayed packets. DCC triggers periodic services and manages a shared duty cycle budget dedicated to packet forwarding for this purpose. Evaluation in large-scale networks reveals that this enhanced ITS-G5 system can reliably reduce the information age of periodically sent messages. The forwarding budget virtually eliminates the starvation of multi-hop packets and still avoids congestion caused by excessive forwarding. The presented enhancements thus pave the way to scale up VANETs for wide-spread deployment and future applications

    ESSE 2017. Proceedings of the International Conference on Environmental Science and Sustainable Energy

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    Environmental science is an interdisciplinary academic field that integrates physical-, biological-, and information sciences to study and solve environmental problems. ESSE - The International Conference on Environmental Science and Sustainable Energy provides a platform for experts, professionals, and researchers to share updated information and stimulate the communication with each other. In 2017 it was held in Suzhou, China June 23-25, 2017

    Advances on Mechanics, Design Engineering and Manufacturing III

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    This open access book gathers contributions presented at the International Joint Conference on Mechanics, Design Engineering and Advanced Manufacturing (JCM 2020), held as a web conference on June 2–4, 2020. It reports on cutting-edge topics in product design and manufacturing, such as industrial methods for integrated product and process design; innovative design; and computer-aided design. Further topics covered include virtual simulation and reverse engineering; additive manufacturing; product manufacturing; engineering methods in medicine and education; representation techniques; and nautical, aeronautics and aerospace design and modeling. The book is organized into four main parts, reflecting the focus and primary themes of the conference. The contributions presented here not only provide researchers, engineers and experts in a range of industrial engineering subfields with extensive information to support their daily work; they are also intended to stimulate new research directions, advanced applications of the methods discussed and future interdisciplinary collaborations

    Mechatronic Systems

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    Mechatronics, the synergistic blend of mechanics, electronics, and computer science, has evolved over the past twenty five years, leading to a novel stage of engineering design. By integrating the best design practices with the most advanced technologies, mechatronics aims at realizing high-quality products, guaranteeing at the same time a substantial reduction of time and costs of manufacturing. Mechatronic systems are manifold and range from machine components, motion generators, and power producing machines to more complex devices, such as robotic systems and transportation vehicles. With its twenty chapters, which collect contributions from many researchers worldwide, this book provides an excellent survey of recent work in the field of mechatronics with applications in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education. We would like to thank all the authors who have invested a great deal of time to write such interesting chapters, which we are sure will be valuable to the readers. Chapters 1 to 6 deal with applications of mechatronics for the development of robotic systems. Medical and assistive technologies and human-machine interaction systems are the topic of chapters 7 to 13.Chapters 14 and 15 concern mechatronic systems for autonomous vehicles. Chapters 16-19 deal with mechatronics in manufacturing contexts. Chapter 20 concludes the book, describing a method for the installation of mechatronics education in schools
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