Yes / An examination of the heat partition ratio between the friction surfaces of a disc braking system is presented using finite element analysis (FEA). This includes a 2D static analysis of two semi-infinite bodies in contact with and without an interface layer which represents the interface tribo-layer (ITL). An analytical approach with a finite difference solution was used for cross-comparison with the static FE models. Results from the static model have provided the boundary conditions for a 2D dynamic model, where one rectangular block slides on another (fixed) rectangular block. The effects of normal loads and real contact area have also been studied. / Institution of Mechanical Engineers

Research of movement parameters of motorcars in braking.

Der optimierte Einsatz von ETCS-Bremskurven: - Bestimmung der D-Weg-Länge - neue Auslegung des Sicherheitsabstandes Bahnübergang sD - Fahrzeitbestimmung von ETCS-geführten Zügen - Durchrutschwege und Haltepunkte individuell gestalten - Anpassung der Bremskurven - Geschwindigkeitswechsel in ETCS - Betrachtung der vorhandenen Infrastruktur und des optimierten Einsatzes von ETCS FS:Vorwort 5 Abstract 6 Thesen zur wissenschaftlichen Arbeit 7 Danksagung 8 1 Motivation 9 1.1 Aktueller Stand 9 1.2 Zielstellung 9 1.3 Vorgehensweise 10 2 Theoretische Grundlagen 11 2.1 Was ist eine Infrastruktur? 11 2.2 Was ist eine EdB? 11 2.3 Was ist ETCS? 11 2.4 Transeuropäisches Netz 12 3 Rechtliche Grundlagen 13 3.1 Europäische Gesetzgebung 14 3.2 Nationale Gesetzgebung 14 4 Technische Grundlagen 15 4.1 Ganz-, Teilblock und wandernder Raumabstand 15 4.2 Arten von Zugbremsungen 15 4.3 Repräsentative Züge: Bremsvermögen 16 4.3.1 Reisezüge 16 4.3.2 Güterzüge 17 4.3.3 Expertenschätzung 17 4.4 Nationales Zugbeeinflussungssystem 17 4.4.1 Punktförmige Zugbeeinflussung 17 4.4.2 Linienförmige Zugbeeinflussung 22 4.5 Europäisches Zugbeeinflussungssystem ETCS 25 4.5.1 Spezifikationen 25 4.5.2 Allgemein 25 4.5.3 Die Eurobalise 27 4.5.4 Übertragungsdaten 29 4.5.5 Betriebsarten 30 4.5.6 Aufbau der Fahrzeugeinrichtung 31 4.5.7 Ausrüstungsstufen (Level) 31 4.5.8 Level 3 37 4.5.9 Bremskurven 38 4.5.10 Vertrauensintervall 42 4.5.11 Bremsmodelle 43 5 Fahrzeiten 49 5.1 Ansatz zur Ermittlung der Fahrzeit von PZB 90-geführten Fahrzeugen 49 5.2 Ansatz zur Ermittlung der Fahrzeit von ETCS-geführten Fahrzeugen 50 5.3 Einfluss der Odometrie auf die Bremskurven 50 5.4 Einfluss der Sperrzeit auf die Leistungsfähigkeit einer Strecke 51 5.5 Schwierigkeit bei der Fahrzeitermittlung von ETCS-Fahrzeugen 52 5.6 Vierteiliges Bremsablaufmodell 56 5.7 Fahrzeitenvergleich zwischen ETCS FS und PZB 59 5.7.1 Fahrzeit bis zum Stillstand 59 5.7.2 Geschwindigkeitswechsel 60 5.7.3 Einfahrt im Bf mit Abzweig 61 5.8 Zusammenfassung 64 6 Durchrutschwege und Haltepunkte individuell gestalten 65 6.1 Regeldurchrutschwege nach Ril 819.0202 65 6.2 Optimierte Durchrutschwege 65 6.2.1 Ansatz 1: Ermittlung des Optimums zwischen EoA und SvL mittels Vs 66 6.2.2 Ansatz 2: Optimum zwischen EoA und SvL ermitteln mittels Steigung der Fahrzeitenkurve 70 6.2.3 Formel zur Bestimmung der kürzesten Anhaltezeit 73 6.2.4 Durchrutschweg-Tabellen für die kürzeste Anhaltezeit 75 6.2.5 Optimierter Durchrutschweg für Release Speed 75 6.2.6 Kürzeste Anhaltezeit für Release Speed 78 6.2.7 D-Weg in Abhängigkeit der Zuglänge/variable Gleisnutzlänge 78 6.2.8 Optimierung der Fahrzeit durch Verschiebung vom Ne 5 80 6.3 Entfall von D-Wegen und Fahrzeitverluste 83 6.4 Entfall von D-Wegen mit vorzeitigem Halt 86 6.5 Halteplatz mit unmittelbar folgenden Gefahrpunkten 89 6.6 Zusammenfassung 90 7 Anpassung der Bremskurven 92 7.1 Änderung mittels „Fixed values“ 92 7.1.1 Dynamische Änderung Tdriver und Twarning 92 7.1.2 Änderung Tdriver und Twarning mittels Set 96 7.2 Änderung der Release Speed 97 7.2.1 Fallende Release-Speed 97 7.2.2 Ergänzung einer Umschalt-Release-Speed 98 7.3 Reduzierung der Bremskurvenschar 99 7.3.1 Bestimmung Warning_EBI-Kurve 100 7.3.2 Bestimmung Bremsablaufkurve 101 7.3.3 Bestimmung Indication-Kurve 101 7.3.4 Vergleich mit den bisherigen Bremsablaufkurven 102 7.4 Vergleich der Änderungen 104 7.5 Zusammenfassung 105 8 Geschwindigkeitswechsel 106 8.1 Sicherung von Langsamfahrstellen bei L1 LS 106 8.2 Bestimmung der Bremskurven beim Geschwindigkeitswechsel 106 8.3 Bestimmung von Dbec 108 8.4 Verschiebung von dp_MRSP in Fahrtrichtung 109 8.4.1 Ansatz zur Bestimmung von dp_MRSP 110 8.4.2 Risikoanalyse zur Verschiebung von dp_MRSP in Fahrtrichtung 113 8.5 Änderung von dV_ebi_min und dV_ebi_max 114 8.6 Änderung der Bremskurven 115 8.7 Zusammenfassung 118 9 Betrachtung der vorhandenen Infrastruktur und des optimierten Einsatzes von ETCS FS 120 9.1 Vergleich der D-Wege zwischen PZB und ETCS 120 9.2 Erhöhung der VzG 122 9.3 Erhöhung der Geschwindigkeit in Weichen 122 10 BÜSA: Sicherheitsabstand sd 124 10.1 Ausgangssituation 124 10.2 Ziel 124 10.3 Herangehensweise 125 10.4 Risikoanalyse zum Thema: „Einheitlicher Sicherheitsabstand sd für BÜSA“ 125 10.4.1 Einführung 125 10.4.2 Systemdefinition 125 10.4.3 Analyse des Ist-Zustandes 129 10.4.4 Neuer Ansatz 130 10.4.5 Risikoanalyse 130 10.5 Zusammenfassung 143 11 Zusammenfassung und Ausblick 144 11.1 Zusammenfassung der zwei Lösungsmethoden und die Integration in die vorhandene Infrastruktur 144 11.2 Weiterer Forschungsbedarf 144 Abkürzungsverzeichnis 146 Liste der verwendeten Variablen 149 Abbildungsverzeichnis 150 Tabellenverzeichnis 155 Literaturverzeichnis 157 Anhang A: Parameter 162 Anhang B: Gesprächsprotokolle 164 Anhang C: D-Weg-Tabelle 165

This paper discusses the current and future drivetrain perspectives of powerful mobile machines, especially in regards to TCO and drive performance. For the TCO-impact, the power losses of the components plays a big role and, if they are designed for efficiency, they have a significant and measurable influence. From the braking function point of view, this paper demonstrates not only the advantages of a valve-based over a control algorithm based solution, but also its innovative development directions towards a more sophisticated engine speed controller with optimized heat conversion into the oil. Also for the drivetrain subsystems, innovative components are discussed, like the hybrid control, combining the benefits of a non-feedback and a displacement control in one single assembly, or the variable charge system for further reduced energy consumption of the overall drivetrain.

The thesis presents an intermediate modelling approach to study transient behaviour of vehicle systems, with emphasis put on simplified yet accurate representation of important system elements. A representative non-linear vehicle model is developed in MA TLAB/Simulink environment, where non-linear characteristics of tyre, suspension and braking system are included to capture the dynamic behaviour of a vehicle under transient conditions. The novel aspect of this work is the application of a representative full vehicle-tyre-ABS integrated set-up to study the complicated interaction between tyre and anti-lock braking, under a range of demanding operating conditions, including combined cornering and braking. The modelling methodology involves development of low end vehicle models, based on the Newton-Euler formulation. Subsequently, an intermediate vehicle model is devised, where more details are incorporated such as additional DOF to capture the sprung mass motion in space, along with its non-linear interactions with the un-sprung masses, large angle effects, kinematics of steering/wheels and an appropriate tyre model suitable for transient manoeuvres. Particular attention is paid to the suspension system modelling, through inclusion of non-linear effects in springs, dampers, bump-stops, and anti-roll bars, along with the jacking and anti-dive effects using the virtual work method. The model also incorporates a hydraulic brake model, based on the reduced order brake system dynamics for realistic simulation of the braking manoeuvres. A complex multi-body ADAMS/Chassis model, with much greater level of detail, has also been established to extensively compare and enhance the realistic behaviour of the intermediate vehicle model. During the simulation exercise, the intermediate vehicle model has shown good agreement with the complex ADAMS model, thus justifying the accurate representation of vehicle.non-linear characteristics, particularly the suspension system. The realistic behaviour of the vehicle model is further ascertained with a reliable GPS enabled test vehicle, by performing number of manoeuvres on test tracks, including combined cornering and braking. A representative 4-channel conventional ABS system is modelled and integrated in the intermediate vehicle model. The ABS adopts generic peak seeking approach, employing wheel deceleration and brake slip as control variables. External braking inputs, in form of stepped pressure pulses, are also separately used to represent the transient braking system dynamics. In the current work, different transient tyre models based on the single point contact approach and using Magic Formula steady-state characteristics are applied, while studying the influence of their dynamic behaviour on the ABS system. By employing a representative ABS system in a multi-body vehicle model and considering the particularly demanding situation of combined braking I cornering, it is shown that the models which are adequate for pure braking might struggle when the complicated full vehicle dynamics are excited. It is shown that the first order relaxation length approach may not be sufficient to fully satisfy the requirements of an ABS braking, especially if the relaxation length is not modelled as a variable dependent on tyre slip. In comparison, the modelling approach, where the carcass compliances and contact patch properties are explicitly represented, can handle the oscillatory tyre behaviour associated with ABS braking, in a far more accurate manner. In comparison to the earlier studies, which were mostly conducted for straight-line braking, this thesis stresses the fact that the tyre behaviour can be influenced by the complex interaction of handling and braking, and hence the effect should be captured while investigating or evaluating the performance of a tyre model in relation with ABS simulation.

M.Ing. (Electrical and Electronic Engineering) / Adaptive Cruise Control (ACC) is proposed to assist drivers tedious manual acceleration or braking of the vehicle, as well as with maintaining a safe headway time gap. This thesis proposes, simulates, and implements a vision-based ACC system which uses a single camera to obtain the clearance distance between the preceding vehicle and the ACC vehicle. A three-step vehicle detection framework is used to obtain the position of the lead vehicle in the image. The vehicle coordinates are used in conjunction with the lane width at that point to estimate the longitudinal clearance range. A Kalman filter filters this range signal and tracks the vehicle’s longitudinal position. Since image processing algorithms are computationally intensive, this document addresses how adaptive image cropping improves the update frequency of the vision-based range sensor. A basic model of a vehicle is then derived for which a Proportional-Integral (PI) controller with gain scheduling is used for ACC. A simulation of the system determines whether the ACC algorithm will work on an actual vehicle.

This thesis presents an investigation of braking system characteristics, brake system performance and brake system component design parameters that influence brake pedal force / displacement characteristics as ‘felt’ by the driver in a passenger car. It includes detailed studies of individual brake system component design parameters, operation, and the linear and nonlinear characteristics of internal components through experimental study and simulation modelling. The prediction of brake pedal ‘feel’ in brake system simulation has been achieved using the simulation modelling package AMESim. Each individual brake system component was modelled individually before combining them into the whole brake system in order to identify the parameters and the internal components characteristics that influence the brake pedal ‘feel’. The simulation predictions were validated by experimentally measured data and demonstrated the accuracy of simulation modelling. Axisymmetric Finite Element Analysis (using the ABAQUS software) was used to predict the behaviour of nonlinear elastomeric internal components such as the piston seal and the booster reaction disc which was then included in the AMESim simulation model. The seal model FEA highlighted the effects of master cylinder and caliper seal deformation on the brake pedal ‘feel’. The characteristics of the brake booster reaction disc were predicted by the FEA and AMESim simulation modelling and these results highlighted the importance of the nonlinear material characteristics, and their potential contribution to brake pedal ‘feel’ improvement. A full brake system simulation model was designed, prepared, and used to predict brake system performance and to design a system with better brake pedal ‘feel’. Each of the brake system component design parameters was validated to ensure that the braking system performance was accurately predicted. The critical parameter of brake booster air valve spring stiffness was identified to improve the brake ‘pedal ‘feel’. This research has contributed to the advancement of automotive engineering by providing a method for brake system engineers to design a braking system with improved pedal ‘feel’. The simulation model can be used in the future to provide an accurate prediction of brake system performance at the design stage thereby saving time and cost.

Os sistemas de ar condicionado automotivos sempre se utilizaram do conceito de operação do ciclo termodinâmico por compressão de vapor, sendo necessário para isso componentes básicos tais como fluído refrigerante, trocadores de calor e compressor. Apesar de diversas décadas de pesquisa e desenvolvimento desse sistema, algumas dificuldades ainda permanecem nos dias de hoje. Dessa forma, a investigação de outros mecanismos de refrigeração, que possam ser aplicados em sistemas automotivos de ar condicionado, é bem vinda. Uma dessas possibilidades é a aplicação dos tubos de vórtices, utilizados atualmente para fins industriais. Os tubos de vórtices são dispositivos que operam através da introdução de um fluxo de ar comprimido, sendo que ele possibilita a divisão deste fluxo em duas parcelas: um fluxo de alta temperatura e um fluxo de baixa temperatura. Tal dispositivo apresenta vantagens tais como a não necessidade da utilização de trocadores de calor e de fluídos refrigerantes. Desta forma, ele possibilita uma maior flexibilidade de posicionamento de saídas de ar em pontos do habitáculo do veículo os quais não são permitidos atualmente. A alimentação do tubo de vórtices se dá exclusivamente com fluxo de ar comprimido, que pode ser armazenado para consumo conforme necessidade. Adicionalmente, devido a esta característica, surge a possibilidade de executar o reaproveitamento de energia cinética, que no processo de frenagem é dissipada ao ambiente. O reaproveitamento energético pode ser efetuado através do redirecionamento dessa energia cinética para o compressor de ar. Baseado nessa possibilidade, foram inicialmente obtidos os dados de operação de um sistema de ar condicionado convencional, além do potencial de regeneração energética, sendo estes dados obtidos através de publicações técnicas e cálculos teóricos. Estabeleceu-se uma proposta de configuração dos componentes, assim como modos de operação do sistema. Posteriormente seguiu-se com uma pré-seleção dos componentes que influem diretamente na viabilidade do sistema. Os resultados mostraram a dificuldade de implementação dessa filosofia de sistema para veículos leves (automóveis de passeio), mostrando maior viabilidade para veículos comerciais de grande porte (tais como caminhões), principalmente aqueles dotados de sistema pneumático para a operação dos freios a ar e suspensão pneumática. / Automotive air conditioning systems have always utilized the thermodynamic vapor-compression cycle concept, with the necessity of some basic components as refrigerant fluid, heat exchangers and compressor. Although research and development of these systems have been made along many decades, some difficulties still remain nowadays. Then, the investigation of other mechanisms of refrigeration that could be applied to automotive air conditioning systems are welcome. One of these possibilities is the application of the Vortex Tubes, utilized nowadays for industrial applications. Vortex Tubes are devices that work with the introduction of an air compressed flow. These devices enable the division of the inlet flow in two flow fractions: one high and one low temperature flow. The application of these devices brings advantages, as an example no necessity of heat exchangers and refrigerant fluids. Then it enables a higher flexibility in the positioning of air outlets in some cabin position, that are not possible nowadays. The feeding of vortex tubes occurs only with compressed air flow, which can be stored for consumption when necessary. In addition, because of this characteristic, there is the possibility of the kinetic energy reutilizing, that is dissiped to the environment in the braking process currently. This possibility of energetic reutilizing can be made through the transfer of this kinetic energy to the air compressor. Based on this possibility, it was obtained data about the operation of a conventional air conditioning system, besides the energetic regeneration potential data. These data were obtained through technical publications and theoretical calculations. It was established a configuration proposal for the components, as well as the system operation modes. Later, it was made a first selection of the components that have direct influence in the system viability. The results showed the difficulties in the application of this philosophy for light vehicles (passenger cars) with more viability for commercial vehicles use (for example trucks), mainly those vehicles that are equiped with a pneumatic system to the air brakes and air suspension.

O presente trabalho tem por objetivo propor uma metodologia para o dimensionamento da potência tracionária em função do percurso percorrido por veículos elétricos, assim como realizar o projeto básico de uma máquina elétrica para suprir a carga tracionária exigida. Os cálculos foram realizados através de um algoritmo onde o usuário insere as variáveis mecânicas do veículo e recebe a potência e conjugado necessários, e o projeto elementar da máquina que deverá equipar o veículo. Realizou-se um estudo de caso a partir de uma scooter elétrica para validar os resultados, foi projetada uma máquina brushless dc com fluxo radial e rotor externo. Os resultados experimentais atenderam as espectativas de conjugado de 46 Nm, o máximo conjugado estático atingiu 48 Nm e a rotação a vazio obteve valor de 613 rpm à tensão nominal. Os ensaios de frenagem regenerativa com supercapacitores apresentaram resultados promissores com 50% da energia mecânica recebida durante a frenagem entregue na partida do veículo. / The present study aims to propose a methodology for the design of power traction depending on the distance traveled by electrical vehicles, and perform the basic design of an electrical machine to supply the traction load required. The calculations will be performed through an algorithm where the user enters the mechanical variables of the vehicle and receives the power and torque required and the basic machine design that should equip the vehicle. A case study was conducted for an electric scooter considering the designed dc brushless machine with radial flow and external rotor in order to validate the results. The experimental results met the target of 46 Nm of torque, the maximum static torque 48 Nm was reached, and the no-load rotation obtained was 613 rpm at nominal voltage. Regenerative braking tests with super capacitors showed a promising result: 50% of the received mechanical energy during braking was delivered to the vehicle starting.

Este trabalho foi desenvolvido com o objetivo de estudar a aplicação, para sistema de frenagem veicular, de uma máquina elétrica sem escovas, de armadura toroidal, e fluxo magnético axial produzido por ímãs permanentes de terras raras, a chamada máquina Torus. A máquina foi construída no LMEAE e estudada inicialmente como motor em outro trabalho. Mas, para que se possa avaliar seu funcionamento em sistema de frenagem, o foco é do ponto de vista da máquina como gerador. São realizados testes dinâmicos e estáticos experimentalmente e modelo numérico pelo método dos elementos finitos com um formato de ímãs permanentes de seção setorial, possibilitando o comparativo com a versão anterior da máquina que empregou ímãs de seção quadrada. Mudanças físicas e no sistema de acionamento da máquina, e ensaios de frenagem dinâmica foram realizados. Modelagem analítica para indução magnética foi desenvolvida utilizando-se da técnica de Transformação Conforme. O trabalho busca apresentar as características da máquina e justificativas que demonstram o seu potencial de aplicabilidade em um subsistema veicular sob frenagem regenerativa e a capacidade de fornecimento de energia a um sistema de armazenamento com uma parte de energia cinética, ou seja, baterias e supercapacitores. / This work is carried out with the aim to study the application, by a vehicular braking system, of a brushless electrical machine with a toroidal armature core, and axial magnetic flux delivered by rare earth permanent magnets, the so-called Torus machine. The machine was built in the LMEAE, and previously studied as a motor by other work. However, in order to assess its performance in a braking system, the focus is the point of view of the machine as a generator. Static and dynamic tests are implemented as well as a numerical model by means of the finite element method, in order to compare the machine with sector poles permanent magnets and with square magnet poles. Physical changes and on the driving system of the machine, and dynamic braking tests are performed. The analytical modelling for the magnetic induction was developed using the technique of conformal transformation. The study aims to present the features of the machine and demonstrates its potential applicability to a vehicular subsystem under regenerative braking and the ability to supply an energy storage system with part of the kinetic energy, i.e. batteries and super capacitors.