Experimental analysis of disc thickness variation development in motor vehicle brakes

Over the past decade vehicle judder caused by Disc Thickness Variation (DTV) has become of major concern to automobile manufacturers worldwide. Judder is usually perceived by the driver as minor to severe vibrations transferred through the chassis during braking [1-9]. In this research, DTV is investigated via the use of a Smart Brake Pad (SBP). The SBP is a tool that will enable engineers to better understand the processes which occur in the harsh and confined environment that exists between the brake pad and disc whilst braking. It is also a tool that will enable engineers to better understand the causes of DTV and stick-slip the initiators of low and high frequency vibration in motor vehicle brakes. Furthermore, the technology can equally be used to solve many other still remaining mysteries in automotive, aerospace, rail or anywhere where two surfaces may come in contact. The SBP consists of sensors embedded into an automotive brake pad enabling it to measure pressure between the brake pad and disc whilst braking. The two sensor technologies investigated were Thick Film (TF) and Fibre Optic (FO) technologies. Each type was tested individually using a Material Testing System (MTS) at room and elevated temperatures. The chosen SBP was then successfully tested in simulated driving conditions. A preliminary mathematical model was developed and tested for the TF sensor and a novel Finite Element Analysis (FEA) model for the FO sensor. A new method called the Total Expected Error (TEE) method was also developed to simplify the sensor specification process to ensure consistent comparisons are made between sensors. Most importantly, our achievement will lead to improved comfort levels for the motorist

NA

http://www.archive.org/details/analysisofapplic00frosU.S. Navy (U.S.N.) authors

Dry Clutch Modeling, Estimation, and Control

A Doctor’s degree comprises 240 ECTS credits (4 years of full-time postgraduate studies), of which at least 120 ECTS credits constitute a doctoral dissertation

Dry clutch for automated manual transmissions. Structural analysis and control strategies

2012 - 2013The goal of this thesis is the study of the automotive push-type dry clutches used in the Automatic Manual Transmissions (AMTs) and in the Dual Clutch Transmissions (DCTs) in order to improve their performances dur- ing the engagements phases. The push-type clutch is very widespread in the automotive sector because it allows many advantages in terms of cost, relia- bility, isolation of vibrations to the driveline, reduced axial size and stability to the facings wear [1]. Instead, the main advantages of an AMT, respect to the Automatic Transmissions (ATs), are improvements in terms of safety, reliability, and driving performances together with the reduction of the fuel consumption and pollutant emissions [2]. For these reasons by mixing the advantages of the push-type clutch with the advantages of the AMT it is possible to attain very high performance [3, 4]. On the other hand, the most important drawback of the AMT is the power interruption (the so called "torque gap") during the gear shifts events. To solve this problem in the last decade the DCTs have been introduced. In fact, by applying the engine torque to one clutch just as the engine torque is being disconnected from the other one [5] the torque transmission is allowed also during the gear shift phases. In this light, the work developed for this Thesis aimed at providing useful information both to the clutch designers and to control algorithm designers in order to enhance the performances, and consequently, the market di usion mof the AMT and DCT transmissions. The thesis is organized as follows. Chapter 2 is an introductory section on the historical evolution of the clutches and of the automotive transmissions systems. Chapter 3 deals with the transmissibility torque model by consid- ering the main factors which a ect the elastic components of a push-type clutch and the friction coe cient. In the Chapter 4 application of control algorithms both for a two DoFs driveline model and for a ve DoFs model are introduced. Finally, the Chapter 5 underlines the concluding remarks. [edited by author]XII n.s

Contribution to the validation and verification of drive-neutral-reverse subsystem of a CVT transmission

Continuously Variable Transmissions (CVT) are the synonymous for fuel economy and smooth ride. Due to these major features of this type of automatic transmission (AT) it can be easily the future of automatic transmissions since the restrictions regarding to the fuel emissions are getting stricter. The knowledge by the student related to this thematic was developed in an internship with a duration of six months at a specialized company in the development and production of CVT transmissions. By being incorporated in the department of R&D, specifically on the team of the DNR subsystem (Drive‐Neutral‐Reverse subsystem), it was possible to be introduced to CVT. Punch Powertrain NV in Belgium, Sint‐Truiden, was the perfect opportunity to enrich the academic experience of the student, to introduce the student to development field of automotive transmissions industry from concept to testing and also to consolidate the experience in the automotive industry previously started at Simoldes Plásticos during the master degree. Firstly, it was suggested to assist to the prototype assembly process of a complete CVT followed by the analyses to the flow chart of the DNR subsystem and the manufacturability of all the components of the subsystem in order to get introduced to the subsystem. Secondly it was proposed to develop a showcase model which would be a great tool to explain people the working principle of a DNR subsystem in detail. At the same time, the student decided to start some calculations related to the DNR subsystem not only to better understand the subsystem and apply the knowledge obtained during the graduation but also to learn more specific subjects related to this field of study. This task would later allow the student to verify the mechanical requirements. After asking for quotations and getting in contact with several suppliers it was time to assemble the entire showcase getting in contact with different manufacturing processes and difficulties. At the end, it is irrefutable the amount of knowledge acquired during the internship. Undoubtedly, the support from all the colleagues was very important by transmitting me all their knowledge and experience.Transmissões Continuamente Variáveis (CVT) são sinónimo de economia de combustível e condução suave. Devido a estas grandes características deste tipo de transmissão, podemos estar facilmente perante o futuro das transmissões automáticas visto que as restrições relativamente às emissões de combustível se estão a tornar mais apertadas. O conhecimento adquirido pelo estudante nesta temática foi desenvolvido num estágio com duração de seis meses numa empresa especializada no desenvolvimento e produção de transmissões CVT. Ao estar incorporado no departamento de I&D, mais especificamente na equipa de desenvolvimento do subsistema DNR, foi possível familiarizar‐se com as Transmissões de Continuamente Variáveis. Punch Powertrain NV na Bélgica, Sint‐Truiden, foi a oportunidade perfeita para enriquecer a experiência do estudante, introduzi‐lo à área de desenvolvimento da indústria das transmissões automóveis desde o conceito até à fase de testes, e também para consolidar a experiência na indústria automóvel previamente iniciada num estágio na Simoldes Plásticos durante o percurso de mestrado. Em primeiro lugar, foi sugerido assistir à montagem da fase protótipo de uma CVT seguida da análise do esquema do fluxo do óleo do subsistema DNR e os processos de fabrico de todos os componentes do subsistema com vista a integrar‐se no subsistema. Em segundo lugar foi proposto desenvolver um equipamento de amostra que seria uma ótima ferramenta para explicar detalhadamente às pessoas o princípio de funcionamento de um subsistema DNR. Ao mesmo tempo, o estudante decidiu começar alguns cálculos relativos ao subsistema DNR não só para melhor compreender o subsistema, mas também para aplicar o conhecimento adquirido durante o seu percurso académico com vista a aprender campos mais específicos sobre este tema de estudo. Esta tarefa iria mais tarde permitir ao estudante a verificação dos requisitos. Após de alguns pedidos de orçamentação e de ter entrado em contacto com alguns fornecedores, era tempo da montagem do equipamento de amostra estando diretamente em contacto com diferentes processos de fabrico e respetivas dificuldades. No final, é irrefutável a proporção de conhecimento adquirido durante este estágio. Sem dúvida alguma o apoio dos colegas foi bastante importante ao transmitirem todo o seu conhecimento e experiência

Design of plant for extrusion of pigment pastes

In the light of the requirement for a controllable and reliable extrusion plant for preforming various types of inorganic pigment into spaghetti shape onto a convective band dryer to facilitate drying, a study of the preforming method currently in use by the sponsors has revealed that the screw extruder being used cannot perform this function satisfactorily. The main reason being the thixotropic nature of the pigments. They do not readily tolerate mixing or working, which is inherent in the screw extruder. This necessitated a study of other preforming methods. The thesis reviews the available methods of preforming, existing theories on extrusion of material, and various extruder concepts generated during the initial stages of the project. The concept chosen is discussed. A mathematical model based on test results carried out on a Laboratory model of the chosen extruder concept and tile complete design of the full scale extrusion machine, together with its charging units and the plants' control system is presented. An analysis of the performance tests carried out on the new plant is discussed. The thesis concludes with a comparison between the new plant and the screw extruder in current use regarding their performances and product qualities. Proposals for further work and test are also made