A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1996. / This research project is an investigation into the effectiveness of an inspect and rework system called dynamic section control which has the purpose of improving the assembly quality of the BMW-3 series manufacturing in the Rosslyn Plant just outside Pretoria in South Africa, The system was introduced into the assembly plant in February 1995 to improve the assembly quality of the vehicles as quickly as possible. The main motivation behind the need for this system was to bring the quality onto the same level as the German plants in order to become recognised in the international network of BMW's manufacturing plants along with the new manufacturing plant in the USA The origins of the dynamic section control system come from the Munich 3-series plant as well as being based on the principles of poka yoke, a quality philosophy devised by the quality expert from Toyota in Japan, Shigeo Shingo, Defects found on the assembly plant's line, identified by the quality auditor and information from the marketing department regarding warranty claims are entered onto a checklist which is used by reworkers in the plant to inspect and make good the defects that have been found. The checklist is updated on a weekly basis, hence its name: dynamic section control. Seven rework stations, in which the dynamic section control reworkers work, have been strategically positioned in the assembly plant which trims the painted bodies it receives from the paint shop, The effectiveness of the system has been measured by analysing the information from the daily audits as well as investigating the trend of vehicles If rving the assembly plant still requiring rework and repairs off-line. The analyses were divided into three distinct periods. The first being approximately 4 months before the introduction of :he dynamic section control system, and the second and third periods after the introduction of the system. The results show that the dynamic section control system have a positive influence in improving the assembly quality of the vehicles, especially reducing the number of recurring defects. The number of defects that have only occurred once in each of the periods has remained reasonably constant indicating that the system has no impact in reducing the random occurrence of "one-off" defects. Another significant finding was. the increase in the number of vehicles requiring Department of Mechanical Engineering, University of the Witwatersrand repair off-line, attributable to the assembly plant, after the vehicle has left the assembly line. This increase is probably the result of an increased quality awareness within the assembly plant, resulting in reworkers identifying an increasing number of defects for repair off-line. Other factors such as clearer identification of production goals, training and development of a proportion of the assembly plant's workers in the German plants lor three weeks, reorganizing of support. staff by installing "the right people in the right place" and reducing the number of model derivatives in the plant have also contributed to the enormous quality improvement achieved. Further development of the. dynamic section control system is recommended by installing a rework station within each team area, and including the actions of dynamic section control in the work content of that team. Currently, the system uses external workers which are not part of individual teams as the current sections overlap team areas. Finally, it is recommended that the work of the dynandc section control reworker be incorporated as a noma! function within the team and be rotated amongst the team members. / AC2017

Orientador: Milton Dias Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T18:54:27Z (GMT). No. of bitstreams: 1 Miyasato_HugoHeidy_M.pdf: 3357683 bytes, checksum: 9fcd8bd237500580084498c606879165 (MD5) Previous issue date: 2011 / Resumo: Fenômenos de ruído, vibração e sua severidade (NVH) são uma grande preocupação da indústria automotiva desde o século 20. A fim de atingir uma vantagem competitiva, as montadoras têm se focado na melhora do desempenho de NVH dos seus produtos para lidar com um cenário de mercado global competitivo. No intuito de verificar o comportamento do sistema durante o processo de desenvolvimento, métodos computacionais são aplicados para encontrar melhores abordagens e na previsão de problemas, economizando tempo e orçamento da empresa gastos na construção de protótipos e testes. Nesse trabalho, gear rattle, um ruído induzido por impacto cuja causa são as engrenagens sem carga da transmissão, será modelado e simulado. É diagnosticado com maior intensidade em veículos com motores diesel em marcha lenta e excitado especificamente quando uma faixa de frequências que causa grande amplitude de vibração nos elementos internos da caixa de câmbio é alcançada. Modelos lineares do trem de potência em ponto morto ou em tração serão estudados, compreendendo as suas características básicas, tais como frequências naturais e modos associados que podem ser representativos do fenômeno. Esse sistema possui elementos com fortes não-linearidades, tais como a rigidez estratificada com histerese da embreagem e a folga entre os dentes dos engrenamentos. Uma caracterização mais realista será incluída no modelo com uma rigidez variante no tempo para o engrenamento helicoidal, utilizado em todas transmissões manuais, com uma componente dissipativa adequada aos impactos. Para verificar condições de operação que podem somente ser avaliadas segundo formulação não-linear, simulações serão realizadas para verificar a eficácia de orientações de solução e propostas de modificação encontradas na literatura / Abstract: Noise, Vibration and Harshness (NVH) phenomena are a great concern of the automotive industry since the twentieth century. In order to achieve a commercial advantage, manufacturers have focused on improving the NVH performance of their products to cope with a competitive global market scenario. To verify the behavior of the system during the design process, computational methods are applied to find a better approach and foresee problems, saving company budget and time spent in prototypes and tests. In this work, gear rattle, a impact-induced noise caused by the unloaded gear teeth inside the gearbox, will be modeled and simulated. It is diagnosed with a higher intensity in diesel vehicle engines at idle speed and in a more specific way excited when a range of frequency that causes large amplitude of vibration in the internal elements of the gearbox is reached. Linear models of the powertrain operating in idle and traction will be studied, in order to understand its basic characteristics, such as natural frequencies and associated vibration modes that could be representative to this phenomena. This system has elements with strong nonlinearities such as the stratified stiffness with hysteresis of the clutch and the backlash between the gear teeth. A more realistic feature will be included in the model with a time variable stiffness for the helical gear mesh, used in all manual transmissions, with a suitable dissipative component for the impacts. To verify operational conditions which can only be evaluated with nonlinear formulation, simulations will be made to verify the effectiveness of solution guidelines and modification procedures found in literature / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientador: Milton Dias Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-22T19:22:01Z (GMT). No. of bitstreams: 1 RoldaoPerestrelo_LeandroTadeu_M.pdf: 15158370 bytes, checksum: 84a10bb14b3381b619db8ff9bb97be9c (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

In this dissertation, a group of vehicle dynamics simulation tools is developed with two primary goals: to accurately represent vehicle behavior and to provide insight that improves the understanding of vehicle performance. Three tools are developed that focus on tire modeling, vehicle modeling and lap time simulation. Tire modeling is based on Nondimensional Tire Theory, which is extended to provide a flexible model structure that allows arbitrary inputs to be included. For example, rim width is incorporated as a continuous variable in addition to vertical load, inclination angle and inflation pressure. Model order is determined statistically and only significant effects are included. The fitting process is shown to provide satisfactory fits while fit parameters clearly demonstrate characteristic behavior of the tire. To represent the behavior of a complete vehicle, a Nondimensional Tire Model is used, along with a three degree of freedom vehicle model, to create Milliken Moment Diagrams (MMD) at different speeds, longitudinal accelerations, and under various yaw rate conditions. In addition to the normal utility of MMDs for understanding vehicle performance, they are used to develop Limit Acceleration Surfaces that represent the longitudinal, lateral and yaw acceleration limits of the vehicle. Quasi-transient lap time simulation is developed that simulates the performance of a vehicle on a predetermined path based on the Limit Acceleration Surfaces described above. The method improves on the quasi-static simulation method by representing yaw dynamics and indicating the vehicle's stability and controllability over the lap. These improvements are accomplished while maintaining the simplicity and computational efficiency of the two degree of freedom method. / Graduation date: 2013

This work presents an investigation into the parameter estimation of suspension components and the vertical motions of wheeled vehicles from experimental data. The estimation problems considered were for suspension dampers, a single wheel station and a full vehicle. Using conventional methods (gradient-based (GB), Downhill Simplex (DS)) and stochastic methods (Genetic Algorithm (GA) and Differential Evolution (DE)), three major problems were encountered. These were concerned with the ability and consistency of finding the global optimum solution, time consumption in the estimation process, and the difficulties in setting the algorithm's control parameters. To overcome these problems, a new technique named the discrete variable Hybrid Differential Evolution (dvHDE) method is presented. The new dvHDE method employs an integer-encoding technique and treats all parameters involved in the same unified way as discrete variables, and embeds two mechanisms that can be used to deal with convergence difficulties and reduce the time consumed in the optimisation process. The dvHDE algorithm has been validated against the conventional GB, DS and DE techniques and was shown to be more efficient and effective in all but the simplest cases. Its robustness was demonstrated by its application to a number of vehicle related problems of increasing complexity. These include case studies involving parameter estimation using experimental data from tests on automotive dampers, a single wheel station and a full vehicle. The investigation has shown that the proposed dvHDE method, when compared to the other methods, was the best for finding the global optimum solutions in a short time. It is recommended for nonlinear vehicle suspension models and other similar systems.

This work presents an investigation into the parameter estimation of suspension components and the vertical motions of wheeled vehicles from experimental data. The estimation problems considered were for suspension dampers, a single wheel station and a full vehicle. Using conventional methods (gradient-based (GB), Downhill Simplex (DS)) and stochastic methods (Genetic Algorithm (GA) and Differential Evolution (DE)), three major problems were encountered. These were concerned with the ability and consistency of finding the global optimum solution, time consumption in the estimation process, and the difficulties in setting the algorithm's control parameters. To overcome these problems, a new technique named the discrete variable Hybrid Differential Evolution (dvHDE) method is presented. The new dvHDE method employs an integer-encoding technique and treats all parameters involved in the same unified way as discrete variables, and embeds two mechanisms that can be used to deal with convergence difficulties and reduce the time consumed in the optimisation process. The dvHDE algorithm has been validated against the conventional GB, DS and DE techniques and was shown to be more efficient and effective in all but the simplest cases. Its robustness was demonstrated by its application to a number of vehicle related problems of increasing complexity. These include case studies involving parameter estimation using experimental data from tests on automotive dampers, a single wheel station and a full vehicle. The investigation has shown that the proposed dvHDE method, when compared to the other methods, was the best for finding the global optimum solutions in a short time. It is recommended for nonlinear vehicle suspension models and other similar systems.

Brand personality is a set of human personality traits that are relevant to a brand. A distinctive brand personality serves a symbolic or self-expressive function and helps to create a set of unique and favourable associations in the consumer’s mind. Generation Y consumers are considerably more brand and image conscious than any other generational cohort. Given that motor vehicles, especially luxury motor vehicles, are a conspicuous consumption item that are often used to signal status to others, luxury motor vehicle marketers need to understand Generation Y members’ perceptions of brand personality. Aaker (1997) developed a brand personality trait scale to measure brand personality perceptions. This study established a factor structure for Aaker’s (1997) brand personality trait scale applicable for luxury sedan brands. This adapted brand personality trait scale was used to investigate the brand personality perceptions of luxury sedan motor vehicles amongst Generation Y. The target population for this study was defined as students registered at South Africa’s public HEIs in 2014. This study made use of a non-probability convenience sample to select one traditional university campus and one university of technology campus located in the Gauteng province of South Africa. Self-administered questionnaires were distributed in two separate steps. Step 1 of the study distributed the questionnaire to 65 participants to identify Generation Y students’ top-of-the-mind awareness concerning luxury sedan motor vehicle brands. Step 2 of the study distributed 500 questionnaires to investigate the brand personality perceptions of luxury sedan brands amongst Generation Y students by means of Aaker’s (1997) brand personality trait scale. Step 2 also investigated Generation Y students’ purchasing intentions of luxury sedan motor vehicles by making use of an adapted a scale by Zeithaml et al. (1996:31-46). The statistical analysis included exploratory factor analysis, descriptive statistical analysis and significance tests. The findings of the study suggest that Generation Y students’ top three luxury sedan brands are BMW, Mercedes-Benz and Audi. The brand personality perception results revealed that all three brands are associated with the ‘Competence’ and ‘Sophisticated’ brand personality dimensions. In addition, BMW is also associated with the ‘Excitement’ brand personality dimension. The findings of the study also suggest that Generation Y students do have purchasing intentions of luxury sedan motor vehicles. Some gender differences regarding Generation Y students’ brand personality perceptions and purchasing intentions of luxury sedan motor vehicles do exist. However, the differences are limited with a small effect of practical significance. The study offers insight into the brand personality perceptions in the South African market. Generation Y consumers have unique perceptions regarding different brands and it is therefore important to gain insight regarding their perceptions. The results presented in this study can aid the marketers of the selected luxury sedan motor vehicle brands in identifying the personality traits associated with their brand. This information can be compared with their current marketing strategy to determine if any differences exist between the desired and perceived brand personality. This can also help the marketers to tailor the marketing strategy accordingly to achieve the desired brand personality / MCom (Marketing Management)--North-West University, Vaal Triangle Campus, 2015

Brand personality is a set of human personality traits that are relevant to a brand. A distinctive brand personality serves a symbolic or self-expressive function and helps to create a set of unique and favourable associations in the consumer’s mind. Generation Y consumers are considerably more brand and image conscious than any other generational cohort. Given that motor vehicles, especially luxury motor vehicles, are a conspicuous consumption item that are often used to signal status to others, luxury motor vehicle marketers need to understand Generation Y members’ perceptions of brand personality. Aaker (1997) developed a brand personality trait scale to measure brand personality perceptions. This study established a factor structure for Aaker’s (1997) brand personality trait scale applicable for luxury sedan brands. This adapted brand personality trait scale was used to investigate the brand personality perceptions of luxury sedan motor vehicles amongst Generation Y. The target population for this study was defined as students registered at South Africa’s public HEIs in 2014. This study made use of a non-probability convenience sample to select one traditional university campus and one university of technology campus located in the Gauteng province of South Africa. Self-administered questionnaires were distributed in two separate steps. Step 1 of the study distributed the questionnaire to 65 participants to identify Generation Y students’ top-of-the-mind awareness concerning luxury sedan motor vehicle brands. Step 2 of the study distributed 500 questionnaires to investigate the brand personality perceptions of luxury sedan brands amongst Generation Y students by means of Aaker’s (1997) brand personality trait scale. Step 2 also investigated Generation Y students’ purchasing intentions of luxury sedan motor vehicles by making use of an adapted a scale by Zeithaml et al. (1996:31-46). The statistical analysis included exploratory factor analysis, descriptive statistical analysis and significance tests. The findings of the study suggest that Generation Y students’ top three luxury sedan brands are BMW, Mercedes-Benz and Audi. The brand personality perception results revealed that all three brands are associated with the ‘Competence’ and ‘Sophisticated’ brand personality dimensions. In addition, BMW is also associated with the ‘Excitement’ brand personality dimension. The findings of the study also suggest that Generation Y students do have purchasing intentions of luxury sedan motor vehicles. Some gender differences regarding Generation Y students’ brand personality perceptions and purchasing intentions of luxury sedan motor vehicles do exist. However, the differences are limited with a small effect of practical significance. The study offers insight into the brand personality perceptions in the South African market. Generation Y consumers have unique perceptions regarding different brands and it is therefore important to gain insight regarding their perceptions. The results presented in this study can aid the marketers of the selected luxury sedan motor vehicle brands in identifying the personality traits associated with their brand. This information can be compared with their current marketing strategy to determine if any differences exist between the desired and perceived brand personality. This can also help the marketers to tailor the marketing strategy accordingly to achieve the desired brand personality / MCom (Marketing Management)--North-West University, Vaal Triangle Campus, 2015

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006. / The quest for higher efficiency of the internal combustion engine will always be pursued. Increasingly stringent emission regulations are forcing manufacturers to downsize on engine displacement and increase specific power. By adding a turbocharger, the airflow throught he engine and hence the specific power can be increased.

Vehicle Satellite Navigation Systems are commonplace but from a safety point of view, can be problematic. They are situated on small screens and often placed at an angle which is not in the driver’s field of view. This promotes glances away from the road and reduces situational awareness for events which occur. Audio commands and visual maps which are used to instruct drivers typically require translation to situationally meaningful actions before execution in the real world. This increases the driver’s workload and risk of distraction. A virtual car head-up display concept which is novel to this thesis is introduced. The design was motivated by issues in the literature regarding workload and risk of distraction and was shaped using a field study. Also, as head-up displays are becoming common in new vehicles, the benefits they offer have been explored in the design of the virtual car head-up display. Navigation instructions would be embedded in a familiar object to the driver; a car image, to support driving practices (e.g. indicating, lane positioning and turning) which are absent in the abstract commands and visual maps employed by vehicle satellite navigation systems. The navigation instructions used by the virtual car head-up display are easy to understand and can reduce the processing times for the instructions. For example, rather than translate audio commands e.g. “after 200 yards turn left”, the driver sees the virtual car indicate left 200 yards from the turn and sees it turn left on arrival at the turn. Also, rather than translate complex visual maps, the driver replicates the actions of the virtual car. An initial prototype for the virtual car head-up display was designed after which usability evaluation was carried out in a driving simulator to refine the concept. The first two studies were part of the design process and involved assessing the feasibility and conformity of the virtual car head-up display. It was found that the virtual car head-up display was an intelligible way to present the navigation instructions to drivers and that it was better to conform the virtual car to the external environment. The third study compared the prototype of the virtual car head-up display with the prototype of an arrow head-up display and vehicle satellite navigation system. It was found that the virtual car head-up display had the least workload and risk of distraction and was the easiest to use. A synthesis of the research work is provided which outlines the key contributions to research.