The feasibility of obtaining improved fuel efficiency by incorporating a hydrostatic transmission was investigated. The proposed transmission was composed of positive-displacement axial-piston hydraulic devices. The displacement of the pump and motor units could be varied to allow the prime mover to operate within its most efficient range. A dynamic model representing a Ford Pinto was developed using bond graphs and the IBM CSMP language to simulate the performance of the proposed design. The required input to this program consists of three independent, or control variables. These are the pump and motor swashplate angles and the engine throttle angle. In present form, the output of this program includes instantaneous values of vehicle velocity, pump and motor efficiencies, engine bsfc, and fuel economy. Observations from the simulations indicate that the test vehicle is capable of exceeding the EPA highway fuel economy estimates for the 1978 production Pinto by 11%. This increase in economy is a result of operating the engine near the minimum bsfc. Although comparisons were not made in this study, it is believed that even higher increases in economy may be realized in urban-type periods of operation. / Master of Science

M.S.

This thesis is written with the intention to help establish the fact that there are definite advantages to be claimed from the use of statistical quality control in the foundry industry. / Master of Science

Call number: LD2668 .T4 1979 P32 / Master of Science

Orientador: José Maria Campos dos Santos / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica, Faculdade de Engenharia Eletrica e de Computação e Instituto de Química / Made available in DSpace on 2018-09-11T21:15:54Z (GMT). No. of bitstreams: 1 Pecula_MauroMiguel_M.pdf: 3399170 bytes, checksum: eb3730f4b592d4e1060f9a87cfd2bfe4 (MD5) Previous issue date: 2010 / Resumo: Os requisitos de qualidade sonora estão sendo cada vez mais utilizados no mercado de caminhões médios e pesados. Assim, proprietários de veículos sentem-se incomodados pelo ruído de engrenamento. O estudo do ruído de engrenamento neste trabalho baseia-se em um par engrenado de um motor diesel pesado de aplicação veicular. Como primeiro estudo foi calculado o erro de transmissão das engrenagens por meio das deformações dos dentes sob carga que conforme a literatura a sua amplitude de pico a pico está diretamente relacionada com o ruído de engrenamento. A verificação desta influência foi feita através de medições vibro - acústicas do motor em marcha lenta. Os dados calculados do erro de transmissão e dos sinais medidos foram confrontados obtendo-se convergência. Uma análise de qualidade sonora, por meio de teste de júri, foi realizada para verificar o impacto do ruído de engrenamento na qualidade sonora / Abstract: The requirements of sound quality are increasingly being used in medium and heavy trucks market. Then, owners of vehicles fell troubled by whine noise. The study of whine noise in this thesis is based in one geared pair of a heavy duty diesel engine for vehicular application. As a first approach the transmission error of the gears was calculated by the deformations of the teeth under load (compliance), according to literature, the transmission error peak to peak amplitude, had directly correlation with the whine noise. The proofing of this influence was performed through vibro-acoustics measurements of the engine in low idle. The calculated data of transmission error and processed measurements signals were confronted, obtaining convergence. A sound quality analysis, by juri test, was performed to verify the impact of the whine noise in sound quality / Mestrado / Dinâmica / Mestre em Engenharia Automobilistica

This thesis studies the dynamic model and simulation of a Half-Toroidal (HT) type Continuously Variable Unit (CVU) integrated into a conventional powertrain. A simplified parametric model of a HT-CVU is constructed using Finite Element Method (FEM) in which the continuous variable speed unit is discretized into lumped masses, spring and damper elements. Linearized Finite Elements (FE) have been used to model the contacts between the toroids and rollers. The phenomenon of slip and spin associated with the rolling-slipping contacts of the traction drives are modelled kinematically. All Finite Elements including the CVU model are integrated into the complete powertrain system. Free Vibration Analysis (FVA) of the multi degree of freedom system is carried out for torsional vibration for High Gear (HGR) and Low Gear Ratio (LGR) conditions. Further, FVA is carried out with a lock-up clutch engaged at high speed range. The results of the FVA indicates significant changes in natural frequencies and corresponding mode shapes for both HGR and LGR condition with a change in HT-CVU gear ratios. Change in natural frequencies and mode shapes for both HGR and LGR conditions are also observed for varying contact torsional stiffness. The change is significant till a certain value of contact torsional stiffness. Further increase in contact torsional stiffness within the HT-CVU does not affect the natural frequencies and corresponding mode shapes significantly. The results of the modal analysis carried out for a HT-CVU integrated powertrain with a lock-up clutch engaged at high speed range illustrates the ability of the lock-up clutch to simultaneously suspend engine and roller element excitation. However, for certain natural frequencies the modal analysis of the integrated powertrain system indicates suspension of engine and input toroid but increased excitation for the roller element of the HT-CVU. The transient dynamic analysis is carried out to understand the behaviour of the CVU integrated into the complete powertrain and to identify and possibly correct potential problems associated with the system. The simulation is carried out for constant and variable throttle conditions for the powertrain with and without a lock up clutch engaged at high speed ranges. A piecewise curved gear ratio map is assumed for all conditions. All analyses are carried out for throttle 'tip-in' condition. The results of the transient dynamic analysis indicate that the transient responses of input and output rollers of the HT-CVU exist when clutch change occurs during vehicle acceleration period from stand still condition. The clutch change also leads to disturbances in the HT-CVU output torque to driveline and in vehicle speed. This leads to imperfect drive feel for the driver. The simulated vehicle velocity indicates powerful acceleration characteristics of the HT-CVU integrated powertrain. Engine harmonics is modelled as a rich collection of various forcing frequencies. These frequencies impress on the response of both the roller and output toroid and are observed in the simulation. Stability analysis is carried out on the powertrain to understand the effect of damping in the tyres and damping within the HT-CVU on the stability of the powertrain. Severe or even unstable response of the HT-CVU takes place if the damping in the HT-CVU and/or the tyres is insufficient during the initial acceleration period and later after the clutch change occurs and when the vehicle is at high speeds. The results of the stability analysis lead us to reason with confidence that the tyre and HT-CVU damping have an effect on the dynamic characteristics and the stability of the system. The response of the powertrain becomes stable when a lock-up clutch is applied over the high speed ranges even if the damping in the tyres remains insufficient. The modal damping ratios for stable and unstable conditions are also discussed. Future investigations need to be carried out in order to understand in depth the fluid-metal interaction in the HT-CVU. This can be achieved by modelling in non-linear drag torque which would act on the HT-CVU elements.

No description available.

This thesis studies the dynamic model and simulation of a Half-Toroidal (HT) type Continuously Variable Unit (CVU) integrated into a conventional powertrain. A simplified parametric model of a HT-CVU is constructed using Finite Element Method (FEM) in which the continuous variable speed unit is discretized into lumped masses, spring and damper elements. Linearized Finite Elements (FE) have been used to model the contacts between the toroids and rollers. The phenomenon of slip and spin associated with the rolling-slipping contacts of the traction drives are modelled kinematically. All Finite Elements including the CVU model are integrated into the complete powertrain system. Free Vibration Analysis (FVA) of the multi degree of freedom system is carried out for torsional vibration for High Gear (HGR) and Low Gear Ratio (LGR) conditions. Further, FVA is carried out with a lock-up clutch engaged at high speed range. The results of the FVA indicates significant changes in natural frequencies and corresponding mode shapes for both HGR and LGR condition with a change in HT-CVU gear ratios. Change in natural frequencies and mode shapes for both HGR and LGR conditions are also observed for varying contact torsional stiffness. The change is significant till a certain value of contact torsional stiffness. Further increase in contact torsional stiffness within the HT-CVU does not affect the natural frequencies and corresponding mode shapes significantly. The results of the modal analysis carried out for a HT-CVU integrated powertrain with a lock-up clutch engaged at high speed range illustrates the ability of the lock-up clutch to simultaneously suspend engine and roller element excitation. However, for certain natural frequencies the modal analysis of the integrated powertrain system indicates suspension of engine and input toroid but increased excitation for the roller element of the HT-CVU. The transient dynamic analysis is carried out to understand the behaviour of the CVU integrated into the complete powertrain and to identify and possibly correct potential problems associated with the system. The simulation is carried out for constant and variable throttle conditions for the powertrain with and without a lock up clutch engaged at high speed ranges. A piecewise curved gear ratio map is assumed for all conditions. All analyses are carried out for throttle 'tip-in' condition. The results of the transient dynamic analysis indicate that the transient responses of input and output rollers of the HT-CVU exist when clutch change occurs during vehicle acceleration period from stand still condition. The clutch change also leads to disturbances in the HT-CVU output torque to driveline and in vehicle speed. This leads to imperfect drive feel for the driver. The simulated vehicle velocity indicates powerful acceleration characteristics of the HT-CVU integrated powertrain. Engine harmonics is modelled as a rich collection of various forcing frequencies. These frequencies impress on the response of both the roller and output toroid and are observed in the simulation. Stability analysis is carried out on the powertrain to understand the effect of damping in the tyres and damping within the HT-CVU on the stability of the powertrain. Severe or even unstable response of the HT-CVU takes place if the damping in the HT-CVU and/or the tyres is insufficient during the initial acceleration period and later after the clutch change occurs and when the vehicle is at high speeds. The results of the stability analysis lead us to reason with confidence that the tyre and HT-CVU damping have an effect on the dynamic characteristics and the stability of the system. The response of the powertrain becomes stable when a lock-up clutch is applied over the high speed ranges even if the damping in the tyres remains insufficient. The modal damping ratios for stable and unstable conditions are also discussed. Future investigations need to be carried out in order to understand in depth the fluid-metal interaction in the HT-CVU. This can be achieved by modelling in non-linear drag torque which would act on the HT-CVU elements.

The purpose of this thesis is the construction of a test bench for the assessment of the NVH behaviour of a newly manufactured VW Polo 5. This will be done in collaboration with Volkswagen South Africa. Firstly, in order to gain a better understanding of the requirements such a test bench has to fulfill, the VW Polo, the guidelines prescribed by VW as well as the actual testing procedure implemented by VW Uitenhage will be analysed. Thereafter, the main section of the thesis will deal with the construction of the test bench. As agreed upon with Volkswagen Uitenhage, a test bench will be built during the course of the studies. This test bench will allow stimulation in low frequency as well as high frequency ranges and in addition to that, a second version of the test bench with optimised costing will be derived from the first one. The second model will only allow stimulation in high frequency ranges. During the thesis, a version of the test bench, the RTB-HC, has been developed which enables the stimulation of the high and low frequencies. In addition, a cost optimized version was developed. This version will be referred as RTB-LC. This version allows only a high frequency excitation.

Call number: LD2668 .T4 1984 B58 / Master of Science