Characteristics Analysis of Non-linear Torsional Vibration in Engine and Generator Shafting system

To solve the non-linear torsional vibration problem of engine and generator shafting causing body structural vibration and noise in motorized wheel vehicle, where the engine and the generator connected directly. First of all, analysis the characteristics of the shafting system, besides the external shock excitation of engine and generator. Then, through lumped parameter model method, mathematical model of the non-linear torsional vibration was established, which could reflect the dynamic characteristics of the system. Analysis the effect of mechanical parameters and electromagnetic parameters on the shafting. And get the non-linear differential equations of the system torsional vibration, which expresses the relation between structural parameters, electromagnetic parameters and the system dynamic characteristics. And multiple scales method was used to solve the equations. Non-contact measurement method was used in the torsional vibration test. Finally, consistency of the results, indicate that the research method used is reliability and accuracy, and get the critical speed of the shafting torsional vibration

Powertrain dynamics and control of a two speed dual clutch transmission for electric vehicles

© 2016 Elsevier Ltd The purpose of this paper is to demonstrate the application of torque based powertrain control for multi-speed power shifting capable electric vehicles. To do so simulation and experimental studies of the shift transient behaviour of dual clutch transmission equipped electric vehicle powertrains is undertaken. To that end a series of power-on and power-off shift control strategies are then developed for both up and down gear shifts, taking note of the friction load requirements to maintain positive driving load for power-on shifting. A mathematical model of an electric vehicle powertrain is developed including a DC equivalent circuit model for the electric machine and multi-body dynamic model of the powertrain system is then developed and integrated with a hydraulic clutch control system model. Integral control of the powertrain is then performed through simulations on the develop powertrain system model for each of the four shift cases. These simulation results are then replicated on a full scale powertrain test rig. To evaluate the performance of results shift duration and vehicle jerk are used as metrics to demonstrate that the presented strategies are effective for shift control in electric vehicles. Qualitative comparison of both theoretical and experimental results demonstrates reasonable agreement between simulated and experimental outcomes

Research of two speed DCT electric power-train and control system

University of Technology Sydney. Faculty of Engineering and Information Technology.The research for this thesis is based on an international cooperation project with BAIC Motor Electric Vehicle Co. Ltd, UTS and AVL/NTC. It aims to develop a sample of a two speed DCT used in an electric drive system. For the dual clutch’s structural characteristics, one clutch is connected with one gear, so it is very simple to realize two speed driving. Simulation models are built in a co-simulation platform using AMESim and Simulink. Gear ratio selection is processed during the matching of Q60FB and C70GB vehicles. The ratios selected are 2nd and 3rd gear, and the ratios are 8.45 and 5.36. The prototype is modified from a VW 6spd DCT to operate at 2 speeds. The work primarily involves modification of the mechanical part of the gears and shaft, and changing the hydraulic parts. To optimize vehicle dynamics and economic performance, a shifting schedule calculation method for PEVs is provided. This uses a graphical development method and is adapted for the purposes of simulations and experimental work. As long as gear shifts are initiated according to the schedule, the EM will be maintained at a higher efficiency operating region. As a result, the proposed method provides more efficient operations of the PEV. Study of the control algorithm, including the vehicle control algorithm and shift control algorithm, is the core of this thesis. To investigate shift control and its calibration of a two speed DCT electric drive power-train, this thesis analyzes the shifting process. The vehicle control algorithm section follows the judgment of the pure electric multimode algorithm. The shift control section analyses the traditional DCT control shifting algorithm. In addition, the shifting control algorithm is based on motor active braking control. Detailed shifting control algorithms are developed which include power-on and power-off methods. Corresponding simulation analysis has also been carried out. The rig test uses the UTS power-train test bench for the purposes of modification. Calibration and testing works are employed for processing and the test rig mainly calibrates the shift control algorithm, DCT temperature testing, and NEDC and UDDS drive cycles testing. Vehicle integration and testing are finished at BJEV. This is based on the BAIC independent brand car of Q60FB, with two gear DCT prototype mounting and road test calibration. Finally, the project tests dynamic and economic performance

A review study on energy harvesting systems for vehicles

The widespread and increasing consumption of fossil-based fuels as an energy source causes a rapid decrease of these natural sources, as well as an increase of pollution in the atmosphere. Fuel oil, one of the products of fossil fuels, is today the commonly used energy source for transportation. The importance of contributing to the fuel economy and of increasing environmental consciousness have necessitated certain measures in the automotive sector, as well as in other industrial sectors. Therefore, the technological developments recently carried out in the automotive sector aim to reduce the consumption of fossil fuels, for example by recovering waste energy in vehicles. In this direction, efforts have been centered upon the development of energy harvesting systems that provide energy recovery from dynamic parts of the vehicles, such as suspensions. Moreover, the regenerative braking systems that recover some amount of kinetic energy of the vehicles slowing down have been developed and have been in use long since. In this study, research studies on providing the recovery of the vehicles’ waste energy are reviewed with their comparisons

O uso de pêndulos centrífugos para controle de vibrações torcionais em trens de potência automotivos

Orientador: Milton Dias JuniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: Absorvedores de Vibração Pendulares Centrífugos (ou CPVAs) são uma tecnologia criada em 1911, que trouxe excelentes resultados na redução de vibração torcional de muitos sistemas. Porém, sua aplicação em trens de potência automotivos para redução de vibração no virabrequim tornou-se inviável ao final da década de 1940 pela existência de dampers viscosos à base de silicone, uma solução mais barata e com performance similar em certas aplicações. Contudo, a vibração torcional transmitida a transmissões manuais ou automatizadas, em certas velocidades críticas, pode gerar ruído em níveis inaceitáveis, e as soluções atuais para a atenuação deste tipo de vibração, em algumas aplicações, são ou pouco efetivas, como o atrito em discos de embreagem, ou muito custosas, como volantes de dupla massa. Por isso, neste trabalho busca-se a aplicação de absorvedores de vibração pendulares em um disco de embreagem de um trem de potência automotivo equipado com uma transmissão automatizada para a redução de vibração torcional na transmissão, reduzindo possivelmente o ruído de rattle. Para este fim, primeiramente testes são realizados no veículo em estudo para o levantamento de dados torcionais do trem de potência, e em seguida, um modelo linear torcional é proposto, para que a dinâmica torcional do trem de potência seja representada. Em seguida, uma análise extensiva dos principais tipos de CPVA é realizada. São realizadas análises lineares e não lineares em modelos com parâmetros adimensionais de um e dois rotores com pêndulos centrífugos, e nas análises não lineares, o Método de Múltiplas Escalas é utilizado; um método mais robusto e preciso do que o método que vem sendo utilizado nos principais trabalhos nesta área. Além disso, as análises são feitas considerando-se que os pêndulos possuem trajetória genérica, e ênfase é dada às trajetórias clássicas: circular, cicloide e epiciclóide. Com base nestas análises, duas metodologias de projeto de pêndulos centrífugos são propostas. Além disso, um protótipo de disco de embreagem com pêndulo é proposto. Então, baseando-se nas limitações do projeto, simulações são feitas utilizando o modelo proposto para o trem de potência e o modelo não linear do pêndulo. As primeiras simulações são feitas obedecendo as limitações do projeto, que propiciam um pequeno raio de instalação do pêndulo e permitem que ele possua massa muito menor do que o valor ideal. Estas simulações mostram que, neste caso o pêndulo se torna instável e ineficaz. Nas simulações seguintes, as limitações de projeto são desprezadas e ambos os projetos de pêndulo são testados. Com maior inércia, o absorvedor pendular é capaz de reduzir substancialmente a vibração torcional na transmissão sem que seja necessário introduzir atrito no disco de embreagem. Contudo, pêndulos com maior inércia podem comprometer a vida útil dos sincronizadores da transmissão, e por isso estudos devem ser realizados para verificar este efeito colateralAbstract: Centrifugal Pendulum Vibration Absorbers (or CPVAs) are a technology which dates back to 1911, and which has brought excellent results on the reduction of torsional vibrations in many systems. Its application in automotive powertrains for the reduction of vibration on the crankshaft became impracticable by the second half of the 1940s due to the existence of silicone based viscous dampers, a cheaper solution that had similar performance in many applications. However, torsional vibration transmitted to manual or semi-automatic gearboxes may cause unacceptable noise in some critical speeds, and the current solutions for the mitigation of this kind of vibration are, in some cases, either not effective, as torsional friction in clutch disks, or too expensive, as dual mass flywheels. For this reason, in this work, the use of centrifugal pendulum vibration absorbers on a clutch disk of a vehicle powertrain equipped with a semi-automatic gearbox is studied, aiming at reducing torsional vibration at the gearbox, leading to possible reduction of rattle noise. For this means, firstly tests are performed on the vehicle under investigation in order to obtain torsional data from its powertrain, and a linear torsional model of it is proposed next, so that the torsional dynamics of the powertrain can be represented. Then, an extensive analysis of the main types of CPVA are performed. Linear and nonlinear analyses are made in models with dimensionless parameters composed by one of two rotors and centrifugal pendulums. For the nonlinear analyses, the Method of Multiple Scales is used; a more robust and precise method than the one which has been used on the main literature in this area. Besides, the analyses are performed considering general-path pendulums and emphasis is given to the classical paths: circular, cycloid and epicycloid. Based on these analyses, two design techniques for CPVAs are proposed. Furthermore, a prototype of a clutch disk with pendulum absorbers is proposed. Then, based on project limitations, simulations are performed using the powertrain model and the nonlinear model of the CPVA. The first simulations are performed taking into consideration the project limitations, which allow a small radius for pinning the pendulum and also for a small mass of the pendulum bob, much lower than the ideal value. These simulations show that, in this case, the pendulum becomes unstable and ineffective. On the forthcoming simulations, project limitations are neglected and both pendulum design techniques are tested. With higher inertia, the pendulum absorbers are capable of providing a substantial reduction on the amplitude of vibration of the gearbox without the need for adding torsional friction to the clutch disk. However, pendulum bobs with high inertia may harm the service life of the gearbox¿s synchronizers, and further studies must be performed to evaluate this side effectDoutoradoMecanica dos Sólidos e Projeto MecanicoDoutor em Engenharia Mecânic

Multi-body dynamics in vehicle engineering

Since Euler's original gyro-dynamic analysis nearly two and a half centuries ago, the use of multi-body dynamics (MBD) has spread widely in application scope from large displacement rigid body dynamics to infinitesimal amplitude elastodynamics. In some cases, MBD has become a multi-physics multi-scale analysis, comprising contact mechanics, tribo-dynamics, terramechanics, thermodynamics, biomechanics, etc. It is an essential part of all analyses in many engineering disciplines, including vehicle engineering. This paper provides an overview of historical developments with emphasis on vehicle development and investigation of observed phenomena, including noise, vibration and harshness. The approach undertaken is comprehensive and provides a uniquely focused perspective, one which has not hitherto been reported in the literature