Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 4 Articles
Fuel cells and high energy density batteries have limited overrated capacity and slow power response. Ultracapacitors and flywheels\r\nare proposed to overcome these limitations and to facilitate regenerative braking in hybrid and electric vehicles. The simulations\r\npresented in this paper show that a Secondary Energy StorageUnit (SESU) enhances the performance of the drivelines as previously\r\nsuggested and provides additional improvements. A combined design of the primary energy source and the SESU reduces the total\r\nweight and volume and increases the battery lifetime. A full-electric driveline is simulated using a standard EPA FTP-75 drive\r\ncycle. Then the same vehicle is simulated with as SESU and the results are compared.The same is done for a hybrid driveline. Two\r\ndrivelines are used as references and then enhanced with an SESU; four simulations are presented in total. Simulation results show\r\nthat an energy storage device with very low energy and high power allows better battery selection and energy management....
Flux-switching motors (FSM) are competitive candidates for in-wheel traction systems. However, the analysis of FSMs presents\r\ndifficulty due to their complex structure and heavy magnetic saturation. This paper presents a methodology to rapidly construct,\r\nadapt, and solve a variable magnetic equivalent circuit of 12-stator-slot 10-rotor-tooth (12/10) FSMs. Following this methodology,\r\na global MEC model is constructed and used to investigate correlations between the radial dimensions and the open-circuit phase\r\nflux linkage of the 12/10 FSM. The constructed MEC model is validated with finite element analysis and thus proved to be able to\r\nassist designers with the preliminary design of flux-switching motors for different in-wheel traction systems....
Occupants of automobiles experience discomfort after long drives, irrespective of how well designed a seat might be. Previous\r\nstudies of discomfort during driving have focused either on the seat shape andmaterials (ââ?¬Å?staticââ?¬Â properties), long-termdiscomfort\r\n(ââ?¬Å?fatigueââ?¬Â properties), or dynamics (ââ?¬Å?vibrationââ?¬Â properties). These factors have previously not been considered together. This paper\r\nreports three studies with objectives to define and test a model for describing long-term discomfort from vibration. Study 1 was\r\nan independent measures laboratory trial using an automobile seat, which lasted 80 minutes; Study 2 was a repeated measures\r\nlaboratory trial using a rail passenger seat, which lasted 60 minutes; Study 3 was a repeated measures field trial in a people\r\ncarrier automobile, which involved 70 minutes of travelling. The findings showed that discomfort accrues with time but that more\r\ndiscomfort is experienced when subjects are also exposed to whole-body vibration. Exposure to whole-body vibration accelerates\r\ndevelopment of discomfort. The relationship between the reported discomfort, the vibration magnitude, and the exposure time\r\ncan be described using a multifactorial linear model. It is concluded that ignoring parts of the multi-factorial model (i.e., static,\r\ndynamic, or temporal factors) will compromise understanding of discomfort in context....
Optimization of gear ratio with the objectives of fuel consumption reduction and vehicle longitudinal performance improvement\r\nhas been the subject of many studies for years. Finding a strategy for changing gears with specific control objectives, especially in\r\nthe design of vehicles equipped with Continuously Variable Transition system (CVT), which has advantage of arbitrary selection\r\nof gear ratio, has been the aim of some recent researches. Optimal control theory has rarely been used in the previous control\r\napproaches applied to such systems due to the limitations in the use of fast computational systems. The aim of this study is to\r\ndesign the aforementioned gear ratio change strategy and related control rules on the basis of optimal control. A driver model is\r\nalso designed for the simulation of driving cycle usingMATLAB Simulink Toolbar. Results of implementing optimal control rules\r\nin vehicle longitudinal movement simulation with the aim of fuel consumption reduction are finally represented. The presented\r\nmethod has the remarkable advantage of considerable fuel consumption reduction in comparison to other proposed approaches\r\nfor gear ratio change strategies....
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