Conceptual Design and Optimal Torque Sharing Strategy for Hybrid Vehicles with Epicyclic Gear Trains

2012 ◽  
Vol 152-154 ◽  
pp. 759-764
Author(s):  
Nazim Mir-Nasiri
Keyword(s):  
Degrees Of Freedom ◽  
Combustion Engine ◽  
Power Sharing ◽  
Gear Train ◽  
Ic Engine ◽  
Power Sources ◽  
Epicyclic Gear ◽  
Exhaust Gas Emission ◽  
Wide Range ◽  
Sharing Strategy

The paper presents a novel approach in torque sharing between an internal combustion engine (IC engine) and two electrical motors for optimal drive of a hybrid vehicle. The concept of the system is realized by employing the three degrees of freedom (DOF) twin epicyclic gear train with specially selected gear ratios to satisfy an optimal power sharing strategy. The first stage of the train provides high torque from the IC engine and moderate torque from the motor M1. The second stage provides lower torque but higher speed from the motor M2. Such arrangement of power sources is achieved by carefully selecting of all the gear ratios in the train. The designed system is able to minimize the power usage of the IC engine and thus to minimize the exhaust gas emission, save cost of petrol as compared to normal petrol vehicle. It also provides a quite wide range of torque and speed values to drive the vehicle.

Optimal Design of IC Engine Cooling Fins by Using Genetic Algorithm

2014 ◽  
Author(s):  
Terry Yan ◽  
Jason Yobby ◽  
Ravindra Vundavilli
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithms ◽  
Optimal Design ◽  
Degrees Of Freedom ◽  
Combustion Engine ◽  
Local Heat Transfer ◽  
System Component ◽  
Cylinder Wall ◽  
Ic Engine ◽  
Engine Cooling

The analysis for optimal design of an air-cooled internal combustion engine cooling fin array by using genetic algorithms (GA) is presented in this study. Genetic Algorithms are robust, stochastic search techniques which are also used for optimizing highly complex problems. In this study, the fin array is of the traditional circular fin type, which is subject to ambient convective heat transfer. The parameters (degrees of freedom) selected for the analysis include the cylinder wall thickness-to-radius ratio, fin thickness, fin length, the number of fins, and the local heat transfer coefficient. By using a single objective GA procedure, the heat transfer through the fin arrays is set as the objective function to be optimized with each parameter varied within the physical ranges. Proper population size is selected and the mutations, cross-over and selection are conducted in the GA procedure to arrive at the optimal set of parameters after a certain number of generations. The GA proves to be an effective optimization method in the thermal system component designs when the number of independent variables is large.

scholarly journals New Intelligent Transmission Concept for Hybrid Mobile Robot Speed Control

10.5772/5784 ◽  
2005 ◽  
Vol 2 (3) ◽  
pp. 27 ◽  
Author(s):  
Nazim Mir-Nasiri ◽  
Sulaiman Hussaini
Keyword(s):  
Mobile Robot ◽  
Extreme Case ◽  
Planetary Gear ◽  
Speed Control ◽  
Torque Converter ◽  
Dc Motor ◽  
Gear Train ◽  
Ic Engine ◽  
Power Sources ◽  
Speed Controller

This paper presents a new concept of a mobile robot speed control by using two degree of freedom gear transmission. The developed intelligent speed controller utilizes a gear box which comprises of epicyclic gear train with two inputs, one coupled with the engine shaft and another with the shaft of a variable speed dc motor. The net output speed is a combination of the two input speeds and is governed by the transmission ratio of the planetary gear train. This new approach eliminates the use of a torque converter which is otherwise an indispensable part of all available automatic transmissions, thereby reducing the power loss that occurs in the box during the fluid coupling. By gradually varying the speed of the dc motor a stepless transmission has been achieved. The other advantages of the developed controller are pulling over and reversing the vehicle, implemented by intelligent mixing of the dc motor and engine speeds. This approach eliminates traditional braking system in entire vehicle design. The use of two power sources, IC engine and battery driven DC motor, utilizes the modern idea of hybrid vehicles. The new mobile robot speed controller is capable of driving the vehicle even in extreme case of IC engine failure, for example, due to gas depletion.

Theoretic Study of Efficiency of Two-DOFs of Epicyclic Gear Transmission via Virtual Power

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Chao Chen ◽  
Teck Teh Liang
Keyword(s):  
Design Optimization ◽  
Fundamental Form ◽  
Degrees Of Freedom ◽  
Gear Transmission ◽  
Gear Train ◽  
Mechanical Transmission ◽  
Virtual Power ◽  
Two Degrees Of Freedom ◽  
Analytical Expression ◽  
Epicyclic Gear

Epicyclic gear train is a fundamental form of mechanical transmission with broad applications. Efficiency study of these trains is critical to design, optimization, and operation. It is known that the efficiencies of these systems are highly related to the internal power flows. We apply the concept of virtual power to find analytical expression of the efficiency of a two degrees of freedom train, with associated applicable ranges. The results are verified by an example.

Hydrogen Storage in Quasicrystals

MRS Bulletin ◽  
1997 ◽  
Vol 22 (11) ◽  
pp. 69-72 ◽  
Author(s):  
K.F. Kelton ◽  
P.C. Gibbons
Keyword(s):  
Hydrogen Storage ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Low Cost ◽  
Atomic Diffusion ◽  
Nickel Metal ◽  
Nickel Metal Hydride ◽  
Power Sources ◽  
Transition Metal Alloys ◽  
Wide Range

Quasicrystals may have important applications as new technological materials. In particular, work in our laboratory has shown that some quasicrystals may be useful as hydrogen-storage materials.Some transition metals have a capacity to store hydrogen to a density exceeding that of liquid hydrogen. Such systems allow for basic investigations of solid-state phenomena such as phase transitions, atomic diffusion, and electronic structure. They may also be critical materials for the future energy economy. The depletion of the world's petroleum reserves and the increased environmental impact of conventional combustion-engine powered automobiles are leading to renewed interest in hydrogen. TiFe hydrides have already been used as storage tanks for stationary nonpolluting hydrogen internal-combustion engines. Nickel metal-hydride batteries are commonly used in a wide range of applications, most notably as power sources for portable electronic devices—particularly computers. The light weight and low cost of titanium-transition-metal alloys offer significant advantages for such applications. Unfortunately they tend to form stable hydrides, which prevents the ready desorption of the stored hydrogen for the intended use.Some titanium/zirconium quasicrystals have a larger capacity for reversible hydrogen storage than do competing crystalline materials. Hydrogen can be loaded from the gas phase at temperatures as low as room temperature and from an electrolytic solution. The hydrogen goes into solution in the quasicrystal structure, often avoiding completely the formation of undesirable crystalline hydride phases. The proven ability to reversibly store variable quantities of hydrogen in a quasicrystal not only points to important areas of application but also opens the door to previously inaccessible information about the structure and dynamics of this novel phase. Selected results illustrating these points appear briefly here.

Simplified modellization of gear micropitting

2002 ◽  
Vol 216 (6) ◽  
pp. 291-302 ◽  
Author(s):  
F Antoine ◽  
J-M Besson
Keyword(s):  
Film Thickness ◽  
Thermochemical Treatment ◽  
Gear Train ◽  
Surface Finishing ◽  
Case Hardening ◽  
Reference Case ◽  
Oil Film ◽  
Epicyclic Gear ◽  
Wide Range ◽  
Physical Phenomena

This document gives a simplified method of calculating gear micropitting. The method has been developed by EUROCOPTER. The objective was to provide a model that took into consideration the maximum number of parameters in order to model the different physical phenomena, particularly: an oil-film thickness calculation taking the influence of pressure into consideration a simplified modellization of roughness an estimation of the plastification effect on the roughness overpressure at the contact surface taking into account the combined effects of roughness and oil-film thickness. The elaborated model is presented in an Excel file form. The application program is called APICS (approche du pitting par calculs simplifiés). In order to validate this model, this program has been applied to: An epicyclic gear train of a helicopter. Tests on discs as part of the ASETT European program. Discs are in hardened M50NiL Duplex (surface treatment: carburized and nitrided). Different kinds of surface finishing were proposed. The reference case of discs in 16NCD13 without thermochemical treatment has been also treated. FZG gear benchtests, also as part of the ASETT program. Gears have been manufactured in hardened M50NiL Duplex, with different kinds of surface finishing proposed. The results of the calculations express quite exactly the experimental facts observed on discs and gears for a wide range of studied cases, covering different materials, different kinds of case hardening and different kinds of surface finishing.

Complete Efficiency Analysis of Epicyclic Gear Train With Two Degrees of Freedom

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Kieran Davies ◽  
Chao Chen ◽  
Bernard K. Chen
Keyword(s):  
Optimal Design ◽  
Power Flow ◽  
Degrees Of Freedom ◽  
Efficiency Analysis ◽  
Operating Conditions ◽  
Gear Train ◽  
Virtual Power ◽  
Two Degrees Of Freedom ◽  
Epicyclic Gear ◽  
Gear Trains

Epicyclic gear trains (EGTs) are important mechanical transmissions with many applications. For optimal design and operation of these gear trains, it is necessary to obtain complete efficiency maps of such transmissions. The efficiency of a two degrees of freedom (two-dof) EGT is derived based on the internal power flow and virtual power flow patterns. Expressions for the efficiencies in different operating conditions are obtained and verified by three special conditions.

scholarly journals MR- and ER-Based Semiactive Engine Mounts: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Mohammad Elahinia ◽  
Constantin Ciocanel ◽  
The M. Nguyen ◽  
Shuo Wang
Keyword(s):  
Combustion Engine ◽  
Fuel Efficiency ◽  
Power Sources ◽  
Hybrid Propulsion ◽  
Vibration Isolators ◽  
Engine Mounts ◽  
Hydraulic Hybrid ◽  
Wide Range ◽  
Multiple Power ◽  
Noise Vibration

Hybrid propulsion technologies, including hybrid electric and hydraulic hybrid, equip vehicles with nonconventional power sources (in addition to the internal combustion engine) to provide higher fuel efficiency. However, these technologies tend to lead to higher levels of noise, vibration, and harshness in the vehicles, mainly due to the switching between the multiple power sources involved. In addition, the shocks and vibrations associated with the power sources switching may occur over a wide range of frequencies. It has been proven that passive vibration isolators (e.g., elastomeric and hydraulic mounts) are unable to mitigate or totally isolate such shocks and vibrations. Active mounts, while effective, are more complex, require significant power to operate, and can lead to system instabilities. Semiactive vibration isolators have been shown to be as effective as active mounts while being less complex and requiring less power to operate. This paper presents a review of novel semiactive shock and vibration isolators developed using magnetorheological and electrorheological fluids. These fluids change their yield stress in response to an externally applied magnetic and electric field, respectively. As a result, these fluids allow one to transform a passive hydraulic vibration isolator into a semiactive device.

Understanding Conformational Entropy in Small Molecules

2020 ◽  
Author(s):  
Lucian Chan ◽  
Garrett Morris ◽  
Geoffrey Hutchison
Keyword(s):  
Small Molecules ◽  
Degrees Of Freedom ◽  
Absolute Error ◽  
Low Energy ◽  
Standard Entropy ◽  
Free Energies ◽  
Conformational Entropy ◽  
Wide Range ◽  
High Degree ◽  
Empirical Corrections

The calculation of the entropy of flexible molecules can be challenging, since the number of possible conformers grows exponentially with molecule size and many low-energy conformers may be thermally accessible. Different methods have been proposed to approximate the contribution of conformational entropy to the molecular standard entropy, including performing thermochemistry calculations with all possible stable conformations, and developing empirical corrections from experimental data. We have performed conformer sampling on over 120,000 small molecules generating some 12 million conformers, to develop models to predict conformational entropy across a wide range of molecules. Using insight into the nature of conformational disorder, our cross-validated physically-motivated statistical model can outperform common machine learning and deep learning methods, with a mean absolute error ≈4.8 J/mol•K, or under 0.4 kcal/mol at 300 K. Beyond predicting molecular entropies and free energies, the model implies a high degree of correlation between torsions in most molecules, often as- sumed to be independent. While individual dihedral rotations may have low energetic barriers, the shape and chemical functionality of most molecules necessarily correlate their torsional degrees of freedom, and hence restrict the number of low-energy conformations immensely. Our simple models capture these correlations, and advance our understanding of small molecule conformational entropy.

scholarly journals Quantum information probes of charge fractionalization in large-N gauge theories

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Brandon S. DiNunno ◽  
Niko Jokela ◽  
Juan F. Pedraza ◽  
Arttu Pönni
Keyword(s):  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Entanglement Entropy ◽  
Coarse Grained ◽  
Strongly Coupled ◽  
Information Theoretic ◽  
Large N ◽  
Wide Range ◽  
Charge Fractionalization ◽  
Electric Flux

Abstract We study in detail various information theoretic quantities with the intent of distinguishing between different charged sectors in fractionalized states of large-N gauge theories. For concreteness, we focus on a simple holographic (2 + 1)-dimensional strongly coupled electron fluid whose charged states organize themselves into fractionalized and coherent patterns at sufficiently low temperatures. However, we expect that our results are quite generic and applicable to a wide range of systems, including non-holographic. The probes we consider include the entanglement entropy, mutual information, entanglement of purification and the butterfly velocity. The latter turns out to be particularly useful, given the universal connection between momentum and charge diffusion in the vicinity of a black hole horizon. The RT surfaces used to compute the above quantities, though, are largely insensitive to the electric flux in the bulk. To address this deficiency, we propose a generalized entanglement functional that is motivated through the Iyer-Wald formalism, applied to a gravity theory coupled to a U(1) gauge field. We argue that this functional gives rise to a coarse grained measure of entanglement in the boundary theory which is obtained by tracing over (part) of the fractionalized and cohesive charge degrees of freedom. Based on the above, we construct a candidate for an entropic c-function that accounts for the existence of bulk charges. We explore some of its general properties and their significance, and discuss how it can be used to efficiently account for charged degrees of freedom across different energy scales.

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