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921.
S. H. Jun T. K. Kim J. Y. Jang Y. Kidoguchi 《International Journal of Automotive Technology》2009,10(6):663-668
In an earlier study, the current authors showed that an unsteady-state lifted flame generated by an equivalence ratio conversion
system for a given fuel, was similar to a steady-state lifted flame in terms of the change characteristics from a premixed
flame to a critical flame and then to a triple flame with a diffusion flame positioned in the middle according to the concentration
difference. Therefore, this study used an OH-PLIF method to investigate the characteristics of a steady-state lifted flame
and an unsteady-state lifted flame created under conditions identical to the flames in the preceding study. PLIF (Planar laser
induced fluorescence) is practically effective for visualizing the concentration fields within a flame. The resulting OH-radical
measurements showed that an unsteady-state lifted flame created under the specific conditions used in this study showed similar
tendencies in terms of OH-radical distribution, fluorescence intensity, and liftoff height, to a steady-state lifted flame,
thereby confirming that the behavior of an unsteady-state lifted flame can be effectively predicted based on the behavior
of a steady-state lifted flame. 相似文献
922.
An in-house simulation program was developed that can be utilized to predict flow characteristics such as pressure and velocities
in any flow network system comprising multiple flow components, i.e., pipe, pump, heat exchanger, valves, etc. Although the
code is intended for applications to network flow systems in a vehicle, it is written in a generalized manner to handle any
possible network configuration of flow components. Therefore, it can easily function in various industrial applications. The
network system where the flow is assumed to be one-dimensional is mathematically formulated by applying two conservation rules,
mass and energy, to each flow component. These rules produce a set of non-linear equations. These non-linear equations are
solved iteratively by adopting the Newton-Raphson scheme. This program has been tested in many different cases to demonstrate
its validity and applicability. In this paper, two examples are introduced to show how the program can be used to find solutions
in real engineering problems. Throughout the study, it was found that the code can most efficiently be used to verify a proposed
design concept in an early design stage of the vehicle development cycle. The thermal analysis portion of the program will
be dealt with in Part II of the paper. 相似文献
923.
东风雪铁龙世嘉是一款很有个性的两厢车,而它的原型车雪铁龙C4在欧洲有着很高的人气,所以世嘉自2008年10月上市以来市场表现还算是不错。由于原型车雪铁龙C4在欧洲的碰撞试验场上表现出色,获得了五星评价,所以地它国产之后在C-NCAP试验场上的表现也寄予了厚望。 相似文献
924.
Bu-Geun Paik Seong-Rak Cho Beom-Jin Park Dongkon Lee Byung-Dueg Bae Jong-Hwui Yun 《Journal of Marine Science and Technology》2009,14(1):115-126
In this study, basic experiments regarding the wireless sensor network were conducted on a 3,000-ton-class training ship as
the first step in applying the ubiquitous technology to a real ship. Various application fields of the technology in terms
of the provision of safety and convenience on a ship were identified through these experiments. To efficiently adopt the ubiquitous
technology for ship application, it is necessary to identify the state-of-the-art ubiquitous technology and to prepare countermeasures
against the harsh environment of a ship. The characteristics of the wireless sensor network were investigated on a test bed
ashore as well as on a real ship before full-scale ship application. In particular, experimental results concerning communication
depth, data transmission ratio, and battery consumption in a sensor node are described in detail. 相似文献
925.
The inception of porpoising is theoretically predicted for planing vessels. Two different approaches are presented. First,
a linear stability analysis is applied to find the porpoising limits while the hydrodynamic coefficients, i.e. added mass
and damping coefficients, are determined by either a simplified method or a numerical method. Another approach is to seek
the porpoising limits by performing nonlinear time domain simulations. Either the simplified method or the numerical method
is used in the simulations. In the numerical method, a 2D+t theory together with a boundary element method is employed. The
trim angle limits for porpoising are determined by changing the longitudinal position of the centre of gravity (COG) of the
vessel and keeping the forward speed constant. The predicted porpoising limits are compared with Day and Haag’s (Planing boat
porpoising, Thesis, Webb Institute of Naval Architecture, 1952) experimental results. The influences of parameters such as the load coefficient, the vertical position of COG and the radius
of gyration of the ship are investigated by varying those parameters in the linear stability analysis. In the nonlinear time-domain
simulations, by trying different longitudinal position of COG, one can find the critical trim angle when the porpoising commences.
The obtained trim limits agree generally with those predicted by the linear stability analysis. Bounded oscillations for the
unstable cases near the critical trim angle can be seen in the time-domain simulations due to the nonlinear effects. 相似文献
926.
A. J. Tremlett D. J. N. Limebeer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(10):1448-1473
Variations in track temperature, surface conditions and layout have led tyre manufacturers to produce a range of rubber compounds for race events. Each compound has unique friction and durability characteristics. Efficient tyre management over a full race distance is a crucial component of a competitive race strategy. A minimum lap time optimal control calculation and a thermodynamic tyre wear model are used to establish optimal tyre warming and tyre usage strategies. Lap time sensitivities demonstrate that relatively small changes in control strategy can lead to significant reductions in the associated wear metrics. The illustrated methodology shows how vehicle setup parameters can be optimised for minimum tyre usage. 相似文献
927.
928.
J.F. Guan Hai Yang S.C. Wirasinghe 《Transportation Research Part B: Methodological》2006,40(10):885-902
Passenger transportation in most large cities relies on an efficient mass transit system, whose line configuration has direct impacts on the system operating cost, passenger travel time and line transfers. Unfortunately, the interplay between transit line configuration and passenger line assignment has been largely ignored in the literature. This paper presents a model for simultaneous optimization of transit line configuration and passenger line assignment in a general network. The model is formulated as a linear binary integer program and can be solved by the standard branch and bound method. The model is illustrated with a couple of minimum spanning tree networks and a simplified version of the general Hong Kong mass transit railway network. 相似文献
929.
A. Boukehili Y. T. Zhang Q. Zhao C. Q. Ni H. F. Su G. J. Huang 《International Journal of Automotive Technology》2012,13(6):987-998
The power management strategy in many hybrid vehicles is based on expert rules and thresholds. These rule-based strategies can result in good efficiency in term of fuel economy and emissions if their thresholds and rules are accurate. However, due to the complexity and the non-linearity of the hybrid powertrain, determining accurate thresholds and rules is neither explicit nor straightforward, and experts in most cases fail to define these thresholds and rules with enough accuracy. Based on this fact, the objective of this paper is to propose a method to improve this rule-based strategy by refining its thresholds and rules. To achieve this, we used an optimization method (dynamic programming) to calculate the optimal power management, determine the optimal control signals, and extract efficient thresholds and rules that can be used in real time. Finally, simulation results for the three strategies (optimal, simple and refined strategy) are shown and discussed. 相似文献
930.
W.X. Wu B.V. Brickle J.H. Smith R.K. Luo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,30(3):229-236
A model for the numerical simulation of vehicle/track interaction and stick-slip vibration is presented. A finite element model is developed to calculate vertical contact forces. These forces are then coupled through the contact patch into a non-linear time-domain model by which the stick-slip vibration behaviour of a wheel-rail system is analysed. The investigation suggests that stick-slip vibration may occur if a vehicle which has a maligned or an initial 'wind-up' wheeiset meets a vertical irregularity or contaminants on the track. 相似文献