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581.
J. Son B. Reimer B. Mehler A. E. Pohlmeyer K. M. Godfrey J. Orszulak J. Long M. H. Kim Y. T. Lee J. F. Coughlin 《International Journal of Automotive Technology》2010,11(4):533-539
Driving demands significant psychomotor attention and requires even more when drivers are engaged in secondary tasks that
increase cognitive workload and divert attention. It is well established that age influences driving risk. Less is known about
how culture impacts changes in attention. We conducted parallel driving simulations in the US and Korea to measure the extent
to which age and culture influence dual-task performance. There were 135 participants divided into two groups: a younger group
aged 20∼29, and an older group aged 60∼69. Whereas some differences by culture appeared in absolute control measures, the
younger participants showed similar mean velocity and compensatory patterns associated with increased cognitive load in the
urban setting; however, the results from the older samples were less similar. 相似文献
582.
D. K. Park C. D. Jang S. B. Lee S. J. Heo H. J. Yim M. S. Kim 《International Journal of Automotive Technology》2010,11(4):489-494
This paper presents a design technique to optimize the shape of a vehicle bumper beam that satisfies both the safety requirements
for a front rigid-wall impact and the regulations protecting pedestrians from lower leg injuries caused by bumper impacts.
An intermediate response surface modeling (IRSM) technique was introduced to approximate the non-linear force-displacement
curves obtained from the front impact analysis of a vehicle bumper. The accuracy of the IRSM model was tested by comparing
its results with those of the non-linear finite element analysis. The maximum displacement error between the two models did
not exceed 3%. Using pedestrian impact analyses based on the experimental arrangement of the Plackett-Burman design, the approximate
functions describing the response values acting on the lower legs were calculated. The shape of the bumper beam was optimized
by integrating the IRSM with the force-displacement model and the approximate functions on lower leg impact. The optimization
results satisfied safety regulations on the maximum allowable displacement of the vehicle bumper, and also the regulations
protecting pedestrians from lower leg injuries caused by bumper impacts. 相似文献
583.
S. M. Park T. W. Park S. H. Lee S. W. Han S. K. Kwon 《International Journal of Automotive Technology》2010,11(1):49-56
In this study, a new concept for a power delivery system is developed. Power Shift Drive (PSD) Axle vehicle modeling and dynamic
movement analysis are performed via simulation. The dynamic vehicle model is constructed from data obtained from the derived
equation, considering the specific characteristics of each part. The model is composed of a torque converter, a gear box,
a differential, hub reduction and an engine, which is the power source of the 1st forward and reverse PSD-Axle. By unifying
the mathematical equations for each component, a mathematical model of the 1st forward gear is derived. The system dynamic
model is created using MATLAB/Simulink based on the mathematical model. Simulation is carried out using Simulink to estimate
the dynamic behavior of the PSD-Axle. In addition, the dynamo test result is used to verify the model. Finally, a successful
model is created. This study will be used to establish the basic conceptual design for the PSD-Axle multi-gear system. 相似文献
584.
S. Lee D. H. Lee M. H. Kim K. C. Lee 《International Journal of Automotive Technology》2010,11(4):525-531
The controller area network (CAN) is the dominant protocol for in-vehicle network (IVN) systems because it provides bounded transmission delay among electronic control units (ECUs) at data rates between 100 Kbps and 1 Mbps. Many automotive companies have chosen the CAN protocol for their chassis network system of intelligent vehicles. However, the increasing number of ECUs in intelligent vehicles and the need for more intelligent functions require a network system with more network capacity and real-time capability. As one approach to enhance the network capacity of a CAN system, this paper introduces a CAN system with dual communication channels. This paper also presents a traffic-balancing algorithm that predicts the traffic of each channel and allocates frames to the most appropriate channel. An experimental testbed using commercial off-the-shelf microcontrollers with two CAN controllers was used to demonstrate the feasibility of the traffic-balancing algorithm. 相似文献
585.
T. -Y. Koo B. -Y. Kim H. -J. Shin Y. -T. Son S. -W. Kim M. -W. Suh 《International Journal of Automotive Technology》2010,11(5):743-749
Driving simulators are useful tools that can be used not only to test the components of future cars, but also to evaluate
the telematics service and HMI (Human-Machine Interface). However, driving simulators that are currently available cannot
be implemented to test and evaluate a real commercial telematics service system because the GPS (Global Positioning System),
which contains basic functional support for the telematics module, does not work in the VR (virtual reality) environment.
A driving simulator, together with the GPS simulator, can be used to study the HMI to evaluate commercial CNS (Car Navigation
Systems). In this paper, Sungkyunkwan University Driving Simulator (SKUD) is developed with a GPS simulator that is able to
emulate GPS satellite signals and includes the NMEA-0183 protocol and RS232C communication standards. Furthermore, using the
SKUD, the HMI of the real commercial CNS could be investigated with driver workload assessment methods. 相似文献
586.
M. -K. Kim 《International Journal of Automotive Technology》2010,11(5):751-758
License plate location is a challenging task that is necessary for automatic vehicle identification. This paper presents a
new method for locating a license plate when its size and aspect ratio are highly variable. The proposed method begins with
an assumption that a license plate exists in a region where dense edges are located. We define an edge region as an area containing
rich edges. The edge regions are created by dilating vertical edges, and they are classified into one of four types: left
fragment type, right fragment type, whole type, and undefined type. The candidates for a license plate region are constructed
by merging edge regions. Knowing what type of edge region is being examined is useful in the merging process. Finally, we
verify whether each candidate contains a license plate or not by using the character arrangement information. The arrangement
pattern is determined by the size of connected components and by the vertical overlap or horizontal distance between two neighboring
components. Experimental results show that the proposed method gives robust results regardless of any variation in the size
and aspect ratio of license plates. 相似文献
587.
G. S. Jung Y. H. Sung B. C. Choi M. T. Lim 《International Journal of Automotive Technology》2009,10(1):1-7
Compression ignition of homogeneous charges in internal combustion (IC) engines is expected to offer high efficiency of DI
diesel engines without high levels of NOx and particulate emissions. This study is intended to find ways of extending the
rich limit of HCCI operation, one of the problems yet to be overcome. Exhaust emissions characteristics are also explored
through analyses of the combustion products. DME fuel, either mixed with air before induction or directly injected into the
combustion chamber of a rapid compression and expansion machine, is compressed to ignite under various conditions of compression
ratio, equivalence ratio, and injection timing. The characteristics of the resulting combustion and exhaust emissions are
discussed in terms of the rate of heat release computed from the measured pressure, and the concentrations of THC, CO, and
NOx are measured by FT-IR and CLD. The experimental data to date show that operation without knock is possible with mixtures
of higher equivalence ratio when DME is directly injected rather than when it is inducted in the form of a perfectly homogeneous
fuel-air mixture. Although fuel injected early in the compression stroke promotes homogeneity of the DME-air mixture in the
cylinder, it causes the mixture to ignite too early to secure good thermal efficiency and knock-free operation at high loads.
Low temperature reactions occur at about 660K regardless of the fueling methods, fuel injection timing and equivalence ratio.
The main components of hydrocarbon emissions turned out to be unburned fuel (DME), formaldehyde and methane. 相似文献
588.
S. S. Merola P. Sementa C. Tornatore B. M. Vaglieco 《International Journal of Automotive Technology》2009,10(5):545-553
A low-cost solution based on fuel injection strategies was investigated to optimize the combustion process in a boosted port
fuel injection spark ignition (PFI SI) engine. The goal was to reduce the fuel consumption and pollutant emissions while maintaining
performance. The effect of fuel injection was analyzed for the closed and open valve conditions, and the multiple injection
strategies (MIS) based on double and triple fuel injection in the open-valve condition. The tests were performed on an optical
accessible single-cylinder PFI SI engine equipped with an external boost device. The engine was operated at full load and
with a stoichiometric ratio equivalent to that of commercial gasolines. Optical techniques based on 2D-digital imaging were
used to follow the flame propagation from the flame kernel to late combustion phase. In particular, the diffusion-controlled
flames near the valves and cylinder walls, due to fuel deposition, were studied. In these conditions, the presence of soot
was measured by two-color pyrometry, and correlated with engine parameters and exhaust emissions measured by conventional
methods. The open valve fuel injection strategies demonstrated better combustion process efficiency than the closed ones.
They provided very low soot levels in the combustion chamber and engine exhaust, and a reduction in specific fuel consumption.
The multiple injection strategies proved to be the best solution in terms of performance, soot concentration, and fuel consumption. 相似文献
589.
A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator.
As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop.
In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization
process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a)
the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of
pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure
dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure
modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure
and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will
be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement
spray atomization with a high quality performance in the near future. 相似文献
590.
There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling.
The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle
control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is
active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal
tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance
is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the
linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and
an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical
maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five
individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can
cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control
action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers. 相似文献