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831.
There has been an increased interest recently in alliances as successors of the large consortia that used to operate in the context of the conference system. Today, having become a common means and term of co-operation in a variety of other industries, alliances are posited as the response of the supply side of liner shipping to important changes on the demand side; alliances have, thus, become predominant in the most important routes for container cargoes. In recent years, however, the list of major container traffic generators and the list of major carriers of containerized cargoes have begun to contain more common entries, generally originating from the Asian region. Asia is, however, a large continent and the entrance of Asian carriers into liner shipping has not been simultaneous; the position, strategies and co-operation strategies of Asian companies have more differences than they share common features. Nevertheless, this paper suggests that alliances are a distinct form of co-operation in liner shipping and the empirical evidence based on a survey in the region supports this hypothesis. The similarity of attitudes of the major Asian container carriers vis a vis alliances is in this way revealing in terms of the range of motivations for participating in the alliance system in a globalized transport environment. 相似文献
832.
In this paper, we consider a method to create an engine emission simulation model for cycle and customer driving of a vehicle. The emission model results from an empiric approach, also taking into account the effects of engine dynamics on emissions. We analysed transient engine emissions in driving cycles and during representative customer driving profiles and created emission meta models. The analysis showed a significantly higher correlation in emissions when simulating realistic customer driving profiles using the created verified meta models (< 1 % model error) compared to static approaches, which are commonly used for vehicle simulation. Therefore, a transient modelling approach is conducted, which shows a great increase in accuracy in customer driving operation. 相似文献
833.
V. Cossalter V. Favaron E. Giolo T. Jomaa 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(10):1474-1490
Increasing the stability of a motorcycle requires an understanding of the optimal conditions of the tyre. The inflation pressure is one of the main parameters that directly affects the tyre properties, which in turn influences motorcycle stability and safety. This paper focuses on the effect of the inflation pressure of the tested tyres on motorcycle weave stability. Experimental data are collected from tests carried out in straight running at constant speed. The data analysis is based on stochastic subspace identification methods. Simulations are performed using an advanced motorcycle multi-body code with parameters measured from the tested vehicle. Finally, the comparison between simulations and experimental tests is discussed. The research results show an agreement between experimental tests and simulations where weave stability increases with inflation pressure for the specified range of tyre pressure. 相似文献
834.
835.
This paper presents a novel approach to apply the physiological signal of the human brain to the sound quality evaluation of automotive sound. In the previous work, psychoacoustic metrics were applied to the sound quality evaluation of automotive sound. Loudness among psychoacoustic metrics is used for one of major sound metrics for the objective evaluation of the sound quality of the acceleration sound inside a car. Subjective evaluation of the sound quality of the acceleration sound shows different results depending on the two different groups of participants. One group liked powerful sound when a car is accelerated: the other group liked the refine sound. Loudness of the acceleration sound is not correlated with the subjective rating of the former group whilst it is correlated with that of the latter group. This evaluation suggests that for the people who like the powerful acceleration sound, it needs to find the sound metric for the objective evaluation of the sound quality of the acceleration sound. In this paper, a driver’s brain signal is measured using electroencephalography (EEG) when a driver hears the acceleration sound of passenger cars. The signal is analyzed to obtain the relationship between brain signals and human perception. According to these results, the alpha wave correlates to the human perception of powerful sound quality of passenger cars. This interesting relationship can be used for objective evaluation of passenger car sounds. 相似文献
836.
B. Wang J. H. Choi H. W. Song H. K. Choi S. H. Hwang 《International Journal of Automotive Technology》2014,15(5):835-841
Due to the increasing use of fossil fuel, carbon dioxide emission also increased and environmental problems have emerged as social issues. Accordingly, the research about electric vehicles as personal transportation has been actively performed. An electric scooter is not as complex as an automobile, but it takes a lot of time and costs to design and develop a new vehicle due to trial and error in selecting the specifications of core components according to consumer’s requirements. In this paper, a performance simulator for an electric scooter with an in-wheel motor at the rear wheel was developed and the simulation results were verified through experiments. For a longer travelling distance with the same energy source, the regenerative braking algorithm that converts kinetic energy into electric energy during braking was applied. The usefulness of the regenerative braking control algorithm was verified through various simulation results. 相似文献
837.
Annually, thousands of unprotected pedestrians are killed or suffer serious injuries in accidents with moving vehicles. Numerous
automobile organizations have performed research on pedestrian safety. The European Enhanced Vehicle- Safety Committee (EEVC),
Working Group 17 (WG17) proposed three component subsystem tests to evaluate the friendliness of a vehicle to pedestrians:
the legform to hood test, the upper legform to bonnet leading edge test and the headform to bonnet top test. In assessing
the pedestrian friendliness of a vehicle, the present study adopted the WG17 regulations of the three component subsystem
tests. We herein describe in detail a finite element subsystem model built to analyze the pedestrian friendliness of a vehicle
using LS-DYNA. The first objective of this study was to simulate these three component subsystem impact tests and evaluate
car front aggressiveness. The second objective was to analyze the frontal structures of a vehicle and, based on the simulation
results, identify dangerous areas and provide suggestions for vehicle front design that may decrease pedestrian injuries.
The analysis of these models and the results obtained may be used to help evaluate the pedestrian friendliness of a vehicle
and guide the future development of pedestrian-friendly vehicle technologies. 相似文献
838.
Numerical study of a light-duty diesel engine with a dual-loop EGR system under frequent engine operating conditions using the doe method 总被引:1,自引:0,他引:1
J. Park K. S. Lee S. Song K. M. Chun 《International Journal of Automotive Technology》2010,11(5):617-623
Exhaust gas recirculation (EGR) is an emission control technology that allows for a significant reduction in NOx emissions
from light- and heavy-duty diesel engines. The primary effects of EGR are a lower flame temperature and a lower oxygen concentration
of the working fluid in the combustion chamber. A high pressure loop (HPL) EGR is characterized by a fast response, especially
at lower speeds, but is only applicable if the turbine upstream pressure is sufficiently higher than the boost pressure. On
the contrary, for the low pressure loop (LPL) EGR, a positive differential pressure between the turbine outlet and the compressor
inlet is generally available. However, a LPL EGR is characterized by a slow response, especially at low and moderate speeds.
In this study, of the future types of EGR systems, the dual-loop EGR system (which has the combined features of the high-pressure
loop EGR and the low-pressure loop EGR) was developed and was optimized under five selected operating conditions using a commercial
engine simulation program (GT-POWER) and the DOE method. Finally, significant improvements in the engine exhaust emissions
and performance were obtained by controlling several major variables. 相似文献
839.
Design of active suspension and electronic stability program for rollover prevention 总被引:1,自引:0,他引:1
This paper presents a method for the design of a controller for rollover prevention using active suspension and an electronic
stability program (ESP). Active suspension is designed with linear quadratic static output feedback control methodology to
attenuate the effect of lateral acceleration on the roll angle and suspension stroke via control of the suspension stroke
and tire deflection of the vehicle. However, this approach has a drawback in the loss of maneuverability because the active
suspension for rollover prevention produces in vehicles an extreme over-steer characteristic. To overcome this drawback of
the active suspension based method, ESP is designed. Through simulations, the proposed method is shown to be effective in
preventing rollover. 相似文献
840.
S. H. Jeong C. G. Choi J. N. Oh P. J. Yoon B. S. Kim M. Kim K. H. Lee 《International Journal of Automotive Technology》2010,11(3):409-416
This paper presents a low cost design and implementation of a parallel parking assist system (PPAS) based on ultrasonic sensors.
Generally, a PPAS requires several types of sensors, such as an ultrasonic sensor, camera sensor, radar sensor and laser sensor
for parking space detection. However, our proposed PPAS only requires two ultrasonic sensors on the front and lateral sides
for parking space detection. Moreover, a steering angle sensor and wheel speed sensor installed in the vehicle are used to
obtain vehicle position information for localization in ultrasonic range data. The hardware architecture of the PPAS based
on an electronic control unit (ECU) module, sensor modules and a human machine interface (HMI) module was proposed. Moreover,
the software architecture of the PPAS is based on system initialization, scheduling, recognition and a control algorithm.
In particular, a novel sensor algorithm was proposed to minimize the vehicle corner error of the ultrasonic sensor. A prototype
of the PPAS based on the proposed architecture was constructed. The experimental results demonstrate that the implemented
prototype is robust and successfully performs parking space detection and automatic steering control. Finally, the low cost
design and implementation of the PPAS was possible due to the cheap ultrasonic sensors, simple hardware design and low computational
complexity of the proposed algorithm. 相似文献