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111.
This work presents an experiment on the relationships between subjective and objective evaluations of vehicle handling. Ten
cars were examined objectively in several open-loop driving dynamics manoeuvres and subjectively by test persons in typical
traffic situations. Results are extracted from a stationary test (the Slowly Increasing Steer Test), and a dynamical test
(the Frequency Response Test). The subjective measurements are obtained from drivers on a rural road course via a questionnaire,
which was developed to separately investigate the quantity level perception, the so-called “Niveau”, and the more qualitative
“Liking”. These subjective “measurements” are embedded into a two-channel definition of “Steering Comfort” as a genus for
“Steering Discomfort” and “Character”. The article concentrates on developing a statistical method for the consideration of
correlations amongst the subjective/objective data. In doing so, the variance in example subjective Niveau ratings can be
significantly explained by several objective quantities. Indicators for co-domains of validated discomfort characteristics
and hints for endeavouring character Liking ranges are detected. 相似文献
112.
C. -H. Chien J. -Y. Jang Y. -H. Chen S. -C. Wu 《International Journal of Automotive Technology》2008,9(4):437-445
People use cars so frequently that they always consider the air-conditioning, and thermal comfort of the driver and passenger
when buying a new car. Therefore accurate simulation of the thermal performance of automobile air conditioners to improve
human comfort has become increasingly important. In order to improve the thermal comfort of passengers, 3-D flow motion and
thermal behavior within vehicles must be analyzed. In this paper, a numerical simulation was used to investigate thermal behavior
in a vehicle. Because air temperature at an air vent is related to the cooling capacity of the air conditioner, the cooling
capacity was calculated using ɛ-NTU (effective number of transfer unit) theoretical equations. Using the air temperature relationship between inlet and outlet
vents as boundary conditions, a 3-D unsteady κ-ɛ turbulent model was used to give a transient analysis simulation of the temperature field and flow conditions in a vehicle’s
passenger cabin. Cooling cycle analysis and conjugate heat transfer analysis at the inside surface of the cabin’s ceiling,
floor and sides were also considered. The predicted temperature distributions in the vehicles passenger cabin were in good
agreement with those obtained experimentally. 相似文献
113.
E. Zervas 《International Journal of Automotive Technology》2008,9(6):641-647
This work studies the impact of five parameters: CO and HC engine-out emissions, space velocity, average value and profile
of exhaust temperature, on Diesel CO and HC tail-pipe emissions. The first part of this work is conducted on a reactor and
shows that both HC and CO light-off temperature increases with CO and HC input concentration. CO and HC initial concentration
influence the adsorption/desorption capacities of HC only at high temperatures. Space velocity also influences CO and HC conversion
efficiency. The second part of this work studies the impact of different combinations of HC and CO engine-out emissions on
CO and HC conversion and tail-pipe emissions in the case of New European Driving Cycle. This part proposes that a Diesel oxidation
catalyst must be mainly studied at the Urban Part of NEDC, as the CO and HC conversions are very high at the extra-urban part
of NEDC. CO and HC conversion efficiencies are also dependent on exhaust temperature and catalytic volume. In the case of
two different profiles of exhaust temperature with the same average temperature, CO and HC conversion efficiency is lower
in the case of the smoother profile. 相似文献
114.
H. -Z. Li L. Li J. Song L. -Y. Yu 《International Journal of Automotive Technology》2011,12(5):679-686
A new comprehensive driver model is presented for critical maneuvering conditions with more accurate dynamic control performance.
In order to achieve a safe maneuvering mode, a new path planning scheme to maintain stability of the vehicle was designed.
A new steering strategy, considering the errors of vehicle position and yaw angle between the real track and the planned path,
was established to obtain the steering angle. Therefore, the vehicle can be adjusted to accurately follow the desired path
with the driver model, and the stability of the vehicle and the smoothness of the steering angle input were comprehensively
considered. Simulation results were used to validate the control performance in comparison with the optimal preview driver
model proposed by Macadam. 相似文献
115.
Identifying the components of a vehicle’s interior noise is important in many phases of the noise, vibration, and harshness
(NVH) development process. Many test methods that have been widely used in the automobile industry to separate noise sources
are based on system identification methods in the frequency domain. However, none of the frequency response function-based
methods can directly estimate the wind noise component. In this article, an analytical model for the interior noise level
based on a simple power law was developed. It was assumed that the mean squared acoustic pressure for the interior noise could
be obtained by summing up those of the wind noise, road noise, and background noise. The wind noise and road noise were further
assumed to depend only on wind speed and the vehicle’s driving speed, respectively, and to follow a simple power law. The
resulting analytical model includes five parameters that can be optimized for the vehicle and the road. The validity of the
model was verified by using data obtained from cruise tests performed on a proving ground for cruise speeds ranging from 40
km/h to 130 km/h. The model is applied to the overall and 1/3-octave bands of interior noise and is shown to describe the
data trends fairly well. For the test vehicle used in the present work, the overall mean squared pressures for the wind and
road noise components are shown to be proportional to the wind speed to the 5.8 power and to the driving speed to the 3.4
power, respectively. 相似文献
116.
X. D. Wu S. G. Zuo L. Lei X. W. Yang Y. Li 《International Journal of Automotive Technology》2011,12(5):671-677
The purpose of this study was to effectively identify parameters for a LuGre friction model based on experimental measures.
In earlier work related to this study (Yang et al., 2009), which was based on the characters of polygonal wear (Sueoka and Ryu, 1997), we showed a frictional vibration model
for a mass on a moving belt. This model reflected lateral vibrations caused by velocity and toe-in angle. An important aspect
of the present study is the improved friction model. A previous friction model, which divided the process into four parts,
expressed the sable excited vibration well but failed to reflect the hysteresis loop change when vehicles accelerated or decelerated
continuously. A LuGre friction model can solve this problem, but several model parameters must be obtained experimentally.
We measured contact width and length of tires as vertical pressure changed; this provided a theoretical basis for apparent
stiffness of a unit of tire tread. Based on tire data from Bakker E’s article in a SAE paper from 1987, we identified the
Stribeck exponent and Stribeck velocity in LuGre. Then, the results were implemented in a vibration system that verified the
rationality of the data. 相似文献
117.
Carlos Jerome Lawrence A. Howard Ezgi Uzel Jameela R. Androulidakis 《WMU Journal of Maritime Affairs》2017,16(1):89-98
Protection against on-ship infectious disease—whether due to mishap or to harmful purpose—faces special situational problems. Sometimes, when infection levels on board have reached threshold levels, emergency actions are required. Often, the most thorough strategies for responding to threat are not feasible. A rapid first-stage test (RFT) is a fast, minimally invasive procedure used to rule out from possible infection a large percentage of an infection-threatened group. Prevention and control of on-ship infection need to combine various interconnected tactics. When timely criterion tests are not possible, the medical team must adopt fast alternative measures. The methods used to summarize protection against on-ship infectious agents included a scientific literature review and a web search. The fields of the review were maritime, health, and technology sources. Special attention was paid to material dealing with risks and threats of on-ship penetration by infectious agents, on-ship infection prevalence thresholds, and rapid diagnostic screens. The Bayes rule and the law of large numbers were applied to the analysis, for large on-ship populations, of RFT indications of crossing of an infection prevalence threshold. The increasing risk of serious on-ship infection—either accidental or purposeful—calls for a multi-layered protection approach. RFTs are a key part of the outer layer of such a defense. Well-designed and well-administered RFTs provide several advantages for defense against on-ship infection: low-cost, non-invasive, fast, and focuses on a drastically smaller number of infection possibilities. 相似文献
118.
119.
In the present work, different ventilated disc brake rotor configurations were analysed to enhance the heat transfer rate and obtain the uniform temperature distribution in the rotor. CFD code used in this work was validated at using experimental results obtained by conducting experiments on a test rig. The experimental analysis was performed to calculate the mass flow rate and heat dissipation through the rotor. Further, different types of rotor configurations viz. straight radial vane (SRV), tapered radial vane (TRV), alternate long and short vane (ALSV), variable diameter circular pillars (VDCP) were considered for the analysis. A rotor segment of 20° was considered for the numerical analysis due to its rotational symmetry. CFD results were in good agreement with the experiments. The maximum deviation of the numerical results were about 12 % from the experimental results. It is found from the analysis that among the different types of rotor configurations; variable diameter circular pillars (VDCP) rotor gives better rate of heat dissipation with more uniform temperature distribution in the flow passages. Hence for modern high speed vehicles VDCP rotor may be more appropriate. 相似文献
120.
This paper proposes a non-linear dynamics model for articulated vehicles. This model is able to capture common low-speed behaviours of any articulated vehicles off-highway, such as operating for a corner or roundabout on a cambered or slippery surface. It can be used to assess the low-speed manoeuvrability of articulated vehicles under such manoeuvres and conditions. The vehicle model was validated by comparing its path tracking performance to that of the field tests. 相似文献