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141.
142.
143.
Low viscosity engine oil can improve a vehicle’s fuel economy by decreasing the friction between the engine components. Frictional
torque varies with the velocity change due to different viscosity characteristics of SAE grade 5W-20, 5W-30 and 5W-40 engine
oils. The viscosity for each of these grades was measured to outline the effect low viscosity engine oils have on engine friction,
which may lead to improved fuel economy. Engine oil seal frictional torque increases with the shaft rotational speed for all
three engine oil grades. A decrease in engine oil seal frictional torque was confirmed when low viscosity engine oil was used.
Also, the leak-free performance of the engine oil with the seal satisfied the life limit durability test criteria. Thus, low
viscosity engine oil may be used to improve fuel economy by decreasing the frictional loss of the engine oil seal while having
no negative impact on performance due to leak-free functioning. 相似文献
144.
Yean-Tzong Yang Graduate Research Assistant Benson H. Tongue Associate Professor 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1994,23(1):279-292
This paper presents current research regarding intra-platoon collision dynamics for rapid decelerations. Measures of ride quality and impact severity are introduced to allow comparisons between different collision scenarios. In this study, the disturbance input to the platoon is assumed to be a rapid braking of the lead vehicle. Several deceleration rates are used to assess the overall platoon behavior and the effect of the intra-platoon collisions on the platoon passengers. The role of the desired headway spacing on preventing the occurrence of intra-platoon collisions and improving rider comfort is discussed. 相似文献
145.
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
146.
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
147.
为适应区间铁路客运的需要,瑞士Stadler铁路成套设备公司开发了创新的轻型快速区间运输动车组FLIRT(Flinker Leichter Innovativer Regional Triebzug).该动车组以用于贯穿瑞士南北铁路连接线的瑞士中部州府而闻名.该城市必须重新评价其近郊铁路客运的设计,寻求远期的解决办法.就今天公交运输的财政形势来说,必须寻求一种费用最佳的解决办法.为此放弃了广泛新建铁路基础设施的办法,而主要是充分利用现有基础设施.对此决定将FLIRT动车组用于客、货运繁忙的南北铁路连接线.文章介绍该城市铁路动车组的设计. 相似文献
148.
H. Minamoto S. Takezono 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,34(4):229-248
This paper deals with two-dimensional motion analysis of vehicles damaged due to collision. Various parts of vehicles are damaged due to collision in general. The effects of the damage in vehicle body and wheels on the vehicle motions are investigated. The center of gravity of the vehicle and the polar moment of inertia are changed by the deformation of vehicle body. Furthermore, the geometrical relations of wheels like wheelbase, treads and steering angles may be changed by damage of the wheels. Thus the vehicle loses symmetry with respect to the vehicle axis. The four-wheel vehicle model is extended to take into account the vehicle damage due to collision. The motions of damaged vehicles are compared with those of undamaged vehicles. It is found that vehicle damages have a significant influence on vehicle motion after impact. 相似文献
149.
150.
Structural pipe-in-pipe cross sections have significant potential for application in offshore oil and gas production systems
because they combine thermal insulation performance with structural strength and self weight in an integrated way. Such cross
sections comprise inner and outer thin-walled pipes with the annulus between them fully filled by a selectable filler material
to impart an appropriate combination of properties. Structural pipe-in-pipe cross sections can exhibit several different collapse
mechanisms, and the basis of the preferential occurrence of one over the others is of interest. This article presents an exact
analysis for predicting the elastic buckling behaviours of a structural pipe-in-pipe cross section when subjected to external
hydrostatic pressure. Simplified approximations are also investigated for elastic buckling pressure and mode when the outer
pipe and its contact with the filler material is considered as a pipe on an elastic foundation. Results are presented to show
the variation of elastic buckling pressure with the relative elastic modulus of the filler and pipe materials, the filler
thickness, and the thicknesses of the inner and outer pipes. Case studies based on realistic application scenarios are used
to show that the simplified approximations are sufficiently accurate for practical structural design purposes. 相似文献