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571.
International Journal of Automotive Technology - EGR (Exhaust Gas Recirculation) is one of the most effective techniques currently available for reducing NOx emissions from compression ignition... 相似文献
572.
The electric controller is one of the most crucial components in an electric bicycle. The overall performance of the whole system heavily depends on the properties of the controller. The authors use the robust control theory to design a new H∞ robust controller for the closed speed-current dual-loop driving and braking system. The designed controller also incorporates the driving and energy recovery braking circuit. Therefore, it has energy recovery ability, which coverts the kinetic energy wasted in braking into electric energy to recharge the battery. This prolongs the driving distance per battery charge. The simulations and experiments show that the new H∞ robust controller out-performs the traditional PID controller in many respects including stability, error, responding speed and driving distance per battery charge. 相似文献
573.
With a total length of about 22 km, Tianshan Shengli Tunnel on Urumqi-Yuli Expressway is currently the longest expressway tunnel under construction in the world. It adopts the construction scheme of "3 tunnels (2 D& B main tunnels and 1 TBM-driven middle pilot tunnel) + 4 shafts", which is characterized by great construction difficulty and high technical standard requirements. The tunnel construction is faced with technical challenges such as TBM passing through large fault fracture zones, long-distance construction ventilation in three tunnels, deep and large shaft construction and logistics organization in two-main tunnel construction assisted by middle pilot tunnel. In the parallel three-tunnel method design of Tianshan Shengli Tunnel, the TBM-driven middle pilot tunnel can not only play the role of advanced pilot tunnel, but also assist the construction of the two main tunnels and speed up the construction progress. For the middle pilot tunnel, the TBM excavation diameter is 8.4 m, and the initial support is designed as 100% force-bearing capacity in construction period, which can meet the requirements for two-way material transportation, ventilation and belt mucking in the pilot tunnel. Vault suspension scheme is adopted for the continuous belt conveyor, which can reduce the impact on the material flow organization in the cross passages. Multifunctional service vehicles (MSVs) independently developed by CCCC Group are used for the transportation of TBM materials and prefabricated inverted arch blocks, which can realize double-headed driving. TBM will pass through two large fault fracture zones F6 and F7. According to the stability of the surrounding rock at the tunnel face, the targeted treatment measures would be adopted. If necessary, the scheme of "steel segment + extruded concrete" shall be used for the initial support. In case of serious machine jamming or rock collapse, the heading expansion excavation method or bypass heading method shall be used. Tianshan Shengli Tunnel adopts phased forced ventilation option, and the ventilation mode is designed in stages with the change of tunnel construction stage. The fans and air pipes used are imported ones, and a ventilation management team is set up to strengthen ventilation management and ensure ventilation quality. Highly mechanized construction is used for the two D& B main tunnels, the application of equipment such as three-arm rock drilling jumbo and wet shotcrete machine is promoted, so as to reduce the number of workers and labor intensity, and improve work efficiency. The deep shafts of Tianshan Shengli Tunnel are constructed by short-section excavation and lining mixed operation method, and the initial support is lined by formwork pouring concrete, so as to realize safe and rapid excavation. According to the research results, the construction technology scheme for Tianshan Shengli Tunnel can meet the needs of tunnel construction. The research results can be directly used to guide the construction of Tianshan Shengli Tunnel, and provide reference for the construction of extra long highway tunnels in high-altitude areas. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
574.
B. Ozdalyan 《International Journal of Automotive Technology》2008,9(1):71-80
This paper describes the initial phase of work carried out as part of an on going study investigating the interaction between
the tyre, suspension system and an antilock braking system (ABS). The modelling, analysis simulations and integration of results
have been performed using an industry standard Multibody Systems Analysis (MBS) program. A quarter vehicle model has been
used together with an individual front suspension system represented by interconnected rigid bodies. The tyre model used can
be integrated into vehicle handling simulations but only the theory associated with the generation of longitudinal braking
forces is described here. An ABS model based on slip control has been used to formulate the braking forces described in this
paper. The simulations, which have been performed braking on wet and dry road surfaces, compare the performance of two different
tyres. 相似文献
575.
In this paper we observe that most of the independently discovered balancing methods, used in transportation planning and in other fields, are in fact special cases of a method of Bregman. Examples include the usual Kruithof or Furness method, the Evans-Kirby three dimensional balancing procedure, the Murchland multiproportional balancing procedure, the Osborne or Grad method for preconditioning matrices, the Jefferson-Scott procedure for gravity models with inequality constraints, and the method considered by Macgill for partially constrained gravity models. The convergence of all of these methods follows from Bregman's general result. 相似文献
576.
This paper presents a fault detection and diagnosis (FDD) method to enhance the reliability and safety for longitudinal control
of an autonomous all-terrain vehicle (ATV). An integrated approach using decentralized and centralized FDD is proposed to
optimize the tradeoff between sensitivity and robustness. While the decentralized approach is suitable for detecting faults
in actuators and sensors directly connected to a single processor, it is sensitive to noises and disturbances and thus may
result in false alarms. On the other hand, the centralized approach is based on information communicated between multiple
processors, and it detects and diagnoses faults through analyzing concurrent computations of multiple hardware modules. However,
its performance is still limited to isolating faults specifically in terms of components in the single hardware. To incorporate
the advantages of both FDD approaches, a two-layered structure integrating both decentralized and centralized FDD is proposed
and allows us to perform more robust fault detection as well as more detailed fault isolation. Finally, the proposed method
is validated experimentally via field tests of an ATV. 相似文献
577.
U. B. Azimov K. S. Kim D. S. Jeong Y. G. Lee 《International Journal of Automotive Technology》2009,10(3):265-276
The concept of Low Temperature Combustion (LTC) has been advancing rapidly because it may reduce emissions of NOx and soot
simultaneously. Various LTC regimes that yield specific emissions have been investigated by a great number of experiments.
To accelerate the evaluation of the spray combustion characteristics of LTC, to identify the soot formation threshold in LTC,
and to implement the LTC concept in real diesel engines, LTC is modeled and simulated. However, since the physics of LTC is
rather complex, it has been a challenge to precisely compute LTC regimes by applying the available diesel combustion models
and considering all spatial and temporal characteristics as well as local properties of LTC. In this paper, LTC regimes in
a constant-volume chamber with n-Heptane fuel were simulated using the ECFM3Z model implemented in a commercial STAR-CD code.
The simulations were performed for different ambient gas O2 concentrations, ambient gas temperatures and injection pressures. The simulation results showed very good agreement with
available experimental data, including similar trends in autoignition and flame evolution. In the selected range of ambient
temperatures and O2 concentrations, soot and NOx emissions were simultaneously reduced. 相似文献
578.
S. Tamsanya S. Chungpaibulpatana B. Limmeechokchai 《International Journal of Automotive Technology》2009,10(2):251-264
The exhaust emissions and fuel consumption rates of newly registered automobiles in Thailand are currently assessed using
the standard driving cycle of the Economic Commission of Europe (ECE). Because of the highly different driving conditions,
the assessment results may not reflect realistic amounts of emissions and fuel consumption for vehicles in Bangkok traffic,
which is well known for its congestion. The objective of this study is therefore to develop a new driving cycle for vehicles
traveling on Bangkok’s main roads during peak traffic hours. This paper first presents the development of a method for selecting
representative road routes with traffic conditions that are representative of traffic in Bangkok for conducting real-world
driving speed data collection. These real-world data are obtained by driving a car equipped with a speed-time data logger
along those selected road routes. Several driving characteristics, including various profiles of microtrips, are analyzed
from the collected speed-time data, and a number of target driving parameters are then defined for use as a set of criteria
to justify the best driving cycle. A procedure for generating driving cycles from the analyzed real-driving data is also developed,
and the method to select the cycle that is most representative of Bangkok traffic is described. Comparisons found in the study
show that the target driving parameters of the newly developed driving cycle are much closer to those obtained from the real-world
measured data than those calculated from the presently used European drive cycle. This would imply that the obtained driving
cycle will produce more realistic results of the emissions and fuel consumption assessment tests for vehicles traveling in
Bangkok. The methods developed in this study for route selection and driving cycle construction can easily be adopted by other
big cities to develop their own vehicle driving cycles. Furthermore, although the developed methods are for passenger cars,
similar approaches can be applied to develop driving cycles for other types of vehicle, such as city buses and pick-up trucks. 相似文献
579.
B. Kim Y. Kim D. M. Chun S. H. Ahn J. D. Jang 《International Journal of Automotive Technology》2009,10(1):73-77
Improving the durability of an automotive V-belt pulley, which is commonly used in an automotive powertrain to transfer power
to other parts, is discussed. Fatigue life of the original V-belt pulley is predicted based on damage analysis by finite element
analysis (FEA). Stress history of the pulley during operation was found by performing consecutive static analyses on the pulley
as the pulley rotates. Assembly load (due to the tightening of the bolts) and operation load were considered to describe the
actual load conditions in a durability test. The contact condition from the belt was calculated and applied to the surface
of the pulley. Static analyses at 36 different positions of the pulley, every ten degrees of rotation, were performed to determine
the stress history of the pulley during operation. Using stress history data calculated from FE analysis, damage over one
rotation of the pulley was calculated and fatigue life, in number of rotations to failure, was estimated. An improvement to
the durability of the pulley was investigated by modifying the design of the pulley using FE analysis results. Durability
tests for the pulleys used in the analysis were carried out to verify the analytical results. Comparison between analysis
and experimental results showed that analytical results correlated with the experimental results closely. 相似文献
580.
Parametric optimization is an important step for any mechanical system design, including the development and design of a hybrid
electric bus. To obtain an optimized parameter grouping of the EQ6110HEV hybrid electric bus for best fuel economy, an orthogonal
experiment design method is applied to the parameter optimization process of the EQ6110HEV hybrid prolusion system. This paper
proposes two orthogonal experiment methods; the basically orthogonal experiment method and the synthetically orthogonal experiment
method. By this means, the development time and the testing costs are reduced, and the impact of factors and their optimal
levels are obtained by a range analysis of the experiment results. The results show that the fuel economy of the optimized
parameter grouping is improved by 4.1 percent for the four-stage urban driving cycle in China and by 8.7 percent for the Wuhan
urban driving cycle of public buses in China, in comparison with that of the parameter grouping of the current configuration. 相似文献