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991.
We investigated the effects of the fuel injection timing — both for early and late injection — in conjunction with the throttle
opening ratio on the fuel-air mixing characteristics, engine power, combustion stability and emission characteristics of a
DI CNG spark engine and control system that had been modified and designed according to the author’s original idea. We verified
that the combustion characteristics were affected by the fuel injection timing and that the engine conditions were affected
by the throttle opening ratios and the rpm. The combustion characteristics were greatly improved for a complete open throttle
ratio with an early injection timing and for a partial throttle ratio with a late injection timing. The combustion duration
was governed by the duration of flame propagation in late injection timing scenarios and by the duration of early flame development
in cases of early injection timing. As the result, the combustion duration is shortened, the lean limit is improved, the air-fuel
mixing conditions are controlled, and the emissions are reduced through control of the fuel injection timing and vary according
to ratio of the throttle opening. 相似文献
992.
Compensation factor method for modeling springback of auto parts constructed with high-strength steel 总被引:1,自引:0,他引:1
X. -K. Zhang G. J. Zheng J. -N. Hu C. G. Li P. Hu 《International Journal of Automotive Technology》2010,11(5):721-727
To more accurately manufacture an auto-body workpiece, a predictive compensation factor method was used to predict the workpiece’s
springback, and the factors influencing springback are introduced. Based on this method, a numerical simulation was produced
to simulate the springback compensation after distortion of the workpiece. After analyzing the simulation results, a compensation
method was introduced to reduce the springback influence on an actual workpiece. Here, we used a fortified B-pillar, which
is a kind of longitudinal stand-frame workpiece, made with a high-strength steel material (TRIP700). The simulation results
indicated that the proposed method is feasible and can be efficiently used for predicting the distortion of springback compensation
of an auto-body workpiece. 相似文献
993.
The overall driving environment consists of the Traffic environment, vehicle and driver states (TVD). advanced driver assistance
Systems (ADAS) must consider not only information on each of the TVD states but also their context. Recent research has focused
on making more efficient and effective assistance systems by fusing all the information from the TVD states. Based on this
research trend, this paper focuses on decision-level fusion to estimate the level of danger of a warning by using visual information
of the traffic environment and the driver state. The driver state consists of the gazing region and the facial feature points
that are obtained using the active appearance model (AAM). The traffic environment state consists of time to collision (TTC),
time to lane Crossing (TLC), and lane color information, which are obtained from the environment in front of the vehicle,
i.e., position of lanes and other vehicles. Warnings against lane-off, collision, and driver inattention are generated by
fusing this vision-based information from inside and outside the vehicle. The experimental results prove that our vision-based
interactive driver assistance system reduces most useless warnings. 相似文献
994.
A. Badea A. Furones F. J. Páez C. González 《International Journal of Automotive Technology》2010,11(5):711-720
Pedestrians are the most vulnerable users of public roads and represent one of the largest groups of road casualties; their
death rate around the world due to vehicle-pedestrian collisions is high and tending to rise. In Spain, as in other countries
of the European Union, steps have been taken to reduce the number and consequences of such accidents, with encouraging results
in recent years. A key to countering this concern is the accident research activity that has obtained remarkable achievements
in different fields, especially when multidisciplinary approaches are taken. This paper describes the development of a multivariate
model that is able to detect the most influential parameters on the consequences of vehicle-pedestrian collision and to quantify
their impact on pedestrian fatality risk. First, an accident database containing detailed information and parameters of vehicle-pedestrian
collisions in Madrid has been developed. The accidents were investigated on the spot by INSIA accident investigation teams
and analyzed using advanced reconstruction techniques. The model was then developed with two components: (1) a classification
tree that characterizes and selects the explanatory variables, identifying their interactions, and (2) a binary logistic regression
to quantify the influence of each variable and interaction resulting from the classification tree. The whole model represents
an important tool for identifying, quantifying and predicting the potential impact of measures aimed at reducing injuries
in vehicle-pedestrian collisions. 相似文献
995.
This work presents the modeling and simulation of a novel free piston linear alternator. The modeling consists of two parts,
a thermodynamic model and dynamic model, and these are combined and solved by matlab/simulink. The effects of various intake
pressures, moving masses, ignition positions, and resistance loads are studied. The simulation results show that the free
piston motion is different from that of the traditional internal combustion engine (ICE). The free piston accelerates and
decelerates more quickly at the end of the stroke and additionally, the top dead center is free and changes accordingly with
the studied parameters. Thus, a high compression ratio can be easily achieved. 相似文献
996.
Electro-hydraulic braking system for autonomous vehicles 总被引:4,自引:0,他引:4
V. Milanés C. González J. E. Naranjo E. Onieva T. De Pedro 《International Journal of Automotive Technology》2010,11(1):89-95
Reducing the number of traffic accidents is a declared target of most governments. Since dependence on driver reaction is the main cause of road accidents, it would be advisable to replace the human factor in some driving-related tasks with automated solutions. To automate a vehicle, it is necessary to control the actuators of a car, i.e., the steering wheel, accelerator, and brake. This paper presents the design and implementation of an electro-hydraulic braking system consisting of a pump and various valves, allowing the control computer to stop the car. It is assembled in conjunction with the original circuit for the sake of robustness and to permit the two systems to halt the car independently. This system was developed for installation in a commercial Citroën C3 Pluriel of the AUTOPIA program. Various tests were carried out to verify its correct operation, and an experiment showing the integration of the system into the longitudinal control of the car is described. 相似文献
997.
B. Suh A. Frank Y. J. Chung E. Y. Lee Y. H. Chang S. B. Han 《International Journal of Automotive Technology》2010,11(4):555-563
This research is the first to develop a design for a powertain system of a plug-in parallel diesel hybrid electric bus equipped
with a continuously variable transmission (CVT) and presents a new design paradigm of the plug-in hybrid electric bus (HEB).
The criteria and method for selecting and sizing powertrain components equipped in the plug-in HEB are presented. The plug-in
HEB is designed to overcome the vulnerable limitations of driving range and performance of a purely electric vehicle (EV)
and to improve fuel economy and exhaust emissions of conventional bus and conventional HEBs. The control strategy of the complicated
connected propulsion system in the plug-in parallel HEB is one of the most significant factors in achieving higher fuel economy
and lower exhaust emissions of the HEV. In this research, a new optimal control strategy concept is proposed against existing
rule-based control strategies. The optimal powertrain control strategy is obtained through two steps of optimizations: tradeoff
optimization for emission control and energy flow optimization based on the instantaneous optimization technique. The proposed
powertrain control strategy has the flexibility to adapt to battery SOC, exhaust emission amount, classified driving pattern,
driving condition, and engine temperature. The objective of the optimal control strategy is to optimize the fuel consumption,
electricity use, and exhaust emissions proper to the performance targets. The proposed control strategy was simulated to prove
its validity by using analysis simulation tool ADVISOR (advanced vehicle simulator). 相似文献
998.
As driver assistant systems (DAS) and active safety vehicles (ASV) with various functions become popular, it is not uncommon
for multiple systems to be installed on a vehicle. If each function uses its own sensors and processing unit, it will make
installation difficult and raise the cost of the vehicle. As a countermeasure, research integrating multiple functions into
a single system has been pursued and is expected to make installation easier, decrease power consumption, and reduce vehicle
pricing. This paper proposes a novel side/rear safety system using only one scanning laser radar, which is installed in the
rear corner of the driver’s side. Our proposed system, ISRSS (integrated side/rear safety system), integrates and implements
four system functions: BSD (blind spot detection), RCWS (rear collision warning system), semi-automatic perpendicular parking,
and semi-automatic parallel parking. BSD and RCWS, which operate while the vehicle is running, share a common signal processing
result. The target position designation for perpendicular parking and parallel parking situations is based on the same signal
processing. Furthermore, as system functions during running and those during automatic parking operate in exclusive situations,
they can share common sensors and processing units efficiently. BSD and RCWS system functions were proved with 13025 and 2319
frames, respectively. The target position designation for perpendicular and parallel parking situations was evaluated with
112 and 52 situations and shows a success rate of 98.2% and 92.3%, respectively. 相似文献
999.
J. M. Lee N. W. Sung G. B. Cho K. O. Oh 《International Journal of Automotive Technology》2010,11(3):307-316
An analytical study of the performance of a radial-type, metal foam diesel particulate filter is reported. A mathematical
model for the filtration and regeneration of soot in a metal foam filter was developed. Nickel foam was selected for the filter
medium due to its large specific area, high porosity, and high thermal resistance. For various metal foams, the filtration
efficiency and the pressure drop through the filter were calculated, as was the deposition of soot. The results from the analytical
model were compared with experimental data. In comparison with a conventional wall flow filter, the metal foam diesel particulate
filter (DPF) is effective in utilizing the volume of material, due to the porous structures. As the size of the metal foam
pores in the DPF increases from 580 μm to 800 μm, the filtration efficiency decreases from 90% to 50%, and the pressure drop
decreases from 380 mbar to 20 mbar. The metal foam DPF with a large pore size is effective in utilizing the volume of material
with a small pressure drop. The regeneration is completed within four minutes by the flow of hot exhaust gases under full
load conditions. 相似文献
1000.
Buses are an integral part of the national transportation system of each country. A rollover event is one of the most important
hazards that concerns the safety of the passengers and the crew in a bus. In the past, it was observed after the accident
that the deforming superstructure seriously threatens the lives of the passengers. Thus, the stiffness of the bus frame is
the first thing that needs to be considered. The unfortunate side of strengthening the bus superstructure is that it usually
causes the bus weight to increase. This paper presents an efficient and robust analysis method with which to design the bus
superstructure for a reduction in occupant injuries from rollover accidents while the weight of the strengthened bus is maintained
at the same level. First, the absorbed energy of the bus frame and its components during a rollover were investigated by using
a LS-DYNA numerical study. The highest energy absorption region, which is the side section of the bus frame, was found and
focused on for the investigation of a means to re-distribute the energy-absorption ability of the side frame component. Then
the thickness parameters that were obtained from the re-distribution of the energy-absorption ability were used in the analysis
to optimize the design. Finally, a prototype of the bus with a reasonable thickness for the window pillars and the side wall
bars, which was based on the optimized parameters, was verified to ensure it satisfied ECE R66. In this paper, an effective
usage of materials and an efficient and robust analysis method were presented to design the bus superstructure. Although the
optimization process for increasing the stiffness is simple, this study improves the upper displacement by 39.9% and the lower
displacement by 49.3% (versus the bus survivor space) while maintaining the bus weight at the existing level. 相似文献