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H. G. Zhang E. H. Wang B. Y. Fan M. G. Ouyang S. Z. Xia 《International Journal of Automotive Technology》2011,12(2):173-182
Variable Nozzle Turbocharger (VNT) was invented to solve the problem of matching an ordinary turbocharger with an engine.
VNT can harness exhaust energy more efficiently, enhance intake airflow response and reduce engine emissions, especially during
transient operating conditions. The difficulty of VNT control lies in how to regulate the position of the nozzle at different
engine working conditions. The control strategy designed in this study is a combination of a closed-loop feedback controller
and an open-loop feed-forward controller. The gain-scheduled proportional-integral-derivative (PID) controller was implemented
as the feedback controller to overcome the nonlinear characteristic. As it is difficult to tune the parameters of the gain-scheduled
PID controller on an engine test bench, system identification was used to identify the plant model properties at different
working points for a WP10 diesel engine on the test bench. The PID controller parameters were calculated based on the identified
first-order-plus-dead-time (FOPDT) plant model. The joint simulation of the controller and the plant model was performed in
Matlab/Simulink. The time-domain and frequency-domain performances of the entire system were evaluated. The designed VNT control
system was verified with engine tests. The results indicated that the real boosting pressure traced the target boosting pressure
well at different working conditions. 相似文献
696.
T. Y. Shin S. Y. Kim J. Y. Choi K. S. Yoon M. H. Lee 《International Journal of Automotive Technology》2011,12(1):103-110
This paper presents a modified lateral control method for an autonomous vehicle with both look-ahead and look-down sensing
systems. To cope with sensor noise and modeling uncertainty in the lateral control of the vehicle, a modified LMI-based H
lateral controller was proposed, which uses the look-ahead information of the lateral offset error measured at the front of
vehicle and the look-down information of the vehicle yaw angle error between the reference lane and the centerline of the
vehicle. To verify the safety and the performance of the lateral control, a scaled-down vehicle was developed, and the positioning
of the vehicle was estimated with USAT. The proposed controller, which uses both look-ahead and look-down information, was
tested for lane changing and reference lane tracking with both simulation and experiment. The simulation and experimental
results show that the proposed controller has better tracking and handling performance compared with a controller that uses
only the look-ahead information of the target heading angle error. 相似文献
697.
K. Jang I. Park J. Han K. Lee M. Sunwoo 《International Journal of Automotive Technology》2011,12(4):589-597
Because the FlexRay protocol has more than 70 configuration parameters and these parameters correlate with each other, designing
a FlexRay network is a complex and difficult task. In this study, we propose a design framework that optimizes the two main
FlexRay network parameters that are highly relevant to the application algorithm. The design process is composed of two steps
for optimizing parameters. In the first step, the static slot length is optimized using a frame-packing algorithm. This algorithm
binds network signals into static frames based on their periods and signal groups. In the second step, the communication cycle
length is optimally designed with frame-scheduling algorithm and worst-case reponse time analysis. Based on the frame-scheduling
algorithm, the response times are analyzed. The proposed design framework was applied to a unified chassis control system
as a case study, and the analytical results were verified. 相似文献
698.
699.
T. -H. Chang M. -C. Wang S. -M. Yu 《International Journal of Automotive Technology》2011,12(6):933-942
This study develops a longitudinal control model for automatic car-following with one switch and two controllers. The switch
is operated using fuzzy logic to activate acceleration or trigger braking. The two controllers activate the acceleration pedal
and the brake system and use reference adaptive control theory. A simulation is utilized to evaluate the acceptability of
the proposed model and to compare the traffic characteristics between machine driving (by the proposed model) and human driving
(as represented by the GM-V model). The simulation results indicate that this model is acceptable and is both safe and efficient
for use in traffic. However, the automatic car-following system is more aggressive than humans are, which may be the primary
challenge in implementation. 相似文献
700.
D. H. Kim J. M. Lee E. H. Park J. H. Song S. I. Park 《International Journal of Automotive Technology》2011,12(3):409-416
A comprehensive study evaluating the performance of biobutanol-blended gasoline in passenger cars was conducted because biobutanol
is considered a better biofuel than bioethanol as it has no water solubility and it has a higher caloric value, giving it
a higher energy value. Several kinds of samples—suboctane gasoline, 8 volume percentage and 16 volume percentage biobutanol—blended
gasoline, and a 10 volume percentage MTBE-blended market sample (as the oxygencontaining gasoline)-were tested to evaluate
the engine performance in terms of the detergency of the intake valves and combustion chambers, power, emissions, and fuel
efficiency. Additionally, the toxicity of the emissions from these biobutanolblended samples was tested in order to assess
the viability of biobutanol as one of the competitive potential substitutes for MTBE as an oxygenator in the near future.
The results show that biobutanol-blended gasoline samples had relatively better detergency, relatively higher power, and similar
levels of emissions compared with those of MTBE-blended gasoline. Formaldehyde was emitted from all of the samples at almost
the same levels and within the error range, whereas biobutanolblended gasoline samples emitted approximately three times the
amount of acetaldehyde than did the suboctane gasoline. This study shows that biobutanol is one of the best alternative bioalcohol
fuels for use in the near future. 相似文献