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241.
J. W. Chung J. H. Kang N. H. Kim W. Kang B. S. Kim 《International Journal of Automotive Technology》2008,9(1):1-8
Currently, due to the severity of world-wide air pollution by substances emitted from vehicles, emission control is being
enforced more strictly, and it is expected that the regulation requirements for emission will become even more severe. A new
concept combustion technology that can reduce the Nitrogen oxides (NOx) and PM in relation to combustion is urgently required.
As a core combustion technology among new combustion technologies for the next generation engine, the homogenous charge compression
ignition (HCCI) is expanding its application range by adopting a multiple combustion mode, a catalyst, direct fuel injection
and partially premixed charge compression ignition combustion using the split injection method. This paper used a split injection
method in order to apply the partially premixed charge compression ignition combustion method without significantly altering
engine specifications of the multiple combustion mode and practicality by referring to the results of studies on the HCCI
engine. Furthermore, the effects of the ratio of the fuel injection amount on split injection are investigated. From the test
results, the adequate combination of the ratio of the fuel injection amount for the split injection method has some benefit
on exhaust and fuel economy performance in a naturally aspirated single cylinder diesel engine. 相似文献
242.
Analysis of the transient atomization characteristics of diesel spray using time-resolved PDPA data 总被引:1,自引:0,他引:1
The transient atomization characteristics of a single-hole diesel spray were investigated to clarify the time-dependent droplet
formation process of the spray through time-resolved analysis of the droplet size data acquired by using a 2-D PDPA (phase
Doppler particle analyzer). Comparisons among the three single-hole diesel nozzles on the atomization characteristics were
made to confirm the effects of the hole-diameter. The hole diameter of the single-hole diesel nozzles varied with dn=0.22, 0.32 and 0.42 mm. The time-resolved diameter, SMD (Sauter mean diameter) and AMD (arithmetic mean diameter) of droplets
in diesel spray injected into still ambient air were measured. The SMD and AMD decreased with decreasing nozzle hole diameter.
The SMD distribution along the spray centerline steeply decreased with increasing axial distance before reaching a constant
value. In the time-dependent analysis of the SMD of the whole flow field, the SMD gradually increased with time after the
initiation of injection, reached a maximum value, and then decreased. 相似文献
243.
H. -M. Kim S. -K. Park K. -S. Choi H. -M. Wang D. -H. Lee D. -K. Lee Y. -S. Cha J. -S. Lee J. Lee 《International Journal of Automotive Technology》2008,9(2):149-153
An important goal in diesel engine research is the development of a means to reduce the emissions of nitrogen oxides (NOx).
The use of a cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for
reducing nitrogen oxides. Since PM (Particulate Matter) fouling reduces the efficiency of an EGR cooler, a tradeoff exists
between the amount of NOx and PM emissions, especially at high engine loads. In the present study, we performed engine dynamometer
experiments and numerical analyses to investigate how the internal shape of an EGR cooler affects the heat exchanger efficiency.
Heat exchanger efficiencies were examined for plain and spiral EGR coolers. The temperature and pressure distributions inside
these EGR coolers were obtained in three dimensions using the numerical package program FLUENT. 相似文献
244.
J. W. Lee Y. I. Jeong M. W. Jung K. O. Cha S. I. Kwon J. C. Kim S. Park 《International Journal of Automotive Technology》2008,9(4):397-403
In recent years, particle number emissions rather than particulate mass emissions in automotive engines have become the subject
with controversial discussions. Recent results from studies of health effects imply that it is possible that particulate mass
does not properly correlate with the variety of health effects attributed to engine exhaust. The concern is now focusing on
nano-sized particles emitted from I. C. engines. In this study, particulate mass and particle number concentration emitted
from light-duty vehicles were investigated for a better understanding of the characteristics of the engine PM from different
types of fuels, such as gasoline and diesel fuel. Engine nano-particle mass and size distributions of four test vehicles were
measured by a condensation particle counter system, which is recommended by the particle measurement program in Europe (PMP),
at the end of a dilution tunnel along a NEDC test mode on a chassis dynamometer. We found that particle number concentrations
of diesel passenger vehicles with DPF system are lower than gasoline passenger vehicles, but PM mass has some similar values.
However, in diesel vehicles with DPF system, PM mass and particle number concentrations were greatly influenced by PM regeneration.
Particle emissions in light-duty vehicles emitted about 90% at the ECE15 cycle in NEDC test mode, regardless of vehicle fuel
type. Particle emissions at the early cold condition of engine were highly emitted in the test mode. 相似文献
245.
J. -Y. Zhang J. -W. Kim K. -B. Lee Y. -B. Kim 《International Journal of Automotive Technology》2008,9(6):695-702
This paper investigates an active front steering control strategy based on quantitative feedback theory (QFT). By incorporating
feedback from a yaw rate sensor into the active steering system, the control system improves the dynamic response of the vehicle.
The steering response of a vehicle generally depends upon uncertain quantities like mass, velocity, and road conditions. Thus,
QFT is used to design a controller with robust performance. A multi-degree-of-freedom nonlinear model is co-simulated here
by MATLAB Simulink and ADAMS/CAR. The performance of the control system is evaluated under various emergency maneuvers and
road conditions. The result shows that the designed robust control system has good control performance and can efficiently
improve handing qualities and stability characteristics. 相似文献
246.
Prediction of interior noise by excitation force of the powertrain based on hybrid transfer path analysis 总被引:1,自引:0,他引:1
In the early design stage of a vehicle, simulation of interior noise is useful for assessment and enhancement of the noise,
vibration and harshness (NVH) performance. Traditional transfer path analysis (TPA) technology cannot simulate interior noise
since it uses an experimental method. In order to solve this problem, hybrid TPA is employed in this paper. Hybrid TPA uses
simulated excitation force as the input force, which excites the flexible body of a car at the mount points, while traditional
TPA uses the measured force. This simulated force is obtained by numerical analysis of the finite element (FE) model of a
powertrain. Interior noise is predicted by multiplying the simulated force by the vibro-acoustic transfer function (VATF)
of the vehicle. The VATF is the acoustic response in the compartment of a car to the input force at the mount point of the
powertrain in the flexible car body. The trend of the predicted interior noise based on the hybrid TPA corresponds very well
to the measured interior noise, with some difference due to not only experimental error and simulation error, but also the
effect of the airborne path. 相似文献
247.
Alexander Olshevskiy Alexey Olshevskiy Chang-Wan Kim 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(10):1471-1491
A white-box friction draft gear model has been developed. All components of the draft gear are considered. The distinctive feature of the model, as compared to its predecessor, is the transitional characteristic, which accounts for the effect of elastic deformations of the draft gear housing on the position of the friction wedge system components under loading. The adjustment of the model parameters for improved agreement with experimental data is discussed. The new model can be used in the simulation of shunting impacts for single cars and car groups represented by detailed finite-element models. An example of the simulation is presented and compared with experimental data obtained using a shunting hump test stand. 相似文献
248.
Jaegu Kang Sanghyun Chu Jeongwoo Lee Gyujin Kim Kyoungdoug Min 《International Journal of Automotive Technology》2018,19(1):27-35
In this research, the effects of three operating parameters (Diesel injection timing, propane ratio, and exhaust gas recirculation (EGR) rates) in a diesel-propane dual fuel combustion were investigated. The characteristics of dual-fuel combustion were analyzed by engine parameters, such as emission levels (Nitrogen oxides (NOx) and particulate matter (PM)), gross indicated thermal efficiency (GIE) and gross IMEP Coefficient of Variance (CoV). Based on the results, improving operating strategies of the four main operating points were conducted for dual-fuel PCCI combustion with restrictions on the emissions and the maximum pressure rise rate. The NOx emission was restricted to below 0.21 g/kWh in terms of the indicated specific NOx (ISNOx), PM was restricted to under 0.2 FSN, and the maximum pressure rise rate (MPRR) was restricted to 10 bar/deg. Dual-fuel PCI combustion can be available with low NOx, PM emission and the maximum pressure rise rate in relatively low load condition. However, exceeding of PM and MPRR regulation was occurred in high load condition, therefore, design of optimal piston shape for early diesel injection and modification of hardware optimizing for dual-fuel combustion should be taken into consideration. 相似文献
249.
S. H. Yoo N. T. Jeong K. S. Kim S. M. Yang J. H. Lee S. H. Choi M. W. Suh 《International Journal of Automotive Technology》2016,17(4):681-687
The use of plastic in vehicle development has increased. In particular, a design trend has resulted in chromiumplated plastics being used in exterior panels. Recently, as the appearance has become more important in design, the plastic radiator grille has become larger, to where it can become the primary member when a front collision happens. The radiator grille should be designed with considerations of the geometric structure, such as delamination, and material characteristics, when plastics are plated with chromium. The enlarged grille has to pass regulations like FMVSS Part 581. Although the material property of plastic has been studied before, what seems to be lacking is study on the crashworthiness of plastic radiator grilles that are plated using chromium. In this paper, in order to evaluate the crashworthiness, tensile test and front collision analysis using finite element method are performed. Tensile test is conducted with 4 types of materials, and then material properties of chromium-plated plastics are obtained. Meanwhile radiator grille’s crashworthiness is evaluated using finite element analysis method. Analysis result is evaluated according to failure criterion. Through this study, method of the assessment of plastic radiator grille’s crashworthiness considered material properties of chromium plated plastics is proposed, and it can be predicted the delamination and the failure point of radiator grille at the design step. 相似文献
250.
This paper presents a fault-tolerant brake torque controller for four-wheel-distributed braking systems with in-wheel motors and Electro-Mechanical Brakes (EMB). Mechanical and electrical faults can degrade the performance of the EMB actuators and, thus, their effects need to be compensated in vehicle dynamics level. In this study, the faults are identified as performance degradation and expressed by the gains of each actuator. Assuming the brake force distribution and the regenerative braking ratios, the over-actuated braking system is simplified into a two-input system. A sliding mode controller is designed to track the driver’s braking and steering commands, even if there exist faults in EMBs. In addition, adaptive schemes are constructed to achieve the fault-tolerant control in braking. The proposed controller and strategies are verified in the EMB HILS (Hardware-in-loop-simulation) unit for various conditions. 相似文献