• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.161-166
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• 2003

In order to improve the fatigue lift of a lower control arm in the vehicle suspension, a new shape optimization procedure is presented. In this approach, the shape control point concept is introduced to reduce the numbers of shape design variables. Also, the two-level orthogonal way is employed to evaluate the design sensitivity of fatigue life with respect to those shape design variables, because the analytical design sensitivity information is not directly supplied from the commercial CAE softwares. In this approach, only the six design variables are used to approximate the shape of lower control arm. Then, performed are only 10 fatigue life analyses including the baseline design, 8 DOE models and the final design. The final design, the best combination obtained from the sensitivity information, can maximize the fatigue lift nearly two times as that of the baseline design, while reducing the 12 percentage of weight than it.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.127-133
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• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.138-144
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• 2014

This study investigates the air resistance due to deflector configurations of commonly used largetrucksat a driving speedof 80 km/h. Of the 6 models that are considered, the drag causedby the pressure on the front part of the trailer is largest for model 1. For model 1, the lift caused by the difference between the velocities of the upper and lower streams isgreatest amongall the models. Model 6 has the least resistance against the flow stream consideringthedrags and lifts of theflow models. Anoptimal design can be obtainedby investigating thesimulation analysis ofvarious deflector configurationsfor the upper part of largetrucks; this optimum deflector configuration will help reduce the air resistanceon large trucks.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.1-8
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• 1996

The component analysis of wax for detecting temperature in automobile thermostat of the automotive engine and manufacture of it with distillation and solvent extraction were progressed. From the lift test results of prepared samples, it was found that the solvent extracted samples were in the proper range for use as an automobile thermostat of the automotive engine. And more accurate wax could be manufactured by high vacuum fractional distillation and acid treatment after solvent extraction from crude oil pitch.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.34-43
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• 2001

Analysis and control of intake charge motion such as swirl and tumble are very important to improve the performance of gasoline engines. In this paper, single frame double exposure PTV(particle tracking velocimetry) is used to investigate intake flow characteristic in a steady flow test rig of gasoline engine with 2-valve and pent-roof combustion chamber. To validate this PTV method, we confirmed reliability of this PTV method using chopper, and coaxial burner experiments. The velocity Held of intake flow is measured with the intake valve lift variation. It is shown that maximum flow velocity is increased and tumble flow become stronger than inverse tumble flow as valve lift increase.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.11-18
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• 2001

To clarify the influence of SAC shape of hole-type diesel nozzle on injection characteristics and spray patterns, the injection rate of three nozzle types(standard SAC nozzle, Needle-cut VCO nozzle and VCO nozzle) were measured by Zeuch's method and pictures of the sprays were taken by CCD camera. As the pump speed became higher, the injection characteristics of the three nozzles were different. Injection rate and perssure curves at the high pressure pipe in Needle-cut VCO nozzle were much more similar to the VCO nozzle than those of the SAC nozzle. When the needle was at pre-lift period for all speeds, the spray of the Needle-cut VCO nozzle showed almost the same shape as the SAC type nozzle. There was no differense in spray pattern at the needle full-lift periods.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.4
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• pp.35-40
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• 1987

The experimental study, using constant pressure injection system, is carried out to investigate the effect of the geometrical shape changes of the needle valve of the effective flow area, the spray angle and the Sauter's Mean Diameter according to needle valve lift for a pintle-type injection nozzle. The results are as follows: 1) With the increase of the needle valve lift, the effective flow area is increased, the spray angle is at first increased and later decreased, and the Sauter's Mean Diameter is decreased. 2) It is also shown that the spray angle is maximum at the rapidly increased region of the effective flow area.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.134-146
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• 1996

Numerical and experimental studies are performed to investigate the effect of the underbody shape of the simplified road vehicle on drag and life. Four different vehicle models with front and rear slanted variations at the lower surface are used in this study. Cases with a slanted underbody surface at front have smaller drag than those without a slanted surface. Also, cases with a slanted underbody surface at rear have smaller lift than those without a slanted surface. Pressure distributions along the model surfaces and velocity fields at the wake region are examined in detail. In general, numerical solutions are in agreement with experimental results.

• Journal of Aerospace System Engineering
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• v.14 no.4
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• pp.40-46
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• 2020

Recently, the aviation industry has sought to reduce its carbon usage in aircraft operations. Specifically, the industry is proceeding with the development of ultra-large turbofan engines and the development of hybrid electric engines to reduce the fuel consumption of aircraft. In one case, Airbus is developing as its future goal an aircraft with a short take-off distance that uses a catapult. In this study, when a b747-400 aircraft with two of the four engines removed was tested using a catapult, its fuel consumption was compared with that of the original aircraft. Fuel consumption was calculated using the mass flow consumption formula. Further, the aircraft L/D ratio caused by engine removal was interpreted using the CFD Tool, Ansys Fluent. The results showed that the lift ratio was improved by about 7% and that the fuel efficiency was improved by about 14%.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.149-156
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• 1999

In this study, aerodynmaic characteristics of the notch-back and fast-backpassenger vehicle models(1/10~1/12 acale) attached with winglets were experimentally investigated in a low speed wind tunnel. For various positions(X/L). tilted angles($\beta$) of a winglet, the aerodynamic forces on the vehicle model and rear-surface pressures were measured at various flow speeds. Also a flow of model surface was visualized by tuft method. The experimental results showed that winglets effect aerodynamic characteristics of vehicle models. A maximum of 3% reduction in lift coefficient was achieved with winglets at $\alpha$=-30$^{\circ}$. A maximum of 10% reduction in drag coefficient was achieved for a model with winglets and a rear-spoiler.