• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.94-110
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• 1997

In the present study, a mean torque predictive model has been proposed and experimentally validated. It includes induction air mass model, fuel delivery model and mean production mode. Air induction and fuel delivery model considering dynamic behaviors of air induction and fuel delivery were proposed to predict the air-fuel ratio excursions under transient condition. Torque function model reflects thermal efficiency, volumetric efficiency, friction and effect of spark timing. In the spark timing model, knock limit and acceleration retard are included. Experiments were carried out to validate the simulation model for the step changes of throttle at constant engine speed. The results show reasonable agreements between simulation and experiment at fully warmed condition. Using this model, fueling strategies are varied with fast throttle open and it can predict air-fuel ratio excursion and IMEP.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.622-627
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• 2003

A numerical study is made of a flow in a cylinder with a rotating grooved endwall disk. The aim is to describe differences in the flow fields when there is concentrically-grooved obstacle characterized by amplitude(a) and wave number(N). The Reynolds number(Re) is varied from $10^{3}$ to $10^{4}$ and the aspect ratio(Ar) fixed to 1.0 for the most part of the simulation. For the various cases of amplitude(a) and wave number(N), numerical results are acquired. As the endwall groove roughness increases until certain limit, the interior azimuthal velocity component(v) increases drastically. But over the limit, the swirl motion chararcterized by velocity v decreases and finally it approaches much alike Ar=1.0-a case. The reason of activating swirl motion is based on increasing of torque transported by endwall disk. Torque coefficients($C_{T}$) are aquired for the various (a,N,Re) combinations and the limiting phenomena of swirl motion activation is explained.

• Transactions of the Korean hydrogen and new energy society
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• v.6 no.1
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• pp.23-34
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• 1995

In order to realize the ultra lean burn, the method of hydrogen supplement in gasoline engine has been examined and analyzed. A small quantity of hydrogen gas was supplied and mixed with gasoline fuel in the intake manifold. As the results, lean limit was extended to fuel-air equivalence ratio 0.35 which normal combustion was impossible by gasoline fuel. The NO and CO were remarkably decreased, and thermal efficiency and torque were increased. It was also found that by considering cycle variation, emission characteristics, torque and thermal efficiency, suitable operate region of hydrogen supplemented gasoline engine was equivalence ratio 0.5.

• Journal of Magnetics
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• v.13 no.4
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• pp.153-156
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• 2008

We conducted a micromagnetic modeling study to investigate the spin torque oscillator (STO) using a perpendicular polarizer. We used an additional layer of negative anisotropy constant materials (NAM) on a conventional STO. For the NAM layer, the magnetic easy plane is parallel to the in-plane easy axis of the free layer, and inhibits the development of the out-of-plane component of the magnetization in the free layer. As a result, this new type of STO provides a high frequency limit up to 50 GHz.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.85-92
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• 1994

With the wide application of fiber-reinforced composite meterial in aircraft space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structure. In this paper, the torque transmission capacities of the adhesive tubular single lap joint and double lap joint were studied. The stress and torque transmission capacity of the adhesive joints were analyzed by the finite element method and compared to the experimental results. The torque capacity of the double lap joint was increased 2.7 times over that of the single lap joint. Also, the fatigue limit of the double lap joint was increased 16 times over that of the single lap joint.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1298-1307
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• 2001

Recently, the efforts to improve fuel economy and to reduce pollutant emission have become the main subject in the development of a gasoline engine. A lean combustion engine admitted as the best alternative is relatively lower fuel consumption rate and exhaust emissions. In this study, it is focused on intensifying intake flow field as one of methods to improve the performance of the lean combustion. First, three different types of suitable swirl control valve(SC7) with high swirl and tumble ratio are selected through steady flow experiment, being installed in a spark ignition engine. The relationship between lean misfire limit and torque was investigated with injection timing and spark ignition timing. Also, the effect of intensified swirl new on the combustion Stability and exhaust emissions was experimently examined by the measuring in-cylinder pressure and combustion variation. The results show that the engine with swirl control calve is superior to other conventional engine on the lean misfire limit, specific torque, combustion variation and emission, and the appropriate injection timing and spark ignition timing exist according to the type of swirl control valve.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.938-947
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• 2003

In this paper, we derived the formula for estimating the power of the electric motors needed to operate the Decanter-type centrifuge. In the derivation of the formula the sludge-removal torque is to be supplied from the formula derived in the first paper. The intricate nature of the transmission mechanism in the planetary gear trains of the sludge-removal power and torque has been clarified in this second paper. In particular we considered two-motor system, where the main motor drives the machine while the differential-speed control motor plays the role of braking in adjusting the differential speed. Sample calculation for the specific design treated in the first paper showed that the selection criterion for the main motor depends on the lower limit of the differential speed; when the lower limit is set low, it should be selected based on the steadily operating power, while it should be selected based on the starting power when the lower limit is set high. The total power required by both the main motor and the differential-speed control motor increases as the differential speed is decreased. It is suggested that the power loss in the differential-speed control motor could be minimized by attaching an electric generator to it.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.298-301
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• 1990

This paper presents technologies to improve the control of an impact wrench. Impact wrench is a tool which is held by the electro-mechanical manipulator and used to fasten and loosen the bolts for remote maintenance of equipment in hostile environment. Vision system was developed to measure the distance and improve the positioning of the impact wrench. The vision system used two laser beams with a CCTV camera. Also, a torque adjusting method was developed to limit the fastening torque.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.363-366
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• 2009

The maximum output torque developed by the machine is dependent on the allowable current rating and maximum voltage that the inverter can supply to the machine. Therefore, to use the inverter capacity fully, it is desirable to use the control scheme considering the voltage and current limit condition, which can yield the maximum torque per ampere over the entire speed range. This controller is controlled speed and current using hybrid PI(HBPI) controller and estimation of speed using ANN. Also, this paper is proposed control of maximum torque per ampere(MTPA) of induction motor. This strategy is proposed which is simple in structure and has the honest goal of minimizing the stator current magnitude for given load torque. The performance of the proposed induction motor drive with maximum torque control using HBPI controller is verified by analysis results at dynamic operation conditions.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.778_779
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• 2009

The maximum output torque developed by the machine is dependent on the allowable current rating and maximum voltage that the inverter can supply to the machine. Therefore, to use the inverter capacity fully, it is desirable to use the control scheme considering the voltage and current limit condition, which can yield the maximum torque per ampere over the entire speed range. The paper is proposed maximum torque control of induction motor drive using adaptive learning neuro fuzzy controller and artificial neural network(ANN). The control method is applicable over the entire speed range and considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d, q axis current $_i_{ds}$, $i_{qs}$ for maximum torque operation is derived. The proposed control algorithm is applied to induction motor drive system controlled adaptive learning neuro fuzzy controller and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper is proposed the analysis results to verify the effectiveness of the adaptive learning neuro fuzzy controller and ANN controller.