• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.110-118
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• 2015

In this study, it is designed and used the test engine bed which is installed with turbocharger, and in addition to equipped using by oxygen adder. It has been controlled the oxygen volumetric fraction of intake air chrge, and supercharged flow rate into the cylinder of SI 4-stroke engine, and then, has been analyzed engine performance, combustion characteristics, and exhaust emission as analysis parameters. The tested parameters were the oxygen fraction and the variation of engine speed and air-fuel ratio.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.648-656
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• 2015

Active SAR satellite's main maneuver is roll axis maneuver to change SAR antenna direction. In addition, yaw steering is required to minimize the doppler centroid variation. Thus, it is resonable to assign the torque/momentum capacity mostly to roll axis and then yaw axis. In this case, the pitch axis shows low agility performance. However, due to orbit maintenance, large angle maneuver about pitch axis is sometimes required. In this paper, we study the pitch axis maneuver time reduction through sequential rotation about roll and yaw axis. Since these two axes have high agility performance than pitch axis, maneuver time reduction is possible when large angle rotation about pitch axis is required.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1113-1114
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• 2011

This paper is proposed design of high performance controller of SynRM drive using FNN and NNC. Also, This paper is proposed of designing fuzzy neural network controller(FNNC) which adopts the fuzzy logic to the artificial neural network(ANN). FNNC combines the capability of fuzzy reasoning in handling uncertain information and the capability of neural network in learning from processes. This controller is controlled speed using FNNC and model reference adaptive fuzzy control(MFC), and estimation of speed using ANN. The performance of proposed controller was demonstrated through response results. The results confirm that the proposed controller is high performance and robust under the variation of load torque and parameters.

• Journal of the Korean Institute of Navigation
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• v.14 no.2
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• pp.15-31
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• 1990

Recently, there is a tendency to design the large full ships with lower-powered engine as the means for energy saving in ship's navigation at seas. Such a lower-powered ship is anticipated to show the different propulsive performance in rough seas, because the fluctuation of main engine load of lower powered ship is relatively large as compared with higher-powered ship is relatively large as compared with higher-powered ship. The fluctuation of propeller load is nonlinear at racing condition in waves. It is due to the variation of inflow velocity into propeller, the propeller immersion and the characteristics of engine governor. In this paper, the theoretical calculation of the nominal speed loss and the numerical simulation for the nonlinear load fluctuation of a model ship in rough seas are carried out. From the results of calculation, the following are discussed. (1) The ratio of nominal speed loss to the speed in still water. (2) The manoeuvring ability of ship and the operational ability of main engine in a seaway. (3) A method of the evaluation for the fluctuation of propeller torque and revolution on the engine characteristics plane. (4) The effect of engine governor characteristics on the propeller load fluctuation.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.1
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• pp.88-94
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• 2000

In this paper, a parameter estimation method for a vector control of induction motors is presented. It can be easily implemented to the inverters in the industrial fields such as continuous process line, which requires the high performance of torque control, because of being estimated under the condition of the actual operating states. Also, this method nems no additional hardware such as voltage sensors and measuring equipments by the estimation of output voltage, and has good accuracy and repeatability by observing the variation of the stator voltage due to estimation errors. Experimental results verify the validity and usefulness of the proposed estimation method in the industrial fields.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.18-24
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• 2013

An experimental study was performed to investigate the characteristics of combustion pressure and exhaust emissions when the pilot injection timing and EGR rate were changed in a CRDI 4-cylinder diesel engine. The pilot injection timing and EGR rate have a significant impact on the combustion and emission characteristics of diesel engine. In this study, the pilot injection timing and EGR rate variation were conducted to 2000rpm of engine speed with torque 50Nm. Combustion pressure and heat release rate were decreased under high EGR rate conditions but increased under the pilot injection timing $20^{\circ}$(BTDC). IMEP and the maximum pressure in cylinder(Pmax) were decreased under the same injection timing with the increase of EGR rate. The NOx emission was decreased with increasing the EGR rate. On the other hand, in the same injection timing conditions, CO, HC, $CO_2$ emissions were increased with increasing the EGR rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1978-1983
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• 2011

BLDC motor is used in a wide variety of industrial and servo applications. Its features and advantages mainly consist in high value of torque/inertia ratio, high efficiency with speed range and high dynamic performance. This paper deals with the speed control of a trapezoidal type brushless DC motor using Fuzzy PI controller. The conventional PI controller has been widely used in industrial applications. If we select a optimal PI control gain, the PI controller shows very good control performance. But it is very difficult to find the optimal PI control gain. Fuzzy control does not need any model of plant and is basically adaptive and gives robust performance for plant parameter variation. Therefore the combinations of conventional PI controller and fuzzy controller seem to be very effective. This paper deals with PI controller with 4-rule based fuzzy controller. The proposed fuzzy PI controller increases the control performance of the conventional PI controller. Simulation and experimental results show that fuzzy PI controller has a good robustness regarding the improper tuned PI controller.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.703-710
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• 2010

Recently, small hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable turbine type is not determined yet in the range of small hydropower and it is necessary to study for the effective turbine type. Therefore, a 80kW-Class cross-flow turbine is adopted in this study because of its simple structure and high possibility of applying to small hydropower. The result shows that as effective head increases, tangential and radial flow velocities increase and thus, the increased tangential velocity contributes to the increase of angular momentum and output torque.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.521-524
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• 2009

This study describes aerodynamic noise of high speed wind turbine system, which is invented as a new concept in order to reduce the torque of main shaft, for design parameters of the rotor blade. For parametric study of high speed rotor aerodynamic noise, Unsteady Vortex Lattice Method with Nonlinear Vortex Correction Method is used for analysis of wind turbine blade aerodynamic and Farassat1A and Semi-Empirical are used for low frequency noise and airfoil self noise. Parameters are chord length, twist and rotational speed for this parametric research. In the low frequency range, the change of noise is predicted the same level as each parameters varies. However, in case of broadband noise of blade, the change of rotational speed makes more variation of noise than other parameters. When the geometric angles of attack are fixed, as the rotational speed is increased by 5RPM, the noise level is increased by 4dB.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.234-241
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• 2002

In this study, the car crash analysis that simulates the crushing behavior of car forestructure during a frontal impact is carried out. The analysis model for front impact of a car consists of the lumped mass and the spring model. The characteristics value of masses and springs is obtained from the static analysis of a target car. The deceleration-time curve obtained from the simulation are compared with NCAP test data from the NHTSA. They show a good agreement with frontal crash test data. The deceleration-time curve of passenger compartment is classified into 3 stages; beginning stage, middle stage, and last stage. And the behavior of masses at each stage is explained. The effect of stiffness variation on deceleration of passenger compartment is resolved. The maximum loaded peak-time of torque box and dash is the main factor to control the passenger compartment's maximum deceleration.