• International Journal of Automotive Technology
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• v.4 no.3
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• pp.109-117
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• 2003

The analysis and evaluation of the transient performance by the transient response specifications under various acceleration speeds and types based on driver's typical acceleration habit are implemented by the experimental study to provide the appropriate direction for the transient control in a gasoline engine. The concept of the transient response specifications which consist of delay time, rising time, maximum overshoot and settling time, and the analysis method using them are introduced to evaluate the characteristics of the transient performance quantitatively. Furthermore four acceleration speeds and four acceleration types are set respectively to realize the various transient states which are similar to the real drive. Several performance parameters in terms of engine speed, manifold absolute pressure, fuel injection duration and air excess ratio are measured simultaneously during the various acceleration using a throttle actuator controlled by a PC. The transient response specifications characterized well the transient performance for the various acceleration speed and types quantitatively. Delay and rising time with increment of the acceleration speed became shorter, but settling time did longer. Intensified acceleration type appeared to be the most economical in view of fuel consumption, and linear acceleration type was found to have the least harmful emission concentration.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.75-81
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• 2000

To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration($\DeltatI_{nj}$) and air excess ratio($\lambda$) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

• Journal of Mechanical Science and Technology
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• v.14 no.11
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• pp.1296-1304
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• 2000

A program of steady-state and transient performance analysis for a 200kW-class small turboshaft engine with free power turbine was developed. An existing turbojet engine was used for the gas generator of the developed turboshaft engine, which was modified to satisfy performance requirements of this turboshaft engine. To verify the accuracy of steady-state performance program for this engine: the program was applied to the gas turbine test unit of the same type, and the analysis results were compared with experimental results. The developed transient performance analysis program using the CMF (Constant Mass Flow) method was utilized to analyze the cases of step increase and ramp increase of the fuel.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.28-34
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• 2011

This paper describes the development of the transient analysis model of 345[kV] 100[MVA] STATCOM and the result of the performance analysis. The Korea power utility company, KEPCO began a commercial operation of a 100[MVA] STATCOM(Static synchronous COMpensator) at 345[kV] Migeum substation in Seoul. In order to operate a new control device like STATCOM to the power system, suitable transient model is needed. Therfore, Korea Electric Power Coporation(KEPCO) developed a transient analysis models using EMTDC/PSCAD. The development of this transient analysis model is based on the actual STATCOM S/W algorithm and H/W specification that was provided by its manufacture. Through this model, the transient/dynamic performance of STATCOM at Migeum substation can be analyzed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1455-1460
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• 2014

Wind turbine generators were designed on general regulations of wind condition. At real situations, it could be different from the design conditions. There are many control methods and definitions of transient region, because an efficient wind turbine generator control logic is the important matter in generator performance and annual energy production at real conditions. In this document, the power generation sensitivity for wind speed and turbulence intensities was defined to know the sensitive transient region. Wind conditions are applied for the ranges of 7~10m/s mean wind speed and 14~20% turbulence intensity. The sensibility of HR-D86 wind generator was increased in transient region(8~10m/s) on power curve diagram through a torque control to a pitch control. And then GH-bladed simulations was performed for performance analysis of the torque mode switching in transient region on 2MW direct drive wind generator(HR-D86) which is designed IEC class II for onshore. Through the sensitivity and performance analysis, the sensitivity for real wind condition could be the performance index for an wind generator. And the torque mode switching in transient region can increase the mean power generation on HR-D86 wind turbine generator.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.81-90
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• 1999

The performance evaluation technique of a heat exchanger is described by using a transient response analysis for the determination of an average heat transfer coefficient. The model using a finite difference method can accommodate arbitrary inlet fluid temperature as well as longitudinal conduction. Temperature histories are obtained from the experiments at the inlet and outlet of test core. Heat transfer coefficient and friction factor of the plate array are obtained in short times using the data reduction program of transient response analysis in the single-blow method. The results agree very well with theoretical results. It is shown that the rms deviations are very small and the performance evaluation technique gives rapid and accurate results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2060-2066
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• 2002

The closed-loop state and input observer is a pole-placement type observer and estimates unknown state and input variables simultaneously. Pole-placement type observers may have poor transient performance with respect to ill-conditioning factors such as unknown initial estimates, round-off error, etc. For the robust transient performance, the effects of these ill-conditioning factors must be minimized in designing observers. In this paper, the transient performance of the closed-loop state and input observer is investigated quantitatively by considering the error bounds due to ill-conditioning factors. The performance indices are selected from these error bounds and are related to the observer robustness with respect to the ill -conditioning factors. The closed-loop state and input observer with small performance indices is considered as a well-conditioned observer from the transient perspective.

• 연구논문집
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• s.30
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• pp.5-13
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• 2000

The computation scheme of simulating gas turbine transient behavior was developed. The basic principles of this scheme and main input data required are described. Calculation results are presented in terms of whole operating regime of the cycle. The influence of main initial parameters such as starting engine power, moment of inertia of the rotor, fuel supplying schedule etc. on performance characteristics of has turbine during transient operation is studied In addition, bleeding air influence on transient behavior was also considered For validation of the developed code, comparison of present calculation with that of measurement data of the experimental data for the range of operating period studied.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2094-2099
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• 2008

A numerical and experimental studies are carried out to investigate the transient heat transfer characteristics of 5kWth dish-type solar air receiver. Measured solar radiation and temperatures at several different locations are used as boundary conditions for numerical simulation. Many parameters' effects (reflectivity of the reflector, the thermal conductivity of the receiver body, transmissivity of the quartz window, etc.) on the thermal performance are investigated. Discrete Transfer Method is used to calculate the radiation heat exchange in the receiver. A transient heat transfer model is developed and the rate of radiation, convection and conduction heat transfer are calculated. Comparing the experimental and numerical results, good agreement is obtained. Using the numerical model, the transient heat transfer characteristics of volumetric air receiver for dish-type solar thermal systems are known and the transient thermal performance of the receiver can be estimated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.9
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• pp.71-77
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• 2020

In recent years, as a consequence of the technological advancements in the automobile industry and changes in consumer demands, the reduction of noise inside vehicles rather than vehicle performance has increasingly become an important factor of interest. To date, most studies have focused on noise and vibration reduction techniques for the engine and drive system of vehicles. In this research, a comparative analysis for reducing the effect of vehicle seatbelts on the transient response is performed using the test of vehicle conditions and transient response analysis in accordance with seatbelt conditions. After the sensitivity analysis, the specifications for improvement were designed based on the transient response analysis. It was confirmed that the transient response characteristics were improved by the transient response analysis and vehicle conditions test. Through computer-aided engineering, the transient response characteristics of seatbelts were checked with less cost and time.