• Title/Summary/Keyword: transient

Search Result 8,345, Processing Time 0.038 seconds

TRANSIENT PERFORMANCE OF AN SI ENGINE BY TRANSIENT RESPONSE SPECIFICATIONS

  • Kwark, J.H.;Jeon, C.H.;Chang, Y.J.
    • International Journal of Automotive Technology
    • /
    • v.4 no.3
    • /
    • pp.109-117
    • /
    • 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.

Recurrent transient amnesia: a case of transient epileptic amnesia misdiagnosed as transient global amnesia

  • Kihoon Shin;Ki-Hwan Ji
    • Annals of Clinical Neurophysiology
    • /
    • v.25 no.2
    • /
    • pp.103-105
    • /
    • 2023
  • Transient epileptic amnesia and transient global amnesia both exhibit temporary memory loss. The lack of clues of epileptic events and the absence of epileptiform abnormalities in electroencephalography, a clear brain lesion, and interictal cognitive decline can make diagnoses challenging. Here we present a middle-aged female who experienced long-term recurrent transient epileptic amnesia with subtle epileptic features over a period of 3 years.

Effect on Transient Performance of Driver's Acceleration Type in MPI Gasoline Engine (운전자의 가속타입이 MPI 가솔린엔진의 과도성능에 미치는 영향)

  • 곽지현;전충환;장영준
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.24 no.1
    • /
    • pp.75-81
    • /
    • 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.

  • PDF

Transient Diagnosis and Prognosis for Secondary System in Nuclear Power Plants

  • Park, Sangjun;Park, Jinkyun;Heo, Gyunyoung
    • Nuclear Engineering and Technology
    • /
    • v.48 no.5
    • /
    • pp.1184-1191
    • /
    • 2016
  • This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA). This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.

A Study on the Transient Phenomenon Protection System Development for Fire Alarm System Control Unit (화재 수신기용 과도현상 보호시스템 개발에 관한 연구)

  • Lee, Dong-Myung
    • Fire Science and Engineering
    • /
    • v.23 no.2
    • /
    • pp.55-61
    • /
    • 2009
  • This study has been carried on the transient phenomenon protection system to become fire alarm system control unit of high reliance which can be protected from transient phenomena for surge or transient overvoltage, and constructed engineering base that can develop transient phenomenon protection system by proving performance of protection system in a experimental. This study developed 1 step and 2 step protection system that can be protected from transient phenomenon with process thesis and theory for development of transient phenomenon protection system. It established engineering data construction and a source technology that can develop transient phenomenon protection system as gets satisfied result and test with all performance condition that present in fire protection law and connection regulation.

Capless Low Drop Out Regulator With Fast Transient Response Using Current Sensing Circuit (전류 감지 회로를 이용한 빠른 과도응답특성을 갖는 capless LDO 레귤레이터)

  • Jung, Jun-Mo
    • Journal of IKEEE
    • /
    • v.23 no.2
    • /
    • pp.552-556
    • /
    • 2019
  • This paper present a capless low drop out regulator (LDO) that improves the load transient response characteristics by using a current regulator. A voltage regulator circuit is placed between the error amplifier and the pass transistor inside the LDO regulator to improve the current characteristics of the voltage line, The proposed fast transient LDO structure was designed by a 0.18 um process with cadence's virtuoso simulation. according to test results, the proposed circuit has a improved transient characteristics compare with conventional LDO. the simulation results show that the transient of rising increases from 1.954 us to 1.378 us and the transient of falling decreases from 19.48 us to 13.33 us compared with conventional capless LDO. this Result has improved response rate of about 29%, 28%.

Transient Stability Analysis of Power System by Transient Energy Method (과도에너지법에 의한 전력계통의 과도안정도 해석에 관한 연구)

  • 김준현;설용태
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.32 no.2
    • /
    • pp.59-64
    • /
    • 1983
  • This paper deals with the transient energy method of transient stability analysis of multi-machine power system by improving the transfer conductance, the kinetic energy and the critical transient energy. The tranfer conductance is considered more correctly, the generators of system are seperated to two states (critical and the rest state)and the correction term of critical transient energy (to reference point) is added. This analysis is performed by digital computer simulation and the application of this method to two model systems has shown its superiority to other available methods.

  • PDF

DETERMINATION OF TRANSIENT WEAR DISTANCE IN THE ADHESIVE WEAR OF A6061 ALUMINIUM ALLOY REINFORCED WITH ALUMINA PARTICLES

  • Yang, L.J.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 2002.10b
    • /
    • pp.217-218
    • /
    • 2002
  • An integrated adhesive wear model was proposed to determine the transient wear and steady-state wear of aluminium alloy matrix composites. The transient wear volume was described by an exponential equation, while the steady-state wear was governed by a revised Archard equation, in which both the transient wear volume and transient sliding distance were excluded. A mathematical method was developed to determine both the transient distance and the net steady-state wear coefficient. Experimental wear tests were carried out on three types of commercial A6061 aluminum alloy matrix composites reinforced with 10%, 15% and 20% alumina particles. More accurate wear coefficient values were obtained with the proposed model. The average standard wear coefficient, as determined by the original Archard equation, was found to be about 51% higher.

  • PDF

HMM-Based Transient Identification in Dynamic Process

  • Kwon, Kee-Choon
    • Transactions on Control, Automation and Systems Engineering
    • /
    • v.2 no.1
    • /
    • pp.40-46
    • /
    • 2000
  • In this paper, a transient identification based on a Hidden Markov Model (HMM) has been suggested and evaluated experimentally for the classification of transients in the dynamic process. The transient can be identified by its unique time dependent patterns related to the principal variables. The HMM, a double stochastic process, can be applied to transient identification which is a spatial and temporal classification problem under a statistical pattern recognition framework. The HMM is created for each transient from a set of training data by the maximum-likelihood estimation method. The transient identification is determined by calculating which model has the highest probability for the given test data. Several experimental tests have been performed with normalization methods, clustering algorithms, and a number of states in HMM. Several experimental tests have been performed including superimposing random noise, adding systematic error, and untrained transients. The proposed real-time transient identification system has many advantages, however, there are still a lot of problems that should be solved to apply to a real dynamic process. Further efforts are being made to improve the system performance and robustness to demonstrate reliability and accuracy to the required level.

  • PDF

Transient Response Characteristics of Vehicle Seatbelt (자동차 시트벨트의 과도응답 특성에 관한 연구)

  • Kim, Chang-Hee;Lee, Seok-Soon
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.19 no.9
    • /
    • pp.71-77
    • /
    • 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.