• Journal of Advanced Marine Engineering and Technology
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• 제24권1호
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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.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.65-70
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• 2003

In this paper, an adapted TWC model and its application to the monitoring algorithm are proposed. As TWCs have the different characteristics, the model has to be corrected to diagnose more accurately. In the TWC model oxygen storage and release rate model are adapted to the installed TWC to whose characteristics related. The model learns from the downstream $O_2$ sensor output during the vehicle's operation. From the results, the model is adapted to the Installed TWC's characteristics. using this model, the monitoring algorithm can diagnose the no more accurately. Finally the algorithm is validated with simulations using the data logged from a retail car.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.371-377
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• 2009

Backfire characteristics for hydrogen fueled free piston engine with uni-flow scavenging is investigated with different stroke, exhaust vlave openning timing and fuel-air equivalence ratio by using RICEM (Rapid Intake Compression Expansion Machine) for combustion research of free piston engine. As results, it is found that backfire can be occurred due to slow combustion of unhomogeneous mixture in the piston crevice volume or/and in the cylinder near piston head. And the more stroke of free piston H2 engine with uni-flow scavenging is short the more opening timing of exhaust valve have to be advanced to control backfire.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.47-55
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• 1998

A new ignition system concept was developed to improve ignition performance, accuracy of control and the reliability of the ignition system. The new ignition system has ho호 frequency discharge characteristics with 1.5-2.0 ms discharge duration, in place of the usual solitary longer duration event. We applied the system to a commercial engine to study its influence on the maximum combustion pressure attained during the cycle, when this peak pressure occurred, imep, variation rate of the engine speed and the flammability limit of a lean mixture. In this study, we clarified that the new ignition system had a beneficial effect of the lean mixture flammability limit. Also for a given mixture strength we found that the mew ignition system gave a higher peak cylinder pressure than in the case of the conventional ignition system.

• 대한기계학회논문집B
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• 제36권4호
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• pp.413-418
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• 2012

본 연구에서는 VIStA (Vortex Inertial Staged Air) 버너를 개조하여 관류보일러에 적용하였다. 2차 공기를 노즐을 통해 공급하던 원형과 달리 선회기를 통해 공급함으로써 화염을 안정화하고 일산화탄소(CO)의 발생량을 저감하였다. 그러나, 이러한 개조과정에서 질소산화물(NOx)의 발생이 증가하는 문제가 발생하였다. CO와 NOx 발생량을 함께 제어하기 위하여 본 연구에서는 화염분할을 적용하였다. VIStA 버너는 2개의 연소실이 있고 각각의 연소실에 공급되는 공기량을 댐퍼로 조절하며 3가지 종류의 화염분할 장치를 설계, 장착하여 공기비, 연소부하에 따른 연소 특성을 파악하였다. 화염분할을 통하여 CO 농도 증가는 10 ppm 이내로 유지하면서 NOx의 발생량은 25%까지 저감하는 결과를 얻었다.

• 대한기계학회논문집B
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• 제34권5호
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• pp.547-552
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• 2010

본 연구에서는 VIStA(Vortex Inertial Staged Air) 버너를 개조하여 관류보일러에 적용하였다. 개조는 크게 2가지 부분에서 이루어 졌는데, 먼저 원형에서 채택한 예혼합 연소 방식을 사용상 편의와 안전을 위해 비예혼합방식으로 변경하였다. 연소 방식의 변경에 따라 공기 1차, 2차에 별도의 송풍기를 사용하던 공급 방식도 변경하여 본 연구에서는 하나의 송풍기로부터 공기를 공급받아 댐퍼를 통하여 1, 2차 연소실에 분할하여 공기를 공급하도록 하였다. 본 연구에서는 질소 산화물(NOx)의 생성을 억제하는 최적의 운전 조건을 찾기 위하여 전체 공기비 및 1, 2차 연소실로의 공기 분배 비율에 따른 NOx 생성 특성을 관찰하였다. 본 연구에서 산업용 보일러에 적용하기 위해 개조한 비예혼합 방식의 VIStA 버너를 설치한 결과, 기존의 일반 버너에 비해 균일한 화염을 얻었고 질소 산화물을 최대 20%까지 줄일 수 있는 것을 확인하였다.

• 제어로봇시스템학회논문지
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• 제13권2호
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• pp.179-186
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• 2007

This paper presents new ignition method and ignition recognition logic for a microturbine. New ignition method is designed by constant speed control of a microturbine with pre-determined time during a ignition period. It make more accurate air-fuel ratio as well as give enough time to ignition system to have full performance under cold temperature. And ignition recognition logic is designed by observing output current change of inverter by generating output torque of a microturbine in the instant of ignition. For filtering a output torque current of inverter with high frequency, we applied a moving average method. So far, ignition recognition is usually implemented by measuring of exhausted gas temperature(EGT) of microturbine. The proposed logic can give more accurate judgement of ignition as well as keep a good working of starting system under out of order a temperature measuring system and biased initial value of EGT sensor. Finally, the two proposed logics are proved by field operating a microturbine under various conditions.

• 한국분무공학회지
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• 제16권3호
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• pp.134-139
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• 2011

Recent research has focused on engine combustion technology as well as application of after-treatment in order to comply with emission regulation. However, it is much more efficient way to control emissions from engine itself and furthermore research on engine control will provide the direction of after-treatment technology in future. Furthermore, emission standard regulation for passenger diesel vehicles has been stringent compared to others and nano-particles will be included in EURO6 regulation in Europe and similar emission standard will be introduced in Korea. A 3.0 liter high speed diesel engine equipped with by CRDI system of 160MPa injection pressure, and an intake/exhaust system of V type 6 cylinder turbo-intercooler was applied. The injection duration and injection quantity, pilot injection types which are related to CRDI and air/fuel ratio control applied by EVGT were changed simultaneously. Standard experiment procedure constituted dilution apparatus and CPC system to collect nano-particles and these test results were compared with regulated materials of CO, HC, NOx and investigated their relations and characteristics of nano-particles.

• 한국항행학회논문지
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• 제14권1호
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• pp.93-101
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• 2010

본 논문에서는 터보차저 엔진에서 중요한 문제로 대두되는 응답 특성을 규명하고, 전 부하뿐만 아니라 빈번하게 운행되는 부분 부하 조건 하에서의 엔진 성능을 분석하고자 한다. 시험 결과 컴프레서의 압축비는 1260 rpm 까지는 직선 형태로 급격히 증가하고 이후에는 약 2.5 정도로 완만하게 증가하는 것으로 나타났다. 이때 제동 평균 유효 압력도 압축비에 따라 1260 rpm 까지는 직선적으로 급격하게 증가하다가 1600 rpm 이후부터는 급격히 감소하였다. 과급압이 증가될수록 연비, 공기 과잉률, 제동 평균 유효 압력이 향상되나 중저속 영역보다는 정격 회전수로 갈수록 높아지는 경향이 크게 나타나고 있다. 터보차저는 약 1260 rpm 에서부터 안정적으로 작동되는 것으로 나타났으며 저속 영역에서는 과급기의 특성상 효율이 낮게 나타났다. 이 연구의 결과는 터보차저 엔진의 안정적 부하와 속도 제어 방법에 응용할 수 있다.

• 대한기계학회논문집B
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• 제21권4호
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• pp.518-524
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• 1997

Experimental studies on combustion phenomena within a porous ceramic burner are reported. Main interest of the present work is to investigate fundamental flame behaviors and their effects on the burner operation. Due to high thermal capacity of the porous ceramic materials, the response of flame to burning condition changes is slow and thus to have a stabilized flame is quite difficult and takes much time. It is found that the temperature profile obtained at downstream of the flame zone is not much sensitive to the movement of flame and the speed of flame movement is less than 0.1 mm/sec for the conditions tested. With the premixed LPG/air flame imbedded within the porous ceramic burner, stable combustion regions and unstable combustion regions leading to blowoff or flashback phenomena are observed and mapped on flow velocity versus equivalence ratio diagram. For the development of burner operation technique which is more practical and safe, intermittent burning technique, where the fuel or/and air is supplied to the burner intermittently, is proposed as one of the flame control methods for the porous ceramic burner and tested in this study. Through the experiment, it is realized that the proposed method is acceptable in respect to burner performance and give much flexibility in the operation of porous ceramic burner.