• 제목/요약/키워드: post-combustion

검색결과 128건 처리시간 0.027초

후진동이 나타나는 실화 진단 방법에서 가중치를 이용한 성능 향상에 대한 연구 (A Study on the Improvement of Misfire Detection Method with Vibration by using the Weight Factor)

  • 임지훈;이태연;김일구;홍성률;성진호;박재홍;윤형진;박진서;김동선
    • 한국자동차공학회논문집
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    • 제13권4호
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    • pp.74-80
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    • 2005
  • This paper presents a misfire monitoring method by using the weight factor. According to OBD II(On-Board Diagnostics) regulations of the CARB (California Air Resources Board), an ECU (Electronic Control Unit) should detect misfires which occur in the internal combustion engine. A misfire is 1311owe4 by post-oscillations for short duration. Sometimes, the amplitude of oscillations may be as high as misfire and can be falsely detected as another misfire. To prevent this, the software designers do not attempt to detect another misfire for this short duration, during which the post oscillations exist. Because of this, ECU does not detect all the misfires and hence, the unstable state of automobile cannot be detected. If this happens for a long time, automobile may get damaged. To solve these problems, this paper suggests a new algorithm to detect misfire by using weighting factor Weighting factor is a concept to distinguish the misfire with the post oscillation and to improve the detection rate. This value of weighting factor is used for counting the misfire. This paper also shows the result of experiment done on a automobile using this software. The software is implemented using ASCET-SD which is preferred in the design of engine control. This paper's result show the possibility of improving the misfire detection by implementing this algorithm.

고효율 X선 검출기 적용을 위한 PbO 필름 제작 및 특성 연구 (Fabrication and Characterization of Lead Oxide (PbO) Film for High Efficiency X-ray Detector)

  • 조성호;강상식;최치원;권철;남상희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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    • pp.329-329
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    • 2007
  • Photoconductive poly crystalline lead oxide coated on amorphous thin film transistor (TFT) arrays is the best candidate for direct digital x-ray detector for medical imaging. Thicker films with lessening density often show lower x-ray induced charge generation and collection becomes less efficient. In this work, we present a new methodology used for the high density deposition of PbO. We investigate the structural properties of the films using X-ray diffraction and electron microscopy experiments. The film coatings of approximately $200\;{\mu}m$ thickness were deposited on $2"{\times}2"$ conductive-coated glass substrates for measurements of dark current and x-ray sensitivity. The lead oxide (PbO) films of $200\;{\mu}m$ thickness were deposited on glass substrates using a wet coating process in room temperature. The influence of post-deposition annealing on the characteristics of the lead oxide films was investigated in detail. X-ray diffraction and scanning electron microscopy, and atomic force microscopy have been employed to obtain information on the morphology and crystallization of the films. Also we measured dark current, x-ray sensitivity and linearity for investigation of the electrical characteristics of films. It was found that the annealing conditions strongly affect the electrical properties of the films. The x-ray induced output charges of films annealed in oxygen gas increases dramatically with increasing annealing temperatures up to $500^{\circ}C$ but then drops for higher temperature anneals. Consequently, the more we increase the annealing temperatures, the better density and film quality of the lead oxide. Analysis of this data suggests that incorporation and decomposition reactions of oxygen can be controlled to change the detection properties of the lead oxide film significantly. Post-deposition thermal annealing is also used for densely film. The PbO films that are grown by new methodology exhibit good morphology of high density structure and provide less than $10\;pA/mm^2$ dark currents as they show saturation in gain (at approximate fields of $4\;V/{\mu}m$). The ability to operate at low voltage gives adequate dark currents for most applications and allows voltage electronics designs.

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터보펌프 터빈의 열구조적 적합성 검증을 위한 터빈로터-파이로시동기 연계시험 (Turbine Rotor-Pyrostarter Coupled Test for the Verification of Thermo-Structural Suitability of a Turbopump Turbine)

  • 정은환;강상훈;홍문근;이항기;이수용;김진한
    • 한국추진공학회지
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    • 제18권1호
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    • pp.65-72
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    • 2014
  • 터보펌프 터빈로터의 열구조적 적합성 검증을 위한 터빈로터-파이로시동기 연계시험을 수행하였다. 새로운 추진제를 적용한 파이로시동기와 열응력 경감 설계 및 터빈 동익 표면 건전성 향상을 위한 후 가공 공정이 적용된 터빈로터시편이 시험에 사용되었다. 시험은 75톤급 엔진시동을 위한 파이로 시동기의 연소가스를 터보펌프 터빈로터와 동일한 형상의 시편에 분사하는 방식으로 이루어졌다. 터빈에 가해지는 열 부하는 운용 설계점에서 극한 조건까지 세 종류로 구분하여 시험을 진행하였으며 모든 시험에서 터빈로터의 손상은 발견되지 않았다.

A study of improving filtration efficiency through SiC whisker synthesis on carbon felt by CVD VS method

  • 김광주;최두진
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.150-150
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    • 2016
  • Mankind is enjoying a great convenience of their life by the rapid growth of secondary industry since the Industrial Revolution and it is possible due to the invention of huge power such as engine. The automobile which plays the important role of industrial development and human movement is powered by the Engine Module, and especially Diesel engine is widely used because of mechanical durability and energy efficiency. The main work mechanism of the Diesel engine is composed of inhalation of the organic material (coal, oil, etc.), combustion, explosion and exhaust Cycle process then the carbon compound emissions during the last exhaust process are essential which is known as the major causes of air pollution issues in recent years. In particular, COx, called carbon oxide compound which is composed of a very small size of the particles from several ten to hundred nano meter and they exist as a suspension in the atmosphere. These Diesel particles can be accumulated at the respiratory organs and cause many serious diseases. In order to compensate for the weak point of such a Diesel Engine, the DPF(Diesel Particulate Filter) post-cleaning equipment has been used and it mainly consists of ceramic materials(SiC, Cordierite etc) because of the necessity for the engine system durability on the exposure of high temperature, high pressure and chemical harsh environmental. Ceramic Material filter, but it remains a lot of problems yet, such as limitations of collecting very small particles below micro size, high cost due to difficulties of manufacturing process and low fuel consumption efficiency due to back pressure increase by the small pore structure. This study is to test the possibility of new structure by direct infiltration of SiC Whisker on Carbon felt as the next generation filter and this new filter is expected to improve the above various problems of the Ceramic DPF currently in use and reduction of the cost simultaneously. In this experiment, non-catalytic VS CVD (Vapor-Solid Chemical Vaporized Deposition) system was adopted to keep high mechanical properties of SiC and MTS (Methyl-Trichloro-Silane) gas used as source and H2 gas used as dilute gas. From this, the suitable whisker growth for high performance filter was observed depending on each deposition conditions change (input gas ratio, temperature, mass flow rate etc.).

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피부에 폭로된 폐가솔린엔진오일의 표적장기 DNA adducts형성과 케로신의 세척효과에 관한 연구 (Adverse Effects of Kerosene Cleaning on the Formation of DNA Adducts in Skin and Lung of Mice Dermally Exposed to Used Gasoline Engine Oil)

  • 이진헌;그린 탈라스카
    • 한국산업보건학회지
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    • 제8권2호
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    • pp.289-295
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    • 1998
  • Used gasoline engine oils(UGEO) are carcinogenic in long term studies and capable of increasing the number of carcinogen-DNA adducts in short term studies when dermally applied to mice. The carcinogenic risk of UGEO has been attributed to the concentration of polycyclic aromatic hydrocarbons(PAH) which accumulate in the lubricating system during the combustion of gasoline. When dermally exposed to UGEO, the use of hand cleanser was commonly recommended for removing it. But generally workers who dermally exposed oils, use kerosene as cleaner which make skin trouble. During this study, female mice aged 4-6 weeks were utilized to evaluate the efficiency of kerosene, as solvent-based cleanser, following dermal exposure to UGEO. DNA adduct were detected at skin and lung tissues by using the $^{32}P$-postlabeling method. Washing with cleansers were done at two different interval times following dermal application of UGEO. The total DNA adducts in skin and lung tissues were statistically significantly increased in positive control groups, and of which the total adduct level in skin tissues was statistically significant higher than those in lung tissues(p=0.005). When washing kerosene, the DNA adduct level in skin tissues was statistically significantly decreased(p=0.0001). But DNA adducts in lung tissue was statistically increased(p=0.0039), and that washed at 8hr post exposure was more severly increase(p<0.05). The slope of regression between DNA adducts of lung between skin tissues was 1.0802. In conclusion, skin cleaning with kerosene facilitates passage of carcinogens to the lungs of animals dermally treated with used gasoline engine oils(UGEO).

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정상초음파의 교란을 받는 메탄-공기 예혼합화염의 전파특성에 대한 초음파 구동 주파수의 영향 (Effects of Driving Frequency on Propagation Characteristics of Methane-Air Premixed Flame Influenced by Ultrasonic Standing Wave)

  • 배대석;서항석;김정수
    • 대한기계학회논문집B
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    • 제39권2호
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    • pp.161-168
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    • 2015
  • 정상초음파장의 구동 주파수가 메탄-공기 예혼합화염의 전파특성에 미치는 영향을 규명하고자 하는 실험결과를 제시한다. 고속카메라를 이용하여 화염의 전파영상을 획득하였으며, 영상 후처리를 통해 화염선단의 구조와 속도변이를 포함하는 화염의 거시적 거동을 상세히 관찰하였다. 정상초음파가 연소반응을 촉진시켜 화염 전파속도의 증대와 화염선단 구조의 변이를 유발한다는 사실에 더하여, 초음파구동 주파수와 당량비에 대한 화염거동의 종속성을 확인하였다.

대면적 Fecralloy 코팅층의 표면 거침도 극대화를 위한 정전분무 및 열처리 공정 연구 (Electrospray and Thermal Treatment Process for Enhancing Surface Roughness of Fecralloy Coating Layer on a Large Sized Substrate)

  • 이혜문;구혜영;양상선;박다희;정수호;윤중열
    • 한국분말재료학회지
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    • 제24권1호
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    • pp.46-52
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    • 2017
  • Fecralloy coating layer with large surface area is suitable for use as a filter media for efficient removal of hot gaseous pollutants exhausted from combustion processes. For uniform preparation of a Fecralloy coating layer with large surface area and strong adhesion to substrate, electrospray coating and thermal treatment processes are experimentally optimized in this study. A nano-colloidal solution with 0.05 wt% Fecralloy nanoparticles is successfully prepared. Optimized electrospraying conditions are experimentally discovered to prepare a uniform coating layer of Fecralloy nano-colloidal solution on a substrate. Drying the electrospray coated Fecralloy nano-colloidal solution layer at $120^{\circ}C$ and subsequent heating at $600^{\circ}C$ are the best post-treatment for enhancing the adhesion force and surface roughness of the Fecralloy coating layer on a substrate. An electrospray coating system, consisting of several multi-groove nozzles, is also experimentally confirmed as a reasonable device for uniform coating of Fecralloy nano-colloid on a large area substrate.

방염처리 방법에 따른 MDF 목재의 방염성능에 관한 연구 (A Study on the Flame Retardant Performance of MDF Wood According to Flame Retardant Treatment Method)

  • 차정민;현성호;김인범;윤명오
    • 한국화재소방학회논문지
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    • 제25권6호
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    • pp.146-155
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    • 2011
  • 본 연구에서는 현장방염처리(방염후처리)가 적용되고 있는 MDF 목재에 국내에서 유통되는 5개사 제품을 MDF 목재에 부착한 방염필름과 MDF 목재(무처리, 비방염필름)에 수성 유성 방염도료로 도포된 시편을 대상으로 현재 시중에서 사용되고 있는 방염처리 방법에 따라 방염성능을 비교하는 실험을 실시하였다. MDF 목재에 5개사의 방염필름을 부착하여 연소 시험한 결과 2개사 제품은 4가지 기준 내에 적합한 값을 나타냈으나 나머지 3개사 제품은 10~40 %의 불합격률을 나타냈다. 방염도료의 특성별로는 유성방염도료가 수성방염도료보다 방염성능 기준 내에서는 더 우수한 것으로 나타났지만 유성방염도료를 도포한 MDF 목재에서 수성방염도료를 도포한 MDF 목재에서 보다 독성지수의 위험등급은 상대적으로 더 높은 위험도를 나타내었다.

DeSOx/DeNOx 효율 개선을 위한 펄스 코로나 방전하에서 기체미립자 전환반응의 적용 (Application of Gas to Particle Conversion Reaction to increase the DeSOx/DeNOx Efficiency under Pulsed Corona Discharge)

  • 최유리;김동주;김교선
    • 산업기술연구
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    • 제18권
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    • pp.249-258
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    • 1998
  • In this paper, we investigated the post-combustion removal of nitrogen oxide($NO_x$) and sulfur oxide($SO_x$) which is based on the gas to particle conversion process by the pulsed corona discharge. Under normal pressure, the pulsed corona discharge produces the energetic free electrons which dissociate gas molecules to form the active radicals. These radicals cause the chemical reactions that convert $SO_x$ and $NO_x$ into acid mists and these mists react with $NH_3$ to form solid particles. Those particles can be removed from the gas stream by conventional devices such as electrostatic precipitator or bag filter. The reactor geometry was coaxial with an inner wire discharge electrode and an outer ground electrode wrapped on a glass tube. The simulated flue gas with $SO_x$ and $NO_x$ was used in the experiment. The corona discharge reactor was more efficient in removing $SO_x$ and $NO_x$ by adding $NH_3$ and $H_2O$ in the gas stream. We also measured the removal efficiency of $SO_x$ and $NO_x$ in a cylinder type corona discharge reactor and obtained more than 90 % of removal efficiency in these experimental conditions. The effects of process variables such as the inlet concentrations of $SO_x$, $NH_3$ and $H_2O$, residence time, pulse frequencies and applied voltages were investigated.

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N2O/PE 하이브리드 로켓의 스케일 변화에 따른 연소특성 연구 (Scale Effect on Combustion Characteristics of N2O/PE Hybrid Rocket)

  • 한승주;문근환;김진곤;문희장
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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    • pp.797-802
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    • 2017
  • 본 연구에서는 하이브리드 추진기관 설계에 중요한 변수인 스케일에 따른 연소특성을 분석하였다. Blow-down 시스템을 사용하는 $LN_2O$/PE 추진제 조합에 대하여 분석을 수행하였으며 현존하는 스케일 관계식을 이용한 스케일 변화에 따른 평균 후퇴율의 변화는 크지 않음을 확인하였다. 특성배기속도 효율은 스케일이 커짐에 따라 증가함을 확인하였다. 그러나 특성배기속도 효율은 후방연소실의 형상 등 복잡한 변수가 포함되어 있어 단순한 스케일의 변화에 따른 영향이라고 단정할 수 없다고 판단된다. 이에 특성속도효율 및 국부적인 후퇴율 예측에 관한 하이브리드 로켓 스케일 관계식에 관해서는 확정적인 결론을 도출하기 어려울 것으로 판단된다.

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