• 제목/요약/키워드: Air injection

검색결과 1,200건 처리시간 0.029초

EFFECTS OF SPLIT INJECTION AND OXYGEN-ENRICHED AIR ON SOOT EMISSIONS IN A DIESEL ENGINE

  • Nguyen, Khai;Sung, Nak-Won;Lee, Sang-Su
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2965-2970
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    • 2008
  • Effects of split injection and oxygen-enriched air on soot emissions in a DI diesel engine were studied by the KIVA-3V code. When split injection is applied, the second injection of fuel into a cylinder results in two separate stoichiometric zones which increases soot oxidation. As a result, soot emissions are decreased with split injection. When oxygen-enriched air is applied together with split injection, higher concentration of oxygen helps secondary combustion which results in a higher temperature in the cylinder. The increased temperature promotes growth reaction of acetylene with soot but doesn't improve the acetylene formation during the second injection of fuel. As more acetylene is consumed in the growth reaction of acetylene, the net acetylene mass in the cylinder is decreased, which leads to a decrease of soot formation. With an increase of soot oxidation caused by split injection, the soot emissions are decreased significantly. However, to avoid excessive NOx emissions with increased oxygen concentration, the level of oxygen concentration should be lower than 22% in volume.

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ANALYSIS AND OPTIMIZATION of INJECTION TIMING for AN ADVANCED COMPRESSED AIR ENGINE KIT

  • Kumar, Akshay;Kumar, Vasu;Gupta, Dhruv;Kumar, Naveen
    • International journal of advanced smart convergence
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    • 제4권1호
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    • pp.54-63
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    • 2015
  • Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

Numerical Study on the Air-Cushion Unit for Transportation of Large-Sized Glass Plate

  • Jun, Hyun-Joo;Kim, Kwang-Sun;Im, Ik-Tae
    • 반도체디스플레이기술학회지
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    • 제6권1호
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    • pp.59-64
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    • 2007
  • Non-contact transportation of a large-sized glass plate using air cushion for the vertical sputtering system of liquid crystal display (LCD) panel was considered. The objective of the study was to design an air pad unit which was composed of multiple injection and exhaust holes and mass flow supplying pipe. The gas was injected through multiple small holes to maintain the force for levitating glass plate. After hitting the plate, the air was vented through exhaust holes. Complex flow field and resulting pressure distribution on the glass surface were numerically studied to design the air injection pad. The exhaust hole size was varied to obtain evenly distributed pressure distribution at fixed diameter of the injection hole. Considering the force for levitating glass plate, the diameter of the exhaust hole of 30 to 40 times of the gas injection hole was recommended.

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소형 공기청정기 하우징의 성형성 향상을 위한 런너시스템 설계 및 스크류 전진 거리 예측 (Design of Runner System and Prediction of Moving Distance of the Screw for the Improvement of Formability of a Housing Part of Small-Size Air Cleaner)

  • 김동인;이호진;안동규
    • 한국정밀공학회지
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    • 제33권12호
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    • pp.1021-1030
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    • 2016
  • The runner system of the injection mould and the injection volume of the injection molding process greatly affect the quality of the produced part. The goal of this paper is the design of the runner system and the prediction of the injection volume for the injection moulding of a housing part of small-size air cleaner to improve the formability through the three-dimensional injection moulding analysis. The effects of the runner system of the mould on the injection moulding characteristics are investigated. From the results of the investigation, a proper design of the runner system with uniform filling characteristics and the minimized defect formation is obtained. In addition, the influence of the moving distance of the screw on filling characteristics, weldline formation and deformation characteristics is examined. From the results of the examination, an appropriate moving distance of the screw for the housing part of small-size air cleaner is estimated.

다단 에어셀 충진 밸브성형기술에 관한 연구 (A Study on the Forming Technology of Multi-stage Aircell Filling Valves)

  • 김미숙;박동삼
    • 한국산학기술학회논문지
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    • 제18권12호
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    • pp.57-64
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    • 2017
  • 오늘날 EU환경규제로 포장용 완충재로 사용되는 EPS(스티로폼) 대체용 공기 충진 완충재는 출시 이후 점진적으로 시장이 확대되는 포장업계 블루칩이다. 공기충진형 완충재는 뛰어난 완충능력과 친환경성으로 EPS를 대체하여 빠르게 시장을 확장하고 있다. 기존 공기 충진 완충재에 대비하여 원료절감과 공정향상, 직관적 미관 향상을 모두 충족하는 새로운 선택 충진형 공기 충진재 제조기술이다. 본 연구는 다단 에어셀 충진 밸브성형기술은 선택충전 기술을 바탕으로, 밸브형성 구조기술을 적용하여 선택적으로 다양한 형태로 충진이 가능한 기술이다. 다단 에어셀 충진 밸브성형기술의 구조도는 밸브단이 구분된 제1주입필름, 밸브필름, 제2주입필름 등 3겹의 필름을 적층하여 복수의 주입구를 형성한 기술이다. 기존의 기술은 연결된 다수의 공기주머니에 공기를 주입하기 위한 별도의 외부 공기주입로가 필수적으로 구성되어야 하나, 본 연구는 공기 주머니의 내부에 외부 공기주입로가 형성되어 공기를 주입하기 위한 외부 공기주입로가 외견상 없어짐으로써 그에 따른 원재료 및 공정이 감소하고, 공기가 주입되어 원형 튜브로 팽창하는 과정에서 단면의 길이가 63~66%로 축소되는 공기주머니와 다르게 공기주입 후 내부 공기가 배출되고 단면이 원래의 길이를 유지하여 불필요하게 접힌 채 붙어 있는 외부 공기주입로를 내부에 일체화 하여 완충재의 미관이 향상되는 기술적 특징과 다수의 연속된 공기주머니에 선택적으로 공기를 충전할 수 있는 선택충전에 관한 것으로 기존 기술대비 뛰어난 차별성을 갖는 스마트한 공기충전형 완충재 제조 기술이다.

말더듬에서 언제 보툴리늄독소주입술이 효과적인가에 관한 연구 (When the Botulinium Toxin Injection Is Effective in Stutters)

  • 안철민
    • 대한후두음성언어의학회지
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    • 제26권1호
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    • pp.46-50
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    • 2015
  • Background and Objectives:Laryngeal hyperkinetic movements of stuttering patients is similar to that of adductor spasmodic dysphonia. There has been studies on implementing botulinium toxin injections to treat stuttering. However, the opinions on the bouolinium toxin injection's effects on stuttering patients vary. In this study authors aim to figure out when the botulinium toxin injection improves stuttering patients. Materials and Methods:Stuttering patients who could receive botulinium toxin injection participated in this study. Age differences, gender differences, electroglottogrphic test, aerodynamic test in botulinium toxin injection treatment of stuttering were analyzed. Results:The botulinium toxin injection had statistically significant impact on patients who showed low mean air flow rate during aerodynamic study. Conclusion:The botulinium toxin injection could reduce stuttering of patients with low mean air flow rate in aerodynamic study.

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2차 공기 주입방식에 따른 스토커형 소각로의 연소특성에 관한 수치해석적 연구 (A Numerical Study on the Combustion Characteristics for Stoker Type Incinerator with Various Injection Type of Secondary Air)

  • 정진;김창녕;조영민
    • 설비공학논문집
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    • 제15권10호
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    • pp.835-842
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    • 2003
  • A three dimensional numerical analysis has been conducted for a stoker type incinerator which has the capacity of 1.5 ton/hr. The objective of the present study is to predict the effects of swirl induced by secondary air and to find an optimal operating condition of the incinerator. In this study, combustion characteristics such as distributions of temperature, velocity and concentration of each species have been examined with various injection types of secondary air and with different flow rates of secondary air in the incinerator. It is found that the secondary air injection on the combustion process makes the path of fluid particle longer in the combustor and enhances the mixing between air and combustion gas by arousing a swirl. Therefore, the injection type of secondary air can be an important key in the design process of incinerator.

직분식 엔진에서 연료공급 조건에 따른 CNG와 공기의 혼합 및 연소특성 (Mixing and Combustion Characteristics of a CNG and Air according to Fuel Supply Conditions in a DI Engine)

  • 강정호;박종상;염정국;정성식;하종률
    • 한국분무공학회지
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    • 제13권1호
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    • pp.1-8
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    • 2008
  • It was investigated how fuel injection timing - early injection and later injection - in conjunction with throttle open rate effect the fuel-air mixing characteristics, Engine power, combustion stability and emission characteristics on a DI CNG spark Engine and control system that had been modified and designed according to the author's original idea. It was verified that the combustion characteristics were changed according to fuel injection timings and Engine conditions determined by different throttle open rates and rpm. It was found that the combustion characteristics greatly improved at the complete open throttle rate with an early injection timing and at the part throttle rate with a late injection timing. Combustion duration was governed by flame propagation duration in a late injection timing and by an early flame development duration in an early injection timing. As the result, we discovered that combustion duration is shortened, lean limit is improved, air-fuel mixing conditions controlled, and emissions reduced through control of fuel injection timing according to change of the throttle open rate.

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퍼지 제어 기법을 이용한 차량의 연료 제어 (Fuel Injection Control of Vehicles Using Fuzzy Control Technique)

  • 김광백;우영운;하상안
    • 한국정보통신학회논문지
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    • 제11권5호
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    • pp.1013-1018
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    • 2007
  • 자동차의 연료분사에 관여하는 전자제어 센서에는 공기유량 센서, 흡기온도 센서, 대기압 센서, 냉각수 온도센서, 스로틀 포지션 센서, 모터 포지션 센서 등이 있다. 본 논문에서는 흡기온도 센서의 온도 변화와 공기와 연료의 혼합비율인 공연비에 대해 퍼지 제어 기법을 적용하여 차량의 연료 소비를 제어하는 방법을 제안하였다. 제안된 기법에서는 각각의 공기 유입량과 연료 분사량을 이용하여 공연비 수치를 구한 후, 공연비, 흡기온도, 최종 연료 보정량에 대해 설정된 퍼지 소속 함수와 퍼지 추론 규칙에 따라 차량 연료가 제어된다. 제어하는 방법을 제시하였다. 시뮬레이션을 통한 일반적인 차량의 연료 제어 방법과 비교 분석한 결과, 제안된 방법이 차량의 연료제어에 있어 효과적임을 확인하였다.

스파크 점화기관에서 이차 공기 분사가 냉시동시 THC 배출량에 미치는 영향에 관한 실험적 연구 (Experimental Study of the Effect of Secondary Air Injection on the Cold Start Total Hydrocarbon Emissions in a Spark Ignition Engine)

  • 이승재;함윤영;전광민
    • 한국자동차공학회논문집
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    • 제11권1호
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    • pp.1-6
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    • 2003
  • Engine emission regulations are becoming more stringent nowadays. In cold transient regime, about 80% THC is exhausted to the atmosphere in the first 200s (US FTP cycles). Accordingly, reducing emission levels in the cold period immediately after the engine start before the catalysts reach their working temperature will be an especially critical factor in meeting more stringent regulations in the future. In this study, the total hydrocarbon quantities are measured using a Fast FID with gasoline fuel for a 4-cylinde. Sl engine, including Secondary Air Injection (SAI) system. Commercial SAI device's direction is reverse to the exhaust flow. In this study, a swirl flow type SAI system which is positioned between the exhaust manifold and exhaust port, was developed. We compared the swirl type secondary air injection with a commercial secondary air injection of .everse flow. The swirl type SAI showed better results in reducing HC by 26% than the commercial flow type SAI of reverse flow which was caused by the better mixing between the exhaust gas and the secondary air.