• Title/Summary/Keyword: Plug Valve

Search Result 36, Processing Time 0.024 seconds

Optimal Conditions of Co-Immobilized Mixed Culture System with Aspergillus awamori and Zymomonas mobilis (Aspergillus awamori와 Zymomonas mobilis로 구성된 혼합고정화 배양계의 최적 조건)

  • 박석규;이상원;손봉수;최수철;서권일;성낙계;김홍출
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.24 no.5
    • /
    • pp.803-810
    • /
    • 1995
  • Co-immobilized mixed culture system(A-Z system) composed of two different oxygen-demanding strains, aerobic(Aspergillus awamori) and anaerobic(Zymomonas mobilis) strains, in a Ca-alginate gel beads was developed to increase ethanol production from raw starch as a carbon source. Optimal mixture ratio of A. awamori and Z. mobilis was $1.25{\times}10^{9}\;spores/L-gel$ and 0.5g cells/L-gel, respectively. After 120 hours of cultivation, gel beads distinguished oxygen-rich surface for A. awamori from oxygen-deficient central part for Z. mobilis. At A-Z culture system, yield of ethanol on glucose, $Y_{p/s}=0.18$, was very low and there was high leakage of cells from surface of gel beads. At A-Z 36 cultrue system with changing silicon check valve for cotton plug at 36 hours in A-Z culture system, there was no cell leakage from gel beads, pH was maintained at around 4.3 during cultivation, and yield of ethanol on glucose, $Y_{p/s}=0.36$, showed 2 times higher than that of control culture system(cotton plug culture).

  • PDF

Effect of Value Timing on Residual Gas Fraction and Combustion Characteristics at Part Load Condition in an SI Engine (가솔린 엔진의 밸브타이밍 변화가 부분부하 조건에서 잔류가스량 및 연소특성에 미치는 영향)

  • 김철수;송해박;이종화;유재석;조한승
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.8 no.4
    • /
    • pp.26-33
    • /
    • 2000
  • In-cylinde flow and mixture formation are key contributors to both idle stability and combustion stability at part load condition in SI engine. The real time measurements of air-fuel ration and in- cylinder residual gas fraction are particularly important to obtain a better understanding of the mechanisms for combustion and emissions especially during cold start and throttle transient condition. This paper reports the cycle resolved measurements of residual gas fraction and equivalence ration near speak plug with value timing change and their effects on combustion characteristics at part load. The results showed that the effect of intake value opening on the residual gas fraction was smaller than that of exhaust valve closing because of the decreases of exhaust gas reverse flow from exhaust port. The variation of equivalence ratio near spark plug increased with the increase of value overlap and it closely related with heat release rate and combustion stability

  • PDF

A Study on Atomization Characteristics of Gasoline Impinging Spray Using Glow plug (글로우플러그를 이용한 충돌분무의 미립화특성에 관한 연구)

  • 문영호;오영택
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.5
    • /
    • pp.54-61
    • /
    • 2001
  • It is reported that during the cold starting, especially in gasoline engine, the engine response and the effect of HC emission can be improved by prompting atomization and reducing the quantity of fuel adhered to the range of injector tip, inlet port, and inlet valve. The purposes of this study are to promote atomization of fuel before air-fuel mixture in the inlet port. In order to achieve its goal, the glow plug is to evaluate the feasibility of for the early fuel evaporator and the spray behavior characteristics of gasoline, injected on the surface of glow plug with room temperature(2$0^{\circ}C$) and high temperature(25$0^{\circ}C$) is to examine. Particle motion analysis system(PMAS) was used to measure the SMD and the dropsize distribution of impinging spray and free spray. The results of this experiment, evaporation rate of impinging spray was higher than that of free spray, and the higher evaporation rate win, the smaller peak dropsize was. Especially, during early spray SMD of impinging spray was still smaller than that of fee spray.

  • PDF

Analysis of Spray and Flow Fields for Development of Spark-ignited Direct Injection Engine (가솔린 직분식 엔진의 연소실 개발을 위한 분무 및 유동장 해석)

  • Choi, K.H.;Park, J.H.;Lee, N.H.
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.6 no.6
    • /
    • pp.202-209
    • /
    • 1998
  • For development of SDI(Spark-ignited Direct Injection) engine, stratified mixture formation with adequate strength at spark plug was required in wide range of engine operating conditions. So, spray structure under high ambient pressure and spray distribution after impingement on piston bowl in motoring engine was visualized by using laser equipments. Also, incylinder bulk flow structure was measured by using PIV (Paiticle Image Velocimetry) system. Counter-rotating tumble port and bowl piston was found effective to conserve bulk motion directed to spark plug in compression stroke. In addition, mask attached near valve seat in intake port was proposed to attenuate conventional tumble component and enhance counter-rotating tumble component.

  • PDF

Effects of Port Masking on Part Load Performance: Part I - Lean Misfire Limit (포트 마스킹이 엔진의 부분부하 성능에 미치는 영향: Part I - 희박연소 한계)

  • 이원근;엄인용
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.5
    • /
    • pp.17-22
    • /
    • 2001
  • This paper is the first of companion papers, which investigate port-masking effects on lean misfire limit. Port-masking was applied to commercial SOHC 3-valve and DOHC 4-valve engine by inserting masking plates between manifold and port. To induce various conditions of stratification, six types of masking plates were applied. The masking plates were placed in the upstream of injector to prevent wall wetting and two ports were not separated to permit both fuel and air entering through masked port. The results were compared with those by conventional port throttling. The results show that lean misfire limit mainly depends on masking direction, that is, high lean misfire limit is achieved when the port near the spark plug is masked. The mechanism of stratification by masking is different from axial stratification by port throttling. In this case, the rich mixture entering through masked port plays a very important role in the stratification process.

  • PDF

Closure of patent ductus arteriosus with a vascular plug in a German Shepherd dog

  • Han-Joon Lee;Taehyung Kwon;Gyeonggook Park;Dong-Kwan Lee;Joong-Hyun Song;Kun-Ho Song
    • Korean Journal of Veterinary Service
    • /
    • v.47 no.1
    • /
    • pp.55-59
    • /
    • 2024
  • A 4-year-old, spayed female German Shepherd dog (GSD) weighing 22.4 kg was referred to Chungnam National University Veterinary Medicine Teaching Hospital with the chief complaint of a cardiac murmur. A continuous murmur was detected at the left basilar region upon auscultation. In the thoracic radiographs, slight bulging of the aorta, the main pulmonary artery, and the left atrium were observed. Echocardiography revealed continuous turbulent flow directed from the main pulmonary artery towards the pulmonary valve and consistently within the main pulmonary artery. Based on all the results, a diagnosis of type II A patent ductus arteriosus (PDA) was made, and plans were established to treat it with transcatheter occlusion. Transcatheter occlusion was performed using a vascular plug and successfully deployed at the PDA. The patient did not exhibit any complications. GSDs are relatively less common compared to small-breed dogs in South Korea. Considering that GSDs are predisposed to PDA, it is crucial to periodically assess the presence of PDA through auscultation and echocardiography, even in the absence of clinical signs. Transcatheter occlusion using a vascular plug can be an option for treatment and can yield favorable outcomes.

Study for Failure Examples Involved to Spark Plug Assembling Part Damage, Timing Maladjustment and Alien Substance Insertion in Intake Valve Part on LPG Vehicle Engine (자동차용 LPG 엔진의 점화플러그 장착 부 손상, 점화시기 조정불량, 흡입밸브 부 이물질유입 고장사례 연구)

  • Lee, IL Kwon;Kook, Chang Ho;Ham, Sung Hoon;Kim, Sung Mo;Hwang, Han Sub;Jung, Dong Hwa;Moon, Hak Hoon;Lee, Jeong Ho
    • Journal of the Korean Institute of Gas
    • /
    • v.25 no.2
    • /
    • pp.22-27
    • /
    • 2021
  • This paper is a purpose to study the failure examples for LPG vehicle. The first example, the researcher certified the incongruity phenomenon decreased engine power by ignition fire leakage because of spark plug threaded part damage assembling in cylinder head. The second example, the timing mark that accurately adjusting the camshaft and crankshaft position were twisted about 0.5 block each other. Finally, the researcher seeked the disharmony phenomenon as it couldn't set ignition timing. The third example, the researcher knew the failure phenomenon by interrupted the closing period for intake valve moving with air flow in the number 3 port of cylinder head as the foreign substance in cylinder head didn't remove. Therefore, the manager of a car has to thorough going inspect and the manufacture of a car must remove the cause of failure with quality assurance.

Lean Burn Characteristics in a Heavy Duty Liquid Phase LPG Injection SI Engine (대형 액상분사식 LPG 엔진의 희박연소특성에 관한 연구)

  • O, Seung-Muk;Kim, Chang-Eop;Lee, Jin-Uk;Kim, Chang-Gi;Gang, Geon-Yong;Bae, Chung-Sik
    • 연구논문집
    • /
    • s.33
    • /
    • pp.5-16
    • /
    • 2003
  • Fuel distribution, combustion, and flame propagation characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine. Optically accessible single cylinder engine and laser diagnostics system were built for quantifying fuel concentration by acetone PLIF(planar laser induced fluorescence) measurements. In case of Otto cycle engine with large bore size, the engine knock and thermal stress of exhaust manifold are so critical that lean burn operation is needed to reduce the problems. It is generally known that fuel stratification is one of the key technologies to extend the lean misfire limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs2.3. Thus, strong swirl flow could promote desirable axial fuel stratification and, in result, may make flame propagation stable in the early stage of combustion.

  • PDF

A Study on Mixture Composition and Combustion Characteristics in Gasoline Engine (가솔린 기관의 혼합기 조성과 연소 특성에 관한 연구)

  • Kim, Gi-Bok;Yoon, Chang-Sik
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.18 no.4
    • /
    • pp.197-206
    • /
    • 2015
  • Recently the automobile engine has been developed in achieving the high performance, fuel economy, and emission reduction. In a conventional spark ignition engine the fuel and air are mixed together in the intake system, inducted through the intake valve into the cylinder, and then compressed. Under normal operating conditions, the combustion is initiated towards the end of the compression stroke at the spark plug by an electric discharge. Following inflammation, a flame develops and propagates through this premixed fuel-air mixture. Therefore the state of mixture is very important in the combustion and emission characteristics. In this study the combustion and emission characteristics were tested and analyzed with changing the mixture composition and engine operating parameters in order to improve the combustion and performance in engine.