• Title/Summary/Keyword: Valve Opening Characteristics

Search Result 175, Processing Time 0.039 seconds

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

Analysis of the Driving Performance in Piezo Injector for Clean Diesel Engine (친환경 디젤엔진용 차세대 피에조 인젝터의 구동성능 해석)

  • Lee, Jin-Wook;Kang, Kern-Yong;Min, Kyoung-Doug
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • 2006.06a
    • /
    • pp.33-34
    • /
    • 2006
  • In this study, a prototype piezo-driven Injector. as a new method driven by piezoelectric energy, has been designed and fabricated based on the concept of inverse piezo-electric effect to overcome the major drawbacks of conventional solenoid-driven injector with a fixed and slow control of injection rate. The effects of an electric control between the solenoid valve and piezo-ceramic stack for injector needle's driving on the dynamic characteristics were usually investigated. We found that this piezo-electric actuator has the main advantage to drastically reducing the time of injector nozzle opening, as well to exert higher force output levels.

  • PDF

Pressure Variations in Intake and Exhaust Manifold of a Single Cylinder Engine (단기통 엔진의 흡.배기계의 압력 변동에 관한 연구)

  • Choi, Seuk-Cheun;Lee, Young-Hun;Lee, Sang-Chul;Chung, Han-Shik;Lee, Kwang-Young;Jeong, Hyo-Min
    • Proceedings of the KSME Conference
    • /
    • 2003.11a
    • /
    • pp.775-780
    • /
    • 2003
  • In this study, a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold in a single cylinder engine. To get the boundary conditions for a numerical analysis, one dimensional and unsteady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the exhaust pipe diameters to calculate the pulsating flow when the intake and exhaust valves are working. As the results of numerical analysis, the shapes and distributions of the exhaust pipe pressures were influenced strongly on the cylinder pressure. As the exhaust pipe diameter is decreased, the amplitude of exhaust pressure is large and the cylinder pressure was showed low in the region of intake valve opening time.

  • PDF

Analysis of Transient Characteristics for Turbopump-fed Liquid Propellant Rocekt Engine in Start-up (터보펌프식 액체 로켓 엔진의 시동 과도 특성 해석)

  • Son, Min;Kim, Duk-Hyun;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.05a
    • /
    • pp.34-37
    • /
    • 2010
  • One dimensional transient analysis was studied for turbopump-fed liquid propellant rocket engine(LRE) system in starting using AMESim. The effects of timing of gas generator fuel valve opening and gas generator ignition to start-up stability were researched for open cycle type system using LOX/RP-1 to propellants. Result show that the parameters and sequence on start-up should be considered to design optimized turbopump-fed LRE system.

  • PDF

A Study on Flow Distribution to Flocculation Basins Using DOE and RSA (실험계획법과 반응표면분석법을 적용한 응집지로의 유량분배에 관한 연구)

  • Kim, Seong-Jae;Kyung, Gyu-Sun;Jeong, Heui-Jung;Kim, Hyeong-Seop;Yang, Sa-Sun
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.35 no.12
    • /
    • pp.918-928
    • /
    • 2013
  • The inequitable flow distribution to flocculation basins is an important problem faced in many water treatment plants. This is caused by the structure of a distribution channel, the height differences of outlet weirs etc. But, a modified approach for the structures has no effectiveness to achieve flow equality. The aim of this study is to reduce the inequality by adopting optimized inlet valve opening (%) of the flocculation basins using DOE (Design of Experiments) and RSA (Response Surface Analysis). The inlet valve openings (%) and inflow distributions (%) of 6 paralleled basins were set as factors (X) and characteristics(Y) respectively. 2 level factorial experiments and RSA were conducted for optimization and regression analysis (Y = f(X) + Const.). Adopting the optimized inlet valve opening (%) at field, standard deviation of flow distribution (%) and effluent turbidity was declined from 3.80% to 0.42% and from 0.29 NTU to 0.03 NTU respectively.

Behaviour of Nak-dong River Sand on Cyclic Stress History (낙동강 모래의 반복응력이력에 의한 거동)

  • 김영수;박명렬;김병탁;이상복
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.11a
    • /
    • pp.295-302
    • /
    • 2000
  • Earthquakes not only produce additional load on the structures and underlying soil, but also change the strength characteristics of the soil. Therefore, in order to analyze soil structures for stability, the behaviour after earthquake must be considered. In this paper, a series of cyclic triaxial tests and monotonic triaxial tests were carried out to investigate the undrained shear strength and liquefaction strength characteristics of Nak-Dong River sand soils which were subjected to cyclic loading. The sample was consolidated in the first stage and then subjected to stress controlled cyclic loading with 0.1Hz. After the cyclic loading, the cyclic-induced excess pore water pressure was dissipated by opening the drainage valve and the sample was reconsolidated to the initial effective mean principal stress(p/sub c/'). After reconsolidation, the monotonic loading or cyclic loading were applied to the specimen. In the results, the undrained shear strength and liquefaction strength characteristics depended on the pore pressure ratio(Ur=U/p/sub c/'). The volume change following reconsolidation can be a function of cyclic-induced excess pore water pressure and the maximum double amplitude of axial strain.

  • PDF

Improved Design in Fishing Operation System for Small Inshore and Coastal Fishing Vessels-I -Design of a Automatic Winch System- (소형 연근해 어선의 조업 시스템 개선에 관한 연구-I -자동 권양 윈치 시스템의 설계-)

  • 이대재
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.36 no.1
    • /
    • pp.12-24
    • /
    • 2000
  • The electro-hydraulic servo winch system built in a automatic tension control equipment was designed with a latent need for an advanced system in fishing operations of the inshore and coastal fishing vessels. In order to keep the constant tension condition of warp under loading, a tension control circuit was added to the servo winch system.The dynamic performance in the open loop behaviour of the designed winch system was investigated and its applicability was tested for various possibilities of load using a load generator especially developed in order to this study.The mechanical characteristics of this system is different from that of a conventional type, that is, the tension, length, line speed and drum revolution can be automatically controlled by the information from various sensors, such as torque, rpm and pressure transducers. from the experiment results, it was verified that the servo winch system has very good output and tracking behaviour for the control input signals in different operating conditions though overshoot of out 8% in the transient characteristics of torque under the load though a overshoot of about 8% in the transient characteristics of torque under the load condition can be observed when the opening of servo valve, adjustable by the input voltage between - 10 V up to 10 V, changed suddenly.Consequently, the improved fishing winch system can be effectively used as the automatic shooting and hauling equipment of low cost for small inshore and coastal fishing vessels which engage in net fishing.

  • PDF

Exhaust Emissions Characteristics on the SI Engine according to the Air-Fuel Mixture with Ozone (혼합기 오존 첨가에 따른 SI기관의 배기배출물 특성)

  • Lee, B.H.;Yi, C.S.;Lee, Y.H.;Lee, C.K.;Jeong, H.M.;Chung, H.S.
    • Journal of Power System Engineering
    • /
    • v.10 no.3
    • /
    • pp.5-10
    • /
    • 2006
  • In a conventional and lean operating engine, the state of mixture is very important in the combustion and emission characteristics. Lean operation is known to decrease the formation while maintaining a good fuel economy, but the unstable operation due to misfire and erratic combustion prevents engines from being operated at very lean mixtures, so both combustion rates and exhaust emission formation need to be satisfied comparably. In this study, it is designed and experimented the modified engine, and analyzed the combustion and exhaust emission according to the change of engine speed and with adding ozone. The conclusions were drawn out and enumerated as follows. 1. At the experimental result of automobile diesel engine, it has been verified that the formation of particulate matter(PM) gas is able to be lower with the addition of optimum quantities of ozone. 2. Carbon monoxide(CO) was formed by the lack of oxygen and the thermal dissociation in the combustion process. Therefore, with the change of swirl valve's position and addition of oxygen and ozone, CO formation was decreased by the increasing of excessive O2, but it was increased by the temperature of combustion gas growing higher. As a result of the two effects, CO formation was decreased in this study. 3. Hydrocarbon(HC) was formed by the lack of O2, and the flow of mixture in cylinder. According to opening of the swirl valve and adding the oxygen and ozone, hydrocarbon gas was decreased by 20%, 9%, and 27.5%, respectively. 4. Nitric oxides($NO_x$) was strongly affected by the combustion gas temperature. As a result of respectively experimental conditions, $NO_x$ formation was increased about 20% due to (be the) high(er) combustion gas temperature.

  • PDF

Flow Visualization of Arteriovenous Grafting Using PIV Technique (PIV 기법을 이용한 동정맥루 문합에 대한 유동가시화)

  • Jeon, Min-Gyu;Kim, Hyoung-Ho;Suh, Sang-Ho;Choi, Young Ho;Lee, Hyun-Jin;Doh, Deog-Hee
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.37 no.11
    • /
    • pp.985-990
    • /
    • 2013
  • An arteriovenous fistula is artificially produced using a graft for hemodialysis in patients. In an arteriovenous graft (AVG), the angle of its arterial or venous anastomosis play an important role in producing flows inside blood vessels, through which a stenosis may occur. Most studies thus far have focused on CFD results. In this study, a PIV technique is used to analyze the hemodynamic characteristics at the arterial or venous anastomosis of an AVG having an angle of $30^{\circ}C$. For flow dynamic similarity, the Reynolds number is set to be the same for real and simulated flows. A PIV experiment is performed with a control valve in the arterial part. In conclusion, the recirculation flow appeared in the bifurcation area and the total blood velocity changed according to the extent of valve opening.

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