• Title/Summary/Keyword: Engine valve

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An Experimental Study on the Effect of Valve Train Design Parameters on the Diesel Engine Valve Rotation (디젤엔진의 밸브회전에 미치는 밸브트레인 설계변수들의 영향에 관한 실험적 연구)

  • Kim, Do-Joong;Jeong, Young-Jong;Lee, Jung-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.1-8
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    • 2004
  • In this paper we present the effects that valve train design parameters and operating conditions have on the valve rotation properties of a diesel engine. Rotation of intake and exhaust valves are very closely related to the long term durability of diesel engines. of the valves do not rotate even at a rated engine speed, it causes the uneven wear of the valve seat and valve head contact area, which eventually shortens the engine life. Because the rated speed of a diesel engine is relatively lower than that of a gasoline engine, the operating condition of a diesel engine produces tough environment for valve rotation. Therefore, the valve rotation is an important problem which should be solved in the early stage of engine development. In this study, we developed a new technique to measure the valve rotation and shaking motion simultaneously using three proximity sensors. Valve train rotating properties of a diesel engine were measured under various engine operating conditions.

Predicting Technique of the Performance for a Five-Valve Gasoline Engine by Gas Exchange Simulation (가스 교환 시뮬레이션에 의한 5 밸브 가솔린 엔진의 성능 예측 기술)

  • 성백규;이기형
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.1
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    • pp.51-58
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    • 2002
  • A simulation model has been developed to predict the performance of 5-valve gasoline engine by gas exchange process with combustion model. In this study, we simulated the intake flow characteristics and performance of 5-valve engine with entwine speed and we compared the 5-valve engine performance with that of 4-valve engine. As a result. the calculated value was in consistency with the measured value relatively. The performance of 5-valve engine was higher than that of 4-valve engine in high engine speed region.

A Study on Exhaust Gas Characteristics and Engine Performance of EGR Valve Installed Engine for Development of EGR Valve Test System (EGR 밸브 평가 장치 개발을 위한 EGR 장착 엔진 성능 및 배출 가스 특성 연구)

  • Na, D.H.;Ko, C.S.;Seo, H.J.;Lee, C.E.
    • Journal of Drive and Control
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    • v.9 no.4
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    • pp.52-57
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    • 2012
  • In this study, in order to understand contents and ranges of design for the EGR Valve test system for improving quality and performance of EGR Valve, engine performance and exhaust gas characteristic of 3L-class diesel engine was analyzed. Experimental operation of engine performance test was performed with 50% engine load and 20% and 100% opening ratio of EGR Valve. From test of performance and exhaust gas characteristic of engine, torque output of engine and temperature and pressure of inlet and outlet of EGR Valve were measured. As a result, for design of EGR Valve test system, input fluid flow of EGR Valve must be set the same amount with exhaust gas flow that was below of engine speed of 2,500 rpm, and temperature of inlet of EGR Valve must be set under about $510^{\circ}C$. And the difference of temperature between inlet and outlet of EGR Valve must be over than about $200^{\circ}C$. Exhaust gas of inlet and outlet of EGR Valve were under 1 bar that was not considerable, and the difference of pressure between inlet and outlet of EGR Valve were under 1 bar that could not effect on mechanical operation of EGR Valve.

A Study on the Effect of Valve Timing on the Performance and Idle characteristics of 3-Cylinder LPG Engine (밸브 타이밍 변화가 3기통 LPG 엔진의 성능과 Idle 특성에 미치는 영향에 관한 연구)

  • 이지근;이한풍;노병준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.3
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    • pp.27-34
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    • 1997
  • The effects of the intake and exhaust valve timing to improve the engine performance in a spark ignition 3-cylinder LPG engine with a closed loop fuel supply system were studied. The engine torque and power have been measured using the 75kW EC-dynamometer while adjusting the optimal fuel consumption ratio with a solen- oid driver. As the results from this experiment, when intake valve opening is $12^{\circ}$ BTDC, intake valve closing is $36^{\circ}$ ABDC, exhaust valve opening is $12^{\circ}$ ATDC, and exhaust valve closing is $36^{\circ}$ BBDC respectively, the best torque characteristics in low and high speeds for a gives engine were obtained. And also we could find that the torque characteristics in low speeds were affected by the timing of exhaust valve open. An increased valve overlap by the EVC delay was ineffectual to the torque characte- ristics improvement in high speeds.

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A Study on the Characteristics of Gasoline Engine Performance Equipped with Perforated Throttle Valve (다공 스로틀밸브 장착 가솔린기관의 성능 특성에 관한 연구)

  • Cho, B.O.;Lee, C.S.
    • Journal of ILASS-Korea
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    • v.1 no.2
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    • pp.50-56
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    • 1996
  • In an fuel injection type gasoline engine, atomization of fuel droplet and mixture formation process are very important to understand engine combustion efficiency, and also has influence directly on the decision of engine performance and pollutant emission. In this study, perforated throttle valve instead of solid type throttle valve was developed and equipped to an SPI engine to promote secondary atomization and good droplet-air mixture formation. From the engine performance lest. it was verified that the case of perforated valve kas more advantages in each experimental parameters such as in cylinder gas pressure, mass burnt ratio, fuel consumption rate, and pollutant emission characteristics than that of solid one equipped. No matter what the same perforated valve, there are some distinct results in engine performance characteristics according to the perforate ratio.

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Intake Valve Temperature Effect on the Mixture Preparation in a SI Engine During Warm-up

  • 신영기
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.5
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    • pp.51-66
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    • 1997
  • A heat transfer model of the intake valve in a spark ignition engine is presented, which is calibrated with a number of the valve temperature profiles measured during engine warm-up for the gaseous fuel(propane). The valve is divided into four identical elements for which the assumption of lumped thermal mass is applied. The calibration is made so that the difference between the measued and simulated valve temperatures becomes minimal. Then the model is applied to the cases of the liquid fuel(indolene) to estimate the amount of the liquid fuel vaporized from the intake valve by assuming that fuel evaporation accounts for the deficit of the heat balance budget. The results of the model show quantitative contribution of each heat transfer source to the heat balance. The behavior of the calculated mass fraction of the fuel vaporized from the intake valve explains how the liquid fuel evaporate during engine warm-up. The mass fraction at warmed-up condition is closely related with the fraction directly targeted on the valve back by the fuel spray geometry.

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A Study on the Steady Intake Flow Characteristics of the Intake 3-Valve Cylinder Head (흡기3밸브 실린더 헤드의 흡입 정상유동 특성에 관한 연구)

  • Chung, Jae-Woo;Lee, Ki-Hyung;Kim, Woo-Tae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.6
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    • pp.880-885
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    • 2000
  • Flow patterns and steady flow characteristics of an intake 3valve cylinder head are not obviously declared. Thus, in the study, the characteristics and limitation of intake flow coefficient which applied to multi intake valve engine are introduced. The flow coefficient and tumble characteristics are investigated by means of the steady flow test and flow visualization method. As the results, it is found that the intake flow rate is dominated by effective valve open area. In addition, this paper shows that the mass flow rate of intake 3valve engine is greater than that of intake 2valve engine and tumble flow of intake 3valve engine is superior to that of intake 2valve engine.

THEORETICAL FLOW ANALYSIS AND EXPERIMENTAL STUDY ON TIME RESOLVED THC FORMATION WITH RESIDUAL GAS IN A DUAL CVVT ENGINE

  • Myung, C.L.;Kwak, H.;Hwang, I.G.;Park, S.
    • International Journal of Automotive Technology
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    • v.8 no.6
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    • pp.697-704
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    • 2007
  • Recently, a variable valve timing system has been widely adopted in internal combustion engine in order to improve the fuel economy and torque at low engine speed. In addition, it is known that varying valve timing according to the various engine operations could reduce exhaust gas, especially NOx, because of residual gas by valve overlap. In this study, to improve the low exhaust gas and fuel economy at part load condition, the residual gas and back flow of exhaust gas due to valve overlap were calculated computationally. Moreover, the characteristics of engine performances and NOx formations were investigated with the experiment of combination of intake and exhaust valve timing condition. Under these various valve operating conditions, the effects of both the positive valve overlap and negative valve overlap(valve underlap) were examined simultaneously. Finally, the characteristics of cyclic THC emission were analyzed by using Fast Response FID(FR-FID) in the cylinder, intake port and exhaust port positions. Besides, the effect of the different gradients of the valve timing change on engine performance was investigated and an optimum control strategy was suggested.

Design and implementation of a throttle valve controller for engine dynamometer systems using fuzzy logic (퍼지논리를 사용한 엔진 동력계 시스템의 트로틀 밸브 제어기 설계 및 구현)

  • Shin, Wee-Jae;Lee, Sang-Yun
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.6
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    • pp.588-593
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    • 1997
  • This paper shows a design and implementation of throttle valve controller for engine dynamometer system using fuzzy logic. Recently, we demanded the excellent measuring equipment so as to improve engine performance. The throttle valve control for engine dynamometer system is a very particular part in the engine control. Since the structure of engine dynamometer system is very complicated and has nonlinear elements which are influenced by disturbance of vibration, heating, cooling, and energy loss so on. In this paper, fuzzy logic control application have been successful in throttle valve control problem for engine dynamometer system in which the conventional control had difficulties dealing with the system. In this study, we propose a method that the control strategy uses Fuzzy Look-up table and normalization and obtained the satisfying result from realized throttle valve controller for engine dynamometer system.

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An experimental study on valve lash diagnosis using cylinder head vibration signal (실린더 헤드에서의 진동신호를 이용한 밸브간극 진단에 관한 실험적 연구)

  • 석정호;김원진;박윤식
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.5
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    • pp.117-127
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    • 1992
  • In this work, the possibility to diagnose valve lashes of an automotive diesel engine via cylinder head vibration/noise analysis is studied. First of all the measurement signals and conditions are selected after considering which signals and conditions are most suitable to diagonse valve lashes. Both accelerometer and microphone are used to measure cylinder head accelerations and acoustic pressure due to valve impact on cylinder head. The signals are measured in both cranking and engine firing conditions. Finally, it was found that acceleration signal obtained in engine operating condition is the most reliable signal to diagnose the valve lash condition. The valve closing angle and the peak acceleration due to valve close are chosen to analyze the valve lash condition. The measured cylinder head acceleration signals are statistically tested to derive information which are useful to judge the valve lash. In conclusion, it was found that the developed technique can be one of feasible methods to diagnose the valve conditions while the engine is in operation.

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