• 제목/요약/키워드: Engine valve train

검색결과 43건 처리시간 0.023초

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

  • 김도중;정영종;이중희
    • 한국자동차공학회논문집
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    • 제12권6호
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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.

엔진내구시험을 통한 Valve Train 수명예측에 관한 연구 (2) (A Study of Valve-train Life Time Estimate in Engine Durability Test (2))

  • 김재진;이환희;명광희;민병두
    • 한국자동차공학회논문집
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    • 제22권3호
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    • pp.75-80
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    • 2014
  • In previous study, make an attempt to estimate exhaust valve seat and seat-ring wear acceleration factor for engine durability test with measuring and consideration of wear mechanism. But found abnormal initial wear rate in exhaust valve seat-ring. And have to improve exhaust valve seat-ring wear rate for reliability reason, because next GDI/Turbo engine is based on this engine and GDI/Turbo engine have higher combustion pressure and higher thermal load. In this study, Trying to find the cause of abnormal wear factor, improve valve-train durability by change specification & design of parts and verify variant parts for improving durability of valve-train. And then I would like to propose a design guide line of valve-train system in a reliability point of view, besides make a complement of previous study.

가솔린기관의 밸브트레인 마찰특성 (A Study on the Friction Force Onaracteristics of Valve Train System in Gasoline Engine)

  • 윤정의;이만희;김재석
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제28회 추계학술대회
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    • pp.30-37
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    • 1998
  • It is well known that reduction of friction loss due to the valve train system greatly affects on improvement of fuel economy in internal combustion engine. In order to investigate friction characteristics of valve train system we carried out friction force measurement using test rig developed by ourselves. From test results, we concluded that characteristics of lubrication and friction torque on the valve train system such as mixed and hydrodynamic was mainly governed the contact type between cam and tappet.

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An Analysis of Valve Train Behavior Considering Stiffness Effects

  • Chun, Dong-Joon;Lee, Jin-Kab
    • Journal of Mechanical Science and Technology
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    • 제14권3호
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    • pp.283-290
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    • 2000
  • To maintain the specific volumetric efficiency of a heavy-duty diesel engine, an understanding of the behavior of each part of the valve train system is very important. The stiffness of the valve train system has a strong influence on the behavior of the valve train than valve clearance, heatresistance, or the durability of parts. In this study, a geometrical cam design profile using a finite element model of the valve train system is suggested. The results of the valve behavior according to the change in stiffness is analyzed for further tuning of the valve train system.

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가솔린기관의 밸브트레인 시스템 마찰력측정 시스템개발 (Development of Valve Train Friction Force Measuring System in Gasoline Engine)

  • 윤정의;이만희;김재석
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제28회 추계학술대회
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    • pp.75-81
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    • 1998
  • It is very important to evaluate the friction force of valve train system in the aspect of reducing friction loss of engine. To this end, we have developed measuring system of friction force of engine valve train system. There were two major factors in the process of development of it. One was it had to accurately measure the friction force up to 3500 Crpm without any problems such as mechanical vibration, electrical noise and so on. The other was it also had to simulate real engine conditions such as Crpm, oil temperature, oil pressure and oil aeration including effect of belt drive system. In this paper we have introduced the process of development of it based on test results, and also analysis process of measured data.

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내연기관 밸브 트레인 동역학의 수치해석 (Numerical Analysis for Valve Train Dynamics of an Internal Combustion Engine)

  • 이기수;김동우
    • 한국자동차공학회논문집
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    • 제11권2호
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    • pp.31-39
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    • 2003
  • Numerical analysis for valve train dynamics of an internal combustion engine is presented. The components of the valve train are modeled by finite element techniques, and the dynamic contacts between the components are analyzed by the solution strategies of differential algebraic equations. Also an iterative scheme similar to the augmented Lagrange multiplier method is employed to enforce the contact constraints. It is shown that the contact and separation between the components of the valve train can be computed by the finite element techniques, and the numerical examples are presented to demonstrate the efficiency of the solution.

폴리다인 캠 밸브 트레인의 동적 특성에 관한 연구 (A Study on the Dynamic Characteristics of Polydyne cam Valve Train)

  • 유환신;천동준
    • 한국항행학회논문지
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    • 제15권3호
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    • pp.441-448
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    • 2011
  • 엔진 밸브 트레인 계는 다수의 밸브 부품 시스템으로 구성되어 있어서 동적 특성을 나타내는 방정식을 세우고 그 거동을 정확히 정의 및 제시하는 것이 매우 중요하다. 엔진 작동 상태에서 밸브 트레인 시스템이 이상적으로 작동하기 위해서는 밸브의 간극 유지, 부품의 내열성 및 내마모성 등도 많은 영향을 끼치지만 기본적으로 캠 형상이 밸브 트레인 계의 동적 거동 특성에 미치는 영향이 매우 크다. 기본적으로 캠 거동 곡선을 표현하기 위해서는 폴리노미얼 캠, 멀티폴 캠 또는 폴리다인 캠 곡선을 사용하는데, 본 연구에서는 고속으로 작동하는 엔진의 동적 특성을 가장 잘 표현하는 폴리다인 캠 프로파일 방정식을 이용하여 기하학적인 모델링과 수학적 해석을 전개하여 각 변수가 밸브 거동에 미치는 영향을 제시하였다.

Ceramic 재질을 이용한 자동차용 대형 디젤 엔진 Valve Lifter 연구 I. Brazing Process에 의한 Ceramic-Metal 접합체 개발 (Studies of Valve Lifter for Automotive Heavy Duty Diesel Engine by Ceramic Materials I. Developmet of Ceramic-Metal Joint by Brazing Method)

  • 윤호욱;한인섭;임연수;정윤중
    • 한국세라믹학회지
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    • 제35권2호
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    • pp.163-171
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    • 1998
  • Continuously contacting with camshaft the face of Valve Lifter made of cast iron brings about abnormal wear such as unfairwear or earlywear because it is heavily loaded in the valve train systems as the engine gets more powered. This abnormal wear becomes a defet namely over-clearance when the valve is lifting so that the fuel gas imperfectly combusted by unsuitable open or close aaction of the engine valve in the combustion chamber. The imperfect combustion in the end results in the major cause of air pollution and combustion chamber. The imperfectly combusted by unsuitable open or close action of the engine valve in the combustion chamber. The imperfect combustion in the end results in the major causes of air pollution and decrease of the engine output. Consequently to prevent this wear this study was to develop the valve lifter which is joined by brazing process with SCM435H and a tip by manufacturing the face as a superhardened which is joined by brazing process with SCM435H and a tip by manufacturing the face as a superhardened ceramics alloy which has high wear resistance. Having the excellent surface hardness with Hv1100-1200 the sintered body developed with superhardened alloy(WC) can endure the severe face loading in the valve train system. We experienced with various brazing alloys and obtained the excellent joining strength to the joint had 150MPa shear strength. Interface analysis and microstructure in a joint were examined through SEM & EDS Optical microscope. Also 2,500 hours high speed(3,000-4,000 rpm) and continuous (1step 12hr) engine dynamo testing was carried out to casting valve liter and ceramics-metal joint valve lifter so that the abnormal wears were compared and evaluated.

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LOW FUEL CONSUMPTION AND LOW EMISSIONS - ELECTROMECHANICAL VALVE TRAIN IN VEHICLE OPERATION

  • Pischinger, M.;Salber, W.;Staay, F.V.D.;Baumgarten, H.;Kemper, H.
    • International Journal of Automotive Technology
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    • 제1권1호
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    • pp.17-25
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    • 2000
  • The electromechanical valve train (EMV) technology allows for a reduction in fuel consumption while operating under a stoichiometric air-fuel-ratio and preserves the ability to use conventional exhaust gas aftertreatment technology with a 3-way-catalyst. Compared with an engine with a camshaft-driven valve train, the variable valve timing concept makes possible an additional optimization of cold start, warm-up and transient operation. In contrast with the conventionally throttled engine, optimized control of load and in-cylinder gas movement can be used for each individual cylinder and engine cycle. A load control strategy using a "Late Intake Valve Open" (LIO) provides a reduction in start-up HC emissions of approximately 60%. Due to reduced wall-wetting, the LIO control strategy improves the transition from start to idle. "Late Exhaust Valve Open" (LEO) timing during the exhaust stroke leads to exhaust gas afterburning and, thereby, results in high exhaust gas temperatures and low HC emissions. Vehicle investigations have demonstrated an improved accuracy of the air-fuel-ratio during transient operation. Results in the New European Driving Cycle have confirmed a reduction in fuel consumption of more than 15% while meeting EURO IV emission limits.

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오일 등급에 따른 트라이볼로지 특성의 관한 실험적 고찰 (Experimental Study of Tribological Properties According to Oil Grade)

  • 이종호;서국진;황윤후;한재호;김대은
    • Tribology and Lubricants
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    • 제37권6호
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    • pp.246-252
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    • 2021
  • Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.