• Title/Summary/Keyword: Cylinder pressure

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The pulsating pressure in the intake and exhaust manifold of a single cylinder engine by the various of engine revolutions

  • Chung, Han-Shik;Choi, Seuk-Cheun;Jong, Hyo-Min;Lee, Chi-Woo;Kim, Chi-Won
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.1
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    • pp.75-82
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    • 2004
  • In this research, a computer analysis has been developed for predicting the Pipe pressure of the intake and exhaust manifold in a small 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 Characteristics). The main numerical parameters are engine revolutions. to calculate the Pulsating flow which the intake and exhaust valves are working. The distributions of the exhaust pipe pressures were influenced strongly to the cylinder pressures and the shapes of exhaust pressure variation were similar to the Inside of cylinder pressure As the engine revolutions are increased. the intake pressure was lower than ambient pressure. The amplitude of exhaust pressure had increased and the phase of cylinder pressure $P_c$ is delayed and the amplitude of cylinder pressure were increased.

Analysis of Cylinder Compression Pressure Uniformity and Valve Timing by Start Motor Current and Cylinder Pressure during Cranking (기동 모터의 전류 파형과 실린더 압력 분석을 통한 기관의 압축 압력 균일도 및 밸브 개폐 시점 이상 여부 분석)

  • Kim, In-Tae;Park, Kyoung-Suk;Shim, Beom-Joo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.1
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    • pp.133-138
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    • 2011
  • Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Therefore, uniformity of compression pressure and valve timing became one of most important engine design and production standard. Conventional method to evaluate compression pressure uniformity is to measure each cylinder pressure by mechanical pressure gage during cranking. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and also causes high manhour and cost. To check valve timing, related FEAD parts should be disassembled and timing mark should be checked manually. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. With this new methodology, possibility to detect leaky cylinder and wrong valve timing was observed.

A Study on Design of Decatizing Cylinder with an Uniformly Distributed Pressure using Finite Element Method (유한요소법을 이용한 균압 구조를 가진 Decatzing Cylinder 설계에 관한 연구)

  • Kim, Jong-Su;Yun, Ho-Eop
    • 연구논문집
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    • s.32
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    • pp.111-120
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    • 2002
  • In this paper, the design of a decatizing cylinder with uniformly distributed pressure in a decatizing system is investigated by using the Finite Element Method. Particularly, since deflection of a cylinder will not perform to iron the fabrics, the cylinder design insuring uniform pressure is very important. In this paper proposed two improved cylinder model obtained by changing the support type of the bean and the support location. And perform optimization with two improved cylinder model.

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Numerical Study on the Stress Safety of a Cylinder for an Injection Molding Machine (사출성형기용 실린더의 응력안전성에 관한 수치적 연구)

  • Kim, Chung-Kyun;Kim, Kyung-Seob
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.4
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    • pp.401-406
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    • 2011
  • This study presents the stress safety analysis of a cylinder, which is manufactured by a tempered ASTM D2, tempered SM45C and normalized SM45C materials, respectively. The inner diameter of three cylinder models are 85mm, 95mm, and 11 Omm and the total length of a cylinder is 2,365mm for a high pressure injection molding machine. The FEM computed results show that the inner diameter of 85mm with a thick thickness of 62.5mm may produce the injection pressure of 325MPa and the inner diameter of 110mm with 50mm thickness reduces up to the injection pressure of 220MPa because of a reduced thickness of a cylinder. These injection pressures are enough for a high pressure injection molding machine assembled by ASTM D2 cylinder. And also, an injection cylinder manufactured by a tempered SM45C material in which is low priee may produce 225MPa injection molding pressure and this may sufficiently endure stress safety compared to that of ASTM D2 cylinder material. Thus, this study recommends that tempered SM45C cylinder is appropriated for a mild injection molding machine as an alternative cylinder material when the safety strength and low prices are considered. But the normalized SM45C cylinder material does not meet a stress safety of yield strength in general.

Development of Pressure Observer to Measure Cylinder Length of Harbor-Construction Robot (항만공사용 로봇의 실린더 길이 측정을 위한 압력 옵서버 개발)

  • Kim, Chi-Hyo;Park, Kun-Woo;Kim, Tae-Sung;Lee, Min-Ki
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.3
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    • pp.299-308
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    • 2011
  • In this study, we develop a pressure observer to measure the cylinder length of a harbor-construction robot. For the robot control, sensors are required to measure the length of a hydraulic cylinder. The cylinder-position sensor is relatively expensive when the operating environment prohibits external approaches for the measurement of the cylinder position. LVDT or linear scales are usually mounted on the outside of the cylinder, which causes poor durability on a construction site. We use a pressure sensor to indirectly estimate the length of the cylinder. The pressure sensor is mounted inside a hydraulic valve box so that it is protected by the box and easy to waterproof for an underwater robot. By treating oil as a compressible fluid, we derive the nonlinear pressure dynamics as a function of the cylinder position, velocity, and pressure. The recursive least squares (RLS) algorithm is applied to identify the dynamic parameters, and the pressure observer estimates the cylinder position through the pressure acting on the head and the rod of the hydraulic cylinder. The position accuracy is relatively low, but it is acceptable for a construction robot that handles large armor stones.

Hydrodynamic pressure distribution between a piston and cylinder - Experiment (1) (피스톤과 실린더 사이에서의 압력분포-실험(1))

  • 김영환;박태조
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.304-309
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    • 2001
  • In this paper, the hydraulic oil pressure distributions are measured in the clearance gap between a stationary piston and moving cylinder apparatus. The results showed that the hydrodynamic pressure distributions are highly affected by the speed of cylinder and further experimental and analytical studies are required to obtain more accurate results. Therefore present experimental method can be used to enhance the performance of various hydraulic components adopting the piston-cylinder mechanism.

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Numerical Analysis of Pressure Distribution in Piston-Cylinder Unit for Accurate Pressure Measurement (유압측정을 위한 피스톤-실린더 간격내의 압력분포에 대한 수치해석)

  • U, Sam-Yong;Park, Jong-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.9
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    • pp.2909-2915
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    • 1996
  • Precise and accurate pressure measurements are obtained using deadweight piston gauges. Pressure distribution and elastic distortion in the piston-cylinder unit are the leading factors in determination of effective area. The distortion depends upon the pressure distribution in the clearance between piston and cylinder and those are coupled each other. Considering the viscosity pressure relation of oil and governing flow equation in the clearance, a new numerical iterative algorithm is developed. The disagreement between the monotonous and sharp pressure profiles is an indication that the pressure profile will be different for each piston and cylinder unit due to material variances.

Analysis of Cylinder Compression Pressure & Valve Timing by Motoring Current & Crank Signal during Cranking (모터링시 전류 파형과 크랭크각 센서를 이용한 기관의 압축압력 및 밸브 타이밍 분석)

  • Kim, In-Tae;Park, Kyoung-Suk;Shim, Beom-Joo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.5
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    • pp.45-50
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    • 2011
  • Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.

An Experimental Study on Oil Pressure Distribution in the Piston-Cylinder Mechanism (피스톤-실린더 기구에서 오일압력 분포에 관한 실험적 연구)

  • Kim, Yeong-Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.6
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    • pp.77-82
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    • 2011
  • The piston-cylinder mechanism is widely adopted in the hydraulic machine components. In these cases, the hydrodynamic pressures are generated in the clearance gap between the piston and cylinder under lubrication action of the piston. Under the eccentric and tilted condition of the piston in the cylinder bore, the non-symmetric pressure distributions in the circumferential direction result in lateral forces. When the lateral forces act as increasing the eccentricity and tilting ratios, excessive wear can be result in cylinder and piston which are well known 'hydraulic locking' phenomena. In this paper, the hydrodynamic pressures generated in the clearance are measured using a stationary piston and moving cylinder apparatus. The experimental results showed that the hydrodynamic pressure distributions are highly affected by the speed and eccentricity of the cylinder and the oil viscosity.

The Design, Structural Analysis and High Pressure Chamber Test of a Thick Pressure Cylinder for 2000 m Water Depth (수심 2000m 용 두꺼운 내압용기의 설계, 구조해석과 내압시험)

  • Choi, Hyeuk-Jin;Lee, Jae-Hwan;Kim, Jin-Min;Lee, Seung-Guk;Maring, Kothilngam
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.2
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    • pp.144-153
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    • 2016
  • This paper aims to demonstrate the design, structure analysis, and hydrostatic pressure test of the cylinder used in 2000m water depth. The cylinder was designed in accordance with ASME pressure vessel design rule. The 1.5 times safety factor required by the general rule was applied to the design of the cylinder, because ASME rule is so excessive that it is not proper to apply to the hydrostatic pressure test. The finite element analysis was conducted for the cylinder. The cylinder was produced according to the design. The hydrostatic pressure test was conducted at the hyperbaric chamber in KRISO. The results of finite element analysis(FEM) and those of the hydrostatic pressure test were almost the same, which showed that the design was exact and reliable.