• Title/Summary/Keyword: In-Cylinder Gas Flow

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A Study on the Gas Flow in Exhaust Manifold of a Single Cylinder Diesel Engine (단기통 디젤 기관의 배기관 가스유동에 관한 연구)

  • Lee, J.Y.;Koh, D.K.;Cho, K.H.;Jang, S.H.;Ahn, S.K.
    • Journal of Power System Engineering
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    • v.7 no.1
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    • pp.14-19
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    • 2003
  • A diesel engine has been widely used for ship and industry power because it has many merits of high thermal efficiency, reliability and durability. However its exhaust gas is harmful to human and air environment. Reducing the hurtful exhaust gas emissions, the study of the gas flow in the inlet and exhaust manifold is in progress in the world. In this paper we modeled the gas flow as one dimensional isentropic flow to predict the gas flow in the exhaust manifold. The method of characteristics was used for the model calculation, and the calculated results were compared with the experimental ones.

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A Study on Engine Durability Considering Oil Consumption and Wear of Piston-Ring Pack and Cylinder Bore (피스톤 링 팩 및 실린더 보아 마모와 오일소모를 고려한 엔진 내구수명 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.155-163
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    • 2006
  • Ring, groove and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face, groove geometry and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blowby and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings, grooves and cylinder bore are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below.

A Study on Cylinder Bore Wear during Engine Durability Test (엔진 내구시험 시 실린더 보아의 마모에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.131-136
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    • 2006
  • Cylinder bore wear may not be a problem in most current automotive engines. However, a small change in cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each pare0s wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of cylinder bore diameter are obtained from three engines before and after engine durability test. The calculated wear data of cylinder bore diameter are turn out to be twice of the lower bound of averaged test values at TDC and the lower bound at BDC.

A Study on the Optimization of Cylinder Head Port Flow for Hyundai H21/32 Medium-Speed Diesel Engines (현대 H21/32 중속 디젤엔진 실린더 헤드포트 최적화 연구)

  • Kim, Byung-Yoon;Kim, Jin-Won;Ghal, Sang-Hak
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.806-811
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    • 2001
  • Since the characteristics of combustion and pollutant in Diesel engines were mainly effected by the characteristics of in-cylinder gas flow and fuel spray, an understanding of those was essential to the design of the D.I. Diesel engines. The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve shape influence greatly to the volumetric efficiency, it is very important to investigate the flow characteristics of intake and exhaust port which develops air motion in the combustion chamber. In this study, two approach methods were used for design intake and exhaust port; experiment and computation which were made by using steady flow test rig and commercial CFD code. This paper presents the results of an experimental and analytical investigation of steady flow through the prototype cylinder head ports and valves of the HHI's H21/32 HIMSEN Engine.

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NOx removal in cylinder type reactor and Packed-bed type reactor (원통형과 packed-bed형 반응기에서 NOx제거특성)

  • 박재윤;박상현;이경호;하상태;송원섭;황보국
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.499-502
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    • 2001
  • In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using cylinder type reactor and packed-bed reactor. An experimental investigation has been conducted for NO concentration of 50[ppm], 100[ppm], 200[ppm] balanced with air, a gas flow rate of 5[1/min]. Ac voltage to discharge the gases was supplied. In the result, NOx removal rate in packed bed reactor is higher than that in cylinder type reactor. it is thought that plasma density in contact point of BaTiO$_3$ is significantly higher than that in cylinder reactor.

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Catalistic effect of sludge on $NO_x$ removal in cylinder type reactor (원통형 플라즈마 반응기에서 $NO_x$ 제거에 미치는 슬러지의 촉매효과)

  • Park, Jae-Yoon;Lee, Kyung-Ho;Park, Sang-Hyun;Kim, Hyung-Man;Kim, Jong-Suk;Ha, Hyun-Jin
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1777-1779
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    • 2001
  • In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using cylinder type reactor. An experimental investigation has been conducted for NO concentration of 50[ppm], 100[ppm], 200[ppm] balanced with air. a gas flow rate of 5[1/min]. Cylinder type reactor is at upstream of system for corona discharge and packed bed type reactor filled with sludge pellets ate put at downstream of Cylinder type reactor for catalystic effect. And AC voltage to discharge the gases was supplied. In the result, NO removal with magnetic field is higher than that without magnetic field, when packed-bed reactor with sludge pellet is installed at downstream of cylinder reactor NO, $NO_2$ removal rate increased and $O_3$ is not generated.

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An Experimental Study on Internal Temperature Changes of Type Ⅳ Cylinder according to Filling with Compressed Hydrogen Gas (압축수소가스 충전에 따른 타입 IV 용기의 온도 변화에 관한 실험적 연구)

  • Lee, Seung-Hoon;Kim, Youn-Gyu;Yoon, Kee-Bong
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.644-647
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    • 2009
  • In this paper, the study is researched for related safety standards having experiments concerning temperature changes in type IV cylinder of the Hydrogen fuel cell vehicle. Experiments were performed to acquire temperature data of type IV cylinder according to filling time. The experimental results are shown that internal temperatures of type Ⅳ vessel are over $85^{\circ}C$ at all measured points after 5 minutes at filling 35 MPa and the highest temperature is getting lower when the residual gases are more remained. Consequently, the safety standards need properly limited value through further study for filling flow rate and filling time.

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Performance Analysis of a Reciprocating Compressor Using a Real Gas Equation of State (실제기체 상태방정식을 이용한 왕복동압축기의 성능해석)

  • Kim, J.W.;Kim, H.J.;Pak, H.Y.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.4 no.4
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    • pp.306-315
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    • 1992
  • This paper addresses performance analysis of a reciprocating compressor. A computer simulation model has been developed to predict and estimate the compressor performance. Instead of using ideal gas equations, real gas equations are used in describing the state of gas. The compressor simulation model consists of a cylinder control volume, suction system and discharge system. Conservation laws of mass and energy are applied to the cylinder section only, The suction and discharge system are described by the Helmholtz resonator modeling. Some of input data required for the simulation have been obtained from experiments. These experimentally obtained input data are effective flow area, effective force area and dynamic characteristics of valves. Simulation results of real gas equations have been compared with those of ideal gas equations. It has been found that the simulation with real gas equations yields lower cylinder temperature and heat transfer compared with those of ideal gas equations. Differences in pressure, mass flowrates, valve motions and gas pulsations are found quite small.

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Experimental Study on Axial Stratification Process and Its Effects (I) - Stratification in Engine -

  • Ohm, In-Yong;Park, Chan-Jun
    • Journal of Mechanical Science and Technology
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    • v.16 no.11
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    • pp.1457-1469
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    • 2002
  • This paper is the first of several companion papers, which investigate axial stratification process and its effects in an Sl engine. The axial stratification is very sophisticate phenomenon, which results from combination of fuel injection, port and in-cylinder flow and mixing. Because of the inherent unsteady condition in the reciprocating engine, it Is impossible to understand the mechanism through the analytical method. In this paper, the ports were characterized by swir and tumble number in steady flow bench test. After this, lean misfire limit of the engines, which had different port characteristic, were investigated as a function of swirl ratio and injection timing for confirming the existence of stratification. In addition, gas fuel was used for verifying whether this phenomenon depends on bulk air motion of cylinder or on evaporation of fuel. High-speed gas sampling and analysis was also performed to estimate stratification charging effect. The results show that the AFR at the spark plug and LML are very closely related and the AFR is the results of bulk air motion.

A Numerical Analysis of Rarefied Flow of Cylinder Using FDDO (FDDO를 이용한 실린더를 지나는 희박기체의 해석)

  • Ahn M. Y.;Chang K. S.
    • 한국전산유체공학회:학술대회논문집
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    • 1998.05a
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    • pp.138-144
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    • 1998
  • The BGK equation, which is the kinetic model equation of Boltzmann equation, is solved using FDDO(finite difference with the discrete-ordinate method) to compute the rarefied flow of monatomic gas. Using reduced velocity distribution and discrete ordinate method, the scalar equation is transformed into a system of hyperbolic equations. High resolution ENO(Essentially Non-Oscillatory) scheme based on Harten-Yee's MFA(Modified Flux Approach) method with Strang-type explicit time integration is applied to solve the system equations. The calculated results are well compared with the experimental density field of NACA0012 airfoil, validating the developed computer code. Next. the computed results of circular cylinder flow for various Knudsen numbers are compared with the DSMC(Direct Simulation Monte Carlo) results by Vogenitz et al. The present scheme is found to be useful and efficient far the analysis of two-dimensional rarefied gas flows, especially in the transitional flow regime, when compared with the DSMC method.

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