• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.461-462
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.817-818
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• 2011

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.13-13
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• 2003

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.563-568
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• 2007

A separate triangular bar type differential pressure flow meter was developed for measuring exhaust gas flow rate from Diesel engine. Three kinds of the separate triangular bar flow meters whose aerodynamic angles are different one another are made and evaluated, respectively. The experimental results show that an aerodynamic shape has a effect on the pressure difference between upstream and downstream at the flow meter, that is, the thinner the shape of the separate triangular bar flow meter is, the smaller the pressure difference at the flow meter is. The separate triangular bar type flow meter was calibrated at both cold and high temperature of the gas flow. A burner system was designed for raising the gas temperature and it was well operated in controlling the gas temperature. An empirical correlation between mass flow rate and differential pressure at the separate triangular bar flow meter was obtained and the empirical correlation was also corrected by the gas temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.3
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• pp.21-32
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• 1994

The Problem of mechanical vibration is investigated for an automotive exhaust system. The vibrational reduction effect is systematically evaluated according to the attachment of the exhaust system. Moreover, the optimal attachment position of bellows is determined from the viewpoint of vibration isolation. The structure is analysed by the finite element technique where the geometry, the mass, the stiffness and the damping properties of the exhaust pipe are modeled. The validity of the developed model is verified by comparing with the experimental results. An optimization is carried out by the quadratic approximation algorithm. The reaction transferred to an automobile body by the hanger is considered ad the objective function. It is shown that the exhaust system which has the bellows at the optimal position is more effective for the vibrational characteristics than the others. It is also proved that this analytical method is quite useful in the design stage of the exhaust system.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.35-43
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• 2006

A four-stroke four-cylinder turbocharged diesel engine can be fitted with various types exhaust system. In this paper, the impacts of exhaust system design on scavenging performance and wave action characteristic during valve overlap are investigated by using one-dimensional gas dynamic code. This work shows that a huge reflected exhaust pressure waves which reaches the exhaust port during valve overlap period is crucial design factor which determines quality and quantity of the fresh charge. Hence pressure wave that reaches the exhaust port of the cylinder during the valve overlap sequence should be weakened for good scavenging performance. This paper describes advantages and disadvantages of the various exhaust systems applied to a turbocharged and intercooled 4-cylinder diesel engine system in terms of scavenging efficiency and engine performance. To verify the computational results, experimental comparison has also performed.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.45-45
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• 2010

반도체 및 디스플레이 산업에 사용되는 진공펌프의 효율이 증대됨에 따른 성능 평가 기술의 향상 과 미세 유량을 조절 및 측정할 수 있는 시스템의 개발이 요구되고 있다. 유량 시스템 중 소닉노즐은 기체 유량 측정 표준기로 사용되고 있다. 또한 유량 측정에 있어서 사용상의 편리성, 이동성, 재현성 등 여러 가지의 장점을 가지고 있어 산업 현장에서 많이 사용되고 있다. 본 연구는 소닉노즐을 넓은 유량 범위에서 사용할 수 있도록 소닉노즐의 유출계수 교정을 목적으로 한다. ISO 9300에서 제시한 사양에 맞추어 목 직경 0.03 mm와 0.2 mm 그리고 1.6 mm의 소닉노즐을 제작하였다. 한국표준과학연구원에서 진공용 유량측정 장치로 개발된 정적형 유량계를 이용하여 제작된 3 종의 소닉노즐 유출계수를 확장불확도 3% 이내로 교정하였다. 교정된 소닉노즐의 유량 측정범위는 약 0.6~90, 000 cc/min 범위를 갖는 것으로 나타났으며, 사용유동 조건에 해당되는 레이놀드 수(Reynolds number) 범위는 26~75, 700 으로 확인되었다. 이러한 결과는 교정된 소닉노즐을 이용하여 진공공정에서 필요한 극 미세 유량의 정밀측정을 가능하게한 새로운 연구결과로 판단된다. 교정된 소닉노즐을 이용하여 진공펌프의 배기속도 측정결과는 기 구축된 정적법을 이용한 배기속도 측정결과와 3% 이내의 오차범위내로 매우 잘 일치함을 보였다. 교정된 소닉노즐은 향후 반도체 및 디스플레이 공정에 사용되는 다양한 진공펌프들의 배기속도를 현장에서 간단하게 평가할 수 있는 '현장 성능평가 장치'에 활용할 예정이며, 현재 공정현장에서 배기속도 측정에 널리 사용 중인 MFC를 대체할 수 있을 것으로 예상된다.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.312-320
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• 2001

A Non-Evaporable Getter(NEG) pump was fabricated using Zr-V-Fe alloy modules to obtain $10^{-9}$ Pa range pressures. Pumping performances and activation characteristics were investigated and the pumping speeds for hydrogen, deuterium and carbon monoxide gases of the NEG pump were measured. And hydrogen desorption characteristics were examined during activation at $450^{\circ}C$. Futhermore the vacuum performance was compared with those of other high vacuum pumps as turbo-molecular pump, sputter-ion pump, and cryo pump by analyzing the residual gases of the system.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.52-59
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• 2000

Experimental studies were performed to improve the THC emission characteristics by optimizing the flow in the exhaust manifold and CCC in a SI engine. For this purpose the flow characteristics in the exhaust manifold and CCC were measured by using LDV technique under various engine conditions, Referring to these data a new type exhaust manifold was designed to improve the cold-start emission characteristics and the response characteristics of {{{{ OMICRON _2}}}} sensor by optimizing the flow pattern and reducing the thermal inertia of the exhaust manifold system. It was found through the vehicle emission tests that the emission characteristics of THC of the new type exhaust manifold was improved by 12% through the optimizing the flow pattern in the exhaust manifold.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.37-42
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• 2010

This paper deals with the sealing mechanism of the gasket component and the effects of design parameters for the exhaust manifold. The finite element model includes hot-end exhaust system and a simplified gasket model supplied by ABAQUS software. The mechanical behaviors of bead and body of a gasket are measured after several times of cyclic loads by gasket supplier. From the finite element analysis due to the cyclic thermal loads, the flange of exhaust manifold shows thermal expansion and contraction in longitudinal direction as well as convex and concave deformations with respect to the engine cylinder head. And, the contact pressures of the gasket beads suddenly changes by normal deformation of inlet flanges. Therefore, the magnitudes of contact pressures could be used to determine the sealing characteristics of the exhaust gas in the exhaust system. The distributions of contact pressures in gasket bead lines shows a good agreement with the engine test results.