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흡입밸브 각이 실린더 내 와류 발생 특성에 미치는 영향(Ⅰ)
엄인용(Inyong Ohm),박찬준(Chanjun Park) 한국자동차공학회 2008 한국 자동차공학회논문집 Vol.19 No.6
This paper is the first of 2 companion papers which investigate in-cylinder swirl generation characteristics according to inlet valve angle. Two DOHC 4 valve engines, one has wide intake valve angle and the other has narrow valve angle, were used to compare the characteristics of swirl motion generation in the cylinder. One intake port was deactivated to induce swirl flow. A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field according to inlet valve angle during intake stroke. The results show that the stronger swirl motion is observed in wide valve angle engine at the early intake stage; however, the swirl motion is gradually distorted by the intake flow component passing through valve area near the cylinder wall as the stroke proceeds. The tumble motion also does so in wide angle. On the contrary, the swirl and tumble motions, which are not clear at the initial stage, become better and better arranged as the piston goes down and up again after bottom dead center.
흡입밸브 각이 실린더 내 와류 발생 특성에 미치는 영향(Ⅱ)
엄인용(Inyong Ohm),박찬준(Chanjun Park) 한국자동차공학회 2009 한국 자동차공학회논문집 Vol.17 No.2
This paper is the second of 2 companion papers which investigate in-cylinder swirl generation characteristics according to inlet valve angle. Two DOHC 4 valve engines, one has wide intake valve angle and the other has narrow valve angle, were used to compare the characteristics of swirl motion generation in the cylinder. One intake port was deactivated to induce swirl flow. A PIY (Particle Image Velocimetry) was applied to measure in-cylinder velocity field according to inlet valve angle during intake stroke. The results show that the flow patterns of narrow valve engine are much more stable and well arranged compared with the normal engine over the entire intake and compression stroke except early intake stage, and very strong swirl motion is generated at the end of compression stage in this engine nevertheless using straight port which is unfavorable for swirl generating. In the wide valve angle one, however, strong swirl motion induced during intake stroke is destroyed as the compression progresses.
밸브 각이 큰 나선형 포트 엔진의 실린더 내 압축 유동 특성
엄인용(Inyong Ohm),박찬준(Chanjun Park),김형식(Hyeongsik Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Two wide valve-angle engines, which are same ones and have slightly different rig swirl number, were used to compare the characteristics of cylinder-flow. One intake port is deactivated to induce swirl flow. A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field during intake stroke. The results show that the intake flow component passing through valve area near the cylinder wall is not negligible in helical port engine with wide valve angle contrary to conventional one. The effect of this velocity component on in-cylinder increases as the swirl ratio rises and compression process progresses. Consequently, this component destroys in-cylinder swirl flow completely during compression resulting in no actual swirl at the end stage of compression.
밸브 각이 큰 나선형 포트 엔진의 실린더 내 흡입 유동 특성
엄인용(Inyong Ohm),박찬준(Chanjun Park),김형식(Hyeongsik Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Two wide valve-angle engines, which are same ones and have slightly different rig swirl number, were used to compare the characteristics of cylinder-flow. One intake port is deactivated to induce swirl flow. A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field during intake stroke. The results show that the intake flow component passing through valve area near the cylinder wall is not negligible in helical port engine with wide valve angle contrary to conventional one. The effect of this velocity component on in-cylinder increases as the swirl ratio rises and intake process progresses. Consequently, this component interferes the formation of in-cylinder swirl flow resulting in lower actual swirl.
이정빈,양동학,김성육,오범석,김기선 한국기계기술학회 2015 한국기계기술학회지 Vol.17 No.5
A Blast valve is the device that is used in the air intake and the exhaust vent of CBRN(Chemical, Biological, Radiological and Nuclear warfare) protection facility. The valve is automatically closed when explosion pressure is applied from the outside of equipment. In this study we modeled the blast valve assembly that connected duct. After modeling we examined the air flow pattern like the velocity and pressure distribution, vortex form that generated in rear of disc, the area of recycle based on the results of the flow analysis in order to analyze the principal factors that affect the valve.
흡입 밸브 각도에 따른 압축 행정 중 실린더 내 유동 특성
엄인용(Inyong Ohm),박찬준(Chanjun Park) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.4
A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field according to inlet valve angle during compression stroke. Two engines, one is conventional DOHC 4 valve and the other is narrow valve angle, were used to compare real compression flow. The results show that the flow patterns are well arranged compared with intake flow and the basic tumble flow structures are maintained until end compression stage regardless of valve angle. Also the results show that the tumble motion is intensified by momentum conservation during compression in normal engine. In the normal engine, the bulk shape of flow pattern is “Y” type at the top of cylinder and reverse “Y” type at the bottom of cylinder and weak reverse flow exists at the top of cylinder along cylinder center line. Otherwise, the other engine's flow pattern changes from “Y” type to “T” type at the top of cylinder during compression.
김진수(Jinsu Kim),허형석(Hyungseok Heo),배석정(Sukjung Bae),박준영(JunYoung Park),서형준(Hyeongjun Seo) 한국자동차공학회 2015 한국자동차공학회 부문종합 학술대회 Vol.2015 No.5
Gasoline EGR systems have been used for improving fuel efficiency by reduction of no nocking and pumping loss, recently. Analytical design has been conducted for a few of models of poppet type electric EGR valve in search of adequate model furnishing the required flow rate. The parametric study has been performed with respect to the parameters such as the poppet and seat angles.
배관 압력을 이용한 방향제어밸브 위상각 대역폭 주파수 측정에 관한 연구
김성동(Sungdong Kim),이정은(Jung-eun Lee),신대영(Daeyoung Shin) 유공압건설기계학회 2018 드라이브·컨트롤 Vol.15 No.4
Spool displacement of a direction control valve is the standard signal to measure the bandwidth frequency of the direction control valve. When the spool displacement signal is not available, it is suggested in this study to use the metering hydraulic line as an alternative way to measure – 90 degree phase bandwidth frequency of the hydraulic direction control valve. Dynamics of the hydraulic line is composed of inertia, capacitance, and friction effects. The effect of oil inertia is dominant in common hydraulic line dynamics and the line dynamics is close to a derivative action in a range of high frequency; such as a range of bandwidth frequency of common directional control valves. Phase difference between spool displacement and line load pressure is nearly constant as a valve close to 90 degree. If phase difference is compensated from the phase between valve input and pressure, compensated phase may be almost same as the phase of spool displacement that is a standard signal to measure phase bandwidth frequency of the directional control valve. A series of experiments were conducted to examine the possibility of using line pressure in to measure phase bandwidth frequency of a directional control valve. Phase bandwidth frequency could be measured with relatively high precision based on metering hydraulic line technique and it reveals consistent results even when valve input, oil temperature, and supply pressure change.
미터링 오리피스를 이용한 방향제어밸브 위상각 대역폭 주파수 측정에 관한 연구
김성동,전세형,윤주섭 사단법인 유공압건설기계학회 2018 드라이브·컨트롤 Vol.15 No.1
The spool displacement of directional control valve can be considered as the standard signal to measure the bandwidth frequency of a directional control valve. When the spool displacement is not available, the metering-orifice system is implemented in this research as an alternative way of measuring the 90 degrees phase bandwidth frequency of the hydraulic directional control valve. The inertia effect on the transmission line oil induces the phase lead of the valve load pressure when compared with the phase of spool displacement. The capacitance effect of the oil induces the phase lag of the valve load pressure. The phase of the load pressure can be adjusted to be the same as that of the spool displacement by controlling the opening area of the metering orifice. A series of experiments were conducted to verify the effectiveness of the metering orifice. The 90 degrees phase bandwidth frequency measured from the valve load pressure was significantly deviated in some cases from the frequency of the spool displacement. The metering orifice was hard to be applied to measure the –90 degrees phase bandwidth frequency of the high precision.
나선형 포트를 적용한 광각엔진에서 실린더 내 흡입 유동 특성
엄인용(Inyong Ohm),박찬준(Chanjun Park) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.10
This paper is the first of 2 companion papers which investigate in-cylinder swirl generation characteristics in helical port engine with wide valve angle. Two wide valve-angle engines, which are same ones and have slightly different rig swirl number, were used to compare the characteristics of cylinder-flow. One intake port is deactivated to induce swirl flow. A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field during intake stroke. The results show that the intake flow component passing through valve area near the cylinder wall is not negligible in helical port engine with wide valve angle contrary to conventional one. The effect of this velocity component on in-cylinder increases as the swirl ratio rises and intake process progresses. Consequently, this component interferes the formation of in-cylinder swirl flow resulting in lower actual swirl.