• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1022-1027
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• 2011

A diesel engine works in high compression ratio due to injection of diesel fuel after compression of air. Therefore the engine has a high thermal efficiency, while nitrogen oxide is produced a lot in high flame temperature regions. In order to solve the problem this study HHO gas is added into the intake air of the industrial diesel engine. The test conditions are loads of 0%, 50% and 100% and engine speeds of 700 to 1900 rpm. The results show the maximum torque and pressure is increased, fuel consumption, smoke and CO emissions are decreased and NOx emission is remained at same level.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.73-81
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• 2005

An Experimental study was conducted to investigate the effective way for fuel consumption improvement in radiant tube burner heating system used in steel manufacturing process. To find effectiveness of increase of temperature and oxygen fraction of intake air on fuel consumption, the model radiant tube burner heating system with recuperator was designed to be able to adjust temperature and oxygen fraction of intake air, and was operated under various conditions with oxygen concentration in exhaust gas changed. The results show that burner chamber temperature was increased about $10\%$ of intake air temperature increase. so it was difficult to expect fuel consumption improvement. But only 1 or $2\%$ increase of oxygen fraction in intake air made a significant improvement in fuel consumption even though it made much NOx emissions also. Therefore, if NOx emissions is controlled under regulation with burner modification, it is expected that increase of oxygen fraction in Intake air is effective way to improve fuel consumption.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.911-917
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• 2013

This is a thesis about the experiment of comparison characteristic of power and exhaust gas in the same condition between diesel engine that is equipped response power 220HP turbocharger to increase effectiveness of the engine which is recently used in a lot of industry which requires high power. Resulting of the experiment with natural aspiration diesel engine and turbocharger diesel engine, difference in low speed is not significant, but in high speed, effectiveness of turbocharger diesel engine is much higher than the other one. In other hand, in exhaust gas experiment, turbocharger model exhausts more $NO_X$ and $O_2$, but it doesn't significantly affect the result when it comes with decreasing of $CO_2$ and effectiveness of increased power characteristic. As a result, the turbocharger diesel engine is economically effective comparing with the natural aspiration diesel engine.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.766-772
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• 2000

Background : Pressure rise time (PRT) is the time in which the ventilator aclieves the set airway pressure in pressure-targeted modes, such as pressure control ventilation (PCV). With varying PRT, in principle, the peak inspiratory flow rate of the ventilator also varies. And if PRT is set to a shorter duration, the effective duration of target pressure level would be prolonged, which in turn would increase inspiratory tidal volume(Vti) and mean airway pressure (Pmean). We also postulated that the increase in Vti with shortening of PRT may relate inversely to the patients' basal airway resistance. Methods : In 13 paralyzed patients on PCV (pressure control 18$\pm$9.5 cm $H_2O$ $FIO_2\;0.6\pm0.3$, PEEP 5$\pm$3 cm $H_2O$, f 20/min, I : E1 : 2) with Servo 300 (Siemens-Elema, Solna, Sweden) from various causes of respiratory failure, PRT of 10 %, 5 % and 0 % were randomly applied. At 30 min of each PRT trial, peak inspiratory flow (PIF, L/sec), Vti (ml), Pmean (cm $H_2O$) and ABGA were determined. Results : At PRT 10%, 5%, and 0%, PIF were 0.69$\pm$0.13, 0.77$\pm$0.19, 0.83$\pm$0.22, respectively (p<0.001). Vti were 425$\pm$94, 439$\pm$101, 456$\pm$106, respectively (p<0.001), and Pmean were 11.2$\pm$3.7, 12.0$\pm$3.7, 12.5$\pm$3.8, respectively (p<0.001). pH were 7.40$\pm$0.08, 7.40$\pm$0.92, 7.41$\pm$0.96, respectively (p=0.00) ; $PaCO_2$ (mm Hg) were 47.4$\pm$15.8, 47.2 $\pm$15.7, 44.6$\pm$16.2, respectively (p=0.004) ; $PAO_2-PaO_2$ (mm Hg) were 220$\pm$98, 224$\pm$95, 227$\pm$94, respectively (p=0.004) ; and $V_n/V_T$ as determined by ($PaCO_2-P_E-CO_2$)/$PaCO_2$ were 0.67$\pm$0.07, 0.67$\pm$0.08, 0.66$\pm$0.08, respectively (p=0.007). The correlation between airway resistance and change of Vti from PRT 10% to 0% were r= -0.243 (p=0.498). Conclusion : Shortening of pressure rise timee during PCV was associated with increased tidal volume, increased mean airway pressure and lower $PaCO_2$.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.105-106
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• 2012

This study is numerical analysis about optimal conditions of GDICI (gasoline direct injection compression ignition) engine operation using intake preheating. Numerical modeling was performed by using the KIVA-3V Release2 code integrated Chemkin chemistry solver II. For validation of numerical model, experiments were performed on a single-cylinder engine. Throughout the numerical simulations under variable conditions, the ranges of optimal conditions were found.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.26-26
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• 2001

소형항공기용 IO-540 왕복엔진을 대상으로 추진기관의 성능에 미치는 배압 특성을 조사하기 위해서 지상 성능시험을 수행하였다. 본 시험은 6가지 배기조건에 대해서 엔진의 배압과 흡기압력, 토크, 그리고 프로펠러의 정지추력을 측정하였다. 엔진의 배압은 대체로 머플러를 장착할 경우와 배기관 끝단이 상대적으로 직경이 작고 길이가 길수록 증가하였다. 배압 특성은 특히 엔진의 회전속도가 고속 영역으로 갈수록 프로펠러 추력에 변화를 나타냈으며 전반적으로 추진기관 성능에 미세한 영향을 미치는 것으로 나타났다.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.183-189
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• 2003

The study of the automotive noise reduction has been concentrated on the reduction of the automotive engine noise because the engine noise is the major cause of automotive noise. However, many studies of automotive engine noise led to the interest of the noise reduction of the exhaust and intake system. Recently, the active control method is used to reduce the noise of an automotive exhaust and intake system. It is mostly used the LMS(Least-Mean-Square) algorithm as an algorithm of active control because the LMS algorithm can easily obtain the complex transfer function in real-time. Especially, Filtered-X LMS (FXLMS) algorithm is applied to an Active Noise Control system. However, the convergence performance of LMS algorithm went bad when the FXLMS algorithm was applied to an active control of the induction noise under rapidly accelerated driving conditions. So, in order to solve this problem, the modified FXLMS algorithm is proposed. In this study, the improvement of the control performance using the modified FXLMS algorithm under rapidly and suddenly accelerated driving conditions was identified. Also, the performance of an active control using the LMS algorithm under rapidly accelerated driving conditions was evaluated through the theoretical derivation using a chirp signal to have similar characteristics with the induction noise signal.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.422-429
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• 1990

The experimental study investigates two aspects of counterflow sensible heat regenerator operation. First, it examines the regenerator performance in periodic steady state operation with spatially nonuniform inlet temperature in one of the fluid stream. Second, the study examines the transient response of a regenerator to a step change in the inlet temperature of one of the fluid streams. The effect of transient inlet temperatures is analyzed in terms of the response of the outlet fluid temperatures to a step change in temperature of one of the inlet fluid streams. The effect of temperature nonuniformities is analyzed in terms of the change of temperature nonuniformities is analyzed in terms of the change in steady state effectiveness due to a circumferential temperature distribution in one of the inlet fluid streams. an experimental analysis has been conducted using a counterflow, parallel passage, and rotary regenerator made from polyethylene film. Efficiencies follow similar trends with increasing matrix to fluid capacity rate ratio for the balanced and symmetric regenerator with nonuniform inlet temperature.

• Journal of ILASS-Korea
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• v.15 no.1
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• pp.1-7
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• 2010

As world attention has focused on global warming and air pollution, high efficiency diesel engines with low $CO_2$ emissions have become more attractive. Premixed diesel engines in particular have the potential to achieve the more homogeneous mixture in the cylinder which results in lower NOx and soot emission. Early studies have shown that the operation conditions such as the EGR, intake conditions, injection conditions and compression ratio are important to reduce emissions in a PCCI (Premixed Charge Compression Ignition) engine. In this study a modified cam was employed to reduce the effective compression ratio. While opening timing of the intake valve was fixed, closing timing of the intake valve was retarded $30^{\circ}$. Although Atkinson cycle with the retarded cam leads to a low in-cylinder pressure in the compression stroke, the engine work can still be increased by advanced injection timing. On that account, we investigated the effects of various injection parameters to reduce emission and fuel consumption; as a result, lower NOx emission levels and almost same levels of fuel consumption and PM compared with those of conventional diesel engine cam timing could be achieved with the LIVC system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.6
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• pp.1921-1930
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• 1996

To design an optimum engine intake system, a flow model for the intake manifold was developed by the finite difference method. The flow in the intake manifold was one-dimensional, and the finite difference equations were derived from governing equations of flow, continuity, momentum and energy. The thermodynamic properties of the cylinder were found by the first law of thermodynamics, and the boundary conditions were formulated using steady flow model. By comparing the calculated results with experimental data, the appropriate boundary conditions and convergence limits for the flow model were established. From this model, the optimum manifold lengths at different engine operating conditions were investigated. The optimum manifold length became shorter when the engine speeds were increased. The effect of intake valve timings on inlet air mass was also studied by this model. Advancing intake valve opening decreased inlet air mass slightly, and the optimum intake valve closing was found. The difference in inlet air mass between cylinders was very small in this engine.