• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2041_2042
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• 2009

The diagnostic/prognostic problems for condition based maintenance or Prognostics and Health Management has been used. Primary objectives of diagnosis/prognosis are maximizing system availability and minimizing downtime from fault isolation through more effective troubleshooting efforts. Diagnosis aims to detect the onset of failures to improve system performance and reduce life cycle cost by reducing the failure time. The prognosis can reduce operational and support total ownership cost and improve safety of machinery and complex systems. In this Paper, a fault diagnosis methodology has been described using a monopropellant propulsion system model as a test bench.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.694-700
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• 2013

The design of the exhaust manifold for the pulse converters of a 4 strokes high power medium-speed diesel engine is presented in terms of fatigue analysis. The said system undergoes thermal expansion due to high temperature of exhaust gas and is exposed to intrinsic vibration of the internal combustion engine. Moreover, the exhaust pulse generates pressure pulsating along the runner inside manifold. Under such circumstances, the design and construction of exhaust manifold must be carried out in a way to prevent early failure due to fracture. To validate the design concept, a test rig was developed to simulate the combination of thermal and vibrational movements, simultaneously. Experimental results showed that a certain sense of reliability can be achieved by considering a field factor obtained from the results of engine bench tests.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.796-799
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• 2007

In the bench scale test unit consisting of four commercial filter elements, the traces of the transient pressure around the nozzle and overpressure in the filter cavity were measured to estimate the effect of nozzle on pulse cleaning. For the given pulse cleaning system, the convergent nozzle displayed better performance than the straight one. The optimum ratio of outlet to inside diameter of convergent nozzle was determined, which minimized the pulse gas consumption and maximized the entrainment effect. The angle and height of nozzle convergent part was also optimum operational condition, which is meaningful to the industrial applying.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.39-47
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• 2003

UEGI (Unburned Exhaust Gas Ignition) is an alternative method for fast light-off of a catalyst. It ignites the unburned exhaust mixture using two glow plugs installed in the upstream of the close-coupled catalysts. In addition, a hydrocarbon adsorber was applied to the UEGI, for more effective reduction of HC emission. Engine bench tests show that the CCC reaches the light-off temperature laster than the baseline exhaust system and HC and CO emissions are reduced significantly during the cold start. From the vehicle test, it was observed that a few amount of HC emission was reduced even the catalysts were aged. It is expected to develop a solution kit applicable to a new vehicle or used one, to meet the emission regulation

• 한국자동차공학회논문집
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• 제12권3호
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• pp.27-36
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• 2004

A Numerical analysis has been used to predict the performance in the automotive water pump with double discharge single suction. The influence of parameters such as coolant flow rate, rotational speed, ratio of blade height and clearance has been investigated. Also, the prediction of hydraulic performances such as static pressure rise, shaft power, hydraulic power and pump efficiency is carried out on the water pump including an impeller and a volute casing. A full size water pump test bench has been developed to validate the CFD flow model. Discharge flow rate, suction pressure, discharge pressure, rotational speed and torque measurements are provided. Coolant temperature is 8$0^{\circ}C$, water tank pressure is 1 kgf/$\textrm{cm}^2$ and flow rates vary.

• 오토저널
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• 제13권4호
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• pp.85-93
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• 1991

Engine oil of the vehicle is very important to reduce friction and wear of the moving parts as long as possible without deterioration. As the technique of engine design and manufacturing improves, the performance of engine was increased greatly with the improvement of the quality of engine oil. All the additives and formulations skill of engine oil produced in our country are imported from foreign country. So it is necessary to study the basic knowledge of the mechanism of friction and wear of engine oil for the development of our own formula and additives. From this research, the basic mechanism of tribology and the change of oil properties were studied with a home made oil and two foreign oils by bench and engine test and laboratory works.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.127-133
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• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.43-49
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• 2003

The common-rail fuel injection system is becoming a common technology for High Speed Direct Injection(HSDI) diesel engines. The injection timing and rate are important factors for combustion control and pollutants formation mechanisms during engine operation. This paper introduces an estimation methodology of the injection timing and rate of a common-rail injector for HSDI diesel engines. A sliding mode observer that is based on the nonlinear mathematical model of the common-rail injector is designed to overcome the model uncertainties. The injector model and the estimator we verified by relevant injection experiments in an injector test bench. The simulation and the experimental results show that the proposed sliding mode observer can effectively estimate the injection rate of the common-rail injector.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.26-36
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• 2010

This paper provides a description of the combustion model to obtain an accurate dynamic engine phenomena that satisfies real-time simulation for model-based engine control. The combustion chamber is modeled as a storage device for mass and energy. The combustion process is modeled in terms of a two-zone model for the burned and unburned gas fractions. The mass fraction burnt is modeled in terms of a Wiebe function. The instantaneous net engine torque is calculated from the engine speed and the instantaneous piston work. The modeling accuracy has been tested with a cylinder pressure data on a test bench and also the ability of real-time simulation has been checked. The results show that combustion model yields sufficiently good performance for the model-based control logic design. However the influence factors effected on model accuracy are some room for improvement.

• 기술사
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• 제23권6호
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• pp.41-46
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• 1990

First of all, Under given condition such as bit gage of 36mm Drill bit with right class of jack-logs experimental test carried out from two face of Bench, firing of each hole brought 90 degree Angle face and them measured length of Burden and charged ammount of powder as following. (equation omitted) A=Activated Area A=ndi=m S=Peripheral length of Charged. room Ca=Rock Coeffiecency d : di=Hole diameter When constructed subway of Seoul in 1980 the blasting works increased complaint of ground vibration. in order to prevent the damage to structures. Some empirical equations were made as follows on condition with Jackleg Drill (Bit Gage ø 36mm) and within 30 meter distance between blasting site and structures. V=K(D / W)$\^$-n/ N=1.60-1.78 K=48-138 Project one of contineous works to above a determination of empirical equation on the cautious blasting vibration with Crawler Drill(ø 70-75mm) in long distance. V=41(equation omitted) V=124(equation omitted).