• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.625-628
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• 2005

Silencers are extensively used for reducing noise in an exhaust system of internal combustion Engine and fluid machineries. The prediction and measurement of the transmission loss as the acoustic performance of silencers are important in early design stage. In the measurement of transmission loss, the semi-anechoic terminations are general used for reducing unwanted effects by reflecting wave. However it is very hard to remove reflecting wave perfectly. So the research about the error made by reflecting wave is important. The analysis about errors made by reflections and modification techniques are proposed. For an application example, the diesel particulate filter (DPF) is chosen. The transmission loss of DPF is measured with and without considerations of reflecting wave.

• 멤브레인
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• 제8권3호
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• pp.117-129
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• 1998

경유자동차에 의한 오염물질의 배출은 주로 입자상물질과 NO$_x$가 문제시되고 있는데 특히 입자상물질은 각종 호흡기질환의 원인 등으로 간주되어 이의 규제가 국내외적으로 강화되고 있다. 본 고에서는 이러한 입자상 물질을 제거하기 위하여 사용되는 각종 필터의 특성 및 제조방법에 대하여 알아보고자 하였다. 이를 위하여 먼저 경유자동차에서 발생하는 오염물질 및 이의 규제현황에 대하여 다루었으며 각종 후처리장치의 종류 및 개발현황에 대하여 언급하였다. 다음으로 가장 일반적으로 사용되어지는 필터인 세라믹 하니컴 필터를 중심으로 하여 원료 및 소재, 제조방법 그리고 열팽창계수의 조절 등에 대하여 논하였다.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.95-100
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• 2005

Since air pollution has become a globally critical issue and exhaust emissions from automobiles cause a major source of air pollution, many countries including advanced countries have stipulated stringent emission regulations. This research focused on engine performance characteristics with the application of a continuous regeneration diesel particulate filter and EGR together in a heavy duty vehicle, and gives some suggestions on the direction of designing points of view by comparing the experimental data with numerical results which were obtained through KIVA-3V.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.195.1-195
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• 2002

• 한국어류학회지
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• 제21권3호
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• pp.141-148
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• 2009

Oryzias dancena를 해양생태계 위해성 평가를 위한 해양 생물모델로 연구하기 위한 기초적인 연구로 초기 성분화와 생식소 발달 과정을 조직학적으로 조사하였다. 원시생식세포가 처음 관찰된 시기는 수정 후 5일째이고, 수정 후 9일째에 장과 앞신장관 사이의 생식소 형성 부근으로 이동한 것이 관찰되었다. 부화 후 12일째의 생식소는 암 수로 분화가 이루어졌다. 부화 후 28일째 난소에서는 주변인기의 난모세포가 관찰되었으며, 28일째의 정소에서는 정소 소관의 수와 정원세포의 증가를 확인할 수 있었다. 산란은 부화 후 9주째에 이루어졌으며, 이 시기의 난소에서는 난황과립이 난 전체에 형성되는 성숙난과 배란 직후 성숙난이 빠져나간 흔적이 관찰되었다. 수컷 생식소에서 역시 많은 수의 정세포가 관찰되었으며 사정 직후 정자가 빠져나간 부분이 관찰되었다. 이상의 결과 본 종은 초기 성분화 과정에 자성 단계를 거치지 않고 정소와 난소로 분화하는 분화형 자웅이체에 속한다.

• 한국철도학회논문집
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• 제11권2호
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• pp.151-157
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• 2008

디젤엔진 배기가스 저감 장치의 세라믹 필터 재생 특성을 파악하는데 있어서 중요한 인자인 세라믹 필터 내의 온도 분포를 30군데에서 측정하였다. 세라믹 필터 내의 온도 분포에 적합하도록 제작한 K-형 열전대를 사용하여 측정하였다. 5개로 구성된 분할형 전기히터를 장착하고 중심부 전기히터부터 차례로 돌아가면서 ON/OFF 제어를 하면서 세라믹 필터 내의 온도를 측정하였다. 또한 공기 공급 유량을 변화 시키면서 분할형 전기히터의 ON/OFF 제어가 세라믹 필터 내의 온도 분포 특성에 미치는 영향을 연구하였다. 세라믹 필터 내의 온도가 균일한 분포를 가지려면 배기가스저감 장치 입구에서의 유속 분포가 균일한 경우가 유리하였다. 분할형 히터간의 가열 능력 편차에 의해 세라믹 필터 내의 온도 분포도 큰 영향을 받았다.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.82-87
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• 2013

In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.52-57
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• 2005

The increasing automobiles continue to cause air-pollution problem s worse than ever. In fact, many automobile research are involved in how to reduce exhaust emissions effectively specially in $NO_X$ and PM to comply with stringent emission standards, Euro V. This research emphasized on the development of continuous regeneration DPF technology which was one of promising removing technology of particulate matters because of its comparability and high applicability. In addition, this research discussed on some design points of view through correlation study by com paring the experimental data with computational results by the introduction of commercial codes such as CFD-ACE+ and KIVA-3V. The numerical simulation on the performance of continuous regeneration DPF apparatus and corresponding emission characteristics has been predicted well enough and verified with experimental results. The pressure and average temperatures are decreased to about 2.6% and 1.4% respectively under a full engine load condition mainly due to back pressures raised by diesel particulate filter. Pressure, temperature and heat releasing rates tend to decrease specially at higher engine load, but they are not affected at lower engine load regions.

• 한국자동차공학회논문집
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• 제24권4호
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• pp.454-462
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• 2016

This study was conducted in order to estimate the exhaust emissions analysis method of the real driving emission(RDE). The Association for Emissions Control by Catalyst(AECC) has developed a test procedure by using a random cycle method based on the chassis dynamometer. In order to confirm this approach in Korea, Euro 5(DPF), Euro 6(DPF + LNT), and Euro 6(DPF + SCR) were performed on three different vehicles to determine the exhaust gas characteristics of the random cycle, real-road driving test(PEMS), and emission certification driving mode(NEDC). Six different random cycle driving modes were generated by the vehicle specifications(e.g. curb weight, engine power, gear ratio, and maximum acceleration). The NOx emissions were increased in the NEDC, random cycle, and PEMS order in this study regardless of the test vehicles. The random cycle method has the advantage because it utilizes a chassis dynamometer in the laboratories for a repeatable data collection, and it allows any eminent emission improvement checked prior to a real-road driving test with PEMS.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.92-99
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• 2011

To measure the traffic pollutants with high temporal and spatial resolution under real conditions, a mobile emission laboratory (MEL) was designed. The equipment of the mini-van provides gas phase measurements of CO, NOx, $CO_2$, THC (Total hydrocarbon) and number density & size distribution measurements of fine and ultra-fine particles by a fast mobility particle sizer (FMPS) and a condensation particle counter (CPC). The inlet sampling port above the bumper enables the chasing of different type of vehicles. This paper introduces the technical details of the MEL and presents data from the car chasing experiment of diesel bus equipped with aftertreatment system. The dilution ratio was calculated by the ratio of ambient NOx and tail-pipe NOx. Most particles from the diesel bus were counted under 300 nm and the peak concentration of the particles was located between 30 and 60 nm. The total PM number emission from diesel bus equipped with DPF was 10 orders of magnitude lower compared to those emitted from base diesel bus. And the total PM number emission from diesel bus equipped with SCR was comparable to the particle emission from base diesel bus.