• 한국자동차공학회논문집
• /
• 제7권7호
• /
• pp.113-121
• /
• 1999

Diesel particulate matter is known to be one of the major harmful emissions produced by diesel engines. Diesel particulates are subject to diesel emission regulations and have lately become the focus in the diesel emission control technology. Thus, the aftertreatment system is adopted at the diesel engine exhaust to reduce the particulate emission. Although this benefit is recognized, it is not clear how the aftertreatment system influences quantitatively the particle size distribution distribution. In this study, the particle size distributions of diesel exhaust were measured using the scanning mobility particle sizer with and without the aftertreatment system. There results showed that the diesel particulate filter and plasm system reduced the number of emitted particles by more than 90% and about 80% respectivley in the particle size range of 20nm∼600nm. On the other hand no significant effect of the diesel oxidation catalyst on the particle number concentration was detected.

• 한국자동차공학회논문집
• /
• 제15권4호
• /
• pp.178-185
• /
• 2007

A study is improvement of power and emission in a inline-pump Dr diesel engine by using Dimethyl ether Fuel. Dimethyl ether (DME) is an oxygenated fuel with a cetane number higher than that of diesel oil. It meets the ULEV emission regulation and reduces the smoke to almost zero when used in a diesel engine. But NOx emission is almost same and CO, THC emissions are lower than that of diesel engine. The emissions aren't satisfied the stronger emission regulation in the further. Generally DOC (Diesel Oxidation Catalyst) is used to reduce CO & THC emissions and EGR (Exhaust Gas Recirculation) system is used to reduce NOx emission. Test results showed that the torque and the power with DME were almost same as those of pure diesel oil, but the brake thermal efficiency increased a little. also the BSEC (Brake Specific Energy Consumption) with DME was similar that of diesel. The test results showed that the DOC was the vary effective method to reduce the CO emission in case of Dimethyl Ether Fuel in diesel engine. But, THC emission is showed a little reduction rates. Also EGR system was the very effective method to reduce the NOx emission in case of Dimethyl Ether Fuel in diesel engine.

• 한국자동차공학회논문집
• /
• 제24권2호
• /
• pp.152-160
• /
• 2016

The market demand for diesel engine tends to increase in general passenger cars as well as commercial vehicles because of its advantages. However, to meet the vehicle emissions regulation which will be more stringent in the future, it is necessary to plurally apply all after-treatment technologies such as diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF), lean NOx trap (LNT) and selective catalytic reduction (SCR), and so on. Accordingly, the exhaust after-treatment system for diesel vehicle requires the technology of minimizing the numbers of catalysts by integrating every individual catalysts. The purposes of this study is to develop hybrid exhaust after-treatment device system which simultaneously uses LNT/DPF and SCR/DPF catalyst concurrently reducing NOx and particulate matter (PM). As the results, the hybrid system with $NH_3$ generated at LNT/DPF working as a reducing agent of SCR/DPF catalyst, improving NOx conversion rate, was found to be more excellent in de-NOx performance than that in LNT/DPF alone system.

• 동력기계공학회지
• /
• 제12권5호
• /
• pp.34-39
• /
• 2008

The combustion purpose of diesel engine is to reduce the emission of green gas and to produce high output. Generally, the regulation matter of emission gas is largely diveded by 'THC', 'NOx', 'CO' and 'PM'. Among those matters, the most problem is to disgorge into 'PM', the character of diesel combustion. Diesel PM can be controlled using Diesel Particulate Filter, which can effectively reduce the level of soot emissions to ambient background levels. $NO_2$ generated by the DOC is used to combust the carbon collected in the DPF at low temperature. To certificate DPF device that is suitable to domestic circumstances, it is necessary to exactly evaluate the DPF devices according to the regulation of DPF certificate test procedure fur retrofit. To do carry out the above-mentioned description the understanding of that regulation like the standard of PM reduction is needed. In this study the test procedure including test cycle and BPT test condition was examined, and also the test result for specific DPF was analyzed. In every test like field test, PM reduction efficiency test and Seoul-10 mode test, no defect was showed.

• International Journal of Automotive Technology
• /
• 제8권1호
• /
• pp.27-31
• /
• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Therefore, the present study evaluates the effect of fuel injection characteristics on regeneration performance in a DOC and a catalyzed CR-DPF system. The temperature distribution on the rear surface of the DOC and the exhaust gas emission were analyzed in accordance with fuel injection strategies and engine operating conditions. A temperature increase more than BPT of DPF system was obtained with a small amount fuel injection although the exhaust gas temperature was low and flow rate was high. This increase of temperature at the DPF inlet cause PM to oxidize completely by oxygen. In the case of multi-step injection, the abrupt temperature changes of DOC inlet didn't occur and THC slip also could not be observed. However, in the case of pulse type injection, the abrupt injection of much fuel results in the decrease of DOC inlet temperatures and the instantaneous slip of THC was observed.

• 한국자동차공학회논문집
• /
• 제13권3호
• /
• pp.80-86
• /
• 2005

In this study, we investigated the characteristics of the conversion efficiency and the effect of ageing Diesel Oxidation Catalyst (DOC). The DOC was composed of Warm-up Catalytic Converter (WCC) and Underbody Catalytic Converter (UCC). As the result, the conversion efficiency of THC was 10$\~$50$\%$ on WCC and 30$\~$40$\%$ on UCC .The conversion efficiency of CO was 80$\~$90$\%$ on WCC and remained 10$\~$20$\%$ of CO was purified on UCC. The WCC shows high conversion efficiency on CO. After 20 hours aging process of engine bench, conversion efficiencies of THC and CO were improved a little, because it was activated catalyst surface by 20 hours aging. In case of 80 hours aging, the conversion efficiencies of THC and CO were decreased on WCC. However, the UCC was not affected by aging process .

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
• /
• pp.98-103
• /
• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Temperature, gas compostion and flow rate of exhaust gas are important parameters in DPF evaluation, especially regeneration process. Engine dynamometer and degment tester are generally used in DPF evaluation so far. But these test method couldn't reveal the effect of various parameters on real DPF, such as O2 concentration, amount of soot and exhaust gas temperature. This research has studied the possibility using dump combustor that used to take an approach lean premixed combustion in gas turbine for a DPF power and optimized. It is possible that utilize the system as DOC (Diesel Oxidation Catalyst) and SCR(Selective Catalytic Reduction) assessments test as well as DPF evaluation

• 한국산학기술학회논문지
• /
• 제7권3호
• /
• pp.278-284
• /
• 2006

가솔린 엔진에 비하여 디젤 엔진은 효율성, 신뢰성, 내구성 측면에서 우수한 특성을 보유하고 있다. 그러나, 디젤 엔진의 최대 약점은 카본기 물질로 알려진 분진(PM)의 방출이다. 최근 엔진 제어와 후처리를 통하여 엄격한 규제 조항에 부합하는 커다란 기술적 발전을 이룩하였다. 보다 엄격하게 진행되고 있는 환경규제를 대응하기 위하여, 본 연구에서는 배기가스 온도 증대를 통한 PM 저감 방안에 초점을 맞추었다. PM 재생 온도를 증대시키기 위하여, DPF 필터와 DOC 전방에 HC를 분사하는 방안을 제안하였다. 본 연구를 통하여, 우리는 LPG 분사 특성을 파악할 수 있는 벤치를 제작하고 관련 DB를 구축하여 LPG 분사 최적화와 ECU 제어 로직을 정량화 할 수 있었다.

• 청정기술
• /
• 제26권1호
• /
• pp.22-29
• /
• 2020

최근 미세먼지 증가로 인하여 디젤엔진의 배출 규제가 강화됨에 따라 디젤 매연여과장치에 관심이 급증하게 되었으며, 특히 디젤 배기가스 후처리 장치의 고효율화에 대한 기술개발이 더욱 요구되고 있다. 이에 대한 일환으로서 디젤매연여과장치(diesel particulate filter, DPF) 내 배기가스의 유동 균일도를 향상시키고 배압을 낮추어서 배기가스처리 효율을 높이는 연구가 많이 되고 있다. 본 연구에서는 ANSYS Fluent를 이용하여 직경 12"의 DPF와 디젤산화촉매(diesel oxidation catalyst, DOC)를 장착한 디젤 매연여과장치에서의 배기가스의 유속과 온도, DPF IO ratio, Ash와 PM양에 따른 배압에 미치는 영향을 시뮬레이션 하여 배압을 낮추는 최적화 연구를 하였다. 결과로서 배기가스의 온도와 유속이 낮을수록 배압이 낮아졌으며, PM양이 Ash양보다 배압에 더 큰 영향을 주는 것으로 나타냈다. 또한 비대칭 DPF가 대칭 DPF에 비해 배압이 더 낮게 나타냈으나, 유동 균일도의 경우는 다양한 변수에 관계없이 일정하게 나타냈다. european stationary cycle (ESC), european transient cycle (ETC) 조건에서 PM의 정화효율은 비대칭, 대칭 DPF 관계없이 유사하나, particle number (PN)의 정화효율에서는 비대칭 DPF가 대칭 DPF에 비해 높게 나타냈다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제34권4호
• /
• pp.508-514
• /
• 2010

본 논문은 커먼레일 디젤엔진의 정속운전시 배출되는 나노크기의 입자상 물질을 분석하는데 초점을 두었다. 디젤산화촉매 후단에서 나노입자상 물질의 개수농도 저감수준은 크지 않았으나 매연여과장치 후단에서 분석한 결과 1,000배 정도 저감되는 결과를 확인하였다. 고속 고부하 조건에서는 매연여과장치의 자연재생 효과로 인해 입자상 물질은 증가하였다. 연료분사시기를 BTDC $6^{\circ}CA$ 에서 ATDC $4^{\circ}CA$까지 지각시킨 결과 입자상 물질의 개수농도는 감소하였지만 최지각 조건인 ATDC $9^{\circ}CA$에서는 증가하는 결과를 확인하였다. EGR 적용시 핵화모드 입자상 물질은 저감되는 경향을 보였으며 축적모든 입자는 증가하였다.