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정승채(Seung-chai Jung),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Diesel oxidation catalyst (DOC) is a widely used device to reduce harmful species of exhaust gas with less engine back pressure. A one-dimensional model simulating the oxidation of CO, HC and NO was developed to predict the state of gaseous emission exiting a DOC. The model formulation is based on the constraint of conservation of mass, species and energy inside DOC. Kinetics of CO, HC and NO were modeled assuming global reaction using inhibition factor. Steady-state experimental data covering a wide range of operating conditions calibrates the model parameters. The results showed good agreement with the experimental data in a test window of 200℃~500℃ for temperature and 0.1㎥/s~0.7㎥/s for volumetric flowrate.
열, 첨가제, 촉매에 의한 DPF내 포집된 입자상 물질 재생 모델링
정승채(Seung-chai Jung),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
DPF reduce particulate emission by physically trapping the particles and the collected PM has to be periodically or continuously removed from the filter by a regeneration process. One of the major issue for DPF system is developing a safe and effective regeneration strategy. In the present study, PM oxidation by heat, fuel additive and catalyzed filter was studied. One-dimensional mathematical models describing regeneration and filtration process were developed. These models can produce spatio-temporal evolution of filter temperature, pressure drop and mass of PM remained in the filter during regeneration. Models are calibrated by measured data and simulation results showed good agreement.
정승채(Seung-chai Jung),박종선(Jong-sun Park),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_1
Prediction of diesel particulate filtration necessitates appropriate models for pressure drop and particulate matter (PM) collection, and the models are not frequently deterministic, thus must be closed with certain parameters of much smaller scales typically determined experimentally. Included are soot cake permeability, soot cake density, soot density in filter wall, and percolation constant. Aiming at elucidating these essential parameters, the present study attempts the enhancement of DPF filtration model with non-linear description of soot cake regression, The model is properly validated with single channel DPF measurements. Effects of these parameters on the pressure drop, a direct measure of filtration quality, are estimates in a parametric manner and discussed in terms of filtration velocity. Conclusively, the extent of percolation constant is controlling pressure drops, and soot density in the filter wall is relatively important in deep-bed filtration regime. Filtration quality of the deep-bed mode is relatively less sensitive to particle size than soot cake regime.
정승채(Seung-chai Jung),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Particulate filter system has been developed to cope with tight diesel PM emission regulations. One of the major issue for DPF system is building a safe and effective regeneration strategy. In the present study, NO₂-assisted regeneration method using DOC was studied. A one-dimensional DOC model simulating oxidation of chemical species was developed to predict the gaseous emission downstream of DOC, especially NO₂ concentration. And this model was incorporated with one-dimensional DPF model simulating particle filtration, pressure drop and PM oxidation to predict filtration and regeneration performance of DOC+DPF system. Mathematical models were calibrated with the controlling parameters obtained from DOC+DPF test.
DOC-DPF-SCR 시스템에 의한 디젤 배기 내 NO<SUB>x</SUB>, 입자상 물질 저감 과정의 일관 모델링 및 성능 예측
정승채(Seung-chai Jung),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Computer methods employing simplified mathematical models with empirically tuned model parameters can be efficiently practiced into an optimization of a diesel aftertreatment system. Components of prime interests are diesel particulate filter, diesel oxidation catalyst and de-NOx catalytic converter. de-NOx, de-PM, and de-HC processes in each member unit are separately modeled, formulated and then combined into an integrated analysis procedure for a unified prediction of the diesel emission aftertreatment. The unified model is empirically tuned and validated with comprehensive engine and laboratory data. Parametric studies to investigate the effects of emission species and space velocity on the NOx and soot reductions are conducted. A lowered NO₂/NO, ratio after PM oxidation in DPF contributes to promote the NOx reduction by SCR at intermediate gas temperatures. In contrast, NOx reduction is inert to the PM oxidation at high temperatures. Rate of PM accumulation appears to be a strong function of temperature and NOx concentration.
정승채(Seung-chai Jung),윤웅섭(Woong-sup Yoon) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Particulate filter system has been developed to cope with tight diesel PM emission regulations. One of the major issue for DPF system is developing safe and effective thermal regeneration strategy because any PM oxidation methods without additional heat source do not ensure lasting permissible back-pressure level under all engine operation condition. In the present study, thermal regeneration process of wall-flow DPF has been studied using one-dimensional model. Regeneration model consists of mass, momentum and energy conservation equation. Heat generation by particulate matter oxidation was modeled through heterogeneous global carbon reaction. This model can produce spatio-temporal evolution of filter temperature, distribution of particulate layer thickness and mass of PM remained in the filter during regeneration. Simulation results were compared to three different experimental data and showed good agreement, therefore this model can be used to develop thermal regeneration strategy.