• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.179-189
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• 1997

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now studied actively. In this study, a transient one-dimensional model developed to simulate the thermal and conversion characteristics of adiabatic monolithic converters operating under warm up conditions is presented. This model takes into account the gas solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. The model has been used to analyze the transient response of an axisymmetric catalytic converter during a warm-up as a function of catalyst design parameters and operation conditions in order to observe their effects on the lightoff behaviour. The experimental test was carried out 2400 cc light diesel engine with DOC.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.5
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• pp.411-417
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• 2002

The purpose of this study is to evaluate the emission reduction characteristics depending on the formation of the catalyst which influences the development of the diesel oxidation catalyst (DOC) suitable for small-sized diesel engines. We also attempted to suggest the feasibility of it as an after-treatment device. The reduction efficiency of DOC for CO and HC was proportional to the contents of precious metals, and the particulate matter (PM) has been reduced as much as 53∼59%. The reduction rate of soluble organic fraction (SOF) by DOC attachment revealed 100%. The composition of sulfate in PM increased from 3%, 7∼11% by installation of DOC. It is described that increase of sulfate contributed to the production of PM. This result also showed that the SOF and sulfate have trade-off relationship.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.13-18
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• 1999

Recently among after-treatment devices which have high possibility of utility diesel oxidation catalyst(DOC) is concerned over the world. DOC oxidizes pollutants by means of activate-reaction during by-passing in the catalyst in doing so conversion efficiency of PM, CO and HC is high and this device does not have an effect on engine performance because back pressure is not nearly increased, But as a small amount of sulfur content in fuel is oxidized it makes sulfate which is absorbed on the surface of catalyst. So in this study the experiment is carried out by means of using ordinary fuel(0.1wt%) and low sulfur fuel(0.05wt%) with DOC and the emission gas of diesel engine is measured.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.34-42
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• 1999

In late 1997, the portion of registered light-duty diesel vehicle was 25.3% and its emission rate was 17.1% in Korea. Especially, diesel particulate matters(DPM) and NOx are hazardous air pollutants to human health and environment in urban area. The reduction technologies of exhaust emissions from diesel engines are improvement of engine combustion, fuel quality and development of diesel exhaust after treatment , In this study , a light-duty diesel oxidation catalyst(DOC) that is one of the diesel exhaust after treatment was made for performance evaluation and the emission characteristics were tested on CVS-75 mode. And the analysis of the particle size distribution with scanning mobility particle 100, 67.6% and 66.7, 10.0% for Pt and Pt-V catalyst .And for Pt catalyst, the PM increased 7.8% because of increasing sulfate but Pt-V catalyst reduced the PM to 23.0% . Test results of particle size distribution showed that peak values of number and mass densities are respectively 100∼200nm their distribution trend independent of vehicle speed.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.13-21
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• 2001

Diesel emission control is being addressed worldwide to help preserve the global environment. This paper mainly deals with the effects of oxidation catalysts to reduce emissions from the automotive heavy-duty diesel engine. Two types of the oxidation catalyst with different kinds of precious material were used. An 11 litter displacement diesel engine with turbocharger was operated to evaluate DOC with various engine speed, load conditions under D-13 mode cycle. We could propose the detail emission data of an automotive heavy-duty diesel engine and the characteristics of the conversion efficiency of the DOC under the D-13 mode. It was found that the mean conversion efficiencies of CO and THC were 49.7% and 61% under the D-13 mode test, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.443-454
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• 1998

Pt-V catalytic converter was installed on a heavy duty diesel engine and the characteristics of the emission reduction were tested using a engine dynamometer at various operating conditions. The emission reduction performance of Pt-V catalyst was also compared with that of a commercialized Pt catalyst currently being used in some of the heavy duty diesel engines in advanced countries. The effects of Pt-V and Pt catalysts on regulated and unregulated emissions were investigated using a 0.05 weight percent sulfur content fuel with an engine dynamometer Experiments for gaseous emissions (CO, HC and aldehyde) as well as particulate emissions (TPM, SOF and sulfate) have been conducted at several operating conditions such as T-7 mode, D-13 mode and S-13 mode before and after installing the Pt-V and Pt catalysts in the exhaust system. The emission reduction performance of Pt catalyst with respect to CO, HC, SOF, PAHs and aldehyde was found to be a little higher than that of Pt-V catalyst, but the Pt catalyst showed innate disadvantage of causing an increase of PM due to the sulfate formation via high SO2 conversion at high exhaust temperature, especially above 45$0^{\circ}C$.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.59-64
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• 2003

Recently, as people pay attention to the environmental pollution, the emissions of diesel engine have been a serious problem. We carried out the performance evaluation test of Diesel Oxidation Catalysts (DOC) for HSDI diesel engine equipped vehicles. The DOC, basically coated with Pt catalyst, was manufactured with various washcoat materials. It was found that CO conversion efficiency depends on temperature, but THC conversion efficiency is dominated by temperature and space velocity. The THC and CO conversion efficiencies of aged catalysts were increased with additions of $ZrO_2$ and zeolite B in the washcoat. We found that DOC performance changes with coating techniques, even through it has same washcoat materials. The DOC coated by high temperature washcoat coating technology showed good conversion efficiency than low temperature washcoat coated DOC.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.37-38
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• 2012

Two catalyst systems with different content of precious metal coated on DOC are carefully tested in a diesel engine to investigate the emission characteristics of $NO_2$. Three types of experiment methods ($NO_2$ conversion test, ETC mode test, and BPT test) are applied to compare the performance of the two catalyst systems. All the experimental results consistently indicate that it is possible to satisfy $NO_x$ regulation by properly lowering the content of precious metal without the loss of PM removal performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.138-142
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• 1998

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects of low sulfur diesel fuel in heavy duty diesel engine equipped with DOC. We tested to estimate change of engine performance for the low and high sulfur diesel fuels in a 11,000cc diesel engine equipped with DOC. We conducted test to estimate the reduction efficiency of exhaust gas in D-13 mode of heavy duty diesel regulation mode and in smoke opacity mode for two samples of high sulfur content (0.2%) and low sulfur content(0.05%)