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Optimization of Cooling Air Duct and Dust Cover Shape for Brake Disc Best Cooling Performance

Yonsei Univ.-Hoon Kim, Woochul Kim
Hyundai Motor Co.-ByeongUk Jeong, Sang Do Kwak
Published 2014-09-28 by SAE International in United States
Owing to the enhanced performance of engines these days, more heat should be dissipated in the braking system. Failure of doing this properly causes temperature rise in the brake disc which result in the brake fade, disc distortion, brake judder, etc. A cooling-air-duct was proposed as a solution to prevent these from happening. In this paper, we present our work based on experiments optimized parameters such as direction, location, shapes and the size of the duct for the cooling-air-duct installation in real cars. We installed the duct extended from a front bumper to a rear wheel guard. Experimental parameters were compared with theoretical analysis using the impinging jet analysis. The heat transfer coefficients were determined by using the finite elements method (FEM). We found that our experimental data is supportive of theoretical analysis. We believe that our results should serve an useful guideline for designing the cooling-air-duct for braking system.
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An Experimental Investigation on Low Temperature CDPF Regeneration Utilizing Hydrogen

Yonsei Univ.-Kwangmin Chun, Soonho Song
ALANTUM Corporation-Zhijin Liu
Published 2013-03-25 by SAE International in United States
Soot particles accumulated in a DPF should be removed after a certain service time due to high pressure drop. The most common method is oxygen active regeneration which sometimes DPF cracking or melting. In this study, the authors aim to investigate the low temperature regeneration with hydrogen, which could prolong the DPF lifespan and facilitate CDPF regeneration efficiency. The DPF used in this research was coated with Pt/Al₂O₃ 25 g/ft₃ and all experiments were performed on engine test bench. Results showed that DPF regeneration can be realized at about 150°C or even lower. During regeneration, the inside temperature at front part (about 20 mm) of DPF was about 40°C higher than the other parts during regeneration. The maximum inside temperatures during regeneration depend only on the hydrogen concentration and soot oxidation can be calculated simply from the Arrhenius equation using the experimental temperatures.
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Analysis of Factors Affecting Severity of Frontal Motor Vehicle Collision~Prospective Observational Study

Yonsei Univ.-Kang Hyun Lee
Hongik Univ.-Hyung Yun Choi
  • Technical Paper
  • 2012-08-0066
Published 2012-05-23 by Society of Automotive Engineers of Japan in Japan
This study analyzed multiple factors affecting occupant's injury severity at frontal motor vehicle collision by taking the comparison of cases with minor and major injuries. We collected detailed information of 112 injured occupants in 93 accident vehicles with whose AIS were over 2 point in any body part among those who visited at emergency room of two domestic hospitals by frontal motor vehicle crash accident. We also surveyed the cause of accident, information of accident vehicle, vehicle's damage type or extent, occupant's information and injury details, and accident environment. Multivariate logistic regression models were built to adjust for confounders.
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Evaluation of SOF Effects on Deposit Characteristics of the EGR Cooler Using a PM Generator

Yonsei Univ.-Youngbok Lee, Kwang Seok Hong, Soonho Song, Kwang Min Chun
GM Daewoo Auto & Technology-Sunki Min, Doyoung Chung
Published 2011-04-12 by SAE International in United States
The high concentration of particulate matter (PM) in diesel exhaust gas causes significant soot deposition on the wall of EGR cooler, and reduces the heat transfer performance of the EGR cooler and the reduction rate of NOx. The deposition of PM tends to be occurred more severely with "heavy wet PM," which is more frequently at the LTC (low temperature combustion) engine.The objective of this work is to evaluate the effects of soluble organic fraction (SOF) on deposit characteristics of the EGR cooler. To measure reliable mean particle concentration values and surrogate SOFs, the soot generator with SOF vaporizer was used.As for two surrogate SOFs, n-dodecane and diesel lube oil, deposit mass increased when they were injected. Especially from the experiment results, it was found that the lube oil effect was more significant than the n-dodecane effect and lube oil also had a stronger effect on reduction of thermal conductivity by filling pores in deposits. In detail, when diesel lube oil was injected, the deposit mass per unit area increased 121% compared to dry soot…
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Hydrogen Effect on the DeNOX Efficiency Enhancement of Fresh and Aged Ag/Al2O3 HC-SCR in a Diesel Engine Exhaust

Yonsei Univ.-Kwang Min Chun, Soonho Song, Hyerim Gu
GMDAT-Kihong Kim
Published 2011-04-12 by SAE International in United States
HC-SCR is more convenient when compared to urea-SCR, since for HC-SCR, diesel fuel can be used as the reductant which is already available onboard the vehicle. However, the DeNOX efficiency for HC-SCR is lower than that of urea-SCR in both low and high temperature windows. In an attempt to improve the DeNOX efficiency of HC-SCR, the effect of hydrogen were evaluated for the fresh and aged catalyst over 2 wt.% Ag/Al₂O₃ using a Euro-4 diesel engine.In this engine bench test, diesel fuel as the reductant was injected directly into the exhaust gas stream and the hydrogen was supplied from a hydrogen bomb. The engine was operated at 2,500 rpm and BMEP 4 bar. The engine-out NOX was around 180 ppm-200 ppm. H₂/NOX and HC₁/NOX ratios were 5, 10, 20, and 3, 6, 9, respectively. The HC-SCR inlet exhaust gas temperatures were around 215°C, 245°C, and 275°C. The catalyst volumes used in this test were 2.5L and 5L for both fresh and aged catalysts.The DeNOX efficiency of the 5L fresh catalyst was in the range of…
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Low Temperature Active Regeneration of Soot Using Hydrogen in a Multi-Channel Catalyzed DPF

Yonsei Univ.-Kun chul Park, Soonho Song, Kwang min Chun
Published 2010-04-12 by SAE International in United States
Diesel particulate filter (DPF) systems are being used to reduce the particulate matter emissions of diesel vehicles. The DPF should be regenerated after certain driving hours or distance to eliminate soot in the filter. The most widely used method is active regeneration with oxygen at 550~650°C. Fuel penalty occurs when the exhaust gas temperature is increased. The low temperature oxidation technique is needed to reduce fuel consumption.In this study, we found that hydrogen could be used to decrease the PM oxidation temperature significantly on a catalyzed DPF (CDPF). The oxidation characteristics of PM with hydrogen supplied to CDPF were studied using a partial flow system. The partial flow system was used to control temperature and a flow rate independently. The CDPF was coated with Pt/Al₂O₃ 25g/ft₃, and a multi-channel CDPF (MC CDPF) with a square cross section of 1.65 cm width and length of 10 cm was used.Firstly, a hydrogen oxidation was tested for DPFs with and without a catalyst. The oxygen concentration was fixed at 10%, and hydrogen concentration was changed from 2% to…
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Unified Modelling and Simulation of DOC, DPF and Urea-SCR Processes for Diesel Emission Aftertreatment

Yonsei Univ.-Seung-chai Jung, Woong-sup Yoon
  • Technical Paper
  • 2007-08-0108
Published 2007-05-23 by Society of Automotive Engineers of Japan in Japan
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 interest 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. Results show that conversion efficiency of the NOx is varied with NO2 fraction in NOx. In a DOC-DPF-Urea SCR system in an intermediate temperature range, NOx reduction is further activated at higher space velocities.
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A Study on Laser-Induced Incandescence Analysis Method for the Measurement of Primary Particle Size and Concentration of PM in Diesel Exhaust

Yonsei Univ.-Jong-Il Park, Soonho Song, Jaewon Hahn, Kwangmin Chun
  • Technical Paper
  • 2006-05-0271
Published 2006-10-22 by Society of Automotive Engineers of Japan in Japan
In order to investigate forming processes and reducing techniques of ultra-fine particles generated in diesel engine, reliable measurement tools should be developed. Laser-induced incandescence (LII) has emerged as a promising technique for measuring both primary particle size and PM concentration. In this study, time-resolved LII method is applied to diesel engine exhaust for the measurement of primary particles size. A simple formulation is developed to relate particle size with time-resolved LII signal. The data from time-resolved LII experiments are calibrated using Transmission Electron Microscope photograph for all the experimental conditions to investigate the difference between two measurements. The averaged difference for all the experiments is less than 4%.For the measurement of PM concentration in diesel exhaust, the peak LII signal normalized by laser fluence is correlated with PM concentration qualitatively and calibrated using laser extinction method to obtain the absolute PM concentration.

3D Vision System for the Recognition of Free Parking Site Location

Yonsei Univ.-Jai Hie Kim
MANDO Corp.-Ho Gi Jung, Dong Suk Kim, Pal Joo Yoon
  • Technical Paper
  • 2005-03-0189
Published 2005-08-22 by Society of Automotive Engineers of Korea in South Korea
This paper describes a novel stereo-vision-based localization of free parking site, which recognizes the target position of automatic parking system. Pixel structure classification and feature-based stereo matching extract the 3D information of parking site in real time. The pixel structure represents intensity configuration around a pixel and the feature-based stereo matching uses step-by-step investigation strategy to reduce computational load. This paper considers only parking site divided by marking, which is generally drawn according to relevant standards. Parking site marking is separated by plane surface constraint and is transformed into bird's eye view, on which template matching is performed to determine the location of parking site. Obstacle depth map, which is generated from the disparity of adjacent vehicles, can be used as the guideline of template matching by limiting search range and orientation. Proposed method using both the obstacle depth map and the bird's eye view of parking site marking increases operation speed and robustness to visual noise by effectively limiting search range.

PEMFC Operation With Methanol Reforming Process

Yonsei Univ.-Jong-Man Park, Hyun-Jong Kim, Yong-Gun Shul, Haksoo Han
Korea Automotive Technology Institute-Seung-Eul Yoo
  • Technical Paper
  • 2005-03-0205
Published 2005-08-22 by Society of Automotive Engineers of Korea in South Korea
Most of studies for on-board hydrogen production for fuel cells are based on two types of carbon compounds. One is oxygen-containing compounds, methanol, ethanol and etc. The others are hydrocarbons such as ethers (dimethyl ether, etc.), natural gas, propane gas, gasoline, jet fuel and diesel fuel. Automotive Polymer Electrolyte Membrane Fuel Cell (PEMFC) requires hydrogen gas to operate. The most convenient way to obtain the gas would be to use an on-board fuel processor to convert or reform commonly available liquid fuels, such as gasoline, methanol, and ethanol, into hydrogen. In this study, methanol is used as hydrogen source which is also convenient for production, transportation and storage. PEMFC with methanol fuel process system, which is mainly composed of two parts, methanol reforming reaction and preferential oxidation (PROX), has been evaluated to study the enhancing stability of the system.