• Transactions of the Korean hydrogen and new energy society
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• v.31 no.6
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• pp.614-621
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• 2020

Recently, as the fine dust is increased and the emission regulations of diesel engines are strengthened, interest in diesel soot filtration devices is rapidly increased. In particular, there is a demand for technology development for higher efficiency of diesel exhaust gas after-treatment devices. As part of this, many studies conducted to increase the exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the DPF and reducing the pressure drop between the inlet and outlet of disel particle filter (DPF). In this study, computational fluid dynamics (CFD) simulation was performed when exhaust gas flows into the canning reduction device equipped with a 13" asymmetric DPF in order to maintain the flow uniformity in the diesel exhaust system and reduce the pressure. In particular, a study was conducted to find the geometry with the smallest pressure drop and the highest flow uniformity by simulating the DPF I/O ratio, exhaust gas temperature, inlet-outlet pressure and flow uniformity according to the geometry and hole size of distributor.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.167-176
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• 2003

This study is focused on the development of a new muffler. A control valve installed in the exhaust system is operated by torsion springs, and its open angle is controlled automatically corresponding to the engine operating conditions. A control valve and a control muffler sensing exhaust-gas pressure are made f3r developing a new muffler. The experiments were done using an exhaust system simulator having the same pulsation wave frequency and similar pulsation propagation characteristics of a real exhaust system. The purpose of this study is to develope a new muffler system which has improved noise reduction quality and less power loss than conventional mufflers and electronic-control mufflers. Finally the characteristic of noise compared with conventional muffler and muffler sensing exhuast-gas pressure.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.60-64
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• 2000

An experimental study was performed to investigate the optimal ejector and operating condition of vessel incinerator. Exhaust gas temperature and secondary air which makes vacuum pressure at ejector throat regions were considered as an important factor. According to the measurement of pressure temperature and nitrogen oxides between non combustion and combustion we found the stream and exhaust gas characteristics of incinerator. This results can give us the exhaust gas temperature control system air pollutant reduction method and the optimum ejector design.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.148-156
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• 2001

Computational Fluid Dynamics (CFD) analysis was carried out to investigate exhaust gas flow and acoustic characteristics in the exhaust system of a passenger car. Transient 3-dimensional flow field in the front and rear mufflers was simulated by CFD and far-field sound pressure was modeled by a simple monopole source method. Engine performance simulation was also performed to obtain the boundary condition of instantaneous fluid flow variation at the inlet of the exhaust system. Detailed exhaust gas flow characteristics such as velocity and pressure distribution inside the mufflers were presented and the pulsating pressure amplitude was compared at several positions in the exhaust system to deduce sound pressure level. The present method of the acoustic analysis coupled with CFD techniques would be very effective for the prediction of sound noise from vehicle exhaust systems although the effects of the inlet boundary condition and heat transfer on the accuracy of the prediction have to be validated through further studies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.217-222
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• 2006

Internal combustion engine is the main source of environmental pollutants and therefore advanced technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, when the exhaust gas is released front the automotive muffler, exhaust noise has many bad influence on the surrounding environment. In order to reduce the exhaust noise, it is necessary that automotive muffler must be designed for best exhaust efficiency. The sound insulation room was installed for the analysis of an acoustics characteristics of the noise from automotive muffler, in this study. Exhaust gas noise, noise distribution characteristics, pressure and temperature of exhaust gas were investigated with the change of annulus temperature of air cooled annulus automotive muffler and cooled annulus automotive muffler. The following results were obtained with this study. From the frequency analysis of automotive muffler, high noise distribution was observed in the range $100{\sim}2000Hz$. It means that the noise in this range has an dominate influence for the overall noise. Noise reduction of automotive muffler was affected by the temperature of annulus. It is caused the result that the high temperature and pressure of exhaust gas are changed lower by the drop of annulus temperature. The tendencies of noise, the temperature and pressure of exhaust gas are similar to the performance curve of engine. Exhaust gas pressure is determined by the r.p.m. of engine and affected by the cooling performance of automotive muffler.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.892-898
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• 2000

This study is on the development of a new muffler composed of a valve system using an elasticity or spring. The valve system using the elasticity of spring is set along the exhaust-gas flow and designed to work itself alone the driving condition of a engine. By that reason the engine capacity is so enlarged that a muffler with controller sensing exhaust-gas pressure is able to be satisfied to noise reduction and- power enlargement more than conventional muffler. The purpose of this study is to develope the new muffler which has more noise reduction and power enlargement than conventional muffler and electric-control muffler.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.491-502
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• 1997

This paper describes a theoretical and exprimental investigation of the pressure - time histories of some basic internal combustion engine exhaust systems. The program package is utilized the method of characteristics to solve the general equations of one - dimensional unsteady gas flow. This analysis is then combined with boundary models, based on quasi - steady flow approach, to give a complete treatment of the flow behavior in the exhaust system. Using a rotary valve exhaust simulator, experimental pressure - time histories were obtained. The predictions are com¬pared with measured results and show a high degree of correlation in amplitude and phasing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.15-20
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• 2018

The objective of this study is to numerically investigate the thermal characteristics of an automobile exhaust-based heat exchanger for automotive thermoelectric power generation with various exhaust gas mass flow rates and temperatures. The heat exchanger for automotive thermoelectric power generation has a square-type pin installed inside, so the maximum amount of heat can be transferred to the thermoelectric element from the heat energy coming from the automobile exhaust gas. The exhaust gas mass flow rate changed from 0.01, to 0.02, to 0.03 kg/s, and the exhaust gas temperature changed from 400, to 450, to 500, to 550, to $600^{\circ}C$, respectively. A numerical simulation was conducted by using the commercial program ANSYS CFX v17.0. Consequently, the exhaust gas pressure difference between the inlet and the outlet of the heat exchanger is determined according to the flow rate of the exhaust gas. When the mass flow rate of the exhaust gas increased, the pressure difference between the inlet and the outlet of the heat exchanger increased, but the exhaust gas pressure difference between the inlet of the heat exchanger and the outlet did not vary with the exhaust gas temperature. Therefore, in order to obtain the maximum surface temperature from the heat exchanger, the exhaust gas mass flow rate should be lower, and the exhaust gas temperature should be higher.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.15-22
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• 2014

Multiple devices have been installed to reduce exhaust emissions and to increase thermal efficiency. Those devices reduce the exhaust pipe opening area and increase the exhaust gas pressure. The pressure increase disturbs a gas flow and has a bad effect on the engine performance. However there is some study that NOx can be reduced with exhaust gas pressure increase. In this study an engine performance is tested with various opening ratios. The result shows that the fuel consumption rate is reduced in case of little amount of the pressure increase, and NOx is reduced with the pressure increase, while the concentration of the toxic exhaust gases are increased in the case of high back-pressure.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.80-86
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• 2017

In this paper, it is proposed to solve the problem of the harmful exhaust gas reduction device DPF. The exhaust gas is effectively guided through the control of the exhaust gas flow path which is separated in both directions. Through cross control of two DPF units, it helps to improve the purification and regeneration combustion characteristics of harmful emissions. It is possible to prevent an increase in internal pressure caused by deposition of particulate matter in the DPF. It is also an object of the present invention to provide an automobile harmful exhaust gas reduction device capable of solving the problem of lowering the output and lowering the fuel consumption.