• Fire Science and Engineering
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• v.31 no.1
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• pp.89-97
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• 2017

This study analyzed the case of diesel car fires that occurred while driving in a tunnel 5 days after maintenance at a car service center. The results of the investigation and analysis found that a large amount of white foreign matter adhered to the inside of the exhaust port and the insulating plate above the DPF (diesel particulate filter) installed in the middle of the exhaust pipe was melted and lost. In particular, the metal floor of the car above the DPF was molten and pierced, and the rubber mat placed on the metal floor was burnt. Moreover, while the exhaust pipe in front of the DPF showed no overheating mark, such a mark was observed in the exhaust pipe from the DPF to the exhaust port. Because these findings may appear only when the DPF is overheated and ignited, this car fire is believed to have been caused by internal overheating of the DPF. The car fire investigation of this study suggests that if white foreign matter is found in the inside of the exhaust port during a fire cause investigation of a diesel car, the cause of the fire should be determined by removing the DPF and examining the internal damage of the DPF.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.479-485
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• 2019

As exhaust gas systems of ships become more complicated, it is necessary to calculate an accurate pressure loss at their design stage. If the dynamic loss coefficients of non-standard fittings mainly used in exhaust gas pipe (EGP) are well-documented, it would be possible to calculate precise pressure loss more readily than using the conventional method that analyzes the entire system. In the case of a ship's EGP, the flow rates and temperatures of exhaust gas are determined by engine specifications, and the range of the flow rate and temperature is limited according to operating conditions. In addition, as it is possible to define non-standard fittings frequently used in an EGP, a database can be easily constructed and effective. This paper illustrates effective parameters and analysis cases of several types of non-standard fittings mounted in ship EGPs. The analysis procedure proposed in this paper is verified using existing research results on HVAC fittings. The numerical procedure, which is minimally affected by manpower and grid, is established such that it can be applied at the industry level.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.27-32
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• 1999

This study identified concentrations of all pollutants emitted from idling of vehicles such as cars, taxis, trucks, and buses. In this investigation we analyzed concentrations of $SO_2$, NOx, CO, and $CO_2$ omitted from exhaust pipe of vehicles as a function of vehicle type, mileage, exhaust volume, and fuel type using the GreenLine. Compact or light cars, which have relatively low exhaust volume, showed much higher exhaust concentrations of $CO_2$, CO, and NOx than those emitted from vehicles with high exhaust volume. Vehicles using light oil showed much higher exhaust NOx concentrations than those of vehicles using gasoline. Vehicles using LPG and compact cars showed very high exhaust CO concentration compared to other vehicles. NOx exhaust concentrations were increased with increasing the mileage of vehicles.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.24-34
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• 1985

The study of unsteady gas exchange processes in the inlet and exhaust systems of the single-cylinder 4-stroke cycle spark ignition engine is presented in this paper. The generalized method of characteristics including friction, heat transfer, change of flow area and entropy gradients was used for solving the equations defining the gas exchange process. The path line calculation was also conducted to allow for calculation of the gas composition and entropy change along the path lines, and of the variable specific heat due to the change of temperature and composition. As the result of the simulation, the properties at each point in the inlet and exhaust pipe, pressure and temperature in the cylinder, and charging efficiency were obtained. Pumping loss and residual gas fraction were also computed. The effect of engine speed, exhaust and inlet pipe length on the pumping loss and charging efficiency were studied showing that the results were in agreement with what has been known from experiments.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.325-331
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• 2003

This paper described the characteristics of the exhaust pressure and proposed the assistant device for detection of misfired cylinder. Misfire, one of abnormal combustion, affects a bad influence of the 3-way catalyst and emits unburned hydrocarbon. Therefore, to prevent these unusual phenomena and eliminate the factor of the environmental pollution, early detection and correction of the misfired cylinder play a very important role. The configuration of assistant device was changed by length and diameter of pipe and analyzed with the install position on the exhaust system. Experimental results showed that the configuration of assistant device is not affected more than length and diameter of pipe and the assistant device is be effective in the detection of misfired cylinder on the gasoline engine.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.1
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• pp.1-9
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• 2000

The goals of this research are to understand the $NO_x$ emission in direct injected diesel engine with premixed hydrogen fuel. Hydrogen fuel was supplied into the test engine through the intake pipe. Amount of hydrogen-supplemented fuel was 70 percent basis heating value of the total fuel. The effects of exhaust gas recirculation(EGR) on $NO_x$ emission were studied. The exhaust gas was recirculated to the intake manifold and the amount of exhaust gas was controlled by the valve. The major conclusions of this work include: (i) the tested engine was run without backfire under 70 percent hydrogen fuel supplemented; (ii) the peak cylinder pressure was decreased with increase of EGR ratio due to the decrease of oxygen concentration in an intake pipe; and (iii) $NO_x$ emission was decreased by 77% with 30% EGR ratio. Therefore, it may be concluded that EGR is effective method to lower $NO_x$ emission in hydrogen fueled diesel engine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.373-378
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• 2000

Recently, it has been important to develop light, silent and less-vibrational automobile. In this study, in order to investigate the characteristics of the noise caused by the main silencer components-stiffener flange, inlet pipe and exhaust pipe etc., computational flow analysis, vibration and noise experiments were performed about the variable heights of the stiffener flange. Flow structure in the mainsilencer which calculated by CFD solver-IDEAS ESC, and frequency response function results of impact hammer test was proposed and it was found good agreement between former results and the exhaust orifice noise measured.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.251-257
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• 1998

Active mufflers have been mainly applied in the large industrial engine due to considerable expense for implementation, but a necessity of development has been increased by the tightened regulation of exhaust noise and the request of high power. In this study, the active muffler prototype for installing in an automobile is designed and constructed. The active muffler is designed so that the primary noise and the control sound are propagated as a plane wave in the outlet. Therefore, the error microphone could be placed outside the high temperature centers of the tail pipe, and the noise radiating to the outside could be reduced in the whole areas around the outlet. For evaluating the control performance of the prototype, the control experiments of band-pass filtered random signal and the modulation of sinusoidal signal which are generated from the primary noise speaker as practical exhaust sound level are implemented. And to investigate the radiation pattern from the outlet of tail pipe and the noise reduction level of points placed adjacent to the outlet, the sound level of adjacent points of thirty is measured.

• 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.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.6
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• pp.48-56
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• 1991

This paper describes the experimental investigations on the pressure variations of intake and exhaust manifold and mass flow rate through exhaust turbine of turbocharged 6-cylinder diesel engine. The turbocharger of experimental diesel engine is constructed with the radial ty pe exhaust turbine and blower driven by exhaust gases. The pressure variations were measur ed by pressure transducer at the points such as turbine inlet and outlet, compressor inlet and outlet, and inlet pipe and exhaust manifolds for normal and combined charging engines with the change of engine speed. The experimental results of this study show that the mass flow rate of exhaust turbine and the variations of pressure in intake and exhaust manifold are all increased with the increase of engine speed.