• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.93-100
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• 2009

Intake/exhaust valve timing and exhaust cam lift were changed to control the internal exhaust gas recirculation (IEGR) and combustion phase of homogeneous charge compression ignition (HCCI) engine. To measure the IEGR rate, in-cylinder gas was sampled during from intake valve close to before ignition start. The lower exhaust cam made shorter valve event than higher exhaust cam and made IEGR increase because of trapping the exhaust gas. IEGR rate was more affected by exhaust valve timing than intake valve timing and increased as exhaust valve timing advanced. In-cylinder pressure was increased near top dead center due to early close of exhaust valve. Ignition timing was more affected by intake valve timing than exhaust valve timing in case of exhaust valve lift 8.4 mm, while ignition timing was affected by both intake and exhaust valve timing in case of exhaust valve 2.5 mm. Burn duration with exhaust valve lift 2.5 mm was longer than other case due to higher IEGR rate. The fuel conversion efficiency with higher exhaust valve lift was higher than that with lower exhaust valve lift. The late exhaust and intake maximum open point (MOP) made the fuel conversion efficiency improve.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.4
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• pp.57-65
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• 1988

The study of unsteady gas exchange processes in the intake and exhaust systems of four-cylinder, four-stroke cycle internal combustion engine is described in this paper. The calculation model for the intake and exhaust systems is established and solved by the characteristic method for the equations defining these systems. A constant pressure theory is used for modeling branches of intake and exhaust manifolds. The relationship between the volumetric efficiency and the intake, exhaust pressure variation is clarified by simulation of these systems. It is found that the volumetric efficiency mainly depends on the intake pressure during the short period before the intake valves is closed, that the volumetric efficiency is influenced a little by intake chamber volume in the intake and exhaust system.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.775-780
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• 2003

In this study, a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold in a single cylinder engine. To get the boundary conditions for a numerical analysis, one dimensional and unsteady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the exhaust pipe diameters to calculate the pulsating flow when the intake and exhaust valves are working. As the results of numerical analysis, the shapes and distributions of the exhaust pipe pressures were influenced strongly on the cylinder pressure. As the exhaust pipe diameter is decreased, the amplitude of exhaust pressure is large and the cylinder pressure was showed low in the region of intake valve opening time.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.75-82
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• 2004

In this research, a computer analysis has been developed for predicting the Pipe pressure of the intake and exhaust manifold in a small single cylinder engine. To get the boundary conditions for a numerical analysis one dimensional and unsteady gas dynamic calculation is performed by using the MOC(Method Of Characteristics). The main numerical parameters are engine revolutions. to calculate the Pulsating flow which the intake and exhaust valves are working. The distributions of the exhaust pipe pressures were influenced strongly to the cylinder pressures and the shapes of exhaust pressure variation were similar to the Inside of cylinder pressure As the engine revolutions are increased. the intake pressure was lower than ambient pressure. The amplitude of exhaust pressure had increased and the phase of cylinder pressure $P_c$ is delayed and the amplitude of cylinder pressure were increased.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.315-331
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• 2004

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle. four-cylinder. swirl chamber type. water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas Recirculation (EGR) control system for reducing $\textrm{NO}_{x}$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $\textrm{NO}_{x}$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection. however. would be included within those of scrubber EGR system. In order to survey the effects of cooled EGR and moisture on $\textrm{NO}_{x}$ and soot emissions. the intake mixtures of fresh air and recirculated exhaust gas are heated up using a heater with five heating coils equipped in a steel drum. It is found that intake and exhaust oxygen concentrations are decreased, especially at higher loads. as EGR rate and intake mixture temperature are increased at the same conditions of engine speed and load. and that $\textrm{NO}_{x}$ emissions are decreased. while soot emissions are increased owing to the decrease in intake and exhaust oxygen concentrations and the increase in equivalence ratio. Thus ond can conclude that $\textrm{NO}_{x}$ and soot emissions are considerably influenced by the cooled EGR.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.390-395
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• 2003

The effect of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rate are experimentally investigated by using an once-through boiler with FGR system. The purpose of this study is to develop the FGR control system for reducing NOx in a boiler. Intake and exhaust oxygen concentrations, and equivalence ratio are applied to discuss the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that NOx emissions are decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.100-111
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• 2002

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle, four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(EGR) control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $NO_x$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to survey the effect of intake mixture temperature on performance and exhaust emissions, the intake mixtures of fresh air and recirculated exhaust gas are heated by a heating device with five heating coils made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that $NO_x$ emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature. Thus one can conclude that the performance and exhaust emissions are considerably influenced by the cooled EGR.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.500-507
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• 1989

The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve timing influence greatly to the volumetric efficiency, it is very convenient and time saving if we can optimize these parameters by computation before we enter into long time fact finding engine tests. In this study we have developed a semi-empirical engine simulation program for the determinations of intake and exhaust valve timings, valve lifts, intake and exhaust port diameters in order to obtain highest volumetric efficiency. In this computation it requires only the measured variational pressures in intake and exhaust port. Using these variational pressures as an input data for our simulation program, we can calculate volumetric efficiency more accurately and can save computing time drastically. To confirm the validity of our simulation program we have made engine operation test in parallel and taken the experimental data. Comparing the computation result with the experimental data obtained through real engine test it has shown only the difference of 3%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5912-5918
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• 2014

Owing to highly developed industries and the use of fossil fuels, environmental problems becoming becoming pressing issues globally. Therefore, a study of automobile exhaust is urgently needed. Generally, air is sucked into the engine through the intake manifold. The aims of this study were to reduce the exhaust from used cars and increase the output by removing carbon deposits, which are considered a reason for the increasing exhaust and reduction of output, and the reduction of exhaust, variation of output and stability of idle speed were analyzed. The formation of carbon deposits within the suction manifold was investigated through a test device (KD147). In the intake manifold, the exhaust cleaning effect was confirmed.

• 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.