• 한국자동차공학회논문집
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• 제10권3호
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• pp.1-7
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• 2002

Recently, many researches for the improvement of DI diesel engines have been performed to reduce the fuel consumption and exhaust emissions. Among the various factors effect on combustion and emission in Dl diesel engines, one of the most important factors is the characteristics of the fuel spray. Accordingly, the investigation on the characteristics of spray is needed to analyze the diesel combustion exactly, In this study, the measurement technique fur injection rate using the Zeuch method was developed. In addition, the effects of nozzle hole number on the spray and flame were investigated by visualization experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2186-2191
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• 2003

This study is to investigate the effects of water induction through the air intake system on the characteristics of combustion and exhaust emissions in diesel engine. The effects of water induction through the air intake port were considered in IDI diesel engine in this study. The formation of NOx was significantly suppressed by decreasing the gas peak temperature during the initial combustion process because the water play a role as a heat sink during evaporating in the combustion chamber, but the smoke was slightly increased with increased water amount. Also, NOx significantly decreased with increase in water amount. A simultaneous reduction in smoke and NOx emissions can be obtained when water is injected into the combustion chamber by retarding the fuel injection timing more than without water injection.

• 한국분무공학회지
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• 제19권3호
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• pp.123-129
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• 2014

A diesel spray overall SMD (Sauter mean diameter) in a spray chamber was simulated with CFD by varying the compression ratio in the spray chamber from 18:1 to 100:1. The gas densities of the spray chambers for the compression ratios of 18:1 and 100:1 were 17.97 and $74.8kg/m^3$, respectively. Standard KIVA-3V code was used for the CFD simulation. Various fuel injection patterns such as single injection, pilot injection and split injection were used for the CFD simulation. Fuel injection pressures for the simulated diesel sprays are 90 and 120 MPa. As the compression ratio increases, the CFD simulated SMD was decreased, which was generally in agreement with previous experimental studies.

• 한국해양공학회지
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• 제13권3B호
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• pp.38-46
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• 1999

Increasing stringent emissions legislation and requirement of more effective energy used for diesel engine demand the fine control of the fuel injection system. Recently, the electromagnetic fuel injection control system for diesel engine is tried to realize the optimum diesel combustion by the feel back sensing as optical signal of combustion flame. The photo detectors were made for the feed back signal of electromagnetic fuel injection control for small DI diesel engine. Their abilities to detect defining combustion events were examined. By evaluating test results, it was shown that the wider acceptable optical range design of optical probe window face, and selection of installation position and installation method of detector were important point for improving sensing ability. The detector was shown to detect start and end of diffused combustion and maximum point of flame intensity impossible for pressure sensor, and also shown that the maximum point of flame intensity was 75% of accumulated heat release point within the experimental conditions.

• International Journal of Automotive Technology
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• 제8권1호
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• pp.27-31
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• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Therefore, the present study evaluates the effect of fuel injection characteristics on regeneration performance in a DOC and a catalyzed CR-DPF system. The temperature distribution on the rear surface of the DOC and the exhaust gas emission were analyzed in accordance with fuel injection strategies and engine operating conditions. A temperature increase more than BPT of DPF system was obtained with a small amount fuel injection although the exhaust gas temperature was low and flow rate was high. This increase of temperature at the DPF inlet cause PM to oxidize completely by oxygen. In the case of multi-step injection, the abrupt temperature changes of DOC inlet didn't occur and THC slip also could not be observed. However, in the case of pulse type injection, the abrupt injection of much fuel results in the decrease of DOC inlet temperatures and the instantaneous slip of THC was observed.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.9-14
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• 1997

The pump-pipe-injector system is that most commonly used type of injection equipment for diesel engines. In this study, a new electromagnetic fuel injection system was designed and carried out the experiment of single cylinder direct injection(DI) diesel engine. This system do not need the cam shaft for fuel injection. The effects of the injection timing on the combustion process and emission were investigated. The results are that 1) atomization was improved, 2) combustion pressure was increased and ignition delay became shorter than before, 3) Low smoke level guarantee with more advanced injection timing without abnormal combustion but NOX concentration was increased as the injection time advanced.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3085-3089
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• 2008

In order to reduce NOx and Soot emissions simultaneously, characteristics of diesel spray and combustion were investigated by numerical simulation with StarCD in this paper. This work focuses on effect of Spin Injection. A simulation model of combustion, spray and emissions is developed for heavy duty marine diesel engine application. Simulation is performed with change of spray angle between first and second directions at fixed engine speed, injection timing, injection duration and etc. The results show that Spin Spray Injection method can reduce NOx emission. And the results show that the 1st injection considerably interfere with 2nd injection characteristics.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.78-85
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• 2000

This study is to develop the diesel engine which has 6 cylinder natural aspiration direct injection type of 7.4$\ell$ with high performance, low emissions and low fuel consumption Finally the developed engine meets Korean `98 exhaust emission regulation for the city bus of heavy duty diesel engine by optimizing the various combustion parameters affecting performance and exhaust emissions. Combustion parameters are the swirl ratio of intake ports, the profile of injection pump`s cam affecting injection pressure, the design features of piston bowl of injection pump`s cam affecting injection pressure, the design features of piston bowl of combustion chamber and injector`s hole size. Through experimental analysis, various combustion parameters are optimized and the results are as follows; the swirl ratio is 2.20, the profile of injection pump`s cam is concave and re-entrant ratio, inner diameter of piston bowl and hole diameter of injector is 0.88,$\psi$64.0mm and $\psi$0.25mm respectively.

• 한국분무공학회지
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• 제4권4호
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• pp.17-23
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• 1999

Recently, many researchers have been studied a D.I. diesel engine because of the exhaust gas restriction and fuel consumption performance. It is well known that the fuel injection characteristics are the key factors on the diesel combustion and exhaust emission. In this study, the fuel injection characteristics of 5-hole injector and the combustion characteristics are investigated with the amount of fuel by means of the visualization method and visualization D.I. diesel engine system. As the results of the experiments, the spray pattern of the fuel injection and the diffusion flame of a D.I. diesel engine are clarified. In addition, combustion phenomena with operation conditions such as engine speed and engine load are made clear.

• 한국분무공학회지
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• 제27권2호
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• pp.101-108
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• 2022

Performance and emissions with different diesel injection methods were analyzed in a natural gas-diesel, dual-fuel engine under low-load conditions. Natural gas was supplied to intake port during the intake stoke to form a natural gas-air premixed mixture for all methods. Diesel was injected directly into the cylinder during the compression stroke in three ways: early injections, late injections, and a combination of early and late injections. The early injections had the highest thermal efficiency among the three methods owing to its highest combustion efficiency. The wide dispersion of diesel before the combustion initiation also allowed superior emissions characteristics.