• Journal of Power System Engineering
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• v.10 no.2
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• pp.5-10
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• 2006

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engine are recognized main cause which influenced environment strong. In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated common rail diesel engine. The smoke emission of biodiesel fuel 30vol-%(max. content) was reduced in comparison with diesel fuel, that is, it was reduced approximately 60% at 4000rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3383-3388
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• 2014

An experimental study was performed to compare the characteristics of the combustion pressure and exhaust emissions in the case of using pure diesel when the EGR rate was changed in a CRDI 4-cylinder diesel engine with those using biodiesel blended and pure diesel fuel. In this study, the EGR rate variation were conducted at an engine speed of 2000rpm with fuel with a biodiesel blended rate of 20%. The combustion pressure of the biodiesel blended rate 20% and pure diesel fuels decreased with increasing EGR rate. The IMEP of biodiesel was higher than that of ULSD (Ultra low sulfur diesel). The emission results showed that the NOx emission of biodiesel blended fuel with increasing EGR rate was higher than that of ULSD. In addition, the NOx emission of biodiesel blended and diesel fuel decreased with increasing EGR rate. The CO and soot, $CO_2$ emissions increased with increasing EGR rate, and the CO and soot emissions from the biodiesel blended fuel were lower than that of ULSD but the $CO_2$ emissions were higher.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.61-66
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• 2007

A CRDI diesel engine used to commercial vehicle was fueled with 20% biodiesel fuel(BDF 20) in excess of 150 hours. Engine dynamometer testing was completed at regularly scheduled intervals to monitor the engine performance and exhaust emissions. The engine performance and exhaust emissions were sampled at 1 hour interval for analysis, Also, BSEC with BDF 20 resulted in lower than with diesel fuel. Since the biodiesel fuel used in this study includes oxygen of about 11%, it could influence the combustion process strongly. So, BDF 20 resulted in lower emissions of carbon monoxide, carbon dioxide, and smoke emissions without special increase of oxides of nitrogen than diesel fuel. It was concluded that there was no unusual deterioration of the engine, or any unusual change in exhaust emissions from using the BDF 20.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.145-151
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• 2010

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several grooves with inclined plane on the piston crown to generate swirl during the compression and expansion strokes in the cylinder in order to improve the atomization of fuel. The other is a toroidal piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2573-2578
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• 2014

An experimental study was performed to investigate the characteristics of combustion pressure and exhaust emissions when the pilot injection timing and EGR rate were changed in a CRDI 4-cylinder diesel engine using bio-diesel blended fuel. The pilot injection timing and EGR rate have a significant impact on the combustion and emission characteristics of diesel engine. In this study, the pilot injection timing and EGR rate variation were conducted to 2000rpm of engine speed with fuel of bio-diesel blended rate 20%. In these experimental results, IMEP was shown maximum pressure at pilot injection timing BTDC$10^{\circ}$ combustion pressure and heat release rate were decreased in proportion to increase of EGR rate under the same pilot injection timing conditions. The NOx emission was decreased with increasing the EGR rate without influence on pilot injection timing. However, soot emission was reduced to a minimum at pilot injection timing BTDC$20^{\circ}$.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.32-37
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• 2011

Biodiesel fuel is already remarkable alternative fuel in many countries. So, many studies are performed on the environmental or economic effects as well as the characteristics of diesel engine fueled biodiesel in combustion and emission. In this study, an CRDI diesel engine used to commercial vehicle was fueled with diesel fuel and 20% biodiesel blended fuel (BDF 20%) with city mode in excess of 300 hours. Engine dynamometer testing was completed at regularly scheduled intervals to monitor the engine performance and exhaust emissions. The engine performance and exhaust emissions were sampled at 1 hour interval for analysis. To check the engine parts (valve and injector), the engine was inspected after test. It was concluded that there were no unusual deteriorations of the engine, or any unusual changes in engine power and exhaust emissions in spite of operation of 300 hours with BDF 20%.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.171-179
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• 2009

An object of this study is to confirm application characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air mass flow rate and the charging air cooling ratio of the intercooler were measured in an experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. The vortex tube designed with fundamental data was applied to a conventional common-rail diesel engine instead of the intercooler. Its application characteristics, engine performances and emissions were investigated. From this experimental results, we suggested the vortex tube can be applied to a conventional common-rail diesel engine throughout extra complement. We can also expect the higher cooling effect, if we consider the application of the vortex tube in supercharging diesel engine without the intercooler.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.172-178
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• 2008

An object of this study is to confirm performance characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air flow rate and the ${\Delta}T_c$ decrease ratio of the intercooler were measured in a experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. To investigate energy separation characteristics of the vortex tube, the measured turbo pressure was applied to the vortex tube inlet and the ${\Delta}T_c$ decrease ratio was compared with one of the intercooler in the cold air mass flow ratio similar to the intake air flow rate of the experimental engine. From the results, we found that the energy separation ratio is increased according to of the inlet pressure and the ${\Delta}T_c$ decrease ratio of the vortex tube apparatus is higher than one of the intercooler at low engine speed and engine load of medium and low.

• Journal of ILASS-Korea
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• v.11 no.2
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• pp.69-74
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• 2006

This is an experimental study on the performance characteristics and combustion characteristics of common-rail type diesel engine by using ultrasonic energy. It is carried out engine performance by engine dynamometer test and combustion characteristics using ultrasonically irradiated diesel fuel in comparison with using conventional diesel fuel. In analyzing the experiments of these results generally, these are obtained as follows. There is an affirmative effect on the side of the improvement of power and the reduction of smoke by applying the ultrasonically irradiated diesel fuel to the common rail engine. But there is less effect on the side of improvement of BSFC.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.53-59
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• 2011

The using of diesel engine will be increased in the world for fuel economy. But diesel engine emits harmful emissions such as much NOx, smoke etc. In this study, experiments were performed to investigate the spray characteristics of diesel spray in a common-rail system according to fuel temperature, injection pressure, injection period and fuel viscosity etc. using a high speed video camera. Diesel oil has different spray patten due to injection pressure and injection period in a common-rail system. A Filter pressure was influenced by fuel temperature which was turned to fuel viscosity related to a fluid flowing. The effect of the bio-diesel fuel mixing ratio on the spray and atomization characteristics was also investigated at various experimental conditions. It shows that the droplet atomization characteristics of bio-diesel fuel showed deteriorated results as the mixing ratio of biodiesel increased because of the high viscosity.