• Journal of Power System Engineering
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• v.8 no.1
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• pp.18-23
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• 2004

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments-were performed at various engine loads while the EGR rates were set from 0% to 20%. The emissions trade-off and combustion of diesel engine are investigated. Hot and cooled EGR are achieved without cooling and with cooling respectively. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar at load 20%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5082-5088
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• 2015

In this paper, durability test of 1000cc level gasoline engine has been carried out. Durability test set total 300 hours and WOT condition. Engine torque, power, fuel consumption, blow-by gas flow rate, and oil pressure are measured to analyse performance variation by time. As a result, engine performance of high rpm range gradually reduced by time but for relatively low rpm range shows stable performance. Blow-by gas flow rate shows 0.4% of averaged induction air flow rate, which is excellent rate for 1000cc level gasoline engine. Engine torque and fuel consumption data show the break-in upto 100 hours and aging trend after that. After 300 hours, engine is disassembled and each part is checked for the damage or crack.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.392-400
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• 2016

In this paper, a study based on engine operating conditions versus hybrid excavator engines was conducted about the engine performance and fuel consumption via the 1-D engine simulation model. First of all, engine operating points with performance and emission were determined by driving patterns. The 1-D HFEM(High Frequency Engine Model) was developed for deep insight into engine combustion and the energy conversion phenomena. In accordance with changing operating points, especially High Idle and Rated output conditions, engine parameters and systems such as turbocharger(Waste Gate Turbocharger and Variable Geometry Turbocharger) injection strategies and EGR(Exhaust Gas Recirculation) should be considered. Therefore, various configurations and parametric analysis with optimization methods in hybrid excavator were simulated and optimized by NLPQL(Non-linear Programming by Quadratic Lagrangian algorithm) in 1-D HFEM. As a result, the fuel consumption with the developed hybrid electric excavator engine could be significantly decreased and bsfc(Brake Specific Fuel Consumption) was also reduced about 5 % to 7 % without any performance degradation.

• Journal of the Korean Institute of Gas
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• v.12 no.3
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• pp.7-12
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• 2008

In this study, a spark ignition engine operated with the DME blended LPG fuel was investigated experimentally. Performance, emissions characteristics including hydrocarbon, CO, NOx, and combustion stability of an SI engine fuelled with DME blended LPG fuel were examined at $1200{\sim}5200\;rpm$. Results showed that stable engine operation was possible for a wide range of engine loads within 20% mass content of DME fuel. Also, engine output power within 10% mass content of DME fuel was comparable to that of pure LPG fuel operation. However, engine output power was decreased and break specific fuel consumption (BSFC) was severely increased with the amount of blended fuel as the energy content of DME was much lower than that of LPG. DME blended LPG fuel is expected to be potential for enlarging DME market.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.92-97
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• 2017

Kerosene (Coal oil) is a particularly attractive fuel because it is widely used to power jet engines of aircraft as jet fuel and some rocket engine. This paper describes the performance and emission characteristics according to the collant temperature of combustion chamber head of spark ignition engine fuelled with kerosene. As a result, the following knowledge is obtained. As the collant temperature of combustion chamber head is decreased, torque, volumetric efficiency and brake specific fuel consumption have been increased. When coolant temperature of combustion chamber lower, THC emission increased but CO and $NO_x$ emission decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.42-49
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• 2011

To expand lean misfire limit and improve combustion stability, the effects of port masking were estimated to secure basic data for applying the mechanism to SI engine instead of asymmetrical port and port throttling devises. For this purpose, various shapes and ratios of masking plates were mounted between port and manifold. The masking effects were evaluated by mixture response test under various load and speed conditions. The results showed that lean misfire limits were expended and fast combustion was observed for all masking shapes and ratios, especially, the effect of diagonal 1/4 masking was remarkable. In conclusion, the port masking method could be easily applied to engine without redesign of port for improving part load performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.188-194
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• 2005

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments were performed at various engine loads while the EGR rates were set from $0\%$ to $30\%.$ The emissions trade-off and combustion of diesel engine are investigated. The brake specific fuel consumption rate is very slightly fluctuated with EGR in the range of experimental conditions. The ignition delay increased with increasing EGR rate. The maximum value of premixed combustion for the rate of heat release is increased with increasing EGR rate. NOx emissions are decreased with increasing EGR rate at high load and high speed. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.81-89
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• 2014

This study researched on the effect of HP/LP-EGR system to improve fuel consumption of Low Temperature Combustion Engine. Firstly, low temperature combustion engine with HP/LP-EGR system was established using 6.0L wastegate turbocharger HDDI engine. And suppliable EGR rate of the engine was proven to be enough to realize stable low temperature combustion. Then, optimum operating strategy was founded to develop fuel consumption of the engine. Control parameters were HP/LP-EGR valve and IPCV(Intake Pressure Control Valve) duty. Experiments method was that characteristics of the engine were measured and analyzed according to HP/LP-EGR strategies while EGR rate was fixed. Operating range for the strategy were divided into three parts, low load for low temperature combustion, high load for conventional diesel combustion, and transient condition. Finally, with the above strategy of this study, BSFC of the engine was improved about 2% compared to the base engine, and emission level, NOx and PM, met Tier4Final emission regulation.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.42-49
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• 2014

The gasoline direct injection (GDI) system is considerably spreading in automotive market due to its advantages. Nevertheless, since GDI system emit higher particle matter (PM) due to its combustion characteristics, it is difficult to meet strengthened emission regulation in near future. For this reason, a combined GDI with MPI system, so-called, dual injection (DUI) system is being investigated as a supplemental measure for the GDI system. This paper focused on power and fuel consumption effect by injection mode strategy of DUI system in part load and idle engine operating condition. In this study, port fuel injectors are installed on 2.4 liters GDI production engine in order to realize DUI system. And, at each injection mode, DOE (design of experiment) method is used to optimize engine control parameters such as dual injection ratio, start of injection timing, end of injection timing, CAM position and so on. As a consequence, DUI mode shows slightly better or equivalent fuel efficiency compared to conventional GDI engine on 9 points fuel economy mode as well as MPI mode shows less fuel consumption than GDI mode during idle operation. Furthermore, DUI system shows improvement potential of maximum 2.0% fuel consumption and 1.1% performance compared to GDI system in WOT operating condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.43-48
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• 2008

The exhaust emissions of diesel engine are recognized as a major cause influencing environment strongly. In this study, the possibility of biodiesel fuel and oxygenated fuel(dimethoxy methane; DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel(biodiesel fuel 90vol-%+DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load, in comparison with the diesel fuel. But, power, torque and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counterplan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF(95 vol-%) and DMM(5 vol-%) blended fuel and cooled EGR method(15%).