• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.90-96
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• 2019

Natural gas has been regarded as one of major alternative fuels, because of the increment of mining shale gas and supplying PNG(Pipeline Natural Gas) from Russia. Thus, it needs to broaden the usage of natural gas as the increasing its supplement. In this situation, application of natural gas on the transport area is a good suggestion to reduce exhaust emissions such as CO₂(carbon dioxides) and soot from vehicles. For this reason, natural gas can be applied to SI(spark ignition) engines due to its anti-knocking and low auto-ignitibility characteristics. Recently, since turbocharged SI engine has been widely used, it needs to apply natural gas on the turbocharged SI engine. However, there is a major challenge for using natural gas on turbocharged SI engine, because it is hard to make natural gas direct injection in the cylinder, while gasoline is possible. As a result, there is a loss of fresh air when natural gas is injected by MPI (multi-point injection) method under the same intake pressure with gasoline-fueled condition. It brings the power reduction. Therefore, in this research, intake pressure was increased by controling the turbocharger system under natural gas-fueled condition to improve power output. The goal of improved power is the same level with that of gasoline-fueled condition under the maximum torque condition of each engine speed. As a result, the maximum power levels, which are the same with those of gasoline-fueled conditions, with improved brake thermal efficiency could be achieved for each engine speed (from 2,000 to 6,000 rpm) by increasing intake pressure 5-27 % compared to those of gasoline-fueled conditions.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.5
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• pp.69-82
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• 1988

Heat transfer experiment is carried out during the performance test of the 4-cylinder 4-stroke cycle turbo-charged gasoline engine. Cycle simulation employing the measured pressure in cylinder, the cooling water temperature and flow rate and others is carried out in order to calculate the gas temperature in cylinder. In this simulation combustion process was simulated by Annand's two zone model and suction, compression, and other processes are calculated completely. From this simulation, we can obtain not only the heat transfer coefficient but also the flame speed, turbulent burning velocity, flame factor and the boiling condition of cooling passage. The results are investigated with engine speed, equivalence ratio and spark advance.

• The KSFM Journal of Fluid Machinery
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• v.19 no.6
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• pp.43-49
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• 2016

A performance analysis of a gasoline engine with a 2-stage turbocharger system for unmanned aerial vehicle(UAV) was conducted. One dimensional system analysis was conducted for the requirements of turbochargers and adequate turbochargers were selected from commercially available models for automobiles. Modeling and simulation were performed by Ricardo WAVE. Gasoline engine modeling was based on a 2.4 L 4-cylinder engine specification. The selected turbochargers and intercoolers were added to the engine model and simulated at 40,000 ft altitude condition. The results of the engine model and 2-stage turbocharger system model simulation showed break power 93 kW which is appropriate power required for the engine operation at the ambient conditions of 40,000 ft altitude.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.128-139
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• 2000

Environmental concerns and shortage of petroleum have promoted considerable interest in the use of alternate fuels in stationary diesel engine. In this study, a heavy-duty, intercooler-turbocharged 6-cylinder stationary diesel engine was converted into stationary gas engine fueled with propane or natural gas for the cogeneration plants. One of the most important factors in the combustion features of a stationary gas engine is the fuel composition and operating parameters in terms of compression ratio, spark advance, and engine loads. Experiments with different fuel gas and load conditions were carried out with combustion pressure analysis and NOx measurement. Combustion analysis based on P-$\theta$ diagrams was also investigated by means of combustion duration and cycle variation. Compression ratio is 10.0 and ignition timing is set by using the gasoline setting as a base line and advanced toward BTDC. The results show that fuel composition and spark advance have dominant effects on combustion and NOx characteristics at operating conditions.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.4
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• pp.13-23
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• 1986

The power of an international combustion engine depends on its ability to inhale air whether it is naturally aspirated or turbocharged. The use of fuel injection allows engine efficiency to be increased through a more even distribution of the air/fuel ratio throughout the engine's operation range. The theoretical value for complete combustion in an engine is commonly refered to as stoichiometric, which means that we require 14.7 parts of air to 1 part of gasoline. This stoichiometric ratio can be more closely maintained with electronically controlled fuel injection than it can with carburetion. Because of the greater efficiency of the engine using fuel injection, a horse power increase of at least 10% is produced over its carburetor version. In addition, better fuel economy and less exhaust emissions are also obtained.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.5
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• pp.46-59
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• 1990

The development of the effective computer simulation program which predicts the performances and emissions of the multi-cylinder turbocharged gasoline engine has been described in the first paper. In this paper, the comparison between the predictions and experiments of the transient pressure at each point in the intake and exhaust systems was made to examine the validity and availability of the simulation models adopted. This test was performed for the engines equipped with different turbochargers under various operating conditions. The results of calculation showed good agreements with the experimental data and proved that the simulation program developed can be used for the matching of the turbocharger to the engine.

• Steel and Composite Structures
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• v.43 no.5
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• pp.523-532
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• 2022

Turbocharger technology is one of the ways to survive in a competitive market that is facing increasing demand for fuel and improving the efficiency of vehicle engines. Turbocharging allows the engine to operate at close to its maximum power, thereby reducing the relative friction losses. One way to optimally understand the behavior of a turbocharger is to better understand the heat flow. In this paper, a 1.7 liter, 4 cylinder and 16 air valve gasoline engine turbocharger with compressible, viscous and 3D flow was investigated. The purpose of this paper is numerical investigation of the number of heat transfer in gasoline engines turbochargers under 3D flow and to examine the effect of different types of coatings on its performance; To do this, modeling of snail chamber and turbine blades in CATIA and simulation in ANSYS-FLUENT software have been used to compare the results of turbine with experimental results in both adiabatic and non-adiabatic (heat transfer) conditions. It should be noted that the turbine blades are modeled using multiple rotational coordinate methods. In the experimental section, we simulated our model without coating in two states of adiabatic and non-adiabatic. Then we matched our results with the experimental results to prove the validation of the model. Comparison of numerical and experimental results showed a difference of 8-10%, which indicates the accuracy and precision of numerical results. Also, in our studies, we concluded that the highest effective power of the turbocharged engine is achieved in the adiabatic state. We also used three types of SiO₂, Sic and Si₃N₄ ceramic coatings to investigate the effect of insulating coatings on turbine shells to prevent heat transfer. The results showed that SiO₂ has better results than the other two coatings due to its lower heat transfer coefficient.

• Journal of ILASS-Korea
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• v.25 no.4
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• pp.162-169
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• 2020

The worldwide focus on reducing the emissions, fuel and lubricant consumption in T-GDI engines is leading engineers to consider the crankcase ventilation and oil mist separation system as an important means of control. In today's passenger cars, the oil mist separation systems mainly use the inertia effect (e.g. labyrinth, cyclone etc.). Therefore, this study has investigated high efficiency cylinder head-integrated oil-mist separator by using a compact multi-impactor type oil mist separator system to ensure adequate oil mist separation performance. For this purpose, engine dynamometer testing with oil particle efficiency measurement equipment and 3D two-phase flow simulation have been performed for various engine operating conditions. Tests with an actual engine on a dynamometer showed oil aerosol particle size distributions varied depending on operating conditions. For instance, high rpm and load increases bot only blow-by gases but the amount of small size oil droplets. Submicron-sized particles (less than 0.5 ㎛) were also observed. It is also found that the impactor type separator is able to separate nearly no droplets of diameter lower than 3 ㎛. CFD results showed that the complex aerodynamics processes that lead to strong impingement and break-up can strip out large droplets and generate more small size droplets.