• Journal of Advanced Technology Convergence
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• v.2 no.3
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• pp.17-24
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• 2023

I am designing a research paper with the aim of studying hybrid vehicles. Hybrid vehicles, as the next-generation automobiles, feature a combination of internal combustion engines and battery engines, resulting in a revolutionary reduction in fuel consumption and harmful gas emissions compared to conventional vehicles. The electric motor in hybrid cars derives power from a high-voltage battery installed within the vehicle, which is recharged during vehicle motion. In contrast to traditional cars, which often experience energy losses due to idling caused by traffic congestion, hybrid systems optimize efficiency by skillfully managing the interplay between the internal combustion engine and the electric motor. This approach effectively addresses the inherent drawbacks of gasoline or diesel engines.Hybrid cars offer an array of benefits, including improved fuel efficiency, environmental friendliness, cost-effectiveness, and reduced noise emission. Consequently, they are progressively becoming a favored alternative among a growing number of individuals. This research endeavor has the potential to contribute towards curbing environmental pollution and dedicating efforts to future automotive research.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.191-193
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• 2012

The use of diesel engines has recently increased due to the need for internal combustion engines with a high thermal efficiency and low harmful exhaust gas. The PCCI(premixed charged compression ignition) technology has been studied specifically to simultaneously reduce NOx and PM. While the PCCI means has the merit of reducing NOx and PM, control of the combustion phase is difficult. In this study, Flame visualization was then performed with an endoscope system in order to compare combustion flame characteristics in an commercial diesel engine.

• Environmental Engineering Research
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• v.14 no.2
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• pp.95-101
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• 2009

Natural gas is a promising alternative fuel of internal combustion engines. In this paper, the combustion and emission characteristics were investigated on a natural gas engine at two different fuel injection timings during the intake stroke. The results show that fuel injection timing affects combustion processes. The optimum spark timing (MBT) achieving the maximum indicated mean effective pressure (IMEP) is related to fuel injection timing and air fuel ratio. At MBT spark timing, late fuel injection timing delays ignition timing and prolongs combustion duration in most cases. But fuel injection timing has little effect on IMEP at fixed lambdas. The coefficient of variation (COV) of IMEP is dependent on air fuel ratio, throttle positions and fuel injection timings at MBT spark timing. The COV of IMEP increases with lambda in most cases. Late fuel injection timings can reduce the COV of IMEP at part loads. Moreover, engine-out CO and total hydrocarbon (THC) emissions can be reduced at late fuel injection timing.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.285-294
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• 2003

This study was carried out to propose a new-concept internal combustion engine which has great potential advantages to the conventional engines. Proposed new-concept engine is a kind of rotary engine. A rotor is rotating concentrically in a cylinder which is divided into two partitioning valves, and it makes four compartments in the cylinder. The volumes of each of four compartments are changing continuously with the rotor movement and performs the functions of intake, compression. expansion and exhaust simultaneously. Expected thermal efficiency for the real cycle is 26 percent at conditions of 1,000 rpm and compression ratio of 8.0, which is 3 to 4 percent higher than that of the conventional engines such as the piston engine, gas turbine and Wankel rotary engine. A simulation procedure proved that the new concept engine is functional, and has many potential advantages compared to the existing conventional engines.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.373-381
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• 2012

To determine the performance characteristics of motorcycle engine using biogas for practical use, the intake system of a 110 cc motorcycle engine is properly modified to operate with biogas as a fuel. Biogas is a potentially renewable fuel for replacing gasoline in future, but it has high percentage of $CO_2$ that could lead to slow the burning rate of biogas-air mixture and cause instability in combustion. Thus, the performance characteristics of biogas-fueled motorcycle engines could be different from those of gasoline motorcycle engines. In this paper, the important parameters of performance characteristics (such as: power output, thermal efficiency, fuel consumption, exhaust emission,${\cdots}$) of biogas-fueled motorcycle engine are studied and estimated with change of engine speed and load. The obtained results when operating with biogas are used to compare with that of gasoline fuel under the same operating conditions. Engine speed in the experimental is changed from 1500 rpm (idle-mode) up to 3500 rpm by a step of 500 rpm. Engine load is changed from zero to maximum load with the help of an exciting voltage device from generator-type dynamometer. The experimental results show that the tested engine operated with richer biogas-air mixture than that of gasoline-air mixture under the same test conditions. Biogas-fueled engine gives a higher fuel consumption and lower thermal efficiency under the same power output. Brake thermal efficiency of biogas engine is found to be about 3% lower than gasoline-fueled motorcycle engine for whole range of speed. Exhaust emission of biogas-fueled motorcycle engine (such as: CO, HC) is found to be lower than the limitation level of the emission standards of Vietnam for motorcycle engines (CO <4.5% HC <1200 ppm).

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.41-47
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• 2005

Exhaust gas emissions from internal combustion engines are one of the major sources of air pollution. And. it is extremely difficult to increase gasoline engine efficiency and to reduce NOx and PM(particulate matter) simultaneously in diesel combustion. This paper offers some basic concepts to overcome the above problems. To solve the problems, a recommended technique is CAI(controlled auto-ignition) combustion. In this paper. internal EGR(exhaust gas recirculation) effect is suggested to realize CAI combustion. An experimental study was carried out to achieve CAI combustion using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). A flame trap was used to simulate internal EGR effect and to increase flame propagation speed in the CVCC. Flame propagation photos and pressure signals were acquired to verify internal EGR effect. Flame trap creates high speed burned gas jet. It achieves higher flame propagation speed due to the effect of geometry and burned gas jet.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.113-119
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• 2014

Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.9
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• pp.727-734
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• 2015

Recently, because of the increased oil prices globally, there have been studies investigating the improvement of fuel-conversion efficiency in internal combustion engines. The improvements realized in thermal efficiency using lean combustion are essential because they enable us to realize higher thermal efficiency in gasoline engines because lean combustion leads to an increase in the heat-capacity ratio and a reduction of the combustion temperature. Gasoline direct injection (GDI) engines enable lean combustion by injecting fuel directly into the cylinder and controlling the combustion parameters precisely. However, the extension of the flammability limit and the stabilization of lean combustion are required for the commercialization of GDI engines. The reduction characteristics of three-way catalysts (TWC) for lean combustion engines are somewhat limited owing to the high excess air ratio and low exhaust gas temperature. Therefore, in the present study, we assess the reaction of exhaust gases and their production in terms of the development of efficient TWCs for lean-burn GDI engines at 2000 rpm / BMEP 2 bar operating conditions, which are frequently used when evaluating the fuel consumption in passenger vehicles. At the lean-combustion operating point, $NO_2$ was produced during combustion and the ratio of $NO_2$ increased, while that of $N_2O$ decreased as the excess air ratio increased.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.289-294
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• 2006

Better fundamental understanding of the interactions between the in-cylinder flows and combustion process is an important requirement for further improvement in the fuel economy and emissions of internal combustion(IC) engines. Flow near a spark plug at the time of ignition plays an important role for early flame kernel development(EFKD). Velocity data measurements in this study were made with a two-component laser Doppler velocimetry(LDV) near a spark plug in a single cylinder optical spark ignition(SI) engine with a heart-shaped combustion chamber. LDV velocity data were collected on an individual cycle basis under wide-open motored conditions with an engine speed of 1,000rpm. This study examines and compares the flow fields as interpreted through ensemble, cyclic and discrete wavelet transformation(DWT) analysis. The energy distributions in the non-stationary engine flows are also investigated over crank angle phase and frequency through continuous wavelet transformation(CWT) for a position near a spark plug. Wavelet analysis is appropriate for analyzing the flow fields in engines because it gives information about the transient events in a time and frequency plane. The results of CWT analysis are provided and compared with the mean flows of DWT first decomposition level for all cycles at a position. Low frequency high energy found with CWT corresponds well with the peak locations of the mean velocity. The high frequency flows caused by the intake jet gradually decay as the piston approaches the bottom dead center(BDC).

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.27-34
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• 2003

Present combustion engines have reached almost at the limit of development due to the fundamental structural problems. This study was carried out to propose a new concept internal combustion engine which has great potential advantages to the conventional engines. Proposed new concept engine is a kind of rotary engine. A rotor is rotating concentrically in a cylinder which is divided into two partitioning valves. and it makes four compartments in the cylinder. The volumes of each of four compartments are changing continuously with the rotor movement, and performs the functions of intake, compression. expansion and exhaust simultaneously. The results of this study can be summarized as follows. 1. Expected theoretical thermal efficiency is 44.9 percent at the condition of 1000rpm and compression ratio of 8.0. which is almost the same as that of the conventional engines. i.e., piston and Wankel rotary engine. 2. The new concept engine has 2. working strokes in every revolution. Therefore. the new concept engine can reduce the specific weight and volume than four-stroke piston engine. 3. The torque variation is very small. therefore minimal noise and vibration are expectable. 4. The new concept engine can reduce mechanical energy loss than piston engine because neither crank mechanism nor eccentrical motion exists.