• 한국자동차공학회논문집
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• 제22권6호
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• pp.83-88
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• 2014

LTC(Low Temperature Combustion) technology has been studied to see feasibility of the combustion technology applied to heavy-duty engines on the laboratory scale. This study succeeded to develop a demo engine including realized low temperature combustion under partial load conditions. To find the best feasible LTC strategy, various LTC combustion methods such as PPCI, MK and highly diluted mixing controlled LTC were conducted on 6.0L heavy duty diesel engine. Air management system was re-designed to make these combustion scheme stable and the re-designed air system helped expand LTC operating range. This study finally revealed plausible LTC concept to maximize benefit of the alternative combustion technology while overcoming handicaps of the LTC strategy.

• 한국산학기술학회논문지
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• 제7권5호
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• pp.784-787
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• 2006

배기가스 재순환장치는 디젤엔진에서 질소산화물을 저감시키는 기술로서 알려져 있다. 그러나 시스템 적용시 연료소비와 입자상물질을 증가시키기 때문에 기술 적용하는데 있어서 상당히 어려움이 있다. 그래서 실린더내의 연소시스템을 고려한 최적의 배기가스순환 비율을 산정하는 것은 매우 중요하다. 따라서 본 논문은 여러 가지의 EGR율을 변화시키면서 연소와 배기가스에 미치는 영향을 조사했다.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.178-184
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• 2015

According to the regulation on the environment and fuel efficiency is becoming strict, many experiments are conducted to improve efficiency and emission in internal combustion engines. LTC (Low temperature combustion) technology is a promised solution for low emissions but there are a few barriers for the commercial engine. This paper includes optimization that applies LTC method to heavy duty diesel engine. Adequate LTC was applied to low and middle load as adaptability in heavy duty diesel engine, and optimization focused on reduction of fuel consumption was proceeded at high load. Through this research, strategy for practical use of LTC was selected, and fuel consumption has improved on the condition that satisfies the emission regulation at systematic viewpoint.

• 대한조선학회 특별논문집
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• 대한조선학회 2017년도 특별논문집
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• pp.54-58
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• 2017

The vessels which are operated in ECA (Emission Control Area) after $1^{st}$ January 2016 shall be complied with revised NOx emission requirement (Tier III). Effective solutions for NOx emission requirement are SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) and Installation of LNG Dual Fuel Engine. This study is considered the design modification as per application of LNG Ready notation. In case of LNG Ready - S notation, the vessel shall be retrofitted the Main engine with Dual fuel engine and LNG Fuel system after delivery. On this paper, the entire process for design modification was explained to meet the requirement for LNG Ready notation.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1247-1254
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• 2000

The effects of recirculated exhaust gas on the characteristics of $NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The simultaneous control of $NO_x$ and soot emissions in diesel engines is targeted in this study. The EGR system is used to reduce $NO_x$ emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector has 144 nozzles in 1.0 mm diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration and the mean equivalence ratio calculated by the intake air flow and fuel consumption rate, and the exhaust oxygen concentration measured are used to analyse and discuss the influences of EGR rate on $NO_x$ and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions are decreased and soot emissions are increased owing to the drop of intake oxygen concentration and exhaust oxygen concentration, and the rise of equivalence ratio as the EGR rate rises.

• 대한기계학회논문집B
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• 제37권2호
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• pp.139-148
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• 2013

본 연구에서는 1kW 급 SOFC 시스템의 AOGR(anode off-gas recirculation)을 위한 이젝터를 설계하고 이젝터 적용시의 시스템 효율을 매개변수 연구를 통해 알아보았다. 화공해석 프로그램를 이용하여 이젝터의 작동 조건을 계산하였고, 전역 최적값을 보장하면서도 CFD 계산에 따른 부하를 최소화하기 위하여 유전 알고리듬과 크리깅 모델을 이용하여 최적화를 진행하였다. 최적화를 통해 음속 이젝터에서 가장 큰 영향을 미치는 설계 변수가 이젝터의 목직경과 1 차 노즐의 위치임을 식별하였다. 유동변수에 대한 매개변수 연구를 통해 설계된 이젝터는 1kW 급 SOFC 의 다양한 작동 조건에서 충분한 유연성을 가지며, SOFC 에 적용시 증기의 56% 와 연료의 8.4% 절감이 가능함을 보였다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.136-144
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• 2010

Exhaust gas recirculation (EGR) is an emission control technology allowing significant NOx emission reduction from light-and heavy duty diesel engines. The future EGR type, dual loop EGR, combining features of high pressure loop EGR and low pressure loop EGR, was developed and optimized by using a commercial engine simulation program, GT-POWER. Some variables were selected to control dual loop EGR system such as VGT (Variable Geometry Turbocharger)performance, especially turbo speed, flap valve opening diameter at the exhaust tail pipe, and EGR valve opening diameter. Applying the dual loop EGR system in the light-duty diesel engine might cause some problems, such as decrease of engine performance and increase of brake specific fuel consumption (BSFC). So proper EGR rate (or mass flow) control would be needed because there are trade-offs of two types of the EGR (HPL and LPL) features. In this study, a diesel engine under dual loop EGR system was optimized by using design of experiment (DoE). Some dominant variables were determined which had effects on torque, BSFC, NOx, and EGR rate. As a result, optimization was performed to compensate the torque and BSFC by controlling start of injection (SOI), injection mass and EGR valves, etc.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.827-835
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• 1998

The effects of recirculated exhaust gas on the wear of cylinder liner piston and piston rings have been investigated by the experiment with a two-cylinder four cycle indirect injection diesel engine operating at 75% load and 1600 rpm speed For the purpose of comparison between the rates of two cylinders with and without EGR the recirculated exhaust gas is sucked into one of two cylinders after the soot among exhaust emissions is removed by an intntionally designed cylinder-type scrubber equipped with 6 water injectors(A water injector has 144 nozzles of 1.0 mm diame-ter) while only the fresh air into another cylinder. These experiments are carried out on the fuel injection at a fixed $15.3^{\circ}$ BTDC timing. It is found that firstly the mean wear amount of cylinder liner with EGR is more increased in the measurement positions of the second half than of the first half and the mean wear amount without EGR is almost uniform regardless of measurement posi-tions secondly the wear rates of the first and second piston ring(compression ring)thickness with EGR are more than twice but the wear rate of oil ring thickness without EGR is more increased than that with EGR and finally the wear rate of piston skirt with EGR is a little bit increased but the piston hed diameter is rather increased owing to soot adhesion and corrosion wear and espe-cially larger with EGR.

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.896-902
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• 2009

EGR is applied in order to lower temperature of combustion chamber by using the specific heat of carbon dioxide in engine exhaust gas. However, the problem of EGR system in diesel engine is high PM concentration. Combined EGR system can be reduced it by mixing exhaust gas of gas engine into the intake air of diesel engine. This experimental study was designed for EGR system for both engines use. The results of EGR experimental study by using diesel engine and gas engine are as follows. 1) The pressure of combustion and rate of heat release decreased. 2) The specific fuel consumption increased. But, up to middle load, it little increased. 3) NO concentration has decreased up to 50% in almost all combustion area. 4) The variation of the PM concentration at low load is not so seen. But at high load, PM increased rapidly when concentration of oxygen is decreased and most of it caused the increasing of Dry Soot.

• Journal of Advanced Marine Engineering and Technology
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• 제24권3호
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• pp.70-78
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• 2000

The effects of recirculated exhaust gas on the characteristics of ;$NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The purpose of the present study is to develop the EGR control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal apparatus with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector is made up 144 nozzles with 1.0mm in diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration obtained by the intake air flow and the oxygen concentration in the recirculated exhaust gas, and the exhaust oxygen concentration measured in exhaust manifold are used to analyse and discuss the influences of EGR on NOx and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions decrease and soot emissions increase owing to the drop of intake oxygen concentration and exhaust oxygen concentration as EGR rate rises. Also, one can conclude that it is sufficient for the scrubber EGR system with a novel diesel soot removal apparatus to reduce $NO_x$ emissions, but not to reduce soot emissions.