• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.20-26
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• 2013

In this study, based on a 12L class diesel engine, a natural gas-diesel dual fuel engine was developed by adding natural gas fuel supply system. For optimal control of dual fuel engine, a conventional diesel engine ECU and a dual fuel ECU were utilized. To convert the dual fuel engine, MPI natural gas injectors were installed on the new modified intake manifold adapter. As a results, the dual fuel engine showed same level of torque, power performance and exhaust gas emissions as those of a diesel base engine.. Furthermore, overall fuel replacement rate was 70~76 % and total fuel cost saving was 37~40%.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.246-250
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• 2010

It was measured engine power, specific fuel consumption and exhaust emissions to analyze fuel economy between LNG dual fuel vehicle and base diesel one. The tested LNG dual fuel engine is converted from diesel engine having 12 liter heavy duty class. The power of LNG dual fuel engine is 5% lower than diesel one and the engine efficiency is also lower than diesel case. However the exhaust emission of diesel engine such as PM, NOx, CO and $CO_2$ showed higher than that of LNG duel fuel case except NMHC component. And economical analysis were carried out two cases for an aspect of fuel economy and environmental benefit. As a result, LNG dual fuel vehicle gives some economic benefit to whom both business party and public side respectively though considering the subsidy and price discount for diesel.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.29-36
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• 2015

This study is an 1-D numerical study prior to modification of diesel engine for power plants to natural gas/diesel dual fuel engine using GT-Power with 1.5MW diesel engine for power generation. Natural gas injector was installed to intake manifold for dual fuel engine model. Effects on engine performance and characteristics were investigated when dual fuel is used in unmodified diesel engine. The analysis was done under 5 conditions from 0% to 40% of mixing rate on 720RPM engine speed. As a result of research, the engine performance was decreased as increasing ratio of natural gas. Engine brake power was decreased by 18.4% under 40% mixing rate condition. To clarify the reason, effects of injection timing and period were evaluated with DOE method. Considering this result, optimization was done for these parameters. Also, comparison between performances of dual fueled engine and diesel engine was made after optimizing the timing of injection by DOE method. As a result, engine brake power was decreased by 8.55% under mixing rate 40% condition showing 12.5% improvement.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.54-58
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• 2007

The trailers with electronically controlled diesel engine was converted to dual fuel engine system. To estimate economical efficiency, test vehicles have been operated on a certain driving route repeatedly. Fuel economy, mximum driving distance per refueling and driveability are examined on the road including a free way. Developed vehicle can be operated over 500 km with dual Hel and shows 85% of diesel substitution ratio. Driveability is similar with but passing acceleration. It will be improved by calibration process. Test engine was set up for investigating power output, thermal efficiency and emission. ND 13-mode tests were performed for the test cycle. The emission result of dual fuel meets K2006 regulation and the engine performance of dual fuel engine was equivalent to the performance of diesel engine.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.28-33
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• 2015

In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.1-7
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• 2015

An ammonia fuel system is developed and applied to a 1 liter gasoline engine to use ammonia as primary fuel. Ammonia is injected separately into the intake manifold in liquid phase while gasoline is also injected as secondary fuel. As ammonia burns 1/6 time slower than gasoline, the spark ignition is needed to be advanced to have better combustion phasing. The test engine showed quite high variation in the power output to lead high increase in THC emission with large amount of ammonia, that is, higher than 0.7 ammonia-gasoline fuel ratios.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.472-475
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• 2005

Genenrally, biogas contained methane contents of $40-75\%$, was made in anaerobic compost facilities, landfill site, etc. And it is very useful for gas engine as a fuel. So, many imported biogas engines for electrical generation, are installed and operating now at landfill sites and anaerobic compost facilites. And KIMM has studied on and developed biogas engines with the aids of engine maker and parts companies for several years. Some results are shown here.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.372-379
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• 2020

Ammonia-hydrogen dual-fuel engine is a way to reduce greenhouse gas emission because ammonia and hydrogen are carbon-free fuels. In ammonia-hydrogen dual-fuel engine, hydrogen is supplied to improve the combustion characteristic of ammonia. In this study, an ammonia reformer was developed to supply hydrogen for 10 kW class ammonia-hydrogen dual-fuel engine. Thermodynamic characteristic and catalyst were investigated for ammonia reforming. Heat transfer was important for high ammonia conversion of ammonia reformer. 99% of ammonia conversion was obtained when 10 LPM of ammonia and 610℃ of hot gas were supplied to the ammonia reformer.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.43-49
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• 2016

In this paper, purpose of study is emissions characteristics according to effects of heating value variations of CNG fuel in a dual-fuel engine fueled by diesel and natural gas. For heating value variation of CNG fuel, nitrogen gas was mixed with pure CNG fuel. So the higher heating value was changed from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$. Under one condition of CNG substitution rate was fixed at 80%, diesel fuel was injected at a fixed injection timing of 16 CAD BTDC and fuel pressure was also fixed at 110 MPa. The condition of tested engine was 1800 rpm and 500Nm. Emissions were sampled in exhaust pipe was located at downstream turbocharger. As a result, emissions characteristics were checked in heating value variations of CNG fuel with mixed nitrogen gas THC, $CH_4$ and CO emissions decreased and NOx and $CO_2$ increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.700-707
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• 2017

In the international natural gas market, natural gas has markedly low calories. The domestic calories standard of natural gas was changed and the performance and efficiency of many industrial machines using natural gas were affected because of low caloric natural gas. Therefore, in this study, a dual fuel engine fueled with natural gas and diesel was tested to examine the effects of the CNG substitution rate on the combustion characteristics, such as thermal efficiency, COVimep and heat release rate. The CNG substitution rate was defined as the ratio of CNG instead of diesel, which was calculated as the total energy. The conditions of the tested engine were fixed $1800rpm/500N{\cdot}m$. In addition, diesel fuel was injected at $16^{\circ}CA$ BTDC and the fuel pressure was fixed at 85 MPa; the lower heating value of CNG was $10,400kcal/Nm^3$. The results of the engine test showed that the amount of diesel fuel was changed according to the CNG substitution rate. Therefore, when the substitution rate was increased, the amount of diesel fuel was decreased, which affected the energy for ignition. In addition, the ignition delay duration was increased, which affected the thermal efficiency and torque. On the other hand, the COVimep was less than 5% and a stable combustion state of the engine was shown.