• Current Optics and Photonics
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• v.8 no.2
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• pp.170-182
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• 2024

The dimensional accuracy and consistency of a dual oil circuit centrifugal fuel nozzle are important for fuel distribution and combustion efficiency in an engine combustion chamber. A point cloud measurement method was proposed to solve the geometric accuracy detection problem for the fuel nozzle. An improved variance focus measure operator was used to extract the depth point cloud. Compared with other traditional sharpness evaluation functions, the improved operator can generate the best evaluation curve, and has the least noise and the shortest calculation time. The experimental results of point cloud slicing measurement show that the best window size is 24 × 24 pixels. In the height measurement experiment of the standard sample block, the relative error is 2.32%, and in the fuel nozzle cone angle measurement experiment, the relative error is 2.46%, which can meet the high precision requirements of a dual oil circuit centrifugal fuel nozzle.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.110-115
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• 2012

This study describes the characteristics of combustion and exhaust emission in the special engine applying a fuel reactivity controlled compression ignition (RCCI) concept with two different energizing type (solenoid and piezoelectric) injectors for diesel injection. A diesel-gasoline mixed dual-fuel reactivity controlled compression ignition concept is demonstrated as a promising method to achieve high thermal efficiency and low emission in internal combustion engines for transportation vehicles. For investigating the combustion characteristics of RCCI, engine experiments were performed in a light-duty diesel engine over a range of injection timing and mixing rate of gasoline in mass. It was investigated that by increasing the nozzle hole diameter, increasing the combustion pressure and the net indicated mean effective pressure. $NO_x$ and soot can be reduced by advancing start of injection in 84 mixing rate of gasoline in mass. The resulting operation showed that light duty engine could achieve 48 percent net indicated efficiency and 191[g/kW-hr] net indicated specific fuel consumption with lower levels of nitrogen oxides and soot.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.29-34
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• 2011

This study investigates the potential of DME/Diesel dual fuel engine for reducing emissions with same power. Dual fuel engine controls the combustion using two different fuels, DME and diesel with different auto-ignition timings. In the previous work, the caracteristics of combustion and emissions under single cylinder engine and ignition is done by compression ignition. Pre-mixture is formed by injecting low-pressure DME into an intake manifold and high-pressure fuel (diesel or DME) is injected directly into the cylinder. Both direct diesel injection and port fuel injection reduced the significant amount of Smoke, CO and NOx in the homogeneous charge compression ignition engine due to present of oxygen in DME. In addition, when injecting DME directly in cylinder with port DME injection, there is no changes in emissions and energy consumption rate even operated by homogeneous charge compression ignition.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.148-153
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• 2008

As the oil price is dramatically jumping up, the consumption of LNG is rapidly expanding and the size of LNG carriers becomes bigger. For LNG ships, the application of DF (Dual-Fuel) engines gradually increases because of high efficiency, which alternatively use diesel or BOG (Boil-Off Gas) from cargo tank as a fuel. The surplus BOG from LNG cargo tank should be exhausted by GCU or liquefied through the BOG reliquefaction system and returned back. This study focused into its operational characteristics through the process simulation using HYSYS and discussed details on the influence of the variations of some operational parameters such as a distribution ratio by the change of fuel mass flow into the DF engine.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.270-273
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• 2012

These studies were conducted to determine the effects of various concentrations of ammonium and nitrate on current generation using dual-cathode microbial fuel cells (MFCs). Current generation was not affected by ammonium up to $51.8{\pm}0.0$ mg/l, whereas $103.5{\pm}0.0$ mg/l ammonium chloride reduced the current slightly. On the other hand, when $60.0{\pm}0.0$ and $123.3{\pm}0.1$ mg/l nitrate were supplied, the current was decreased from $10.23{\pm}0.07$ mA to $3.20{\pm}0.24$ and $0.20{\pm}0.01$ mA, respectively. Nitrate did not seem to serve as a fuel for current generation in these studies. At this time, COD and nitrate removal were increased except at $123{\pm}0.1$ mg ${NO_3}^-/l$. These results show that proper management of ammonium and nitrate is very important for increasing the current in a microbial fuel cell.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.147-148
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• 2014

This article describes an investigation of flame stability characteristics with various compositions of synthetic natural gas (SNG) in dual swirl combustor. The objective of this study is to investigate the flame stabilization, flame structure, fuel compatibility using chemiluminescence measurement in SNG with varying fuel compositions. As experimental conditions, hydrogen content was adjusted from 0 to 11%. Experimental results show that the addition of hydrogen has a major effect on flame behavior due to the higher burning rates associated with hydrogen consequently, The higher reaction activity of hydrogen has extended lean blow-off limit. Especially, DI flame limit has improved more 12.1%.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.95-100
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• 1999

One of the unsolved problems of the natural gas dual fuel engine is that there is too much exhaust of Total Hydrogen Carbon(THC) at a low equivalent mixture ratio. To fix it, a natural gas mixed with hydrohen was applied to engine test. The results showed that the higher the mixture ratio of hydrogen to natural gas, the higher the combustion efficiency. And when the amount of the intake air is reached to 90% of WOT, the combustion efficiency was promoted. But, like a case making the injection timing earlier, the equivalent mixture ratio for the nocking limit decreases and the produce of NOx increases.

• Journal of ILASS-Korea
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• v.27 no.2
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• pp.101-108
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• 2022

Performance and emissions with different diesel injection methods were analyzed in a natural gas-diesel, dual-fuel engine under low-load conditions. Natural gas was supplied to intake port during the intake stoke to form a natural gas-air premixed mixture for all methods. Diesel was injected directly into the cylinder during the compression stroke in three ways: early injections, late injections, and a combination of early and late injections. The early injections had the highest thermal efficiency among the three methods owing to its highest combustion efficiency. The wide dispersion of diesel before the combustion initiation also allowed superior emissions characteristics.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.273-275
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• 2014

An ammonia fuel system is developed and applied to both a spark ignition engine and a compression ignition engine to use ammonia as primary fuel in this study. Ammonia is injected separately into the intake manifold in liquid phase while gasoline or diesel is also injected as secondary fuel. As ammonia burns 1/6 time slower than gasoline or diesel, the spark or diesel injection timing is needed to be advanced to have better combustion phasing. The test engine showed quite high variation in the power output with large amount of ammonia. The final goal of the study is to implement a methodology to ignite ammonia-air mixture and have complete combustion without any use of the conventional fuels.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.161-165
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• 2007

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells. In addition they can be built as a self/non-reformable system and single/dual chamber system. So We evaluated some types of SOFC theoretically, and compared the results from the fuel and performance efficiency point of view.