• Journal of ILASS-Korea
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• v.9 no.1
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• pp.37-42
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• 2004

In a port fuel injection system of engine, a large part of fuel injected into an intake port adheres on its wall and inlet valve. Consequently, the wall impinging spray interaction might occur the generation of several harmful phenomena. There are uncontrollable mixture formation, an accidental backfire and unburned hydrocarbons. Therefore, it is important to analyze the fuel behavior during the spray-wall interaction. In this study, splash characteristics of impingement and reflecting or scattering behavior of droplets of fuel injected from EFI nozzle were studied experimentally. A test fuel used is LAWS and its physical characteristics are similar to the conventional gasoline except for the ignition point. Since the liquid film formed immediately after impinging on an impingement plate is unstable, it is easy to cause secondary disintegration. In addition, when the intermittently impingement on the impingement plate with LAWS, the splash ratio is around 0.6. If an injection period becomes longer, liquid film will become thick and the splash ratio will fall bout 10 percent. On the other hand, when the injection period of an intermittent spray is long, the same time lapse as a continuous spray is shown.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.71-75
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• 2010

This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by injection operating water to cooling plate. And at this experiment it used ethylene glycol-water solution and the concentration is 10 to 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank, brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring and a vertical circular tube with single copper plate as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 1.0 to 2.0m/s and the cooling temperature of $-17^{\circ}C$ to $-10^{\circ}C$.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.443-452
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• 2005

The purpose of this study is experimentally to analyze the effects of intake port swirl, injection system and turbocharger on the engine performance and the emission characteristics in a V8 type turbocharger intercooler D.I. diesel engine of the displacement 16.7L, and to suggest the improvement of engine performance. Generally to enhance engine power, TCI diesel engine is put to practically use turbocharged intercooler in order to increase volume efficiency which is cooled boost air. As results of considering the factors of the intake port of swirl ratio 2.25, compression ratio 17.5. re-entrant $8.5^{\circ}$ combustion bowl, nozzle hole diameter ${\phi}0.33{\ast}3+{\phi}0.35{\ast}2$. nozzle protrusion 3.18mm, injection timing BTDC $12^{\circ}CA$ and turbocharger(compressor 0.6A/R+46Trim. turbine 1.0 A/R+57Trim) is the best in the full load in the engine performance and the exhaust characteristics of NOx concentration. Therefore. their factors are appropriated as intake system, injection and turbocharger system.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.2
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• pp.9-18
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• 2000

Combustion and emission characteristics in a direct injection diesel engine is closely related to the intake port system. It is therefore important to understand the swirl flow characteristics formed by a helical intake port. However there are still many uncertainties. The purpose of this experimental study is to investigate the effects of the valve eccentricity ratio and the inlet flow conditions of a helical intake port on the characteristics of an in-cylinder swirl flow. A steady state flow test rig consisted of ISM(impulse swirl meter), LFM(laminar flow meter) and cylinder head with a helical intake port was used. The swirl ratio(Rs) and mean flow coefficient(Cf(mean)) with inlet flow conditions were measured. The results of these experiment can be summarized as follows. Swirl flow characteristics of a helical intake port are affected by the inlet flow conditions, and especially they are much affected by the length of a manifold runner and the rotational angle of a curved manifold runner.

• Analytical Science and Technology
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• v.34 no.2
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• pp.68-77
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• 2021

Cannabis is one of the most abused drugs in Korea. The main psychoactive component in cannabis, Δ9-tetrahydrocannabinol, is metabolized to 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) and THCCOOH-glucuronide (THCCOOH-glu) in the human liver, whereby the amount of THCCOOH-glu found in urine is twice as high as that of THCCOOH. The analytical process adapted by the majority of urine drug-testing programs involves a two-step method consisting of an initial immunoassay-based screening test followed by a confirmatory test if the screening test result is positive. In this study, a qualitative gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the detection of THCCOOH in human urine, where THCCOOH-glu was converted into THCCOOH by alkaline hydrolysis. For purification of the urine extract prior to instrumental analysis, high-speed centrifugation was used to minimize interference. In addition, an injection-port derivatization method using ethyl acetate and N,O-bis(trimethylsilyl)-trifluoroacetamide containing 1 % trimethylchlorosilane was employed to reduce the time required for derivatization, and an aliquot of the final solution was injected into the GC-MS. The method was validated by measuring the selectivity, limit of detection (LOD), and repeatability. The sensitivity, specificity, precision, accuracy, Kappa, F-measure, false positive, and false negative rate were determined by comparing the GC-MS results with those obtained using the immunoassay. The LOD was determined to be 0.32 ng/mL, while the repeatability was within 9.1 % for THCCOOH. Furthermore, a comparison study was carried out, whereby the screening immunoassay exhibited a sensitivity of 86.4 % and a specificity of 100 % compared to GC-MS. The applicability of the developed method was examined by analyzing spiked urine and forensic urine samples obtained from suspected cannabis abusers (n = 221).

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.9-21
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• 2000

In this study, the characteristics of high-pressure swirl injector have been studied using a commercial CFD code, STAR-CD and experiment to investigate the effect of the length of orifice and swirl port on the spray characteristics. Influences of swirl port angle and initial conditions have also been examined in terms of penetration depth and Sauter`s mean diameter. Computed results of the spray characteristics are compared with experimental results. The results show that the tangential velocity at the nozzle exit decreases, but the axial velocity increases as swirl port angle is increased. Hence, the static flow rate increases, but the initial spray angle decreases with increasing the swirl port angle. It is also shown that the values of the initial SMD used as input data for spray simulation influences the penetration depth and SMD. The spray pattern from the present numerical simulation agrees well with experimental result.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.101-102
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• 2014

Rising oil price and environmental problems are causing automotive industry to increase fuel efficiency. Improved fuel efficiency in gasoline engine was made possible by development of DISI gasoline engine. Since fuel is injected inside cylinder directly, in-cylinder temperature can be reduced than multi-port injection engine and this leads to increased compression ratio. However, engine performance is largely dependent on mixture formation process due to in-cylinder fuel injection. Especially for spray guided and air guided DISI gasoline engine, injection direction is important factor to mixture preparation. It is because interaction between intake flow and spray affect fuel-air mixture. Hence, in this study, mixture formation characteristics were analyzed by varying injection direction using KIVA 3V release2 code. Residual gas was considered for assuming combustion. Therefore, initial condition for in-cylinder temperature was set equal to the end state of exhaust stroke of combustion cycle. Since angle between intake air flow direction and spray direction affects fluid flow and evaporation field, mixture distribution was affected by fuel injection direction dominantly.

• Journal of the Korean Society of Combustion
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• v.18 no.1
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• pp.7-12
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• 2013

A quasidimensional program is developed for a four stroke cycle homogeneous GDI (Gasoline Direct Injection) engine. It includes models for spray, burning rate and chemistry to predict knock and emissions. With early injection a homogeneous GDI engine goes through spark ignited, turbulent premixed combustion as in PFI (Port Fuel Injection) engines. The cylinder charge is divided into unburned and burned zone with the latter divided into multiple zones of equal mass to resolve temperature stratification. Validation is performed against measured pressure traces, NOx and CO emissions at different load and RPM conditions. Comparison is made between an empirical knock model and predictions by the chemistry model in this work.

• International Journal of Automotive Technology
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• v.1 no.1
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• pp.1-8
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• 2000

This paper reviews the main drivers forcing change and progress in powertrains for passenger cars in the coming years. The environmental drivers of omissions and CO2 will force better technical performance, but customer demand for increased choice will force change in the basic engine design and provide opportunities for alternate configurations of powertrain. Gasoline engines will embody refinements of valve train actuations as well as developments in combustion, especially direct injection and possibly a lean booated form of direct injection. Nevertheless, the conventional, port injected engine will continue to be the dominant engine for some years to come. The high speed direct injection diesel will very soon supplant its indirect injection predecessor completely. It will take an increasing share of the total powertrain market as improved specific power and refinement make it even more attractive to the customer. Car manufacturers will provide diesel models to satisfy this customer demand as well as using the efficiency of the diesel to enable them to meet their fleet CO2 commitments. Both gasoline and diesel engines will see an increasing degree of electrification and partial hybridisation as efficient flywheel mounted electrical devices become available.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.61-61
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• 2011

Cavitation phenomena during the injection process of the conventional fuel injection pump for a medium-speed diesel engine can cause surface damage with material removal or round-off on the plunger and barrel port and may shorten their expected life time. An experiment of flow visualization was carried out to investigate the main cause of these cavitation damages and find the prevention method. Experimental results of flow visualization show that these damages are mainly affected by fountain-like cavitation and jet-type cavitation generated before and after the end of fuel delivery process and therefore the prevention method was designed to control these cavitation flows. From the visualization and endurance test, it was proved that this method can effectively prevent cavitation damages by controlling cavitation flows.