• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.9
• /
• pp.165-171
• /
• 1999

An oil layer fuel absorption /desorption modeling was developed. Multi-component fuel model has showed more reasonable condition than single component model. Henry's constant which is related to solubility is the most important variable in the oil layer absorption/desorption mechanism. The oil segments close to the top of the cylinder liner have more significant contribution to the fuel absorption and desorption process than other oil segments. At the warmed-up condition, the effect of the engine speed on the precent fuel absorbed/desorbed is minimal. But at low il film temperature, percent of fuel abosrbed/desorbed is decreased with increasing the engine speed because of low value of molecular diffusion coefficient of fuel. The amount of fuel trapped in the piston crevice is from 2 to 2.3 times larger than that of fuel in the oil fim. However, fuel form oil film slowly desorbs into the combustion chamber compared with fuel from the piston crevices when the engines is cold.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.2
• /
• pp.187-194
• /
• 2001

Spray impingement and fuel film formation models were developed and incorporated into the computational fluid dynamics code. STAR-CD. The spray/wall interaction process was modeled by considering the change of behaviour with surface temperature conditions and the fuel film formation. We divided the behaviour of fuel droplets after impingement into rebound, spread and splash using the Weber number and the parameter K. The Spray impingement model accounts for mass conservation, energy conservation and heat transfer to the impinging droplets. The fuel film formation model was developed by integrating the continuity, Navier-Stokes and energy equations along the direction of fuel film thickness. Validation of the models was conducted using previous diesel spray experimental data and the present experimental results for the gasoline spray impingement. In all the cases, the prediction compared reasonably well with the experimental results. The spray impingement and fuel film formation models have been applied to the spray/wall impingement in high speed direct injection diesel engines.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.10
• /
• pp.1370-1376
• /
• 2003

The investigation of liquid fuel film on the cylinder liner is an essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to investigate the liquid fuel film on the quartz liner in the optical engine. For this, the optical engine with hydraulic system was designed based on the commercial SI engine. The visualization was based on the laser-induced fluorescence with total reflection technique. Using a quartz liner and a special lens, only the liquid fuel film on the liner was visualized. With using this technique, the distribution of the fuel film on the cylinder liner was measured for different engine conditions and injection timing in the optical engine.

• Journal of ILASS-Korea
• /
• v.2 no.4
• /
• pp.15-21
• /
• 1997

In a gasoline engine with port injection system, the fuel behavior in the intake port has significant influence on the HC emission and the precise A/F control. That is to say, it is inevitable that the injection direction and behavior of fuel injected in the intake port have an effect on the generation of unburned HC within a cylinder. In this paper, we visualized fuel behavior in the intake port using micro CCD camera synchronized with the stroboscope and investigated the fuel-film characteristics formed at the wall of intake port by processing image captured with VCR in the transparent intake port made of acryl. Using these measuring methods, it was found that fuel behavior and the formation of fuel-film in the intake port could be evaluated qualitatively. And results obtained by these methods show that 2-spray injector minimizes the fuel-film formed in the intake port of a DOHC gasoline engine.

• Journal of ILASS-Korea
• /
• v.23 no.1
• /
• pp.36-41
• /
• 2018

Fuel wall film effects power output and cycle deviation by changing the amount of fuel flowing into cylinder in PFI gasoline engines. Reduction of wall film can reduce fuel consumption and improve combustion stability. In this research, the effects of injection strategies including injection pressure and dual injection system is investigated for reducing wall film formation. The CONVERGE software is used for numerical analysis tool and O'Rourke film splash model was used for wall film prediction model. Compared with the reference case wall film decreased with increase of injection pressures, and the film formation reduced when the dual injection system was used.

• Journal of the Korean Ceramic Society
• /
• v.45 no.8
• /
• pp.472-476
• /
• 2008

The surface region of commercial stainless steel 304 and 316 plates has been modified through deposition of the multi-layered coatings composed of titanium film ($0.1{\mu}m$) and gold film ($1-2{\mu}m$) by an electron beam evaporation method. XRD patterns of the stainless steel plates deposited with conductive metal films showed the peaks of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The stainless steel plates modified with $0.1{\mu}m$ titanium film and $1{\mu}m$ gold film showed microstructure of grains of under 100 nm diameter. The external surface of the stainless steel plates deposited with $0.1{\mu}m$ titanium film and $2{\mu}m$ gold film represented somewhat grain growth of Au grains in FE-SEM image. The electrical resistance and water contact angle of the stainless steel bipolar plates modified with multi-layered coatings were examined with the thickness of the gold film.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.643-645
• /
• 2008

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1um) and gold film (1-2um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed microstructure of grains of about 100nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.251-253
• /
• 2017

Numerical study of air-blast type injector for low emission aircraft engines was conducted. Volume-of-fluids approach was used to track interface of fuel and air. Primary atomization of fuel stream was visualized, and thickness and mean velocity at the injector exit was calculated. Liquid fuel injected from fuel slots joined together as a thin film on preflimer surface, and interacted with swirling air. As instability on the fuel surface increased, separation of fuel as ligaments and droplets occured. The film thickness and velocity were used to as fuel injection boundary condition for reactive flow simulation. Primary reaction zone was formed in vicinity of the fuel nozzle, creating a stable flame inside the combustor.

• 한국전기화학회:학술대회논문집
• /
• 2000.04a
• /
• pp.37-37
• /
• 2000

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.646-648
• /
• 2008

The multi-films of a metallic film and a transparent conducting oxide (TCO, indium-tin oxide, ITO) film were formed on the stainless steel 316 and 304 plates by a sputtering method and an E-beam method and then the external metallic region of the stainless steel bipolar plates was converted into the metal nitride films through an annealing process. The multi-film formed on the stainless steel bipolar plates showed the XRD patterns of the typical indium-tin oxide, the metallic phase and the metal substrate and the external nitride film. The XRD pattern of the thin film on the bipolar plates modified showed two metal nitride phases of CrN and $Cr_2N$ compound. Surface microstructural morphology of the multi-film deposited bipolar plates was observed by AFM and FE-SEM. The electrical resistivity of the stainless steel bipolar plates modified was evaluated.