• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.37-43
• /
• 2003

The objective of this work is to investigate the effect of swirl, injection pressure and pilot injection on D.I. diesel combustion by using a transparent engine system. The test engine is equipped with common rail injection system to obtain high pressure and to control injection timing and duration. In this study, the combustion analysis and steady flow test were conducted to estimate the heat release rate from in-cylinder pressure. Soot distribution in diffusion flame according to swirl ratio, injection pressure and pilot injection was investigated by using LII technique. As the results, high injection pressure was found to shorten ignition delay as well as enhance peak pressure and heat release rate was greatly affected by injection timing and pilot injection. In addition, the results showed that the period of soot formation corresponded to the diffusion flame.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.10
• /
• pp.1435-1441
• /
• 2003

Combustion characteristics on diesel-water emulsion are analyzed in high pressure injection for several variables such as water content, injection pressure and injection timing. As a fact of well-known, maximum combustion pressure was decreased and ignition delay was elongated in accordance with increasing of water content. But these characteristics were enhanced with increase of injection pressure to high pressure. It was shown that combustion of neat diesel in case of injecting with 600bar is similar to that of 20 % diesel-water emulsion was injected at 1200 bar.

• Journal of Mechanical Science and Technology
• /
• v.17 no.9
• /
• pp.1371-1379
• /
• 2003

The effects of change in injection pressure on spray structure in high temperature and pressure field have been investigated. The analysis of liquid and vapor phases of injected fuel is important for emissions control of diesel engines. Therefore, this work examines the evaporating spray structure using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 22 MPa to 112 MPa using a high pressure injection system (ECD-U2). Also, we conducted simulation study by modified KIVA-II code. The results of simulation study are compared with experimental results. The images of liquid and vapor phase for free spray were simultaneously taken by exciplex fluorescence method. As experimental results, the vapor concentration of injected fuel is leaner due to the increase of atomization in the case of the high injection pressure than in that of the low injection pressure. The calculated results obtained by modified KIVA-II code show good agreements with experimental results.

• Journal of the Korean Society of Safety
• /
• v.27 no.1
• /
• pp.49-54
• /
• 2012

The objective of this study is to investigate the capacity of epoxy injection method using low pressure mixed with high pressure. Injection depth test and flexural strength test were respectively performed on $40{\times}45{\times}35$ cm and $100{\times}10{\times}40$ cm specimens. Considered as the test variables were injection type(low pressure, low and high pressure), crack width(0.25 mm, 0.50 mm), injection direction(upper, lower, side), and epoxy viscosity(low, medium, high). Test results showed that low viscosity epoxy injection depth of injector using low pressure mixed with high pressure for upper direction were 23 cm and tension strength of crack face repaired by injector using low pressure mixed with high pressure was larger than that of concrete.

• Journal of ILASS-Korea
• /
• v.20 no.1
• /
• pp.43-52
• /
• 2015

Experimental study was conducted to investigate the effects of ultra-high injection pressure and nozzle hole diameter on diesel flow and spray characteristics. Electronically controlled ultra-high pressure fuel injection system was made to supply the fuel of ultra-high pressure consistently. Three injection pressures, 80, 160, and 250MPa were applied. Four type of injectors with identical eight nozzle holes were used. The four injectors have nozzle hole diameters of 115, 105, 95, and $85{\mu}m$ respectively. Injection quantity and rate were measured to investigate flow characteristics according to injection pressures and nozzle hole diameters. Mie-scattering and shadowgraph were performed to visualize liquid and vapor phases of diesel spray in a constant volume combustion chamber (CVCC). Ambient conditions of high pressure and high temperature in a diesel engine were simulated by using CVCC.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.6
• /
• pp.43-52
• /
• 2000

In this study, a simulation program was developed, which could simulate a fuel injection system for low-speed marine diesel engine. The fuel injection system was divided into fuel injection pump, high pressure pipe and fuel injection valve. The unsteady flow in the high pressure injection pipe was analyzed by the method of characteristics, considering cavitation and variation of fuel density and bulk modulus. It was confirmed that the simulation results were good agree with experimental results of injection pressure and quantity at the high pressure distributor in fuel injection system for the training ship "M/V Hannara". And the effects of the atomizer hole diameter, maximum needle lift, plunger diameter and nozzle opening pressure were also investigated with simulating results.g results.

• Journal of ILASS-Korea
• /
• v.16 no.1
• /
• pp.7-14
• /
• 2011

High pressure LPG fuel spray with a conventional swirl injector was visualized and the impact of the injection pressure was also investigated using a DISI (direct injection spark ignition) LPG single cylinder engine. Engine performance and emission characteristics were evaluated over three different injection pressure and engine loads at an engine speed of 1500 rpm. The fuel spray pattern appeared to notably have longer penetration length and narrower spray angle than those of gasoline due to its lower angular momentum and rapid vaporization. Fuel injection pressure did not affect combustion behaviors but for high injection pressure and low load condition ($P_{inj}$=120 bar and 2 bar IMEP), which was expected weak flow field configuration and low pressure inside the cylinder. In terms of nano particle formation the positions of peak values in particle size distributions were not also changed regardless of the injection pressure, and its number densities were dramatically reduced compared to those of gasoline.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.302-305
• /
• 2007

In recent years, many researches on new storage media with high capacity and information are developing. For manufacture of optical storage with high capacity, the injection molding process is generally used. In order to increase the filling ratio of the injection molding structure, the injection molding process required for high injection pressure, packing pressure and temperature control of the mold. However, conventional injection molding process is difficult to increase the filling ratio using injection master with the range of several nanometers and high aspect ratio. In order to improve and increase filling ratio of nano-structure with high aspect ratio, the active temperature control of injection mold was used. Experimental conditions were used injection pressure, time and temperature. Consequently, by using the peltier device into injection mold, we carried out the efficient and active temperature control of mold at low cost.

• Journal of Advanced Marine Engineering and Technology
• /
• v.27 no.1
• /
• pp.57-64
• /
• 2003

The characteristics of fuel spray have an important effect on engine performance such as power, specific fuel consumption and emission because fuel spray controls the mixing and combustion process in an engine. Therefore, if the characteristics of fuel spray can be measured, they can be effectively used for improving engine performance. The major factors controlling fuel spray are injection pressure, ambient pressure and engine speed. In this study, the experiment is performed in a high temperature and high pressure chamber. In experiments, spray tip penetration, spray angle and spray tip velocity are measured at various injection pressure (10 and 14 MPa), ambient pressure(3,4 and 5 MPa), fuel pump speed(500, 700 and 900 rpm). Experimental results are useful for deriving an experimental spray equation and design an optimal engine. The results showed that injection pressure, ambient pressure and fuel pump speed are important factors influencing on the characteristics of spray. 1) Injection pressure influences on the characteristics of spray. That is, as injection pressure is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle and spray penetration are increased as fuel pump speed is increased.

• Archives of Plastic Surgery
• /
• v.37 no.3
• /
• pp.245-249
• /
• 2010

Purpose: High-pressure injection injury is caused by accidental injection of the high-pressure injection devices in industry. The initial benign appearance of the wound fools patients into delays in an adequate treatment. And it can result in disastrous outcomes such as necrosis and amputation. To avoid the poor prognosis, the injuries require a prompt surgical intervention. The purpose of this article is to recognize the poor outcome of the highpressure injection injury and to introduce an adequate treatment in need. Methods: We have 4 cases of the high-pressure injection injuries in the hand from April, 2005 to March, 2009. Average age is 39 years (30 - 49 years old), 2 cases are the palm of dominant hand, 1 case is the thumb of dominant hand, and 1 case is the palm of non-dominant hand, respectively. We followed up these patients for 20 months on average. In 3 cases, the immediate, aggressive surgical intervention was carried out, but the other one was delayed in early adequate treatment. The wounds were covered by local advancement flap, anterolateral thigh free flap, conservative treatment with antibiotics and dressing. Results: No pathogens after culture were found nor any findings of fracture in imaging study. Conservative treatment, local advancement flap and anterolateral thigh free flap for the open wound resulted in a desirable aesthetic outcome. In a long-term follow up, functional capability of the patient was also satisfactory. Conclusion: Upon initial evaluation, most high-pressure injection injuries present as innocuous wounds with very few symptoms and result in delaying the proper management. And the majority of high-pressure injection injuries will produce significant morbidity to the hand, amputation. And the initial aggressive surgical debridement was needed to prevent the poor outcome. The key to success in treating high-pressure injection injuries of the hand is the prompt aggressive surgical intervention.