• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.1
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• pp.41-48
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• 1986

Ifis recommended that the injection rate should be accurate and reliable in the input data of the performance simulation in diesel engine. Matsuoka Sin improved W. Bosch's injection ratio measurement system. Matsuoka Sin reduced length of the test pipe and set the orifice. However, it was not measured accurately to measure the injection ratio due to reflection wave. In the present thesis, the improved measurement system with combination of the conventional W. Bosch type injection ratio measurement system and Matsuoka Sin type corrected W. Bosch type was practically made. The location of orifice and throttle valve was modified and set one more back pressure valve in order to reduce the effect of reflection wave. The results according to injection condition of multi-hole nozzle are following: 1. Measurement error of injection ratio measurement system in this thesis was $\pm$ 1 %, therefore, its reliability was good. 2. The form of injetion ratio is changed from trapezoidal shape to triangle shape with increase of revolution per minute when injection amount is constant. 3. In the case of constant rpm, the initial injection ratio is almost constant regardless of the amount, meanwhile the injection period becomes longer with increase of the amount. 4. The injection pressure of nozzle isn't largely influenced with injection ratio in the case of constant injection amount and rpm, otherwise the initial injection amount is increased by 3-4% when the injection pressure is low. 5. The injection ratio isn't nearly influenced with back pressure.

• Journal of ILASS-Korea
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• v.20 no.4
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• pp.217-222
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• 2015

In this study, Injection rate tests of a Diesel common-rail injector have been performed with injection volume measurement type injection rate test system EMI21 for construction of injector model can be used in an engine calibration mean valued model. The measuring principle of the test system is based on measurement of dispalcement of a movable measurement piston by the volume of fluid released by the injector. From these injection rate test results, the characteristics on shape of instantaneous injection rate and injection fuel amount have been investigated and injection fuel amount calculation equation based on test results has been newly constructed. This equation is very simple and calculation error is less than 5% with test results for wide range injection pressure (200~1800 bar) and injection duration ($200{\sim}1800{\mu}s$) conditions. So, it is anticipated that newly constructed simple injection fuel amount model in this study can be efficiently used on engine calibration and control model.

• Journal of ILASS-Korea
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• v.26 no.2
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• pp.96-103
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• 2021

In order to improve the overall efficiency and meet the emission regulations of boiler systems, the heat exchanging methods between inlet air and exhaust gas have been used in boiler systems, named as the waste-heat-recovery condensing boiler. Recently, to further improve the overall efficiency and to reduce the NOx emission simultaneously, the concept of the water injection into the inlet air is introduced. This study suggests the models for the optimized design parameters of water injection for waste-heat-recovery condensing boilers and performs the analysis regarding the water injection amount and droplet sizes for the optimized water injection. At first, the required amount of the water injection was estimated based on the 1^st law of thermodynamics under the assumption of complete evaporation of the injected water. The result showed that the higher the inlet air and exhaust gas temperature into the heat exchanger, the larger the amount of injected water is needed. Then two droplet evaporation models were proposed to analyze the required droplet size of water injection for full evaporation of injected water: one is the evaporation model of droplet in the inlet air and the other is that on the wall of heat exchanger. Based on the results of two models, the maximum allowable droplet sizes of water injection were estimated in various boiler operating conditions with respect to the residence time of the inlet air in the heat exchanger.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.193-201
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• 2014

A numerical study has been carried out to analyze the combustion characteristics in heavy duty diesel engine with post injection for reducing NO emission. For verification of numerical study results, calculated cylinder pressure was matched to experimental data. In this study, post injection timing and amount of post injection were modified as parameters, but the total amount of injection fuel was maintained. As the results, maximum cylinder pressure increases above minimum 2% by post injection and end of pressure curve is decreased rapidly. The more dwell time and amount of post injection fuel are, the more pressure drop occurs. And trade-off relation of NO and soot are appeared. In the results, NO was reduced without deterioration of cylinder pressure under condition of $10^{\circ}$ CA dwell time and main 60%, post 40% fuel portion.

• Journal of ILASS-Korea
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• v.18 no.1
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• pp.55-60
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• 2013

In this study, injection flow rates and material of the solenoid sealing of the injectors were improved for the development of a di-methyl Ether(DME) common-rail system. To deliver the same amount of energy provided by injection pressure of diesel $P_{inj}$ = 160 MPa, the DME injectors need to have larger diameter of nozzle hole and more No. of hole at low injection pressure of $P_{inj}$ = 40~50 MPa. The simplified nozzle flow model, which takes account of nozzle geometry and injection condition, was employed in order to design the concept of a injector nozzle such as No. of hole, diameter of hole and diameter of needle seat, etc. Injection amount and rate were tested by diesel and DME test stand. As a result, the diameter of nozzle hole were enlarged by 0.25 mm. The diameter of the orifice in the high pressure line was increased by 1.0 mm to maintain hydraulic force in the nozzle. The material of the solenoid sealing was changed to HNBR, which was strong against the corrosive. Experimental results showed that the injection amount of the DME injector drastically increased by 191.9% comparison to that of diesel at $P_{inj}$ = 40 MPa.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.55-64
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• 2014

This work was investigated on pilot injection strategy of blended fuels(Diesel-DME) for combustion and emissions in a single cylinder direct injection compression ignition engine. Diesel and DME were blended by the method of weight ratio. Weight ratios for diesel and DME were 95:05 and 90:10 respectively. dSOI between main and pilot injection timing was varied. A total amount of injected fuels(single injection) was adjusted to obtain the fixed BMEP as 4.2 bar in order to compare with the fuel conditions. Also, the amount of pilot injection fuel was varied by 5%, 10% and 20% of total injection fuel. The engine was equipped with common rail and injection pressure is 700 bar at 1200 rpm. As a result, when mixing ratio increase, indicated thermal efficiency was increased in comparison with DD 100 and CO, THC and smoke were lower than DD 100. The influence of reducing NOx by pilot injection was more effective than DD 100. When pilot injection quantity increase, abrupt increase of NOx was occured at pilot injection quantity of 20%.

• Journal of ILASS-Korea
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• v.22 no.2
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• pp.87-95
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• 2017

Recently, as the interest in environmental issues have increased around the world, the regulation on vehicle exhaust have been tightened in each country. To satisfy such tightened exhaust regulation, automotive manufactures are forced to equipped Diesel Particulate Filter (DPF) at Diesel vehicles. If DPF is used for a long time, DPF regeneration should be performed. The objective of this study is to research on post injection for DPF regeneration. The result of the study was that it was desired that retarding post injection timing, lower load of engine and smaller the amount of main fuel injection, for DPF regeneration. Oil dilution was tended to increase as load was lower, amount of post injection was increased, and post injection timing was retarded.

• Journal of ILASS-Korea
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• v.28 no.1
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• pp.43-48
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• 2023

The waste-heat-recovery boiler with water spray (HR-B/WS) applies the heat exchange between the inlet air and exhaust gas with the water spray into the inlet air. The evaporation of water in the inlet air promotes heat recovery from the exhaust gas so that thermal efficiency can be improved by the enhanced condensing effect. The NOx emission can also be reduced by lowering the flame temperature due to the dilution effect of the water. In this study, the validity of this concept is examined by the practical boiler test performed with a 24 kW condensing boiler under the full load condition according to the water injection amount. The theoretical amount of water injection is calculated under the assumption of full evaporation of the sprayed water, which is calculated as 50 g/min. Since the injected water cannot evaporate fully in the actual system, the maximum water spray amount is set as 100 g/min. The results showed that the water injection can increase the thermal efficiency up to 95.59% and reduce NOx and CO emissions simultaneously to 8.9 ppm and 35 ppm at 0% of O₂. Although the heat energy loss increased due to the unevaporated water, the increase in water injection amount caused higher thermal efficiency due to the increased amount of the evaporated water.

• Journal of ILASS-Korea
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• v.11 no.4
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• pp.228-233
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• 2006

There are two types of electric controlled fuel injection system in the gasoline engines of common vehicles. One is fuel return system and the other is fuel returnless system according to the methods of controlling injection pressures. It is important to understand the characteristics of these system in loaming and studying of engine, but it is very difficult without a special equipment in reality. The purpose of this paper is to develop the emulation system that can be compensated with the amount of injection fuel according to various driving conditions, battery voltage, cooling water temperature, and engine speed, may be appeared in real driving, and especially can analyze the difference between the electric signal controlling the amount of injection fuel and its result, and nullity injection duration. With the developed system, we can conveniently set various and completed driving condition and so can acquire the useful information such as non-uniformity rate and mass of injection fuel using waveform analysis and measurement modules. It must be a very useful and sophisticated system to instruct and learn the features and operating states of injection system, and to study f3r improving the performance of it.

• Archives of Craniofacial Surgery
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• v.25 no.1
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• pp.17-21
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• 2024

Background: The pain caused by local anesthetic injection can lead to patient anxiety prior to surgery, potentially necessitating sedation or general anesthesia during the excision procedure. In this study, we aim to compare the pain relief efficacy and safety of using a digital automatic anesthetic injector for local anesthesia. Methods: Thirty-three patients undergoing excision of a benign soft tissue tumor under local anesthesia were prospectively enrolled from September 2021 to February 2022. A single-blind, randomized controlled study was conducted. Patients were divided into two groups by randomization: the experimental group with digital automatic anesthetic injector method (I-JECT group) and the control group with conventional injection method. Before surgery, the Amsterdam preoperative anxiety information scale was used to measure the patients' anxiety. After local anesthetic was administered, the Numeric Pain Rating Scale was used to measure the pain. The amount of anesthetic used was divided by the surface area of the lesion was recorded. Results: Seventeen were assigned to the conventional group and 16 to the I-JECT group. The mean Numeric Pain Rating Scale was 1.75 in the I-JECT group and 3.82 in conventional group. The injection pain was lower in the I-JECT group (p< 0.01). The mean Amsterdam preoperative anxiety information scale was 11.00 in the I-JECT group and 9.65 in conventional group. Patient's anxiety did not correlate to injection pain regardless of the method of injection (p= 0.47). The amount of local anesthetic used per 1 cm² of tumor surface area was 0.74 mL/cm² in the I-JECT group and 2.31 mL/cm² in the conventional group. The normalization amount of local anesthetic was less in the I-JECT group (p< 0.01). There was no difference in the incidence of complications. Conclusion: The use of a digital automatic anesthetic injector has shown to reduce pain and the amount of local anesthetics without complication.