• Journal of the korean Society of Automotive Engineers
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• v.16 no.6
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• pp.16-21
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• 1994

본 연구에서는 연료의 핵심기술인 분사기술을 향상시키기 위하여 연료의 고압분사와 초음파 에너지 공급기술을 이용하여 연료의 미립화를 시도하고 EFI연료 분사방식에서 초음파 공급장치를 개발하여 추후 직접 분사식 초음파 무화장치의 개발을 위한 기초를 마련하고 직접 분사식에서 문제시되어지는 분사 초기 또는 분사 말기의 분사연료 미립화의 분사 전구간에서의 분사연료의 미립화를 시도하기 위한 기초를 마련하고자 한다.

• Bulletin of Food Technology
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• v.11 no.2
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• pp.70-78
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• 1998

공기와 같은 유체를 식품의 표면에 직접 고압으로 분사하는 것은 그 식품을 가열하거나, 건조, 냉각, 냉동시키는데 큰 도움을 주고 있다. Impingement-분사(공기, 스팀), 조사(방사선, 레이저), 침투(당액, 냉매) 등의 식품가공기술 기술은 우리가 생활하고 있는 주변에서 일상적으로 나타는 현상이다. 지표면에 태양빛이 전달되는 것이나 상점에서 물건구입시 포장지에 붙은 바코드(barcode)에 레이저빔을 쏘는 것도 모두 Impingement현상이다. 레이더도 전자파를 발사하는것(Impinging)이며, 배나 잠수함도 음파를 발사하여 장애물을 탐지하면서 운항한다. 세차장에서 차를 세차하는 것도 고압의 물을 분사(Impinging)하는 기술이 동원 되는 것이다. Impingement 방식에 의해 식품을 가열하거나 냉각하는 것은 기존의 방법들보다 속도는 느리지만 그만한 값어치가 있는 유용한 식품가공 기법이다.

• Journal of ILASS-Korea
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• v.15 no.1
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• pp.25-30
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• 2010

The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for driving the injector.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.2
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• pp.279-284
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• 2013

In this paper, to evaluate the performance of solenoidal typed injector, research and development had been performed on injector controller in order to respond to various performance tests, which is not only economical but easy extensible on its channels. The developed controller based on embedded system is able to precisely control the injection timing and quantity by high-pressured from the injector. Also, it is able to performance evaluation by measuring the electrical characteristics of solenoid. Additionally, it is enable precision timing control of light source and high speed camera as it is able to precisely photograph the timely spray pattern of injector.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.3
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• pp.107-117
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• 2000

Ball poppet valve type high pressure hydrogen injection valve actuated by solenoid has been developed for the feasibility of practical use of hydrogen fueled engine with direct injection and the precise control of fuel injection ratio in hydrogen fueled engine with dual injection. The gas-tightness of ball poppet injection valve is improved by the introduction of ball-shaped valve face, valve end typed spherical pair, and valve stem with rotating blade. Ball poppet valve is mainly closed by differential pressure due to the area difference between valve fillet and pressure piston. So, it can be operated by solenoid actuator with small driving force. From the evaluation of ball poppet injection valve, it was found that the gastightness and controlment of this injection valve are better than those of injection valve had been developed before.

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.67-73
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• 2010

The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for injector driving.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.181-187
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• 2008

Recently, alternative fuels are drawing more attentions due to the increasing need for lower emission characteristics and fuel consumption rate in automotive engines. The GTL(gas to luquid) is the one of most favored candidates. It has higher cetane number(more than 75) and almost negligible sulphur and aromatic contents. Therefore, enhanced emission characteristics are expected even in the application in diesel engines without any modification. In this study, the cylinder pressure and heat release, emission characteristics with fuel injection timings are compared between diesel and GTL fuel in the single cylinder diesel engine. Noticeable reduction in PM, THC and CO emission are observed due to lower sulphur and aromatic contents in GTL. Also, the ignition delay decreased due to higher cetane number of GTL, which slightly decreased the amount of NOx emissions. With the retards of main injection timing, NOx decreases more for the case of GTL, while the level of THC and CO emissions still remains lower than the case of diesel. Therefore, there is much room for the control of injection timing for NOx reduction without sacrificing THC and CO emissions. With the retards of main injection timing, Small size distribution of PM became lager and there amount increased. But from all conditions, size distribution of PM for the case GTL was lower than Diesel.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.90-96
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• 2019

Natural gas has been regarded as one of major alternative fuels, because of the increment of mining shale gas and supplying PNG(Pipeline Natural Gas) from Russia. Thus, it needs to broaden the usage of natural gas as the increasing its supplement. In this situation, application of natural gas on the transport area is a good suggestion to reduce exhaust emissions such as CO₂(carbon dioxides) and soot from vehicles. For this reason, natural gas can be applied to SI(spark ignition) engines due to its anti-knocking and low auto-ignitibility characteristics. Recently, since turbocharged SI engine has been widely used, it needs to apply natural gas on the turbocharged SI engine. However, there is a major challenge for using natural gas on turbocharged SI engine, because it is hard to make natural gas direct injection in the cylinder, while gasoline is possible. As a result, there is a loss of fresh air when natural gas is injected by MPI (multi-point injection) method under the same intake pressure with gasoline-fueled condition. It brings the power reduction. Therefore, in this research, intake pressure was increased by controling the turbocharger system under natural gas-fueled condition to improve power output. The goal of improved power is the same level with that of gasoline-fueled condition under the maximum torque condition of each engine speed. As a result, the maximum power levels, which are the same with those of gasoline-fueled conditions, with improved brake thermal efficiency could be achieved for each engine speed (from 2,000 to 6,000 rpm) by increasing intake pressure 5-27 % compared to those of gasoline-fueled conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.351-358
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• 2006

The capability of high pressure injection with small fuel quantify at all engine operating conditions is one of the main feature in common rail fuel injection system, which is used in small and light-duty Diesel engine. The key parameter for the better atomized fuel sprays and multiple injections of this common rail fuel injection control, that can be freely selected irrespective of the engine speed and load is the mechanism controlling the needle energizing and movement in high pressure Diesel injector. In the electro-hydraulic injector, the injection nozzle is being opened and closed by movement of the injector's needle which is balanced by pressure between the nozzle seat and the needle control chamber. This study describes the macroscopic spray structure characteristics of the common rail Diesel injectors with different electric driving method i.e. the solenoid-driven and piezo-driven type. The macroscopic spray characteristics such as spray tip speed. spray tip penetration and spray cone angle were investigated by the high speed spray, which is measured by the back diffusion light illumination method with optical system for the high speed temporal photography in a constant volume chamber pressurized by nitrogen gas. As the results, the prototype piezo-driven injector system was designed and fabricated for the first time in domestic case and the effect of injector's needle response driven by different drive type was compared between the solenoid and piezo-driven injector It was found therefore. that the piezo-driven injector showed faster needle response and had better needle control capability by altering the electric input value than the solenoid-driven injector.