• 한국분무공학회지
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• 제20권3호
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• pp.195-201
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• 2015

This study discusses a fuel injector test bench containing a mechanical type fuel supply system for heavy duty diesel engine. The main focus of this study was to evaluate the design stability of the test bench, which basically measures the injector durability of a multi-hole heavy duty injector by using pure diesel as a test fuel. In this experiment, diesel spray was controlled by a specially designed control box and all the experiments were carried out to measure e.g. fuel injection pressure and fuel injection quantity to understand the injection status which is interlinked with the stability factor of total test bench design. Also, the durability test was performed to understand the heavy duty operation lastingness of the designed system and the flow rate of the installed distributor pump in the fuel supply system of this studying test bench was compared with LO-1 and LO-2 pump. The results of the above mention tests revealed that the injector test bench design and control system can serve the purpose for heavy duty injector.

• 한국가스학회지
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• 제13권1호
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• pp.28-33
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• 2009

천연가스는 전세계적으로 매장량이 풍부하며 청정성과 경제성을 동시에 갖춘 연료로써 향후 자동차용 연료로 널리 사용될 전망이다. 천연가스를 사용하는 엔진의 출력 및 배출가스 특성을 최적화하기 위해서는 연료량 제어가 필수적이며 이를 위해서는 분사기의 성능이 매우 중요하다. 본 연구에서는 대형 가스엔진에 고유량을 공급할 수 있는 가스분사기를 직접 개발하여 실제 엔진에 장착하여 기존의 고유량 가스분사기와 성능을 비교하였다. 본 연구에서 개발한 가스분사기는 듀티 증가에 따라 선형적인 유량 특성을 지니고 있음을 파악하였으며 이를 통해 분사량 제어성이 우수하다는 것을 확인하였다. 또한 듀티 10% 미만의 조건에서도 분사유량은 선형성을 지니고 있으며 제어성도 우수하다.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.68-78
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• 2006

In the past few years, considerable efforts have been directed towards the further development of Urea-SCR(selective catalytic reduction) technique for diesel-driven vehicle. Although urea possesses considerable advantages over Ammonia$(NH_3)$ in terms of toxicity and handling, its necessary decomposition into Ammonia and carbon dioxide complicates the DeNOx process. Moreover, a mobile SCR system has only a short distance between engine exhaust and the catalyst entrance. Hence, this leads to not enough residence times of urea, and therefore evaporation and thermolysis cannot be completed at the catalyst entrance. This may cause high secondary emissions of Ammonia and isocyanic acid from the reducing agent and also leads to the fact that a considerable section of the catalyst may be misused for the purely thermal steps of water evaporation and thermolysis of urea. Hence the key factor to implementation of SCR technology on automobile is fast thermolysis, good mixing of Ammonia and gas, and reducing Ammonia slip. In this context, this study performs three-dimensional numerical simulation of urea injection of heavy-duty diesel engine under various injection pressure, injector locations and number of injector hole. This study employs Eulerian-Lagrangian approach to consider break-up, evaporation and heat and mass-transfer between droplet and exhaust gas with considering thermolysis and the turbulence dispersion effect of droplet. The SCR-monolith brick has been treated as porous medium. The effect of location and number of hole of urea injector on the uniformity of Ammonia concentration distribution and the amount of water at the entrance of SCR-monolith has been examined in detail under various injection pressures. The present results show useful guidelines for the optimum design of urea injector for reducing Ammonia slip and improving DeNOx performance.

• 한국가스학회지
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• 제20권4호
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• pp.1-6
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• 2016

버스와 같은 대형 차량에서 사용되는 대형 CNG 엔진에는 가스 연료 분사를 위한 인젝터가 6개 가량의 단위로 모듈 형태를 구성하고 있다. 이러한 인젝터 모듈은 연료 공급을 위한 입출구가 각각 한 곳으로 구성되어 있으며 쓰로틀 후단을 통하여 흡기관으로 연료를 공급하는 방식이므로 과도 운전에 대한 응답성이 매우 낮은 구조를 형성하고 있다. 본 연구에서는 이러한 인젝터 모듈의 내부 유로에 대한 유동 해석을 통하여 응답성을 개선할 수 있는 방안을 제시하고자 한다. 결론에 따르면 내부 유로의 체적을 감소시킴으로써 가스 연료의 공급 응답성을 개선할 수 있었고, 각각의 인젝터에서 모듈의 출구까지의 거리를 동일하게 하는 방안도 응답성과 연료 공급량의 선형성을 확보할 수 있는 것을 확인하였다. 다만 각 인젝터의 분사 순서 시기에는 큰 영향을 받지 않는 결과를 보였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.892-895
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• 2017

대형 가스터빈 연소기 구성품인 단일 압력선회식 연료분사기(Pressure swirl simplex liquid injector)를 설계, 분무특성 및 성능을 시험을 통해 평가하였다. 공급 압력 대비 분무 유량을 측정하여 설계점 기준 분무유량과 비교하였으며 섀도우그래프(Shadowgraph)를 통해 분무가시화이미지를 기록, 분무의 형상을 정성적으로 파악하고 분무각을 측정하였다. 시험 결과 동일한 공급압력 대비 측정된 분무유량은 설계점 기준 유량과 거의 일치하여 설계 및 제작의 정합성이 확인되었으며 섀도우그래프 이미지를 통해 연료분사기의 분무형상을 파악하고 설계 의도된 분무각이 나타남을 확인할 수 있었다. 이를 기반으로 향후 PDA(Phase Doppler Anemometry)를 통한 분무측정을 통해 보다 구체적인 연료 분사기의 분무 성능 및 특성을 파악할 수 있을 것으로 기대된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.896-902
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• 2001

To meet strict emission regulation while improving engine performances, common rail injection system which is suitable for electronic control, and capable of controlling injection quantity, timing, rate and pressure individually as well as realizing high pressure has been developed. At present study, a 8L DI diesel engine was converted to a single-cylinder experimental engine allowing optical access through an extended piston and a prototype of common rail injector in progress was applied to the engine. The combustion characteristics of the engine were analysed by using direct images and characteristics of the injector were analysed. We can not say that the results are always the same to general common rail injection system but that they are just characteristics of specific prototype injector.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.101-107
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• 2005

In this paper, optimized operating parameters were found using multi-dimensional engine simulation software (KIVA-3V) and micro-genetic algorithm for heavy duty diesel engine. The engine operating condition considered was at 1,737 rev/min and 57 % load. Engine simulation model was validated using an engine equipped with a high pressure electronic unit injector (HEUI) system. Three important parameters were used for the optimization - boost pressure, EGR rate and start of injection timing. Numerical optimization identified HCCI-like combustion characteristics showing significant improvements for the soot and $NO_X$ emissions. The optimized soot and $NO_X$ emissions were reduced to 0.005 g/kW-hr and 1.33 g/kW-hr, respectively. Moreover, the optimum results met EPA 2007 mandates at the operating point considered.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.16-23
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• 2011

Low temperature combustion is one of the advanced combustion technology in an internal combustion engine to reduce soot and nitrogen oxides simultaneously. In present experiment three kinds of injector were used to investigate the influence of injection angle and number of nozzle holes on the low temperature combustion in a heavy duty diesel engine. Low temperature diesel combustion is realized from the exhaust gas recirculation rate of 60%. Indicated mean effective pressure of low temperature combustion corresponds to the 70% level of conventional diesel engine combustion. Reduction of hydrocarbon and carbon monoxide, which are produced in low temperature combustion because of the low combustion temperature and a deficit of oxygen, was achieved by using various injector configuration. The result of experiment with $100^{\circ}$ injection angle and 8 holes showed that reductions in hydrocarbon and carbon monoxide could be achieved 58% and 27% respectively maintaining the 7% increased indicated mean effective pressure in low temperature diesel combustion compared with conventional injector.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.165-172
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• 2008

Urea-SCR, the selective catalytic reduction using urea as reducing agent, has been investigated for about 10 years in detail and today is a well established technique for deNOx of stationary diesel engines. In the case of the SCR-catalyst a non-uniform velocity and $NH_3$ profile will cause an inhomogeneous conversion of the reducing agent $NH_3$, resulting in a local breakthrough of $NH_3$ or increasing NOx emissions. Therefore, this work investigates the effect of flow and $NH_3$ non-uniformities on the deNOx performance and $NH_3$ slip in a Urea-SCR exhaust system. From the results of this study, it is found that flow and $NH_3$ distribution within SCR monolith is strongly related with deNOx performance of SCR catalyst. It is also found that multi-hole injector shows better $NH_3$ uniformity at the face of SCR monolith face than one hole injector.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.78-85
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• 2000

This study is to develop the diesel engine which has 6 cylinder natural aspiration direct injection type of 7.4$\ell$ with high performance, low emissions and low fuel consumption Finally the developed engine meets Korean `98 exhaust emission regulation for the city bus of heavy duty diesel engine by optimizing the various combustion parameters affecting performance and exhaust emissions. Combustion parameters are the swirl ratio of intake ports, the profile of injection pump`s cam affecting injection pressure, the design features of piston bowl of injection pump`s cam affecting injection pressure, the design features of piston bowl of combustion chamber and injector`s hole size. Through experimental analysis, various combustion parameters are optimized and the results are as follows; the swirl ratio is 2.20, the profile of injection pump`s cam is concave and re-entrant ratio, inner diameter of piston bowl and hole diameter of injector is 0.88,$\psi$64.0mm and $\psi$0.25mm respectively.