• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1436-1448
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• 2006

This paper describes the effects of injection rate shaping on the combustion, fuel consumption and emission of $NO_x$ and soot of a medium duty diesel engine. The focus is on the influence of four different injection rate shapes, square type 1, square type 2, boot and ramp, with a variation of maximum injection pressure and start of injection (SOI). The experiments were carried out on a 1 liter single cylinder research diesel engine equipped with an amplifier-piston common rail injection system, allowing the adjustment of the injection pressure during the injection event and thus injection rate as desired. Two strategies to maintain the injected fuel mass constant were followed. One where rate shaping is applied at constant injection duration with different peak injection pressure and one strategy where rate shaping is applied at a constant peak injection pressure, but with variable injection duration. Injection rate shaping was found to have a large effect on the premixed and diffusion combustion, a significant influence on $NO_x$ emissions and depending on the followed strategy, moderate or no influence on soot emission. Only small effects on indicated fuel consumption were found.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.305-314
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• 2005

Injection rate shape control is one feature of a diesel fuel injection system that is strongly desired at this time. In the conventional common rail system, it is difficult to control the injection rate since the fuel pressure is constant during the injection period, resulting in a nearly rectangular rate shape. In order to look into possible injection modulations, injectors equipped with standard and geometrically modified control valves were investigated in detail by means of computer modelling and simulation. Experiments were carried out to validate the feasibility of such a shaping. The results of this study show a noteworthy dependence of the fuel rate on geometrical modifications in the piloting stage of the injector.

• 산업경영시스템학회지
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• 제22권52호
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• pp.9-20
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• 1999

The standard deviation is constant in the progress of Powder Injection Filling, The setting value of the filling amount can modify the numerical rate. Since high level of the numerical rate can get the effect of reducing the material cost, it improves the productivity by permitting the possibility of the economical production. Consequently, this thesis analyzed and suggests the numerical model which consider the economical factors of the Powder Injection Shaping progress, and I try to reinforce the competitive powder of the domestic medicine manufacture industry which face the wave of globalism and evolutionism.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.107-114
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• 2017

터보차저는 배기가스로 구동되는 엔진 과급기를 말하며, 배기에너지를 이용하여 배기통로에 연결된 터빈의 회전력을 변화시켜, 혼합 가스의 충전효율을 높여 출력과 연비를 향상 시키는 부품이다. 이러한 목적에 따라 과급을 조절해주는 것이 중요하며, 핵심 부품 중 노즐 슬라이드 조인트가 있다. 소재는 현재 오스테나이트 계 스테인리스강으로 높은 내열성과 내식성 등의 우수한 기계적 성질을 이용하고 있다. 그러나 절삭성이 나쁘기 때문에 절삭가공에 의해 복잡한 형상의 제품을 만드는데 어려운 점이 많다. 현재 노즐 슬라이드 조인트의 가공방법은 금속분말 사출성형후 치수정밀도를 위해 절삭가공을 행하고 있다. 따라서 본 연구에서는 Nitronic 60을 이용하여 터보차저 과급유량을 조절해주는 노즐 슬라이드 조인트의 제작 공정에서 절삭가공이 필요 없는 정형가공 공정을 제안하기 위하여, 기계적 특징에 영향과 연관이 있는 소결온도, 제품의 응력 및 변형률, 형상과 관련이 있는 모따기 펀치각도 및 펀치의 곡률반경을 설계변수로 선정하였다. 그에 따라 유한요소해석과 실험계획법인 다구찌법 및 SN비를 이용하여 가장 좋은 공정 조건을 제안하였다. 최종제품과 유한요소해석 결과의 상대밀도 및 정수압을 비교하여 경향이 일치함을 알 수 있었다. 따라서 다구찌법을 이용한 금속분말의 성형공정 설계에 유용하게 적용할 수 있을 것으로 판단된다.