• 한국분무공학회지
• /
• 제2권2호
• /
• pp.43-50
• /
• 1997

The purpose of this investigation is to carry out, the influence factor on the fuel spray characteristics for improve the engine combustion performance and exhaust omission in direct injection type diesel engine. The fuel properties, fuel spray structure and the shape or the piston surface of diesel engine play an important role of engine combustion process and exhaust emission. In order to obtain the effect of using auxiliary chamber and emulsified fuel on the fuel spray characteristics the experiment un conduct with single cylinder direct injection type diesel engine to examine the engine performance and gas emission. The results of this investigation showed that the increase auxiliary chamber volume and emulsified fuel give an effect on the fuel spray characteristics by reduced the concentration of nitric oxide emission in the combustion chamber. Also it can improve the combustion characteristics such as cylinder pressure, rate of pressure rise and rate of heat release.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권9호
• /
• pp.1081-1086
• /
• 2014

본 연구는 4실린더 커먼레일 디젤기관에서 식물성 바이오 연료인 카롤라유(Canola oil)와 디젤연료를 혼합하여 사용하였을 때 바이오디젤 혼합율과 엔진 회전수 변화에 따른 연소 및 배기 배출물 특성을 조사하기 위하여 실험을 수행하였다. 실험 결과에 의하면 엔진 회전수 1,000, 1,500, 2,000(rpm)에서 연소 압력은 바이오디젤 혼합율이 증가할수록 감소하고, 2500rpm에서는 바이오디젤 혼합율이 증가할수록 증가 하였으며, 열 발생율은 바이오디젤 혼합율이 증가 할수록 모두 증가하였다. 연료 소비율은 바이오디젤 혼합율이 증가할수록 엔진 회전수가 상승할수록 증가하였다. CO 배출물은 엔진 회전수가 상승할수록, 바이오디젤 혼합율이 증가할수록 감소하였다. $CO_2$, NOx, 배출물은 엔진 회전수가 상승할수록 바이오디젤 혼합율이 증가할수록 증가하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2007년도 추계학술대회 논문집
• /
• pp.431-432
• /
• 2007

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2009년도 추계학술대회 논문집
• /
• pp.84-88
• /
• 2009

The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. The exhaust valves of low speed diesel engines are usually operated at temperature levels of 400-$600^{\circ}C$ and high pressure to enhance thermal efficiency and exposed to the corrosion atmosphere by the exhaust gas. Also, the exhaust valve is subjected to repeated thermal and mechanical loads. So, the nickel-based alloy Nimonic 80A was used for the large exhaust valve spindle. It is composed a 540mm diameter head and a 125mm diameter stem. It is developed large products by hot closed-die forging. Manufacturing process analysis of the large exhaust valve spindle was simulated by closed die forging with hydraulic press and cooled in air after forging. The preform was heated to $1080^{\circ}C$ Numerical calculation was performed by DEFORM-2D, a commercial finite element code. Heat transfer can be coupled with the deformation analysis in a non-isothermal deformation analysis. Mechanical properties of the large exhaust valve spindle were evaluated by the variety of tests, including microstructure observation, tensile, as well as hardness and fatigue tests, were conducted to evaluate the mechanical properties for head part of exhaust valve spindle.

• 한국정밀공학회지
• /
• 제24권6호
• /
• pp.86-95
• /
• 2007

This paper presents the optimal design of an exhaust system of a vacuum-compatible air bearing using a genetic algorithm. To use the air bearings in vacuum conditions, the differential exhaust method is adopted to minimize the air leakage, which prevents air from leaking into a vacuum chamber by recovering air through several successive seal stages in advance. Therefore, the design of the differential exhaust system is very important because several design parameters such as the number of seals, diameter and length of an exhaust tube, pumping speed and ultimate pressure of a vacuum pump, seal length and gap(bearing clearance) influence on the air leakage, that is, chamber's degree of vacuum. In this paper, we used a genetic algorithm to optimize the design parameters of the exhaust system of a vacuum-compatible air bearing under the several constraint conditions. The results indicate that chamber's degree of vacuum after optimization improved dramatically compared to the initial design, and that the distribution of the spatial design parameters, such as exhaust tube diameter and seal length, was well achieved, and that technical limit of the pumping speed was well determined.

• 오토저널
• /
• 제7권2호
• /
• pp.45-54
• /
• 1985

Recently, the problem of exhaust gas pollution is increasingly being aggravated by the active use of the Diesel engine. For the fuel-injection system which affects the composition of exhaust gas from the Bosch type single-hole nozzle in the Diesel engine, a mathematical model was set up to study pressure variations in the high pressure pipe, the injection rate, and the needle lift. The fundamental equations of the mathematical model have been solved by the Newton Raphson Method applying the Finite Diffrence Method. The effective stroke of the injection pump plunger due to a change in engine rpm was calculated by the measurement of Control Rack, Pinion, and Plunger sizes and by the use of Characteristic Curve of Governor. The computed results for the pressure variations in the high pressure pipe and needle lift at 800 rpm and 1000 rpm are in good agreement with experimental ones in general. By a developed program, the effects of other various parameters will by calculated for the performance of the fuel-injection system.

• 한국공작기계학회논문집
• /
• 제15권1호
• /
• pp.76-81
• /
• 2006

Modem after-treatment technology has been developed variously in order to decrease exhausted emission in diesel engine. However, it seems very difficult to comply with updated stringent emission standards. Specially, it has been many years that exhaust gas from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx and PM among those compositions. Thus, this research focused on the electronic control EGR and the target for this research is heavy-duty turbo-diesel engine with EGR technology(High pressure route and low pressure route system).

• 소음진동
• /
• 제9권1호
• /
• pp.113-120
• /
• 1999

A perforated tube nozzle as an exhaust noise suppressor of a high-speed civil transport(HSCT) is proposed. The experimental results for the near and far field sound. the visualization of jet structures and the static pressure distributions in the jet passing through a perforated tube are presented and discussed in comparison with those for a simple tube. It is shown that the perforated tube has an excellent performance to greatly reduce the shock-associated noise and that also the turbulent mixing noise is reduced in the range of a limited jet pressure ratio. This considerable noise reduction is due to the pressure relief caused by the through-flow through the perforated holes. Such a pressure relief results in the transformation of normal shock waves into weak Mach waves of X -type and increases the thrust force of the perforated tube nozzle.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.667-669
• /
• 2014

Development of 3 cylinder turbo charger engine is increasing due to engine down-sizing, cost reduction and emission regulations. However, 3 cylinder engine makes higher Exhaust manifold gas pressure(P3) pulsation than 4 cylinder engine and it generate boosting air with high pulsation. The mechanical waste-gate turbocharger just controlled by the boosting air has higher movement because of this high pulsation boosting air. This causes high vibrations to wasted gate and accelerate wear of the linkage system. So we need to understand out of the exhaust gas pressure pulsation changed by turbocharger compressor pressure(P2) Pulsation. In this study, we discuss how to prevent to abnormal movement of the turbo actuator by stabilized P2 Pulsation.

• 한국안전학회지
• /
• 제13권3호
• /
• pp.32-44
• /
• 1998

Analysis on the study for the sodium fire mitigation was carried out using the CONTAIN-LMR code. Sodium loop building was partitioned into the many cells, in which the safety venting systems were installed for the purpose of improving the sodium fire safety and minimizing its effect on the sodium loop building. The effects of sodium fire on sodium loop building partitioned into the many cells and not partitioned were investigated. The peak pressure and temperature of each cell accompanied by sodium fire in sodium loop building partitioned were lower than those of sodium loop building not partitioned. In the case of partitioning sodium loop building, the pressures, temperatures and aerosols into cells were transferred through propagation path of CONTAIN-LMR sodium fire model simulated by this study, and the effect of sodium spray fire on sodium loop building was mitigated by partitioning building. In addition, the excessive rise of pressure into cells was prevented by installing the over-pressure exhaust valve and under-pressure exhaust valve on the flow path between cells.