• 한국정밀공학회지
• /
• 제26권12호
• /
• pp.85-93
• /
• 2009

This research is intended to grasp the characteristics of heat flow inside auxiliary power device engine room to obtain the design basic data through numerical analysis and experiment. For experiment cost reduction, numerical analysis was done to obtain quantitative data by observing the change in temperature distribution of major parts according to changes in normal condition, incompressible condition, engine surface heat emission rate and absorption temperature with the use of commercial STAR-CD. The experiment was done by grasping the temperature distribution of major interested parts inside engine room in loaded and unloaded conditions during engine operation. The temperature distribution data here will serve as useful design data during APU engine room designing.

• 한국추진공학회지
• /
• 제24권6호
• /
• pp.93-100
• /
• 2020

액체로켓엔진의 터보펌프는 추진제 상태 변화로 인한 캐비테이션 발생을 최소화하기 위해 인듀서를 사용한다. 그러나 인듀서에서 발생하는 캐비테이션 불안정성은 엔진 개발의 큰 문제점으로 알려져 있다. 본 논문에서는 한국형발사체 1단용 엔진이 낮은 입구압력 조건에서 작동될 때 캐비테이션 불안성에 의한 엔진 작동 특성을 검토하고 엔진의 신뢰도를 확인하고자 하였다. 산화제펌프의 캐비테이션 불안정성을 대표하는 특성주파수가 산화제펌프와 연료펌프를 비롯한 엔진 여러 곳에 부착된 동압센서, 가속도계, 스트레인 게이지 등의 신호에서 뚜렷하게 관찰되었다.

• 한국자동차공학회논문집
• /
• 제1권2호
• /
• pp.1-16
• /
• 1993

It is widely recognized that exhaust emissions, fuel economy and engine torque are affected by engine temperature, and logic would suggest that a cooling system offering a better compromise of engine temperature would improve both overall engine performance and economy. Author measured coolant temperature of some parts and flow rate which are necessary to heat transfer in a engine. And Author determined parameters necessary for the optimum design of a thermostat to keep the best engine performance ; determined the optimum operating temperature of electric cooling fan. A summary of this study is followed. 1. Study of the effects of cooling condition to combustion character in a engine. 2. Analyze of heat transfer surrounding engine cylinders. 3. Study of the effects of cooling character to engine heat rejection, determination of the optimum collant temperature for keeping the optimum engine performance and determination of the optimum design of a thermostat for keeping that temperature.

• Tribology and Lubricants
• /
• 제13권2호
• /
• pp.8-15
• /
• 1997

It is very difficult to express the state of a tested engine objectively concerning the malfunction, failure and wear of an engine. The general method of engine evaluation is to express evaluator's opinion for the engine state after testing. However, these methods is only subjective evaluation because test engineers, designers, and evaluators does not easily coincide in opinion. Therefore, in this article, the method of engine rating are introduced in order to represent the qualitative trends into quantitative value. The purpose of Engine Rating is to assign a quantified value to the tribology state of a tested engines. Originally, this Engine Rating method have been used to evaluate the performance of engine oil quantitavely. Using this method, we can predict the proper interval of engine oil change due to its objectivity. So, we can prevent the frequent change of engine oil and protect the environmental contamination. Furthermore, this method can be used to tell the general state of a tested engine after finishing engine durability tests. A single merit scale is used to evaluate numerically the state of cleanliness and the mechanical condition. Generally, a part which is absolutely clean or shows no wear, is rated merit 10. A part which is absolutely dirty or very worn, is rated merit 0.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
• /
• pp.333-334
• /
• 2006

Extinguishing a fire at an early stage is most important to prevent spreading of a fire in Unmanned Engine Room. The most proper fire extinguish system was analyzed after examining the Automatic spread Extinguish System, which is mostly installed in Unmanned Engine Room, reproduced in the condition of real Unmanned Engine Room.

• 한국자동차공학회논문집
• /
• 제8권3호
• /
• pp.12-17
• /
• 2000

In this study a heavy duty diesel engine was modified into a 11-liter 6-cylinder SPI CNG dedicated engine, which was tested to investigate the performance and exhaust emission under the maximum load condition as the engine speed was increased in the range of 1,000∼2,200 rpm. The exhaust emission was also measured at D-13 mode as well as AVL-8 mode.

• 한국공작기계학회논문집
• /
• 제10권4호
• /
• pp.65-69
• /
• 2001

Research on the development of CNG dedicated engine that has important meaning both as a clean fuel and an alterna- tive energy to reduce the exhaust emission from diesel engine are actively going on these days. In this study, in order to present the direction and application of CNG engine, we tested the CNG engine performance experimented by changing the parameters such as ignition timing, equivalent ratio. The engine performance experimented by changing the parameters such as ignition timing, equivalent ratio. The engine performance and exhaust emission were measured by engine performance model at maximum load condition with increasing the rpm in the range of 1,000∼2,200rpm. Also, the testing engine was heavy-duty CNG dedicated engine with displacement of 11,050cc.

• 한국산업융합학회 논문집
• /
• 제23권4_2호
• /
• pp.645-651
• /
• 2020

In this study, It is necessary that we should study on more effective use about reciprocating engines because there are huge increase of air pollution. Diesel Engine is operated by injecting fuel directly to combustion chamber with high pressure. Diesel Engine has greater thermal efficiency and durability than Gasoline Engine. Also, Diesel Engine emitted low harmful exhaust witch caused by Gasoline Engine. There are many ways to improve of performance and decrease of harmful exhaust by controlling injection timing, changing amount of fuel and engine speed and so on. Especially, development and application of common rail direct injection Engine cause the increase of thermal efficiency by controlling a various of operating conditions. In this study we analyze characteristics of performance by changing a various of operating conditions.

• 한국자동차공학회논문집
• /
• 제19권2호
• /
• pp.26-34
• /
• 2011

Hybrid powertrain systems have been developed to improve the fuel efficiency of internal combustion engines. In the case of a parallel hybrid powertrain system, an engine and a motor are directly coupled. Because of the hardware configuration of the parallel hybrid system, friction and the pumping losses of internal combustion engines always exists. Such losses are the primary factors that result in the deterioration of fuel efficiency in the parallel-type hybrid powertrain system. In particular, the engine operates as a power consumption device during the fuel-cut condition. In order to improve the fuel efficiency for the parallel-type hybrid system, cylinder deactivation (CDA) technology was developed. Cylinder deactivation technology can improve fuel efficiency by reducing pumping losses during the fuel-cut driving condition. In a CDA engine, there are two operating modes: a CDA mode and an SI mode according to the vehicle operating condition. However, during the mode change from CDA to SI, a serious fluctuation of the air-fuel ratio can occur without adequate control. In this study, an air-fuel ratio control algorithm during the mode transition from CDA to SI was proposed. The control algorithm was developed based on the mean value CDA engine model. Finally, the performance of the control algorithm was validated by various engine experiments.

• 한국추진공학회지
• /
• 제14권2호
• /
• pp.10-18
• /
• 2010

스크램제트 엔진은 현재 차세대 추진기관의 핵심구성품으로 주목받고 있으며, 현재 미국, 프랑스, 일본, 중국, 인도 등 전세계적으로 활발한 연구가 진행되고 있다. 항공우주연구원은 2007년 모델스크램제트 엔진 S1의 지상시험에 이어, 성능을 개선한 S2모델의 지상시험을 2009년 4월 수행하였다. 엔진시험모델은 설계마하수 6.7의 조건으로 제작되어 Off-design condition인 마하 7.7의 조건에서 지상시험이 수행되었다. 시험결과에서 본 시험모델은 흡입구 카울 안쪽의 충격파 중첩으로 인하여 유동의 박리현상이 발생하였으며, 이로 인하여 엔진 내부의 압력진동이 관찰되었다. 그러나, 연소기 내부에서 초음속 연소는 안정적으로 발생하였으며, 엔진의 격리부는 엔진 내 압력섭동이 흡입구로 전파되는 것을 차단하여 엔진불시동을 방지하는 것으로 나타났다. 또한 항우연의 S2 모델은 다른 시험모델과의 성능비교에서 추력 및 비추력 성능이 우수한 것으로 나타났다.