The gas flow and heat transfer inside an EGR cooler for a diesel engine are numerically analyzed to investigate the performance of EGR cooler. The commercial code FLUENT is utilized to simulate a single spiral tube with constant wall temperature condition. The numerical analysis is performed with the variation of exhaust gas flow rates according to engine speed. The computational results agree well with the experimental results published before. The results show that the maximum error rate is about 0.6% for all operating conditions. Thus a single tube model with constant wall temperature condition is appropriate for simulating EGR cooler.

The main objective of this work is to perform experimental analyses of a absorption refrigeration system using a new refrigerant-sorbent pair as the working pair. The active component of sorbent is sodium thiocyanate (NaSCN). Ammonia (NH3) is chosen as refrigerant. As a result of these, it is concluded that the unit exhibits good cooling performance and the average cooling capacity is approximately 28.8kW and the average coefficient of performance (COP) of absorption system is 0.56. The unit is a thermal compressor which uses low-grade waste heat to generate refrigeration (cooling or freezing).

The aims of research of this paper are as follows; first of all, main contents of technical development are such as. 1. the burner system development for maximum efficiency of diesel particulate filter in low temperature emission gas, 2. the development of white fume reducing system by the second ejection in diesel, 3. the development of burner system for erasing of oxidation catalyzer of the most important role in diesel particulate filter, And the secondhand, expectation effect of this paper is such as. If the mass production of this development is successfully, this system is easy to applicable to small diesel vehicle stopping by low efficiency diesel particulate filter and is increased cost effective and adaptability by erasing oxidation catalyzer.

The main contributors to the friction in modern internal combustion engines were identified at the top ring around the top dead center of the stroke. In this study, variations of the friction force between piston ring and cylinder liner were varied with piston speed, normal load and oil temperature as well as the properties of the ring materials were investigated experimentally. Their frictional behaviors when sliding against the steel cylinder bore materials lubricated with 10W-30 oil for a commercial medium speed diesel engine were investigated using a Pin-On-Disk tribotester. The results show that the hardness of ring has less effect on the friction force in comparison to the piston speed, normal load and oil temperature. And friction force is lower with harder metals.

LNGC 주기관의 크랭크 챔버 내 유증기 폭발 방지를 위해 기존의 이산화탄소 가스인젝터가 부착된 오일미스트 감지기 외에 불활성가스 시스템을 설치할 필요가 있다. 특히, LNGC 선박은 액체질소를 손쉽게 확보할 수 있는 장점이 있기 때문에 액체질소를 이용한 불활성가스 시스템을 도입하기 위한 설계 기초 단계로서 해석적 연구를 시행하였다. 또한 액체질소 최소 소모량 시스템을 개발하기 위하여 층상류 모델을 적용하였으며, 층상류 흐름에 미치는 유로관경, 포화압력과 선박동요에 따른 배관 기울기 등의 영향에 대해서도 조사하였다. 또한 질소와 같은 극저온 유체들과 여기에 사용된 예측 모델과의 비교 검토를 통하여 극저온 유체에 대해서도 모델의 유효성을 검증하였으며, 액체질소 불활성가스 시스템의 액체질소를 가스로 상변환 시키는데 소요되는 가열기의 열부하도 예측할 수 있었다.

In this study, the used DOCs, which could remove the air pollutants such as CO and HC in the exhaust gas from diesel vehicle, were remanufactured by various conditions. Their catalytic performances and characterization were also investigated. The remanufacturing process of the deactivated DOCs includes high temperature cleaning of incineration, ultrasonic cleaning for washing with acid/base solutions to remove deactivating materials deposited to the surface of the catalysts, and active component reimpregnation for reactivating catalytic activity of them. The catalytic performance tests of the remanufactured DOCs were carried out by the diesel engine dynamo systems and chassi dynamo systems in CVS-75 mode. All prepared catalysts were characterized by the optical microscopes, SEM, EDX, porosimeter and BET to investigate correlations between catalytic reactivity and surface characteristics of them. The remanufactured DOCs at various conditions showed the improved catalytic performances reaching to 90% of fresh DOC, which is attributed to remove the deactivating materials from the surface of the used DOC through the analysis of catalytic performance test and their characterization.

In order to test the applicability of bunker-A in a diesel engine for small-fishing boat, the investigation of the engine performance and the exhaust emission was performed under various conditions of fuel property, intake air pressure and fuel temperature. It was also performed based on IMO NOx Technical code. At high load, the energy consumption rate of bunker-A was lower than that of diesel oil, and the characteristics of exhaust emission of bunker-A were similar to those, and NOx emission rates of both fuels satisfied the IMO NOx emission regulation limits. The energy consumption rate and characteristics of exhaust emission were improved as the intake air pressure was increased, but these were not improved remarkably as the temperature of bunker-A was heated. However, at low load the energy consumption rate, CO emission rate and HC emission rate of bunker-A were higher than those of diesel oil, but NOx emission rates of the fuels were about the same. In addition, at low load the energy consumption rate and CO emission rate of bunker-A were increased as the intake air pressure and the temperature were higher than normal conditions. Accordingly, it is thought that the use of bunker-A in a kind of test engine is possible at high load. On the other hand, it is thought that more research is needed to improve the combustion efficiency under low temperature and low load condition.

The Effects of cooled and hot EGR(exhaust gas recirculation) on the characteristics of smoke and NOx emission have been investigated using a single cylinder, water-cooled, four cycle, DI diesel engine at several loads and speeds. In this study, a manually controlled EGR system was installed on a agricultural diesel engine which was operated at various operating system. And, the effects of hot EGR and cooled EGR on smoke and NOx emission were compared. The results showed that cooled EGR method was more effective than hot EGR method on smoke and NOx emission.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from diesel engine are recognized main cause which influenced environment strong. In this study, the potential possibility of biodiesel and oxygenates additives (dimethoxy methane) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel(biodiesel 90vol-% + DMM 10vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 70% at 2500rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emissions withg biodiesel and DMM blended fuel had been increased compared with commercial diesel fuel.

The goal of this study is to propose the effective method of investigating the injurious factors and making improved plans that prevents the workers against musculoskeletal disorders at an diesel engine manufacturing company and the same business field with similar working conditions and process. A questionnaire were adopted to analyze the symptoms of workers' musculoskeletal disorders, and an ergonomic assessment method such as RULA, OWAS were performed to find out harmful factors of workplace and working posture. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. It can be concluded that the method and process described in this paper could be helpful for diagnosing the musculoskeletal disorders and making improvement plans to the diesel engine fuel injection system manufacturing company and the same business field with similar working conditions and process.

In this study, the potential possibility of oxygenates on butyl ether(below BE) was investigated as an combustion activator for a direct injection diesel engine. It tested to estimate change of engine performance and exhaust emission characteristics for the diesel fuel and oxygenates additives blended fuel which has four kinds of blended ratio. The smoke of blended fuel(diesel fuel 80vol-%+BE 20vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 26%. And, power, torque and brake specific fuel consumption(BSFC) didn't have no large differences. But, NOx of BE blended fuel was increased compared with diesel fuel.

There are increased in using the bio-ethanol, as the carbon neutral attracts many researchers due to a reduction in carbon dioxide spotted as the global warming gas. A gasoline engine with 100% of the bioethanol was developed and used in Brazil already, but researches of using the bio-ethanol in diesel engines are lack. In this study, combustion tests with blend fuel of the gas oil and bio ethanol by 50% maximally due to a low cetane number of bio-ethanol were accomplished as a basic study of introduction of using the bioethanol in diesel engines. The result was that smoke emission was decreased with increase in proportion of the bio-ethanol, due to the increase of a amount of pre-mixed combustion with ignition delay. Although the amount of CO2 is reduced according as the bio-ethanol is used(carbon neutral), the emission of CO2 with increase in the proportion of the bio-ethanol was more increased due to lower a heat value of bio-ethanol than gas oil.

In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for an indirect injection diesel engine. It was tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenate additive blended fuel which has four kinds of mixed ratio. Ethylene glycol mono butyl ether(EGBE) contains oxygen component 27% in itself, and it is a kind of effective oxygenated fuel of mono-ether group that the smoke emission of EGBE is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads in a IDI diesel engine.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engines are recognized as main causes of the air pollution. DI diesel engine is widely used for the sake of minimization on exhaust emission. Because biodiesel fuel is a renewable and alternative fuel for diesel engine, its usability is expanded. The smoke emission of esterfied rapeseed oil is reduced remarkably in comparison with commercial gas oil, that is, it was reduced approximately 44.5% at 1500rpm. But, brake specific energy consumption showed very slight differences. It was concluded that esterfied rapeseed oil can utilize effectively as an alternative and renew-able fuel for diesel engine.

The potential possibility of oxygenated fuel for di-ether group oxygenated additives such as Methyl tertiary butyl ether(MTBE) and diethylene glycol dimethyl ether(DGM) were investigated for the sake of exhausted smoke reduction from diesel engine. They include oxygen content approximately from 18% to 36%, it is a kind of oxygenated fuel that the smoke emission of them is reduced remarkably compared with commercial diesel fuel. In the experiment by gas chromatography, unburned hydrocarbons of oxygenated fuel were reduced than those of commercial diesel fuel.

산유국으로부터 에너지 독립을 하고 대기오염방지를 위한 배기배출물을 저감시키기 위하여 대체연료에 많은 관심을 가지고 있다. 폐유나 새로운 식물성 기름과 동물성 기름으로부터 생성할 수 있는 바이오디젤유가 압축점화기관인 디젤기관에 구조적인 변화없이 사용될 수 있다. 이 논문에서는 4행정 직접분사식 디젤기관을 이용하여 순수 디젤유와 바이오디젤 혼합유(바이오디젤 10% 및 20% 함유)의 연료소비율과 배기배출물에 미치는 영향을 제시했으며, 특히 실험에 사용된 바이오디젤 연료는 우리 실험실에서 유채유로부터 직접 생산되었다. 이 연구 결과 바이오디젤 혼합유가 디젤유 보다 연료소비율과 질소산화물은 약간 증가 되었고 일산화탄소와 매연은 상당히 감소되었다.