Gas turbine engines are widely used as prime movers of generator and propulsion system in warships. This study addresses the problem of designing a DS-based PID controller for speed control of the LM-2500 gas turbine engine used for propulsion in warships. To this end, we first derive a dynamic model of the LM-2500 using actual sea trail data. Next, the PRC (process reaction curve) method is used to approximate the first-order plus time delay (FOPTD) model, and the DS-based PID controller design technique is proposed according to approximation of the time delay term. The proposed controller conducts set-point tracking simulation using MATLAB (2016b), and evaluates and compares the performance index with the existing control methods. As a result of simulation at each operating point, the proposed controller showed the smallest in , which means that the rpm does not change rapidly. In addition, IAE and IAC were also the smallest, showing the best result in error performance and controller effort.

In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

최근 지구의 기후변화는 온실가스가 원인으로 전 세계적 대기환경문제로 크게 부각되고 있다. 국내에서도 기후변화에 적극 대응하기 위한 기술개발이 꾸준히 진행되고 있다. 날씨의 이상고온으로 인한 환경에 미치는 영향과 갑작스런 집중호우가 환경에 미치는 영향을 대상으로 하였다. 우리생활 주변 대기온도가 상승하였을 때 온도변화에 의한 대기오염발생에 미치는 영향을 연구하고자 한다. 본 연구의 실험조건은 선박 디젤기관에서 회전수 1400 rpm, 1600 rpm 그리고 1800 rpm, 부하는 0 %에서 25 %씩 100 %까지 하였고, 흡기 온도변화 는 20℃에서 50℃까지 구분하여 연구하였다. 연구한 결과 흡기온도가 증가함에 따라 일산화탄소 및 탄화수소는 약간 감소하였으나 연료 소비율, 질소산화물, PM은 약간 증가하였다. 또한 연소온도는 큰 변화가 없었다.

In this paper, the influence of the injector failure of the GDI engine on the air-fuel ratio inside the combustion chamber can be analyzed through time and shape analysis of the damping process of the ignition coil secondary waveform at 800rpm, 1500rpm, 2000rpm, 3000rpm. In particular, there is a correlation that affects air pollution associated with global warming, such as HC and NOx. To prevent this, periodic injector inspections can improve the fuel efficiency of the vehicle and reduce exhaust pollutants.

Emissions of hazardous substances in automobiles are caused by combustion of internal combustion engines, friction of brake pads and tire wear. In this study, we propose a method to reduce the harmful substances emitted in internal combustion engine by using HHO gas. In order to reduce the exhaust gas of the internal combustion engine, HHO gas having excellent combustion characteristics was added to the combustion chamber. The HHO gas generator was installed in the intake line and the HHO gas was introduced into the combustion chamber with the mixed gas through the intake line. At this time, we compared and analyzed the performance of the engine performance on the presence and absence of HHO gas.

About 30 percents of the energy produced by a gasoline engine is used to move a car, and nearly 70 percent is lost through waste heat. A thermoelectric generator module can harvest some of this waste heat. Thermoelectric power generation voltage and current according to the temperature change at high temperature part of thermoelectric module is increased. The reason is that the Bi-Te based thermoelectric module which is to recover waste heat of exhaust gas is increased according to high temperature. The maximum power of 5.1 Watt at 230℃ was generated at energy harvesting system using exhaust gas from internal combustion engine. Thermal power module temperature difference between both ends of the high temperature and low temperature section increases the maximum output power increases. The key factor of Thermoelectric power generation performance is the temperature difference between the both ends

Hydrogen has the very high heating value by comparing with other fuels and its combustion exhausts no carbon. But hydrogen causes the very high adiabatic flame temperature which generates thermal NOx. In this study, two cases of experiments were performed to compare engine characteristics. First and second cases are for only diesel combustion engine and mixed hydrogen diesel engine respectively. To verify the effect of mixed hydrogen-diesel combustion engine, the exhausted gas from modified dual fuel diesel engine was analyzed. In addition, diesel consumption per kWh for each case was estimated to validate its economic feasibility. By mixing hydrogen with 5kW brown(hydrogen-oxygen mixture) gas generator, the amount of CO(carbon mono-oxide) decreased from 330ppm to 210ppm by improving combustion and the amount of NOx increased from 390ppm to 520ppm by higher temperature of combustion chamber. Diesel consumption per kWh decreased from 450cc to 410cc but actually increased until 480cc because of the power of brown gas generator

The smoke emission of biodiesel fuel was reduced remarkably in comparison with diesel fuel, that is, it was reduced approximately 36% at 2000rpm, full load condition. And, power, torque and brake specific energy consumption showed no significant differences. However, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) to reduce the NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel(20vol-%) and cooled EGR method(10∼15%).

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 paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for a direct injection diesel engine. It was tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenated blended fuel which has seven kinds of mixed ratio. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission have been investigated. Ethylene glycol mono-n-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 and speeds in a diesel engine. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and cooled EGR method.

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.