• Journal of Advanced Marine Engineering and Technology
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• 제5권1호
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• pp.12-19
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• 1981

As the fuel oil cost covers from 45% to 60% of the total expenditure for fishing boat operation, the energy saving is now an urgent problem to be taken a countermeasure for engineers, manufacturers or specialists engaging in this field. Undertaking a second-hand engine of the trainging ship, the author made several reconstructions to restore its performances. By inserting foot linears of connecting rods the compression ratio was increased and by adjusting both the fuel injection timing and the cooling water outlet temperature, its thermal efficiency was improved. The results of the experimental operation were summarized as follows. 1. By raising the piston top position 0.75mm more than the value of the operating manual, the compression pressure increased 1.3 kg/$cm^2$ and the maximum pressure did 3.4 kg/$cm^2$ at 75% load. 2. At 75% load, the difference of the maximum pressure between each cylinder was decreased from 2.4 kg/$cm^2$ to 1.8 kg/$cm^2$. 3. The fuel consumption was decreased about 8 g/ps.h at 75% load, and about 5.3 g/ps.h at 85% load. 4. The brake thermal efficiency was improved about 1.5% at 75% load and 0.9% at 85% load.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 2부
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• pp.769-772
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• 2010

The objective of the current research work is to investigate the usage of biodiesel combined with the use of EGR in order to reduce the emission of all regulated pollutants from diesel engines. A single cylinder, air cooled, constant speed direct injection diesel engine was used for the experimental work and a cold EGR system was developed and fitted to the engine. Concentrations of HCs, NOx, and CO from the exhaust gas along with the smoke opacity were measured. Engine performance parameters such as the brake thermal efficiency (BTE) and the brake specific energy consumption (BSEC) were also calculated from the measured data. The results from the present investigation suggest that 25-30% EGR rate could give excellent NOx reduction without any significance penalty on smoke opacity or BSEC under the engine load of up to 40%. Under the full load condition, 15% EGR rate was found to be an option while higher EGR rate resulted in inferior performance and heavy smoke.

• Advances in Computational Design
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• 제4권4호
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• pp.367-379
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• 2019

Multiple Inputs and Multiple Outputs (MIMO) Fuzzy logic model is developed to predict the engine performance and emission characteristics of pongamia pinnata biodiesel with hydrogen injection. Engine performance and emission characteristics such as brake thermal efficiency (BTE), brake specific energy consumption (BSEC), hydrocarbon (HC), carbon monoxide (CO), carbon dioxide ($CO_2$) and nitrous oxides ($NO_X$) were considered. Experimental investigations were carried out by using four stroke single cylinder constant speed compression ignition engine with the rated power of 5.2 kW at variable load conditions. The performance and emission characteristics are measured using an Exhaust gas analyzer, smoke meter, piezoelectric pressure transducer and crank angle encoder for different fuel blends (Diesel, B10, B20 and B30) and engine load conditions. Fuzzy logic model uses triangular and trapezoidal membership function because of its higher predictive accuracy to predict the engine performance and emission characteristics. Computational results clearly demonstrate that, the proposed fuzzy model has produced fewer deviations and has exhibited higher predictive accuracy with acceptable determination correlation coefficients of 0.99136 to 1 with experimental values. The developed fuzzy logic model has produced good correlation between the fuzzy predicted and experimental values. So it is found to be useful for predicting the engine performance and emission characteristics with limited number of available data.

• 한국수소및신에너지학회논문집
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• 제23권4호
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• pp.373-381
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• 2012

To determine the performance characteristics of motorcycle engine using biogas for practical use, the intake system of a 110 cc motorcycle engine is properly modified to operate with biogas as a fuel. Biogas is a potentially renewable fuel for replacing gasoline in future, but it has high percentage of $CO_2$ that could lead to slow the burning rate of biogas-air mixture and cause instability in combustion. Thus, the performance characteristics of biogas-fueled motorcycle engines could be different from those of gasoline motorcycle engines. In this paper, the important parameters of performance characteristics (such as: power output, thermal efficiency, fuel consumption, exhaust emission,${\cdots}$) of biogas-fueled motorcycle engine are studied and estimated with change of engine speed and load. The obtained results when operating with biogas are used to compare with that of gasoline fuel under the same operating conditions. Engine speed in the experimental is changed from 1500 rpm (idle-mode) up to 3500 rpm by a step of 500 rpm. Engine load is changed from zero to maximum load with the help of an exciting voltage device from generator-type dynamometer. The experimental results show that the tested engine operated with richer biogas-air mixture than that of gasoline-air mixture under the same test conditions. Biogas-fueled engine gives a higher fuel consumption and lower thermal efficiency under the same power output. Brake thermal efficiency of biogas engine is found to be about 3% lower than gasoline-fueled motorcycle engine for whole range of speed. Exhaust emission of biogas-fueled motorcycle engine (such as: CO, HC) is found to be lower than the limitation level of the emission standards of Vietnam for motorcycle engines (CO <4.5% HC <1200 ppm).

• 한국가스학회지
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• 제22권6호
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• pp.34-39
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• 2018

최근 탈석유 에너지 이행의 목표가 분명해지는 가운데 천연가스가 가교연료로서 주목받고 있다. 천연가스는 옥탄가가 높아 압축비를 높여도 노킹이 일어나지 않기 때문에 열효율과 출력을 두루 향상시킬 수 있을 뿐 아니라 기존 내연기관 하드웨어 시스템에 천연가스 공급 시스템 적용을 비교적 용이하게 할 수 있다. 본 연구에서는 승용 가솔린 직분사 터보 엔진을 천연가스 포트분사식 터보 엔진으로 개조하여 터보가 작동되는 운전 영역에서 대상 엔진의 연소 및 성능을 종합적으로 측정 및 비교하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.551-558
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• 2004

Recently, fuel prices have been continually raised in diesel engine. Such a change in the fuel price influences enormously the development trend of marine diesel engines for slow speed, In other words, the focus was shifted from large diameter and high speed to low fuel consumption. Accordingly, more efforts are being made for engine manufacturing and development to develop highly efficient engines. In this study. a single cylinder 4 stroke cycle DI slow speed diesel engine was designed and manufactured, a 4 stroke cycle was configured and basic performances were evaluated. The results are as follows. The optimal fuel injection timing had the lowest value when specific fuel consumption was in BTDC 8~$10^{\circ}$, a little more delayed compared to high speed diesel engines. Cycle variation of engines showed about 5% difference at full loads. This is a significantly small value compared to the cycle variation in which stable operation is possible, showing the high stability of engine operation is good. The torque and brake thermal efficiency of engine increased with an increase of engine 250-450 rpm. but fuel consumption ratio increased from the 450 rpm zone and thermal efficiency abruptly decreased. Mechanical efficiency was maximally 70% at a 400 rpm that was lower than normal engines according to the increase of mechanical frictional loss for cross head part. The purpose of this study was to get more practical engines by comparing the above results with those of slow speed 2 stroke cycle diesel engines.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.193-200
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• 2007

Natural gas is one of the most promising alternatives to gasoline and diesel fuels because of its lower harmful emissions, including $CO_2$, and high thermal efficiency. In particular, natural gas is seen as an alternative fuel for heavy-duty Diesel Engines because of the lower resulting emissions of PM, $CO_2$ and $NO_x$. Almost all CNG vehicles use the PFI-type Engine. However, PFI-type CNG Engines have a lower brake horse power, because of reduced volumetric efficiency and lower burning speed. This is a result of gaseous charge and the time losses increase as compared with the DI-type. This study was conducted to investigate the effect of injection conditions (early injection mode, late injection mode) on the combustion phenomena and performances in the or CNG Engine. A DI Diesel Engine with the same specifications used in a previous study was modified to a DI CNG Engine, and injection pressure was constantly kept at 60bar by a two-stage pressure-reducing type regulator. In this study, excess air ratios were varied from 1.0 to the lean limit, at the load conditions 50% throttle open rate and 1700rpm. The combustion characteristics of the or CNG Engine - such as in-cylinder pressure, indicated thermal efficiency, cycle-by-cycle variation, combustion duration and emissions - were investigated. Through this method, it was possible to verify that the combustion duration, the lean limit and the emissions were improved by control of injection timing and the stratified mixture conditions. And combustion duration is affected by not only excess air ratio, injection timing and position of piston but gas flow condition.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.225-230
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• 2017

Coal oil is widely used as a home heating fuel for portable and installed coal oil heaters. Today, Coal oil is widely used as fuel for jet engines and some rocket engines in several grades. This paper describes the performance characteristics according to the compression ratio of spark ignition engine fuelled with coal oil. As a result, the following knowledge is obtained: As the compression ratio is decreased, there is an increase in torque, indicated mean effective pressure (IMEP), heat release rate, and brake thermal efficiency. Higher compression ratio of the engine decreases the ignition delay period, combustion period, and cooling loss.

• 대한기계학회논문집B
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• 제27권5호
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• pp.589-595
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• 2003

DME(Dimethyl ether) is an oxygenated fuel with a octane number higher than that of diesel oil. It meets the ULEV emission regulation and reduces the smoke to almost zero when used in a diesel engine. In the present study, engine performance and exhaust emissions were investigated with a conventional DI diesel engine which has a jerk type injection pump. Test results showed that the power with DME were almost same as that of pure diesel oil, and the brake thermal efficiency increased a little. Also, smoke index from DME engine showed nearly zero level, but NO$_{x}$ was increased compare to diesel oil.

• 수산해양기술연구
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• 제20권2호
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• pp.127-132
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• 1984

(1) 디이젤기관용 대체연료로서 혼합유가 디이젤유의 연료에 대한 특성을 검토하였다. (2) 혼합유로서 디이젤기관을 운전할 경우 배기가스량은 디이젤유보다 평균 8% 정도 많음을 나타내었다. (3) 혼합유로서 디이젤기관을 운전할 경우 디이젤유에 비하여 연료소비량이 약 3% 정도 증가하였다. (4) 정미열효율에 있어서는 디이젤유와 혼합유는 거의 비슷한 상태를 나타내었다.