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Nguyen Xuan Khoa(웬수언코아),Ocktaeck Lim(임옥택) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
In this research, we estimated and summarized the effects of combustion duration on performance and emission characteristics of a spark-ignition engine using pure methanol and ethanol as fuels, which has not been previously presented. From the results, we demonstrated that increase of combustion duration causes a decrease in peak firing temperature and peak firing pressure and increase in trapped residual gas. The level of trapped residual gas when using ethanol as fuel is higher than that of methanol fuel. The indicate mean effective pressure (IMEP) and brake mean effective pressure (BMEP) increases to maximum value and then decrease with increasing combustion duration, while the brake specific fuel consumption (BSFC) reaches a minimum value and then increases. The optimal BSFC improved to 33.31% when the engine used ethanol fuel instead of methanol. The increase of combustion duration helps to reduce NOx and HC emission, but an increase in CO emission is observed.
Quach Nhu Y(콱누이),Nguyen Xuan Khoa(웬수언코아),Ocktaeck Lim(임옥택) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
In the present study, the performance and emission characteristics of a natural gas engine were investigated under variable ignition timing and different mixing ratio of natural gas fuel. From the results, the researcher can know the optimal ignition timing value and the best mixing ratio that gives the target engine torque, power, IMEP, NOx and CO emission. To achieve this goal, an experimental system was installed within a dynamo testing system, and a simulation model was established by using Chemkin software. The simulation model was used to determine the in-cylinder pressure, brake specific fuel consumption, peak temperature, and engine emission characteristics in variable ignition timing (21–48 degrees crank angle, BTDC). The engine was tested at 1800 rpm, volume percent of ethane in the methane, ethane, propane blends ranged from 0 to 20%. It is worth noting that the ignition timing and mixing ratio had a significant effect on brake torque, in-cylinder pressure, engine performance, and emission characteristics. The results show that as the percentage of propane in the mixture increases, it increases the peak temperature and peak pressure resulting in an increase in torque, power and IMEP. However, it reduces thermal efficiency and increases fuel consumption. Moreover, when increasing its early ignition time from 21 to 39 degree it will increase power, torque and IMEP but from 42 to 48 degrees it tends to the opposite.