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RISS 인기검색어
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- 저자 : Hekun Jia (검색결과 5 건)
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Energy Management Strategy of Fuel Cell/Battery Hybrid Vehicle Based on Series Fuzzy Control
Jia Hekun,Tang Jiexu,Yu Yingxiao,Sun Yan,Yin Bifeng,Zhang Chao 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.6
Fuel cell durability and vehicle operating cost are the main optimization goals of energy management strategy (EMS) for fuel cell hybrid electric vehicles (FCHEV). In this paper, a series fuzzy control strategy (SFCS) is proposed to decrease the load changing rate of fuel cell system (FCs). The test bench is used to obtain the output characteristics and load changing capacity of FCs. In order to increase the driving mileage and to eliminate the uncertainty of manual experience in fuzzy controller, particle swarm optimization (PSO) is used to optimize the subjection function distribution and rule weights of fuzzy control, and the evaluation function is constructed by operating cost. Based on the experiment data of FC and battery, the model of the vehicle and strategy are constructed in the software environment, and the optimization result is obtained through simulation. The results show that the FCs load changing rate is reduced and limited to the range of change capacity through the SFCS, while the durability of the fuel cell is optimized. The SFCS optimized by PSO (PSFCS) increases the driving mileage. Under WLTC and UDDS conditions, mileage has been increased by 11.2 % and 8.79 % respectively.
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Jia Hekun,Liu Zhiyuan,Yin Bifeng,Zhang Xin,Xu Yi 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.2
Based on a small non-road diesel engine, internal exhaust gas recirculation (IEGR) was realized by the exhaust valve re-opening (2EVO). The influences of IEGR on combustion and emission performance were analyzed. The results showed that in-cylinder pressure peak decreased, the start of heat release was delayed by 0.5 °CA and the heat release rate peak was reduced after the introduction of IEGR. Furthermore, the average temperature of combustion flame was reduced, centering between 1900 and 2100 K. That was beneficial to curbed nitrogen oxides (NOX) emissions. The average value for KL factor was obviously increased within the entire range of combustion, which resulting in an increase in soot emission. In terms of emission characteristics, NOX emission was significantly reduced under the original injection timing but soot emission was increased slightly. Subsequently, the start of injection (SOI) were adjusted based on IEGR and two fuel injection control strategies were formulated from the perspective of reducing pollutant emissions and fuel consumption: Strategy 1 keeping BSFC consistent with the original engine, the NOX+HC weighted emission was reduced by 17.6 %; Strategy 2 keeping NOX+HC emissions consistent with the original engine, BSFC and CO were reduced by 10 % and 20 % respectively and Soot emission was slightly increased.
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Huaping Xu,Bifeng Yin,Shengji Liu,Hekun Jia 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8
The present work is aimed at unfolding the effect of fuel supply parameters such as Fuel injection pressure (FIP), Start of injection timing (SOI), Pilot-main injection intervals (PMII) on performance and emission characteristics of 20 % blend of Jatropha curcas biodiesel (J20) under light load operation of a diesel engine. The experiments were designed using design of experiments based on the fractional factorial design of Response surface methodology (RSM). Multiple regression models developed using RSM for measured responses like nitrogen oxides (NO X ), SOOT, hydrocarbon (HC), Brake specific fuel consumption (BSFC) and Brake thermal efficiency (BTE), were found to be statistically significant by Analysis of variance (ANOVA). Interactive effects among FIP, SOI and PMII were analyzed using response surface graphs that were fitted using developed RSM models. Optimization was performed using the desirability approach of the RSM for lesser emissions and BSFC simultaneously with superior BTE. A FIP of 134.11 MPa, SOI of 6.4 BTDC, and PMII of 5.8 CA were found to be optimal values for J20 in the test engine of 21 kW at 1800 rpm. The results of this study show that at optimal input parameters, the values of the NO X , SOOT, HC, BSFC and BTE with a high desirability of 96.7 % are 603.44 ppm, 0.037 FSN, 12.73 ppm, 233.26 g/kW h and 37.31 %, respectively.
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Study on Tribological Properties of Laser-Textured Plunger in Methanol Engine
Bifeng Yin,Yuhao Jiang,Bo Xu,Hekun Jia,Xuefeng Wang 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4
Considering the eccentricity and deformation of the plunger, a lubrication model of laser-textured plunger pair was established to research friction-and-wear performance of typical surface texture on the plunger under diesel and methanol lubrication. The calculation results show that for the non-textured plunger, the oil film thickness and fluid friction under methanol lubrication are lower than diesel lubrication, and the asperity friction was greater than diesel lubrication, indicating that methanol may deteriorate the lubrication performance of the plunger surface. After texturing the plunger, the oil film thickness and fluid friction during methanol lubrication are greater than the non-textured scheme, and the asperity friction is lower than the non-textured scheme, which means that the surface texture has the potential to improve the lubrication performance of the plunger. The friction and wear tests results indicate that the average friction coefficient of the textured plunger is reduced by 3.4 ~ 6.2 % compared with the non-textured plunger in methanol lubrication. The lubrication performance of the textured plunger during methanol lubrication reaches the level of the non-textured plunger in diesel lubrication. After the wear test, the surface wear depth of the textured plunger is reduced by 16.2 % compared with the non-textured plunger in methanol lubrication condition.
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Huaping Xu,Shengji Liu,Bifeng Yin,Hekun Jia,Shenghao Yu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6
Although exhaust gas recirculation (EGR) is a common way to suppress the nitrogen oxide (NO X ) emissions, it also brings some negative impact on soot emissions and the thermal efficiency in internal combustion engines. We investigated the effects of ambient oxygen concentrations on engine performance, combustion characteristics, and emissions using a four-cylinder diesel engine equipped with an endoscopic visualization system. To estimate the flame temperature and soot distribution, we analyzed these images using a postprocessing program. Experimental results showed that the luminosity of flames in the images was degraded comparatively for the reduced oxygen concentration. Flame temperature distribution also showed similar behavior. As the oxygen concentration decreased, area of soot distribution significantly reduced at IMEP = 0.13 MPa, and only a slight decrease at IMEP = 0.3 MPa. But locally high soot concentration regions increased.
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