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Vo Tan Chau,Charoenphonphanich Chinda,Karin Preechar,Susumu Sato,Hidenori Kosaka 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9
Soot and NO x emissions are the inherent combustion characteristics of diesel engines. The modification of fuel property makes for an interesting study of methods for elimination of soot and NO x emissions. HVO and blends of 20 %, 50 %, 80 % by mass of HVO with commercial diesel fuel (mixed 7 % FAME), in combination with various EGR conditions were carried out to evaluate soot and NO xformation, as well as combustion characteristics of HVO blends in RCEM. The obtained results revealed that ignition delay, flame temperature, NO x and soot concentration decreased as HVO percentage increased. Mixing ratios of HVO with diesel showed a similar flame profile at baseline condition, higher flame temperature and darker soot density-KL regions were distributed on the upstream of spray flame. HVO displayed a slightly lower in-flame temperature and KL density, which led to a decrease of 33 % and 15.9 % of NO x and soot concentration, respectively, compared to diesel. By applying higher EGR levels, a reduction of heat release rate, flame temperature and NO x emissions were recorded. Also observed was an increase in ignition delay and soot concentration. Notably, soot at 10 % O 2concentration was lower than that of 15 % O 2 concentration.
Pop-Paul Ewphun,Chau Tan Vo,Prathan Srichai,Chinda Charoenphonphanich,Susumu Sato,Hidenori Kosaka 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.4
This paper investigates the effects of Hydrotreated vegetable oil-diesel blend to combustion characteristics under various ambient oxygen concentrations and ambient pressure. Combustion characteristics were investigated using heat release rate analysis, two color method, soot concentration measurement and NOx concentration measurement. The experiments were carried out on a rapid compression expansion machine to simulate the ambient condition of a CI engine at TDC. Synthetic gas with oxygen concentrations of 21 %, 15 % and 10 % were used to simulate EGR conditions. A single hole injector was used with five different fuels: commercial diesel, HVO-commercial diesel blends and HVO. The results showed that increasing HVO blending percentages decreased ignition delay, flame temperature, soot concentration and NOx concentration. Heat release at oxygen concentration of 10 % dramatically dropped due to a shortened ignition delay, which resulted in less combustion. A decreased oxygen concentration from applied EGR conditions not only increased ignition delay, heat release, flame temperature and NOx concentration, but also increased soot concentration. A combination of EGR and supercharged conditions by increasing ambient pressure and decreasing oxygen concentrations resulted in increased heat release, decreased flame temperature, ignition delay and soot concentration, compared to EGR conditions.