Study On Combustion And Emissions Characteristics Of Diesel Engine Fuelled With Acidification Biodiesel

As increasingly prominent energy and pollution problems, the study of alternative fuels becomes more meaningful, biodiesel is one of them. Compared with traditional diesel, biodiesel is environmental friendly, oxygenic, renewable, easily degradable, lubricating and safe, etc, it can be blended directly without changing engine structure. Acidification biodiesel is a kind of biodiesel, its raw material is niger of refining oil, the development and application of acidification biodiesel improves the utilization rate of raw materials, which has social and economic benefits.The topic research of biodiesel fuel is acidification biodiesel. At first the physical and chemical properties and ingredients were tested and contrastively analyzed the properties, then focused on the influence of working condition, mixing ratio, fuel injection timing and EGR on the combustion, economy and emission performance through the experiment. The results showed that:on the CRDI engine, with the increase of blending ratio, the maximum combustion pressure little changed, the peak heat release rate first increased and then decreased, the maximum temperature slightly increased, combustion start point delayed and combustion duration shortened, the effective specific fuel consumption of blending fuels increased, CO emissions increased, HC and soot emissions reduced, HC reduced up to 36%, soot reduced up to 22%, NOX emissions slightly rose but lower than diesel, NOX of blended fuel reduced up to 7%.Under the same injection timing, with the increase of blending ratio, combustion duration shortened, effective specific fuel consumption increased, HC emissions reduced and when fuel injection advance angle was-3.31°CA, HC of blended fuel redeuced 3% to 8%, CO emissions increased, NOX emissions slightly increased but lower than diesel. With the delay of fuel injection timing, the maximum combustion pressure reduced, combustion duration shortened, HC emissions increased, CO emissions first decreased and then increased, NOX emissions decreased.With the increase of EGR valve opening, the maximum combustion pressure, the peak heat release rate, the maximum temperature decreased, combustion duration extended, effective specific fuel consumption increased, HC and CO emissions increased, NOX emissions decreased.