Application Research On Methanol And Diesel Blended Fuels In Diesel Engine

The increase in quantity of possessed vehicles leds to the depletion of oil resources and deterioration of environment. Seeking alternative fuels and reducing vehicle exhaust emissions are of great practical significance. Methanol, as one of the most promising alternative fuels in internal combustion engine, can solve this problem commendably.Methanol and diesel, two substances of opposite polarity, are difficult in solubility with each other at commom temperature, except the fusion of cosolvent. Iso-octanol, as a cosolvent in this paper, is used to make up three different proportions of methanol-diesel blended fuel applied in diesel engine for experimental study. It shows that methanol can improve the combustion in the cylinder, and reduce NOX and soot emissions at the same time. However, because of its low heating value, the power of diesel engine can not reach to the original. Methanol is used to replace diesel fuel as much as possible, while it must maintain the original diesel engine performance. This paper chooses M15 methanol-diesel blended fuel and optimizes the fuel supply parameters, to study the influence on the diesel engine performance by different injection pressures, fuel supply advance angles and fuel delivery. It shows when the injection pressure is 22.5Mpa, fuel supply advance angle is 14℃A BTDC, and the fuel delivery is increased by 9.5%, the engine can basically maintain the original power perfoamance, but the fuel economy is worse than the original engine, the emissions of other pollutants have increased except soot emission, and NOx emissions is increased by 58.5% at the conditon of 3200r/min and 75% load.On the basis, this paper takes EGR technology to reduce the NOx emission for further, studies the effect of different EGR rates on diesel performance, and ascertain the best EGR rates at different conditions. The best EGR rates can maintain the performance and economy of the engine, make the NOx and soot emissions in a lower level, compared with 0# diesel. NOx emission is reduced by 62.7%, and soot emission is reduced by 30.8% at the condition of 1200r/min and 25% load.To reduce the times and cost of experiment, environmental adaptability of diesel engine is studied in GT-POWER software with M15 blended fuel to promote it. It shows that performance of the engine is not obvious on the environmental temperature, but very sensitive to atmospheric pressure changes. M15 blended fuel can be used for military purposes at altitude of about 4000m and all-weather area.