Experimental Research On Combustion And Emission Of Mixed Biofuel On Diesel Engine

As energy crisis aggravating and the increasingly tougher emission regulations, the development of new fuel has become one focus in the study of internal combustion engine. This paper studies from the aspects of fuel quality to improve agricultural small diesel engine combustion characteristics and emission performance without changing the structure and the parameters of fuel supply, agricultural small direct injection diesel engine.This paper selects the fuels:tung oil, colza oil,configuring pure biofuels, biofuels accounted for large proportion of fuels and biofuels accounted for a small proportion of the fuels and conducts load characteristic test on ZS195diesel engine, studying the influence of the biofuels (tung oil, rapeseed oil and ethanol) and its ratio on combustion and heat release regularity and emission performance of the diesel engine.Experimental results show that different oils and different proportions of mixed fuels has obvious effect on combustion characteristics and emissions performance of diesel engine.In the small load condition,comparing with0#diesel oil, the combustion and heat release of the pure biofuels and biofuels accounted for large proportion of the fuel obviously lag (1-4°CA), the ignition delay period extend, the peak of cylinder pressure and heat release rate rise, the pressure increases by5%, and the heat release rate increases by9%at most, the performance of the tung oil is more obvious, the performance of biofuel blended with ethanol is also more obvious. As the load increasing,combustion starting point goes ahead, the ignition delay period gradually shortened as0#diesel,the heat release rate reduce by19%at most, the curve of pressure curve is almost the same as0#diesel.The cold-start performance of Pure biological fuel and biofuels accounted for large proportion is poor, but both can satisfy the requirement of power performance, the fuel economy is slightly lower, fuel consumption rate is12-18%, higher than diesel in declared working condition.In terms of emissions:NOx emissions reduced by about10%when burning pure biofuel, biofuels accounted for large proportion of fuels blended with ethanol, NOx emissions of the mixed fuel reduced by15%. in almost every point soot of biofuels and biofuels accounted for large proportion of fuel are lower than biofuels reduce by89%at most. At rated condition NOx emissions of Biofuels accounted for the small proportion of fuels reduce by8.8%at most and the smoke emission (N) reduced by76%at most. The results show that biofuels and their blended fuel can satisfy the requirements of the power and fuel economy performance of diesel engine and the combustion characteristic at rated condition is good, the engine is running smoothly, can effectively reduce the main diesel engine emissions:NOx emissions and smoke emissions. Results show that the overall effect of biofuels and their blended fuel and the biofuels accounted for large proportion of fuel is the best.