(1.School of Automobile & Transportation,Xihua University,Chengdu 610039,China;2.Key Laboratory of Fluid and Power Machinery,Ministry of Education,Chengdu 610039,China)
The effects of oxygen content in blended fuel on combustion and emission of diesel engine were researched under different intake oxygen concentration on a 4cylinder high pressure common rail diesel engine by mixing 0%, 10% and 20% mass faction of nbutanol into diesel respectively. The results show that the ignition delay periods of three blended fuels keep almost constant when the volume fraction of intake air oxygen is between 20% and 21%. The increase of blending ratio leads to the increase of oxygen content of blended fuel so that the ignition delay period prolongs. And the effects of fuel properties on ignition delay period increase with the decrease of oxygen volume fraction of intake air. In addition, the increase of oxygen content improved soot emission and indicated thermal efficiency but had little influence on NOx emission. When the oxygen volume fraction of intake air is lower than 15%, the active effect of oxygen content of blended fuel on indicated thermal efficiency weakens.