正丁醇预混合气对轻型柴油机热效率和排放的影响

对1台轻型柴油机进气道进行改装,从而在进气道中形成均质丁醇预混合气。研究了在不同工况下正丁醇预混比对发动机指示热效率和排放的影响。研究结果表明:随着丁醇预混比例的增加,发动机指示热效率呈现上升的趋势,转速为3 350r/min,平均指示压力为1MPa时指示热效率的提升率达到最大为4.3%;压力升高率过大,限制了在大负荷条件下使用更高的丁醇预混比例;随着丁醇预混比例的增加,发动机soot和NO_x排放明显改善,而CO和HC排放均随着丁醇预混比的增加而增大。

Effects of N-butanol Premixed Charge on Indicated Thermal Efficiency and Emission of Light Duty Diesel Engine

In order to form homogeneous premixed air/n-butanol mixture inside intake port,the intake manifold of a light duty diesel engine was modified.The effects of n-butanol premixed ratio on engine indicated thermal efficiency and emissions were studied under different conditions.The results show that the indicated thermal efficiency increases with the increase of n-butanol ratio.The indicated thermal efficiency of diesel/n-butanol compound combustion mode is 4.3％ higher than that of the pure diesel model under the conditions of 3 350 r/min and 1 MPa IMEP.However,the too large pressure rise rate will limit the premix ratio of n-butanol at high load.In addition,the soot and NOx emissions decrease,but the CO and HC emissions increase.