燃料馏程和燃烧相位对柴油机低温燃烧和排放的影响

Effects of Fuel Distillation and Combustion Phase on Diesel Engine Low Temperature Combustion and Emissions

通过一台改装的6缸增压直喷式柴油机,调整喷油正时实现燃烧相位的调节,在不同燃烧相位下开展了宽馏程燃油低温燃烧和排放特性的试验.结果表明:随初馏点的降低,燃料中汽油轻质馏分增加,燃料十六烷值降低,滞燃期延长,预混合气量增加,NO_x和碳烟排放均得到有效改善,但初馏点过低会导致HC和CO排放增加.随CA,50的延后,碳烟和HC排放增加,CO和NO_x排放降低.燃烧相位和宽馏程燃油特性相结合,可以在保证指示热效率的前提下,实现柴油机燃烧和排放的优化,达到同时降低NO_x和碳烟排放的目的.

Experimental study on the effects of combustion phase CA,50 on the low temperature combustion and emissions of a modified six-cylinder turbocharged direct-injection diesel engine fueled with wide distillation range fuel was conducted.Results show that,with the decrease of initial boiling point,light gasoline fractions are increased,cetane number is decreased,and ignition delay is increased.This increases the premixed combustion proportion and results in NO_x and smoke reduction.However,low initial boiling point significantly increases the HC and CO emissions.With the retard of CA,50, emissions of NO_x and soot increase while emissions of HC and CO decrease.Coupling combustion phase with wide distillation range fuel,a reduction in NO_x and smoke emissions can be achieved without lowering the indicate thermal efficiency.