纳米Al_(2)O_(3)对甲醇/柴油掺混燃料燃烧及排放特性的影响研究

Effect of nano-Al_(2)O_(3)additive on combustion and emission characteristics of diesel engine fuelled with methanol-diesel blends

文章在ZS1100柴油机上研究了甲醇及纳米Al_(2)O_(3)添加剂(0.0025%、0.0050%、0.0100%)对发动机燃烧和排放性能的影响。结果表明:柴油中添加甲醇对发动机缸内峰值压力、放热率峰值以及燃烧始点的影响随负荷而变化,添加甲醇会加速缸内燃烧过程,使各负荷下CA50提前,燃烧热效率增加,但燃油消耗率增加;纳米Al_(2)O_(3)的添加可提高甲醇/柴油掺混燃料缸内压力及放热率峰值,缩短滞燃期,同时有效地改善了燃油经济性,且随着燃油中Al_(2)O_(3)添加量的增加改善越明显;甲醇/柴油掺混燃料中加入纳米Al_(2)O_(3)颗粒后发动机燃油消耗率可降低3.1%,制动热效率提升3.2%;柴油中添加甲醇使发动机CO排放降低,HC及NO_(x)排放增加,碳烟排放减小;添加纳米Al_(2)O_(3)后,发动机NO_(x)排放小幅增加(<10%),而CO、HC和碳烟等排放均有较大幅度的降低,且随着纳米Al_(2)O_(3)添加量的增加,降低幅度越明显;甲醇/柴油掺混燃料中添加0.0100%纳米Al_(2)O_(3)后,发动机CO、HC和碳烟排放分别降低了49.0%、32.4%、47.0%。

This study investigates the effects of methanol and nano-Al_(2)O_(3)additive on combustion and emission characteristics of ZS1100 direct injection diesel engine.The Al_(2)O_(3)nanoparticles were added into the methanol-diesel blends in the mass fractions of 0.0025%,0.0050%and 0.0100%under ultrasonic mixing.The results revealed that the effect of methanol on the peak pressure,peak heat release rate and ignition timing of diesel engine varied with the engine load.However,higher brake thermal efficiency,increased brake specific fuel consumption and earlier CA50 were observed with methanol-diesel blends.The addition of Al_(2)O_(3)nanoparticles to methanol-diesel blends could increase cylinder gas pressure,peak heat release rate and shorten ignition delay period,along with an effective improvement of the fuel economy.Moreover,the larger the amount of Al_(2)O_(3)nanoparticles was,the more obvious improvement could be achieved.The diesel engine operated by nano-Al_(2)O_(3)added methanol-diesel blends enhanced the brake thermal efficiency by 3.2%and reduced brake specific fuel consumption by 3.1%,when compared to those for neat methanol-diesel blends.Furthermore,adding methanol to diesel could reduce CO and smoke emission,whereas increase HC and NO_(x) emission.The addition of nano-Al_(2)O_(3)to methanol-diesel blends showed significantly lower CO,HC and smoke emission,but increased slightly NO_(x) emission(less than 10%).The CO,HC and smoke emission was decreased by 49.0%,32.4%and 47.0%,respectively,for 0.0100%nano-Al_(2)O_(3)dosage in methanol-diesel blends compared to pure methanol-diesel blends.