Abstract This study was conducted to investigate PM emissions and performance of SI engines fueled with butanol-methanol-gasoline during air dilution operation. Iso-butanol and methanol were blended with gasoline at volume concentrations of up to 40% (10, 20 vol% iso-butanol and methanol, respectively). The effects of lean mixture on engine performance and PM emissions with blends were investigated to find that the power performance of blended fuels is comparable to that of gasoline. High-proportion blends also showed higher brake thermal efficiency (BTE) than gasoline. The brake specific fuel consumption (BSFC) of blends was also about 10% higher than that of gasoline under stoichiometric conditions; with a lean mixture, a reduction of about 9% in the BSFC of blends was observed. The combustion stability of the blends was reduced relative to that of gasoline. CO emissions from the blends decreased rapidly as the mixture became leaner. The NOx emissions of blended fuels were about 30–50% lower than that of gasoline (lambda >1.15) and decreased rapidly as the mixture grew leaner – a reduction of up to 80% was observed. However, when the excess air ratio was less than 1.15, the NOx emissions were about 30% higher than that of gasoline. The increasing BTE trend of blended fuels was similar to that of gasoline as the load increased. A significant reduction in PM concentration was observed during lean mixture operation, which was further reduced with blended fuels. Reduction of accumulation mode particle was more pronounced for blended fuels relative to nucleation mode particles. The total surface area concentration markedly decreased due to a reduction in particle diameter and total concentration. These results altogether suggest that lean mixture reduces PM emissions of blends and improves BTE; n-butanol/methanol addition also contributed to higher BTE and lower gaseous and PM emissions.

中文翻译：

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生物丁醇-甲醇-汽油混合物的颗粒物 (PM) 排放和性能与 SI 发动机中的空气稀释相结合

摘要 本研究旨在研究以丁醇-甲醇-汽油为燃料的 SI 发动机在空气稀释操作期间的 PM 排放和性能。异丁醇和甲醇以高达 40% 的体积浓度（分别为 10%、20% 的异丁醇和甲醇）与汽油混合。研究了混合稀薄混合物对发动机性能和 PM 排放的影响，发现混合燃料的动力性能与汽油相当。高比例的混合物还表现出比汽油更高的制动热效率 (BTE)。在化学计量条件下，混合燃料的制动比燃料消耗（BSFC）也比汽油高约 10%；对于贫混合物，观察到共混物的 BSFC 减少了约 9%。与汽油相比，共混物的燃烧稳定性降低。随着混合物变得更稀薄，来自混合物的 CO 排放量迅速减少。混合燃料的 NOx 排放量比汽油（λ > 1.15）低约 30-50%，并且随着混合物变得更稀薄而迅速减少——观察到减少高达 80%。但是，当空气过剩率小于 1.15 时，NOx 排放量比汽油高 30%左右。随着负荷的增加，混合燃料的 BTE 增加趋势与汽油相似。在稀混合气运行期间观察到 PM 浓度显着降低，混合燃料进一步降低。与成核模式粒子相比，混合燃料的累积模式粒子减少更为明显。由于粒径和总浓度的降低，总表面积浓度显着降低。这些结果表明，稀混合气减少了混合物的 PM 排放并提高了 BTE；添加正丁醇/甲醇也有助于提高 BTE 和降低气体和 PM 排放。