甲醇/生物柴油/F-T柴油煤基多元燃料对柴油机燃烧及排放性能的影响

Effects of Methanol/Biodiesel/F-T Diesel Coal-Based Multi-Fuels on Engine Performance

为寻找柴油清洁替代燃料，选用F-T柴油、甲醇两种煤基燃料，并结合生物柴油，配制成甲醇（methanol）/生物柴油（biodiesel）/F-T柴油（F-T）煤基多元燃料（简称MBFT燃料）。在未经改动的增压直喷式发动机上，通过试验分析了MBFT燃料的性能，研究了甲醇比例对MBFT燃料性能的影响规律。研究结果表明：MBFT燃料的燃烧特性介于0#柴油与F-T/油之间，甲醇比例对MBFT燃料的燃烧特性产生直接的影响，随着甲醇比例增大，预混燃烧量与扩散燃烧量比值增大；在动力经济性方面，相比于0#柴油，MBFT燃料的动力性降低了7.5%~9.5%，但燃油经济性提升了6.6%~11.3%，随着甲醇比例增大，MBFT燃料在动力性下降的同时，燃油经济性也变差，因此甲醇的体积比例不宜超过10%；关于排放性能，MBFT燃料可以在F-T柴油的基础上，进一步优化排放中氮氧化物（NOx）与碳烟之间的折中关系，不同甲醇比例的MBFT燃料对排放的改善效果基本一致。

In order to search for clean alternative fuels for diesel, two coal-based fuels including F-T diesel and methanol were choosed and mixed with biodiesel to confect into methanol/biodiesel/F-T diesel multi-fuel （MBFT）. An unchanged turbo-charging and direct-injection engine was operated with three multi-fuels to study their performance and discuss the influence rules of methanol proportion on the performance of MBFT fuels. Results indicate that MBFT fuels perform an eclectic combustion mode between 0# diesel and F-T diesel. Furthermore, the methanol proportion makes a difference to the combustion characteristics directly. With more methanol addition, MBFT fuels characterize more premixed combustion and less diffusive combustion. When MBFT fuels are compared with 0# diesel, engine power and fuel economy, the engine power decreased by 7.5%~9.5%, but fuel economy improves by 6.6%~11.3%. More methanol content in blended fuels would cause the worse fuel economy and less output power. When it comes to the emissions, MBFT can further improve the trade-off relation between NOx and soot emissions in the foundation of F-T diesel. MBFT fuels with different methanol proportion exert a similar effect on the improvement of emissions.