天然抗氧化剂对生物柴油燃烧特性的影响研究

针对生物柴油氧化安定性较差的特点,在调和油B20中添加天然抗氧化剂,改善生物柴油的氧化安定性.通过发动机台架试验,测量了标定转速、不同负荷时,分别添加迷迭香与茶多酚两种抗氧化剂的生物柴油K1B20和K2B20的示功图,并与燃用柴油B0、生物柴油B100以及调和油B20进行对比,探讨了抗氧化剂对柴油机燃烧过程的影响.结果表明:低负荷时,与燃用B0相比,燃用B100的最高燃烧压力、最大压力升高率升高,瞬时放热率峰值降低,滞燃期缩短,燃烧持续期延长;与燃用B20相比,燃用K1B20和K2B20的压力曲线与瞬时放热率曲线形状以及燃烧特性参数基本相同.全负荷时,随生物柴油掺混比的增加,最高燃烧压力降低;燃用K1B20和K2B20的最高燃烧压力升高,对应的曲轴转角略有延迟,最大压力升高率峰值基本相同,对应曲轴转角延迟.燃用K1B20和K2B20对柴油机的输出功率影响不大,与B20相比,滞燃期与燃烧持续期略有缩短,排气温度有所降低.

Effects of Natural Antioxidants on Biodiesel Combustion Characteristics

In view of the poor oxidation stability of biodiesel ,the antioxidants were added into B20 mixed fuel .Then the indi-cator diagrams of K1B20 and K2B20 biodiesel mixed with rosemary extract and tea polyphenols respectively were measured un-der different loads at rated speed on a test bench and compared with those of B 0 diesel ,B100 biodiesel and B20 mixed fuel to de-termine the effects of antioxidants on combustionprocess of diesel engine .The results show that the maximum combustion pres-sure decreases ,the maximum pressure rise rate increases ,the ignition delay period shortens and the combustion duration pro-longs at low load and the maximum combustion pressure decreases with the increase of biodiesel proportion at full load when compared with B0 .Compared with B20 ,the maximum combustion pressure of K1B20 and K2B20 increases ,the peak pressure rise rate keeps the same and their corresponding crank angles delay .In addition ,the output power hardly changes ,the ignition delay period and combustion duration shortens slightly ,and the exhaust temperature shows a minor decrease .