增压直喷汽油机中润滑油液滴诱发早燃机制的数值研究

发布时间：2018-06-16 20:04

本文选题：增压直喷汽油机 + 早燃　；参考：《西安交通大学学报》2016年07期

【摘要】：通过利用多维计算流体动力学(CFD)耦合一个多组分汽油替代物的骨架反应机理,对增压直喷汽油机中润滑油液滴诱发早燃的机制进行了研究。首先,在模拟增压高强化汽油机压缩上止点热力学状态的定容圆柱网格内,研究了润滑油液滴的存在对汽油/空气混合气自燃过程的影响,结果表明:以正庚烷和过氧氢酮分别作为润滑油蒸发产物时润滑油液滴的存在均可缩短混合气的着火延迟时间,尤其是以过氧氢酮作为润滑油蒸发产物时混合气的着火延迟时间缩短更为明显;随着润滑油液滴粒径的增大,混合气的着火延迟时间先缩短后延长,润滑油液滴温度和混合气的温度、压力升高会进一步缩短混合气的着火延迟时间。然后,以过氧氢酮作为润滑油蒸发产物,在增压直喷汽油机动网格内模拟了润滑油液滴存在时缸内混合气的自燃过程,结果表明:润滑油液滴蒸发释放出了着火性能较好的组分,缩短了液滴周围混合气的着火延迟时间,导致液滴周围混合气在火花点火之前自燃,从而引发早燃。最后,根据以上结论提出了一个润滑油液滴诱发早燃的机制。
[Abstract]:The mechanism of early combustion induced by lubricating oil droplets in a turbocharged direct injection gasoline engine was studied by coupling the skeleton reaction mechanism of a multicomponent gasoline substitute with multi-dimensional computational fluid dynamics (CFDs). Firstly, the influence of the presence of lubricating oil droplets on the spontaneous combustion of gasoline / air mixture was studied in a constant volume cylindrical grid simulating the thermodynamic state of the compression of a turbocharged and high intensified gasoline engine. The results show that the ignition delay time of the mixture can be shortened by the presence of the lubricating oil droplets when n-heptane and peroxyhydrogen ketone are used as the vaporizing products of the lubricating oil, respectively. Especially when peroxyhydrogen ketone is used as the product of lubricating oil evaporation, the ignition delay time of the mixture decreases more obviously, and the ignition delay time of the mixture decreases first and then prolongs with the increase of the size of the lubricating oil droplet. The ignition delay time of the mixture will be further shortened by increasing the temperature of the lubricating oil droplet and the temperature and pressure of the mixture. Then, the spontaneous combustion process of the mixture in cylinder was simulated in the dynamic grid of turbocharged direct injection gasoline engine with peroxyhydrogen ketone as the product of lubricating oil evaporation. The results show that the vaporization of the lubricating oil droplets releases the components with better ignition performance, shortens the ignition delay time of the mixture around the droplets, and causes the mixture around the droplets to self-ignite before the spark ignites, thus causing the early combustion. Finally, based on the above conclusions, a mechanism of early combustion induced by lubricating oil droplets is proposed.
【作者单位】：西安交通大学能源与动力工程学院;一汽解放汽车有限公司无锡柴油机厂;
【基金】：国家自然科学基金资助项目(50776069) 陕西省自然科学基金资助项目(2015JM5236)
【分类号】：TK411.2

【相似文献】