摘要
为降低CNG发动机NOx排放量,采用负阀重叠的方式,利用AVL-Fire软件对CNG发动机燃烧特性进行仿真研究。仿真结果表明:通过负阀重叠可以实现废气滞留,增大负阀重叠角可以增大缸内EGR率,但会使得进入缸内的新鲜工质减少;随着负阀重叠角的增加,缸内最大爆发压力及最高温度逐渐降低,这有利于降低NOx的排放量,但会导致发动机功率有所下降;采用负阀重叠后,缸内温度及NOx排放量显著下降,并且随着负阀重叠角的增加,缸内温度及NOx排放量逐渐降低。
In order to reduce the exhaust of NOx of compressed natural gas(CNG) engine, using AVL-Fire software simulation studies on combustion characteristics of CNG engine with Negative Valve Overlap(NVO). The simulation results show that, the exhaust gas trap can be achieved by NVO and the exhaust gas recirculation(EGR) rate increases gradually as the NVO increases, but decreases the intake of fresh gas. The maximum pressure and temperature in cylinder reduces gradually as the NVO increases, which is beneficial to reduce the exhaust of NOx, but can lead to engine power declined. The temperature and the exhaust of NOx reduce sharply by taking NVO, and decreases gradually as the NVO increases.
出处
《内燃机》
2014年第6期52-55,共4页
Internal Combustion Engines
基金
国家863计划课题"下一代天然气发动机关键技术与产品开发"(2012AA111718)
关键词
CNG发动机
负阀重叠
内部EGR
仿真研究
CNG engine
negative valve overlap
internal exhaust gas recirculation
simulation study
