汽油在O_2/CO_2氛围下燃烧特性的试验研究

Experiment Investigation on Combustion Characteristics of Gasoline in O_2/CO_2 Atmosphere

基于定容燃烧可视化光学平台,模拟缸内直喷(GDI)汽油机缸内燃烧环境,研究汽油在O_2/CO_2氛围和空气氛围下均质燃烧特性以及火焰传播特性。研究结果表明当循环喷油量一定时,相比于空气氛围,汽油在氧气浓度为40%的O_2/CO_2氛围下燃烧的压力升高率提高了1.8倍,着火落后期和明显燃烧期缩短近50%,放热率的峰值增大了近1倍;且峰值相位提前。过量空气系数对汽油在O_2/CO_2氛围下燃烧的影响较大,化学当量比时放热率的峰值达到最大。随着过量空气系数增大,最大燃烧压力增大,最大压力升高率下降,放热率的峰值下降,且峰值相位后移,反应速率下降,明显燃烧期增大,且火焰传播速度明显下降。

Based on the visualization platform of constant volume combustion visualization,air is replaced byO2/CO2 mixture as the intake gas, experimental study on the effects of O2/CO2 atmosbhere on combustion characteristics and flame propagation characteristics of gasoline homogeneous combustion was conducted. Results showthat when the fuel injection quantity is constant and the oxygen percentage of O2/CO2 atmosppressure rise rate increased by 1.8 times,the flame developing duration and the combustion duration short enednearly half, the peak heat release rate increased by nearly 1 time, and the peak phase advance, which relativelycompared with that under air atmosphere in this study. In O2/CO2 atmosphere, the maximum when the stoichiometric ratio, with the increase of excess air coefficient,the maximum combustion pressure increases, however, the peak pressure rise rate decreases,the peak heat release rate decreases and thepeak phase moves backward, the combustion period increases obviously, and the flame propagation speed decreases obviously.