摘要
An engine cyclic variation model has been built by using the residual gas temperature for the n th cycle as the input of the model, through constant pressure intake process, adiabatic compression process, constant volume combustion process, adiabatic expansion process, adiabatic blow down process and constant pressure exhaust process to approximate the thermodynamic processes in the cylinder, finally the residual gas temperature for the ( n+1) th cycle can be estimated. Because of the adding of engine operating parameters such as engine speed, spark advance, equivalence ratio, intake air pressure, intake air temperature to the model, effects of these parameters on cyclic variation can be estimated quantitatively. Since residual gas temperature fluctuation between cycles reflects the circumstances of engine cyclic variation, parameters to which residual gas temperature is sensitive are most likely used as the means to control cyclic variation. Model simulation shows that for the nearly stiochiometric mixture, cyclic variation is not obvious or even quite stable, but for the lean mixture, under the circumstances of partial load and larger spark advances, engine cyclic variations occur chaotically or with bifurcation.
基于循环间变动的排气温度建立了一个发动机循环变动模型 .在这个模型中 ,第n个循环的排气温度作为模型的输入 ,通过定压进气过程、绝热压缩过程、定容燃烧过程、绝热膨胀过程、定容放热过程和定压排气过程来近似汽缸内的热力学过程 ,最后得出第n +1个循环的排气温度 .由于把发动机运行参数 ,如转速、点火角、计量比、进气压力和进气温度等加入该模型 ,可定量地估计这些参数对发动机循环变动的影响 .因为循环间排气温度的波动反映了循环变动程度 ,对排气温度影响最敏感的参数最可能被用于循环变动控制 .模型仿真结果表明 ,对于接近化学计量比的混合气 ,循环变动不明显 ,对于稀薄混合气 ,在部分负荷和较大点火角的情况下 。
基金
SouthernCaliforniaAirQualityManagementDistrict
