双燃料发动机的燃烧模型

针对双燃料发动机燃烧特性，建立了柴油喷雾扩散燃烧子模型和气体燃烧均质混合气火焰传播燃烧子模型，应用该模型研究了双燃料发动机燃烧机理，计算结果和实验结果相当吻合。计算表明：当引燃柴油比例较大时，双燃料发动机燃烧过程以喷雾混合控制燃烧为主，柴油喷雾扩散燃烧模型与实测较吻合；当柴油比例较小时，该过程以均质混合气火焰传播燃烧为主，均质混合气火焰传播燃烧模型与实测软吻合。计算结果表明，引燃柴油量对双燃料发动机性能影响较大，引燃柴油减少，着火滞燃期延长，缸内最大爆发压力升高。

Combustion Model for Dual Fuel Diesel Engines

According to the combustion characteristics of dual fuel engines,a diesel diffusion combustion sub model and a homogeneous fuel air mixtures flame propagation combustion model have been developed.With this model,the mechanics of dual fuel engine combustion have been investigated.Good agreement between calculated values and experimental values was obtained.The results show that when the pilot fuel quantity is large,the combustion process of dual fuel einges is controlled by pilot fuel mixing,and the diffusion combustion model is more feasible than that for the flame propagation model.But when the pilot fuel quantity is small,the combustion process is controlled by homogeneous fuel air mixtures flame propagation and the flame propagation model is more feasible than that for the diffusion combustion model.In addition,the effect of pilot fuel quantity on the performance of dual fuel engines is studied recurring to this model.With the increase of the pilot fuel quantity,the ignition delay becomes shorter,and the cylinder maximum pressure becomes larger at the middle and low load mode,but it becomes smaller at the full load mode.