This study investigates the influence of EGR (exhaust gas recirculation) coupled with injection pressure on the combustion and emission characteristics of an engine fueled with methanol-gasoline blends. Increasing the methanol blending ratio can improve the knocking phenomenon, BTE (brake thermal efficiency) and regulated emissions. As the methanol blending ratio increases, the optimal fuel injection pressure for achieving the optimal combustion process, BTE and CO (carbon monoxide) emissions increases. The optimal EGR rate for achieving the highest BTE also increases. As the methanol blending ratio increases, the optimal injection pressure for achieving the lowest TPN (total particle number) and NPN (nucleation mode particle number) also increases. Increasing the fuel injection pressure leads to a decrease in APN (accumulation mode particle number). Increasing the methanol blending ratio and EGR rate can reduce TPN and NPN. With increasing methanol blending ratio, APN initially increases and then decreases. When using a lower methanol blending ratio, increasing the EGR rate leads to a higher proportion of APN to TPN. However, when using a higher methanol blending ratio, the opposite is true. The optimal engine performance can be achieved by using M100 fuel with a 35 MPa injection pressure and a 30% EGR rate.

中文翻译：

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废气再循环与喷油压力耦合对甲醇汽油混合发动机燃烧和排放特性的影响

本研究调查了 EGR（废气再循环）与喷射压力对甲醇汽油混合物发动机燃烧和排放特性的影响。提高甲醇混合比例可以改善爆震现象、BTE（制动热效率）和调节排放。随着甲醇混合比例的增加，实现最佳燃烧过程的最佳燃油喷射压力、BTE和CO（一氧化碳）排放量增加。实现最高 BTE 的最佳 EGR 率也会增加。随着甲醇混合比例的增加，实现最低TPN（总颗粒数）和NPN（成核模式颗粒数）的最佳注射压力也增加。增加燃油喷射压力会导致APN（累积模式颗粒数）减少。提高甲醇混合比和EGR率可以降低TPN和NPN。随着甲醇掺混比例的增加，APN先增大后减小。当使用较低的甲醇混合比时，增加EGR率会导致APN与TPN的比例较高。然而，当使用较高的甲醇混合比例时，情况正好相反。使用M100燃油，喷射压力为35 MPa，EGR率为30%，可以实现最佳的发动机性能。