Abstract: To improve the suboptimal air-fuel mixture quality found when using n-Butanol fuel in direct injection engines, this study uses a specific engine model as an example and establishes a single-cylinder physical model with 3D computational fluid dynamics (CFD) software, based on the engine’s operational process. The study aims to analyze how various injection timings influence engine performance. The investigation reveals that advancing the injection timing, compared to delayed injection, provides more time for the air and fuel to mix, resulting in a better air-fuel mixture quality. Improved mixture quality leads to increased in-cylinder pressure and decreased emissions of CO, soot, and HC. However, it is imperative to note that this adjustment engenders an increment in the emission of NOX.

Key words: N-Butanol; In-cylinder direct injection; Injection timing; Combustion; Emission

摘要： 为解决正丁醇燃料应用于缸内直喷发动机时易造成混合气质量差的问题，以某款缸内 直喷发动机为例，基于发动机的工作过程，采用三维计算流体力学（CFD）软件搭建了缸内 直喷发动机的单缸物理模型，分析不同喷油正时对发动机性能的影响。研究结果表明，相对 于推迟喷油，提前喷油提供了更多空气与燃料的混合时间，能够获得更好的混合气质量，从 而能够达到较高的缸内压力，并能减少 CO、soot 和 HC 的排放，但 NOX 的排放增加。

关键词: 正丁醇；缸内直喷；喷油正时；燃烧；排放