Self-regulated compression and expansion effect on spray and mixing of a vibration gasoline combustor under ignition fluctuation

As a new type of combustor, the asymmetric vibrating combustor (AVC) converts thermal and electrical energy through mechanical vibration. However, the effect of ignition position (IP) on AVC fuel spray and mixing remains unexplored. This paper presents a novel full-cycle coupling model that integrates vibration, spray, mixing, ignition, and combustion, and proposes an iterative algorithm to capture the strong coupling between piston dynamics and combustion. Using this model, IP values from 0 to 5 mm are investigated. The results reveal a nonlinear first-improve-then-deteriorate trend: at IP = 3 mm, the in-cylinder conditions are optimal, yielding the largest fuel evaporation, minimal wall impingement, smallest Sauter mean diameter, and the most uniform equivalence ratio distribution (MUI: 83 % in-cylinder, 98.1 % near the spark plug). The key contribution is the identification of IP = 3 mm as the position that achieves the best balance between spray atomization, mixture uniformity, and ignition reliability within the investigated range, thereby improving combustion stability.