Abstract: This paper mainly studies the problem of seat jitter under idle conditions, identifies the time-frequency characteristics of regular jitter and irregular jitter, and analyzes the mechanism and main influencing factors of the two types of jitter. To solve the problem of irregular jitter, it is clear that the engine combustion stability has a greater influence on irregular jitter, and the engine combustion torque has a smaller influence on jitter. The experiment verifies the trend of idle jitter under different ignition advance angles and different carbon tank operating frequencies. Through the case of A vehicle irregular jitter problem, the control suggestions of engine combustion stability and combustion parameters are put forward. Aiming at the problem of idle speed rule jitter, the beat vibration of engine and transmission is determined to be the main incentive of rule jitter, and the mechanism of the beat vibration is analyzed. Based on the case of the rule jitter problem of a type B vehicle, the design suggestions of assembly rigid body mode and engine shaft frequency avoidance are put forward.

Key words: idle dithering; combustion stability; ignition advance angle; rigid body mode

摘要： 文章主要研究车辆怠速工况下座椅抖动的问题，识别怠速规则抖动与不规则抖动的时 频特征，分析两类抖动产生的机理和主要影响因素。针对不规则抖动问题，明确发动机燃烧 稳定性对不规则抖动影响较大，发动机燃烧扭矩大小对抖动影响较小，试验验证不同点火提 前角和不同碳罐工作频率下怠速抖动变化趋势。通过某 A 款车不规则抖动问题案例，提出发 动机燃烧稳定性和燃烧参数的控制建议。针对怠速规则抖动问题，确定发动机与变速器的拍 振是规则抖动主要激励，分析拍振产生的机理，指出动力总成刚体模态对规则抖动有较大影 响。通过某 B 款车规则抖动问题案例，提出总成刚体模态与发动机轴频避频的设计建议。

关键词: 怠速抖动；燃烧稳定性；点火提前角；刚体模态