关键词: 间歇性抖动；间歇性抖动机理；燃烧稳定性；喷油截止时刻；振动计量值

Abstract: This article discusses the phenomenon and naming of the intermittent shake of the vehicle. The frequency of the intermittent shake is the rigid body modal frequency of the power train mount, not the half-order of the speed or the half-order of the combustion. The mechanism of intermittent shake and the main transmission path are analyzed. If the engine combustion calibration control is abnormal or the combustion stability is not attended during the calibration development process, it will cause the engine to abnormal combustion, including poor combustion or multi-cylinders misfire, which is the root cause of intermittent shake. Finally, the calibration parameters such as fuel injection control, intake control, and ignition control that have a greater impact on combustion stability are discussed, and commonly used combustion stability indicators and recommended limits are given. Discussed the evaluation method of vehicle intermittent shake, including parameters such as flywheel end angular acceleration, seat vibration peak coefficient and vibration dose value. Finally, combined with the intermittent shake problem of a 1.5 T engine matching a vehicle, the investigation found that the EOIT angle control in the fuel injection control of the engine has a greater impact on the combustion. The combustion stability parameters of the original calibration data are all lower than the recommended limit, optimized EOIT from 65 BDTC to 85 degrees BDTC, the combustion stability parameter meets the combustion stability limit, and the vibration amplitude of the abnormal frequency band is reduced from 10 mg to 2.5 mg, and the drop rate reaches 75%, which solves the intermittent shake of the car. and meet the requirements of emission regulations.

Key words: Intermittent shake; Mechanism of Intermittent shake; Combustion stability; End of injection time; Vibration dose value