Optimization of Idle Vibration Characteristics of Powertrain Mounting System

<div>To address the issue of engine jitter at idle conditions in a specific vehicle model, an initial test of the inertial parameters of the powertrain mounting system was conducted. Utilizing the Adams software, a system model was constructed and subjected to modal analysis. The stiffness of the mounting components was selected as the optimization variable. A deterministic multi-objective optimization was performed on the system’s decoupling rate, natural frequencies, and minimum dynamic reaction force, employing the multi-island genetic algorithm. sensitivity analysis regarding the stiffness of the mounts was conducted based on DOE method. The optimized stiffness values were then re-entered into the Adams software. The results of the deterministic optimization indicated a significant enhancement in the decoupling rate of the powertrain mounting system in the primary direction of concern, a reduction in the natural frequencies, and a decrease to 43.5% of the original scheme in the minimum dynamic force transmitted to the vehicle body. A comparative analysis was conducted on the acceleration amplitude–frequency curves before and after optimization in the <i>Z</i>-direction under idle conditions, and the dynamic reaction force amplitude–frequency curves in three dimensions, both demonstrating a notable attenuation post-optimization. In addition, vibration isolation tests were performed on the powertrain mounting system, comparing the comprehensive isolation rates before and after optimization under idle conditions, with the results fulfilling corporate standards. Finally, based on the stiffness values post-deterministic optimization, robust optimization was conducted employing the 6σ methodology. A robustness analysis of the powertrain energy decoupling rate was performed utilizing the Monte Carlo simulation method, effectively mitigating the tremor issue of the vehicle model under idle conditions.</div>