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 Z-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.
