Study on Mount Matching Optimization for Removing Powertrain Abnormal Low Frequency Vibration
Research Objective For abnormal engine vibration due to hidden engine design defects, manufacturing error or mount mismatching, the priority should be to re-match the mount, which is the easiest way to solve this hard problem. In this study, it focuses on engine mount matching research, and the torque roll axis (TRA) decoupling method is applied to remove low-frequency intermittent traverse of an engine model. Methodology With the measured inertia characteristics of the engine powertrain, the TRA theory is used to calculate the direction of TRA. It is indicated in the TRA complete decoupling theory that it is theoretically possible if a pure TRA mode is implemented, torque vibration along crankshaft only produces roll vibration along TRA. However, other loads exist on engine-mounts system. So, a large decouple rate along TRA with acceptable decouple rate in other directions is a priority in guiding further adjustment on installation location, installation angle and stiffness of the four engine mounts. Then, energy decoupling theory is used to calculate the decouple rate after optimization, to validate whether the vibration direction with large excitation energy has been decoupled to the greatest extent. Results According to TRA decoupling calculation with experimental results, slight adjustments on the engine mount installation location, installation angle and stiffness can remove the abnormal low-frequency vibration Phenomenon tremendously, and promote NVH performance of the vehicle. Limitations of this study It is found that multiple hydraulic mounts can remarkably improve the performance of low frequency vibration isolation, but worsen the vehicle noise performance. If active mount control method can be applied jointly, it is prospective that the mount matching performance could be optimal. What does the paper offer that is new in the field including in comparison to other work by the authors? A new optimization idea for engine-mounts decoupling method is applied. With a large decouple rate along TRA and acceptable decouple rate in other directions, the phenomenon of abnormal low-frequency vibration can be eliminated. Conclusion TRA Mount Matching Optimization Methods can greatly improve the abnormal low frequency vibration of the powertrain system.
KeywordsMount matching Low-frequency Vibration Torque roll axis Decouple
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