Research on the Telegraphic Sound of a Hybrid Electric Vehicle When Starting at Low Temperature

In low temperature environment, some parts of hybrid electric vehicles are affected by temperature, and the performance is completely different from normal temperature. This paper analyses and studies the telegraphic sound of a hybrid electric vehicle when starting at low temperature. First of all, we explored the boundary conditions of telegraph sound, and found that it was strongly related to temperature. We used vibration and noise equipment to locate the single parts, and then simulated the boundary conditions of the whole vehicle on the platform, and stably repeated the problem. Finally, we tested the size of key parts and found that because the rear bearing was pressed incorrectly, clearance was generated. The bearing was subjected to additional axial force, resulting in friction between the inner and outer rings of the bearing. In addition, at low temperature, lubricating oil viscosity becomes larger, bearing clearance becomes smaller, aggravating friction. After more than ten minutes of operation, the temperature rises, the lubrication becomes better, the bearing clearance becomes larger, and the problem is weakened and not perceived.