Target Setting for Vibration Transmission Through Driveline Components Based on On-Vehicle and On-Bench Evaluation

Abstract

The different connections between the powerplant and vehicle chassis/body should be developed carefully in order to minimise the transfer of unwanted vibrations. The engine mounts are well known to have significant contribution in the total transfer of powertrain noises in a broad frequency band, ranging from low-frequency booming noise to high-frequency gear noises. Also the driveshafts can often be an important contributor.

In order to control the NVH performance during the development of those components, clear component KPI’s and targets are needed. A suitable KPI should fit in a consistent breakdown of the performance, e.g. based on a (simple) model of the considered contribution path. It is shown that an output/input side transmissibility can be a suitable KPI for driveshafts and engine mounting brackets.

In this work, the use of a transmissibility KPI is illustrated on two case studies: one for engine booming noise and one for gear noise. It is shown how the proposed KPI can fit in a robust target cascading process that can be used throughout the different project phases.

Since the final host vehicle is often not available during the component development, it is important that the selected KPI’s can be evaluated on a test bench (or from an isolated component model). The correlation between on-vehicle and on-bench evaluation is reported, including an investigation of the trade-off between evaluation accuracy and bench complexity.