Frontloading of Driveline design

Solution for NVH simulations of transmissions and drivelines

Optimizing NVH attribute of powertrain development

The role of NVH simulation for transmissions is increasingly important in view of strict NVH targets. AVL offers NVH simulation solutions that are based on reliable CAE models and allow consistent predictions already at an early stage of the development.

The Challenge

The engine downsizing strategy and increasing torque demand lead to higher torsional accelerations at lower speeds of the ICE.

  • How do the engine excitations of downsized engines affect different transmission families (3 shaft MT, DCT, DHT)?
  • How can noise be reduced at an early stage of the development?
  • How can we reduce the lead time and still achieve reliable NVH results together with other major attributes (weight, efficiency)?
  • How can we manage the absence of masking noise in electric drivelines?

The AVL Solution

AVL’s NVH simulations are based on a multi-body dynamics CAE approach and they have been validated by measurements - which allows excellent correlations. Detailed 3D NVH optimization is based on accurate excitations (ICE or eMotor), detailed gear tooth contact (Advanced Gear Joint AVL EXCITE tool) and the elasticity of components (via Flex joint) is modelled.

The simulations cover 3 major aspects of vibrations in one tool: Source - Transfer – Radiation. This enables frontloading and early prediction of NVH issues.

AVL’s state-of-the-art NVH evaluation is done and compared with benchmark data from different transmission families, which allows optimization of transmission design parameters. In addition, Air Borne Noise calculations are carried out to study and include the effects of radiation efficiency of structures.

The Added Value

  • Frontloading of NVH optimization already in the development stage results in advantages with regards to function, quality, cost and development time
  • As there is always a trade-off between different transmission attributes - a balance between NVH, efficiency and weight targets of housing can be met thanks to the in-depth analysis.
  •  E-machine excitation and its influence on transmission vibrations are studied within the workflow.
  • Proven troubleshooting experience in solving NVH problems with appropriate root cause analysis based on simulation and measurements