Renault has officially opened a new noise vibration and harshness (NVH) unit devoted to the acoustic treatment of powertrains at its technical centre in Lardy.

This is claimed to be one of the most state-of-the-art facilities of its kind in Europe, bringing together vibro-acoustic testing and measurement procedures, including test cells for the study of noise and vibration, a semi-anechoic rolling road, an acyclic test cell for the drivetrain, and a listening room.

Vehicle engineers can calculate the vibro-acoustic performance and characteristics of engines and gearboxes, very early in a project and with minimum delay. The objective is to improve the noise quality of powertrains across the entire range.

With the new unit, Renault claims to be breaking new ground in the understanding of vibro-acoustic phenomena. Dedicated to the acoustic treatment of engines and gearboxes, the new facility will help establish a “sound identity” for all Renault’s powertrains. The objective is to work noise quality into the genetic make-up of the powertrain range upstream of the development phase.

Renault now has a facility devoted to both vibration performance and noise radiation. Measurements and analyses will be carried out on different kinds of noise, whether transmitted mechanically or aerially. One of the major advantages of the NVH unit is that it houses all the vibro-acoustics knowledge and technical facilities under one roof, which will help reduce the time needed to ascertain the vibro-acoustic characteristics and performance of powertrains under development.

The teams will conduct work in the area of low frequencies (below 200 Hz) and mid-range frequencies (between 200 Hz and 1000 Hz), an area in which Renault has already gained far-reaching expertise. In addition to the further strengthening of this knowledge, the unit will work on less well understood phenomena. In particular, this will involve developing measurement and calculation techniques for complex phenomena, in the high-frequency range and during transient-load engine operation (for example, combustion noise).

The fruit of benchmarking conducted with vehicle manufacturers worldwide, the NVH unit brings together latest-generation noise and vibration test facilities. The technological centrepiece is the acyclic drivetrain test bed, which employs an electric generator able to reproduce the acyclic operation of an internal combustion engine.

This is the first test bed of its type to enter service in Europe. The test beds devoted to acoustic measurements have been specially designed so that they are subject to no external or internal noise interference whatever (from ventilation, lights, fluids, etc.). In addition, the semi-anechoic rooms are separated from the rest of the building by means of an isolating “mattress”. The listening room helps analyse reactions to mechanical noises and subject them to jury testing.

The NVH staff work in close collaboration with NVH teams based at the Cléon factory and at the technical centre in Rueil, France. The NVH unit represents an investment of €25 million and employs more than 80 engineers and technicians over a surface area of 6,000 sq. m. It began operations in May 2005.