manufacturers in what Bryan calls 'comfort surfaces' - tracks designed not for durability work, but for the analysis and refinement of NVH inputs. Millbrook has introduced new laboratory techniques to analyse specific areas of input, even looking at items as detailed as the 'durability of click quality' for indicator stalks.

Investments have also been made in a new generation of data collection and analysis systems. “The biggest developments in NVH instrumentation have been in the analysis software,” explains NVH engineer Nick Navas. “The latest systems allow more data to be analysed more quickly, helping us to focus on specific frequency ranges that are important to the feel and sound of the vehicle.”

“Vehicle engineers now need a very good understanding of their brand,” says Bryan. “With modern design and analysis systems, it is possible to map the NVH inputs at each point in the drive cycle. A lot of the work we are doing in NVH now supports this modelling by providing real-world data that enhances the accuracy

of the models and predicts how NVH signatures will change over time.”

Millbrook is also applying this expertise to hybrid and electric vehicles. One of the barriers to increased market acceptance is undoubtedly how they sound. Customers changing from a V6 to a four cylinder hybrid may get comparable performance, but at the moment they don't get anything like a comparable sound track.

“Not many years ago, the introduction of increasingly rigorous pass-by noise legislation was thought to have brought an end to cars with aural character but, as usual, a range of competing solutions have been developed such as exhaust bypass valves,” says Bryan. “These techniques have to be applied to downsized engines if they are to acquire the aural and tactile qualities that people desire. It may be that as with, say, the integration of pedestrian impact requirements into front end styling, the result is a new design language, a new sound and feel. Developing this new NVH language is going to be one of the big challenges for the next generation of low-emission powertrains.”