Diagnostics Meets Design: The Bold New World of NVH Testing

Originally published within Automotive Testing Technology International magazine here.

E-mobility is this generation’s automotive disruptor. Its impact on the industry is on par with the introduction of space travel technology to the aerospace industry, which occurred over the last century. It is also a new direction with unlimited potential. The Burke Porter Group, a family of intelligent manufacturing brands in over 40 locations across four continents, is serious about its commitment to e-vehicle testing and advanced manufacturing markets – for this century and beyond.

Looking at the growth of e-technology through the lens of NVH (noise, vibration, harshness) testing reveals the breadth and complexity of the challenges facing auto makers. Markus Gattermann, technical director from Burke Porter Group brand  H. Kleinknecht & Co. GmbH (Kleinknecht), explains: “To bring cars onto the street that are high-quality, that can be driven many miles with one battery charge is a very big challenge. The entire industry is being asked to find answers to questions that we did not have 15 years ago.”

A multitude of forces are raising these questions and are shaping the trajectory of e-mobility, among them: new materials, new technologies, new laws, new energy sources, new social movements, new customer demands, interior noise, exterior noise, adding noise, faking noise, removing noise, and changing noise. It is not an exaggeration to say that NVH testing will be tested like never before. With the installation of over 13,000 automotive testing systems worldwide, the Burke Porter Group is gathering a trove of data and field experience to support the industry as it takes on these challenges.

As a testing specialist, Kleinknecht is a microcosm of the energy and creativity that is defining the industry. They are an engineering hotbed of “firsts.” This group pioneered the first end of line test stands for Double Clutch Transmission (DCT), as well as battery electric vehicles. Recently, they built a custom machine with two input and two output drive shafts – another first.

The auto industry is also a tale of two masters: the push for new technology and heightened consumer demands. Gattermann from Kleinknecht, a Burke Porter Group brand, takes the argument straight down to the road. “Drivers of fuel engine cars want the experience of a modern car, but they still want to hear a big motor. These same drivers, when they are in an e-car, they think in a completely new direction – the car must be absolutely quiet.”

While public opinion is influencing the direction of e-mobility, without question, the more consequential challenges to the industry are being revealed at the NVH testing bench. Removing a noisy fuel engine has given rise to many complications. Suddenly there are new sounds to contend with: road noises, aerodynamic noises, metal noises, but also noises that circle back to the e-battery, battery cooling systems, gear boxes and e-powertrains.

There are riddles to be solved. Among them, striking a balance between driving distance and the driver’s acoustic experience. Weight reduction translates into greater driving distance, but weight reduction may also affect the actions of the battery and other e-design components. Vehicle noise is not simple or singular. Gattermann summarizes, “Every working part makes some noise. And the challenge is to bring the vehicle into a sensory ‘reality’ where we don’t hear the noise.”

While it’s easy to get lost in the mind-space of creating a desired acoustic signature, Gattermann is quick to bring NVH testing back down to the real-world of diagnostics. “If the e-motor and the e-gears are not correct, then I have a much bigger problem than a car with a little bit of noise.” Gattermann continues,

Gattermann has a point. Historically, NVH testing is a diagnostic process, but its role is expanding. Testing functions and sound design are coming together in new ways to solve many of the new challenges facing auto makers. Designing the driver experience will mean working backwards to materials and engineering. “Everything contributes to the sound of the vehicle,” Gattermann explains, “and the best way to meet these challenges is from a ‘whole-vehicle’ perspective.” Kleinknecht’s technical director is speaking from experience. A holistic view of auto design and engineering is embedded deep in the DNA of the Burke Porter Group’s German brand. The testing specialists have been servicing major European OE’s for over 70 years.

Creating the optimal driving experience utilizing e-vehicle components is a necessary pursuit for the industry. Solving this puzzle, however, just gets the manufacturers in the game. The game is still not won. Gattermann explains: “Creating a viable vehicle that can be driven distances and have power to run air conditioning and all the smart systems expected in a modern car, while still preserving a quiet driving experience, is still the industry’s greatest challenge. To answer these problems, the industry must look into new materials and new areas as never before.”

It is already beginning. Metal companies are forging thinner metals, better plastics are coming out of research labs, and auto makers are building with recycled materials. New battery technology is booming in the form of refillable batteries, dual battery packs and new battery materials. Charging station infrastructure demands are gaining traction. E-mobility is launching a slew of new industries and new technologies.

Today, the sound of innovation is… no sound, but silence may prove to be a fad. Gattermann summarizes, “The technological advancements required to increase driving distance and add power to e-vehicles may alter the auto acoustics in ways that can’t even be imagined at this time.”