Dave Bogema, Product Manager – NVH Refinement, Brüel & Kjær
Mark Allman-Ward, Senior Application Specialist, Brüel & Kjær
“The VW Dieselgate accelerated the end of the diesel era,” says Giorgio Adriano, Business Development Manager, Automotive, Brüel & Kjær. “Diesel may not be as bad as it’s made out to be, but the result is clear. OEMs are rapidly moving towards electrification, at high costs.”
There’s currently little competition in the electric vehicle (EV) or hybrid (HEV) market, with each vehicle enjoying its own broad segment. But in just five years, the market will close up as more OEMs launch their own hybrid or electric model. Down to the battery’s chemistry and components, there will be little in terms of technology to differentiate vehicles at each price point. That leaves two to three cars at a similar price, and with similar components, range, and performance.
“It’s a technical challenge and a business model challenge,” explains Dave Bogema, Product manager – NVH Refinement, Brüel & Kjær. Millennials are more environmentally conscious and under more economic pressure than the boomers before them. Will upcoming generations buy as many cars? And what will ownership look like in 10 to 20 years? New technologies such as autonomous driving will open up whole new opportunities for ride-sharing and shared-ownership models. “We’re at an inflection point,” says Dave Bogema. “The industry is undergoing a big change – and change goes hand in hand with innovation.”
Sound and vibration as the differentiator
Whether it’s a choice between a purchase or service, an EV or autonomous car, as the market evolves and narrows the user experience will be the ultimate differentiator. As Mark AllmanWard, Senior Application Specialist, Brüel & Kjær, explains: “Aesthetics has traditionally been a key focus area for OEMs – but when you sit in a car, you can’t see its colour! Meanwhile, speed limits cap your max speed and give a similar driving efficiency. That leaves the driving experience as the differentiator: suspension, driving dynamics and noise, vibration and harshness.”
NVH has long played a subtle but important role in the driving experience. From the slam of the car door to the beep of a low fuel warning, the wrong noises can make a car sound cheap and unreliable – regardless of the actual cost and quality. The right noises add a sense of premium quality, and even pleasure and excitement, and the vehicle’s sonic identity can further differentiate the model or brand as a whole. Future trends and technologies bring more opportunities to develop the driving experience through NVH.
The sound of electric
Designing the sound of EVs brings new challenges and opportunities. All cars need to become more efficient. For combustion engines this is to meet tightening fuel regulations, while for EVs it’s about increasing range. But decreasing weight increases noise and discomfort. This poses a particular challenge for electric engines, which make little sound to mask the road and wind noise.
Sound designers need to get creative to make the best user experience for EVs. The sound of a combustion engine is both a familiar and a pleasant one for many drivers. But EVs offer a blank slate and the chance for innovation.
Regulations in both the EU and the US are making warning sounds for pedestrians mandatory. But drivers are also missing crucial feedback from the electric engine, from torque to the basic “Is this thing on?”. This can’t all be done visually – or with more annoying beeps. As Giorgio Adriano describes it, “The sound and haptic feedback should welcome and guide you, from opening the door to sitting down, from pushing the start button to letting you know the car is ready to go and, finally, generating a sound that will make driving that car a unique experience.” We are heading into an age of digital NVH, where the basic sounds of the car can be managed reasonably well by the development teams. The sounds, and to some extent the vibrations, the users experience can then be added late in the development by software or a data upload.
New EU regulations came into force in July 2019, requiring all new electric vehicles to be fitted with an Acoustic Vehicle Alert System (AVAS). In the US, the National Highway Traffic Safety Administration will require all new electric vehicles to emit artificial noise by September 2020. A car’s AVAS must sound when reversing or travelling below 12 mph (19.3 km/h) in the EU or 19 mph (30.5 km/h) in the US.
The driverless driving experience
Communicating through sound and vibration will be even more important with autonomous cars, where there’s less involvement and less trust, especially at the beginning. “We crave information,” says Mark Allman-Ward. “If you’re not involved, you can only process what’s left. Every single sound in the car will be more significant when you’re not driving.” The volume of information available, when you consider car-to-car communication, is set to grow exponentially – some of that will be interesting to occupants, but there will be far too much information to deliver it all visually.
Some people will want to know exactly what the car is doing. Others will want to use the space to work or relax. Sound designers will need to remove unnecessary sound and vibration and consider the best way to convey crucial information. This could be haptic feedback when the car is speeding up or slowing down, or a pleasant sound when riders reach their destination. The whole experience, from seat configuration to sound preferences, can be personalized through explicit or learned feedback.
Developers make changes throughout a vehicle’s development. It is useful to evaluate the effects of alterations and trial alternative design solutions – such as modified components – in a virtual prototype. With Brüel & Kjær’s NVH simulation, it is possible to test the NVH effects of alternative designs back-to-back, without making a physical prototype. Simulations can combine real-world test data and data from Computer Aided Engineering (CAE) models, interfacing with all common CAE codes.
Looking into the future
Simulation in product design and development is becoming more prevalent and more important. Used in the automotive industry for years, simulation is now becoming faster, more accurate, and more heavily relied on. Brüel & Kjær and VI-grade have a unique set of tools to simulate NVH, driving dynamics, and Advanced Driver Assistance Systems (ADAS). The result is a quicker, cheaper development process – increasing development efficiency and reducing time to market. And with a user experience that will make the vehicle stand out in the future market.
“It’s one thing to calculate that a change will be ‘3dB louder’,” says Dave Bogema. “But that doesn’t mean much to most people. What does that sound and feel like? The NVH simulator brings all this data to life so you can make design and develop- ment decisions easily and with confidence.”