The Power of Digital Acoustic Vehicle Alerting System (AVAS) Test

As engineers of electric vehicles (EVs), it's a pivotal time for your industry as it looks to scale and ensure that zero-emission vehicles replace the internal combustion engine. In addition to the environmental benefits, EVs provide performance improvements, including quicker acceleration and quieter operation due to the electric drive shaft.

However, the lack of noise, especially at low speeds, while pleasant for the driver, is a hazard. Audio cues have traditionally alerted people that a vehicle is approaching, but EVs’ silence threatens the safety of pedestrians and other vulnerable road users. Additionally, with people increasingly distracted by their phones, this further increases the likelihood of an accident occurring in busy urban settings. Highlighting the risk, research in the UK identified that pedestrians are twice as likely to be hit by an EV versus a gas-powered vehicle.

The problem is more acute at lower speeds, as once an EV reaches 30 kph (18-20 mph), the noise generated by tires alerts users. To address safety concerns, regulations have been introduced mandating the use of AVAS systems. And while legislation varies between countries, most require alert sounds for EVs traveling below 30 kph to reduce accidents.

Given how vital AVAS are to modern roadway safety, the rigorous testing and vetting of these systems early in the design phase is paramount. EV manufacturers need a way to assess noise and vibration behavior in every scenario the vehicle may encounter—a requirement that traditional physical prototyping can only meet at higher cost. Enter vibro-acoustic simulation: The technology equips engineers with your own “virtual acoustic chamber” to analyze and predict all interior and exterior noise and vibration criteria at every stage of the design cycle. This means you can get EV designs right the first time while simultaneously eliminating the need for costly physical prototypes to test and evaluate AVAS. The benefits include:

• Ensuring regulatory compliance
• Optimizing designs to accelerate development
• Aligning with sustainability goals through reduced testing mileage

Most critically, through simulation engineers can efficiently balance the dueling priorities of external safety requirements and interior comfort. Once these competing needs are met, the roadway to automotive innovation awaits.

Case Study: Nissan's Success with ESI VA ONE

One organization seizing this opportunity is Nissan Motor Corporation. They [1] partnered with ESI to overcome the challenges of AVAS testing with vibro-acoustic simulation—below is a snapshot of the success we’ve realized together.

As mentioned, the regulatory environment is a complicating factor in AVAS testing.  Regulations govern criteria such as the frequency content and the level of the sound emitted. It’s imperative that AVAS sounds comply with vehicle speed, be audible in real-world conditions, and meet specific frequency requirements.

Simply adjusting the volume is not the answer, as it can cause unnecessary noise pollution in areas where the emission was sufficient; instead, companies must utilize technology innovations that predict how the noise generated will move from the speaker to the different evaluation points.  Our VA ONE platform enabled Nissan to do exactly that.

The solution integrates various modeling methods to cover the full frequency spectrum, helping engineers achieve sound balance with vehicles that adhere to the myriad noise regulations while ensuring passenger comfort.

Say goodbye to the days of revving engines. As EV adoption continues, there will be increasingly fewer audio cues to alert vulnerable road users to vehicle movement. This puts the onus on automotive engineers to proactively address safety concerns early in the development process without compromising on passenger comfort.

Vibro-acoustic simulation is an essential technology in this effort, providing unparalleled insight into vehicle noise and vibration behavior at every stage of the design cycle. Not only does this accelerate development and ensure regulatory compliance, it also helps companies meet sustainability goals. Simulation eliminates the need to build multiple physical prototypes, reducing resources, costs and manpower, while also substantially decreasing testing mileage.

It’s the safety benefits that deserve the most recognition, however. With hybrid and electric vehicles posing twice the pedestrian safety threat as their gas-powered counterparts, the technology’s ability to mitigate this risk can’t be overstated. 

As automotive engineers, the power is in your hands. VA ONE offers a unified platform for you to perform accurate predictive noise and vibration assessments early in the design cycle—ensuring you enhance EVs’ acoustic performance.