Electric vehicles are quiet. Too quiet, say legislators, thereby posing a risk to pedestrians and cyclists. So new legislation is swinging into force next year mandating all hybrid and EVs to generate a certain level of noise when travelling electric at low speeds. We discuss the implications of these new sound regulations and the opportunities they present to OEMs with Harman's Rajus Augustine, Global Director of Business Development for HALOsonic - Harman's suite of active noise management technologies.
Could you give us an overview of the legislation coming into force around sounds for hybrid and electric vehicles in EU?
Certainly. By mid-2019, all newly developed HEVs [Hybrid Electric Vehicles] and EVs [Electric Vehicles] in Europe should have minimum external sound criteria to meet when travelling using electric propulsion under 20kmph. Depending on driving conditions these vehicles will have to reach a minimum sound pressure in certain frequency bands to make them safer for pedestrians and cyclists when travelling at low speeds.
This marks an important step forward in the HEV and EV markets, both from a safety and experiential perspective. At low speeds, HEVs and EVs often cannot be heard – we miss the sound of the combustion engine that has become familiar and gives acoustic cues to understand when a vehicle is approaching. These acoustic cues also help to determine the direction from which a vehicle is travelling and how close it is.
This lack of noise in HEVs and EVs is particularly problematic for the elderly, children, cyclists, the blind and their guide dogs that are conditioned to listen for cars. The risks are even higher in slow speed areas such as car parks, with research in the US highlighting pedestrians are twice as likely to be knocked over by an EV or HEV as compared to an internal combustion (IC) engine car. Thus, on one hand OEMs must adhere to these regulatory requirements, and on the other hand, they need to find a way to make the sound appealing to the car-buyer and unique such that their brand DNA is retained.
Harman has been helping OEMs since 2015 to help ensure pedestrian safety. The HALOsonic external Electronic Sound Synthesis (eESS) feature creates an electronic sound that is projected from external speakers at the front and/or rear of the electric vehicle to warn pedestrians of its approach.
What are the limitations of the sound within the regulations? What kind of sound does it have to be? Can it be anything?
Regulations are very specific when it comes to the sound meeting specific octave band levels. The sound as such must be continuous, and the characteristic can vary. For example, it could be the sound of an internal combustion engine or a 'Star Wars-esque' drone but it has to be recognised as a moving vehicle and can neither be natural (e.g. sound of rain, waves, animals), alarms (e.g. sirens, chimes, bells) nor melodies.
OEMs increasingly want to use this sound to help reflect their brand DNA.
Moreover, OEMs increasingly want to use this sound to help reflect their brand DNA. Additionally, they are looking to differentiate the sound of their carlines from one another. For example, the external sound for a sporty hybrid car could be different from the external sound of a family hybrid even when they are produced by the same OEM.
How complex are OEMs finding it to add this external sound generating technology?
The technology is well proven and relatively simple to integrate as far as external sound generation is concerned. Harman identified the need for external sound to cover for lack of noise in EVs and HEVs around 2009 and developed eESS, long before the legislations were proposed. Ever since we have been able to expand our technology offering to make it more feature rich and efficient. For example, in case of sporty hybrid cars, our solutions enable OEMs to replicate the characteristic exhilarating sporty sound associated with the sports car when it is in electric mode. Moreover, eESS also helps ensure that the sporty engine sound of the car transitions seamlessly as the hybrid car's electronic control unit (ECU) switches between IC engine and the electric motor, in its pursuit to reduce fuel consumption and CO2 emissions.
Today, Harman HALOsonic offers our OEM partners a one-stop shop for active noise management technologies – be it taking away the noise you don't want to hear inside the cabin using technologies such as HALOsonic Road Noise Cancellation (RNC), Engine Order Cancellation (EOC) or adding-in the sound that you want to hear inside and/or outside the cabin: internal Electronic Sound Synthesis (iESS) or external Electronic Sound Synthesis (eESS).
HALOsonic is modular in that it can just deliver iESS, eESS, RNC, EOC or all of these technologies combined into a single offering. OEMs that are taking a holistic approach to managing noise better find our comprehensive offering, coming from one single supplier, much simpler to tune and integrate. Our in-cabin noise management technologies typically use the standard speakers that come with the car, whether it is deploying RNC, EOC or iESS and our audio amplifiers can do the processing for generating as well as suppressing sounds. This makes for a smaller, lighter system, both critical must-haves for the OEM as far as EVs and HEVs are concerned. Finally, and most importantly Harman's Global Tuning Tool offers OEM partners engaged in tuning of active noise cancellation technologies and audio technologies a seamless experience, despite these activities embedded within different OEM teams.
You mentioned Road Noise Cancellation. What is driving that and can HALOsonic help?
Fundamentally, road noise cancellation pertains to reducing the road impact-induced noise in the car cabin as these impact vibrations transition from the tyres, through the chassis and suspension onto the passengers in the car.
As you know, OEMs are increasingly looking at ways and means to improve drive range for electric cars - the lighter the car, the higher the range. Weight reduction measures include deployment of lightweight structural materials. Unfortunately, deployment of such material compromise ability to dampen out noise inside the cabin.
Additionally, increasing usage of lower profile tyres with stiffer sidewalls and multi-link suspension systems all have an adverse impact on in-cabin noise. In case of pure electric vehicles, road noise is significantly predominant inside the cabin, given there is no engine noise to mask the road noise. This noise generated from tyres and the road create a droning sound that can contribute to driver drowsiness.
HALOsonic can counter these noise impacts through deployment of the RNC feature, making the cabin quieter and more comfortable. Using signals received from accelerometers placed at the suspension and chassis, the system predicts the noises that will be transferred into the cabin and creates an inverse noise wave that cancels out the drone.
Does that also consider engine noise or just road noise?
HALOsonic can also handle unwanted engine noise. Harman's EOC technology uses the engine RPM signal as a reference to generate a sound wave that is opposite in phase to the engine induced low-frequency noise. Error microphones mounted in the cabin ceiling provide feedback on the amplitude and phase to refine noise-cancelling effects.
here has been
of some trends in our industry of engine sound affecting the perception of
. If we think of a four-cylinder version of a car that was downsized to three-cylinders or a V8 car subject to attenuation due to regulations as they are perceived to be too loud. Can HALOsonic help here?
Customers expect cars to provide an emotional response and make the driving experience exhilarating.
Absolutely. Customers expect cars to provide an emotional response and make the driving experience exhilarating. A rich engine sound is an integral part of being behind the wheel and plays an indispensable role in defining a car's DNA.
Think of some of the most iconic cars like a V8 Mustang, V12 Ferrari and the growl of a Subaru. Engine downsizing and usage of turbochargers to improve engine efficiency adversely impact these iconic sounds.
Moreover, in order to avoid noise pollution, pass-by-noise regulations mandate OEMs to ensure that the engine sound outside the car remains within stipulated limits.
HALOsonic technologies such as EOC and iESS help bring back that desirable enriching engine sound inside the cabin. Whilst our OEM partners focus on defining and attaining the target sound that reflects the brand DNA of their cars, we provide them with the tools and technologies to help them attain as authentic a sound as possible in the most efficient manner.
I guess the same must be true for EVs that perhaps do not have a sound signature?
In future, sound could be a real brand differentiator.
Yes. OEMs see the need to create a sound that reflects their brand DNA, and this could become a way to differentiate manufacturers. Traditionally, external sound associated with a car has been limited to its engine noise. In case of HEVs and EVs, Harman's sound tuning tools allow our OEM partners to design 'sound signatures' to differentiate their brand and even their models. Signature sounds could mean that pedestrians are able to distinguish a brand without even seeing the vehicle. We all know the Intel sound signature and the audio that opens a Walt Disney film; this concept could filter through to our roads. In future, sound could be a real brand differentiator.
So it's clear that sound is important externally but do you think that sound is important for a driver of a hybrid or electric car?
Certainly. Today, when you sit in an electric car all you need is to push the pedal and the car starts rolling. There is no typical engine sound and the car is more or less silent as it starts moving at first. The rolling of the car without any acoustic feedback tends to take people by surprise, especially because human beings are accustomed to acoustic feedback when it comes to a "moving car". In such scenarios, OEMs typically look to deploy a "welcome sound" to help ensure that the driver knows the car is good to roll.
Moreover, as I mentioned before, in case of sporty hybrid cars, it is important that the passengers experience a smooth sound transition as the ECU switches from the sporty sound of IC engine to the relatively silent electric motor.
With the ever-increasing electrification evolution pursued by OEMs globally, a signature sound for these silent machines will be a predominant part of the differentiation and driving experience. HALOsonic with its broad spectrum of active noise management technologies is positioned to give a voice to these cars – be it inside or outside the car.
Source : https://www.just-auto.com/interview/pitch-perfect-harman-hits-the-right-note-on-evs_id181649.aspx