There are concerns that electric vehicles are too quiet for our roads and this is putting people’s safety at risk. However, this concern that has been answered by Hyundai Mobis, who have developed an artificial engine sound system using the front grill cover of the electric vehicle, thought to be the first in the world. This creative thinking eliminates acousticpressure loss by using the cover as the diaphragm and will be highly useful when communication with pedestrians is so critical.
Unlike internal combustion engine vehicles that have holes in the front grill to let the air flow in, the front of an electric vehicle is completely blocked. Based on this fact, Hyundai Mobis creatively changed the way we think and used the cover itself as a component of the speakers and developed a new system as a result.
“Hyundai Mobis succeeded in reducing the weight by 2/3 and the size by half,” said Kim Tae-woo, head of IVI Product Design Team 2 of Hyundai Mobis. “We simplified the structure and lowered the price by reducing the number of components by more than half, and eliminated the bracket or housing, which fastens different devices, to easily secure space.”
Hyundai Mobis greatly improved the efficiency and performance of this new system compared to existing products and added such functions as the turn signal sound and charging status alarm as well as the artificial engine sound. In keeping with the age of future cars when autonomous driving becomes common, it is necessary to inform pedestrians of the direction in which the vehicle is going or whether it is operating so that they can be prepared in advance. Also, it can be used as speakers for playing music during outdoor activities, such as camping.
Acoustic Vehicle Alert Sound (AVAS) is a speaker system that produces a sound outside of the vehicle so that pedestrians can sense an oncoming environmentally friendly car that emits almost no noise. It is differentiated from ASD which produces an artificial engine sound inside the vehicle for the fun of driving. Governments around the world are making the artificial engine sound system mandatory to prevent accidents involving pedestrians from becoming more common as environmentally friendly cars are too quiet.
This system, developed by Hyundai Mobis, installs the existing product, which used to be installed inside the vehicle in the form of complete speakers, on the back of the grill cover located on the front of the vehicle, in the form of a half-finished product. A speaker consists of the actuator, which generates sound, and the diaphragm, which propagates the sound to the outside. Hyundai Mobis separated the actuator, attached it to the grill cover and used the grill cover as the diaphragm of the speakers. Unlike existing speakers installed inside the electric vehicle with a blocked front, the grill cover, exposed to the outside, produces sound in this system and there is no acoustic pressure loss. So, it is very efficient.
In hybrid cars which have both the engine and motor, the actuator is installed on the back of the front bumper for the same effect. Hyundai Mobis achieved this result only a year after it began development at the end of 2018 and applied for two related patents.