Sound Generators for EVs

Sound Generators for EVs

The good news about electric vehicles (EVs) is that they’re quiet. The bad news about EVs is that they’re quiet, so much so that when traveling at low speeds, like in neighborhoods or school zones, they’re silent enough to go undetected to the human ear, potentially catching pedestrians off guard. In fact, the U.S. Congress passed a bill in 2010 to make noise-generating devices mandatory on all silent-running vehicles. Delphi (delphi.com) has developed two eco-friendly sound generators, or “sounders,” for application in EVs that kick in when the vehicles are moving at 20 to 30 mph:

• Electronic Sounder System: A single-box system that’s three times lighter and 90% more energy-efficient than conventional multi-box systems. Provides a frequency range of 500Hz to 10 kHz.
• High-fidelity Sounder System: Uses a magnet-activated cone speaker to generate noise. Weighs 66% less than conventional speaker systems. Operates at a frequency of 150 Hz.

Both systems feature a 32-bit microprocessor with flash memory. They’re robustly designed to be embedded under the hood in all vehicle platforms. Additionally, they’re designed to allow vehicle manufacturers to customize the sound they generate.

While there’s no production date presently set for the High-fidelity Sounder, the Electronic Sounder System is scheduled to go into production in Europe in 2012.

Delphi’s sound generator systems enable pedestrians to detect hybrid and electric vehicles at would-be silent 20-30 mph speeds.

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EPBs for Front Axles

Although electric park brakes (EPBs) have been in produc-tion since 2001, there are two things to consider with them: (1) Almost all of today’s EPBs are rear-axle systems and (2) They’re costly and generally applied only to larger, more-expensive vehicles.

So TRW (trw.com) has developed a new EPB. It’s an affordable, compact system for front axles, so it has the potential for applications in non-lux vehicles. Like rear-axle systems, TRW’s EPB enhances emergency braking performance in the event of hydraulic failure. However, it can be installed with minimal modifications to front axle calipers, which makes it more affordable and applicable across a wider range of vehicles. Additional comfort and safety features such as hill and drive away assist, electronically controlled deceleration and rollaway detection, can also be included with the system.

The EPB is expected to launch in 2013.