Ever since the first electric hybrids were on the road, many people have been questioning how safe they really are. These worries are not about the crash test reliability, but rather the lack of noise the vehicles make when cruising down the road. While several aftermarket companies have presented solutions, Lotus Engineering is no working on a system that provides the necessary engine noise to the outside, while also reducing noise in the cabin.
The system itself is actually three smaller systems that work in conjunction to create the safest and most comfortable driving experience. The first two systems, called Road Noise Cancellation (RNC) and Engine Order Cancellation (EOC), will work to eliminate the noises that often pollute the cabin of the vehicle. RNC uses a system of sensors mounted on the suspension components of the vehicle to monitor the amount and type of noise coming from the road. EOC will make use of a set of signals from the engine, most likely engine speed, current gear and road speed, which are then sent to a central processor where data from the RNC system is also sent.
There are also several microphones located inside the cabin area that will be collecting information on the amount of background noise that is being generated. Once all the data has been compiled, the entertainment system inside you vehicle is then used to produce a specific frequency or set of frequencies that will almost completely cancel out noise from the road and the engine. All of this happens in a few thousandths of a second and repeats constantly to adapt to changes in road conditions and engine variations.
In case you are worried, the noise canceling system will not interfere with conversation or the music you are listening to at the time.
Interestingly enough, Lotus is also working on a system to place in hybrids, called Electronic Sound Synthesis (ESS) that will serve as a means of warning pedestrians of an oncoming vehicle. When operating in full electric mode, a small water-proof speaker located on the outside of will generate a tone while your speakers on the inside will provide "realistic" engine feedback that is dependent on throttle position and engine speed. The system is also fully customizable; meaning your electric plug-in could sound like a high end supercar, if you really want to make that happen.
The systems can all be used at the same time, or any one can be employed separately, depending on the wants/needs of the buyer. Presently, Lotus has licensed the rights to manufacture and distribute all three systems to Harman Becker International for the OEM market worldwide.