GM's newest plug-in hybrid, a.k.a. electric vehicle with extended range, the 2014 Cadillac ELR, will come with an adjustable regenerative braking system literally at the drivers finger tips. Where some electric cars offer adjustable regenerative braking, by using buttons on the dashboard, the Cadillac ELR has "paddles" on the steering wheel to adjust regenerative braking. This is different from normal steering wheel-mounted paddles that allow drivers to upshift for more performance.
The feature, called Regen on Demand, is engaged in a straight-forward way. First the driver takes his or her foot off the accelerator, and second pulls back on either the left or right steering-wheel paddle. At that point the drive train will begin regenerating electricity, and slowing the ELR down.
Regenerative braking is available on most electric cars, and converts momentum (speed) into electricity to recharge the battery pack. Because it removes momentum from the car, it slows down as if the driver pressed the mechanical brakes. With mechanical brakes momentum is converted into heat, in the brake pads.
This behavior is possible on electric cars because electric motors can also be used as generators, with the spinning wheels causing the force necessary to operate the motor as a generator. It's one of the advantages electric cars have over gasoline cars, in that gasoline cars cannot regenerate fuel while slowing down.
The Cadillac ELR has a blended regenerative and mechanical braking system that's initiated in the usual way, via the brake pedal. That system, as in most electric cars, uses regenerative braking as much as possible, resorting to mechanical braking for stronger stops. Because the regenerative braking system does not give a full stop, some mechanical braking is used in all stops.
What the paddle activated Regen On Demand system does is offer another way to engage the regenerative braking system.
The system has a standard 4-channel anti-lock braking system and includes electronic Brake Force Distribution, which uses independent rear control for improved stability and braking during cornering, as well as more effective use of the rear brakes as vehicle loading occurs.
“Regen on Demand enables ELR drivers to actively re-capture energy when slowing down, such as when approaching slower traffic or setting up for a tight turn,” said Chris Thomason, ELR chief engineer. “This allows the driver to take more active role in the electric vehicle driving experience. Pulling back on the paddle to slow down allows the ELR driver to keep their foot close to the throttle, ready to accelerate. It provides a more engaged, satisfying driving experience, and when you consider the added benefit of re-capturing energy, it’s also a smart thing to do.”