General Motors Regenerative Braking Technology
Regenerative Braking is a form of GM electric vehicle technology for EVs and PHEVs alike. The tech can be found in GM products as early as the 2011 Chevrolet Volt, which was the debut model year for the world’s first mass-produced electric vehicle with extended range.
Notably, Regenerative Braking On Demand – or Regen On Demand as it is referred to – utilizes the regenerative braking mechanism to offer drivers a customizable one-pedal driving experience that allows for maximum total vehicle range. The technology can be found in vehicles as early as the 2014 Cadillac ELR, and a revised four-mode version was released with the arrival of the 2017 Chevrolet Bolt EV.
How It Works
In most applications, the front brakes include an electro-hydraulic regenerative brake system that captures braking energy, which is normally wasted in a conventional vehicle, and transfers it to (i.e. charges) the battery system. The friction braking system features large rotors with a special finishing process that protects against corrosion and promotes longer life.
To clarify, the resistance between the motor and generator – a.k.a. opposing magnetic forces between rotor and stator – is akin to the friction generated by engine braking, which soaks up a vehicle’s kinetic energy. In the case of regen braking, this energy is captured, inverted, and used to recharge the vehicle’s on-board battery.
The total energy captured and transferred back to the battery will vary upon vehicle application, as does functionality. For instance, the 2011 Chevrolet Volt could capture up to 0.2g for transfer, and similar to the 2014 Spark EV, regenerative braking is used 100 percent of the time to slow the vehicle so long as deceleration does not exceed .3g
Notably, progressively stronger levels of regen braking were introduced with the 2017 Chevrolet Bolt EV and are employed through a series of four driver-selectable modes, which are designated by the corresponding numerical values. Number 1 provides the lowest level of regen braking and requires the use of the brake pedal to bring the vehicle to a complete stop. Numbers 2-4 are progressively stronger one-pedal driving modes that in certain driving situations allow a driver to stop the vehicle without using the brake pedal. (One-pedal modes do not eliminate the need to use the brake pedal altogether, especially in emergency situations.)
The modes coincide with the following functionalities:
- Operating in Drive and
- Easing off the accelerator
- Using the Regen on Demand paddle on the back of the steering wheel
- Operating in Low and
- Easing off the accelerator
- Using the Regen on Demand paddle in tandem
Regenerative Braking offers a range of benefits, including improved efficiency in terms of both brake life and miles per conventional charge as well as enhanced braking performance.
It’s worth highlighting the fact that the EPA does not take regen braking into consideration when performing mileage tests, which has provided owners with real-word gas mileage that surpass the EPA’s official MPG ratings.
In certain applications, regenerative braking allows for what is known as Regen On Demand, or ‘one-pedal driving’, wherein a driver simply lifts off the accelerator pedal to slow the vehicle to a stop. See complete information on Regen On Demand (coming soon).
GM’s regenerative braking technology is offered on the following vehicles:
|Year||Make||Model||Powertrain||Horsepower (hp / kW)||Torque (lb-ft / Nm)|
|2011 – 2015||Chevrolet||Volt||Voltec (1.4L I4 Gas + 17.1 kWh Battery)||149 / 111||273 / 368|
|2016 – 2019||Chevrolet||Volt||Voltec (1.5L I4 Gas + 18.4 kWh Battery)||149 / 111||294 / 398|
|2014||Cadillac||ELR||Voltec (1.4L I4 Gas + 17.1 kWh Battery)||207 / 154||295 / 400|
|2016||Cadillac||ELR||Voltec (1.4L I4 Gas + 17.1 kWh Battery)||233 / 173||373 / 443|
|2017 – 2019||Chevrolet||Bolt EV||60 kWh Battery||200 / 150||266 / 360|
|2020 – Present||Chevrolet||Bolt EV||66 kWh Battery||200 / 150||266 / 360|
|2020 – Present||Chevrolet||Menlo EV||52.5 kWh Battery||148 / 110||258 / 349|
*Note: the above table is in-progress, and is not yet comprehensive.
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- General Motors Regen On Demand Technology