One of the key functions necessary to maximize the capability of hybrid
and electric vehicles
is regenerative braking. For those who haven't been paying attention, regenerative braking uses the property of electric motors where mechanically driving the motor causes it to act as a generator producing electric current. In order to facilitate this, a brake system
that can monitor the driver's braking request and then seamlessly blend the maximum amount of regenerative braking with a corresponding amount of friction is needed. All of the major electronic braking system suppliers including Bosch, Continental
Teves and TRW have developed such systems. TRW's system, dubbed Slip Control Boost (SCB) had its first production application on the General Motors
two-mode hybrid SUVs
and the fuel cell Equinox
that is being used for Project Driveway. Because hybrids and EVs
don't necessarily have a vacuum source available for brake boost, the SCB system incorporates a hydraulic brake booster and a high pressure accumulator to supply brake pressure on demand. SCB also provides full slip control functionality, including ABS, traction control and stability control. TRW has just announced a second-generation version SCB2 that is 25 percent smaller and lighter than the original. The SCB2 system can also be used on diesel vehicles
to replace the vacuum pump or hydraulic assist systems for the brakes. This should also be a lower cost which will contribute to automakers reducing the costs of their hybrid and electric vehicles.
Full disclosure: prior to becoming a full-time writer last year, I worked as a controls software engineer at TRW and worked on the original SCB system.