Mazda has developed a regenerative braking system for use in their gasoline powered vehicles that will boost fuel efficiency as much as 10 percent. The Mazda system uses a variable voltage alternator to recapture energy from the vehicle as it slows. The alternator voltage varies from 12 to 25 volts direct current (DC). As soon as the driver’s foot is removed from the accelerator, deceleration forces are captured via the alternator and sent to a specially designed capacitor for storage. This low-resistance capacitor has been developed to provide the capability of being fully charged in seconds. Next in line is a DC-DC converter that steps the stored power down from 25 volts to 12 volts which is then used to power auxiliary systems such as the climate control and audio systems.
According to Mazda, the capacitor can be charged and discharged quickly and is resistant to deterioration over prolonged use. If you are reading this and wondering why Nissan (or others) aren’t using this technology in their electric vehicles (EVs), it is because the capacitor capacity is not enough currently to power a vehicle. Capacitor technology and lithium-air battery technology, as well as other battery technology, is being studied by universities, corporations and likely advanced technology hobbyists in search of longer range capabilities for EVs. Affordable application of these technologies is still many years off.
Mazda claims that in start-stop driving conditions (think in town or stop and go commute traffic) this technology can improve fuel efficiency by 10 percent. Makes sense. In steady state driving conditions (steady freeway cruising), there is little deceleration from which to capture energy.
Mazda expects to launch this technology in Europe and the United Kingdom in the spring of 2012. The initial vehicle to sport the technology will be the CX-5 SUV. In our view, anything that advances energy efficiency is a good thing.