Nissan Minivan Uses Braking to Power Electronics

Nissan Motor Co. has debuted a regenerative braking system whose output is used to power the vehicle's 12-volt accessories.

Called S-Hybrid, the system will be available only in the $30,000 Serena minivan sold in Japan. Nissan has not indicated whether it will offer the technology elsewhere.

The heart of the S-Hybrid powertrain is an upgraded stop-start motor. At vehicle startup, the motor is used to ignite the van's piston engine. Under braking, the engine cuts out, and the stop-start motor becomes an electrical generator.

In spite of its name, the $1,900 S-Hybrid system never uses electricity to propel the vehicle. But making "free" electricity during braking frees the gasoline engine from using some of its power to make electricity with an alternator. Nissan figures the reduced engine load translates into as much as 10% better fuel economy.

Mazda Motor Corp. will introduce a similar regenerative braking system, which it calls i-Eloop, in the Mazda6 sedan next year. The system will use electricity stored in a capacitor to run the car's lights, fuel pump, air conditioning and engine control unit.