2014 Mazda 6 wagon makes Paris motor show debut
Mazda showed off its new Mazda 6 wagon today at the Paris motor show, adding a bit of convenience to the latest vehicle that receives the company's SkyActiv treatment. As in the CX-5 compact crossover, SkyActiv technologies in the Mazda 6 include engine, transmission, body and suspension design changes that are meant to improve fuel economy.
Of more interest is Mazda's new brake energy regeneration system, termed “i-ELOOP” (intelligent Energy Loop.) The system uses a capacitor to store electricity generated during deceleration and braking to power the vehicle's electrical systems. Reusing that energy lessens the load on the alternator and improves fuel economy.
Why a capacitor? Batteries generally charge comparatively slowly and inefficiently; it's not a major drawback during constant operation, but when just a few seconds of regenerative braking are being captured, a battery is less efficient than Mazda's electric double-layer capacitor (EDLC), which recharges fully within only a few seconds. The power is generated by a variable-voltage alternator, and a full capacitor charge can run things like the climate control and audio systems for a minute or so.
It may not sound like much, but in real-world driving the minute of charge is often enough to power the vehicle without the battery during engine-off operation (in stop-start mode). Mazda claims i-ELOOP can produce most of the vehicle's electrical power in normal driving conditions, freeing up the power normally used to drive the alternator.
Like the Mazda 6 wagon itself, the i-ELOOP system won't be headed stateside for the foreseeable future. While wagons are something of a risky bet in the modern domestic market, there's a more straightforward reason that Mazda will not be installing i-ELOOP in vehicles bound for America: The current EPA testing cycle does not recognize fuel economy gains that capacitor-based regeneration systems can provide.

