Honda reveals a suite of green technologies at Tokyo Motor show

Honda announced a lineup of new powertrains featuring a suite of fuel-efficient technologies at the Tokyo Motor Show. Similar to Mazda's SkyActiv branding campaign, Honda will dub the new engine and transmission technology EarthDreams. Likewise, rather than being a single advancement, this new name represents several developments that promise to improve fuel economy.

The new engines range include an entry-level four-cylinder, a new V6, and perhaps most importantly, a new full-hybrid system--a first for Honda. EarthDreams will also incorporate two new transmissions, a continuously variable unit slated to be the primary automatic transmission in most of the Honda and Acura lineups, and a new conventional automatic.

The new hybrid system will use two motors to allow the development of Honda's first plug-in hybrid in 2012 and a traditional hybrid in 2013. (It's not clear whether these dates are for U.S. introductions.) The new plug-in hybrid will have three driving modes: electric, gas, and hybrid. The gas mode can be used to preserve the battery charge. For instance, if you have a long highway commute to a city, this would allow you to save the battery for driving within the city where the electric benefits are greater. The hybrid mode works like a conventional hybrid for more efficient around town and highway driving. And the electric only mode will work as long as the battery charge lasts. Honda says the new system will debut in a midsized car.

For hybrid SUVs and other large hybrids, Honda has developed a new electric version of its SH-AWD all-wheel-drive system. The new system employs two electric motors to power the rear axle, rather than a mechanical system, and it employs a newly developed twin-clutch automated manual transmission that mechanically drives the front wheels.

EarthDreams technologies will appear in gasoline-fueled engines in a wide range of vehicles. Among the technologies are direct injection and a new variable valve timing scheme Honda is calling VTC, which can switch the engine from an efficient Atkinson cycle for highway cruising to a standard Otto cycle for better power in the city. All the new four-cylinder engines will use double-overhead camshafts (instead of a single one today). Both four and six-cylinder engines will shed pounds.

Honda is also developing a new smaller diesel engine for overseas markets.

Honda says its new CVT minimizes the "rubber banding" that consumers have complained about in many of its older CVTs. It will replace traditional automatic transmissions in all but sports sedans and other sporty models.

Honda has also revealed two new concept cars (plus a tiny commuter box for Japan.) The first is an all-electric roadster in the vein of the S2000, with a claimed 100-mile range. The other is a concept version of the new plug-in hybrid sedan.

We are curious to see how these new technologies are integrated into future models.

—Eric Evarts