Mazda could be the first automaker to bring a hydrogen-enabled powertrain to the mass market, with a pledge to begin leasing its rotary engine model in 2008.

Mazda will showcase Premacy Hydrogen RE Hybrid five-seater at Tokyo Motor Show this month.

In this case, the “hybrid” not only refers to a mild hybrid system, but also to its dual-fuel powertrain, which uses a rotary engine consuming either gaseous hydrogen or gasoline to power an electric motor.

The Premacy picks up from the Mazda RX-8 Hydrogen RE with its Renesis engine, which directly burns hydrogen stored at 350 bar without the need for a fuel cell stack. It uses two hydrogen injectors in each of the engine’s rotor housings to directly inject hydrogen into the intake chambers. Because rotary engines do not have pistons they tend to operate with less noise.

Energy output in the Renesis engine reaches 154 kW with gasoline, and 80 kW with the less energy-dense hydrogen. Mazda says the new Premecy powertrain improves output by 40 percent, but isn’t yet supplying specifications.

Operating on hydrogen fuel alone, the Premacy has a 124-mile range, or about double that of the RX-8’s hydrogen range. The Premacy is engineered with a transversely mounted rotary engine versus a longitudinal layout on the previous generation. Under the new configuration, Mazda notes its intake/exhaust resistance and combustion efficiency are improved for heightened output at a variety of engine speeds. The vehicle provides seating for five adults along with more luggage space compared with the two-door RX-8.

Mazda says it’s ready to begin leasing model a year from now in Japan, but doesn’t reveal pricing or if it will be available to consumers. Mazda leased its eighth rotary gasoline/hydrogen engine model in the RX-8 RE to Japan’s Ministry of Economy, Trade and Industry in August. That monthly lease price with tax comes to 420,000 yen or $3,500 US.

Mazda, a champion of the rotary engine since the 1970s, first began road testing on the gas/hydrogen powertrain back in 2004. Two years later, Mazda received the green light from Japan’s Ministry of Land Infrastructure and Transport to begin leasing the rotary engine vehicles to government and private industry fleets.

OCTOBER 2007