Mazda5 gas/hydrogen hybrid
Mazda5 gas/hydrogen hybrid. Click image to enlarge

Story and photos by Norm Mort

Photo Gallery: Mazda5 gas/hydrogen hybrid

Tokyo, Japan – Mazda’s “Zoom-zoom” slogan began as a North American advertising theme back in 1999, but it wasn’t long (2002) until the entire corporation adopted the concept. “Zoom-zoom” helped promote the “fun to drive” feeling Mazda was trying to relate to its customers.

Said Mazda General Manager and Executive Officer Hirotaka Kanazawa in a pre-show presentation: “We have grown the Zoom-Zoom tree big and strong along with its three main branches: the themes of Stylish, Insightful and Spirited. Today, Mazda is concentrating on cultivating the branches of “environmental protection” and “safety” as we work to extend the tree’s powerful roots even deeper into the soil and make it grow even larger.”

Mazda’s determination and passion is expressed in the “Sustainable Zoom-Zoom” long-term technology development plan that was announced in spring, 2007. That new development plan includes the ultimate production of a hydrogen fuel cell rotary engine, but in the meantime work will focus on further developing the hydrogen/gas hybrid version of the rotary engine.

The company feels hydrogen offers the best solution to both environmental issues and the reduction of use of the earth’s limited resources. Currently under development is a hydrogen fuel cell rotary engine. Initial impressive results include a 400-km range and power comparable to a 3.0-litre V6.

Mazda5 gas/hydrogen hybrid
Mazda5 gas/hydrogen hybrid. Click image to enlarge

On display at the Tokyo Motor Show were a variety of development projects geared toward that realization. This included a new hydrogen/gas hybrid rotary-powered car in the form of a Premacy (Mazda5). Already in limited production; eight built since 2006, the hydrogen rotary/gas hybrid RX8 RE models are being tested by seven companies and government agencies in Japan.

About the same number of Premacy (Mazda5) hydrogen/gas hybrids will be delivered for leasing in 2008. According to Mazda officials, these are real-world vehicles that can be ready for practical, wide-spread application once an adequate supporting infrastructure is in place – i.e. the building of additional hydrogen refueling stations.

The new Mazda Premacy Hydrogen RE Hybrid incorporates the dual-fuel system of the rotary RX8 Hydrogen RE, but is a further evolution in terms of practical use and driving performance.

The newest version of this hybrid powerplant has improved performance (0-100 km/h in 11 seconds verses 0-100 km/h in 18 seconds). Power output in this latest generation hybrid has increased by 40% compared to the RX-8 Hydrogen. It also features a 100% extended range between re-fueling from 100 km to 200 km; increased seating capacity for five adults and comes with greater luggage space.

The configuration of the hydrogen rotary engine has been changed from a longitudinal to a transverse layout and its intake/exhaust resistance and combustion efficiency are key factors in the improved yield in output across a wide range of engine speeds.

Mazda5 gas/hydrogen hybrid
Mazda5 gas/hydrogen hybrid. Click image to enlarge

In addition, a new concept hybrid system to match the latest hydrogen rotary engine was developed. The RX8 generation of the hydrogen/gas rotary engine had problems characterized by low torque and poor combustion efficiency in the low rev range. Mazda stated the new system overcomes both of these problems while also benefiting from an increased hydrogen capacity. Thanks to progress in electric drive technology, the system realizes a higher energy-efficiency and a quicker response for performance driving while providing lower fuel consumption. Mazda also noted that the acceleration kicks in the instant you hit the accelerator, creating a more dynamic feeling from the synchronized engine and motor power.

The new system sends power from the motor directly to a reduction gear rather than the previous electric motor transfer. Also, the newest hybrid system more efficiently converts energy from hydrogen combustion into electricity that powers the electric motor.

“The new synchronization of the engine and motor has created a kind of direct performance,” noted Program Manager Akihiro Kashiwagi. The result is vastly improved acceleration and overall performance. ”

It only seems fitting that on the 40th anniversary of the original rotary engine powered Cosmos sports car, Mazda is reconfirming its commitment to rotary engine development. The company seems determined to continue to put both its money and its faith in this powerplant.

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