The following text and illustrations are taken from Mazda's Environmental Presentation on Hydrogen Cars brochure that was included in a press kit distributed at the Earth Week celebrations in Toronto in 1994, with the added bonus of links to other web sites.

From a Carbon world to a hydrogen world. Now the earth is moving toward the era of clean energy.

Until now, our civilization had been developing on the basis of burning carbon-containing fuel, such as oil, etc. However, we, the members of modern society, are now faced with important tasks: one is to restrain CO2 emissions, responsible for the greenhouse effect, and the other is to prepare for the exhaustion of the earth's reserves of oil, our convenient fossil fuel. It is feared that extreme difficulty is involved in achieving these tasks because they are deeply related to modern individual society, and our lifestyle itself, which greatly depends on oil.

Hydrogen, chemical symbol: H. This element, abundant everywhere on the earth, is earning high expectations as a new energy resource. Hydrogen does not produce CO2 after combustion, it just creates water. Hydrogen is called a source of renewable energy, since it can be reversely extracted from water by electrolysis. We want to run a car on hydrogen, an idea now attracting the world's attention. In order to build a better relationship between cards and the environment, Mazda will continue to propose the possibility of a new-energy soceity through the development of hydrogen-fueled cars.

Concept of Hydrogen as a more common energy resource.

It is a well-known fact that hydrogen makes an excellent fuel, commonly used in rockets. However, we rarely find hydrogen being used as a fuel in ordinary situations. This is because we think enough energy needed for the present society is supplied by easy-to-use energy such as oil. However, in the future world of hydrogen energy, hydrogen will be used not only as a fuel, but also to construct a clean, compound energy system (Figure) by means of a mutual conversion with electricity. In order to achieve that, however, it becomes necessary to mass-produce hydrogen at low cost and to establish social bases for its full application.

Currently, the Japanese MITI (Ministry of International Trade and Industry) is planning to establish an international tranport and utilization system of hydrogen energy under the WE NET project. Also, Canada and Germany are carrying out projects to produce and utilize hydrogen. We are convinced that such efforst will develop into the themes of daily life. In the case of automobiles, for example, it would be necessary to establish a network system for easy supply and sites (fuel stands) for hydrogen.

Mazda's proposal to send hydrogen cars out into the world

Mazda has been focusing on hydrogen as the clean fuel of future generations for a long time. Having been actively conducting studies on the practicality of hydrogen cars, we have now reached the stage of developing highly practical vehicles with a hydrogen-fuel engine. Abnormal combustion can easily occur in a reciprocating engine, since hydrogen is highly combustible. Since a rotary engine, on the contrary, has a separate low-temperature air-intake chamber and high-temperature combustion chamber, excellent combustion can be obtained without causing the so-called backfire phenomenon, where ignition occurs in the hydrogen-intake process.

Another key factor was a fuel tank which realized safe storage (Figure) of hydrogen by applying metal hydride(Figure) (MH). Based on these two key factors, Mazda has been developing hydrogen-powered cars that can match the performance and range of conventional gasoline engine cars. As a result of this development, we exhibited our very first concept, the HR-X, at the Tokyo Motor Show in 1991.

Let's run our new dream. The birth of the hydrogen rotary engine car HR-X2

Building on the experience of our first-generation concept car, Mazda has now given birth to HR-X2, with further improved overall performance. HR-X2 is provided with various environmental considerations: a vehicle structure easy to recycle, application of new technology that makes more recycling possible, etc. This is a new concept car aiming at good harmony between the environment and energy while not forgetting the pleasure of driving. The newly developed hydrogen rotary engine (Illustration) yields 130 ps maximum power and a 17 kg-m maximum torque, with performance improved by expanding displacement and applying a method for hydrogen intake from a peripheral port. As to its practicability, we have newly adopted a cell-type storing alloys tank (Illustration) with improved safety and it is more suited for loading on a car, as well as for mass production. By searching for and closely selecting lightweight allows with high occlusion capacity, and improving the heat-exchange system, we have achieved a hydrogen-occlusion capacity of 43 Mn3 yieldig a range of 230km.

Running through the 21st century with clean energy

Strong, safe, and comfortable driving with longer range. Our task involved in putting hydrogen cars into practical use involves how close we can make them come to gasoline cars, in terms of performance and function. It is not easy to instantly overcome 100 years of automobile history, where drivers are spoiled by the thrill of acceleration, the pleasure of high-speed cruising, etc. Mazda has been continously carrying out experiments and resarches on hydrogen cars, e.g. the 626 Cargo and the MX-5, which are the trial cars based on mass produced models. By achieving our future technical tasks such as improvement of hydrogen engines and reduction of the weight and volume of the metal hydride, we wish to make the upcoming 21st century clean and green. Expectations for hydrogen cars running in harmony with a beautiful new urban space and environment are getting higher and higher.