Driving Sports

The silver lining of the current energy crisis is the movement by automakers to fund new research and development into alternative fuels. And what's even more heartening is that different automakers are chasing different technologies in an effort to find the workable replacement for fossil fuels and a meaningful reduction in polluting emissions.

Some are focused on diesel engines – by spraying carbolic acid into the exhaust stream, a modern diesel engine can reduce its greenhouse gas emissions by a third and its particulate emissions by 98%. Those diesels can also run on biofuels, further reducing pollution and dependence on fossil fuels. Some automakers are researching plug-in hybrids, EVs, and alcohol-based flex-fuels. Several automakers have invested in hydrogen research. Among those, including GM, Toyota, and others, the usual focus is on hydrogen fuel cells as generators of electricy.

But Mazda has taken a different path. Instead of using a fuel cell to generate electricity, Mazda's designs "burn" the hydrogen directly in an internal combustion engine to produce kinetic energy. The emissions are the same – just pure water – but the different approach offers some interesting possibilities for range and flexibility.

Because Mazda is burning the hydrogen in its existing rotary engines, the Mazda hybrids can switch from hydrogen to gasoline operation at any time, increasing the car's range and the ability to use whatever fuel is available.

Mazda brought two examples of their work to Monterey, California this week for testing. I was lucky enough to be invited down to test-drive both vehicles.

The first hydrogen prototype is a modified version of Mazda's popular RX-8 sports car, modified to run on both hydrogen and gasoline fuels. The car simply burns hydrogen in its engine to provide power, and allows the driver to switch between the hydrogen and gasoline fuel tanks. The car has about a 60 mile range on a tank of pure H2, at which point the car will switch to gasoline. Apart from a slight dip in horsepower, there's no noticeable difference between driving on hydrogen and gasoline.

The second vehicle is a modified version of the Mazda5 minivan-like passenger car. This vehicle uses a series hybrid drivetrain – meaning that the internal combustion engine is used only to recharge the batteries or directly generate electricity to run the electric drive motor. The internal combustion engine is again Mazda's proven rotary design modified to run on hydrogen or on gasoline. Like the RX-8, this vehicle can travel up to 60 miles using its onboard hydrogen supply before switching to gasoline.

The driving experience in the Mazda5 was more like a conventional hybrid such as the Toyota Prius or Honda Insight. The car is silent on takeoff and kicks on the hydrogen engine only as needed to generate electricity.

Alternative fuel naysayers will be quick to point out that hydrogen is not an energy source, but rather a storage medium for energy, and that it takes more energy to create a tank of hydrogen than we can currently get back out of the gas. The Japanese engineers who presented these cars acknowledged those truths readily. The point of this work is to more completely understand the engineering ramifications of alternative fuels and the many different options for direct combustion and hybridized powerplants available.

These vehicles are not yet ready for sale in the United States, but Mazda has been leasing them in Japan, where hydrogen stations are being built, and Mazda will participate in the "Hy-Nor" program in Norway this year as development continues.

In the modern era, the only unforgivable action for an automaker is to do nothing. Mazda's research into hydrogen combustion may not prove to be the magic bullet that solves the world's energy and climate problems, but they certainly deserve our applause and support for their work.

For more info: You can find out more about hybrid engines here, and check out Mazda's environmental page here.