Pressing the red “Start” button, the Mazda RX-8 fires up, the pint-sized rotary engine under its hood buzzing as I modulate the throttle, shift into gear and launch down the test track at Mazda’s
Acceleration is a little slower than I’m used to, but that’s the trade-off signaled by the glowing “H2” light on the sports car’s instrument panel. This prototype version of the rotary-powered RX-8 has been converted to run on hydrogen, the lightweight gas that many experts believe will be the fuel of the future.
Like most of its competitors, Mazda has come to recognize the long-term need to find alternatives to conventional gasoline. And like the rest of the industry, it is toying with a variety of options, including both electric and gasoline-electric hybrid vehicles. But the Japanese maker is placing its big bet on hydrogen, a fuel it has been tinkering with for two decades, in a series of prototypes and now, in a small fleet of vehicles, like this RX-8, undergoing real-world testing.
The challenge, says technology chief Hirotaka Kanazawa, is to replicate the sort of sporty, fun-to-drive feel that characterizes Mazda products using environmentally-friendly powertrain technology, “Sustainable Zoom-Zoom,” the automaker calls it, in a nod to its global advertising slogan.
With its relatively limited resources, making the switch to alternative power could be a challenge for a manufacturer the size of Mazda. It does, of course, help to have a partner like the
“Without the synergies (of working with) Ford,” acknowledges
While most experts believe fuel cells are the long-term answer, there are some near-term advantages to powering conventional IC engines with hydrogen. For one thing, it allows the use of existing powertrains with only minor modifications. And they can be converted to bi-fuel operation. With the touch of a button, the RX-8 I drove in
“We need to develop multiple solutions to address this multifaceted problem,” Mazda’s chief technology officer adds.
The rotary engine is particularly well-suited for using hydrogen, Mazda engineers contend. The rotary runs cooler than a piston engine, for one thing, and that reduces the amount of smog-causing NOx, or oxides of nitrogen, produced as an inadvertent byproduct of combustion.
Mazda currently has eight bi-fuel RX-8s in real-world operation. Meanwhile, it’s about to roll out a new test platform that could prove even more effective in using hydrogen power, dubbed the Premacy HRE Hybrid. The HRE is short for hydrogen rotary engine, but this particular version of the maker’s Japanese-market crossover vehicle adds a serial hybrid to the powertrain package.
The current crop of hybrids, such as the Toyota Prius, Ford Escape Hybrid, and Honda Civic Hybrid, are parallel systems. In other words, they primarily drive their wheels using gasoline power. Their batteries adds an extra bit of boost for faster acceleration, while some, such as the Prius and Escape, also can run solely on electric power for short bursts.
The Premacy HRE, however, used its hydrogen-fueled rotary engine solely as a generator, producing electricity that can either be stored in its lithium-ion battery pack, or piped directly to the motors turning its wheels. The system is notably more efficient, one reason the bigger Premacy doubles the range of the RX-8, getting up to 200 kilometers (125 miles) on hydrogen alone.
While Mazda plans to begin field-testing the Premacy HRE Hybrid in the coming months, the automaker is far more skeptical than some of its competitors about the speed with which hydrogen power will take over for gasoline. While it won’t disclose specific production plans, it is looking at no earlier than 2020 to introduce a truly competitive, next-generation rotary, capable of 250-mile range on hydrogen.
And in the nearer term? As we get out of the hydrogen RX-8, we’re handed the keys to another Mazda prototype, the one featuring its Smart Idle Stop System, or SISS. This “mild hybrid” system is similar to some others now on the road, which are capable of briefly stopping their engines at a stop light, in order to save fuel. But existing systems, such as the one in the Saturn Vue Green Line, require using the starter motor to kick-start the engine when the light changes and the driver steps on the throttle.
Mazda’s SISS uses the engine itself, a process it claims is quicker and smoother to restart. A brief run behind the wheel suggests they’re at least half right. The SISS system restarts instantaneously, eliminating the annoying hesitation of existing hybrids. It’s still a bit rough, though that’s not surprising in an early prototype.
The SISS technology is currently being tested on a 2.0-liter four-cylinder engine, currently used only in the Japanese domestic market, but Mazda officials say the system is “scalable” and as they work out the bugs, it should become available for larger engines exported to other markets.
What’s clear is that Mazda has to move quickly. The push for alternative power is only accelerating, driven by both rising fuel prices and mounting concerns about global warming. Without a way to deliver Zoom-Zoom using sustainable alternatives, Mazda would likely find itself in a serious bind.
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2007 Tokyo Motor Show Coverage by TCC Team (10/24/2007)
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2007 Mazda Premacy HRE Concept by TCC Team (10/24/2007)
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