Mazda RX-8 Hydrogen Rotary Engine Sports Car
By Todd Kaho
Deep in the heart of the vast Mazda Motor Corp. complex in Hiroshima, Japan – one of the largest automotive facilities in the world – Green Car recently had the opportunity to drive the landmark Mazda RX-8 Hydrogen RE. For those wondering, “RE” stands for Rotary Engine. While this developmental car is not new, over the past four years continuing development activities on the RX-8 Hydrogen RE have brought a level of refinement that now allows commercial corporate operation.
The RX-8 Hydrogen RE is a dual-fuel vehicle, so hydrogen refueling station convenience is not as critical, particularly for fleet uses where the vehicle regularly returns to a central location. Changing back and forth from gasoline to hydrogen is easy. At the press of a button, the car switches over from one to another. This flexibility allows the RX-8 to burn H2 around town and in areas where smog forming emissions are a problem. When running on H2, the RX-8 Hydrogen RE also achieves zero emissions of CO2. Out on the open road where more power is needed and hydrogen refueling options are limited, this RX-8 is perfectly happy to burn unleaded gasoline.
We found little in the way of operating differences between the two fuels while turning laps around Mazda’s Hiroshima test track. Other than our test car being right-hand drive, the RX-8 Hydrogen RE performs like a typical RX-8 when running on gasoline. The rotary engine’s power is smooth and acceleration brisk as the sporty four-seat coupe is toggled through its paces with the six-speed automatic’s steering wheel-mounted paddle shifters. The RX-8, like the RX-7 that preceded it, has always been a kick to drive, and the Hydrogen RE is no exception. Handling is quick and responsive thanks to a well tuned chassis.
With one test lap complete, the blue H2 button to the right of the steering wheel was pushed and held for a few seconds to effect a fuel changeover. The transition between gasoline and hydrogen is uneventful with just a slight hesitation during the process. Changing fuel sources can be done on the fly so there is no need to stop the vehicle. The driver simply holds the button in for a few seconds and the engine management computer handles everything else. When operating on hydrogen, a decrease in power – particularly torque – is noticeable. Though acceleration is slower on hydrogen, there is adequate power for around-town driving and to maintain a steady cruise once at speed. With zero CO2 emissions, the ability to power the RX-8 with hydrogen is a significant achievement.
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