Bodystyle, dimensions and technical details

Hydrogen fuel cell cars aren’t all that rare in experimental form. Almost every car maker worth its salt has built one during the past couple of decades.

What has prevented them from progressing past the prototype stage is principally the cost of the precious metal (typically platinum) required for the fuel cell, the cost and challenge of storing enough hydrogen in the car to run the fuel cell, the limited availability of hydrogen and concerns about the robustness of unproven technology.

Unlike earlier fuel cell prototypes that ran on liquefied hydrogen, the Mirai doesn’t suffer from boil-off

Toyota is coy about the cost of the Mirai’s 114kW polymer electrolyte fuel cell, but it arrives at a time when the technology has become vastly more affordable, plummeting from hundreds of dollars per kilowatt of generating capacity required to just tens.

The Mirai’s fuel cell is about the size of a conventional petrol tank and sits under the front seats. In durability trials, it is claimed to have powered the car to more than 60,000 miles in less than six months without any hiccups and cold-started in temperatures as low as -30deg C.

In the engine bay is a 152bhp electric motor, borrowed from a Camry hybrid and driving the front wheels via single-speed gearing. Behind it are two high-pressure hydrogen tanks (one for storage, one for expansion) and a high-voltage nickel-metal hydride drive battery, in order that the Mirai can regenerate and store energy under braking like any other Toyota hybrid.

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The company took the chance to reference its corporate history (before it built cars, Toyota manufactured looms) and developed its own woven carbonfibre hydrogen tanks for the Mirai.

Although rated for 700bar, they can contain almost twice that, making them as crash-safe as possible. Gas storage capacity is five kilograms, and it turns out that a Mirai will do roughly as many miles on a kilo of compressed hydrogen as a modern petrol-fuelled hybrid will do on a gallon of unleaded.

Challenging looks aside, it is otherwise quite conventional. As a four-door saloon about the size of a Toyota Avensis or a Ford Mondeo, it’s suspended by MacPherson struts up front and a torsion beam at the rear.

And weighing more than 1.8 tonnes with all that advanced powertrain technology on board, it is approaching the limit of what a beam axle can be expected to suspend without any compromise to either ride or handling – or both.