Revealed: BMW's secret i8 hydrogen sports car

BMW could have turned its high-tech i8 plug-in hybrid sports car into an even higher-tech hydrogen fuel-cell electric car.

In fact, BMW’s development engineers did, but it was kept as a secretive in-house development prototype, revealed only this week.

Built five years ago, the mule was built off the remains of the very first i8 prototype and had BMW’s then-latest generation of long, cylindrical hydrogen fuel tank inserted uncomfortably into its battery space.

BMW’s vice-president of powertrain research, Matthias Klietz, admitted the car ran to 100km/h in just six seconds, though it looked like it got there seconds faster.

“The i8 fuel-cell was done five years ago and then we used it for two or three years for testing and proving,” Klietz said, admitting the car predated BMW’s technical tie up on fuel cell development with industry powerhouse, Toyota.

When the board called and told the prototype engineers to go ahead with another generation of hydrogen fuel-cell mules, sources said the engineers preferred to scavenge the first i8 prototype instead of shoving the bulky technology into a large SUV or sedan.

“This was a very important development vehicle for us,” Klietz said.

“It was a pure prototype for the fuel cell, but it still had 180kW of power and did 200km/h.

“We wanted to show us, to convince us, and then convince the management that fuel cell vehicles could be sporting.

“We wouldn’t be BMW if our default position as engineers, when we’re given a free hand, isn’t to instinctively make it a sports car, would we?” he asked.

Even so, it failed to attract an official name, a codename or even a nickname from the BMW managers and test drivers.

One senior source admitted it could have been a turning point in the i8 development, too, and might have forced a switch from plug-in hybrid to fuel-cell electric power, but the technology was too immature and far too bulky.

While the fuel stacks themselves were not overly problematic, the cylindrical hydrogen fuel tank, which is pressured to 700 bar, was nearly three metres long and almost half a metre in diameter. Additionally, the mule’s control and power electronics occupy the entire rear seat area of the i8’s usual four-seat cabin.

It loses the entire rear luggage area, too, with the space dedicated to the i8’s three-cylinder turbocharged petrol engine not being large enough for the vertical fuel-cell power-generation stack.

“There were packaging limitations, of course, but the car had 700 bar of pressure, so it stored 4kg of hydrogen,” he said.

“That gave us 350km of range, too.

“We did it five years ago, very early in the i8’s development for industrialisation, and we used it for two or three years. It’s tired now.

“It was not a vehicle for long-range tests and all the components that were used for the fuel-cell system were all new developments that we made specifically for it.”

Even though insiders insist BMW is heading back to the Le Mans 24 Hour race with an experimental hydrogen fuel cell machine in 2018, it doesn’t believe the technology will drive the long-term future of sports cars.

“We believe fuel cells will be for people who do longer distances and it needs a larger vehicle for packaging,” a senior source said.

“It might get to sports cars at a later time, but it seems more of a natural fit for things like larger sedans and SUVs.”