UK Company to Introduce Hydrogen Fuel Cell Urban Car; Open Source Approach

Cutaway of the Hyrban. Ultracapacitor bank is beneath the seat. Click to enlarge.

UK-based Riversimple will unveil on Tuesday (16 June) its first production-intent car: a two seater hydrogen fuel cell urban car with composite bodyshell. Riversimple designed the Hyrban (earier post) to achieve 300 mpg (energy equivalent); the company calculates that the fuel cell car will have well-to-wheel CO₂ emissions of 31 g/km when fueled with hydrogen produced via steam methane reforming of natural gas.

The Hyrban has a top speed of 50 mph (80 km/h), can accelerate from 0 – 30 mph in 5.5 seconds, and has a range of more than 200 miles (320 km). Riversimple, founded by Hugo Spowers, a former motorsport engineer and racing driver, earlier initiated the hydrogen LIFECar project through its subsidiary OSCar Automotive Ltd. (earlier post).

Network electric powertrain. Click to enlarge.

Riversimple is establishing an open source foundation (The 40 Fires Foundation) to help advance the development of the vehicle.

The Hyrban implements what Riversimple calls a network electric powertrain—the different components of the car’s electrical system allow electricity to pass in multiple directions (eg. from the fuel cell to the motors or to the ultracapacitors, from the motors to and from the ultracapacitors, and so on). The powertrain includes

6 kW fuel cell (developed with Horizon Fuel Cell Technologies of Singapore).
21 kg of ultracapacitors, capable of absorbing more than 30 kW of power from regenerative braking, and of delivering 15 kW for bursts of acceleration of up to ten seconds, enough time to reach maximum cruising speed.
Four in-wheel motors

Almost all braking is done by the electric motors. This energy is then stored in the ultracapacitors bank which can provide 80% of the power required for acceleration. This, combined with the lightweighting, enables Riversimple to use a fuel cell with a fifth the power required in a conventional car.

Riversimple worked with Oxford and Cranfield University on the power electronics, motors and control system.

We don’t believe any one technology, whether batteries or fuel cells, can be as amazingly versatile as the internal combustion engine has been. We believe different types of vehicle will fill different niches, and it makes abundant sense to choose different power trains for different environments. Battery power will be more efficient over short distances but batteries are very heavy and we believe hydrogen fuel cell power will be superior over long ranges (150 miles+) and will emerge as the most efficient and flexible choice for inter-urban vehicles.

—Riversimple

Open source approach. Riversimple says it is licensing its designs to the independent open source foundation 40 Fires Foundation for two reasons:

Human society urgently needs more fuel efficient vehicles, and by sharing its ideas and designs, Riversimple hopes to encourage others to adopt the technology.
Riversimple thinks it is a sound business strategy for a small company trying to complete the major OEMs in one of the world’s largest industries.

Commercialization and manufacturing. Riversimple plans to lease its cars, not sell them; fueling will be included in the lease cost. The economies of scale of carbon composites frames are very different from those of steel-bodied vehicles, the company says, and anticipates that its vehicles are likely to be produced in small factories producing 5,000-10,000 vehicles per year, allowing for considerable local variation in the car.

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