Mazda HR-X

You're looking at a car that features at its core (yes, in the middle) a hydrogen-powered rotary engine. If I had to guess, I'd say this working prototype was based off of the then-upcoming Mazda AZ-1 or Suzuki Cara, albeit with a taller greenhouse and more futuristic styling.

Thanks to a digitized New York Times article from 1992, there's actually quite a bit of information online about this car. For starters, it's apparently capable of a top speed of 220 km/h (135 mph) — damn impressive for a first attempt at a new fuel.

Second, it was equipped with an interesting fuel tank / hydrogen stack, as the Times' Calvin Sims will explain: 

"The Mazda tank, which is six inches thick and located in the floor of the vehicle, contains a metallic compound that absorbs the compressed hydrogen during fueling and then releases hydrogen molecules when heated to power the vehicle."

Space-efficient, I like it. It held enough fuel for a 200 km (125 mile) jaunt, which would have made it an ideal urban runabout…in theory.

This prototype remains in Mazda's care, and apart from the sorta-production Mazda RX-8 Hydrogen RE and efforts from General Motors, Toyota, Hyundai, Honda, BMW and others, hydrogen technology has remained out of the hands of the general public. 

Having driven two hydrogen cars so far (a Honda FCX Clarity and BMW 7 Series), I can see the appeal of a smaller, more nimble take on a commuter car.

In an ideal world, would the HR-X be the MX-5 of commuter cars?