Electric vehicles, hybrids and plug-in hybrids accounted for 3.2% of all cars sold in the UK in the first half of this year. Hydrogen fuel cell vehicles, however, make up only a fraction of that figure, although with models such as the Toyota Mirai and Hyundai ix35 Fuel Cell blazing a trail, there is an emerging market.
More than two decades ago, Chrysler developed a novel take on fuel cell power. The project started in 1993, when then US president Bill Clinton challenged Detroit’s big three car companies – Ford, General Motors and Chrysler – to develop a low-emissions car capable of 80mpg and have it on sale by 2003. The programme was known as the Partnership for a New Generation of Vehicle (PNGV).
Chrysler showed how it planned to meet the economy target at the 1997 Detroit motor show, where it revealed a petrol-hydrogen fuel cell system which it hoped to apply to a mid-sized saloon by 1999. This clever new take on the fuel cell system circumvented the need to wait for an infrastructure of hydrogen filling stations to develop.
“Instead of waiting 30 or 40 years until we have hydrogen filling stations on every corner, couldn’t one squeeze hydrogen from petrol now and run a fuel cell on the extract?” wrote Autocar’s Michael Scarlett after examining Chrysler’s system in Detroit. “That would get the clean, efficient fuel cell going much sooner. Chrysler believes such a car could be quieter, much more efficient, just as quick and practically a zero polluter. What’s more, it could be on the market within 10 years.”
The system worked by pumping petrol into a fuel vaporiser and burning a very lean mixture of fuel and air in order to turn the liquid into vapour.
“The vapour is then fed to the partial oxidation reactor, which is basically a metal can with a spark plug,” explained Scarlett. “The vapour is mixed with a small quantity of air and ignited. Partial combustion produces hydrogen and carbon monoxide.
“Carbon monoxide cannot be permitted to enter the fuel cell, so it is removed using a process which uses steam and a catalyst to convert most of it to extra hydrogen and carbon dioxide. The hydrogen is then mixed with air, then pressurised and flowed through a 5ft-long stack of fuel cells.”
As project leader Christopher BorroniBird explained to Autocar back in 1997: “The idea is to generate hydrogen without any impurities harmful to the fuel cell. With today’s engines you have to treat the gas in the exhaust; here we’re treating the fuel before it goes into the engine. In a sense the fuel cell is an emission control device.”
Borroni-Bird also explained that Chrysler’s pragmatic new fuel cell system wasn’t limited to petrol conversion. “The processor will burn anything: gasoline, diesel, methane or alcohol,” he said. “But it is still very much on the drawing board.”
Chrysler’s engineers believed that this unorthodox petrol-fed hydrogen fuel cell vehicle could, if fully developed, produce up to 50% better fuel efficiency than contemporary petrol engines. They also predicted a similar range to petrol cars, along with a 0-60mph time of less than seven seconds.
Despite a raft of publicity for this concept and other fuel cell projects during the 1990s, hydrogen has taken another two decades to reach our public roads in any significant way.