In a nutshell: Andy Green will return to Utah's Bonneville Salt Flats on Tuesday in a new kind of record car: one powered by hydrogen-burning engines. The Hydromax is a 32-foot vehicle powered by two hydrogen engines adapted from JCB construction machinery. Rather than using hydrogen in a fuel cell to make electricity, the engines mix pressurized hydrogen gas with air and ignite it. He could also pass the current hydrogen internal-combustion record of 185.5 mph and the electric-vehicle record of 341.3 mph. JCB has spent more than $134 million developing hydrogen engines.