A couple of weekends ago, when most of the world's motorsport attention was focused on Monaco and Indianapolis, Toyota President Akio "Morizo" Toyoda was taking part in the Super Taikyu Fuji 24 Hours at Fuji Speedway in Japan. Automotive executives racing their own products is not exactly unheard of, but few instances have been quite as unexpected as competing in endurance races with a hydrogen-burning Corolla.
A hydrogen-powered Toyota has shown up for the past few years, in fact, as the company uses the race track to learn new things about thermal efficiency that it says have benefitted its latest generation of internal-combustion engines, which it debuted to the public at the end of May.
With backing from its government, the Japanese auto industry has continued to explore hydrogen as an alternative vehicle energy source instead of liquid hydrocarbons or batteries. Commercially, that's been in the form of hydrogen fuel cells, although with very little success among drivers, even in areas that have some hydrogen fueling infrastructure.
But the hydrogen powertrain in the GR Corolla uses an internal combustion engine, not a fuel cell. The project first competed in the 24-hour race at Fuji in 2021, then again with a little more success in 2022.
For 2023, there was a significant change to the car, now fueled by liquid hydrogen, not gaseous. Instead of trying to fill tanks pressurized to 70 MPa (700 bar), now it just has to be cooled to minus-253° C (minus-423° F). Liquid hydrogen has almost twice the energy density—although still only a third as much as gasoline—and the logistics and equipment required to support cryogenic refueling at the racetrack were much less than with pressurized hydrogen.
The liquid hydrogen is stored in a double-walled tank that was much easier to package within the compact interior of the GR Corolla than the four pressurized cylinders it replaced. This year, the tank is 50 percent larger (storing 15 kg of hydrogen) and elliptical, which proved quite an interesting technical challenge for supplier Shinko. The new tank required Toyota to rebuild the car to repackage everything, taking the opportunity to cut 50 kg (110 lbs) of weight in the process.