Toyota has tried to put hydrogen fuel cells in everything from passenger cars to buses and semi trucks, but now the automaker is embarking on a very different hydrogen-propulsion project.

Instead of fuel cells, Toyota is developing a combustion engine that runs on hydrogen, and not for road use. This time, it's for racing.

The automaker announced Thursday that it's developing a hydrogen-powered engine for use in a 24-hour race at Japan's Fuji Speedway, scheduled for May 21-23. The race is part of the Japanese Super Taikyu Series, which uses cars based on production models.

Super Taikyu Series racing

Super Taikyu Series racing

The 1.6-liter turbocharged inline-3 engine will power a modified Toyota Corolla Sport, running on compressed hydrogen gas rather than liquid gasoline. Internal-combustion engines are capable of running on gaseous hydrogen with some modifications, and Toyota even claims hydrogen combustion occurs at a faster rate—improving responsiveness.

The idea isn't new, but most automakers have intentionally avoided such an endeavor—partly to avoid being pressed to make the efficiency, carbon footprint, and emissions calculations for such a scenario. In the early 2000s, BMW briefly offered a hydrogen-powered version of its 7-Series luxury sedan, but for the most part automotive uses of hydrogen have focused on fuel cells, which produce electricity to run electric motors. Even BMW has shifted focus to fuel cells, and is in fact partnering with Toyota on development.

Similarly, use of hydrogen in motorsports hasn't really been explored. One team is planning to run an experimental fuel-cell car at the prestigious 24 Hours of Le Mans in 2024, but racing series are primarily focused on hybrid and battery-electric powertrains as a way to reduce emissions.

However, a hydrogen racing engine is in keeping with the automaker's ambitious hydrogen plans.

Toyota has been striving to build a hydrogen economy, for everything from industrial uses to high-profile uses like lunar rovers. It also just signed a strategic partnership with Chevron to further that goal, encompassing infrastructure development and research related to hydrogen transportation and storage.

The automaker has demonstrated its fuel-cell tech in small-loop freight hauling, and has developed a fuel-cell module to power future trucks and buses. However, Toyota has often conveniently avoided considering how most hydrogen is supplied—and the environmental implications of that supply chain.

As for Toyota's sole fuel-cell production car, we think the Mirai is the best, or one of the best, sedans that Toyota currently makes.