Toyota revealed prototypes of internal combustion engines capable of running on hydrogen, along with gasoline and other fuels, seeking to popularize alternate technologies to reduce carbon emissions.

The world’s biggest carmaker, alongside Mazda and Subaru, said they’re making progress on developing smaller, more efficient engines that can work with electric vehicle manufacturing platforms and capable of meeting strict emission regulations in the future.

Emboldened by robust hybrid-car sales, Toyota and its partners say fuel-burning engines have a role to play even as the industry shifts to battery EVs in a global push to decarbonize. The Japanese manufacturers have long been criticized for hesitating to fully embrace electrification, while BYD and Tesla take the lead in battery-based EVs.