Toyota entered the recent Eneos Super Taikyu Series 2024 with the #32 Orc Rookie GR Corolla H2 Concept, a hydrogen-powered GR Corolla running on liquid hydrogen.
At the same event it exhibited a concept model that envisions the use of boil-off gas generated while driving.
Liquid hydrogen has a higher density than gaseous hydrogen. This allows for more hydrogen to be stored in a tank but presents an issue with boil-off. This is a problem for all liquid hydrogen systems, where the liquid hydrogen fuel in the tank evaporates due to natural heat that enters from outside. Until now, the boil-off gas (vaporised hydrogen) generated in the fuel tank while driving has been released into the atmosphere without being used.
Although Toyota’s vehicle is still in the concept stage, this technology is expected to improve the energy efficiency of the entire liquid hydrogen system by recovering and using boil-off gas as energy. Toyota is now looking to form partnerships that will help make this technology a reality.
The technology would produce reusable fuel by sending any boil-off gas released to a self-pressuriser (a device that increases pressure without relying on external energy). Boil-off gas can be converted back to usable hydrogen fuel for the engine by applying pressure, but increasing the pressure sufficiently usually requires energy such as electricity. The self-pressuriser uses the pressure of the boil-off gas to increase pressure by two to four times and produces reusable fuel without using any additional energy.
