Toyota is doing everything in its power to remain competitive in its pursuit of carbon neutrality, and has lined up an upgraded hydrogen-powered GR Corolla to compete in the Super Taikyu Fuji SUPER TEC 24 Hour Race. This engine has a custom-shaped tank that extends its cruising range and a liquid hydrogen pump that has improved durability, making it a noteworthy engine on the circuit. The model, tagged #32 ORC ROOKIE GR Corolla H2 Concept, is powered by liquid hydrogen, and the system still has some bugs to work out, so Toyota will definitely gain insight from its performance on the track. I would hope so.
Hydrogen-fueled GR Corolla for the Fuji Super TEC 24 Hour Race
The engine that Toyota installed in the #32 ORC ROOKIE GR Corolla H2 Concept has several features that make it a noteworthy engine in the hydrogen class.
Improved durability of hydrogen pump
A liquid hydrogen pump is a component that increases the pressure of liquid hydrogen fuel before it is injected into the engine. Toyota has put a lot of effort into improving this so that it can complete the race without having to replace it. At the last Fuji Super TEC, Toyota experienced three of these.
When moving hydrogen from the tank to the engine, the pump uses piston motion to reciprocate. It generates higher pressure than normal pumps, making the rotational movement of shafts and gears smoother. However, previous engines had uneven loads and parts wore out quickly.
To get around this, Toyota installed a dual-drive crankshaft mechanism. Adjusting torque application provides a more balanced boost piston action, greatly increasing durability.
For the 2023 Fuji 24 Hour Race, Toyota used three pumps with an average durability of 8 hours. By 2024, we want to eliminate alternatives and achieve durability of more than 24 hours.
Custom-shaped tanks, increased range
The design of Fuji Super TEC’s new liquid hydrogen tank is oval-shaped compared to the cylindrical shape of the previous version. This makes more efficient use of space, doubles the amount of hydrogen on board and increases range. Cylindrical tanks are suitable for gaseous hydrogen because they provide better pressure distribution. However, liquid hydrogen has a lower pressure, so tanks can be customized to prioritize other performance factors.
CO₂ automatic recovery technology
The capture process involves sucking CO₂ out of the atmosphere through a large intake of air, facilitated by the heat released by internal combustion. The CO2 is then captured by an absorber. The 2024 Fuji Super Tech will be equipped with a mechanism that automatically performs the adsorption and separation processes by rotating the filter while driving, eliminating the need for mechanics to manually switch between adsorption and separation processes.
Here is a comparison of race specs from 2022 to 2024:
2022 race Fuji 24 Hours race 2023 final race 2024 target Fuel type Gaseous hydrogen (compressed 70MPa) Liquid hydrogen Tank capacity 180 liters (gas) 150 liters 220 liters Hydrogen amount 7.3 kg (gas) 10 kilograms 15 kilograms Number of laps 12 Lap (approx. 20 laps (approx.) 30 laps (approx.) Cruising distance 54km (approx.) 90km (approx.) 135km (approx.)
Advantages of liquid hydrogen
Liquid hydrogen has two main advantages over the compressed gas form typically used in FCEVs (hydrogen fuel cell electric vehicles):
One of the properties of liquid hydrogen is that it has a higher energy density than compressed gas, so it can deliver about 50% more energy from the same volume. Liquid hydrogen can be stored at normal pressure, so there is no need for high-pressure storage tanks.
Complications of liquid hydrogen engines
Engines running on liquid hydrogen have some serious issues, and unfortunately for car companies looking in this direction rather than EVs, solving them won’t be easy. Most of this has to do with the fact that liquid nitrogen has to be kept very cold (below -253°C) so that it doesn’t evaporate.
Hydrogen fuel pumps wear out very quickly, reducing the efficiency of the system. Petroleum lubricants cannot be used as they can contaminate the fuel. Sealing of pump components is also an issue, as it is difficult to maintain a tight seal at extremely low temperatures. Even though liquid hydrogen has a higher energy density than gas, hydrogen-burning vehicles require large fuel tanks to achieve an acceptable range. Compared to electric cars, hydrogen is burned less efficiently compared to the amount of electricity required to charge the battery. The combustion efficiency of hydrogen is typically 20% to 40%, while the combustion efficiency of electricity is approximately 77%.
Despite evidence showing that electricity is the way to go in the fight against carbon emissions, Toyota remains confident that hydrogen engine development will bear fruit.
