Toyota has released details of the latest updates to its hydrogen-fueled ICE Corolla race car, ahead of its entry into the Super Taikyu series 24-hour race at Fuji, May 24-26.
In 2023, the company started to refine a liquid hydrogen fuel system for the car, and this has been one of the main areas of refinement this year. For example, the fuel pump, which must operate a very low temperatures, proved challenging from a reliability perspective and during the 2023 race had to be changed twice; a very time-consuming process.
Hydrogen fuel pump refinement
According to Toyota, the Corolla uses a reciprocating pump. Because of the high pressure this pump generates, the bearings for the shaft and gears on one side of the crank, which transfers torque to the motor by converting reciprocating motion into rotational motion, were unevenly loaded, causing them to wear out and degrade quickly.
A new, dual-drive crank mechanism has been implemented to improve the pump’s durability. The application of motor torque from both ends of the crank enables the boosting piston to move in a well-balanced manner, thereby significantly increasing pump durability.
Further changes to the Corolla have seen the liquid hydrogen tank changed from a cylinder to an oval shape. As a result, the tank has a capacity 1.5 times higher than that of the cylindrical tank. This doubles the hydrogen volume, and thus the cruising range, over the 70MPa compressed gaseous hydrogen tanks used until 2022.
Carbon capture technology
Toyota has also improved on a CO2 capture system fitted to the engine, not for the exhaust but for inlet air. This captures CO2 from the incoming charge and uses heat from the engine oil in the conversion process, with the separated CO2 stored in a small tank filled with an adsorbent. 
The system was used at the final Super Taikyu race in 2023, but mechanics had to manually switch the CO2 absorption and separation processes. However, for 2024, a mechanism has been implemented that automatically switches them by slowly rotating the CO2 absorption filter while driving.
