At the end of April 2021, Toyota announced it would be testing the performance of a new hydrogen-fuelled internal combustion engine by installing it in a racecar that would compete in one of Japan’s toughest motorsports events: The NAPAC Fuji Super TEC 24 Hours.

The engine was developed as part of Toyota’s progress towards realising a carbon-neutral mobility society and powers a Corolla Sport built to technical regulations for the Super Taikuyu endurance racing series. Entered by ORC ROOKIE Racing, the car made its race debut on the 21-23 May 2021 race weekend. 

Hydrogen-powered Toyota Corolla during The NAPAC Fuji Super TEC 24 Hours. Photo: Masahide Kamio

 

Development 

Unlike Fuel Cell Electric Vehicles (FCEVs), which produce electricity to power the engine through a chemical reaction between hydrogen and oxygen in the air, Toyota’s hydrogen engine generates power through combustion, using fuel supply and injection systems modified from those used in a petrol engine. 

Toyota’s G16E-GTS, 1,618cc turbocharged three-cylinder engine fuelled by hydrogen. Photo: Toyota

 

Toyota believes that attaining carbon neutrality will require utilising and improving current technologies – hence this strategy. To that end, it sought to make the conversion from a petrol-fuelled internal combustion engine with minimal component changes and control technologies. Initially, the company tried a bi-fuel approach, using 50% gasoline and 50% hydrogen. From there, it attempted 100% hydrogen. The first engine broke down within five minutes, but with calibration sorted, the team was confident they could take it to an endurance racing environment for the ultimate test. 

Hydrogen-powered G16E-GTS race engine installed in Corolla Sport racecar during the test. Photo: Noriaki Mitsuhashi/N-RAK PHOTO AGENCY

 

The race engine is the same G16E-GTS, 1,618cc turbocharged three-cylinder unit found in the Yaris GR, which features technologies that Toyota has refined in its motorsport participation and production vehicles; Only this time it’s using compressed hydrogen fuel. As hydrogen combustion happens faster than petrol combustion, it provides the potential for a highly responsive race engine. 

Toyota G16E-GTS, 1,618cc turbocharged three-cylinder engine and driveline as it appears in the Yaris GR. Photo: Toyota

 

One of the team’s main challenges was developing an injection system capable of handling hydrogen while also achieving stable and efficient combustion. Here, the expertise of long-term supplier Denso was called upon to establish the injectors. 

Given hydrogen burns seven times faster than regular gasoline, it puts significantly more peak strain on the engine’s components. As a safety measure, the G16E-GTS race engine output was adapted for the hydrogen fuel by reducing power down from the 261 BHP of the road going machine. 

Toyota harnessed the fuel tank technology from its Mira FCEV (fuel cell electric vehicle) to ensure safe hydrogen fuel storage under racing conditions. To this end, the Corolla race car features four hydrogen tanks mounted within the cabin – two standard medium tanks and two shortened ones, giving a combined fuel capacity of 180 litres.

Hydrogen tanks installed in the hydrogen-powered Corolla racecar. Photo: Noriaki Mitsuhashi/N-RAK PHOTO AGENCY

 

The duty cycle of the hydrogen-fuelled internal combustion engine compared with a fuel cell also had to be accounted for, with the former emptying the hydrogen tanks much faster due to sustained full-throttle running. Toyota noted that though the Mirai tanks had been thoroughly tested in challenging road running, racing in a 24-hour event was uncharted territory.

The tanks were subject to additional strength tests to ensure they were fit for competition use. When installed in the race car, composite plates surround them to provide further protection. The downside of the required high storage volume is rear visibility for the drivers, a problem circumvented by using a rear-view camera.

Refuelling test before the race event. Photo: Noriaki Mitsuhashi/N-RAK PHOTO AGENCY

 

Fukushima Hydrogen Energy Research Field in Namie Town, Japan, supplied Toyota hydrogen for the event. A special refuelling zone was set up in the paddock outside of the pitlane, with two large trucks and a series of tanks supplying the compressed hydrogen needed for the car to complete the race distance.

 

Hydrogen fuelling station set up for the Corolla Sport for the 24hour event. Photo: Noriaki Mitsuhashi/N-RAK PHOTO AGENCY

 

Debut Performance

The hydrogen-powered Rookie Racing-entered Corolla was entered in the ST-Q class and completed 358 laps in the Super Taikyu blue riband 24-hour race at an average speed of 67.963km/h – representing approximately 50% pace of the race-winning car.

The team carried out 35 pitstops over the course of the race, which took around seven minutes each giving an average stint length of 10.2 laps. As such, the car spent approximately four hours refuelling. Its fastest lap of 2m04.059s was slightly quicker than the best lap set in the slowest ST-5 class (for modified production cars with a displacement of 1,500cc or less) and around 24 seconds slower than the outright fastest lap.

Hydrogen-powered Toyota Corolla during The NAPAC Fuji Super TEC 24 Hours. Photo: Masahide Kamio

 

From Toyota’s perspective, the hydrogen-fuelled Corolla’s debut was a success, and the project will accelerate the development of hydrogen cars and play a role in helping societies reduce their carbon emissions alongside electric vehicles. Toyota sees it as strengthening its efforts towards achieving carbon neutrality by promoting hydrogen in FCEVs and other products. Its use of motorsport further refines its hydrogen engine technologies supporting its aim of realising a hydrogen-based society future.

Hydrogen fuelling systems could be a thing of the race paddock in the future. Photo: Noriaki Mitsuhashi/N-RAK PHOTO AGENCY