The base vehicle for this race is a Corolla Sport, one step up in size from the GR Yaris that Morizo (aka Akio Toyoda) has been driving for ROOKIE Racing.

However, according to Toyota’s lead engineers on the project, Naoaki Ito and Naoyuki Sakamoto (chief engineer) of GR Project Operation Div., the race car is being fitted with the GR Yaris’s 4WD system. What’s more, they say that the engine has been converted from the GR Yaris.

Wait a moment ­– isn’t the engine hydrogen-powered? How could that have been ‘converted from the GR Yaris’? The engineers explained in more detail:

First was the technological innovation in injectors.

An injector is a device that sprays fuel into the engine. In gasoline engines, they inject liquid gasoline into the engine as minute particles.

For the new hydrogen-powered engine, however, the fuel is a gas. It took much effort to come up with technology that could inject this hydrogen in a way that ensures efficient and stable combustion.

The task of producing this technology has been promoted by a Toyota Group supplier, Denso, which has a long history of developing injectors. Denso’s engineers have been working on such technology since before the term ‘carbon neutrality’ became commonplace.

Ito expressed his gratitude for Denso’s efforts to date, saying ‘this is thanks to everyone at Denso, who kept striving with us, undaunted by all the failed attempts’.

The combination of Denso’s injectors and Toyota’s direct-injection engine technology overcame the obstacle of stable temperature control during combustion, bringing the dream of a 24-hour race appearance one step closer to reality.

The second story concerned technology for carrying hydrogen. Here too, Ito credited the existing hydrogen tank technology from the Mirai.

A tank that can safely store hydrogen on-board at high pressure and deliver it as fuel – Toyota had been developing this technology alongside the evolution of the Mirai, from first to the second generation.

The way that hydrogen is used in the Mirai, which is powered by electricity generated through the reaction between hydrogen and oxygen, differs from the hydrogen engine, which involves the combustion of hydrogen. Despite this difference, the technology for carrying hydrogen could be borrowed directly from the Mirai.

Looking at the actual race car reveals four tanks crammed into the space where the rear seats should be.

While the Mirai is equipped with three tanks of varying sizes (large, medium, small), the race car has a total of four – two of the Mirai’s medium-sized tanks, and two slightly shortened versions. In terms of capacity, the race car holds 180 liters compared to the Mirai’s 141. The car was packed with as many tanks as possible to maximize the driving distance on a single load of hydrogen fuel.

With the Mirai already on the market, its tanks have also cleared crash tests during development to ensure safety. That said, a race throws up vastly different conditions to city driving.

During a race, the car constantly runs at full throttle. As it turns out, this causes the temperature inside the hydrogen tank to steadily drop.

While cars developed for city driving are also tested under fairly rigorous conditions, a 24-hour endurance race is something else entirely. Even the engineers who had developed tanks for the Mirai and other fuel cell electric vehicles admit that the 24-hour race is ‘venturing into uncharted territory’.

To get the car race-ready, engineers also have to account for the possibility of high-speed collisions. Even if the car itself is not involved, it could be showered with fragments from a nearby impact. The car must be prepared for all such contingencies.

With this in mind, the team conducted a particular experiment during the development phase.

Known as a ‘penetration test’, it aimed to envision cases where sharp, high-speed projectiles could pierce the tank. As seen in the video below, a bullet-like object is fired at the tank at high speed to test whether safe conditions can be maintained.

Some other measures can be easily identified by looking at the vehicle. Carbon plates surround the four tanks in the area where they are housed, an example of the physical safety measures that have been put in place.

In part due to these carbon plates, however, the driver has zero visibility in the rear-view mirror. While this is common in full-fledged racing cars used by professional drivers, the upcoming race will feature non-professionals (known in the industry as ‘gentleman drivers’) such as Morizo.

According to the engineers, on race day the car will sport cameras, not installed during testing, that will allow drivers to check the rear via a monitor.

And finally, there is the story of the engine itself.

From the outset, the GR Yaris was a car built to win in motorsports.

Creating a production car first, then modifying it to compete in motorsports, was how Toyota used to do things. When Toyota rejoined the WRC, Akio himself acted to change this approach.

Begin by developing a car that can win in motorsports. Then turn it into a production vehicle that customers can drive. This is precisely how the GR Yaris was born.

Even after the GR Yaris went into production and sale, it continued to compete in endurance races and other events, constantly evolving through the cycle of break, fix, and repeat. This has become the way Toyota does things now.

The GR Yaris’s race-ready engine can handle high temperatures, high pressures, and high RPM.

The fact that this technology already existed lowered the hurdles when the team took up the challenge of building a hydrogen-powered engine.

This story gives the sense that Toyota’s various efforts, from competing in the WRC to building a hydrogen-powered engine, somehow all align in the same direction.

Comparing the hydrogen-powered Corolla to other cars in the race, the obvious difference is the rear seat crammed with fuel tanks. The combined weight of these four tanks turns out to easily exceed 100kg. Lugging this burden around a racetrack puts the car at a clear disadvantage.

Normally, racing vehicles are designed to be as light as possible to improve speed and fuel efficiency. Peeking into a race car, ordinarily you will see nothing but bare steel plates, with all comforts removed.

This time is no different – all parts that can be omitted have been. In their place, however, are many unfamiliar gauges, which seem to symbolize the real goal of taking part in this race.

The racetrack provides a challenging environment unlike anything found on urban roads or regular test courses. There is no telling what troubles will assail this new technology, but the team will need to deal with them on the spot to carry on racing.

With the hydrogen-powered engine having finally arrived at the starting line, this 24-hour race will serve as a proving ground that will help to elevate the technology into something that will serve the whole world.

At the April 22 press briefing, GAZOO Racing Company President Koji Sato, who oversees this project, made the following remarks.

As the engineer in charge of the hydrogen-powered Corolla, at the final test meet Sakamoto expressed his gratitude to all of the team members involved.