This year’s Fuji 24 Hours endurance race saw a bit of an outlier on the starting grid. Among the many Nissan GT-Rs and Toyota GR Supras in the field was a small Corolla hatchback. At first glance, this wouldn’t seem to be a significant car to watch. But a closer look reveals its intrigue — it is powered by hydrogen.
The first vehicle we think of when considering Toyotas and hydrogen is typically the Mirai fuel-cell vehicle now in its second generation. However, it’s important to note that this Corolla Sport (the Japanese-market name for what we in the U.S. know as the Corolla Hatchback) is not equipped with a hydrogen fuel cell, a complex device that breaks down hydrogen to generate electricity. This Corolla instead uses the same 1.6-liter, three-cylinder internal combustion engine as Toyota’s firecracker GR Yaris that’s unavailable in the United States. The only modifications to make it run on hydrogen were the fuel delivery system, fuel injectors and ignition system.
In fact, the team could have run a GR Yaris instead, but utilizing the Corolla’s extra cargo capacity allowed them to stuff four tanks of compressed hydrogen in the rear. These tanks were plucked from the Mirai (two were modified for this application and two were stock), and they were secured in a special brace made of carbon fiber reinforced plastic and designed to withstand high-energy crashes should the worst happen.
Some of the hydrogen components, like the piping and fuel management system, had already been developed and were transplanted directly from the Mirai as well. There was no need to reinvent the wheel. However, the fuel injection system is new.
“Controlling combustion was our biggest challenge,” the Corolla’s chief engineer, Naoyuki Sakamoto, told us via a video call from Japan. “Hydrogen combusts very fast and that sometimes causes pre-ignition.”
The fuel injection system was developed in conjunction with Denso. “They have been a huge support for us,” Sakamoto said.
The Fuji 24 Hours was 2021’s third round in Japan’s long-running Super Taikyu endurance series. Despite a slate of big name drivers like former F1 and Le Mans driver Kamui Kobayashi, SuperGT wheelmen Hiroaki Ishiura, Takuto Iguchi and Takamitsu Matsui, and even Toyota CEO Akio Toyoda himself, the Corolla ran for only 12 hours, completing 358 laps or 1,634 km (1,015 miles). The winning Nissan GT-R NISMO GT3 put more than double that distance under its belt.
Super Taikyu veteran Masahiro Sasaki put down a fastest lap time of 2 minutes, four seconds. According to chief engineer Sakamoto, that’s pretty good, considering a Toyota 86 averages around 2 minutes flat. Drivers reported that the Corolla drove more or less like a normal race car, but that the faster-burning hydrogen fuel made the throttle a bit more responsive.
However, that faster burning fuel was also the car’s downfall. With a combustion rate of seven times that of gasoline, the car could only run about 10 laps before it needed to be topped off. The Corolla refueled 35 times, with 5-6 minutes spent gassing up at each instance. Adding for driver changes and other activities, the car spent a total of four hours in the pits. The Corolla also encountered electrical problems not related to the hydrogen fuel system.
“The purpose of our entry is not racing,” Sakamoto explained. “We were constantly checking data from fuel injectors and such, maintaining the engine and mobile refueling.” That last item referred to special hydrogen tanker trucks that had to be brought in and staged in a special area just outside of pit lane.
So with performance advantages that don’t outweigh the setbacks, why would Toyota spend the time and effort to develop a hydrogen-fueled race car? This seems especially fruitless in the U.S., where battery electrics have taken the lead while pundits question Toyota’s dogged devotion to hydrogen, in FCVs and otherwise.
“Plug-in hybrids and battery electrics are just part of the solution, and Toyota believes it needs to provide several options,” Sakamoto told us. “We need to study another option of achieving carbon neutrality using internal combustion engines.”
“In Japan, fossil fuels are used to make electricity,” he continued. “The hydrogen we used, however, is produced from a solar plant.”
He went on to point out that even if battery electrics are the ultimate end point, there are many parts of the world that will rely on ICEs for many years to come. Sakamoto even suggested that a gasoline-hydrogen combo fuel might be a possibility for mass-production vehicles. Existing ICE cars might even be able to be converted to use hydrogen fuel, as long as the fuel tank, fuel delivery, and injectors are changed.
For now, he only knows is that Toyota must pursue all avenues and alternatives to achieve carbon neutrality as soon as possible.