Toyota's plans for hydrogen-powered, carbon-neutral race car go up in flames

TOKYO – Toyota’s plans to plug the potential of a new liquefied hydrogen carbon-neutral combustion engine at an endurance race next weekend went up in flames. Quite literally.

The modified Corolla race car caught fire during testing because of a leak in a hydrogen fuel line.

No one was hurt in the March 8 accident, and the driver managed to escape the vehicle after an emergency failsafe kicked in, Toyota said in a briefing Wednesday.

But technicians will not be able to get the car ready for its debut at a five-hour race in Japan’s Super Taikyu series scheduled for March 19 at the Suzuka Circuit in western Japan.

Toyota President Akio Toyoda had planned to take a turn behind the wheel in the race as part of his push to promote clean-burning hydrogen combustion technologies as one route to achieving carbon neutrality. He has raced cars with hydrogen-burning engines since 2021.

For the 2023 racing season, Toyota planned to introduce a new twist on the technology by using liquefied hydrogen. In the two previous seasons, Toyota’s entry had run on compressed hydrogen gas. All of the Toyota cars burn their hydrogen in an internal combustion engine, like gasoline.

They do not feed the hydrogen through a fuel cell to generate electricity, as in the Mirai sedan.

Liquid hydrogen can be a tricky fuel to handle, and it is sometimes the bane of space agencies that use it in rockets. An attempt last autumn by NASA to launch a giant moon rocket for its Artemis I mission was delayed because of a liquid hydrogen leak.

But Toyota executives said the fire, which occurred during a private test run at Fuji International Speedway, was unrelated to the car’s adoption of hydrogen fuel instead of gasoline.

The cause, the company said, was a pipe joint loosened by vehicle vibration.

“What I want everyone to understand today is that hydrogen was not the cause of this problem,” Tomoya Takahashi, president of Toyota’s Gazoo Racing Company, said at a briefing.

“Rather, it was the insufficient consideration of our design work,” he said. “Whatever fuel we used could have leaked and caught fire.”

Despite the setback, Toyoda ordered the team to continue working on the liquid hydrogen combustion technology, Takahashi said. The company wants to have the car ready for the next endurance series race in late May. That race will be a 24-hour run at Fuji Speedway.

Toyoda also will not let the incident deter him from buckling up in the vehicle. “He will continue to drive this vehicle because he is determined to show the safety of hydrogen,” Takahashi said.

The leak happened near the engine, and the hydrogen ignited because of the heat. A failsafe leak sensor automatically shut off the hydrogen supply, forestalling a wider fire.

The pipe joint may have loosened partly because the liquid hydrogen drivetrain weighs about 300 kilograms (661 pounds) more than the gaseous hydrogen system, aggravating the vibration. About 100 kilograms (220 pounds) of that weight is due to additional safety equipment. The joint segments are also replaced after every race, opening the possibility of an installation error.

Toyota is still troubleshooting the root cause and remedy, Takahashi said.

Using liquefied hydrogen has advantages over high-pressure gaseous hydrogen and traditional gasoline because it is much more energy dense. Given the same amount of weight, for example, liquid hydrogen packs about three times as much energy as gasoline, Toyota said.

The technology also has potential to be simpler and cheaper than gaseous hydrogen.

Liquefied hydrogen must be cooled to -253 degrees Celsius (-423 degrees Fahrenheit). But it can be stored onboard in a relatively simple insulated, vacuum-sealed Thermos-like tank.

Gaseous hydrogen must be stored in high-pressure tanks made of expensive carbon fiber.

Whereas liquid hydrogen needs just one large tank, gaseous hydrogen requires four separate tanks.

Liquid hydrogen can deliver 20 laps on a full tank, but gaseous hydrogen only 12.

Using liquefied hydrogen also allows for much more compact hydrogen refueling stations, because it does not need a special facility to boost pressure. This allows refueling in the pit.

Toyota wants to pursue hydrogen combustion technology for possible introduction to mass production vehicles, but that stage is a long way off and Toyota does not even float a timeline.

When the latest iteration of the hydrogen Corolla made a test run at Fuji Speedway in February, Toyota touted it as a world first for a liquid-hydrogen fueled vehicle to hit a racetrack.

Takahashi said Toyota tests new technologies under the stress of racing to root out potential problems early and speed up development. In that sense, the fire was a blessing in disguise.

“It’s not an accident or serious issue,” he said. “It’s a positive. We discovered something that was previously unknown. We are doing repeated tests to identify the issue.”