Toyota Tests Liquid Hydrogen Corolla in 24-Hour Race

A couple of weekends ago, while most motorsport fans were focused on Monaco and Indianapolis, Toyota President Akio “Morizo” Toyoda participated in the Super Taikyu Fuji 24 Hours at Fuji Speedway in Japan. It’s not unusual for automotive executives to race their own products, but few have done so in endurance races with a hydrogen-powered Corolla.

Toyota has been entering a hydrogen-powered vehicle in races for several years, using the track to gain insights into thermal efficiency. These insights have contributed to the development of the latest generation of internal-combustion engines, which the company unveiled to the public at the end of May.

Japan’s Auto Industry Explores Hydrogen as Vehicle Energy Source

Supported by its government, Japan’s auto industry has continued to investigate hydrogen as an alternative energy source for vehicles, as opposed to liquid hydrocarbons or batteries.

Commercially, this has mostly involved hydrogen fuel cells, though these have seen limited success among drivers, even in areas with hydrogen fueling infrastructure.

However, the hydrogen powertrain in the GR Corolla uses an internal combustion engine rather than a fuel cell. The project first participated in the 24-hour race at Fuji in 2021, achieving slightly more success in 2022.

In 2023, the car underwent a major change, switching from gaseous to liquid hydrogen fuel.

The hydrogen now requires cooling to minus-253°C (minus-423°F) instead of being filled into tanks pressurized to 70 MPa (700 bar).

Liquid hydrogen has nearly twice the energy density of gaseous hydrogen, although still only a third that of gasoline. Additionally, the logistics and equipment needed for cryogenic refueling at the racetrack are less demanding than those for pressurized hydrogen.

Liquid Hydrogen Tank Upgrade Enhances GR Corolla’s Performance

The GR Corolla houses the liquid hydrogen in a double-walled tank, which proved easier to accommodate than the four pressurized cylinders it replaced.

This year, the tank is 50 percent larger, storing 15 kg of hydrogen, and has an elliptical shape, presenting a technical challenge for supplier Shinko. Toyota rebuilt the car to accommodate the new tank and reduced its weight by 50 kg (110 lbs).

A high-pressure pump injects the fuel from the tank into a vaporizer, where it becomes gas before reaching the engine. In 2023, the pump had to be replaced twice during the race, costing the team hours.

For 2024, engineers designed a revised pump to endure the full 24 hours, but testing unveiled a fuel leak, leading to delays. This was less severe than the 2023 gaseous hydrogen pipe leak that led to a fire.

Challenges Faced During Race Impact GR Corolla’s Performance

During the race, the new pump had intermittent issues due to sloshing in the tank. Later, an ABS module failure sidelined the car for five hours. Although the team finished the race, they completed fewer laps in 2024 than in 2023.

However, 24-hour racing is incredibly challenging, and the race was not a total loss for Toyota.

The team met its goal of completing 30-lap stints between refueling stops. Although the new pump had some issues and didn’t need to run for the entire 24 hours, it didn’t require a single replacement, much less two.

Carbon Capture Device Raises Questions About Practicality in GR Corolla

I’m still puzzled by the carbon capture device on the car’s air filter, which stores CO2 in a small tank as the car drives. While a nice gesture, it seems symbolic.

Toyota’s development of the hydrogen internal combustion engine (ICE) has led to significant performance and efficiency gains. Switching to liquid hydrogen has reduced refueling times by 40 percent, enhancing its viability as a carbon-free fuel. However, production vehicles refueled with liquid hydrogen still seem unlikely.

Toyota remains optimistic about selling combustion cars that only emit water but acknowledges the need for immediate practical benefits beyond the chairman’s enthusiasm for racing.

“Hydrogen engine development has greatly enhanced our understanding of engine heat efficiency. It was a catalyst for this technology,” said Toyota CTO Hiroki Nakajima at the debut of the new 1.5 L and 2.0 L four-cylinder engines, designed to meet the EU’s new Euro 7 emissions regulations effective in 2027.

Read the original article on: ArsTechnica

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