At this year’s Fuji 24 Hours endurance race, the hydrogen fueled Corolla hatchback made a premier appearance. This event was 2021’s third round in Japan’s long-running Super Taikyu endurance series. Big name drivers like Toyota CEO Akio Toyoda, former F1 and Le Mans driver Kamui Kobayashi, SuperGT wheelman Hiroaki Ishiura, Takuto Iguchi and Takamitsu Matsui were all in attendance. The Corolla only ran for half the time (twelve hours), completing 358 laps or 1,015 miles.
Initially, you might think the Corolla is similar to the second generation Mirai fuel-cell vehicle, but it’s not. This Corolla uses the same 1.6-liter, three-cylinder internal combustion engine as the GR Yaris (not available in the United States). Toyota had to modify the fuel delivery system, fuel injectors and ignition system to accommodate the hydrogen but otherwise the systems remained the same. The Toyota team could just have ran the GR Yaris, but the Corolla offered extra cargo space to house four tanks of compressed hydrogen. These tanks were taken from the Mirai with two modified and two stock variations. Using a specially designed carbon fiber brace, the tanks were secured in place and designed to stay intact in case of a high-energy or speed crash. The piping and fuel management system were taken directly from the Mirai, too. Though, the fuel injection system was a new design for the Corolla. Corolla’s chief engineer, Naoyuki Sakamoto stated, “Controlling combustion was our biggest challenge. Hydrogen combusts very fast and that sometimes causes pre-ignition.” The fuel injection system was designed with Denso. In reference to Denso, Sakamoto said, “They have been a huge support for us.”
The problem with hydrogen is the faster burning fuel. With a combustion rate of seven times that of gasoline, the car could only run about ten laps before it needed to be topped off. The Corolla refueled 35 times, wasting 5-6 minutes at each fill up. With all the miscellaneous stops, the Corolla spent a total of four hours in the pits. It also experienced some electrical problems not related to the hydrogen fuel system. Sakamoto explained, “The purpose of our entry is not racing. We were constantly checking data from fuel injectors and such, maintaining the engine and mobile refueling.” Just to run this Corolla, special hydrogen tanker trucks were brought in and parked outside of the pit lane.
The ultimate question is “why” use hydrogen when most of the world is focused on hybrid or battery electric options. Sakamoto responded, “Plug-in hybrids and battery electrics are just part of the solution, and Toyota believes it needs to provide several options. We need to study another option of achieving carbon neutrality using internal combustion engines. In Japan, fossil fuels are used to make electricity. The hydrogen we used, however, is produced from a solar panels.” He pointed out that many parts of the world will rely on ICEs for years to come. Gasoline-hydrogen combo fuel might be a viable option for mass-production vehicles. Toyota will continue to investigate alternative avenues to reach carbon neutrality.