Hydrogen development today tends to focus on more prosaic transport, such as delivery vehicles, but Toyota’s projects err to the exciting.
Back in the 2021 Fuji 24 Hours race, it fielded a Corolla Sport powered not by a hydrogen fuel cell but by a specially developed H2 version of the three-cylinder GR Yaris combustion engine, and last month the car competed in the final of the Super Taikyu Series.
The Corolla runs on ‘boil-off’ hydrogen from liquid hydrogen carried in its fuel tank.
Burning hydrogen in a combustion engine generates no emissions of carbon monoxide (CO) or unburned hydrocarbons (HC), which are two of the three emissions cleaned up in a conventional petrol car by a three-way catalytic converter.
The third comprises oxides of nitrogen (NOx), and although the racing engine still produces some of that, the quantities are far lower than those produced by a petrol ICE, and they are neutralised by exhaust after-treatment.
The novel approach to using boil-off gas stems from liquid hydrogen’s unavoidable Achilles heel, which is that it literally evaporates while the car is standing doing nothing. Liquid hydrogen is stored in cryogenic tanks at a chilly -253deg C. Inevitably heat from the outside penetrates the insulated tank and the hydrogen begins to evaporate – it boils off.
A couple of decades ago, when modern hydrogen fuel cell and combustion engines began serious development, the high-pressure tanks for storing gaseous hydrogen at 350-700 bar, the go-to technology today, hadn’t emerged.
Most projects that focused on using liquid hydrogen and dealing with boil-off meant releasing it through a valve as pressure increased, which wasted a percentage of the fuel on a continual basis. If a car was left standing for long enough, it could run out of fuel without moving.
On the plus side, liquid hydrogen is far more energy-dense than gaseous hydrogen, with the potential for greater range.
What Toyota has done is turn boil-off into a positive: instead of simply venting the evaporating gas to the atmosphere, it captures it and uses it in several stages.
Boil-off gas is pressurised and fed to the engine and used directly as fuel to power the car. The pump that does the work increases the pressure of the boil-off gas by between two and four times, which is enough to fuel the engine.
Left-over gas is used to generate electricity in a hydrogen fuel cell stack, which is used to power a liquid hydrogen pump and other ancillaries. If there’s still a surplus after those steps, the excess is converted to water vapour using a catalyst and safely released outside the car.
Toyota is looking to form technical partnerships to develop the technology further.
This really cool idea (pun intended) emphasises the staggering levels of ingenuity that continue to emerge from the engineering departments of car makers worldwide.
Well, another year is over. What did we learn, collectively, as a species? Nothing. As a country (assuming your country is the United States)? Also nothing. What did you learn, as an individual? At least a few things. Will any of them help you avert the impending disaster that will one day be known to history as <insert capitalized phrase here> but for now is still just “2025”? Nope! Will they at least briefly soothe the pain inflicted on thinking people by the blazing dumpster fire that was the year 2024? I don’t know, let’s see.
Speaking of more where this came from, I have no doubt that the world will not get any smarter in 2025. But I wish you the best.
Olivia Troye is a Republican who worked as the Homeland Security advisor to former VP Mike Pence, but became an outspoken critic of Pence’s boss after leaving the White House in 2020. Among the things she’s criticized him for lately is his nomination of, shall we say, less-than-qualified candidates for many important positions.
One of those is his nominee for FBI director, Kash Patel, whose main qualifications seem to be love of conspiracy theories, subservience to Trump, eagerness to use the FBI to punish critics, and his efforts to educate youth via children’s books such as The Plot Against the King, in which Patel portrayed himself as a wizard helping defend “King Donald” from … well, you know.
Probably less interesting than J. Edgar Hoover’s book How to Tell If Your Parents Are Members of the Communist Party, but at least the artwork’s in color.
Troye is among many members of both parties who’ve criticized the nomination and Patel himself, and she said a couple of weeks ago (among other things) that she believed Patel would “lie about intelligence” (and not just his own), “lie about making things up on operations,” and by doing so had “put the lives of Navy SEALs at risk.” This prompted Patel to get his lawyer to threaten Troye with a defamation suit if she didn’t retract her comments.
Troye has a lawyer too, though, and he writes much funnier letters:
For email subscribers who may not get embedded images for a reason I haven’t yet figured out, Troye’s lawyer, Mark Zaid, thanked Patel’s lawyer Jesse Binnall for his letter and said he was replying on his client’s behalf. “I respectfully note,” he continued, “that many—if not all—of her statements have been previously or similarly stated by a wide swath of the knowledgeable population.” He also expressed doubts that the threatened lawsuit would “thrive.” But the important part is how he conveyed his client’s “intentions as to a retraction,” which was to post a picture of the French knight taunting King Arthur in Monty Python and the Holy Grail.
I don’t know whether there’ll be a lawsuit or how that might go, but the letter is terrific work. See also “Cleveland Browns Lawyer Letter Is Apparently Real” (Mar. 18, 2011) (discussing the best response to a cease-and-desist letter ever written, just attaching the original and stating “I feel that you should be aware that some a$$hole is signing your name to stupid letters.”).