Toyota continues its push for keeping internal combustion engines, with a focus on carbon-neutral fuels such as hydrogen. In its latest breakthrough, Toyota tested liquid hydrogen in a GR Corolla race car at Fuji Speedway in late February.
Liquid hydrogen offers several benefits over its gaseous v…
Hydrogen power might not be the end-all solution, but I still think it's cool that Toyota is playing around with it.
Also interested to see more results from Porsche's E-Fuel.
Liquid hydrogen has some really weird attributes. It's got two different spin states, and if you simply liquify gaseous hydrogen the molecules will gradually transition from the more common one to the more stable one - releasing enough heat to boil the liquid H2. This is a solved problem during liquid H2 production by using catalysts, but it's weird.
It's a little tricky with regards to plumbing, too, it's a very small molecule and loves to leak. Remember how long it took NASA to finally get the SLS filled?
But you can legitimately call it rocket fuel because that's what SLS and the Shuttle use :) Now we need to strap some solid rocket boosters on the side for push-to-pass capability.
Toyota sold the Mirai in California and a couple other places ,
it is a Lexus class car running on hydrogen ,
The problem is the most of the Hydrogen filling stations are commercial or government owned like for buses and trash trucks ,
There is a Chevron station down the street that has a Hydrogen "pump" but there are not that many so the Mirai becomes a local commuter car ,
The Mirai runs on gaseous H2, not liquid, so it has a different set of challenges. I don't think you could fuel a normal car on liquid H2 because you'd have to maintain the fuel tanks at -450F all the time and be willing to vent off any pressure buildup - and I have bad news about what happens when you vent it. It doesn't take much for it to be highly flammable, and just for fun the flames are almost invisible.
https://www.nasa.gov/pdf/513855main_ASK_41s_explosive.pdf
The gaseous form just has to be kept under pressure, which is easy enough to do indefinitely if you don't have leaks. But it means you need big, heavy, shape constrained pressure tanks and it makes refueling a bit of an affair.
How does Lq Hydrogen compare to gasoline "octane"-wise?
Are you asking about energy density?
It's got more energy per pound than gasoline, roughly 3x. That's just the fuel, not the infrastructure like insulation. Good for racecar.
It's got less energy per volume than gasoline, about 1/4. So the tanks are going to be big for the same energy capacity, especially when you add insulation. For a race car, that's likely not a big deal because they don't need stuff like trunks or back seats.
https://www.energy.gov/eere/fuelcells/hydrogen-storage
From what I can tell, they're about half as efficient at turning that energy into actual mechanical work, but there seems to be a lot of potentially self-conflicting information here.
https://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm03r0.pdf (page 19)
californiamilleghia said:Toyota sold the Mirai in California and a couple other places ,
it is a Lexus class car running on hydrogen ,
The problem is the most of the Hydrogen filling stations are commercial or government owned like for buses and trash trucks ,
There is a Chevron station down the street that has a Hydrogen "pump" but there are not that many so the Mirai becomes a local commuter car ,
"it is a Lexus class car running on hydrogen." Fairly accurate description. I've driven a Mirai. It's as plush as a Lexus, but not as sporty as a Lexus, though, IMO.
Keith Tanner said:The Mirai runs on gaseous H2, not liquid, so it has a different set of challenges. I don't think you could fuel a normal car on liquid H2 because you'd have to maintain the fuel tanks at -450F all the time and be willing to vent off any pressure buildup - and I have bad news about what happens when you vent it. It doesn't take much for it to be highly flammable, and just for fun the flames are almost invisible.
https://www.nasa.gov/pdf/513855main_ASK_41s_explosive.pdfThe gaseous form just has to be kept under pressure, which is easy enough to do indefinitely if you don't have leaks. But it means you need big, heavy, shape constrained pressure tanks and it makes refueling a bit of an affair.
One side note: The Mirai uses a hydrogen fuel cell to power an electric motor. The GR Corolla uses hydrogen to power an ICE.
In reply to L5wolvesf :
I imagine "pretty high octane." It uses the same 3 cylinder turbo from the GR Yaris and GR Corolla and they make 300hp with 26 psi of boost pressure.
The hydrogen engine makes the same power but with the energy density I imagine the boost is turned up.
J.A. Ackley said:Keith Tanner said:The Mirai runs on gaseous H2, not liquid, so it has a different set of challenges. I don't think you could fuel a normal car on liquid H2 because you'd have to maintain the fuel tanks at -450F all the time and be willing to vent off any pressure buildup - and I have bad news about what happens when you vent it. It doesn't take much for it to be highly flammable, and just for fun the flames are almost invisible.
https://www.nasa.gov/pdf/513855main_ASK_41s_explosive.pdfThe gaseous form just has to be kept under pressure, which is easy enough to do indefinitely if you don't have leaks. But it means you need big, heavy, shape constrained pressure tanks and it makes refueling a bit of an affair.
One side note: The Mirai uses a hydrogen fuel cell to power an electric motor. The GR Corolla uses hydrogen to power an ICE.
Yeah, the Mirai is a really interesting critter technically. I was restricting my comments to the actual fuel types and what that meant. I'm pretty sure what's done with the hydrogen after it's extracted from storage is independent from the liquid vs gaseous question, as the liquid H2 will be a gas very shortly after.
In reply to j_tso :
So, keeping with the highly technical verbiage 'there be a lot mo power'. 
Thank you
Harry Metcalf just posted a video about how JCB is developing hydrogen powered heavy equipment, they claim it will have equal power and torque to their diesel powered machines.. It's pretty interesting, but the tricky part is still going to be how to source hydrogen economically. They talk about how in India the production process can be solar powered since they get so much sunlight there, but that won't necessarily work very well in northern England.
Super Taikyu is a great series, and if you're a bit of an insomniac like I am you'll be able to watch it live with english commentary on Twitch this year: https://www.twitch.tv/motorsportjapan
It's some people from dailysportscar.
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