are working on liquid hydrogen storage for airplanes. They claim they have largely solved the boil-off problem, so storing rather dense LH2 in relatively lightweight tanks isn’t impossible.
Yes, there are many hurdles to full-scale adoption and automotive applications are relatively more space-constrained than weight-constrained which is the opposite of commercial aircraft. But lots of smart folks backed by semi-smart money are pursuing all avenues.
This will be a very interesting space to watch over the next 20 years. Vast fortunes will be made and lost.
I suspect fueling with LH2 works fine if you’re going to fill the tank from empty to full and then use it all at a rate that matches or exceeds the boil-off rate, as an airliner might do. But for a passenger car that may be driven only/mostly on short trips over a span of many days (while spending most of that time span parked), I’m wondering just how good their aircraft boil-off solution could be.
A nitpick: that 350 Chevy only made 350 hp using the old and unrealistic gross hp rating. It’s not comparable with modern net hp ratings. As installed, the 1969 350 made around 260 net hp.
I’ve read several more in-depth articles in the aviation trade press about these folks. Part of their big idea is the tanks are interchangeable and rather than refueling an airplane, you unhook the empty-ish tanks, forklift them out, and slide other full tanks into place. The tanks are shuttled by truck back to a regional H2 factory / refinery / transfer station to be refilled.
The tanks are expected to sit outdoors and full for two days before any boil-off occurs. They have some catalytic method to render the gaseous H2 inert as it does exhaust. The amount of boil off beyond the two days starting point is supposedly negligible for up to a couple of weeks. At least for aircraft-scale tanks. A smaller tank for an automobile would suffer more from the volume/surface area equation.
Do I believe 100% of what they claim? Not exactly. But these folks are far past “artist’s conceptions”. It’s at the real full-scale, albeit prototype, hardware stage of development.
is this model a good fit for personal automobiles? Probably not. For local-use fleet vehicles be they cars or trucks? Possibly / Probably.
Something I learnt in my time in the geophysics arena. Claimed resources always significantly lag behind the real quantities of a resource. Mining and oil companies have a baked in disincentive to find new resources quickly. Which sounds odd. The problem is that a permit to explore both costs money up front, and comes with significant additional costs and responsibilities once found. Typically a company will bid for and acquire an exploration license with a use by date. There is a use it or lose it build in. If they find a useful resource they will need to apply for production licenses, whihc include the royalty paid to the country/state. These also come with use by dates. The upshot is that the proven reserves of any mined commodity tends to sit at a pretty constant number of years of available resource. Say about 10-20. There are significant disincentives at play that keep it there. Whenever you hear that there is only 10 years of a mined (or drilled) commodity, you can be pretty sure it is quoting proven resources.
The expectation of what there is to be found can be vastly higher, but more speculative. You can take a proven resource to the bank.
Ah, thanks, very interesting, but that makes me wonder: how did European brands of high powered cars like Mercedes Benz, Porsche or Volvo cope with the strict American emission laws? Did they have to cripple the power of their engines (a thing Porsche at least traditionally hates doing), too, or did they find other means?
A nitpick on your nitpick. 350 gross HP would come out to a hair under 300 HP. The difference between net and gross was 15 to 17 percent, as borne out by 1971 ratings published that published both ratings. The spread would also be larger if the engine is equipped with single exhaust. The top rated SBC 350 engine was 370 gross BTW, which translates to 314.5 net hp.
They did, but to a lesser degree. In some cases, for example, the European version with fuel injection would be specced out with carburetors, but yes, not at all uncommon to see the higher performance cars of Europe and Asia with detuned engines in US trim.
Those European “high powered” cars were anything but. Those late 70s Volvos barely cracked 100hp. A 1978 Mercedes 450 SL was about 180hp, as was the Porsche 911SC of that period. The European cars of the 50s, 60s and 70s made their marks by being lightweight with good handling.
As a big fan of Lotus, let’s consider their late 70s ‘supercar’, the Lotus Esprit. 140hp. The Ferrari 308? 240hp given a very generous reading of the dynamometer figures.
The problem with the 15-17% rule of thumb is it implies accuracy that isn’t there. The gross numbers were not only unrealistic, they weren’t consistent either. Some engines were overrated, some underrated. So any calculation using the gross hp rating is suspect.
The most accurate and most comprehensive means we have to determine the as-installed hp of an engine is to use the as-tested weight of the car and the 1/4 mile trap speed. The 1970 LT-1 Corvette hit 102 mph, possibly the highest trap speed for a stock small block of that era. It ran like you’d expect a 290hp car to run.
Is gross hp basically equivalent to crank hp, while net hp is roughly wheel hp? I read the Wiki on hp but don’t have the mechanical knowledge to quite figure it out.
Is the global standard for cars these days wheel hp, which is quoted as “bhp”?
Gross hp was what the engine made, at the crank, on a dyno. Usually, the engine had no air filter, alternator, water pump, or exhaust beyond the exhaust manifolds. Sometimes the carb and ignition were tuned for max power.
SAE net hp is the power at the crank, but with all accessories installed, tuned to stock specifications, run on pump gas, measured at standard temperature and humidity.
Wheel hp is net hp minus drivetrain losses.
Wikipedia tells me their Murai gets 400 mi / 650 km on 5.65 kg* of hydrogen. Although it seems capacity and range are improving, and those numbers may not all be from the same model year. Assuming the same capacity, I don’t know what kind of hit you take on losing the hybrid battery.
That may well be so, but it wouldn’t lead me to summarily low-ball the numbers by assuming the rating is inaccurate. Over the years we get to see engine builds, many of them to stock specs by the owner’s desire for historical accuracy, on a dynomometer. The results were surprisingly accurate, though they seldom came out exactly to the rated number, since the manufacturer’s liked numbers like “300” or “285” more than “301.4” or “283.7” or the like.
It’s nice with the passage of time to compare modern builds of stock classic engines and it’s been verified that one way of underrating engines was by half-truthing the dyno curves by publishing the rating at a point lower than the peak.
Probably the best truth teller of output, especially in comparing cars of similar weights, and as long as the gearing isn’t profoundly disadvantageous. ( losing acceleration room due to a poor start or botched launch )
( Brain farted ( forgot ) and thus missed the edit )
I’d say a 3500 pound-ish C2 Corvette going through the traps at 102 mph is making at least 290 net hp for sure*.
my “bench racing” wisdom
Another factor seen is some of the highest performance versions of an engine were throttled by factory, or even indifferent tuning. Ram Air IV Pontiac GTOs ( and Firebirds ) were generally low 14 second 98 mph cars off the showroom floor, but given some fine tuning of timing and mixture, were 105, 106 mph cars. I’ve seen them run myself.
Dwelling on it all further, it seems the generally crappy rubber of the day, compared to today, really hampered both traction…and handling. It doesn’t turn them into autocross machines, but makes them surprisingly competent and livable.
In the early 1990s I checked out some science book from the library (think it might have been published by Popular Science) while doing research for a science fair project. I remember an article in that book about how scientists/engineers were working on building a ceramic engine, which could run much hotter than a traditional aluminum or iron one, and therefore run more efficiently. That evidently didn’t actually pan out, but it’s an interesting idea.
Jim Wangers at Pontiac did more than just fine tuning to get better numbers in a magazine. On one occasion, a Firebird or GTO ran so fast, the magazine editors suspected foul play. They found that the “400” was actually a 428!