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Next Big Future reports:
Liquid Piston gets more DARPA funding for 30KW engine 30 times smaller than todays engines
DARPA has awarded LiquidPiston an additional $2.5 million to continue development of its 30kW X4 rotary diesel engine prototype, bringing DARPA's total funding of the engine technology to $6 million.
When development of the fully packaged engine is complete, the 30kW X4 engine is expected to weigh just 30lbs and fit into a 10" box, while achieving 45% brake thermal efficiency – approximately an order of magnitude smaller and lighter than traditional piston diesel engines, and also 30% more efficient. The efficient, lightweight, and powerful rotary Diesel/JP-8 X4 engine offers a disruptive power solution for direct as well as hybrid electric propulsion and power generation.
Seems we get a story about a wonderous alt-energy breakthrough every week that never pans out, can the humble Diesel engine be reinvented to become the "next big thing?"
(Score: 5, Insightful) by ElizabethGreene on Thursday July 05 2018, @05:27PM (7 children)
> The fuel source is still finite and getting continuously more difficult to find.
With a finite and shrinking fuel source, increasing efficiency is a good thing, no?
> maybe DARPA should be looking for innovations in batteries and motors?
Arpa-E has put piles of money into those technologies as well. e.g. partnering with MIT on grid-scale batteries [energy.gov].
We've made fantastic advances in battery technology, and I sincerely hope they continue. That said, there is a demand for portable power systems today that batteries cannot match yet. It's down to energy density. Diesel is 38-48 MJ/kilo, LiIon is 1.8 MJ/kilo. Even with the terrible efficiencies of combustion and amazing efficiency of electrics there is still a big gap there. If I need a power supply I can trust to overwinter in the Antarctic today, it's going to be Diesel.
Bias disclosure: I've worked on a bunch of diesel trucks and owned one. I prefer diesel to gas, but hate the smell of both. Also, I use electricity and am actively trying to purchase an EV.
(Score: 2) by JoeMerchant on Thursday July 05 2018, @07:53PM (4 children)
I never understood people who designed, built, or purchased live-aboard vessels with gasoline power. If I'm going to sleep on a bomb, I at least want it to be difficult to ignite (like diesel).
🌻🌻 [google.com]
(Score: 1) by Ethanol-fueled on Friday July 06 2018, @04:10AM (3 children)
Well, you're still pretty safe in craft like airplanes in which the wings are fuel tanks: Fuel tanks are flooded with nitrogen, so even if some magical spark somehow ended up in there, the fuel wouldn't ignite. You got a safe fuel storage system and everything else is just goddamn peachy, as the energy density of hydrocarbon fuel leaves room for a lot more leisure.
At this point I'd be more afraid of living on top of a LiION system that can experience nasty toxic fire at a relatively low barrier for catastrophic temparature runaways.
(Score: 2) by JoeMerchant on Friday July 06 2018, @11:11AM (2 children)
Whose fuel tanks? Where does this oxygen free nitrogen come from? The stuff I'm surrounded by all day long is ~20% oxygen, which is plenty to spark up with gasoline vapor and go boom, whereas diesel needs higher than atmospheric pressure to sustain an explosive flamefront.
For me the distinction is: sleeping. While I'm on a small plane, or in a car, there's a good chance to notice that something is wrong, and the whole trip usually lasts less than an hour (o.k. commercial flights go longer, but... they're powered by basically kerosene which is closer to diesel again - which: I've actually flown a 3+ hour trip watching fuel spray out from a crack in the wing skin, in the air it was just a wet streak, but after we landed great splashes of clear liquid were coming out as the wing bounced up and down while we taxied to the gate. For that matter, I used to live under the MIA climbout pattern and once in awhile we'd get jet-fuel rain from a passing plane, not every day, but probably once every couple of years - enough to keep brown spots on the leaves that faced the sky.
So, now, picture a liveaboard boat. What's the maintenance schedule like? I don't see any N2 systems covering the fuel tanks on any boats I've ever considered purchasing. Then there's the opportunity for leaky fittings, a house worth of electrical not-so-greatness, and the whole: 8 hours unconscious trusting this thing night after night. Clumsy evac routes, most of which put you swimming on water that's most likely going to have a skim-coat of fuel if the shit recently hit the fan...
🌻🌻 [google.com]
(Score: 1) by Ethanol-fueled on Friday July 06 2018, @10:22PM (1 child)
There are systems specifically designed to flood the unoccupied regions of fuel tanks with pure nitrogen rather than standard air. Those systems may not be in all aircraft, but they are in larger ones.
(Score: 2) by JoeMerchant on Friday July 06 2018, @10:50PM
And, I'm cool with flying in smaller, gasoline powered, aircraft for the aforementioned reasons, even if their wings may go boom when something unfortunate happens. I also think that gas powered speedboats are fun, lots of fun, and not any more scary than gas powered cars.
I'm just not cool with the idea of sleeping on a bomb with such a low ignition threshold, especially in a marine environment with all the attendant corrosion, mechanical stresses, etc. Especially when diesel is such a readily available alternative.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Thursday July 05 2018, @09:03PM
There are hundreds for sale on craigslist. Some for under $2000. Just do it.
(Score: 4, Informative) by mobydisk on Thursday July 05 2018, @10:15PM
Not according to Jevon's Paradox [wikipedia.org] which observes that greater efficiency increases consumption, rather than decreases it. Interesting, yah?