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“Super Engine” may fundamentally change the way internal combustion engines work

166 points by Oatseller 11y ago

brianolson 11y ago
Large engines (in giant container ships) are supposed to be approaching the efficiency limit according to theoretical thermodynamics. Does this get small engines close to the limit?
- JorgeGT 11y ago
  I doubt it very much, since the main difference between the two are thermal losses due to size and speed.
elbigbad 11y ago
So, as I understand it, it combines the compression ignition of diesels with opposing pistons. The opposing pistons go toward one another and compress the air/gas mixture and ignite it. The exhaust escapes when the pistons move back through ports machined in the sides (kind of like a wankel/rotary engine removes exhaust gasses). Sounds like they're trading the spark system (a pretty easy to maintain system) for a second piston/crankshaft/etc. Essentially pulling out a cheap and perfected system for one that adds a bunch of high stress, expensive parts. Just from that sounds like a bad idea. They say the extra efficiency comes from heat loss from the cylinder head, but I have a hard time believing they're capturing that much extra (double-digits) efficiency from heat loss alone, especially given the reduced efficiency of having more moving parts.
- mjb 11y ago
  > Sounds like they're trading the spark system (a pretty easy to maintain system) for a second piston/crankshaft/etc. Opposing pistons and compression ignition are (mostly) orthogonal optimizations. From years of working on engines, I'd also be more willing to call the mechanical parts "perfected" and the ignition system "not perfected", at least for common consumer engines.
- digi_owl 11y ago
  Side ports are also used in 2-stroke piston engines. Most often found on mopeds and chainsaws.
  - Gracana 11y ago
    And big diesel engines.
  - taneq 11y ago
    This engine design is, in fact, 2-stroke according to the article.
    - digi_owl 11y ago
      It seems to lack a defining characteristic of your typical 2-stroke though, that the fuel is initially drawn in below the head to lubricate the crankshaft (this require mixing oil in the gasoline, done automatically on modern mopeds). https://en.wikipedia.org/wiki/Two-stroke_engine https://en.wikipedia.org/wiki/Two-stroke_engine
- mzs 11y ago
  You lose all the valve train.
- marssaxman 11y ago
  Sure, it's easy to maintain the ignition system, but it's also a system that needs maintenance: spark plugs, batteries, distributor caps, and alternators are all parts which wear out and need replacement during the normal course of vehicle operation. This is not true of pistons, crankshafts, and the like; it doesn't really matter that replacing them would be a difficult and expensive job, because they almost never break, and when they do you are generally better off just replacing the car and scrapping the old one. So, I think that an engine which had fewer of the former sort of components and more of the latter sort would, on balance, be a more reliable machine.
- deleted 11y ago
  [deleted]
Gravityloss 11y ago
Achates power has been running engines on test stands since 2011, I haven't heard of any engines installed anywhere. Maybe this kind of business is different compared to software where you're expected to build something revenue generating relatively quickly.
- zardo 11y ago
  That's why VC loves software, no billion dollar factories to build before you can start selling a product.
  - dtap 11y ago
    We have invested in a Company that has Chinese partners building the billion dollar factories for us. http://www.ecomotors.com/post/ecomotors-receives-new-investment-current-customer-zhongding-power-adding-funding-bill-gates http://www.ecomotors.com/post/ecomotors-receives-new-investm...
madflame991 11y ago
"The new engine will meld the best characteristics of gasoline and compression ignition engines with an innovative piston architecture refined by Achates Power that sets two pistons moving in opposition in one cylinder." We already have this technology. Diesel engines ignite the fuel through compression. We also had the opposing pistons layout for a while (https://en.wikipedia.org/wiki/Opposed-piston_engine https://en.wikipedia.org/wiki/Opposed-piston_engine). EDIT: we even have triangular-y shaped opposing engines (https://en.wikipedia.org/wiki/Napier_Deltic https://en.wikipedia.org/wiki/Napier_Deltic)
- tekacs 11y ago
  Granted you're absolutely right, but the article does seem to acknowledge this: "and allows the engine to run with diesel-like efficiency and power, while maintaining gasoline's emissions benefits." Whether or not any of this is actually feasible is explored in elbigbad's sibling comment.
- vmorgulis 11y ago
  Yes, BMW is known for a similar design: https://en.wikipedia.org/wiki/Flat_twin_engine https://en.wikipedia.org/wiki/Flat_twin_engine
  - digdugdirk 11y ago
    Not quite. The engine discussed in this article is almost the reverse of BMW's engine design. The crankshafts (where the rotational movement is transferred to the gear box) would be where the heads of the BMW engine are located. This means the explosion causing the rotational movement is at the centre of the engine, and keeps heat loss to a minimum. That's partly how they're going to get such high efficiency out of this design. The other way is the (I'm guessing) massive compression ratio they'll need to achieve for the auto-ignition of gasoline to occur.
    - hvidgaard 11y ago
      What I think, and this is without being ICE engineer, is the same effect that helps Mazdas SkyActive engines achieve high efficiency, higher compression and longer exhaust cycle. That a two stroke achieves a high power output is not surprising, and is one of the main reason they're used, as the power to weight ratio is superior to 4 stoke.
kenOfYugen 11y ago
There is this guy who has made some similar engine prototypes in this field of efficient opposed piston engines. PatOP: Single-Crankshaft Opposed-Piston Engine http://www.pattakon.com/pattakonPatOP.htm http://www.pattakon.com/pattakonPatOP.htm OPRE: Opposed piston Pulling Rod Engine http://www.pattakon.com/pattakonOPRE.htm http://www.pattakon.com/pattakonOPRE.htm > A 500cc two stroke can easily make some 80 Nt*m (8 Kp*m) torque. > At 6000 rpm this torque makes some 50 KW (70 PS). > 50 KW from 20 Kp means 0.4 Kp per KW. > And 0.4 Kp/KW with direct injection Diesel efficiency sounds interesting, especially for an engine with such a low cost."
KaiserPro 11y ago
cough I'm going to leave this here.... https://en.wikipedia.org/wiki/Napier_Deltic https://en.wikipedia.org/wiki/Napier_Deltic
- svachalek 11y ago
  It says in the first paragraph that it's diesel.
  - KaiserPro 11y ago
    From the parent article: The new engine will meld the best characteristics of gasoline and compression ignition engines with an innovative piston architecture refined by Achates Power that sets two pistons moving in opposition in one cylinder. As the crowns of the pistons slide toward each other, they compress a mixture of air and gasoline to such extreme pressures that the mixture auto-ignites without the need for spark plugs in a process known as compression ignition. which is the same principle as the deltic engine.
epx 11y ago
Opposed pistons is a way to have a very long stroke engine (high torque and smaller piston speeds = smoother), without the bigger radius that the crankshaft pin would have to rotate.
Houshalter 11y ago
This is not the same thing as from the article, or even a gas engine, but it reminds me of this project. I never found out what became of this: http://www.nytimes.com/2000/09/19/science/putting-a-darwinian-spin-on-the-diesel-engine.html?pagewanted=all http://www.nytimes.com/2000/09/19/science/putting-a-darwinia... >Dr. Senecal's test engine consumed 15 percent less fuel than a standard engine while producing one-third as much nitric oxide and half the soot.
- Cthulhu_ 11y ago
  > I never found out what became of this That's a common pattern in new (combustion) engine designs; there's a lot of them being published every year, but almost none of them actually end up being mass-produced and they dwindle into silence or as just demonstration models. Why? I don't know; the media only seems to focus on the invention and potential, not the failure (or if I were to put on my tin foil hat, the disappearance under mysterious circumstances). The only nonstandard engine that (AFAIK) ever got some leverage was the rotary wankel engine, and even that was (iirc) in just one car model.
  - semi-extrinsic 11y ago
    Mazda RX7 and RX8 had wankel engines. Nice cars, but higher maintenance than with normal engines. I think the main reason for the pattern you observe is that what's optimal and what's cost effective in a car is highly non-intuitive. Take front-wheel drive, for instance. Mechanically more complex than RWD, but (apparently) worth it due to the space savings inside the car. Or take water-methanol injection: well-understood tech that's been in use since WW2, can save fuel and reduce NOx emissions significantly, or give higher power output. But it requires changes to all the fuelling infrastructure, and that makes it essentially a non-starter outside of racing cars.
sologoub 11y ago
While not an earth-shattering amount, I'd rather see such grants/cost sharing go to tech that doesn't perpetuate dependence on fossil fuels. In the end, this tech only means we get to burn less, but not eliminate the emissions all together.
- sliverstorm 11y ago
  Combustion engines are so fundamental, they go far beyond fossil fuels. They are one of the best ways of converting chemical energy to work. Fossil fuels just happen to be very high in chemical energy. You can burn hydrogen, ethanol, bio-diesel, paraffin, methanol.... IMO the better combustion engines become, the more options for fuel we have. For example, ethanol compares poorly to gasoline in power & consumption, but with continued engine development, ethanol will be able to develop as much power & economy as gasoline does today.
  - erik_landerholm 11y ago
    But, when running E85 or E90 in a turbo charged engine you can run compression ratios equivalent to 100+ octane racing gas.
  - sologoub 11y ago
    Not familiar with burning paraffin, but of others only hydrogen produces relatively safe emissions (water vapor), the rest produce the undesirable by products. It would be better for smaller applications to move to electric and produce energy by other means. This requires investment into better batteries/storage applications. I'd rather all the money go to that instead of combustion research.
    - sliverstorm 11y ago
      Battery-powered 737's eh? While it's a nice dream, electric motors are way behind on power to weight ratio, thanks to batteries. We might get there someday, but we would need several stacking 10x improvements in battery tech, and who knows if they exist. There are still a lot of places where very high power to weight ratio of combustion engines is extremely important.
nickhalfasleep 11y ago
Opposed pistons have had good success in marine and railroad applications. https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diesel_engine https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diese...
- userbinator 11y ago
  And limited success in trucks: https://en.wikipedia.org/wiki/Commer_TS3 https://en.wikipedia.org/wiki/Commer_TS3
nimish 11y ago
HCCI is difficult enough--high compression ratio requires strengthened materials. Plus there's the hydrocarbon issues that come up with low temps. Maybe the heat retained by not having a cylinder head would be able to compensate? High temp burn/lean burn can lead to high NOx which is pretty bad if you need a urea injector system. Mazda, GM and others are known to be working on CI engines for gas targeting 2020, so this might be the next step in 10 years. Assuming we don't all switch to pure electric...
Torkel 11y ago
I'm assuming the purpose of developing a more efficient engine is to reduce emissions and thus "saving the planet"? That may seem commendable, but from what I have read it is actually a wasted effort, unless you can make it 99%+ more efficient (which you cannot). So, even if this engine is all that it claims (which most other comments here seems to question), it still uses oil and therefore is part of the problem and not the solution. (Wrote abit about this a while back with more references: http://torkeldanielsson.se/reducing-emissions-is-not-enough http://torkeldanielsson.se/reducing-emissions-is-not-enough) Edited comment: Man, I don't get hacker news... Why do you downvote this? I thought I was adding a valid and important point - that an increase in efficiency is fighting the wrong battle. I even added references via link. I would be super happy if I could be informed of what in this post is offending or off topic!
- dredmorbius 11y ago
  There are advantages and disadvantages to internal combustion engines. Compared to external combustion engines (steam engines), ICEs have much quicker start-up and response times. Steam engines require building up a head of steam, and actually exhaust the working fluid (water) over time, which is why steam railroads had water towers every so often. ICEs have been improved over more than 130 years, and scale from a few CCs of displacement to many cubic meters -- the smallest ICEs could fit in the palm of your hand, you could stand in the largest and not reach the sides or top of the cylinder. Liquid hydrocarbon fuels are exceptionally energy dense by both weight and volume. This makes certain classes of use very difficult to substitute for: commercial passenger and freight aircraft, overland truck transport, and powered marine shipping really have few tractable alternatives. Aircraft would all but disappear without liquid hydrocarbons (gasoline for piston engines, kerosene for gas turbines), trucks would probably be replaced with electrified rail, and shipping would return to wind power. Optimists might suggest nuclear marine powerplants, but I find that unlikely; ships are lost at far higher rates than is commonly realised: about 200 every decade, and existing trials of both military and nonmilitary nuclear marine power have proven it expensive and nonviable for all but the most demanding instances -- aircraft carriers and submarines. They're also quite stable in storage (proved over hundreds of millions of years), relatively safe to handle (no respiration or exceptional contact protection required), and their combustion products are mostly benign: CO2 (I'll get to this) and H20 with scant quantities of carbon monoxide, sulfer and nitrogen oxides, and other contaminants or partial combustion products, all of which can be greatly mitigated with combustion and exhaust controls and treatment. The CO2 exhausted isn't a problem in itself but for the, um, slight problem that in the past 200 or so years humans have returned to the biosphere carbon sequestered over several hundreds of millions of years. Which turns out to be a rather considerable problem. But it's only a problem where what you're burning are fossil fuels. There exist several options, though all much more expensive and/or constrained than present fossil fuels, for creating synthetic hydrocarbon-based liquid fuels. These also have challenges. Biofuels are intractable at scale given natural limits on plant production: what's called "HANNP" -- the human appropriation of net primary production -- or the photosynthetic ceiling. There's only so much plant growth which occurs and humans already consume much of it (40%, biofuel replacement of fossil fuels would consume another 20%, see Jeffrey S. Duke's "Burning Buried Sunshine" (2003), PDF available online, for more on this. Another prospect: sequestering carbon from the biosphere, and combining it with hydrogen, electrolised from water. The US Navy and national energy labs (especially Brookhaven), as well as M.I.T., have researched this for the past 50 years. It's proven expensive and hasn't been scaled past very low production (a few litres), but does work. It raises costs of fuel from one unit of input energy per 20-40 units made available to two units per one provided -- that's a 40-80x increase in the real cost of fuel. Not cheap, but it might still be our best option.
vvanders 11y ago
I thought that gas based engines topped out at 30% due to the heat loss intrinsic with burning fuel(all that waste heat). Is this tackling that in some fundamental way or is it just an incremental improvement?
- dredmorbius 11y ago
  Carnot efficiency. 30% is pretty typical in land-based motive systems. Shipboard combustion engines and coal-fired power plants (of all things) are rated as high as 45% efficiency. This is based on input and output temperatures, more than anything.
  - vvanders 11y ago
    Got it, so a 1.5x improvement on 30% lines right up with 45%. That's where they're getting their 50% gains number from.
    - dredmorbius 11y ago
      Good eye, though it's not immediately clear that that's strictly edging in on Carnot efficiencies or if other aspects (two-stroke power cycle, valveless port-based design, eliminating cylinder-head heat loss -- on which, doesn't that eventually reach equilibrium temp anyway?, etc.) are to credit. I've seen a few other radical reciprocating energy designs, there are some interesting YouTube vids I should track down. I think "radial engine" might reveal something. New Zealand, possibly Australian engineering firm, IIRC.
  - dkuder 11y ago
    F1 "power units" are at 47% thermal efficiency but there a complicated hybrid system. https://www.formula1.com/content/fom-website/en/latest/interviews/2016/2/mercedes_-andy-cowell-on-more-power--more-noise-and-more-races.html https://www.formula1.com/content/fom-website/en/latest/inter...
- djcjcjdhc 11y ago
  Most IC engines are nowhere near the carnot limit, which is around 60%-70% in most cases. The majority of the efficiency losses come from excessive heat rejection in the engine block and also mass transfer in the exhaust. Most engine blocks are (in)conveniently made out of aluminum, which has a very high thermal conductivity, meaning more energy gets transferred to the cylinder walls and wasted during combustion. As a mechanical engineer, this engine design seems much more promising, however: http://liquidpiston.com/ http://liquidpiston.com/
digi_owl 11y ago
Unless its a engine that gets us away from using oil, its not a fundamental change.
- michaelcampbell 11y ago
  From burning oil, perhaps. Throwing oil into a mythical "Mr. Fusion" and extracting the mc^2 energy from it that way; yeah, let's do that! =)
yoha 11y ago
For the curious, [1] (via [2]) shows various engine designs. [1] https://imgur.com/gallery/bxzeN https://imgur.com/gallery/bxzeN [2] https://www.reddit.com/r/educationalgifs/comments/468290/a_collection_of_gifs_demonstrating_a_few/ https://www.reddit.com/r/educationalgifs/comments/468290/a_c...
ck2 11y ago
Hopefully DOE also has $9 Million or more invested into battery research for electric motors. But I guess $9 Million isn't unreasonable if it actually produces engines that automakers will adopt.
- DrScump 11y ago
  Heck, the Obama administration already blew at least $193 million in the Fisker debacle.
  - lern_too_spel 11y ago
    Government loans are supposed to be risky, or else they would simply be replacing private loans. The point is to put money towards projects that have large potential public benefit.
  - ck2 11y ago
    Note the government gives $10 Billion per year in ethanol welfare to corporations. We could take the loss out of that. In fact we could fund 50 more startups EACH YEAR with the ethanol subsidy. Some of them will work, some will fail, still would be same $10 Billion.
Osiris 11y ago
> The research is being conducted under a three-year project funded by a $9 million award from DOE's Advanced Research Projects Agency-Energy (ARPA-E) and an additional $4 million of cost share from the team members. So, the total cost of designing this prototype was $13 million? What's the size of the R&D budget for a typical automaker? To me this just shows that typically businesses are in the mindset of "business as usual" because it's what they are comfortable with rather than looking into radical, new, innovation.
mannykannot 11y ago
While several people have mentioned the Napier Deltic, there was also the Junkers Jumo 205 opposed-piston diesel aero engine of the early 1930s. http://www.enginehistory.org/Diesels/CH4.pdf http://www.enginehistory.org/Diesels/CH4.pdf Claims of innovative internal combustion engine designs that will be significantly more efficient than current ones show up every few months. They never live up to the hype.
userbinator 11y ago
Efficiency aside, big two-stroke engines, particularly diesels, tend to have a very distinctive sound. I guess this one, being also two-stroke and compression ignition, would probably sound somewhat like this: https://www.youtube.com/watch?v=mkH9QRaQJM0 https://www.youtube.com/watch?v=mkH9QRaQJM0 Even if they weren't all that much more efficient, I bet a lot of people who miss the 2-stroke diesel sound would want one in their car.
- kbart 11y ago
  Modern car engines are already very silent, but many drivers love roaring sounds (probably due to false logic that more noise == more power). Car makers know that and fake engine sound using audio system(0) on many cars without anyone actually noticing, so I don't see why it can't be done in this case too. 0. http://www.huffingtonpost.com/2015/01/23/fake-engine-sounds-car_n_6533596.html http://www.huffingtonpost.com/2015/01/23/fake-engine-sounds-...
- qbrass 11y ago
  Here's an opposed piston 2 stroke diesel. Basically the "Super Engine" that the article describes built in the 1930's, except it runs on diesel instead of gasoline. https://www.youtube.com/watch?v=MuvJIoUTA8k https://www.youtube.com/watch?v=MuvJIoUTA8k
tyingq 11y ago
Better tech detail here: http://achatespower.com/our-formula/opposed-piston/ http://achatespower.com/our-formula/opposed-piston/

166 points by Oatseller 11y ago

Large engines (in giant container ships) are supposed to be approaching the efficiency limit according to theoretical thermodynamics. Does this get small engines close to the limit?

JorgeGT 11y ago
I doubt it very much, since the main difference between the two are thermal losses due to size and speed.

elbigbad 11y ago

So, as I understand it, it combines the compression ignition of diesels with opposing pistons. The opposing pistons go toward one another and compress the air/gas mixture and ignite it. The exhaust escapes when the pistons move back through ports machined in the sides (kind of like a wankel/rotary engine removes exhaust gasses). Sounds like they're trading the spark system (a pretty easy to maintain system) for a second piston/crankshaft/etc. Essentially pulling out a cheap and perfected system for one that adds a bunch of high stress, expensive parts. Just from that sounds like a bad idea. They say the extra efficiency comes from heat loss from the cylinder head, but I have a hard time believing they're capturing that much extra (double-digits) efficiency from heat loss alone, especially given the reduced efficiency of having more moving parts.

mjb 11y ago
> Sounds like they're trading the spark system (a pretty easy to maintain system) for a second piston/crankshaft/etc. Opposing pistons and compression ignition are (mostly) orthogonal optimizations. From years of working on engines, I'd also be more willing to call the mechanical parts "perfected" and the ignition system "not perfected", at least for common consumer engines.
digi_owl 11y ago
Side ports are also used in 2-stroke piston engines. Most often found on mopeds and chainsaws.
- Gracana 11y ago
  And big diesel engines.
- taneq 11y ago
  This engine design is, in fact, 2-stroke according to the article.
  - digi_owl 11y ago
    It seems to lack a defining characteristic of your typical 2-stroke though, that the fuel is initially drawn in below the head to lubricate the crankshaft (this require mixing oil in the gasoline, done automatically on modern mopeds). https://en.wikipedia.org/wiki/Two-stroke_engine https://en.wikipedia.org/wiki/Two-stroke_engine
mzs 11y ago
You lose all the valve train.
marssaxman 11y ago
Sure, it's easy to maintain the ignition system, but it's also a system that needs maintenance: spark plugs, batteries, distributor caps, and alternators are all parts which wear out and need replacement during the normal course of vehicle operation. This is not true of pistons, crankshafts, and the like; it doesn't really matter that replacing them would be a difficult and expensive job, because they almost never break, and when they do you are generally better off just replacing the car and scrapping the old one. So, I think that an engine which had fewer of the former sort of components and more of the latter sort would, on balance, be a more reliable machine.
deleted 11y ago
[deleted]

Gravityloss 11y ago

Achates power has been running engines on test stands since 2011, I haven't heard of any engines installed anywhere. Maybe this kind of business is different compared to software where you're expected to build something revenue generating relatively quickly.

zardo 11y ago
That's why VC loves software, no billion dollar factories to build before you can start selling a product.
- dtap 11y ago
  We have invested in a Company that has Chinese partners building the billion dollar factories for us. http://www.ecomotors.com/post/ecomotors-receives-new-investment-current-customer-zhongding-power-adding-funding-bill-gates http://www.ecomotors.com/post/ecomotors-receives-new-investm...

madflame991 11y ago

"The new engine will meld the best characteristics of gasoline and compression ignition engines with an innovative piston architecture refined by Achates Power that sets two pistons moving in opposition in one cylinder." We already have this technology. Diesel engines ignite the fuel through compression. We also had the opposing pistons layout for a while (https://en.wikipedia.org/wiki/Opposed-piston_engine https://en.wikipedia.org/wiki/Opposed-piston_engine). EDIT: we even have triangular-y shaped opposing engines (https://en.wikipedia.org/wiki/Napier_Deltic https://en.wikipedia.org/wiki/Napier_Deltic)

tekacs 11y ago
Granted you're absolutely right, but the article does seem to acknowledge this: "and allows the engine to run with diesel-like efficiency and power, while maintaining gasoline's emissions benefits." Whether or not any of this is actually feasible is explored in elbigbad's sibling comment.
vmorgulis 11y ago
Yes, BMW is known for a similar design: https://en.wikipedia.org/wiki/Flat_twin_engine https://en.wikipedia.org/wiki/Flat_twin_engine
- digdugdirk 11y ago
  Not quite. The engine discussed in this article is almost the reverse of BMW's engine design. The crankshafts (where the rotational movement is transferred to the gear box) would be where the heads of the BMW engine are located. This means the explosion causing the rotational movement is at the centre of the engine, and keeps heat loss to a minimum. That's partly how they're going to get such high efficiency out of this design. The other way is the (I'm guessing) massive compression ratio they'll need to achieve for the auto-ignition of gasoline to occur.
  - hvidgaard 11y ago
    What I think, and this is without being ICE engineer, is the same effect that helps Mazdas SkyActive engines achieve high efficiency, higher compression and longer exhaust cycle. That a two stroke achieves a high power output is not surprising, and is one of the main reason they're used, as the power to weight ratio is superior to 4 stoke.

kenOfYugen 11y ago

There is this guy who has made some similar engine prototypes in this field of efficient opposed piston engines. PatOP: Single-Crankshaft Opposed-Piston Engine http://www.pattakon.com/pattakonPatOP.htm http://www.pattakon.com/pattakonPatOP.htm OPRE: Opposed piston Pulling Rod Engine http://www.pattakon.com/pattakonOPRE.htm http://www.pattakon.com/pattakonOPRE.htm > A 500cc two stroke can easily make some 80 Nt*m (8 Kp*m) torque. > At 6000 rpm this torque makes some 50 KW (70 PS). > 50 KW from 20 Kp means 0.4 Kp per KW. > And 0.4 Kp/KW with direct injection Diesel efficiency sounds interesting, especially for an engine with such a low cost."

KaiserPro 11y ago

cough I'm going to leave this here.... https://en.wikipedia.org/wiki/Napier_Deltic https://en.wikipedia.org/wiki/Napier_Deltic

svachalek 11y ago
It says in the first paragraph that it's diesel.
- KaiserPro 11y ago
  From the parent article: The new engine will meld the best characteristics of gasoline and compression ignition engines with an innovative piston architecture refined by Achates Power that sets two pistons moving in opposition in one cylinder. As the crowns of the pistons slide toward each other, they compress a mixture of air and gasoline to such extreme pressures that the mixture auto-ignites without the need for spark plugs in a process known as compression ignition. which is the same principle as the deltic engine.

epx 11y ago

Opposed pistons is a way to have a very long stroke engine (high torque and smaller piston speeds = smoother), without the bigger radius that the crankshaft pin would have to rotate.

Houshalter 11y ago

This is not the same thing as from the article, or even a gas engine, but it reminds me of this project. I never found out what became of this: http://www.nytimes.com/2000/09/19/science/putting-a-darwinian-spin-on-the-diesel-engine.html?pagewanted=all http://www.nytimes.com/2000/09/19/science/putting-a-darwinia... >Dr. Senecal's test engine consumed 15 percent less fuel than a standard engine while producing one-third as much nitric oxide and half the soot.

Cthulhu_ 11y ago
> I never found out what became of this That's a common pattern in new (combustion) engine designs; there's a lot of them being published every year, but almost none of them actually end up being mass-produced and they dwindle into silence or as just demonstration models. Why? I don't know; the media only seems to focus on the invention and potential, not the failure (or if I were to put on my tin foil hat, the disappearance under mysterious circumstances). The only nonstandard engine that (AFAIK) ever got some leverage was the rotary wankel engine, and even that was (iirc) in just one car model.
- semi-extrinsic 11y ago
  Mazda RX7 and RX8 had wankel engines. Nice cars, but higher maintenance than with normal engines. I think the main reason for the pattern you observe is that what's optimal and what's cost effective in a car is highly non-intuitive. Take front-wheel drive, for instance. Mechanically more complex than RWD, but (apparently) worth it due to the space savings inside the car. Or take water-methanol injection: well-understood tech that's been in use since WW2, can save fuel and reduce NOx emissions significantly, or give higher power output. But it requires changes to all the fuelling infrastructure, and that makes it essentially a non-starter outside of racing cars.

sologoub 11y ago

While not an earth-shattering amount, I'd rather see such grants/cost sharing go to tech that doesn't perpetuate dependence on fossil fuels. In the end, this tech only means we get to burn less, but not eliminate the emissions all together.

sliverstorm 11y ago
Combustion engines are so fundamental, they go far beyond fossil fuels. They are one of the best ways of converting chemical energy to work. Fossil fuels just happen to be very high in chemical energy. You can burn hydrogen, ethanol, bio-diesel, paraffin, methanol.... IMO the better combustion engines become, the more options for fuel we have. For example, ethanol compares poorly to gasoline in power & consumption, but with continued engine development, ethanol will be able to develop as much power & economy as gasoline does today.
- erik_landerholm 11y ago
  But, when running E85 or E90 in a turbo charged engine you can run compression ratios equivalent to 100+ octane racing gas.
- sologoub 11y ago
  Not familiar with burning paraffin, but of others only hydrogen produces relatively safe emissions (water vapor), the rest produce the undesirable by products. It would be better for smaller applications to move to electric and produce energy by other means. This requires investment into better batteries/storage applications. I'd rather all the money go to that instead of combustion research.
  - sliverstorm 11y ago
    Battery-powered 737's eh? While it's a nice dream, electric motors are way behind on power to weight ratio, thanks to batteries. We might get there someday, but we would need several stacking 10x improvements in battery tech, and who knows if they exist. There are still a lot of places where very high power to weight ratio of combustion engines is extremely important.

nickhalfasleep 11y ago

Opposed pistons have had good success in marine and railroad applications. https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diesel_engine https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diese...

userbinator 11y ago
And limited success in trucks: https://en.wikipedia.org/wiki/Commer_TS3 https://en.wikipedia.org/wiki/Commer_TS3

nimish 11y ago

HCCI is difficult enough--high compression ratio requires strengthened materials. Plus there's the hydrocarbon issues that come up with low temps. Maybe the heat retained by not having a cylinder head would be able to compensate? High temp burn/lean burn can lead to high NOx which is pretty bad if you need a urea injector system. Mazda, GM and others are known to be working on CI engines for gas targeting 2020, so this might be the next step in 10 years. Assuming we don't all switch to pure electric...

Torkel 11y ago

I'm assuming the purpose of developing a more efficient engine is to reduce emissions and thus "saving the planet"? That may seem commendable, but from what I have read it is actually a wasted effort, unless you can make it 99%+ more efficient (which you cannot). So, even if this engine is all that it claims (which most other comments here seems to question), it still uses oil and therefore is part of the problem and not the solution. (Wrote abit about this a while back with more references: http://torkeldanielsson.se/reducing-emissions-is-not-enough http://torkeldanielsson.se/reducing-emissions-is-not-enough) Edited comment: Man, I don't get hacker news... Why do you downvote this? I thought I was adding a valid and important point - that an increase in efficiency is fighting the wrong battle. I even added references via link. I would be super happy if I could be informed of what in this post is offending or off topic!

dredmorbius 11y ago
There are advantages and disadvantages to internal combustion engines. Compared to external combustion engines (steam engines), ICEs have much quicker start-up and response times. Steam engines require building up a head of steam, and actually exhaust the working fluid (water) over time, which is why steam railroads had water towers every so often. ICEs have been improved over more than 130 years, and scale from a few CCs of displacement to many cubic meters -- the smallest ICEs could fit in the palm of your hand, you could stand in the largest and not reach the sides or top of the cylinder. Liquid hydrocarbon fuels are exceptionally energy dense by both weight and volume. This makes certain classes of use very difficult to substitute for: commercial passenger and freight aircraft, overland truck transport, and powered marine shipping really have few tractable alternatives. Aircraft would all but disappear without liquid hydrocarbons (gasoline for piston engines, kerosene for gas turbines), trucks would probably be replaced with electrified rail, and shipping would return to wind power. Optimists might suggest nuclear marine powerplants, but I find that unlikely; ships are lost at far higher rates than is commonly realised: about 200 every decade, and existing trials of both military and nonmilitary nuclear marine power have proven it expensive and nonviable for all but the most demanding instances -- aircraft carriers and submarines. They're also quite stable in storage (proved over hundreds of millions of years), relatively safe to handle (no respiration or exceptional contact protection required), and their combustion products are mostly benign: CO2 (I'll get to this) and H20 with scant quantities of carbon monoxide, sulfer and nitrogen oxides, and other contaminants or partial combustion products, all of which can be greatly mitigated with combustion and exhaust controls and treatment. The CO2 exhausted isn't a problem in itself but for the, um, slight problem that in the past 200 or so years humans have returned to the biosphere carbon sequestered over several hundreds of millions of years. Which turns out to be a rather considerable problem. But it's only a problem where what you're burning are fossil fuels. There exist several options, though all much more expensive and/or constrained than present fossil fuels, for creating synthetic hydrocarbon-based liquid fuels. These also have challenges. Biofuels are intractable at scale given natural limits on plant production: what's called "HANNP" -- the human appropriation of net primary production -- or the photosynthetic ceiling. There's only so much plant growth which occurs and humans already consume much of it (40%, biofuel replacement of fossil fuels would consume another 20%, see Jeffrey S. Duke's "Burning Buried Sunshine" (2003), PDF available online, for more on this. Another prospect: sequestering carbon from the biosphere, and combining it with hydrogen, electrolised from water. The US Navy and national energy labs (especially Brookhaven), as well as M.I.T., have researched this for the past 50 years. It's proven expensive and hasn't been scaled past very low production (a few litres), but does work. It raises costs of fuel from one unit of input energy per 20-40 units made available to two units per one provided -- that's a 40-80x increase in the real cost of fuel. Not cheap, but it might still be our best option.

vvanders 11y ago

I thought that gas based engines topped out at 30% due to the heat loss intrinsic with burning fuel(all that waste heat). Is this tackling that in some fundamental way or is it just an incremental improvement?

dredmorbius 11y ago
Carnot efficiency. 30% is pretty typical in land-based motive systems. Shipboard combustion engines and coal-fired power plants (of all things) are rated as high as 45% efficiency. This is based on input and output temperatures, more than anything.
- vvanders 11y ago
  Got it, so a 1.5x improvement on 30% lines right up with 45%. That's where they're getting their 50% gains number from.
  - dredmorbius 11y ago
    Good eye, though it's not immediately clear that that's strictly edging in on Carnot efficiencies or if other aspects (two-stroke power cycle, valveless port-based design, eliminating cylinder-head heat loss -- on which, doesn't that eventually reach equilibrium temp anyway?, etc.) are to credit. I've seen a few other radical reciprocating energy designs, there are some interesting YouTube vids I should track down. I think "radial engine" might reveal something. New Zealand, possibly Australian engineering firm, IIRC.
- dkuder 11y ago
  F1 "power units" are at 47% thermal efficiency but there a complicated hybrid system. https://www.formula1.com/content/fom-website/en/latest/interviews/2016/2/mercedes_-andy-cowell-on-more-power--more-noise-and-more-races.html https://www.formula1.com/content/fom-website/en/latest/inter...
djcjcjdhc 11y ago
Most IC engines are nowhere near the carnot limit, which is around 60%-70% in most cases. The majority of the efficiency losses come from excessive heat rejection in the engine block and also mass transfer in the exhaust. Most engine blocks are (in)conveniently made out of aluminum, which has a very high thermal conductivity, meaning more energy gets transferred to the cylinder walls and wasted during combustion. As a mechanical engineer, this engine design seems much more promising, however: http://liquidpiston.com/ http://liquidpiston.com/

digi_owl 11y ago

Unless its a engine that gets us away from using oil, its not a fundamental change.

michaelcampbell 11y ago
From burning oil, perhaps. Throwing oil into a mythical "Mr. Fusion" and extracting the mc^2 energy from it that way; yeah, let's do that! =)

yoha 11y ago

For the curious, [1] (via [2]) shows various engine designs. [1] https://imgur.com/gallery/bxzeN https://imgur.com/gallery/bxzeN [2] https://www.reddit.com/r/educationalgifs/comments/468290/a_collection_of_gifs_demonstrating_a_few/ https://www.reddit.com/r/educationalgifs/comments/468290/a_c...

ck2 11y ago

Hopefully DOE also has $9 Million or more invested into battery research for electric motors. But I guess $9 Million isn't unreasonable if it actually produces engines that automakers will adopt.

DrScump 11y ago
Heck, the Obama administration already blew at least $193 million in the Fisker debacle.
- lern_too_spel 11y ago
  Government loans are supposed to be risky, or else they would simply be replacing private loans. The point is to put money towards projects that have large potential public benefit.
- ck2 11y ago
  Note the government gives $10 Billion per year in ethanol welfare to corporations. We could take the loss out of that. In fact we could fund 50 more startups EACH YEAR with the ethanol subsidy. Some of them will work, some will fail, still would be same $10 Billion.

Osiris 11y ago

> The research is being conducted under a three-year project funded by a $9 million award from DOE's Advanced Research Projects Agency-Energy (ARPA-E) and an additional $4 million of cost share from the team members. So, the total cost of designing this prototype was $13 million? What's the size of the R&D budget for a typical automaker? To me this just shows that typically businesses are in the mindset of "business as usual" because it's what they are comfortable with rather than looking into radical, new, innovation.

mannykannot 11y ago

While several people have mentioned the Napier Deltic, there was also the Junkers Jumo 205 opposed-piston diesel aero engine of the early 1930s. http://www.enginehistory.org/Diesels/CH4.pdf http://www.enginehistory.org/Diesels/CH4.pdf Claims of innovative internal combustion engine designs that will be significantly more efficient than current ones show up every few months. They never live up to the hype.

userbinator 11y ago

Efficiency aside, big two-stroke engines, particularly diesels, tend to have a very distinctive sound. I guess this one, being also two-stroke and compression ignition, would probably sound somewhat like this: https://www.youtube.com/watch?v=mkH9QRaQJM0 https://www.youtube.com/watch?v=mkH9QRaQJM0 Even if they weren't all that much more efficient, I bet a lot of people who miss the 2-stroke diesel sound would want one in their car.

kbart 11y ago
Modern car engines are already very silent, but many drivers love roaring sounds (probably due to false logic that more noise == more power). Car makers know that and fake engine sound using audio system(0) on many cars without anyone actually noticing, so I don't see why it can't be done in this case too. 0. http://www.huffingtonpost.com/2015/01/23/fake-engine-sounds-car_n_6533596.html http://www.huffingtonpost.com/2015/01/23/fake-engine-sounds-...
qbrass 11y ago
Here's an opposed piston 2 stroke diesel. Basically the "Super Engine" that the article describes built in the 1930's, except it runs on diesel instead of gasoline. https://www.youtube.com/watch?v=MuvJIoUTA8k https://www.youtube.com/watch?v=MuvJIoUTA8k

tyingq 11y ago

Better tech detail here: http://achatespower.com/our-formula/opposed-piston/ http://achatespower.com/our-formula/opposed-piston/