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New engine could save internal combustion from the scrap heap
- anamax 5y agoSteel can become soft at 1000F. I mention that because 60% efficiency on a 70F day requires a heat source of at least 900F. https://www.omnicalculator.com/physics/carnot-efficiency https://www.omnicalculator.com/physics/carnot-efficiency
- willis936 5y agoIs that true for all steels? High speed steel can be have a significant amount of tungsten in it.
- deleted 5y ago[deleted]
- tagoregrtst 5y agoThe walls dont have to be at 1000F. The gases in a piston engine are at > 1000F and the walls much cooler. This one reason why, in piston engines, larger pistons ate more efficient. Less heat loss through the walls
- JoeAltmaier 5y agoFlying cars, finally? 160hp at 35lbs is good
- aitchnyu 5y agoAny speculation about thermal efficiency and if you can't imagine this in a Kei hybrid? I imagine 25000 rpm and 300 psi turbos will be very noisy
- ScaleneTriangle 5y agoThe presentation says 60%
- gameswithgo 5y agowell if that is true it would be pretty revolutionary, its about double most piston engines
- mikewarot 5y agoAre there really sliding seals that are good enough to contain a combustion reaction while handling an occasional redlining at 25,000 rpm, and capable of lasting for decades of service? If so, then the fact that you can have two involute shaped mating surfaces as valves (almost no sliding, just a rolling contact), and a rotor that could be statically and dynamically balanced to almost zero vibration, would be amazing.
- PostThisTooFast 5y agoI wondered that too, but isn't that pretty much what pistons are required to be anyway? It seems like this thing could rev really high, since there's no herky-jerky motion.
- amluto 5y agoWhy ever vary the speed? At this point, most of the parts of an EV are quite mature, and the overall system is a lot more straightforward than a conventional ICE car. A rear motor (or pair) can drive the real wheels without a transaxle or multi-speed transmission. Traction control can be achieved by rapidly adjusting torque. Regenerative breaking massively increases brake lifetime and reduces particulate emissions. 4WD is relatively inexpensive and increases efficiency (because the front and rear motors can be optimized for different operating regimes, and one can be turned off whole cruising). An electric A/C compressor can operate at the optimal speed for the A/C without regard for driving conditions. A small battery pack that can produce plenty of power for bursts of acceleration under anything except racing conditions is essentially a commodity. So I think a series electric car with a 150kW (not kWh, and only supplying 150kW in brief bursts) and a small, highly efficient 30-40kW gasoline engine would be fantastic. And that engine would not need to have low efficiency and high emissions while warming up at low speed — when it turns on, it could immediately run at its optimal operating point even if the car is stuck in traffic. Heck, a manufacturer could sell the engine as an optional feature — many customers could simply skip the engine and drive the car as a short-range EV.
- PeterisP 5y agoIIRC that's how many diesel locomotives work, using electric transmission (generator+motor) instead of mechanical coupling.
- inamberclad 5y agoI don't understand the "very low or no emissions" statement. It's burning anything with carbon in it, it's going to produce CO2?
- ScaleneTriangle 5y agoCan burn hydrogen.
- gameswithgo 5y agoso can a piston engine
- gameswithgo 5y agothey are claiming double the efficiency so it would be half as much co2 for a given workload, but history and jevons paradox tells us cars would just get bigger and heavier and more powerful to eat up the gains!
- smilekzs 5y agoThe reason passenger cars have gotten bigger and heavier so far can be mainly attributed to 2 reasons: (1) more room for passengers and luggage (2) safety requirements. I think they are both starting to hit the "diminishing returns" stage, so a little more efficiency could potentially go a long way.
- engineer_22 5y agohttps://astronaerospace.com/ https://astronaerospace.com/ Their website is long on promises short on details. No pictures or videos of their purported prototype.
- mhandley 5y agoSecond half of this video shows how it works, with a very short clip of a test engine at the end: https://vimeo.com/644769736 https://vimeo.com/644769736
- GravitasFailure 5y agoI also love the blurb they have: "Note: This technology is projected to be capable of flying through a flock of birds, volcanic ash, smoke, and sand without skipping a beat, as well as the highest altitude flying capability that exists. Also does not require rotor seals at all. Tight tolerances and high RPMs solve that problem, not enough time for the air to leak when running!" The Motor Trend article[0] they link has a video of it being used in a ducted fan configuration. They might be able to avoid particulate intake to the engine itself (just like every other reciprocating engine with a filter), but sandblasting the fans or smacking them with a bird is pretty guaranteed to cause damage to the prop or fan at a minimum, and still has a likelihood of torqueing the engine in a way that damages the seals and bearings. It's cool, it's promising, but no prototype and high claims? I am extremely skeptical. [0]https://www.motortrend.com/features/might-new-concept-rotary-range-extender-fly-technologue/ https://www.motortrend.com/features/might-new-concept-rotary... edit: I just saw that their video has all of five seconds of an extreme close up of their prototype. I'm still not persuaded.
- eightails 5y agoSounds similar to experimental designs by Rolls Royce for a diesel rotary during the 60s, in that it uses two separate parallel shafts and rotors for intake/compression and ignition/exhaust. > In the case of the Rolls-Royce Wankel Diesel, the fuel-air mixture is first compressed by the lower rotary, and the output of that engine (which would be like the exhaust valve of a conventional rotary) sends the compressed diesel/air mixture to the intake of the smaller upper rotary engine, where it’s compressed to ignite like a regular diesel engine. Seems like it had the same issues that have always plagued rotaries, primarily with apex seals. https://jalopnik.com/this-might-be-the-weirdest-engine-rolls-royce-ever-made-1797954082 https://jalopnik.com/this-might-be-the-weirdest-engine-rolls... https://youtu.be/1pDjwaqU0dU https://youtu.be/1pDjwaqU0dU
- deleted 5y ago[deleted]
- ew6082 5y agoI see no reason this thing wouldn't lose compression or backflow exhaust gas after wear-in, and wear-in would happen quickly with the cyclic load on those ball bearings. It's a pretty animation but unless they have some spring loading to press the upper and lower rings together the compression (and therefore efficiency) doesn't appear to be durable. There are also some limitations to having a single power stroke per revolution. This can be geared down, of course, but at an efficiency cost.
- yetihehe 5y ago> There are also some limitations to having a single power stroke per revolution. Unlike one power stroke per two revolutions? That engine has one stroke lasting a full revolution, modern four-stroke has power stroke lasting half of revolution, every two revolutions.
- ew6082 5y agoWhich is why we usually have multiple cylinders to deliver smooth power. A V8 is getting power on 4 cylinders each revolution, etc.
- anonymfus 5y agoSo which news happens more often, an introduction of the new kind of rotary ICE with a revolutionary animation, or of a cancer cure in a Petri dish? And who are Astron Aerospace?
- benlumen 5y agoThe RX-8 just ended up being a discontinued anomaly that needs specialist mechanics to get serviced, to my knowledge. Can’t see this taking off at this juncture unless I’m missing something.
- gameswithgo 5y agowell the claim of 60% efficiency would be 2x better than a normal car instead of 2x worse, that might inspire one to replace apex seals every five years
- atdrummond 5y agoI've never had a shop refuse to work on any of my many rotary cars I've owned. That said, as someone who is a massive rotary/wankel fan and who has seen plenty of rotary designers make the claim that "this time is different", count me as extremely skeptical.
- benlumen 5y agoFair enough, not sure where I heard that from. Maybe it's more troublesome in the UK, or just a misconception on my part.
- elihu 5y agoThis is kind of vaguely similar to LiquidPiston's engine[1], which is sort of like a wankel engine turned inside out. (This has a couple benefits. The equivalent of apex seals can be on the non-moving part of the engine and thus are easier to lubricate. Also, the combustion chamber can be made more closely to spherical, which in theory should improve efficiency and emissions quite a bit.) As of awhile ago, the LiquidPiston folks were working on improving longevity. Building a test engine that works is an impressive achievement, but getting it to last also requires a lot of careful engineering and testing. [1] https://news.ycombinator.com/item?id=25450477 https://news.ycombinator.com/item?id=25450477
- AtlasBarfed 5y agoIs this the "inverted wankel/rotary" that made the tech news cycle about a year ago? https://www.engineering.com/story/update-wankel-20-the-return-of-the-rotary-engine https://www.engineering.com/story/update-wankel-20-the-retur... Mazda also released the spark-compression gasoline engine in the current round of Mazda designs. PHEVs allow gas engines to run on the Atkinson cycle. Range extenders or an emergency recharger is about all you can use them for. We do need an ultracompact engine for what I think is a sweet spot for consumer transition: 100 miles of LFP battery range + a compact range extender gas engine until charging infrastructure is ready and fast charging works reasonably well.
- elromulous 5y agoNo, the thing you're talking about is [1], and is quite different from OPs link. That being said, I came here to point out that new engine designs have been showing for literally the last a hundred years. There's a reason basically only pistons have succeeded. Scaling + reliability is really hard in a thing that is literally in the state of combusting thousands of times a minute. That being said, the wankel (more specifically Mazda's 13b) is still my favorite engine design ever. [1] https://www.liquidpiston.com/ https://www.liquidpiston.com/
- AtlasBarfed 5y agoWhat are you favorites about it? I know they have great power:weight, but don't they have fundamental shortfalls in pollutants/emissions and (strangely, considering the weight advantage) fuel economy? How would a Wankel that only had to do recharging (fixed gear, etc) serve in that fashion? A scaled down rotary that was portable might be a good "oh shit I ran out of charge" portable recharger, but then again, a fuel cell might be better for that.
- nathanaldensr 5y agoThe reports of the death of internal combustion engines are greatly exaggerated.
- adolph 5y agoOf note in recent IC engine improvements is Koenigsegg's "Freevalve" technology [0, 1] which along with the motor featured in this thread [2] will be in the upcoming Gemera. 0. https://en.wikipedia.org/wiki/Camless_piston_engine https://en.wikipedia.org/wiki/Camless_piston_engine 1. https://www.thedrive.com/news/26267/koenigsegg-prepping-1-1m-co2-neutral-supercar-with-freevalve-tech https://www.thedrive.com/news/26267/koenigsegg-prepping-1-1m... 2. https://news.ycombinator.com/item?id=30157910 https://news.ycombinator.com/item?id=30157910
- helloworld11 5y agoI don't see the internal combustion engine being anywhere close to any scrap heap of history any time soon. Even if a certain subset of consumer cars are moving over to electric motors at an accelerating pace, there are still plenty of major hurdles against these engines for a while yet, and many, many practical applications in which these hurdles just don't let electric cut the ice in place of combustion and power. There are over 31 million joules, or just under 9 kWhr in a single liter of gasoline. I know of no consumer market electric motor or battery that comes even close to this density.
- nvelty 5y agoI get the feeling electrification of vehicles is going to happen in a geographically similar fashion to the American political divide. EVs work very well in urban areas, but are less ideal for rural use for the reasons you mentioned. There's also the cultural issue of it - working on cars is a classic pastime once you leave the cities and the anti-repair nature of EVs doesn't fit well with this.
- thelitbulb 5y agoI completely agree. I also wanted to add that ICE vehicles made after ~2010 (depending on manufacurer) also have an anti-repair nature. My Cruze has many parts that require dealership programming (encryption keys) before the ECU will talk with them. Like the ABS unit and fuel pump for example. There is no going back now. The age of new repairable cars has ended.
- helloworld11 5y agoIf this becomes more widespread, it will be a sad state of affairs. One basic hallmark of ownership absolutely should be the technical ability to personally repair your property or at least have it repaired by professionals entirely of your choosing. I really hope you're wrong and that a certain consumer demand ensures they keep existing. Auto makers locking you into their own dealerships with encrypted digital parts is the hardware equivalent of keeping all your digital "property" on a single giant platform instead of self hosting.
- AcerbicZero 5y agoI really don’t mind all the commuter cars going electric. It just frees up more spare parts for my race car, and potentially, more race cars if the mood strikes me. The sooner we can get the Walmart warriors into adult Power Wheels the better.
- credit_guy 5y agoI don't get it. How is this engine going to save internal combustion? Ok, it's a small engine with a lot of power, and probably has some cute technical details, but what's the efficiency? Almost one third of all greenhouse emissions come from transportation, which is the same as saying from ICE's. There are 2 ways to reduce that: replace ICEs with electric motors, or increase their efficiency. If you manage to double the efficiency of ICE's, you're doing as good as replacing half of the ICEs with electric motors. If you increase their efficiency by 20%, it's like replacing 20% of the ICEs with electric motors. So, yes, you could certainly revive ICEs, but only if you dramatically increase their efficiency. Now, a typical ICE has an efficiency of 25%. Nissan is working on an ICE with an efficiency of 50% [1]. That thing can save ICEs. Anything else, it's just word spinning. [1] https://www.greencarreports.com/news/1131416_nissan-claims-50-thermal-efficiency-from-engine-for-e-power-hybrid-system https://www.greencarreports.com/news/1131416_nissan-claims-5...
- johnklos 5y agoIt's funny how we have to wait for real and serious competition before we can get nice things. It took AMD, then Apple, to trounce Intel before we finally started seeing Intel take things seriously, and only now that the electric car trend is really taking off do we start to see real innovations in internal combustion engines. I have a 1981 Diesel Chevette which can get 50 miles to the gallon when driven at a steady highway speed. If that forty year old fully iron engine can get 50 miles to the gallon in a car that's as aerodynamic as a brick, then why aren't new cars getting 80 miles to the gallon? Is our technology really that shitty? Or is it that the carmakers have marketed performance and "sportiness" to us over efficiency? They certainly don't want to make engines that can last forty years and 750,000 miles, but that's another issue. So the real question is this: if we can have 80, 100, 150, perhaps even 200 mile-per-gallon combustion engines, and if we can grow biodiesel from algae and even produce it using processes which pull CO2 from the air, then how much energy and carbon output could we save by not building limited life batteries and by not suffering the waste of electricity transmission and storage? It's not all one thing or the other, and it never should be, but we've been milking the old internal combustion cash cow for so long we've virtually guaranteed her death, even though evolution of the internal combustion engine would be a net benefit.
- salamandersauce 5y agoPart of it is weight. Safety standards and other things have really ballooned the the curb weight of cars. A Chevette weighed at most 2000lbs. A new Chevrolet Sonic (which is also a subcompact)? 2800lbs.+.
- 7thaccount 5y agoEmissions is one thing, but performance is another big deal. Just look at a Volkswagen bug vs a modern car. Modern cars have 2-3 times the power and that comes at a cost. Another factor is safety. If we agreed (not suggesting this for obvious reasons) that everyone would just build ultra lightweight and fairly low power vehicles, I think 80 mpg is feasible, but probably a lot less safe.
- deleted 5y ago[deleted]
- ncmncm 5y agoThis is the second revolutionary ICE I have seen recently. There was another that was also sort of like a Wankel. In it the triangular Wankel rotor is static, and the combustion chambers rotate around it. They have a working model with transparent parts so you can watch how it works. Nothing in the Omega 1 presentation seemed to offer any clue how it works or why it is better. These engines both seem like viable general-avition engines to replace Lycomings and Continentals, because electric is not really up to the job. FAA should take initiative to get these approved and deployed, because nobody can afford to do it privately.
- KennyBlanken 5y agoThere are lots of interesting engine designs, but they almost always are either too difficult/expensive to make or unreliable outside of a dynamometer stand.
- FL410 5y agoEven better, these could be generation systems hooked up to an electric motor and energy buffer (battery). Put the prop on the motor, keep the whole transmission system electric, and stick one or more of these somewhere else making power.
- ncmncm 5y agoYou could put a little turbine in a Cessna or Beechcraft driving a generator and little-ish battery, and an electric motor driving the prop, and get the same benefit, but the cost and maybe weight would be higher in a place where both are critical. Still, FAA probably should look into pre-approving such a configuration, too.
- KennyBlanken 5y agoOr you can just do what's already done: drive a propeller off the turbine. Which is what's done in turboprop engines, the most efficient airplane propulsion system available. Nothing is more efficient under power; turbines are only inefficient at low power settings (descents, taxiing, etc.)