Liquid Piston Wanker - Page 1
Forum section: electronics / general

author: SgtRock
author_rank: Unknown
timestamp: October 26, 2012, 09:24:48 pm
content: Greetings EEVBees:--A new wrinkle in small engine design, see below link.http://www.popularmechanics.com/cars/news/auto-blog/liquidpistons-hyper-efficient-engine-turning-the-rotary-inside-out-13817971?click=pm_latest&src=spr_FBPAGE&spr_id=2687--Might turn into something, might not. Just remember an electric motor is 90 or more percent efficient, if you do not count the source of power."A thing of beauty is a joy for ever:Its loveliness increases"John Keats 1795 -1821Best RegardsClear Ether

author: tom66
author_rank: Super Contributor
timestamp: October 26, 2012, 09:34:01 pm
content: Electric motor is close to 95-99% efficient (ignoring drivetrain losses) including the source of power (which doesn't have an inefficiency as such -- it provides more power than is input), petrol engine is about 20-30%. Would be interesting to see if this goes anywhere - it may turn out that it's an invention that's too far behind to be picked up by an automaker.

author: ejeffrey
author_rank: Super Contributor
timestamp: October 26, 2012, 11:04:33 pm
content: I'm all for more efficient engine designs, this article has basically no useful details. A lot of the advantages they speak of can be also accomplished in piston engines. The piston engine in the toyota prius can already get 38% thermal efficiency, and that is on an engine on the market for 3 years--not a lab prototype. The VW TDI diesel engines I think are a hair over 40%. 57% would be still a huge improvement over that, but comparing to a "normal ICE" at 20% is a bit misleading. Likewise, traditional ICEs will also benefit from direct injection and the improved burn efficiency and increased compression ratios that allows.So the interesting thing about this engine would be if it can solve some of those problems in better ways -- can it offer improved power density compared to the prius-style atkinson cycle engine which gives up a lot of power density to improve efficiency? Can it provide high efficiency over a wide range of rpm and throttle input than an ICE? Will it be able to match or exceed the reliability and longevity we expect from conventional engines? Will it be able to do all this while meeting emissions requirements (i.e., will it be compatible with catalytic converters?)Competing against piston type ICEs is a bit like the string of failed optical/magneto-optical/holographic technologies that were going to replace mechanical hard drives as the storage density or $/GB kings. While those technologies all looked impressive, it is really hard to compete with a well established technology with the kinks worked out when the manufacturers are working hard to constantly improve the tech. Is this engine the "flash SSD" of the motor vehicle world? Could be, but I kind of doubt it.Ars technical had a good article about the tech the auto companies are working on to improve efficiency:http://arstechnica.com/features/2012/10/the-road-ahead-how-well-get-to-54-5-mpg-by-2025/

author: SgtRock
author_rank: Unknown
timestamp: October 27, 2012, 12:55:47 am
content: Greetings EEVBees:--Ejeffery has said "Is this engine the "flash SSD" of the motor vehicle world? Could be, but I kind of doubt it."--I completely agree. Like I said, maybe there is something here, maybe not. I was kind of hoping that perhaps somebody might have more information, pro or con, on this one. EJ also made some other good points, while showing a "ruthless skeptical scrutiny" Right on.--What we really need is one of these:"Electric motor is close to 95-99% efficient (ignoring drivetrain losses) including the source of power (which doesn't have an inefficiency as such -- it provides more power than is input."--Ah yes, an above unity gain device. It not only breaks even but it makes a profit. Our troubles are over. Eat entropic ergs Clausius and Kelvin."At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense."Carl Sagan 1934-1996Best RegardsClear Ether

author: tom66
author_rank: Super Contributor
timestamp: October 27, 2012, 01:03:56 am
content: Ah -- you spotted my, umm, "deliberate" error. (2am physics = bad idea.) I meant to say, it provides more energy from something like fuels/nature (coal, gas, or renewables.) than is put in to extract it. We don't really care about how much energy is wasted from the extraction process as long as a) that isn't harmful (CO2, other gases, etc.) and/or b) that the source isn't very limited (for example, oil.)So the efficiency (to us) is 100%. Otherwise, it would not be a power source, but a power sink.

author: SgtRock
author_rank: Unknown
timestamp: October 27, 2012, 01:21:53 am
content: Dear Tom66:--I kind of thought you were pulling my leg, you really had me going there, for a while.--But do not forget that you really ought to count the efficiency of the source of the electricity including transmission losses. In the UK 80% percent or so of the electricity is generated by conventional heat engines, at present, depending on whose figures you use. Take a Diesel Locomotive for instance. Its electric motors are very efficient, I agree, but it still burns Diesel in an ICE. By your argument, if I ran a cord from the ICE to the electric motors on the Locomotive, then the efficiency "to us" would be 100%, yes? I am still having a problem understanding how this helps anything."I'll have the Alfalfa sandwich, and the smashed yeast"Woody Allen 1935 -Best RegardsClear Ether

author: SeanB
author_rank: Super Contributor
timestamp: October 27, 2012, 06:29:17 am
content: Good respin, and hopefully seal tech has improved with time ( those Wankel seals were really poor if left to stand a month) but they had impressive output from such a small unit. Getting rid of a lot of the reciprocating mass will be good.

author: poorchava
author_rank: Super Contributor
timestamp: October 27, 2012, 08:19:57 am
content: With Wankel there is a problem: it doesn't give you better fuel efficiency, just better volumetric efficiency. This is because conventional piston engine outputs 1 work cycle per 2 revolutions, and wankel rotor performs 3 work cycles per one revolution. IIRC in Japan, for the purpose of tax calculation (which depends on engine displacement, amongst others) wankel engines have their displacement multiplied by 2.5 or something like that, to stand on the common ground with piston engines.My friens owns a 1.3L RX-7 with wankel, and i can assure you, that this is NOT a fuel efficient car (+cost of fully synthetic oil, which the wankel inherently consumes). Not sure how much does it typically consume per 100km, but definitely above 15L of gas.

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 27, 2012, 09:45:22 am
content: Newer designs are implementations are fair more efficient, the one in the RX-8 is much much better, that said, it isn't amazing, but isn't as much of a guzzler as the older 13Bs AND it don't have the issues of flat spots in the seals.

author: SeanB
author_rank: Super Contributor
timestamp: October 27, 2012, 10:29:53 am
content: Older ones are fuel hogs, but they wind up like a turbine, you just keep on going faster............

author: vk6zgo
author_rank: Super Contributor
timestamp: October 27, 2012, 11:42:55 am
content: Sounds a bit like Ralph Sarich's Orbital engineAfter he got finance,he spent a lot of time developing it,but eventually gave up & concentrated on making very efficient conventional engines,which he did extremely well.Sarich patented stuff pops up in engines made all over the world.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 27, 2012, 03:38:12 pm
content: Quote from: ejeffrey on October 26, 2012, 11:04:33 pmAtkinson cycle engines are only slightly different from normal ones - just a slightly different camshaft. They're well proven, being in use for over 10 years with an excellent reliability record. Emissions are very low as well.Something interesting to note is that the main reason why a hybrid (usually) gets better highway MPG than a non hybrid version of the same car is because the engine is Atkinson cycle, and has next to nothing to do with the hybrid system itself. Sure, you could put the same Atkinson cycle engine in a non hybrid, but it makes no business sense since that would cut into sales of the hybrid version. That's starting to change as automakers are looking into plug in hybrids.QuoteI remember reading that the latest hard drives (1TB and above) are magneto-optical drives.

author: djsb
author_rank: Super Contributor
timestamp: October 27, 2012, 03:46:55 pm
content: I thought this topic was about a new sex toy that someone has invented???Or are you all too polite to point out the mistaken name in the title?David.

author: ejeffrey
author_rank: Super Contributor
timestamp: October 27, 2012, 05:51:06 pm
content: Quote from: NiHaoMike on October 27, 2012, 03:38:12 pmThere is more to it than that. The atkinson cycle engines have lower power density (due to reduced compression stroke displacement) and for optimal cruising efficiency you want a smaller engine running close to full throttle. Such a small engine in a 4/5 person vehicle would be underpowered, at least by American standards. The hybrid drive train allows for the electric motor to provide an HP boost when you need it to get acceptable acceleration, while maintaining high efficiency the rest of the time. In the toyota (but not honda) hybrids the two electric motor/generators also acts as a CVT, allowing the engine to run at the optimal RPM more of the time.QuoteI don't think so. I think the current shipping drives are still straight magnetic. I have heard that the next generation of ~2 TB/platter drives (4,6,8 TB capacity) will use heat assisted magnetic recording. This is not quite the same as traditional MO drives where the laser actually reads the data, but if it comes to pass, I think it counts