Microengines could replace batteries

[PhotonBoy]

http://www.electronicsnews.com.au/articles/08/0c01a308.asp

"Microengines—measuring 3 by 3 by 10 mm in size—offer 200 to 1000 times greater energy density than conventional battery technology. A microengine-powered mobile phone, for instance, could run for two years on the equivalent of a squirt of cigarette lighter fuel and be recharged by simply swapping out the empty fuel cartridge....

Three variants of microengine have so far been made by the British researchers: a single-piston engine with a gear, a free-piston engine, and a micro-Wankel rotary engine. The single piston engine and the free piston engine are based on a two-stroke mechanism. These engines are designed to produce from 0.7 to 14 W."

 

[eluminator]

I'll take one, where do I buy it? Is it electric start, or do I need to pull a rope?

 

[hula]

I want a V8 powered flashlight!
Just one more step towards a nano future and all of its' benefits.

 

[Steelwolf]

Saw this article before. I think it is so weird that on the macroscopic level, we are condemning internal combustion engines as being inefficient, outmoded, a blight and a horrible source of pollution, and 2-strokes being even more so.

But at the microscopic level we are hailing it as the next great thing, the wave of the future, the device that would increase the scope of our portable world.

Realistically, would it be more efficient than today's finest batteries? Very likely. Would it be more efficient than today's best 2-stroke engines? Doubtful.

So is this as good as it gets? Will we, in 20 yrs, have a pollution problem from all the tiny portable gadgets that we'll be carrying? What would cars be running on? Would that prove to be the next great thing once they learn how to minaturise it?

 

[php_44]

I can see it now:
<ul type="square">
[*]Indoor smog from cell phones, laptops, and PDA's.
[*]Mandatory emissions testing for electronics - "hey buddy, the rings are shot on your laptop and it's burning a lot of oil. You're blowin' a lot of blue smoke, dude."
[*]Noise pollution - "What? Huh? I can't hear you - some guy just sat next to me with his Harley PDA. They oughtta put mufflers on those things!!"
[*]Legislation to ban second hand pollution from electronics in restaurants, etc.
[*]Some manufacturer starts selling electronics with batteries at a huge cost premium touting the benefits to the environment.....
[/list]
Goto start, repeat....

 

[Doug Owen]

It should, of course work at some level for the same reason a truck load of diesel fuel can go a lot further than a truck load of batteries can.

There are, as I understand it, a whole series of engineering issues with internal combustion engines having to do with volume to surface ratios alone. Then consider the problem of keeping anything spinning for two years. Making a watch is not trivial, and it isn't doing any real work. Several watts is a bunch of (mechanical) energy.

Strikes me as this is the sort of technology the spooks should normally be funding, only since it won't work without air (like in space, or under water) it's probably not of interest.

Fuel cells still strike me as an interesting potential 'quantum leap'. But until we find a source of really cheap itty bitty mechanics to keep those nifty little machines humming, I don't think I'll start setting aside money to buy one.

Doug Owen

 

[koala]

I don't know how many kWh fuel cells can give out but I know once it's becoming unstable it explodes(Terminator III)? Ok someone tell me it's untrue. /ubbthreads/images/graemlins/grin.gif.

Vince.

 

[MrAl]

Hello,

Im very glad you brought this up, cause i almost forgot,
i gotta bring my flashlight in for a tuneup and oil change
this week :-)

The micro engines sound cool, using very high rpm to
get to useable power levels. Will they ever work out
for the common flashlight? We'll see i guess. It takes
time to see what flies and what doesnt.

I'm still waiting for this one, along with super conductors
for the average application, and super conductors were talked
about since the early 80's.


Take care,
Al

 

[Zelandeth]

Okay...I don't care about what I have it *for* but I want one! Just because it sounds cool!

 

[LED_ASAP]

It is 2010 and you are enjoying deepwater diving...

Now you've dived to 300 meters and your primary flashlight run out of battery. You pumped you feast in the mid air---I mean water---shouted "YES!" and reached out for your backup light --- a sugar cube-sized light with a Z3A Luxeon powered by a microengine that is supposed to last 10 years on a canister of butane. Press the ON button, the light flickered once like the Solitaire in Peter's post, and then nothing---you realized the light needs OXYGEN to work. Now you need to decide if you want to remove the oxygen tube from your diving suite to power the light, or try to find your way out in the total darkness /ubbthreads/images/graemlins/frown.gif

 

[Tomas]

If they are talking about super tiny fuel tanks, then the oxy tanks to go with them could be just as small ...

I can see loading my twin Wankel solid state portable lighting device with what looks like a couple of CO2 cylinders - a silver one with red stripe and a green one ...

Remember that the amount of air a normally aspirated combustion engine uses is about five times the amount of fuel is that only about one fifth of the air is oxygen.

 

[Doug Owen]

[ QUOTE ]
Tomas said:
Remember that the amount of air a normally aspirated combustion engine uses is about five times the amount of fuel is that only about one fifth of the air is oxygen.

[/ QUOTE ]

Actually fuel air ratios are closer to 15:1, right? Assuming 100% Octane we have 2 (C8H18)+27 O2 going to 16 CO2+18 H2O. Meaning 1.32 pounds of gas needs 4.32 pounds of Oxygen, since as stated air is 20% O2, we'll need five times that much air.

For a while some torpedoes actually used (V8) gas engines and carried a *bunch* of Oxygen. Very fast, short range, but left a trail right back to the sub. Consider that the gasoline is about seven pounds per gallon, a liter of it weighs about two pounds. A liter of oxygen at 220 bar (3200 psi, an unrealistically high pressure) has only ten moles of gas, 320 grams, say ten ounces. We'll need 13 pounds of oxygen, or a 15 liter tank at 220 bar. Liquids are very much denser than gas, which is why rockets use *liquid* oxygen.

Now if we could insulate the laptop really well........

Doug Owen

 

[PhotonBoy]

What surprised me most in the article was: "A typical battery requires 2000 times more energy to manufacture than it will ever dissipate..." Wow!

 

[Steelwolf]

[ QUOTE ]
PhotonBoy said:
What surprised me most in the article was: "A typical battery requires 2000 times more energy to manufacture than it will ever dissipate..." Wow!

[/ QUOTE ]

That figure depends on how far back you want to measure. If we go from raw material extraction, refining the ore, refining the smelt, combining the materials, and finally, construction of the battery, it takes a lot of energy. Slightly less if you can use recycled material. If you want to add cost of transporting the material from extraction point to refining point to manufacturing point, the energy requirements would be higher. And we haven't even started looking at the energy cost of the machinery required to get the materials from raw to manufactured.

I'm sure that if they really had a good look at their wonderful new microengines, they would realise that it also took a lot of energy to get it made, maybe even more than that required for a simple Li-ion battery since the material needs to be extremely pure. And we still haven't seen the real life of the micro engine. What if you needed to bring it in for tuning every thousand hours? (Remember how smokey 2-strokes can get if you don't keep them in perfect tune?) What if the engine wears out too quickly and so proves unsuitable for general use?

I'm sorry for all the negativity. I just feel that researchers always hype up and claim all sorts of figures just to make their work look good against other competing technology. They get their million-dollar grants, multi-million-dollar patents and royalties, they get the public clamouring to use their wonderful new product and in the mean time, try not to let anyone find out the real cost of using it.

 

[doubleganger]

[ QUOTE ]
Steelwolf said:
[ QUOTE ]
PhotonBoy said:
What if you needed to bring it in for tuning every thousand hours?

[/ QUOTE ]

My guess is that to be cheap enough to be practical they would be nonrepairable/disposable.

 

[Steelwolf]

Yeah, at that size, they may not be repairable. Anyway, what sort of repair could they carry out? Bring it in and they use a scanning electron microscope to push a few microns of material on to the needed areas to rebuild the worn off parts? /ubbthreads/images/graemlins/smile.gif Would give a whole new meaning to the term "small repair bill".

 

[Ferrous]

Let's take a look at the failure possibilities. High RPMs to get reasonable power? Would you hold a router against your head if someone told you that the motor was guaranteed to shut off before the bearings failed? Would you hold your nose four inches from an exhaust pipe when you talk to your friends? Don't worry, the catalytic converter has a lifetime warranty.

 

[Steelwolf]

That brings up an image in my head. CSI investigating a death where the victim has carked it with a high velocity projectile track through the brain, entry through the ear, no exit wound. Apparently the victim's phone has a microengine that blew up, sending the micro piston flying out at high velocity like a bullet.

Now the team have to discover if the microengine was defective and prosecute the manufacturer, if someone tampered with it to cause the "accident", or if it was the victim's own fault for not bringing it in for the yearly service. /ubbthreads/images/graemlins/thinking.gif

Knowing the typical storyline, someone tampered with the phone to kill off the victim and make it look like an accident. Now the wild accusations can begin. /ubbthreads/images/graemlins/smoker5.gif

And the final twist: it was the victim's own fault for forcing the repairman to mod the engine for souped up performance, which is, of course, against company policy and so was done under the table and denied by everyone. Investigations reveal that this has been going on for some time and micro-rev-head culture is alive and booming, but some people, because of badly-trained or unscrupulous micromechanics, are getting dangerously red-lined microengines.
/ubbthreads/images/graemlins/dedhorse.gif

I've always wanted the chance to use that. /ubbthreads/images/graemlins/naughty.gif

 

[BentHeadTX]

Interesting but fuel cells will ultimately win,
Having a microengine in a McLux, an LGI, BB750 Z3A or Micro Illuminator would be interesting. I can see Charlie or Wayne putting nitrous oxide injection, a supercharger and running nitro methane fuel to eak out the last lux.
Imagine 10 years from now, the flashlights will be the size of an Arc AA and run a 5 day fuel cell blasting a ZZ3A 3 watt Luxeon at 400 lumens with variable output. The modders will have made adapters to fit higher voltage fuel cells to run the peltier cooling to get 1,000 lumens.