Even if it is 50% efficient, it generates a current to drive electric motors. How efficient are they? What's the gastank-to-pavement efficiency, and how does that stack up with today's efficient diesel engines? What about the little company does in Australia?
jriskin
· 1 year ago
Good electric motors are a very efficient and mature technology. High efficiency models reach 90-95%. But you can lose a little in the controller, wiring, motor, and transmission. Overall though, I wouldn't be surprised to see over 90% from input power to output shaft on a well designed system. So if this technology is really 50% efficient then you're talking about potentially a total system efficiency of 45% which is phenomenal.
commandersprocket
· 1 year ago
Shinigami, good info. thanks
This is a really elegant design. It reduces the complexity of the engine dramatically (no camshaft, flywheel, cams etc) . What is the downside? Is there potential for the magnets to demagnetize in the high heat, high force environment of the engine? I suppose your engine block for this engine is best built of non ferrous metals, so an aluminum engine block would be desirable (thought aluminum engine blocks are common enough now).
Tom_Craver
· 1 year ago
I noted on the lceproject site that one of the harder issues is preventing a head crash in the event of infrequent but probably inevitable mis-firing. Their solution appears to be very high speed, complex electronics to use the generator coil as a linear motor, braking the piston and then accelerating it back the other way, using power stored up in a capacitor. The hardest part of that appears to be the short interval from detecting misfire, to needing the piston braked to a halt and reversed direction.
What do you think of this idea: Since there's already permanent magnets in the pistons, position permanent magnets with poles opposed to those of the piston, such that in normal operation there is relatively little interaction - but when there is a mis-fire and the piston overshoots, the magnets rapidly close on each other, with the force between them increasing as the inverse square of distance - effectively acting as an immaterial, non-linear spring.
That could (a) prevent the piston from actually impacting, and (b) give the electronic system a wider time window in which to react and energize the coils to drive the piston back the other way, and (c) under normal operation any compression energy lost by interaction of the magnetic fields would be mostly returned to the piston as it is pushed the other way.
nextbigfuture12345
· 1 year ago
Multiple absolutely false claims. For example, only one moving part, frictionless, silent, eco-friendly. Multiple pointless claims. For example, small (standard ICE engines can be very small as well), adjustable TDC, possibility of recapturing energy from waste heat. Energy gains made by removal of a couple moving parts will probably be lost by the conversion of mechanical energy to electrical energy and back again. Two-stroke engines have a well-documented and long history of efficiency issues arising from the difficulty of efficiently and sufficiently evacuating exhaust gasses from the cylinder while simultaneously drawing fresh oxidizer.
You'd probably get cheaper and more efficient results by connecting an existing modern two-stroke engine to a generator or alternator. Better yet, use a modern four-stroke engine, which, while more complicated, is more efficient.
nextbigfuture
· 1 year ago
You have no research to support your assertions. MIT Technology Review and Sandia National lab researchers and other scientists are publishing peer reviewed research which indicates that the free-piston engine can achieve 50% or greater efficiency.
mike_murray
· 1 year ago
Interesting article. Please do not report that it is "free of friction" --- "It is small, has only one moving part, and is free of friction and noise..."
JasonR
· 1 year ago
When I first saw this and took a look at the iceproject.org website, I thought how great this would be in a plug-in hybrid like the Chevy Volt. While I was at that site or another site, I found a video of the prototype being tested and now I can't find it again but it is out there. In the video, the engine was VERY loud and didn't have a pleasing growl like some engines do. That said, I think some type of sound suppression would be required for a commercial application in a hybrid car.
Tesla patent 511916 of 1893 covers all the basic technology shown here, the reciprocating piston was driven by steam or compressed air, but the text also allows for other fuels. by using only one piston driven in both directions Tesla's patent eliminates the risk of piston/head collision, and he used it as a high frequency electrical generator. As other comments here say, it is certainly not friction free, and also the current generated in the coils will magnetically resist the travel of the piston rod/magnet assembly as would happen in a normal alternator when electrical load is applied to the output. Best to build a working prototype and test the overall efficiency from tank to pavement, as someone else here comments. As an ex motorcyclist on large two strokes I can vouch for the fact that they are very powerful, but NOT economical (as in fuel efficient) at all! Phil.
govindarajulu
· 6 months ago
hi i want do a project on fatigue life preduction of free piston engine mounting using FEM ,plz give me a related information
All Comments
This is a really elegant design. It reduces the complexity of the engine dramatically (no camshaft, flywheel, cams etc) . What is the downside?
Is there potential for the magnets to demagnetize in the high heat, high force environment of the engine?
I suppose your engine block for this engine is best built of non ferrous metals, so an aluminum engine block would be desirable (thought aluminum engine blocks are common enough now).
What do you think of this idea: Since there's already permanent magnets in the pistons, position permanent magnets with poles opposed to those of the piston, such that in normal operation there is relatively little interaction - but when there is a mis-fire and the piston overshoots, the magnets rapidly close on each other, with the force between them increasing as the inverse square of distance - effectively acting as an immaterial, non-linear spring.
That could (a) prevent the piston from actually impacting, and (b) give the electronic system a wider time window in which to react and energize the coils to drive the piston back the other way, and (c) under normal operation any compression energy lost by interaction of the magnetic fields would be mostly returned to the piston as it is pushed the other way.
You'd probably get cheaper and more efficient results by connecting an existing modern two-stroke engine to a generator or alternator. Better yet, use a modern four-stroke engine, which, while more complicated, is more efficient.
http://www.youtube.com/watch?v=pX3oAjnYZgc
Great Post!
http://thealternativeenergyinvestor.blogspot.com
Phil.