[Licho]

Local university now reports, that they have finalized their prototype of Linear Combustion Engine. Type of engine without mechanical parts (like flywheel) that convert linear movement into rotatory.

Energy is instead converted directly to electricity and complex control circuits are used to control engine and keep it running.

This type of engine has higher efficiency than conventional ICE.

Suggested use is for hybrid cars, as main power source, instead of costly and material intensive fuel cells. Engine is mechanically very simple and can be mass produced cheaply, while achieving higher W/m^3 and W/kg than conventional fuel cells.

Project leader now says that after experimental prototype, full industrial prototype is being developed now.

This is somewhat outdated site which explain how engine works:
http://www.lceproject.org/

[Mesuge]

It looks good, however there were similar concepts in this area before and they did not make it on the market in the end..

It appears to me a notch easier from the mechanical part than Stirlings but LCE concept stands and falls with driving electronics/alghoritms so that's they have probably made a breakthrough if anything..

I'd like to have one for electricity generation from vegiee oil or some biowaste in case the sun is not shining for solar cells or wind is not blowing for wind turbine..

For automotive application it can not beat the full EV but it can serve as milage extender for those crazy long distance commuters..

[Licho]

Well they say they handled controlling it. It's currently using expensive high speed computer as a control unit, but new dedicated microchip circuity is ready too.

Because prototype works very well and can be controlled under variying load, they are now starting tests together with local car manufacturer Skoda on full industrial prototype for cars. They expect to be able to sell first commercial engines in 3 years.

This is TV report (not usefull unless you really want to see it running or understand Czech
http://www.nova.cz/tvarchiv/video/?video=39015

[Tanada]

Local university now reports, that they have finalized their prototype of Linear Combustion Engine. Type of engine without mechanical parts (like flywheel) that convert linear movement into rotatory.

Energy is instead converted directly to electricity and complex control circuits are used to control engine and keep it running.

This type of engine has very high efficiency, up to 80% energy contained in hydrocarbon or hydrogen fuel is transformed into electricity. This should lead to cars that 4x outperform current cars in terms of hydrocarbon energy -> work efficiency.

Suggested use is for hybrid cars, as main power source, instead of costly and material intensive fuel cells. Engine is mechanically very simple and can be mass produced cheaply, while achieving higher W/m^3 and W/kg than conventional fuel cells.

Project leader now says that after experimental prototype, full industrial prototype is being developed now.

This is somewhat outdated site which explain how engine works:
http://www.lceproject.org/

Based on the link provided the description is oddly worded. The horizontal oppossed engine is most definately mechanical, though no rotory parts are used. When I first read the description I thought they had developed a magnetohydrodynamic engine, which would be a massive coup! This appears to be a horizontal opposed two cylinder 2 cycle motor, which mimics a sterling engine and therefore acheives greater efficiency. The designers are to be applauded for ingenuity and I hope it works as advertized because it would have a huge number of applications if it does.

Hybrid cars are the least of it, for standby generators this system would be cheaper by far and more efficient than current systems. And it does not have to be spark engine design either, you could use the same two cylinder horozontal layout for low volume steam like a modern steam electric locomotive. No more fussing with pistons directly driving the wheels, instead the steam makes electricity and the battery pack drives the traction motors like you have on a diesel electric. Much simpler than a turbine and does not need the vapor suction for good efficiency.

[Licho]

Yeah you are right, it's badly worded, engine is mechanical ,but doesn't involve flywheel and stuff to convert linear movement of pistons to rotatory, that what I meant, sorry for confusion

[DR_STU]

A very interesting design. Increased efficiency and less complex, but I'm wondering about problems with combustion emissions since it is a two-stroke rather than four-stroke. I've heard that when comparing emissions from outboard boat engines that a two-stroke puts out 8 times the emissions of a four-stroke, mainly in uncombusted fuel. Perhaps the emissions from the above engine could be controlled if coupled to an advanced catalytic converter.

[FoxV]

This type of engine has very high efficiency, up to 80% energy contained in hydrocarbon or hydrogen fuel is transformed into electricity. This should lead to cars that 4x outperform current cars in terms of hydrocarbon energy -> work efficiency.

I'm vary skeptical about this claim.

Although it does look like a very efficient design. It still looks like it goes through a normal heat engine cycle, so can only have a maximum heat to mechanical energy conversion of 40%.

Even if it does not follow a normal heat engine:
The exhaust gasses have heat and chemical energy so there's losses there (cogen heat would help reduce this loss)
Mechanical to electric energy will have losses (typically 5 - 10%) for generating electricity
Then electrical must go back to mechanical (again 5 - 10% loss) for running the electric motors.
If this goes into battery storage, then there's losses for battery charging (5- 10 %) and discharging (another 5 - 10%)

My suspicion is that they mean this system is 85% efficient of the Carnot cycle for an over all efficiency of 35% which is a bit better than a well tuned standard ICE (30%?)

[Licho]

Yeah, you are right, that "4x" figure was extraggeration of some journalist who compared incomparable numbers, I unfortunatelly carried it over here.. Those numbers were nonsense, trying to fix topic name now..

[master_rb]

it seems to be similar to a boxer engine, i'm not an expert so can't express my opinion on the differences and which is better but just the base structure reminds me of the boxer

[VMA131Marine]

Even if it does not follow a normal heat engine:
The exhaust gasses have heat and chemical energy so there's losses there (cogen heat would help reduce this loss)

Although it would increase mechanical complexity a bit a turbocharger might be a good option to pressurise the air intake and recover some of the energy in the exhaust.

Looking at the layout and operation of the engine it occurs to me that the thing will create tremendous vibration unless another pair of cylinders is added and the two pistons operate 180 degrees out of phase. This would seem to require a mechanical linkage between the two pistons.

[ohanian]

This type of engine has very high efficiency, up to 80% energy contained in hydrocarbon or hydrogen fuel is transformed into electricity. This should lead to cars that 4x outperform current cars in terms of hydrocarbon energy -> work efficiency.

This is a bit misleading.

The normal petrol car engine is about

18% efficiency ( 0.18 )

Assuming they meant 180% improvement in efficiency. We have:

0.18 * 1.80 = 0.324 or 32.4% efficiency

Which is pretty bloody good in my eyes.

So a normal 7 litres per 100 km car would turn into a
3.8 litres per 100 km car merely by using this engine.

[ohanian]

Looking at the layout and operation of the engine it occurs to me that the thing will create tremendous vibration unless another pair of cylinders is added and the two pistons operate 180 degrees out of phase. This would seem to require a mechanical linkage between the two pistons.

You do not need mechanical linkage. Just line them up like this



A===B C===D

-------------------------------------------------------------------

X===B C===X (where X denotes combustion)

-------------------------------------------------------------------

A===X X===D (where X denotes combustion)

[Syeer]

On top of the the fact that the design looks like it might produce horrendous amounts of vibration, and its a 2-cycle (although it appears to be a direct injection 2-cycle, which is, I believe, about on par with a 4-cycle in efficiency and emmisions), I'm curious as to how well those permanent magnets hold up under all the heat and vibrations. Last I checked PMs don't last long in that sort of environment.

[Licho]

Well system as a whole unit should not produce significant vibration, because piston momentum is absorbed by magnetic fields of coils producing electric current.

Exact type of engines used is not important, important is control system that can keep such 2 engines running without the need to store inertia. This is just an experimental layout. In fact they market it as low-emission engine.
Because it's only producing electricity it can run on optimal speed all most of the time..

And regarding permanent magnets and durability - I guess that you can always moe permanet magnets to non-moving part and coils to moving parts.

Btw, why shouldn't PM last long in vibration environment? Aren't they in your loudspeakers holding fine for years?

[Tanada]

On top of the the fact that the design looks like it might produce horrendous amounts of vibration, and its a 2-cycle (although it appears to be a direct injection 2-cycle, which is, I believe, about on par with a 4-cycle in efficiency and emmisions), I'm curious as to how well those permanent magnets hold up under all the heat and vibrations. Last I checked PMs don't last long in that sort of environment.

Vibration doesn't effect magnets that I am aware of, and as for heat, I wouldn't expect 240 F to be a problem, a lot of magnets suffer that or worse constantly.

[Mesuge]

well, I got my friend to translate the main parts of that linked TV clip and my assumption was basically right that the breakthrough is in the driving electronics..

Also, according to that report most agile or even most agressive prospect customers are from Malaysia in addition to euro based car manufs..

That's kind of interesting since guys from the same asian country just
bought 26% stake in the famous german Loremo AG company which
is planning that ultralight 1.5L/100km car.

Smells like Malaysian top brass is quite worried about the unfolding peak oil..

[Frank]

I've just looked at the animation quickly, but what happens when you have a misfire or fouled spark plug or something? It looks like the piston deal will just keep traveling and smash into the cylinder head! Or am I missing something? Is there any device that will mechanically control piston travel?

I have to question if this approach can be more efficient than using a flywheel, which smoothly converts reciprocating motion into rotary motion.

[Licho]

It won't just smash because it's slowed down by coils that convert it's kinetic energy into electrical
It has just enough energy to compress gas in opposite cylinder. That's what control electronics must dynamically ensure probably by changing load of coil circuits.
Little energy is wasted in whole process..

[Frank]

Thanks for your reply - that helped me understand the concept better.

[jato]

How do the pistons stay lubricated with a direct injection 2-stroke? Normally, in 2-stroke operation, the oil is mixed with the fuel to lubricate the underside of the piston. Splash lubrication wouldn't work since a significant amount of oil would end up migrating to the combustion chamber, burning and exhausting.