New engine design?

[wolram]

http://www.sciencedaily.com/releases/2008/09/080915164550.htm

ScienceDaily (Sep. 15, 2008) — In an advance toward introduction of an amazing new kind of internal combustion engine, researchers in China are reporting development and use of a new and more accurate computer model to assess performance of the so-called free-piston linear alternator (FPLA).

[Topher925]

Wow, thats gotta be a systems engineers nightmare! Getting all the porting timing down and being able to evaluate huge amounts of sensor data real time like that, better them than me. It doesn't really look like anything special though. The IC engine is pretty close to perfected. The only useful research being done these days is the HCCI engine.

[mgb_phys]

It doesn't really look like anything special though.
Might be useful for small light engines, especially in hybrids - no crankshaft or gearbox.

Especially clever if you can use the alternator as a solenoid so no need for a starter motor.

[chhitiz]

The only useful research being done these days is the HCCI engine.
i looked up hcci engines and i have a doubt. how come the mixture doesn't auto ignite at say, c.r. of 16 when the mixture is being compressed to 20:1 or 21:1

[Mech_Engineer]

The inherent fact that it is a two-stroke engine also means the engine would have significantly worse emissions than a four-stroke engine.

[mgb_phys]

The inherent fact that it is a two-stroke engine also means the engine would have significantly worse emissions than a four-stroke engine.
Is that necessarily true - or does it just apply to nasty little 2strokes that use lubricating oil in the fuel?
Industrial diesel engines are 2 stroke because it is the most efficent, I would have thought that to get the best efficency you need to burn the fuel most completely and so produce less polution.

[Topher925]

i looked up hcci engines and i have a doubt. how come the mixture doesn't auto ignite at say, c.r. of 16 when the mixture is being compressed to 20:1 or 21:1

Did you look up what the acronym HCCI stand for?

2-stroke engines will always be less efficient than 4-strokes in most applications. The only thing that makes them more efficient is that they can be made significantly lighter than four strokes which would increase fuel economy due to weight which can be very important in something like a UAV.

[OmCheeto]

The inherent fact that it is a two-stroke engine also means the engine would have significantly worse emissions than a four-stroke engine.

I know that was true in the past. But what of the new fuel injected, high tech two-strokes?
http://findarticles.com/p/articles/mi_m0KJI/is_6_115/ai_103990207
Right now, the engine is clean enough to pass California's 2008 standards.

And as far as the FPLA goes, it strikes me that it still suffers from the problem of loss of energy due to the constant changing of direction of the pistons. If people want a "one moving part" efficient engine, why not build a mini gas-steam combined cycle single shaft turbo generator?

[RonL]

That would be just too easy to transform into a steam driven system:cool:

Good clean power:smile:

[RonL]

I know that was true in the past. But what of the new fuel injected, high tech two-strokes?


And as far as the FPLA goes, it strikes me that it still suffers from the problem of loss of energy due to the constant changing of direction of the pistons. If people want a "one moving part" efficient engine, why not build a mini gas-steam combined cycle single shaft turbo generator?

You posted while I was looking.

I'm not sure the gas is needed, but I need to be careful and protect my $75.00 special :wink:

Ron

[mshinavar]

Did you look up what the acronym HCCI stand for?

2-stroke engines will always be less efficient than 4-strokes in most applications. The only thing that makes them more efficient is that they can be made significantly lighter than four strokes which would increase fuel economy due to weight which can be very important in something like a UAV.

because they are so stubborn and unreliable, no person would ever step into an airplane with a 2-stroke powerplant...lol

[russ_watters]

Wow, thats gotta be a systems engineers nightmare! A mechanical engineer's nightmare too - if they ever build one, they'll want to put a picture of it next to the word "vibration" in the dictionary.

[glondor]

Re: vibration, what if it was a 2 shaft 4 piston unit with the shafts at 180 degrees out of phase? would they sort of cancel each other out?