6-Stroke Isovolumetric Engine

[silverbulletAWD]

Interesting concept I thought. Not brand new, but interesting none the less.

http://www.ducati.com/bikes/techcafe.jhtml?detail=article&value=theory&part=general&artID=11

 

[graf703]

Do you think the floating piston would work? maybe with chromed cylinder walls...
You should look up smokey yunick (sp?) he had some crazy engine ideas that actually worked.

 

[WombatTSi]

saw that about 2-3 years ago, and actually wrote a paper on it 2 quarters ago. Without going into it too much, its a very interesting idea, but your only effecting efficiency (as measured by consumption vs output, not loss of power to heat, as this is not really effected at all by the 6 stroke setup) overall by 5-7%. Granded thats a big margin, but probably not big enough to warrent the R&D into a practical application. The one place where it first seems practical is being used in Motorcycles (weird, being that ducati developed it ) where effeciency is key. However this causes another problem, a motorcycle typically will rev to 12-16k RPM to make the most of its low tq, low displacment motor; unless that piston is going to be REALLY heavy (I can't remember the exact weight I calculated, but something close to 1.5kg) at 14k RPM you're going to essentially "float" the piston l(ike you do a valve) between the forced exhaust and intake strokes. This added weight would more than offset any gains you would see via a LOT of piston Inertia. So yeah, while its a pretty cool idea, its just not that practical as it sits. Much more practical advances can be found with cam-less, and/or valve-less valve train setups IMO.

 

[Defiant]

You should look up smokey yunick (sp?) he had some crazy engine ideas that actually worked.

Smokey was to engines as Kelly Johnson was to aircraft.

Some people just aren't from around here.

Earth, that is.

 

[graf703]

but he did have one that worked!!! what was it... two cylinders, 45 mpg 200 horses or something

 

[silverbulletAWD]

saw that about 2-3 years ago, and actually wrote a paper on it 2 quarters ago. Without going into it too much, its a very interesting idea, but your only effecting efficiency (as measured by consumption vs output, not loss of power to heat, as this is not really effected at all by the 6 stroke setup) overall by 5-7%. Granded thats a big margin, but probably not big enough to warrent the R&D into a practical application. The one place where it first seems practical is being used in Motorcycles (weird, being that ducati developed it ) where effeciency is key. However this causes another problem, a motorcycle typically will rev to 12-16k RPM to make the most of its low tq, low displacment motor; unless that piston is going to be REALLY heavy (I can't remember the exact weight I calculated, but something close to 1.5kg) at 14k RPM you're going to essentially "float" the piston l(ike you do a valve) between the forced exhaust and intake strokes. This added weight would more than offset any gains you would see via a LOT of piston Inertia. So yeah, while its a pretty cool idea, its just not that practical as it sits. Much more practical advances can be found with cam-less, and/or valve-less valve train setups IMO.

I think you pretty much stated my opinion for me . But like I said, just thought it was interesting and maybe some of these guys might think the same. It's good to excercise the brain with "outside-of-the-box" thinking every once and a while .

Andy

 

[MNGSX]

Look at what desmo means on ducati engines.. Desmodromic (sp) valves. NO VALVE SPRINGS! They all have this system and have had it for a while.. One rocker lifts and the other lowers. They move in unison.

Ducati just might build that engine..

 

[FireyIce01]

Look at what desmo means on ducati engines.. Desmodromic (sp) valves. NO VALVE SPRINGS! They all have this system and have had it for a while.. One rocker lifts and the other lowers. They move in unison.

Ducati just might build that engine..

And if I had the cash I would have my machine shop make a desmo head for my car... but I have sooo many want/needs.... now if someone were feeling really savvy and could get ahold of a MIVEC head, and a desmo setup, and make a desmodronic MIVEC that I can bolt on a 4g64 with a big ass turbo... then I'll be happy

 

[GSX_RCR]

And if I had the cash I would have my machine shop make a desmo head for my car... but I have sooo many want/needs.... now if someone were feeling really savvy and could get ahold of a MIVEC head, and a desmo setup, and make a desmodronic MIVEC that I can bolt on a 4g64 with a big ass turbo... then I'll be happy

Do you want fries with that too? :laugh:

 

[graf703]

I assume you're just showing off your vocabulary... what the hell is all that stuff?

 

[saw wave analog]

its not the size of the vocabulary, its how you use it

 

[MNGSX]

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http://www.ducatitech.com/info/desmo.html

 

[NDgsx]

The desmodromic valvetrain has been around for a long time. It has been deemed to troublesome for standard prodcution due to the constant adjustments that normally need to be performed and the increased production costs due to the increased complexity.

There was a good article about it in the last engine masters.

 

[Defiant]

Screw camshafts. Time for hydralic or pneumatic. At least some F1 stuff has gone to pneumatic springs.

 

[Jehu]

It's still a 4 stroke...A stroke is the linear movement of the piston in the cylinder...A stationary piston is NOT stroking...