another new engine

donahuedc · #1 05-10-2006, 07:15 PM

It never ceases to amaze me what people can come up with. Maybe if they ever get a product, this will be my replacement engine in 2000 hours. I know that there are lots of motorheads here who will also find this interesting.
http://www.scuderigroup.com/index.html

pierre smith · #2 05-11-2006, 09:07 AM

This is incredible technology in that it's so simple! I hope that they have the funding necessary to build the engines.

I firmly believe that both Lycoming and Continental's prices include an awful lot of liability insurance premium. If these folks would copy Trutrak and not get the engine certified and only reserve it for the experimental markets, the price should be held down. The unfortunate dowside to that equation is the very limited market.

rv6ejguy · #3 05-11-2006, 10:21 AM

Hmmm. Interesting. Seems like a lot of input hp goes to pumping those "dead" cylinders. Have to see the results of a running example before I believe the efficiency claims. Firing ATDC would show some useful gains in TE.

szicree · #4 05-11-2006, 10:22 AM

It sounds great on paper, but I think managing the transfer of gas from one cyl to the other is the big challenge. I say build a working prototype and lose all the animation. Then I'll pay attention.

Davepar · #5 05-11-2006, 10:51 AM

Quote:

Originally Posted by rv6ejguy

Seems like a lot of input hp goes to pumping those "dead" cylinders.

Just like the compression cycle uses up hp in a conventional combustion engines. Sounds promising, but I'm with Steve. Managing the flow of hot, super-compressed air will be tricky. Needs less animations and more moving metal. Someone should be able to put one in a go-kart in a weekend.

Dave

szicree · #6 05-11-2006, 10:55 AM

If I understand the animation and descriptions, then unlike a blown engine, this thing relies entirely on the dead cyl to perform compression duties. Now when both of the pistons reach the top, compressed air is allowed to pass from one cyl to the other. Of course this air is only gonna slide over until the pressures in the two cyls are equal (roughly half of what it was before it passed over). Since we need to reach good combustion pressure in the power cyl, isn't the pressure level in the compression cyl gonna have to be mighty high. How do we avoid detonation over there?

This kinda stuff always puzzles me. I mean if it really works, build a little one and run a freakin' lawnmower, go-kart or even a little RC boat or something. How hard would it be for a cnc shop to produce one? I smell vapor-ware.

RVbySDI · #7 05-11-2006, 11:58 AM

Quote:

Originally Posted by szicree

Since we need to reach good combustion pressure in the power cyl, isn't the pressure level in the compression cyl gonna have to be mighty high. How do we avoid detonation over there?

Forgive me if my feeble mind fails to understand everything I am seeing and reading here but I don't think there is any detonation at all in the compression cyl because there is nothing to detonate the gases in that cyl. The check valve and the crossover valve prevent the ignited mixture in the power cyl from escaping back through the crossover passage into the compression cyl. Unless detonation is occurring because of the overall radiative heat of the surrounding environment (Seems like that would take an awful lot of heat. But then again I am not an engineer so do not know what the thermodynamic characteristics of a compressed gasoline and air mixture would be.) I don't see what could provide the spark for detonation in the compression cyl?

If my thinking on this is all washed up I would appreciate it if someone would please correct it for me so I don't drown in my own ignorance.

RVBYSDI
Steve

rv6ejguy · #8 05-11-2006, 01:14 PM

Quote:

Originally Posted by szicree

This kinda stuff always puzzles me. I mean if it really works, build a little one and run a freakin' lawnmower, go-kart or even a little RC boat or something. How hard would it be for a cnc shop to produce one? I smell vapor-ware.

I'm with you on that one. My CNC guy could build a 2 cyl example easily in 30 days for maybe $15-$20K.

On a conventional 4 stroke Otto cycle engine, the compression stroke is a prelude to the power stroke. A turbo is a way more efficient way to pump large volumes of air than a piston pump integral with the rest of the hot engine parts.

I wish them well, but they have to have a running example if they want to make it happen.

szicree · #9 05-11-2006, 01:21 PM

Quote:

Originally Posted by RVbySDI

I don't think there is any detonation at all in the compression cyl because there is nothing to detonate the gases in that cyl.

If you put enough pressure on the fuel air mix, just about anything will touch it off. Preignition occurs all the time from heat retained in spark plugs, carbon deposits, burrs on combustion chamber surfaces, etc.

I'm not saying this will be a problem, but gremlins like this are hard to foresee. As my mom used to say "the proof is in the pudding". Mmm, pudding.

gmcjetpilot · #10 05-11-2006, 02:12 PM

I listened to the Video very closly:

"billions spent in development" - Ouch
"it has the potential" - That tells me what?; Is it like when a teacher tells the parents "little jimmy has potential".
"too good to be true" - they even say it, lol ha ha ha
"it is being refined....before working prototype is developed" - Paper engine
"strategic patent portfolio" - this is the sales pitch to get people to buy into it and buy a license.

Based on my very tired understanding of the Otto cycle and thermodynamics it looks like the principal is using the "slave piston" to act as an air compressor. I would say supercharger but it does not seem super to me. This also allows the other cylinder's intake and power stroke to be one and the same! So every rotation of the crank is a power stroke verses every 2 rotations as with a 4 stroke.

Right after the exhaust stroke just past TDC the slave injects the power cylinder with a compressed charge, valve closes and than fires almost at the same time. So the intake and power stroke happen at and just past TDC. That Valve between the slave and power cylinder has to move real real fast to do this. On the power stoke the slave is on it's intake. On the power cylinder's exhaust (up) stroke the slave is on the COMPRESION! Hummmm. Interesting.

In a nut shell, one cylinder does power and exhaust, the other is intake and compression. He basically takes one normal 4-stroke cylinder and divides it into two cylinders, each doing two strokes, but simultaneously. It is either brilliant or ridiculous. I think it is complicated. I agree with the other observations. One may question if it will work at all, but the claim it will be 33-42% more efficient seems like a stretch.

I see a big issue with getting transfer valve to open very fast (over a few degrees of crank angle), pass the high pressure gas between cylinders and than close. On a regular engine you have about 180 degrees of crank angle to open and close each valve and than only every other crank rotation (4-stroke). With this set up the valves, intake on the slave cyl, and exhaust on the power cyl are opening every crank rotation. So this will not be a high RPM engine. Any ideas of how it really works, that is my guess and obvious challenge.

Also I am disappointed they don't do any thing with the exhaust, it is just blown out the pipe? What is good about that. That is wasted energy. The only improvement is in theory is higher compression, but than I don't see that really happening either. May be I should get on the ground floor and buy a license to produce this? hummmmm

I am not selling my Lycoming O360A1A just yet. Cheers George