Rotating Liner Engine

[Arneal]

I figure you guys might be interested in this. The concept is similiar to a sleeve valve, but does not involve gas exchange. The rotation is used to decrease friction and thus reduce wear and increase gas mileage. Why someone in Texas is interested in fuel mileage is a mystery, but it makes a good read.


www.utexas.edu/ogs/public/dardalis.html

http://www.utexas.edu/admin/opa/onca...6/oc_fuel.html

[pabs]

hehehehe. Well I go to UT and I can tell you that our ME dept. has quite a bit of research to develop this type of systems. THey do a lot of combustion work.

[bobdar]

I don't get it. Do the piston rings rotate with the liner, therefore "spin" in the ring grooves? How does this reduce friction?

[yelwoci]

naturally there's no mechanical friction losses in this setup!

[Arneal]

I do not believe that the piston rings rotate with the liner. Friction is reduced because the rotating liner distributes oil more evenly and consistently.

[RWC]

Hmmm.I looked at the pics & read the words and....didn't understand it either!Is the friction reduction entirely down to better oil distribution?Surely there are better ways to fix that!one would think...

[THR]

imagine you have a hole
and a pin that is a good fit in it.

if you push the pin in the hole its hard. and wont go in, cos there is tooo much friction, and its a tiny bit big.
if you twist and turn, it does become easier. im sure most of you have found this in real life!

think this is the principal it works on, as piston rings are a good fit, so if you turn them it would reduce the friction.

[bobdar]

Well, I never pass up a chance to beat a dead horse. Rotating the rings relative to the liner would overcome the "breakaway" friction, but add to the total energy required (to overcome friction) by adding the rotational movement to the linear motion. More total movement of the ring relative to the liner = more work = more energy lost. Not to mention that the rings will rotate in the ring grooves unless they are pinned, and it seems that the rings/pins would be constantly battered. Is this concept for real, or did it work on the sleeve valve engine simply because the valvetrain losses were eliminated??

[RWC]

Ahh i've got it now.Also like trying to push a hose onto a fitting.Turning it makes it easier.Can any one explain the physics of it?

[bobdar]

When trying to get something to slide on something else, you mustfirst overcome the "breakaway friction", which usually is greater than the friction associated with sliding. So, there is some potential for this to work, as the liner is always in some motion relative to the rings. I still have my doubts, though.

[RWC]

i was thinking is there any other way to provide movement at the ring/liner interface but this seems the 'simplest'way to do it.In my opinion i don't think any manufacturer will take up the idea.not when they are making great strides in friction reducing surface finishes.

[UAV]

Having Harry Ricardo's book High Speed Internal Combustion Engine (5th edition), He explains quite a lot on sleeve valve engines which include motoring friction in the experimental single cylinder in which he had developed. He notes that the motoring friction at 1300 rpm was about 2lbs/in. B.M.E.P. which was A bit lower than the poppet valve engine (same size and bore/stroke). He attributes it to quite a few things including uniform angular velocity, ideal for fluid lubrication, reduction of velocity by 1/2 because of the sleeve 'traveling with the piston, (friction goes up roughly the squared of the speed-non linear).

[hugo]

The concept does not reduce wear but spreads out over the totall surface off the liner.normally the liner will have an oval shape due to wear between liner and piston.because of the fixed position of both.with a rotating liner you have a long term benefit,i.e. for marine engine's.One manufacterer even has an rotating piston crown,for less stress in the piston crown and better cooling.
In f1 Collin Chapman once said a good f1 car should fall apart after the finish.don't think this will catch on...

[UAV]

One thing I forgot to add about the sleeve engine is that at no time was the piston stopped in relation to the sleeve, thus boundry layer is always present. I have seen marine engines, I think only as a bulge pump that are sleeve, that have over 20,000 hours on them. Mind you, they are constant speed engines with a low load on it. Also the Bristal Hercules radial engine has the longest TBO of any aero piston engine that I seen - 7500 hours. But this sleeve engine from U of Texas seems to only rotate along the center line and does't seem to translate up and down. So the boundry layer would still diminish as compared to the normal sleeve valve at TDC and BDC. By the way both in Ricardo's book and in J.L.Setwrights book on aircraft engines,
Napier Sabre had the highest power to weight ratio, and the highest power. It's rating was 3450 hp, and they had an experimental power unit with 5000hp @ 4200 rpm. It ran at 5000hp for over 100 hours on the dyno. Ricardo experimented with extremely high supercharging of a sleeve engine (2 stroke) with a bmep of 354 x 2 (2 stroke remember)before the war even broke out. F1 got to that point midway though the turbo era, just to make comparisons. And finally Napier also make a inverted v12 2 stroke compresion ignition (diesel) aero engine design for airlines. The weight to power ratio was stated as .71 and the specific fuel consumption was .295 hp/lh/hr. Still one of the lowest
S.P.F.outside of ceramic engines. Unfortunately, the jet era came about, with cheap jet fuel and faster speeds. As you can see I did a lot of research on the sleeve engine, And I think it still has viability today. One problem it does have is a somewhat limited port opening duration compared to poppet valve. So in high rev, non turbo charge engines it may not be so good. It is also noted that the British Government ordered that sleeve valve engined aircraft would never be used outside the British territory to prevent it from falling into the enimies hands. Or at least the story goes. There was much animosity between Napier and Rolls Royce.