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A "new" kind of lightweight/low multi-fuel recip engine.

A "new" kind of lightweight/low multi-fuel recip engine.

A "new" kind of lightweight/low multi-fuel recip engine.

(OP)
Guys...

Fascinating new recip engine design/arrangement from a company in New Zealand:  http://www.dukeengines.com/

Note. I can't help compare this engine to the wankel.

Your comments?

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

RE: A "new" kind of lightweight/low multi-fuel recip engine.

(OP)
....and this one also [also from the Kiwi's]:  http://www.pivotalengine.com/

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

RE: A "new" kind of lightweight/low multi-fuel recip engine.

The Pivotal engine seems to be a topological transformation of a reed valve piston port two stroke.  I don't doubt that it can be done, but I'm not seeing the advantages.

The Duke engine is actually new, mostly, comprising a five cylinder barrel engine running against a fixed cylinder head with three plugs and sets of valves, with the usual barrel cam replaced by a swashplate and a single crank.  I see the 'head gasket' function as critical, and probably the Achilles heel, because of the sliding motion involved.  Also, the necessity of pocketing the valves limits the compression ratio, and makes me wonder about meeting emission regs.



 

Mike Halloran
Pembroke Pines, FL, USA

RE: A "new" kind of lightweight/low multi-fuel recip engine.

They are talking about 14:1 compression ratios, and the cylinder barrel rotates against a fixed head. The machining tolerances between the fixed & rotating components must be very tight, and the alignment axis very accurate as well. Be interesting to keep an eye on this thing, especially the manufacturing costs.

RE: A "new" kind of lightweight/low multi-fuel recip engine.

Sweeping high pressure seals across exhaust ports and the like is the bete noire of many of these novel engine designs. If someone can solve it happily then many architectures would become feasible. If...

Swash plate engines attract a lot of interest, they look sexy. But there is an inherent ugliness, providing a swashplate bearing surface that can handle a lot of acceleration and combustion force, in both tension and compression.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies  http://eng-tips.com/market.cfm?

RE: A "new" kind of lightweight/low multi-fuel recip engine.

GregLocock,

Your point about the tribological and heat transfer issues involved with the bore face seal in rotary block (cam or swash plate) axial piston engines is well made.  The leading edges of the seal ring and exhaust port get the combined worst case conditions of high gas velocity and high gas temperature, right at EXOP. And since the exhaust port in the head is common for all of the cylinders, that port is subjected to a high number/frequency of exhaust cycles.

In order to get acceptable face seal wear/life and low friction, the face seal to head contact must operate with at least boundary lubrication conditions, similar to piston compression rings.  Getting the oil film control right on the head sealing surface is a challenge, as is the local heat transfer between the seal ring/head/block.  With the engine design I linked in my previous post, I spent a lot of effort on these issues.  I would love to discuss the solution I developed further, but unfortunately I cannot at this time since it is the subject of several provisional patents.

Regards,
Terry

 

RE: A "new" kind of lightweight/low multi-fuel recip engine.

(OP)
Just found the attached article AIAA 98-5597 "Barrel Aircraft Engines: Historical Anomaly or Stymied Innovation?". I guess some things are more "evolutions" than "revolutions"... no matter how the designer beats their own drum.

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

RE: A "new" kind of lightweight/low multi-fuel recip engine.

(OP)
And yet another mind boggling recip engine concept: Two and Four Cylinder Single Stroke Opposed Piston Engines

Comments?

http://www.engineeringtv.com/video/Two-and-Four-Cylinder-Single-St
 

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

RE: A "new" kind of lightweight/low multi-fuel recip engine.

The guy is full of crap.
Nice models.  ... but they are _concept_ models, and don't run.
The two-liter '300 HP' model has parts sized for maybe 20HP.
Lots of 'hopeful engineering' going on there.
I sure hope they can meet their goal of assembling them real fast, because running them is going to disassemble them faster.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: A "new" kind of lightweight/low multi-fuel recip engine.

Have you ever taken apart a variable-displacement piston pump?

Looks pretty much the same inside.  

Steven Fahey, CET

RE: A "new" kind of lightweight/low multi-fuel recip engine.

And there are lots of hydraulic, hydrostatic motors that look similar to that pump. The main difference between the two is the pump swash plate angle is variable. They must be good for that application since they are constantly immersed in oil.

Just because it runs it doesn't mean it will last long.
What are the main cases to be made from?  

RE: A "new" kind of lightweight/low multi-fuel recip engine.

A swash plate AC compressor, such as a Delco, or Harrison, V7, runs for a long time and is a reliable and effective, and fairly cheap, piece of equipment.

BUT

Its working fluid is cold and non oxidising , and has a lot of oil dissolved in it.

Undoubtedly one can build an IC swash plate engine, they are powerful, smooth, and clever. But they are designed with a life of the order of hours.

 

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies  http://eng-tips.com/market.cfm?

RE: A "new" kind of lightweight/low multi-fuel recip engine.

A bit OT, but the coolest application of a swash plate pump has to be the Space Shuttle's hydraulic APU.  It uses hydrazine fuel to drive an axial turbine at around 70,000 rpm, which then drives the swash plate hydraulic piston pump through a reduction gearbox.  Around 140 hp and 88 lbs.  The APU provides variable hydraulic flow based on demand.  The hydraulic APU is necessary because the shuttle flies unpowered during landing.

And for you environmentalists, the exhaust emissions from the APU are carbon-free!

RE: A "new" kind of lightweight/low multi-fuel recip engine.

Reminds me of a lot of cleaver ideas I have seen. For example, this one is interesting:
http://www.aqpl43.dsl.pipex.com/MUSEUM/POWER/tower/tower.htm
(along with others on that site)

I looked into the analysis on that as I was interested. It's pretty much identical to that of a Hooke's joint. (minus the thermo-heat transfer regime) Thus, the engine would have repeated-reversed angular acceleration fluctuations.
 

peace
Fe

RE: A "new" kind of lightweight/low multi-fuel recip engine.

Hi!
"In 1911 the Macomber Rotary Engine Company of Los Angeles marketed one of the first axial internal-combustion engines, manufactured by the Avis Engine Company of Allston, Massachusetts."

"Pioneer aviator Charles Francis Walsh flew an aircraft powered by a Macomber engine in May 1911, the "Walsh Silver Dart"."


Extracted from http://en.wikipedia.org/wiki/Swashplate_engine

1911 !!!....amazing!

Cheers

RE: A "new" kind of lightweight/low multi-fuel recip engine.

Steven,
I agree. Very neat. Although, at first glance it appears that the inertial forces under operation may cause problems for that particular idea (along with others on that site)

cheers

peace
Fe

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