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cowpoos
26th June 2009, 17:17
Wadddya guys think of this http://www.pivotalengine.com/flashversion.html


It really looks just like a new way to get power with two cycles,without alot of benifit??

Taz
26th June 2009, 17:24
Just looks more complicated than using a piston. What are the percieved advantages?

p.dath
26th June 2009, 17:35
It looks to me like only a small portion is under power on the down stroke, and then the exhaust port is reached, throwing away any power that may be left. And there looks like a lot of overlap between the inlet and exhaust port.

My guess is this engine would be really inefficient.

Skunk
26th June 2009, 17:43
Clean burning two stroke-ish power is the advantage. The engine is injected so (in theory) there is no unburned fuel going down the exhaust.

Ocean1
26th June 2009, 17:50
Timing looks not dissimillar to a typical 2X. On this one, though the intake volume is greater than the swept combustion volume, it’s effectively supercharged.

Seen a couple with similar design intent. What they don't show here, and what's the achilles heel of most arrangements like this is the seal details, especially the (non-radial) side seals.

bogan
26th June 2009, 18:07
machining that bore would be a bit of a challenge, and i agree, what are the advantages over a standard two stroke, direct injection of course, but the pivot design doesnt seem help with that. The more common two stroke supercharged deisle engine seems far better.

Also, i find this one interesting The Rotoblock (http://www.rotoblock.com/howitworks.shtml)

Ocean1
26th June 2009, 18:18
Also, i find this one interesting The Rotoblock (http://www.rotoblock.com/howitworks.shtml)

Not new, but I haven't seen quite that linkage setup before. Very cute, slow though, double the piston surface speed.

What do we think of this, then: http://kugelmotor.peraves.ch/index_en.htm

bogan
26th June 2009, 19:15
What do we think of this, then: http://kugelmotor.peraves.ch/index_en.htm

hmmm, thats pretty cool actually, sealing the compression bits cud be difficult though.

erik
26th June 2009, 19:36
I don't get excited about "new" engine designs. I reckon the standard piston engine configuration must be the optimal configuration, all the new engine designs I've seen have been more complicated and look like they'd be difficult to produce. Improvements come from refining the existing designs, not from thinking up some weird new design.
That's my opinion, maybe I'm too cynical.

tychver
28th June 2009, 21:19
I don't get excited about "new" engine designs. I reckon the standard piston engine configuration must be the optimal configuration, all the new engine designs I've seen have been more complicated and look like they'd be difficult to produce. Improvements come from refining the existing designs, not from thinking up some weird new design.
That's my opinion, maybe I'm too cynical.

Some, like the wankel, are simpler in construction. We're just too far down the path with the conventional 4 stroke piston engine now.

sAsLEX
28th June 2009, 21:38
I don't get excited about "new" engine designs. I reckon the standard piston engine configuration must be the optimal configuration, all the new engine designs I've seen have been more complicated and look like they'd be difficult to produce. Improvements come from refining the existing designs, not from thinking up some weird new design.
That's my opinion, maybe I'm too cynical.

Where would we be if engineers thought like that before the steam engine?? Or then the diesel? etc

another idea http://auto.howstuffworks.com/quasiturbine1.htm

Dare
3rd July 2009, 18:22
I don't get excited about "new" engine designs. I reckon the standard piston engine configuration must be the optimal configuration, all the new engine designs I've seen have been more complicated and look like they'd be difficult to produce. Improvements come from refining the existing designs, not from thinking up some weird new design.
That's my opinion, maybe I'm too cynical.

That's old person talk, many great inventions go through an 'early adopter' phase. This phase is where the technology is expensive and unreliable, then if the idea is good things start to improve. Early motorvehicles had nothing over horses and carts.

That superballmotor has three moving parts, not exactly insane considering the huge list of things added to petrol engines over the years. DOHC, superchargers, turbos, EFI, 4 valves per cylinder, etc, etc.

Having played with CAD and rapid prototyping machines, and getting all excited about 5-axis milling machines, concept to prototype is now worth the effort. Bikes however have all the power to weight they need IMO, its just efficiency and simplicity (hence reliability) that needs improving.

Also, if battery tech improves sooner rather than later then its possible that electric bikes could kick carbon fuels ass. After all the only parts to wear in an electric motor are (broadly speaking) the bearings. I'd prefer it if they made a sweet noise though!

mouldy
4th July 2009, 14:02
No better than a 2 stroke and more bits to wear out , noones built a better motor then piston engines for cars and bikes yet , many have tried .

Madness
5th July 2009, 20:13
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Ceeyrmn2Pj4&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowScriptAccess" value="always"></param><embed src="http://www.youtube.com/v/Ceeyrmn2Pj4&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="425" height="344"></embed></object>
Hallelujah.

Pixie
8th July 2009, 09:07
It looks to me like only a small portion is under power on the down stroke, and then the exhaust port is reached, throwing away any power that may be left. And there looks like a lot of overlap between the inlet and exhaust port.

My guess is this engine would be really inefficient.

You're looking at an animation,KnobHead,I doubt you can accurately derive the port timing from it.

The advantage of the Pivotal Engine is that the piston is precisely constrained by the pivot bearings,instead of flapping around like a conventional piston does.
The piston is also watercooled,which makes it ideal for hydrogen fuel.

Madmax
22nd July 2009, 22:19
some good ones

Madmax
22nd July 2009, 22:38
some more for you all

ducatilover
22nd July 2009, 23:53
Many of these wonderful new designs are great ideas, but. The stress of combustion may well overcome the stranger ones sooner than our normal configuration. I can see many a balancing problems, un necessary reciprocating mass, and major wear about to happen. But, they are really choice ideas. I'm not saying one or more of them may better the general layout we are using, but, you never know. People have managed great things with the Wankel engine.

That first example did seem to scavenge alot, as far as I have been taught scavenging through "valve" overlap [not the exact case here] can increase intake velocity. Increased intake velocity can mean more potential combustion and a higher amount of cooling to the intake valve, letting a sharper camshaft face to be used to allow for more duration, smaller lobe centers and more power and hirgher rpms. Ofcourse like everything in an engine there is a compromise.


But, I may be wrong, feel free to correct me:yes:

bogan
23rd July 2009, 09:49
theres certainly a lot of alternative designs out there, but as they all work on the same basic principal, it wouldnt surprise me if they all had very similar power outputs, life-cycles, and efficicncys compared with traditional engines. Some designs may performa and wear like a rotary, some inefficient and powerful as a two stroke, some effecient like one of those fancy deisle.

The real engine improvements are in ceramic coatings and that sorta guff, if they can get those to work good as you cud run an engine with no radiator, and no oil, vastly increaing the temperature, and efficiency, preolly nead direct injection for it though.

Or just go electric, a guy did a 40hp 140kg Apprilia RS125 conversion, does 80mph, and goes 40miles between charges. So its basicaly like my VT250, but better acceleration, and lower range.

Madmax
23rd July 2009, 18:43
seems a bit ahead of its time


Bore 4.25 in
Stroke 5.5 in
Displacement 1404 in3 (23,007 cc)
Output 425 HP at 2000rpm
Weight 749 lb
Diameter 20in

Madmax
23rd July 2009, 18:47
Many of these wonderful new designs are great ideas, but. The stress of combustion may well overcome the stranger ones sooner than our normal configuration. I can see many a balancing problems, un necessary reciprocating mass, and major wear about to happen. But, they are really choice ideas. I'm not saying one or more of them may better the general layout we are using, but, you never know. People have managed great things with the Wankel engine.

That first example did seem to scavenge alot, as far as I have been taught scavenging through "valve" overlap [not the exact case here] can increase intake velocity. Increased intake velocity can mean more potential combustion and a higher amount of cooling to the intake valve, letting a sharper camshaft face to be used to allow for more duration, smaller lobe centers and more power and hirgher rpms. Ofcourse like everything in an engine there is a compromise.


But, I may be wrong, feel free to correct me:yes:

these are all about 1930 or before there is not much
that has not been done before
:crazy:

ducatilover
23rd July 2009, 19:53
these are all about 1930 or before there is not much
that has not been done before
:crazy:
Too right, engine design is all about compromise. Which is why valve timing, lift and duration systems were made. The same reason ignition advance/retard was made. The same reason we buy the wife what she wants [but buy it cheap, no car, no head]:innocent:

Pedrostt500
23rd July 2009, 20:13
Try this one,
http://www.bourke-engine.com/
There is some interesting history to this one.

Pedrostt500
23rd July 2009, 20:44
I would acyualy like to see a Bourke engine in the flesh, keep in mind he desighned this engine in the 1930s, back then to get 20,000 rpm from a piston engine was un heard of, he could not get higher RPM due to no ignition system of the era was capble.
There was a story that I read years ago that said they were testing the engine in a Ford V8, they were driving at 40mph when Russel Bourke told his test driver to suddenly floor the accelorator to see what would happen, apparently the gear box decided to let go.

ducatilover
23rd July 2009, 21:06
They are unbelievable, especially when you consider the era.
Reminding me of ahead of time, many BRM engines were amazing but suffered from ignition problems.

Madmax
14th August 2009, 17:43
forgot one

ducatilover
14th August 2009, 20:13
Now, that, is an interesting idea!

Madmax
15th August 2009, 22:06
one more for the interested