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Old 04-19-2017, 04:27 PM   #91
manolis
 
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Hello.


Regarding the spark advance and the combustion duration in the PatRoVa rotary valve:


QUOTE from http://home.people.net.au/~mrbdesign...utoTechBRV.pdf about the Bishop rotary valve engine:

“This oblique flow through the window is responsible for one of the rotary valves most useful attributes - its strong in-cylinder tumble flow. The tumble ratio on engines with near square bore/stroke ratios is typically twice that reported for similar 4 valve engines. Unlike the poppet valve this high tumble flow is generated without any loss of volumetric efficiency (VE) and is responsible for very fast burn rates observed. Production based engines built in the early 1990’s had ignition timing of 15, or less than half that of the best four valve engines.”

End of QUOTE


In the PatRoVa the combustion chamber (i.e. the cavity at the “top” of the cylinder head) is substantially more compact and more fatty and more concentrated around the spark plug than the combustion chamber of the Bishop rotary valve.

The high tumble flow in the PatRoVa remains strong even at the end of the compression (piston at the TDC) because of the shape of the cavity.

These characteristics make the required spark advance substantially shorter than in a Cross-Bishop rotary valve engine (and a few times shorter than in the best 4-valve engines), and the combustion ends shortly after the TDC.


For comparison with a high-tech poppet valve engine:

Think of the combustion chamber of the Ducati Panigale 1299 (116mm bore, 60.8mm stroke, 12.6:1 compression ratio (i.e. mean “height” of the combustion chamber when the piston is at the TDC: 4.5mm)) which is like a coin with abnormal top and bottom surfaces (valves, valve pockets etc).

The flame in the Panigale 1299 propagates in two only dimensions, while in the PatRoVa the flame propagates in all three dimensions.

The flame in the Panigale has to travel twice the distance it travels in the PatRoVa.

The stronger tumble, swirl and turbulence in the PatRoVa force a substantially faster flame propagation.



With the combustion completed substantially earlier in the PatRoVa Panigale, the actual expansion ratio is substantially bigger, the fuel efficiency is better, the exhaust gas temperature is lower and the power output is higher.

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Manolis Pattakos


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Old 04-20-2017, 09:24 AM   #92
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Quote:
Originally Posted by manolis View Post
The flame in the Panigale 1299 propagates in two only dimensions
Think that through and get back to me once you understand what you've said there and it's implications for Physics as we know it.


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Old 04-21-2017, 07:25 AM   #93
manolis
 
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Hello.



Thanks
Manolis Pattakos
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Old 04-21-2017, 09:50 AM   #94
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A one dimensional figure is a line with only length, not a tube, a two dimensional figure is a plane with no thickness, not a cylinder, a two dimensional combustion chamber, among other things, would give you an infinite compression ratio,
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Nick
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Old 04-21-2017, 11:06 AM   #95
manolis
 
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Hello all.


The following drawings show a 2-stroke Flat-Head PatRoVa:













The last animation is stereoscopic (more on how to see stereoscopically at http://www.pattakon.com/pattakonStereoscopy.htm )

The piston is shown in the BDC (bore 116mm, stroke 60.8mm, i.e. as in the 4-stroke Desmo Ducati Panigale 1299)

The blue rotary valve spins at half crankshaft speed.

There are two exhaust ports on the ceiling of the combustion chamber, and two “cuts” on the rotary valve.

The passageway around the hole for the spark plug (at the centre of the cylinder head) provides “pressure” at the top of the rotary valve, so that the rotary valve can spin without friction (the flow of the exhaust gas happens only through the bottom side of the rotary valve).


If the exhaust ports at the top of the combustion chamber seem not big enough, then a different version can be used wherein the rotary valve rotates at crankshaft speed and serves two neighboring cylinders (twin even firing 2-stroke), with the rotation axis (or the shaft) of the unique big-diameter rotary valve being between the two cylinders; in such a case, the area of the exhaust port on the ceiling of the combustion chamber can be as big as the piston area.

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Old 05-17-2017, 07:31 AM   #96
dkwflight
 
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Default Interesting concept.

HI
I wonder about sealing and the changes from heat.
I suppose with careful choice of materials the dimension changes due to temperature rise would be minimal.
Still what about sealing?
If the valve leaks by the engine might have trouble idling.
Starting may need high speeds to initiate combustion.
Good luck with the development of this engine
Dennis
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Old 05-25-2017, 05:21 AM   #97
manolis
 
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Hello Dennis and thanks.

The sealing is based on keeping the clearances too small, preferably without sealing means (which require lubrication, consume energy, etc).

The question turns to whether the PatRoVa design can keep the clearances as small as required.


The form of the PatRoVa rotary valve (a short and extremely stiff hub / shaft having two disks secured at its ends),



the loading of the PatRoVa rotary valve from the high pressure gas (which eliminates the total force acting on the valve and on its bearings),

its unconventional architecture according which:
only the one dimension relates with the sealing clearances (the other two dimensions are insignificant for the sealing efficiency),
the combustion chamber has uniform temperature (because every point of it relates equaly with the intake and the exhaust),
the width of the combustion chamber is small (keeping small the thermal expansion),
the limited angle (some 90 degrees) around the rotary valve wherein a tiny clearance between the disks of the rotary valve and the ports of the combustion chamber is required,

etc,

allow (and, more important, can maintain during the operation) the required tiny clearances.

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Old 05-25-2017, 05:22 AM   #98
manolis
 
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Hello all.

According an Issue Notice of the US Patent and Trademark Office:



a patent is granted for the PatRoVa Rotary Valve.

The patent number is US9,677,434.

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Old 05-25-2017, 04:24 PM   #99
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Quote:
Originally Posted by dkwflight View Post
Still what about sealing?
It will work fine dry if the tolerances are tight enough, the down side is that a system with such tight tolerances will not be tolerant of any contaminants and, like Ducati engines, will eat itself in an interesting way at an unpredictable point ;-)


The patent is a great (but expensive to enforce) protection against the hordes wanting to use your design without paying

- Nick
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Old 06-13-2017, 03:11 PM   #100
manolis
 
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Hello all.

Today the US-PTO published the USA patent granted for the PatRoVa rotary valve.

Here is the link:

http://patft.uspto.gov/netacgi/nph-P...&RS=PN/9677434

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