2 stroke thread (with occasional F1 relevance!)

[Muniix]

Hello Muniix

I have spent several hours reading the patents granted (or filed but not granted) to the guys of the multi-million Bishop team.

I admit I failed to understand the way the sealing means of the Bishop rotary valve are lubricated: just like the piston rings of the conventional 2-strokes they pass over big holes (the intake and exhaust ports on the Cross-Bishop rotary valve), yet they don’t leave any lubricant to get into the combustion chamber or to be lost towards the exhaust.
As explained in previous posts, the theories about the “dry lubrication with the carbon particles of the combustion” are not persuasive.

Those detail are not in the patents, but be sure that the rotron also sealing without added lubrication may not be a coincedence! They had a harder job creating the correct species needed by controlling the environment. When one understands chemistry, combustion and fluid flows it is obvious.

I also admit that I still do not get the real difference between the Bishop rotary valve and the original Cross rotary valve (or the rotary valve of Ralph Watson).
If anybody in this forum can explain, in simple words, their main difference, it would be great.

Both are rotary valves with different implementations, hence they are identified by the developer.

It was Arthur Bishop and his engineering teams long experience in rotary valves for variable rate power steering optimised to work well from the human brain to the steering action and its effects at the tyre contact patch that allowed him to have success.

Smart people think of the whole system, not just solving one issue, and compromising all the others.

Bishop technology is in 20% of vehicles produced, nascar, f1 ...

It worked and worked well, maybe with the advances made in the last 10-15 years with 3D metal sintering, heat diluted ultralean jet ignition, multiphase combustion, introducing more fuel to burn more of the oxygen giving constant cylinder pressure ... time to give it another blast, power and efficiency per cycle is wild. Steel pistons work fine.

Despite the many millions of dollars (as you like to write / repeat) invested in the Bishop rotary valve project (and the many famous and smart guys involved in the Bishop project), nothing is left.

Nothing at all.

Not one (just one) motorcycle having the Bishop rotary valve on the cylinder head for normal use or for road tests.

Clearly you have no understanding of business, that was explained, go reread my previous post, you can't keep funding something that the returns on have been denied by bans.

Opinions are not facts, and will be treated as such

Maybe your wrong, maybe someone is riding around on a CRF-450 while not technically legal, but damn fast and quiet, no valve chatter! hiding the head with covers increasing the flow to the cooler extracting heat from the valve.
They are as rear as hens teeth, not wanting it to be damanged or stolen, Ian Drysdales 750 V8 motorcycle was stolen recently, with alarms, dogs.

Claiming opinions as facts is mischevious at best. I have learned to avoid doing business with such people, seen too many projects fail due to this behaviour.

You talk about how much it costs to do professional engine development and patents​, business is about making money, costs are part of that process.

How much revenue have you made from your patents in licensing fees?


Marc

[manolis]

Hello J.A.W.

Here is a stereoscopic animation of the 2-stroke PatRoVa FlatHead:



Thanks
Manolis Pattakos

[Muniix]

Hello J.A.W.

Here is a stereoscopic animation of the 2-stroke PatRoVa FlatHead:

http://www.pattakon.com/PatRoVa/PatRoVa ... Head_6.gif

Thanks
Manolis Pattakos

The Tribology on that is going to be a nightmare. Thermal expansion, and sealing, blow-by etc​.

Is going to need high pressure, requiring lots of energy, reducing efficiency.

How can it support direct injection and Jet ignition for the advantages of ultra lean combustion and multi phase combustion where you injection further fuel at max heat release to maintain cylinder pressure as done on the F1 engines with tji. Multi phase combustion when performed effectively increases the Bmep significantly. The ideal Crank angle of maximum heat release is typically 8-14 degrees depending on crank geometry and engine management strategy in regard to the wide fuel equivalence ratio typically 1.4-2.5 times as much air as stoichiometry with no loss of pressure at 1.85. The piston not descended much at that angle, expansion ratio is good to introduce more fuel and maintain cylinder pressure burning more oxygen available from ultra lean operation of tji and the increase of compression ratio tji provides typically 2 points or more.

The power per stroke increasing up to 80% depending on exhaust flow rate, where the Bishop valve excellent flow helps. Normally aspirated Bmep of over 20 bar is easy and highest useful compression ratio 17.3:1 provides high 40s thermodynamic efficiency when not hindered by F1 regulations.

Offset crankshaft provides friction reduction and piston motion advantages, increasing the tdc to bdc duration, and crank rod angle for more effective conversion of pressure to torque with less bearing friction and torsional issues.

Engine management strategies really start to get pretty wild with the versatility available with TJI and DI.

[J.A.W.]

Marc, to be fair..
.. I don't think you need to get too critical about the simply illustrative concept that Manolis
drew up to show how a horizontal application of his rotary valve might function.

Dynamics of flow details are rather more complex, here's some Kevin Cameron considerations..

http://www.dynotechresearch.com/blog/ar ... nYear=2012

& in this one below..
..he discusses the flow processes that have enabled an ostensibly 'primitive' H-D motorcycle engine..
..to gain markedly improved BMEP figures & run a 2T-like ignition advance of 23 degrees BTDC..

http://www.johnsonenginetechnology.com/ ... m-cameron/

[Tommy Cookers]

well isn't that funny (the johnson source linked)
2 pages ago I mentioned (again) the false god of ever-larger valves & ports, and the value to 99% of engines of high dynamic pressure from high gas velocity
I thought to mention the 100000 races won by J.A.P engined speedway machines (J.A.P becoming unbeatable by putting the 350 head on 500s)
and the BMG-devised 500 Velocette that won the 500 class of the 24 hr race at Monjuich Park using a 350 head
and the 70s etc Honda '125' produced from 100 to 223 cc all with the same valve sizes and still in Chinese production today
the 100 being rubbish as the valves and ports were too big (the 185 trials machine had smaller valves)
but then thought - don't bother

and btw re the other link -
don't people know that TE and power will hardly improve by CR increase beyond 11 when using normal or rich mixtures ?
air standard efficiency says this - and there's more dissociation
super high CR can only work with lean mixture

[Muniix]

well isn't that funny (the johnson source linked)
2 pages ago I mentioned (again) the false god of ever-larger valves & ports, and the value to 99% of engines of high dynamic pressure from high gas velocity
I thought to mention the 100000 races won by J.A.P engined speedway machines (J.A.P becoming unbeatable by putting the 350 head on 500s)
and the BMG-devised 500 Velocette that won the 500 class of the 24 hr race at Monjuich Park using a 350 head
and the 70s etc Honda '125' produced from 100 to 223 cc all with the same valve sizes and still in Chinese production today
the 100 being rubbish as the valves and ports were too big (the 185 trials machine had smaller valves)
but then thought - don't bother

and btw re the other link -
don't people know that TE and power will hardly improve by CR increase beyond 11 when using normal or rich mixtures ?
air standard efficiency says this - and there's more dissociation
super high CR can only work with lean mixture

Those articles show the importance of knowing what is going on inside the combustion chamber. With simulation and physics models the best way to inform and exclude bias some humans like confirmed.

Reading them reminded me of the 170 hp Britten V1100/1000 Superbike made by John Britten in New Zealand during the early '90s, he moved the valves toward the centre giving clearance to the liner. His 600 single with 5 valves didn't perform, and they had a 6 valve head. This bike dominated Daytona on debut, Glenn from Falicon was in the next garage prepping their HD said it was real fast.

The ignition advance Bishop team experienced with timing needing to be reduced 0.4 degrees per 1000 rpm as they​ approached max rpm/0.5 Mack intake velocity, combustion speed was scaling faster than engine speed! Simulation revealed greater turbulence just before tdc. Due to air compressibility at higher velocities.

Though how this works with Jet ignition as it provides some of its own turbulence. Surely can't hurt, the feature size of turbulence would have an effect. How many times do you collapse the tumble vortices etc.

I've noted that the fastest rotary at club level racing in Australia is owned by one Tony Wallis, could this be the ex Cosworth engineer who headed up the Bishop valve development & now owns the Bishop patents, I'll have to ask. Would have been easy for him to develop the best seals, makes sense, or is it just coincidence.

Someone asks for comment I gave useful critique, and information. I cherish this when I get it from people I respect. Also for others to assess claims. With 30+ years verifying vendors claims and optimising for purpose, vendors reaction to their products short comings is a good guide for exclusion or inclusion.

Agonising over design decisions like rod length ratio is made far easier with simulation, bearing and piston friction models are now really advanced and take into consideration nearly everything. Now one has to agonize over components all physically fitting together. Is the piston and crankshaft going to collide, if I add an extra mm what will that cost in bearing friction or performance. One can search for the features one wants using automation, simulating 100 configurations. One can cook your laptop with all the physics equations running in the graphics cards GPU, doh! Maybe the power supply died no, battery flat, no. Damn​ that was an excellent laptop I thought, then received a support email on need to keep filter clean!

[manolis]

Hello all.


Muniix wrote:
“The Tribology on that is going to be a nightmare. Thermal expansion, and sealing, blow-by etc.
Is going to need high pressure, requiring lots of energy, reducing efficiency.”


There is a misunderstanding here.

The rotary valve shown is substantially different than an Aspin rotary valve:



or than a Reynolds rotary valve:



In both cases (Aspin and Reynolds) the rotary valve is pressed upwards by the high pressure gas with a few tons of force (for normal size engines).

There is no bearing that can take such extreme forces keeping, at the same time, the required tiny clearances.

QUOTE from Ralph Watson’s article at http://ralphwatson.scienceontheweb.net/rotary.html :

“With great, but what turned out to be misguided enthusiasm, I built a model engine based on the Aspin design, which incorporated a cone type valve the same diameter as the cylinder bore, rotating in the cylinder head. The combustion chamber was contained within the rotary valve, which rotated to line up in turn with the spark plug, exhaust port and inlet port.

Full combustion pressure was applied to the valve, forcing it into the taper of its conical seat with the object of ensuring a good seal, but this arrangement could result in the valve seizing in the head due to lack of clearance and lubrication. In order to counter this, the Aspin design incorporated a roller thrust bearing on the valve stem.

I used the same arrangement but could not attain an adjustment whereby the bearing took the load and a satisfactory seal was achieved. When adjusted so that load was on the bearing, the seal leaked and the engine had poor compression and would not run.
With load on the cone the valve would seize. After suffering much frustration with broken drive shafts and stripped gears, the engine was eventually run for short periods with load on the cone, thanks to a copious supply of castor oil. This was supplied under pressure to the valve face, by means of a hand pump. My goal of fitting the engine into a model hydroplane came to naught and George Bolt and company remained unopposed at the model pond.

However I was able to test the engine running against a brake and it recorded 1/8 h.p. at 8,000 r.p.m., which was a disappointment when related to the figures quoted in the article which had inspired my efforts.

Many years later the story came out that the Aspin engine was tested by the motorcycle manufacturers Velocette, who found that it produced only half the horsepower claimed, the suggestion being that the original testing had been carried out with a wrongly calibrated tachometer.”

End of QUOTE



This drawing



shows / explains how things can operate without friction.

At top left it is shown a shallow trapezoidal “groove” arranged oppositely to the “left” exhaust port (which is cut on the ceiling of the combustion chamber).

This shallow groove communicates, though a “small volume” passageway with the combustion chamber (in the specific case this passageway is formed around the hole / thread wherein the spark plug is bolted).

As the pressure inside the combustion chamber increases, the gas, through the exhaust ports, presses upwards the PatRoVa rotary valve at its bottom side.

However, at the same time, at the top side of the PatRoVa rotary valve it is applied an equal and opposite force due to the high pressure gas in the shallow groove.

This design can eliminate the total “gas pressure force” on the rotary valve, eliminating the frictional force and keeping the “sealing clearances” tiny.


In comparison, a (2-stroke or 4-stroke, it doesn’t matter) Cross – Bishop – Watson rotary valve receives, during the high pressure period of the combustion, an extreme total force and requires big diameter strong bearings and big clearances.

If it is still not clear, I can further explain.




Tommy Cookers wrote:
“don't people know that TE and power will hardly improve by CR increase beyond 11 when using normal or rich mixtures ?”

The Ducati Panigale 1299 Superleggera (priced 81,000 euro!) uses a 13:1 compression ratio.


The F1 Bishop rotary valve engines (2003) ran compression ratios as high as 17:1 using standard F1 fuels before settling on 15.3:1 as optimum. No evidence of knock has ever been observed.


Most Diesels can operate, after the warming up period, at 11:1 compression ratios. However most of them run at 14:1 and higher compression ratios.




Pinger wrote:
“. . . and the work done by Primavis >> http://www.primavis.eu/about point to direction which hasn’t been exploited within the more conventional 2T architecture”


Did you see the PatATi?
http://www.pattakon.com/pattakonPatAT.htm



Isn’t the added complication of the 2-stroke Primavis unnecessary?

Thanks
Manolis Pattakos

[Pinger]

Quote from Manolis: ''
Isn’t the added complication of the 2-stroke Primavis unnecessary?''

Yes. The Primavis configuration is so similar to Clerk's original engine but with different valving, and supercharging courtesy of the higher-than-exhaust port. It is also bulky - which when I think of a range extender application (say), is a serious handicap. The additional friction, unwelcome. The patenting of the 'charge control valve' unless covering only supercharged configuration, kind of blocks anyone using such (rotating at engine speed) to pursue AST though additional functionality is required but not specified in the patent.
My interest lies in minimum departure from the typical piston/rod/crank architecture - to minimise mass, avoid untested sealing arrangements, etc.

Your explanation M of circumventing friction in your horizontal rotary valve. Are you not creating crevice volume - leading to high UBHC? And, denying the spark plug boss the heat path it requires to cool the plug?

[Tommy Cookers]

[quote="Tommy Cookers"]

don't people know that TE and power will hardly improve by CR increase beyond 11 when using normal or rich mixtures ? -air standard efficiency says [/quote]

this is based on importance (to SI engines) of what we could call dynamic CR or even 'thermodynamic' CR - ie raising geometric CR may be meaningless

the other aspect of Johnson's take is port size without mention of valve size - I assume he has in mind port size to atmosphere
it could be argued that port size to atmosphere is dominant ie that valve size whether sufficient or more than sufficient is unimportant
though it could be argued that 'porting (size) to cylinder' is important ie to tuned length effects and kinetic (dynamic pressure) effects
50 years ago Mr McLaren reduced only port size to atmosphere in his F1 destroked-to-3 litre Indy Ford, desperate for some spread of power
105 years ago GP Peugeots needed 5 gears because their ports were made huge (trying to get laminar flow)

and there's the matter of exhaust porting to atmosphere or to some pre-atmosphere high pressure surrogate (re turbo F1 or current F1)

[J.A.W.]

Cracking thread (yes, I read all 93 pages)with some real knowledge and endeavour on display. A couple of points (and questions) on some of what has been discussed. Re sleeve valves (I saw no mention of). Did Ricardo not experience severe scoring of sleeves when the motion was vertical only? No mention either of him ‘knife-edging’ the sleeves’ upper edges (the sealing breakthough IIRC). The ‘knife-edging’ reputedly made the sleeves very vulnerable to damage up to and during assembly...

Uniflow (if you are still looking in) Don’t hold back (as if!)

Pinger, welcome aboard, & as regards sleeve valves, I refer you back to page 5..
.. whereupon Uniflow was presenting a sleeve valve 2T of his making..
..he has this running currently, should you wish to ask him to present it again.. ( via personal message)..

Manolis more recently, has shown graphic representations of his sleeve valve design, too..

In fact, looking at his most recent presentation, the concept could perhaps use a rotary sleeve..
.. & stationary valve-in-head, or indeed, a counter-rotating combination of both...

[Pinger]

Cracking thread (yes, I read all 93 pages)with some real knowledge and endeavour on display. A couple of points (and questions) on some of what has been discussed. Re sleeve valves (I saw no mention of). Did Ricardo not experience severe scoring of sleeves when the motion was vertical only? No mention either of him ‘knife-edging’ the sleeves’ upper edges (the sealing breakthough IIRC). The ‘knife-edging’ reputedly made the sleeves very vulnerable to damage up to and during assembly...

Uniflow (if you are still looking in) Don’t hold back (as if!)

Pinger, welcome aboard,

Cheers!

[/quote]& as regards sleeve valves, I refer you back to page 5..
.. whereupon Uniflow was presenting a sleeve valve 2T of his making..
..he has this running currently, should you wish to ask him to present it again.. ( via personal message)..

Manolis more recently, has shown graphic representations of his sleeve valve design, too..

In fact, looking at his most recent presentation, the concept could perhaps use a rotary sleeve..
.. & stationary valve-in-head, or indeed, a counter-rotating combination of both...
[/quote]

My sleeve valve remarks were more things that Uniflow and Manolis might be interested in as current practitioners of the art and as I didn't see any mention, I thought what Sir Harry learned was worth passing on. From memory, the reason he went to exhausting over the top of the sleeve was because of sleeve failures (popping out a port shaped 'panel') and of course the compactness gained on ditching the junk head was a very welcome bonus.
There is a paper that reports on later investigation into sleeve vs poppet valves and reviews the protagonists' claims. If anyone is interested, I'll try and find it and provide a link.
The asymmetry achievable with sleeves can't be ignored, but for what I'm interested in, a complication too far.
While I remember, also mentioned in the thread was the possibility of deleting piston rings. Some research was done on this by The South West Research Institute. Their angle was free piston engines as gassifiers where high ring wear could be anticipated. Their incomplete conclusions lay out a path obvious to the more imaginative among us... As above, if anyone is interested...

[Muniix]

Hello all.

Muniix wrote:
“The Tribology on that is going to be a nightmare. Thermal expansion, and sealing, blow-by etc.
Is going to need high pressure, requiring lots of energy, reducing efficiency.”

There is a misunderstanding here.

The rotary valve shown is substantially different than an Aspin rotary valve:
< snip >
At top left it is shown a shallow trapezoidal “groove” arranged oppositely to the “left” exhaust port (which is cut on the ceiling of the combustion chamber).

This shallow groove communicates, though a “small volume” passageway with the combustion chamber (in the specific case this passageway is formed around the hole / thread wherein the spark plug is bolted).

As the pressure inside the combustion chamber increases, the gas, through the exhaust ports, presses upwards the PatRoVa rotary valve at its bottom side.

However, at the same time, at the top side of the PatRoVa rotary valve it is applied an equal and opposite force due to the high pressure gas in the shallow groove.

This design can eliminate the total “gas pressure force” on the rotary valve, eliminating the frictional force and keeping the “sealing clearances” tiny.

Using gas pressure via gas ports is never "at the same time" and why this method is never used as the primary means, it is used as a secondary means as it takes some time for the pressure to build up, like charging a capacitor, it also takes time to discharge. One has to control the energy both acoustic and heat to do what is needed. Carbon buildup is possible.

Case in point - piston rings, their tension performs the seal and gas pressure used to assist.

This gas porting increases crevice volume and loss of cylinder pressure, creates additional heat that needs to be managed.

In comparison, a (2-stroke or 4-stroke, it doesn’t matter) Cross – Bishop – Watson rotary valve receives, during the high pressure period of the combustion, an extreme total force and requires big diameter strong bearings and big clearances.

Lucky Strong bearings exist then, hey!
The F1 bishop engine had ultra thin 3mm needle roller bearing of only 15mm width, these worked fine in endurance testing. Even surviving when the 'normal' f1 rods broke when running at MBT ignition timing low 30s btdc due to the fast combustion, fatigue eventually caused the rod to fail, they learned timing needed to be retarded slightly from mbt.

Tommy Cookers wrote:
“don't people know that TE and power will hardly improve by CR increase beyond 11 when using normal or rich mixtures ?”

The Ducati Panigale 1299 Superleggera (priced 81,000 euro!) uses a 13:1 compression ratio.

The F1 Bishop rotary valve engines (2003) ran compression ratios as high as 17:1 using standard F1 fuels before settling on 15.3:1 as optimum. No evidence of knock has ever been observed.

Most Diesels can operate, after the warming up period, at 11:1 compression ratios. However most of them run at 14:1 and higher compression ratios.

What is this even supposed to imply?
Someone picked a number?
Special F1 fuel is special!
Diesel is not gasoline!

Previous combustion implementation ideas are being proven to be bad ideas all time time.

Just because someone does something to form the opinion that it is good is not rational or good science/engineering, one should never copy 'just because', that is how myths and falsehoods propagate, and bad engineering.

Like dual zone combustion areas where the second larger volume communicates through to the prechamber shortly after tdc, rapidly quenching combustion, loosing potential work, has been proven as very difficult to truely be advantageous as made out.

Pre-chambers communicatiing through small passageways are good. Just not large pathways.

A Greater understanding of combustion is important. We are doing more research into combustion now than we have ever before.

Thinking someone should spend large sums of $ a month with no posibility of a return for a very long as the FIM and FIA has banned you is good practice or even possible, without the $ nothing can happen. Someone thinks it can, or hey lets build the full kit to convert a production bike to a BRV, the whole throttle body, cooling, ecu, productise the development crf450 head for another million and wait for orders of 1 or 2 units to come in? who pays the bills? there was no one to pay them.

Why deprive another project, Bishop had the best light rail system and it needed funding. You think this is what one should do.

Dual plugs never work just because, Ducati use the on the 1198 DS and all current Testastretta engines. Because my opinion says so.

Why are some people wrong on all counts. that takes effort

[J.A.W.]

...My sleeve valve remarks were more things that Uniflow and Manolis might be interested in as current practitioners of the art and as I didn't see any mention, I thought what Sir Harry learned was worth passing on. From memory, the reason he went to exhausting over the top of the sleeve was because of sleeve failures (popping out a port shaped 'panel') and of course the compactness gained on ditching the junk head was a very welcome bonus.
There is a paper that reports on later investigation into sleeve vs poppet valves and reviews the protagonists' claims. If anyone is interested, I'll try and find it and provide a link.
The asymmetry achievable with sleeves can't be ignored, but for what I'm interested in, a complication too far.
While I remember, also mentioned in the thread was the possibility of deleting piston rings. Some research was done on this by The South West Research Institute. Their angle was free piston engines as gassifiers where high ring wear could be anticipated. Their incomplete conclusions lay out a path obvious to the more imaginative among us... As above, if anyone is interested...

Is this what you meant, Pinger?

Rings do serve a useful function in primary piston heat transfer, & likely did the same for moving sleeves..

Here is Roy Fedden's list of sleeve valve merits from his Bristol work, of nearly 80 years ago..

https://www.flightglobal.com/pdfarchive ... 02830.html

& here is a more recent technical/historical/academic appraisal of the sleeve valve by an American,
who IMO, really ought to have had someone with a stronger grasp of piston engine architecture & function,
- review his thesis..

www.enginehistory.org/members/articles/Sleeve.pdf

[Pinger]

J.A.W.: Yes, the Raymond paper was the one I had in mind. Agreed, accepted wisdom says rings are the heat path from the crown. Here >> http://www.dtic.mil/dtic/tr/fulltext/u2/a193213.pdf is the SWRI paper on ringless. Shame they didn't try steel pistons in an alloy bore.
Short ring life though is really the preserve of engines configured for max power as first priority. Lower states of tune can do much to extend ring life using less aggressive porting. Go the 'bridged' route - as in X-flow outboards - and the ring can be permitted free rotation, unpegged. Free rotation reputedly extends ring life and helps prevent carbon build up.

[Pinger]

This version >> http://www.pit-lane.biz/t5235-2-stroke- ... tim-hickox lacks the referred to (in text) graphs. Does anyone have a version (or link to) that includes the graphs?