2 stroke thread (with occasional F1 relevance!)

[manolis]

Hello all.

Here is one more unconventional 2-stroke engine:



It is a PatRon Harmonically Reciprocating-Piston Rotary-Engine.



It comprises a crankshaft, a piston rotatably supported on a crankpin of the crankshaft, and a rotating cylinder wherein the piston reciprocates sealing one side of a combustion chamber.

For a complete reciprocation of the piston inside the cylinder they are required two rotations of the crankshaft.

Without external balance shafts, the balancing of the inertia force, moment and torque is perfect (even for the single cylinder).



A synchronizing gearing keeps the cylinder rotating at the same direction with the crankshaft and at half angular speed than the crankshaft; the high pressure gas in the combustion chamber does not load the synchronizing gearing.

Not only the power passes directly to the load and the synchronizing gearing remains unloaded but, additionally, the cylinder liner remains rid of thrust loads. Think how.


The stroke S of the piston along the cylinder equals to four times the distance between the (fixed) rotation axis of the crankshaft and the (fixed) rotation axis of the cylinder.

The relation between the displacement D of the piston along its cylinder and the rotation angle f of the crankshaft is like:

D=(S/2)*sin(f/2)

which is a pure sinusoidal (or harmonic) motion.




With the PatRon:

* the power passes directly to the load (more directly than in the conventional reciprocating piston engines: there is no connecting rod (the piston is rotatably mounted directly on the crankpin), there are no thrust loads on the cylinder liner),

* the synchronizing gearing remains unloaded by the high gas pressures during the compression - combustion – expansion,

* the two halves of the "immovable" casing (one per side of the spinning cylinder) are easily coupled / bridged forming a space wherein the cylinder spins safely,



* only one crankshaft is required (and only a set of balance webs secured on the crankshaft for the complete balancing of the engine),

* there are no high speed bearings loaded by heavy inertia loads,

* in case of air-cooling the rotation of the cylinder simplifies things (the cylinder is also the fan),

* if desired, the power can be delivered by the rotating cylinder (which spins at half crankshaft speed),

* it is for single acting, for double acting pistons, even for “multi-acting” single-piece pistons,

* it is for two-stroke and four-stroke engines, etc


For more: http://www.pattakon.com/pattakonPatRon.htm


In a few words:

The PatRon brings the good sealing and the small surface to volume ratio of the reciprocating piston engines in the rotary engines, without introducing significant side effects.


Thoughts?

Objections?





Hello Tommy Cookers

The meaning of the “fixed operational conditions” is that the engine operates for several seconds (or even minutes) at specific revs and load (for instance, it may take several second until the scavenging to settle down).

Thanks
Manolis Pattakos

[J.A.W.]

A up-dated old-school 'rotary' engine Manolis.. well done..

Here is a NASA paper - adding H2O injection to a 2T with DFI & above ambient pressure scavenging.

https://ntrs.nasa.gov/archive/nasa/casi ... 151108.pdf

[Tommy Cookers]

Manolis

the rotary engine was at its zenith 100 years ago ie its advantages and disadvantages were well appreciated .....
Siemens/Shukert (aka Siemens/Halske ?) tried to design out the disadvantages ......
using 2 rows of 11 cylinders in contra-rotation at half notional engine rpm driving the load (propellor) at this half notional rpm
they had reduced drag from cylinder rotation, near-zero vibration, and a more efficient propellor
and, crucially, cancellation of the so-called gyroscopic torque effects otherwise produced by angular displacement of the rotating cylinder mass etc
these effects (additive to similar effects inherent in propellors other than contra-rotating propellors) had then killed thousands of people


ie for aviation you really need the cylinder rotation to be opposite to the prop rotation
and rotation at half notional rpm is desirable for both prop and cylinders
and you need to lose the casing

even with a conventional engine the 'gyroscopic torque' from the prop can kill ..... ie
a traditional (tailwheel type) airframe design is more efficient than modern designs, but inevitably is mechanically unstable (ie in takeoff or landing)
so any directional misalignment of the aircraft orientation relative to its direction of travel will tend to increase uncontainably ie a 'ground-loop'
the prop 'gyroscopic torque' generates directional misalignment (additive to misalignment from other systematic and incidental sources)
would a traditional-type rotary engine even be certifiable for aviation use ?

but if cylinder rotation is opposite to prop rotation and suitably small the net effect can be a reduction in overall 'gyro torque' ie beneficial
aerobatic and normal manoeuvres will of course in various ways produce inconveniently alternating stresses in rotational mechanisms


btw
the rotary engine seemingly started as Gnome's response to some imaginary problems - additional to those imagined by the Wright brothers
ie a remote-siteable engine that needed no prop blast for cooling and no direct-coupled prop for flywheel effect
the over-ingenious cylinder-ported, crankcase-induction, unthrottleable single-valved Gnome evolved from the conventially (atmospheric) inlet valved
their huge official production (and huge pirate production of obsolescence for and by the enemy)
bizarre or what ?

though 100 years ago Mr Fokker's planes had all-welded 'spaceframe' fuselage structures via Reinhold Platz, his welding shop foreman

[manolis]

Hello Tommy Cookers.

I had to explain, in another forum, the differences of the PatRon rotary from the Gnome and Rhone rotary engine.


Here are some of them:


In the PatRon the center of the crankpin moves along the cylinder axis, eliminating the thrust forces between the piston skirt and the cylinder liner.

In the Rhone rotary engine (and in the conventional reciprocating engines) the center of the crankpin leaves, at the middle stroke, the cylinder axis for a distance equal to the crankpin throw, resulting in heavy thrust loads which generate friction and require (in order to avoid metal to metal contact) a thick oil film between the piston skirt and the cylinder liner whereon the piston skirt slides.

So, the one arrangement saves mechanical power, keeps the cylinder liner cooler, it requires less lubricant, the piston needs not a piston skirt (lighter piston), the connecting rod is eliminated, etc.




Regarding the connecting rod and its elimination:

In the Honda Civic VTEC 1600cc, used as the host for the pattakon VVA-roller, more at http://www.pattakon.com/pattakonRoller.htm , the piston weighs 300gr, the wrist pin weighs 100gr and the connecting rod weighs 600gr.
Take a pair of pistons with their connecting rods and wrist pins. It weighs 2Kg. It comprises two big end bearings, two small end bearings and four piston skirts (where most of the friction loss happens).
In comparison, a double acting PatRon piston (which serves two combustion chambers) weighs less than 0.5Kg and comprises just one rotating bearing and no “thrust bearings”.

As the connecting rod of the Rhone rotates around the eccentric pin holding the piston at its small end, the inertia force loading its big-end bearing is huge at high revs (think of the eccentricity of the center of gravity of the set: piston – wrist pin – connecting rod).

As the double acting piston rotates about the crankpin of the PatRon, its center of gravity remains permanently on the center of the crankpin and the centrifugal force is smaller. With the center of gravity of the double acting piston permanently on the center of the crankpin, a set of two balance webs secured on the crankshaft counterbalances completely the inertia force of the piston and the “vibration free quality” of the engine is perfect.

In comparison, the connecting rods between the piston and the crankpin of the Rhone (and of the rest conventional reciprocating piston engines) spoils the motion of the piston / wrist pin / upper side of connecting rod. Instead of being pure sinusoidal, it comprises a significant second order which makes the dwell of the piston at the TDC short and the dwell of the piston at the BDC long. It also makes bad the balancing of the engine. For instance, a 9-cylinder Rhone is by far worse in free inertia forces than a single cylinder PatRon (the same is true for the other non-rotary Radial engines, read at http://www.pattakon.com/pattakonPatAT.htm for more).



Regarding the gyroscopic rigidity:

Please look at this drawing:



and think again about “the increase in rotating mass”, about the aerodynamic losses and about the “gyroscopic effect problems”.

What I see is a thin lightweight (because, among others, it is rid of bending loads) aluminum cylinder comprising the central part of the propeller.


In case you want to get rid of gyroscopic rigidity, just drive (by means of a reduction gearing) the propeller to rotate at opposite direction than the crankshaft – cylinder. With the proper selection of the reduction ratio and of the momentum of inertia of the parts (cylinder, crankshaft, propeller) you can achieve zero gyroscopic rigidity


On the other hand, and because the PatRon is perfectly balanced even with one only combustion chamber (single cylinder), you can keep the propeller on the cylinder and put another counter-rotating single cylinder PatRon to drive another propeller (total gyroscopic rigidity: zero).

Thanks
Manolis Pattakos1

[manolis]

Hello all.


Here is a more “unconventional” PatRon for small airplanes, ultralights etc.:






It is an over-square direct injection Diesel with plenty of piston skirts.


With 120mm bore and 60mm stroke (about as over-square as the Ducati Panigale 1299) it gives a 2-Stroke capacity of 1,350cc.

The maximum dimension of the spinning cylinder is 1ft, i.e. the distance from the top of the one cylinder head to the top of the other cylinder head is only 305mm.


The scavenging is quite strange:

At some angle of the cylinder the piston opens the “leading” port and the pressure of the gas in the cylinder drops sharply.
Several (like 10 or 15) degrees later the piston opens the trailing port, too. The exhaust happens through both ports. Gradually the leading port becomes the intake port with the trailing port being the exhaust port:
The motion of the cylinder in the ambient air pushes air to enter from the leading port to scavenge the cylinder and then to exit from the trailing port.
After the BDC the pistons moves “upwards”; initially it closes the trailing port; the air entering the cylinder from the leading port continues to enter (due to inertia) until the piston closes the leading port, too.
The gas in the cylinder is compressed. Near the TDC diesel fuel is injected into the bowl at the center of the crown of the piston.
After the TDC it follows the expansion.
After the middle stroke the piston opens the leading port (it serves as exhaust port and as intake port) and so on.

I.e. it uses neither crankcase scavenging, nor some external scavenge pump.

If it works, it makes an extremely compact, simple and lightweight Diesel, which is also perfectly balanced, which also provides some 15% longer piston dwell at the TDC as compared to the conventional Diesels (the PatRon running at 5,000 rpm gives to the combustion as much time as a conventional Diesel running at 4,500rpm), and which eliminates the load between the piston skirts and the cylinder liner (the skirts are there only to seal the crankcase).

At 5,000rpm of the cylinder (i.e. at 10,000rpm of the crankshaft) it could make some 200bhp (i.e. as much as the Ducati Panigale 1299) because it is a 2-stroke.

As for its weight, 1/4 of the Panigale 1299 engine is reasonable.

As for its Brake Thermal Efficiency, it has all the characteristics for a top BTE.


This animation is explanatory:



(the same animation at slow motion is at http://www.pattakon.com/PatRon/PatRon_Model_2_Slow.gif )


Regarding the unconventional scavenging, it resembles to the way the Gnome and Rhone rotary engines (those with the ports on the cylinder liner) were running:





(more details at http://thevintageaviator.co.nz/projects ... e/historyv )

They were using the "exhaust" valve of a cylinder unconventionally: initially it was acting as an exhaust valve (during the last half of the expansion cycle and during the exhaust cycle), later (during the intake / admission cycle) it was acting as an intake valve allowing fresh "unfiltered" air to fill the cylinder; at the end of the inlet cycle rich air/fuel mixture was entering into the cylinder through the ports on the cylinder liner.



This version shows how compact the PatRon can be.

For a 1350cc 2-stroke double-acting-piston PatRon the external diameter of the rotating cylinder/cylinder head is only 1ft (305mm)

Applying the similarity (1350/50=27 and the cubic root of 27 is 3), for a 50cc version the external diameter drops to 100mm. Think of a 50cc 2-stroke 2-“cylinder”engine for a chainsaw or for a model airplane having such a size.

Thanks
Manolis Pattakos

[J.A.W.]

More amazing/mind-bending mechanical marvels!
Many thanks for sharing your imaginative concepts here Manolis...

Just goes to show, the geometric/harmonic flow aspects of the basic 2T piston engine..
.. still have as yet - unrealized - development potential.

[Muniix]

........this thread has strayed off the 2T topic basis lately ..

.........all the superbikes are gobbling air and fuel at a rate and levels that produce well over 1,000 hp of heat energy .......No wonder electric vehicle racing is taking off. We need to come up with ways to put liquid/gaseous fuels into contention again. .... When electric vehicles have a near perfect torsional torque and don't have to be designed for economy or performance they can be both at the same time. They are througing down a challenge for ICE to respond to.
With the new Tesla racing class vehicle achieving 0-100 kph in 2.1 seconds, now that is insane, not even F1 can do that and in a body that can seat 5 adults and two children and still have two boots, that is damn impressive.
........My ideas were along the lines of finding a more efficient crank train, with all the recent research interest in offset cranks and gudgens pins. If we can find ways of putting more energy into a single engine cycle and make it as efficient as possible .....
This is what interests me at the moment, clearly research shows that larger cylinders have better volume surface ratio's that assist thermodynamic efficiency.
......Maybe by using a torque filling and damping using mild hybridisation ....... Any Ideas ?

a direct drive EV has deficiencies as a direct drive ICV would have
a fast car type ICV is generally (ie at partial power) inefficient
(having a grossly over-powerful engine, slightly compensated by integral over-gearing/downsizing)

a fast motorcycle type ICV is worse, having by convention no over-gearing and no engine downsizing by turbo and/or hybridisation
natural aspiration, with gas fuelling allowing high heat dilution would be magic in this case .....ie......
at full power/torque demand near-stoichiometric fuelling is used, with leaning progressing to maybe 3 lambda at lower torques
so there's a 'full fat' unimpaired spread of power but with far better economy
far better economy because there's little or no throttling during the 99% of the time partial torque is being used
furthering efficiency by rapidly managing the cooling rate according to leaning
this lean running would be particularly beneficial to the 2 stroke

some rpm-differential boost could be included eg by using part-time electric supercharger drive and near-F1 type multiple DI
differential boost was used in (diesel) truck and locomotive engines greatly to widen the power band to 'constant power' eg Paxman 'Hy-Dyne'

the boosted heat-dilution engine is downsized re. heat loss, but not downsized re. friction eg because of high cylinder pressures with compression
better conrod geometry could help with this, and novel geometry giving SHM would eliminate 2nd order vibration or 2nd order counterbalance shafts
usefully to a motorcycle with solid-mounted/structural engine
as 2nd order vibration w/o counterbalance shafts or elastomer mountings seems to cause offence via resonance in footrests and bars

The current research papers on mild hybrid are discussing the issues in minimising the torsional vibration inherrent in internal combustion engines during transient engine operation with clever control of the hybrid electric motor providing torque filling, you only need a small amount of power storage = light weight battery pack, inverter and electric motor.

You then get the advantages of liquid fueled IC engines (if designed well) and the smoothness of electric when it effects the powertrain dynamics and more of the instant acceleration typical of electric vehicles.

With the increasing use of congestion charges and tolling based on vehicle class and emissions now becoming prevelant especially in central business districts only zero emissions vehicles will be cost effective to enter the CBD so a bike with an electric only mode for 6-12 minutes is all that is needed and a few kw of power will do with electric torque.

Soon bikes will be the only human controlled vehicles on the road and this will attract even more new riders, with the number of driverless vehicles being released not just by Tesla but everyone, companies developing 3D sensing for autonomous driving and situational awareness are all getting huge government grants. This will increase the cost of cars due to the mechanisation required, and surveys say majority of users are willing to pay the huge increase for the benefits, the others will soon join in when they realise what they are missing.

Then their is V2x Vehicle to everything to improve safety, there are huge numbers of trials and implementations now in progress, Cadilac are to have it as standard this year, with the US mandating V2x in all vehicles by my 2019 so the journals are saying this month.

I wonder what the motorcycle vendors are actually designing now to meet this rapidly approaching reality, or will a Tesla like startup beat them, nearly all the growth in motorcycle sales are coming from new young riders from the mobile era and older riders returning wanting something better than what they had 20 years ago and finding the bikes are nearly exactly the same except some software that limits the power of the new more powerfull engines, wow is that progress or what.

who is designing power plants for this environment, highly efficient, low emissions, mild hybrid with some pure electric only operation and clever electronics to integrate with V2x and situation awareness so when you are riding into the sun and can't see sh...t your heads up display in your helmet fills in what your eyes can't see and warns of possible collisions and traffic lights being red etc.

The IC engine needs to be able to pump air well through it so it has good power, good exhaust flow is essential, it is amazing how many engine designs fail in the simple issues, efficient and modern combustion systems, hmm how much pressure is at the exhaust port, where is the heat going, ...

[Muniix]

Hello Muniix.
You also write:
“Bishop . . .know how to write patents, . . . , that was what gave them their $15 million a year research and developent budget.”

Do you know how it is to apply for a patent, or how the inventor feels when a patent is finally granted?

Isn’t it a pity that after all this millions there is not one running prototype on the roads?

Anyone can apply for a patent, success is when one returns the inventor rewards by way of licensing fees, this is where bishop are used as an example to train patent lawers in how to file patents and achieve protection of the idea.

I have tried to get a major motorcycle engine designer/builder interested in you variable desmo valve gear the only response was some comment on dynamic loading and manufactuing issues, and that one patent is likely the most promising, how much revenue, or return on your investment have you received from your patents, do you know what it feels like, to have in your hands the first multi-million dollar license cheque, that is the real question.

Bishop had a very effective plan to make it a success like every other development they produced, despite this they were blocked by politics not once but twice, they filed an EU antitrust complaint and started an investigation that found there were other avenues to prove the technology, like the EU Commission was going to find in favour of an Australian company against the EU F1 companies, after the huge investment in time 18 years paying 6 or more staff and resourcing them and after the business owner died shortly after Honda decided against using a BRV single and use their own cbr600 engine in Moto2, the remaining Bishop family who inhereted the business could not see a clear path for a effective return on investment, when would a multimillion dollar licensing deal be realised, the answer was never unless they could prove it elsewhere, those avenues were thin and expensive, so instead of throwing good money after bad, and depriving other projects of funding and with the team all burned out and emotionally shattered, it was all over. The project had to be shelved there was nothing they could do that was wasn't folly or stupid business practice, the people had left to other projects for their sanity. Most people could see that and come to that exact same decision if they were paying the bills, the payroll, the office space, the power bills, the insurance, the receptionist, the software licenses ..... What is going to pay all these bills a real business has to pay every month on the first day of the month if you want good service from your suppliers.

The tooling that produces the slots in production heads costs $30,000 dollars to make.

You also write:
“Marine engines use mhp, marine hp”

Marine hp?
Please be more specific.

Thanks
Manolis Pattakos

It is the maximum power the engine can deliver at 100% duty cycle, doesn't every engineer know this stuff.

[manolis]

Hello J.A.W. and thanks..

Yesterday, in another forum a guy (CheapRacer) published this drawing :



and wrote:

“at BDC the exhaust helps drive it 'round while the open intake mouth gets self-supercharged!”



The combustion chamber is like a long room (say, a corridor) having a big window towards the north and another big window towards the south.

Outside the room there is a strong wind coming from the north (this is what the rotation of the cylinder causes).

At the end of the expansion the north window opens.
The high pressure in the room pushes a big part of the “gas” to exit from the north window and the pressure to drop sharply.

A little later the south window opens allowing gas to exit from that window too.

Due to the north wind, the flow from the north window gradually weakens, stops and reverses its direction, while the flow from the south window strengthens.

With both windows wide open (BDC), the strong north wind enters from the north window, scavenges the room (and cools down the walls, the ceiling and the floor of the room from within) and exits from the south window.

Later the south window closes, with the north window still open.

The north wind continues to enter into the room from the north window (due to inertia / ram effect) overfilling the room with air (a kind of asymmetrical port timing: the exhaust closes before the transfer).

Finally the north window of the room closes trapping the air entered, and the compression starts.

Thanks
Manolis Pattakos

[Muniix]

Hello J.A.W. and thanks..

Yesterday, in another forum a guy (CheapRacer) published this drawing :

http://www.homebuiltairplanes.com/forum ... 1488902635

and wrote:

“at BDC the exhaust helps drive it 'round while the open intake mouth gets self-supercharged!”



The combustion chamber is like a long room (say, a corridor) having a big window towards the north and another big window towards the south.

Outside the room there is a strong wind coming from the north (this is what the rotation of the cylinder causes).

At the end of the expansion the north window opens.
The high pressure in the room pushes a big part of the “gas” to exit from the north window and the pressure to drop sharply.

A little later the south window opens allowing gas to exit from that window too.

Due to the north wind, the flow from the north window gradually weakens, stops and reverses its direction, while the flow from the south window strengthens.

With both windows wide open (BDC), the strong north wind enters from the north window, scavenges the room (and cools down the walls, the ceiling and the floor of the room from within) and exits from the south window.

Later the south window closes, with the north window still open.

The north wind continues to enter into the room from the north window (due to inertia / ram effect) overfilling the room with air (a kind of asymmetrical port timing: the exhaust closes before the transfer).

Finally the north window of the room closes trapping the air entered, and the compression starts.

Thanks
Manolis Pattakos

In an ideal situation this might almost be true. Just like motorcycles in the real world they have to deal with cross-winds as they move forward at high velocity, so the fluid flows they experience are more complex, the pressures they experience, turbulence, the centre of pressure etc are all very relevant and change the situation completely, even reverse it, it depends on the pressure gradients.

Simplifing fluid flows down to rooms and windows is just too much of a stretch from reality to be considered realistic. That strong wind is going to be a lot more complex in reality, effectively travelling in and at different angles and with turbulence.

Marc

[J.A.W.]

Simplifing fluid flows down to rooms and windows is just too much of a stretch from reality to be considered realistic. That strong wind is going to be a lot more complex in reality, effectively travelling in and at different angles and with turbulence.

Marc

Muniix, if you think breezes through the fenestrations of buildings seems a tad tenuous, as analogies to reciprocating ICE's - have you seen the thread entered by 'Feliks' ?
( located 'bout 2/3rds down the title page of this E, T & C section).

Starting such an machine might be a bit problematic, unless when running, some rotational energy is
used to wind up a spring, clock-wise, or the like...

[manolis]

Hello

For the PatRon of the animation (60mm stroke, 120mm bore, 300mm external “diameter”) the eccentricity of the ports from the center of rotation of the cylinder is about 115mm (0.115m).

At 5,000rpm of the cylinder (10,000rpm of the crankshaft) the speed of the leading port is:

0.115m * 2 * pi * 5,000 rpm / 60sec/min = 60m/sec = 215Km/h = 135mph

If this engine, mounted transversely, is powering a motorcycle, then at 185Km/h the leading port sees the air coming with 400Km/h. This could give a 10%, more or less, overcharging (RAM air).


Regarding the Bishop rotary valve, the Bishop patents, the Bishop “legacy” etc, there are many recent posts of mine in this thread. Nothing changed.

Thanks
Manolis Pattakos

[J.A.W.]

Regarding potential 2T developments Manolis, what do you think of the value of adapting steam-turbine style crankcase radial gas inlet ducting ( per the captioned "nozzle chambers", or similar)?

Perhaps this would promote the possibility of a continuous flow harmonic/resonant pulse system, utilizing the eccentric crankshaft you have shown - in a multi-cylinder, say 120'/3 able to run synergistically as a unit, with its flywheels doing duty as rotary transfer valves?

[manolis]

Hello J.A.W.

I try to figure out how you mean it. A drawing would help.


By the way, a single-piece cross-piston rotatably mounted on a single crankpin



can serve two independent cylinders arranged at a cross.

The crankshaft spins about the X1 axis, the one cylinder spins about the X2 axis, the other cylinder spins about the X3 axis.

The engine is even firing.

Thanks
Manolis Pattakos

[J.A.W.]

Thanks Manolis, this drawing may explain some, except the use of the flywheels as integral 3D rotary valves.




& here: a recently designed 'swirl-entry' 2T DFI combustion chamber...

http://www.Sonexresearch.com/tecnologies/3743046