2 stroke thread (with occasional F1 relevance!)

[manolis]

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.

Thanks
Manolis Pattakos

[Pinger]

Congratulations Manolis.

[Pinger]

Thanks P, are we sure that a 'sonic thrust' - was an intent?
Or did it really serve as a 'spark arrestor" viz:

Who knows? I was just struck by how all the 2T tractors of the era arrived at a similar shape for their exhausts. 4T pipes were never so shapely but possibly they were less of a fire hazard re sparks. If ever I get the chance to peer into one of those tractor pipes - I'll take it.

& do you know what the function of the pipe - plumbed into it - is?

Nope. Only that not all tractors of the type feature it. Possibly something to do with cold starting - being 'hot-bulb' engines, there was something of a ritual to be enacted prior to firing up. They were crankcase scavenged though - but no mention of lubrication (fuel was injected directly into the 'bulb')

[Pinger]

the Garelli seems to have used a straight pipe before 1925
ie is the photo from Brooklands ? - are there later photos of Garellis ?

Valid question re a Brooklands bike.

in a 1920s motorboating magazine the writer describes giving his motor a tuned length (plain) pipe by experiment with a slip joint
iirc gaining 6 knots from the inboard 2 stroke

That's pretty much the way that divergent cones adopted by those racing outboards came to be as well I think. In their case, ''sucking out the heat'' was paramount. The development of expansions with a convergent cone appears to be a little accidental also - making efforts to quieten the megaphone, some found the engine ran better. I guess the science of calculation came later. Possible I suppose that many were working completely oblivious as to what others were doing and had done before. I don't suppose if you'd just 'invented' the expansion chamber that was giving your bikes such an advantage you'd be telling everyone you got the idea from a tractor...

[Muniix]

Hello all.

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

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

a patent is granted for the PatRoVa Rotary Valve.

The patent number is US9,677,434.

Thanks
Manolis Pattakos

Business hat on;. Why else would one spend money on something if it wasn't giving pleasure etc. To make s return on the investment.

What is the PE ratio on your patents? 1:50 ?

Bishop typically get a return of $30-40 million a year on their patent portfolio, each patent initially costing ~ $20,000 filed so it gives the necessary protection.

How much are you spending on protection of your Innovations, total cost per year?

How much $$$$ have they returned?

It is a valid question, just a ratio will do.

It's not like they are hot porn, to get your rocks of with, or a substitute for short man syndrome.

[Muniix]

I still haven't got any answer or proof of your claim that your Patrova head can achieve the VE you keep claiming. I have asked many times, only response if any is a deflection.

Then i am the I've that gets my posts deleted and abused, when clearly I'm not the one making unjustified claims.

I've been told these posts are hilarious at certain F1 teams. Marc stop wasting your time on this ....., But they are so funny, you take him down so well, causing him to over react in some instances, "how big big enough that you could put a while Bishop valve through it"

If someone knew there was a problem with one of my ideas and didn't tell me I'd be upset the didn't. I would want them to tell me. Let me think it through.

Your inlet channels​ are effectively​ a T once they have gone past fully open and before closed. The intake running across the top of the T with the bottom leading into the cylinder, the faster your engine speed the higher the intake inertia is, increasing pumping losses and load on the crankshaft. Lower the cylinder pressure. This clearly shows your claims are false.

when the valve is past fully open the inertial energy in the flow means it wants to go straight past the window and not into the cylinder but keep flowing within the valve as it rotates. It doesn't have the geometry advantages of the Bishop valve here that turns the trailing edge flow a perfect 90 degrees.

Can we please get some clarification as to why you think it will be better than the Bishop?

[manolis]

I still haven't got any answer or proof of your claim that your Patrova head can achieve the VE you keep claiming. I have asked many times, only response if any is a deflection.

Then i am the I've that gets my posts deleted and abused, when clearly I'm not the one making unjustified claims.

I've been told these posts are hilarious at certain F1 teams. Marc stop wasting your time on this ....., But they are so funny, you take him down so well, causing him to over react in some instances, "how big big enough that you could put a while Bishop valve through it"

From page 97, post #1443:


On 13 January 2017 at 17:18, <man@pattakon.com> wrote:

Hello Marc.

. . .

Are you confident about your calculations?

A bet, starting with US1,000$ that increase geometrically depending on the mistake / error of your calculations (I explain in the following how) can make things interesting.

According your e-mails, there is a running (and in perfect condition) Honda CRF450 with the Bishop rotary valve on it.
I suppose there is a dyno test which can be reconfirmed any time it will be asked by me (we can arrange how).
I suppose, also, the dyno test is not confidential.

So, here is how the "bet" will "work":

You will start with the dyno test of the specific Bishop CRF450, you will calculate (it will be easy based on the 200% better flow of the Bishop) the fall of the peak power in case the cylinder head is replaced by a PatRoVa, and you will provide me the data.

Then I will modify a Honda CRF450 to PatRoVa (the form of the window(s) / ports, the diameter of the valve and every other detail of the design is my own business).
And I will dyno test it (with the dyno test being reconfirmable if you ask so (we can arrange the details)).

If you are correct, you will take my US1,000$ and the satisfaction you know what you say.

If not, for every +10% difference in peak power (the 10% refers to the peak power of "your" Bishop CRF450) from your calculations, the amount to be paid by you doubles.
For instance, if the Bishop CRF450 makes on the dyno 100PS, and according your calculations no more than 60PS peak power can be made by the PatRoVa CRF450, then, if the dyno writes 110PS for the PatRoVa CRF450 (i.e. 5*10% above your calculation), you will pay to the UNICEF (not to me) 2^5=32 times the initial amount of the bet (i.e. US32,000$) and you will sent me the receipt to publish it in the PatRoVa web page.

The US1,000$ I will pay in case you prove correct, may seem not much, however don't forget the cost to make a decent quality PatRoVa prototype,

If your friends at Bishop like so, they can bet, too.

Have a nice day.
Manolis Pattakos

[manolis]

Hello all.


The 850 E-TEC of Rotax is regarded as the most advanced 2-stroke.

A special direct injection (in combination with an auxiliary indirect injection for the high revs), as well as a special lubrication system for the crankshaft bearings, make it one of the greenest 2-strokes ever, without compromising on the performance (165bhp at 8,000rpm from 850cc, i.e.170mN/lit specific torque at peak power).


A 200:1 (or higher) fuel to oil ratio seems reasonable / attainable (in previous posts they were mentioned some good 2-strokes operating at 300:1 and 400:1 fuel to oil ratios).



However, in the “official” youtube video for the 850 E-TEC, Rotax gives the fuel consumption as “up to 12.5lit/100Km” and the oil consumption as 1lit/300Km.

A rough calculation “talks” for less than 50:1 fuel to oil ratio, which is quite strange for a “green” engine.


In practice, things are even worse:

At http://www.snowandmud.com/ski-doo-rev-g ... ption.html there is a forum discussion about the “850 crazy oil consumption!” wherein they talk for 30:1 fuel to oil ratio.


With such an oil consumption, the Rotax 850 E-TEC has a strong disadvantage for use in cars and/or motorcycles (pollution, running cost etc).

Do I mish something?

Thanks
Manolis Pattakos

[J.A.W.]

Hi Manolis,

What needs to be taken into account with snow & watercraft compared to wheeled vehicles in on-road use,
is the significant difference in typical/everyday periods.. at max power output..

Most cars & motorcycles operated in public settings on-road, function on a fraction of the available power settings,
with modest drag - certainly compared to those required - to move fast, going WOT uphill - through heavy snow..

A high-performance car or motorcycle - which approaches the specific output of the Ski-Doo - running hard
on the autobahn at high power/drag ratios would also use significantly more fuel than its 'official' figures..

Another factor is drive slippage - since - unless the wheels are spinning with traction-loss, on-road odometer readings are fairly accurate, whereas the 'loose' drives in snow & watercraft means there is often a significant difference
ratio-wise, between engine rpm & forward movement recorded as distance, & especially so - in hard running.

This video shows how hard snowmobiles are run: https://www.youtube.com/watch?v=GVSyUuqLKIw

4T engines which are operated under similar circumstances certainly have "Oil level check - before use" warnings..

(Well done on the patent grants, too)

[manolis]

Hello J.A.W.

From the fuel consumption data provided by the Evinrude for their E-TEC G2 marine engines (post #1197), their 2-strokes appear better than some reputable 4-strokes.

However the problem it is not the fuel consumption of the Rotax E-TEC.

The problem is the extreme specific lube consumption.

Despite their “innovative” crankshaft-bearings-lubrication-system, they cannot help burning lots of lubricant (as a percentage of the fuel burnt, I mean, no matter how they measure the kilometers covered by the sled).

Besides the increased pollution caused by the lubricant, the lubricant also increases the running cost (they use synthetic lubricant of a specific type, i.e. an expensive oil).

With 50:1 fuel to oil ratio and, say, 5 times higher cost per liter for the lubricant relative to the fuel, a 10% higher “fuel” cost results.


Rotax / BRP / Evinrude should look for better solutions like:



Thanks
Manolis Pattakos

[FW17]

Why not someone put a G2 in a Caterham 7 and just check what happens with oil system.

[J.A.W.]

A torquey 3.5 Ltr 300 hp G2 engine in a Caterham 7 would not be working very hard ( though the chassis would be)..

That 30-to-1 oil ratio for the significantly higher specific output 850 Ski-Doo would be a WOT safety rating,
& is by no means unusual for hard running performance 2Ts - which also - make best power on such oil settings..

[uniflow]

I see KTM have copied my Transfer Port Injection (TPI), same as the system I have shown here some time ago running on my YZ250 . Approx five years ago I had this system up and running with testing showing between 14 and 21% fuel savings over a standard YZ, same day, same track , same riders alternating bikes same top end power.This fuel burn has been tested again and again in the REAL world. It would seem KTM have seen my youtube and general postings on various forums, good on them, I'm glad someone has taken up the design and is using it, Im waiting on my free bike as payment . Same injector positioning aiming toward the incoming air in the B ports, same same. Actually I call it DTPI delayed transfer port injection as this is the trick. The fuel charge is delayed for a time before it is introduced into the air stream making it hard for the fuel to escape the cylinder ( runs out of time ) . Also the positioning of the injectors in the B ports helps stall short circuiting, off the pipe where short circuiting is worst.
As you would expect I have a mark two injection system that is BETTER than the original but it won't be shown here.
Twostrokes need a minimum of 40 to 1 oil at full throttle but under approx 60% torque they can be leaned out to 300 to 1 at idle.
The oil problem is a real problem for twostrokes but the raw hydrocarbons out the exhaust is the first big problem to overcome, this new system solves this problem (the mark two) . I have two oil less top ends on test here in my workshop, fourstroke bottom ends, also can't be show here. How ironic, looks like the twostroke is the future engine.
https://youtu.be/hOGZ5llowoU
https://youtu.be/1YG9ko8-Nwk
And the original TPI prototype first running in 2008, still running and entering events and no one is even aware of whats inside.
https://youtu.be/CnIemdISKrM

[FW17]

Maybe some one should try using air as a lubricant for the piston cylinder interface while using a dry sump system for the other bearing areas.

[Pinger]

As you would expect I have a mark two injection system that is BETTER than the original but it won't be shown here.
Twostrokes need a minimum of 40 to 1 oil at full throttle but under approx 60% torque they can be leaned out to 300 to 1 at idle.

Pretty sure some (oil injected) 2T outboards allow for emergency return to port at very low throttle with an empty oil reservoir. Confirming how little oil they need at low load.
I read a theory that says 2T lubrication is via a reservoir of oil accumulated in the crankcase and flung by the crankwheels. Which would explain the plumes of smoke when then going from small to large throttle openings but what then provide lubrication for continued arduous operation if the oil has gone? Bogus or real theory?

The oil problem is a real problem for twostrokes but the raw hydrocarbons out the exhaust is the first big problem to overcome, this new system solves this problem (the mark two) . I have two oil less top ends on test here in my workshop, fourstroke bottom ends, also can't be show here.

Is 2T oil a problem because it is additional to fuel when running at stoichiometric (or richer) and burning is incomplete due to lack of oxygen? My car when the oil control rings were shot and was using 0.5l of oil for every 25l of fuel still passed UK annual MOT tests with a 200ppm limit for UBHC and never showed blue smoke. In its case though, the suspicion is that the excess oil was compensated for by reducing fuel (under Lambda sensor control). For lower duty (say 75hp/litre specific output) 2T, could the fueling not be reduced to compensate for the oil?
Or does the oil escape combustion through the exhaust port even when fuel lost there is eliminated? Could a cat converter deal with it if fuel loss was checked? If all charge loss is eliminated – including pure air in the case of DI – can fuel injection then be controlled by Lambda sensor? Talking of... pity you are unable to show us version mark2.

How ironic, looks like the twostroke is the future engine.

In Blair’s Design and Simulation book he cites a quotation attributed to someone back in 1968 essentially saying that when emissions of NOx become problematic, the 2T will be revisited. In what format though?