2 stroke thread (with occasional F1 relevance!)

[FW17]

Manolis / Uniflo

This probably was asked of you before but I'll ask it anyway

Has either of you tried replicating the Honda Activated Radical Combustion technology as seen in EXP2 in any of your projects?

[J.A.W.]

Manolis, FYI, there is a Ryger patent ( including diagram drawing) listed on the Euro patent site, ref: WO207142512(A1)

[J.A.W.]

Manolis / Uniflo

This probably was asked of you before but I'll ask it anyway

Has either of you tried replicating the Honda Activated Radical Combustion technology as seen in EXP2 in any of your projects?

W-F1, FYI, the Evinrude E-TEC DFI outboards utilize a similar auto-ignition scheme for high-efficiency low rpm work..

I have experienced it on an old-school carbed 2T - as an adverse run-away event due to a split/air-leak rubber inlet stub..
..flicking the ignition kill-switch had no effect, nor did shutting the throttle, which was a tad disconcerting..

[manolis]

Hello WilliamsF1

We did some tests but with 4-stroke engines having VVA (Variable Valve Actuation) in their cylinder heads.
If you can control the lift and duration of the valves (especially of the exhaust valves) you can run the engine without spark plug when you like so.
We also did tests wherein the control of the load was based on the lift of the exhaust valves.

Thanks
Manolis Pattakos

[manolis]

Hello J.A.W.

Please check the publication number.

The WO207142512(A1) number seems as the publication in the WIPO - PCT of an international application which does not exist.

I checked the name Ryger in the Espacenet . There are 12 documents, none of which fit with Ryger's 2-stroke.

Thanks
Manolis Pattakos

[J.A.W.]

Hello J.A.W.

Please check the publication number.

The WO207142512(A1) number seems as the publication in the WIPO - PCT of an international application which does not exist.

I checked the name Ryger in the Espacenet . There are 12 documents, none of which fit with Ryger's 2-stroke.

Thanks
Manolis Pattakos

Hi Manolis,

Sorry you had difficulty finding the patent, it is listed in Espacenet.
The Euro Patent Application Number is WO2006NL50113220060602
Listed applicants are Sevilla Beheer (NL) ; Noordbruis Lambertus (NL) ; Gerrits Gerrit Hendrick (DE) .

G.G. Hendricks is also listed as ( Inventor).

Due to the dates listed, I wonder if matters have developed significantly since then.

[uniflow]

Manolis / Uniflo

This probably was asked of you before but I'll ask it anyway

Has either of you tried replicating the Honda Activated Radical Combustion technology as seen in EXP2 in any of your projects?

Why replicate it when we could do better? I do have a side project running, well it will be in the new year also, that uses a type of HCCI, no spark plug and the ability to change the timing (HCCI ignition point) with RPM and load. COULD be fuel controlled only with the intake being open (not throttled) but this we WILL have to test. It will be interesting.

[J.A.W.]

Why replicate it when we could do better? I do have a side project running, well it will be in the new year also, that uses a type of HCCI, no spark plug and the ability to change the timing (HCCI ignition point) with RPM and load. COULD be fuel controlled only with the intake being open (not throttled) but this we WILL have to test. It will be interesting.

That will be something, Uniflow.. AFAIR, Harry Ricardo tried to achieve this with his R-R Crecy research mill, many moons ago..

[manolis]

Hello J.A.W.

A zero was missing: the correct publication number starts with WO2007, which indicates the year of publication in the WIPO, and not with WO207.

I saw the patent application. Thanks.

It was filed ten yers ago.

How it relates with Ryger or Ryger's 2-stroke technology?



Hello Uniflow.

You write:
"I don't know what Ryger has up his sleeve, although I think I have a fair idea . . .
My Ryger development engine has a different piston sealing method that has no inertia problems, it stays put."


Quote from http://www.pattakon.com/pattakonPatMar.htm



Compression and oil control rings are mounted into grooves / ring-lands at the bottom of the cylinder; these rings slide over the external surface of the piston skirt (red), they seal the combustion chamber from the crankcase and they run "cold".
Other rings mounted into grooves / ring-lands made on the "waist" of the pants-shaped shell (cyan) slide along the inner surface of the piston skirt (red) and seal the space underside the piston crown from the crankcase.
Without rings sliding over the inner surface of the cylinder (blue), the cylinder can be made of various materials and needs not special treatment (like honing).

Thanks
Manolis Pattakos

[J.A.W.]

Hi Manolis, for an idea of the relationship between G.G. Hendricks & Ryger.. see here below, trademark.markify.com/trademarks/ctm/ryger/014093306

[Tommy Cookers]

.... Autoflight 700 twin, designed for aviation use. Water cooed, case reed, internal gear reduction. Uses a balance shaft. This is the prototype, two more engines are now available for test. New engines have the balance shaft internal, water pump in a different place, electric start. Future development to become semi direct injection with oil less top end, all proven technology, just needs to be applied.

this has been puzzling me ....
what balance shaft would a parallel twin 2 stroke have or benefit from ??

afaik eg 582 Rotax has no counterbalance shaft
(maddeningly, some seem to call the crankshaft (torsional) damper a counterbalancer - maybe there's inaccurate literature around ?)

the 582 seemed imo to have crankshaft failures due to the torsional frequency degradation with some props and reduction gear
these of course should be properly modelled at the design stage (eg look at the valuable free info from EPI Inc)
the reduction gear and associated props can be a menace to the crankshaft etc (as proper aviation found out 85 years ago)

I had drafted a post suggesting a long-stroke 'flat twin' ie designed around (and only for) direct drive ....
and notice that Manolis seems to find direct drive useful or at least useable

[manolis]

Hello Tommy Cookers

An even firing 2-stroke parallel twin (crankpins at 0 and 180 degrees) needs a first order counter-rotating balance shaft to counter the – otherwise – strong inertia moment.

First order means that its speed equals to the crankshaft speed.
Counter-rotating relative to the crankshaft.


The height the balance shaft is arranged is not important (you can put it under the crankshaft, or at the side of the crankshaft or even above the cylinder head).

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

Thanks
Manolis Pattakos

[Tommy Cookers]

An even firing 2-stroke parallel twin (crankpins at 0 and 180 degrees) needs a first order counter-rotating balance shaft to counter the – otherwise – strong inertia moment.
First order means that its speed equals to the crankshaft speed.
Counter-rotating relative to the crankshaft.
The height the balance shaft is arranged is not important (you can put it under the crankshaft, or at the side of the crankshaft or even above the cylinder head).

EDITED HERE - to correct my original wrong explanation
the moment is relatively large only around tdc and bdc and trivial eg around midstroke
rotation causes counterbalance shaft and crankshaft moments, adding to cancel the reciprocation moment around tdc and bdc
and around midstroke the counterbalance and crankshaft moments are opposite and cancel each other

but no such 2 stroke motorcycle (eg 500 cc Suzuki) ever had it
hence my question about the Rotax
my 4 stroke Suzuki etc had this (also similar 500 Yamaha and Laverda)
but it didn't seem to be brilliant, or much better than the 500 cc 2 stroke

[manolis]

Hello Tommy Cookers.

With the proper balance webs on the crankshaft and the proper first-order counter-rotating balance shaft the balancing of the inertia moment of the even firing 2-stroke parallel twin is perfect along all crankshaft angles (i.e. the unbalanced inertia moment is zero for every crankshaft angle).

I.e. the first order counter-balance shaft is the absolute cure for the unbalanced inertia moment of an even firing parallel-twin 2-stroke. If there is interest, I can further explain it.

What is left unbalanced is a second order inertia force and a second order inertia torque. They are half (because there are only two pistons) as compared to the inertia force and inertia torque of a four-in-line even firing 4-stroke.


In comparison, the Cross-Radial PatAT ( http://www.pattakon.com/pattakonPatAT.htm ) is full balanced (better than the best eight cylinder 4-strokes).

Thanks
Manolis Pattakos

[uniflow]

.... Autoflight 700 twin, designed for aviation use. Water cooed, case reed, internal gear reduction. Uses a balance shaft. This is the prototype, two more engines are now available for test. New engines have the balance shaft internal, water pump in a different place, electric start. Future development to become semi direct injection with oil less top end, all proven technology, just needs to be applied.

this has been puzzling me ....
what balance shaft would a parallel twin 2 stroke have or benefit from ??

ok, you might run one at twice engine rpm
as I to this day believe (but not yet checked this ) my 1977 Suzuki GS400 twin did
(though one antipodean 4 stroke parallel twin implies it's solveable by rod ratio)

afaik similarly eg 582 Rotax has no counterbalance shaft
(maddeningly, some seem to call the crankshaft (torsional) damper a counterbalancer - maybe there's inaccurate literature around ?)

My counter balance shaft runs at crank speed, counter rotating. The engine ran for a very short time before the exhausts started to crack around the headers (spring and rubber mounted) but after the counter shaft fitment not a single exhaust problem. I see now why Rotax run their sperical exhaust connection on a two into one header, otherwise the Rotax exhausts would crack also. Make no mistake the 582 vibrates it's just that we have learnt to live with it. The difference in my 700 twin is night and day.