Page 25 of 33 FirstFirst ... 152324252627 ... LastLast
Results 361 to 375 of 492

Thread: the clean two-stroke thread

  1. #361
    Join Date
    7th October 2015 - 07:49
    Bike
    honda ns 400
    Location
    Lithuania
    Posts
    469
    Little work on KTM SX 300 with Flettners TPI type. The owner only request to replace the piston, but we could not miss this opportunity.
    Only minor corrections, squish from original 1.7 mm to 1 mm, slightly radiused piston, corrected and reshaped combustion chamber to restore compression. We didn't tell the owner anything about it, just wanted to use him as a “live dyno”. Later he called in doubt is it really his engine. At the bottom its like a 450 four stroke with two stroke top end.
    It looks like with more changes on this engine, could be very interesting results. Very nice back flow restriction space, between crank and reed room floor.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	20200914_132710.jpg 
Views:	113 
Size:	577.0 KB 
ID:	347439   Click image for larger version. 

Name:	EXc 300 std.jpg 
Views:	114 
Size:	634.3 KB 
ID:	347434   Click image for larger version. 

Name:	Modified.jpg 
Views:	127 
Size:	506.2 KB 
ID:	347435   Click image for larger version. 

Name:	Flettner s TPI.jpg 
Views:	109 
Size:	681.3 KB 
ID:	347436   Click image for larger version. 

Name:	20200914_160326.jpg 
Views:	125 
Size:	771.4 KB 
ID:	347437   Click image for larger version. 

Name:	Ktm 300.jpg 
Views:	104 
Size:	650.3 KB 
ID:	347438  

  2. #362
    Join Date
    4th September 2017 - 10:39
    Bike
    Daelim besbi 2008
    Location
    España
    Posts
    300
    Quote Originally Posted by katinas View Post

    Ceci, downside of "plate on rod concept", apart of additional moving parts, is that this not eliminated the oil for main piston. With Ryger, just very small amount of oil is needed, as there is no forced contact between main piston and cylinder.
    thanks i did not take into account the lateral forces of the crank thrust


  3. #363
    Join Date
    10th February 2005 - 20:25
    Bike
    1944 RE 1
    Location
    Auckland, New Zealand.
    Posts
    2,243
    There are several other ways of translating liner force to rotating force - With a piston engine this is always necessary, so the piston (with the normal crank arrangement), as well as having to translate the pressure in the cylinder into (linear) force, it is also being used as a crosshead to translate that linear force into rotating force! - I think that the piston can be relieved of that extra duty (and there are several ways of doing this) then it can be lightweight and with no side forces acting on it, will require much less lubrication.
    Even the Ryger system has it's problems in this area.

    The Ryger (I believe) will still have problems trying to maintain a good seal while trying to deal with sidethrust in the narrow part of the piston.

    The rotary engine (not only the Wankel) will make these problems go away of course, but will bring some other major problems of its own!

    The "free piston" engine did look promising but obviously, for some reason it hasn't actually got it's act together as yet! - if it did come to pass, then obviously it would be most useful with a "Hybrid" type transmission.

    I don't believe that EV (like most other things) is the total answer, but they are going to be just that in the cities.
    In 'wheeled' vehicles elsewhere, hybrid style transmission will probably be used a lot and if the two stroke can survive, it will have to be adapted to this mode of transmission.
    (competition is a totally separate issue, but will generally follow the "real world" trends).

    These are only my suggestions of course and I could be wrong - but, I just feel that it's the only real hope for a road going two stroke!
    Strokers Galore!

  4. #364
    Join Date
    4th September 2017 - 10:39
    Bike
    Daelim besbi 2008
    Location
    España
    Posts
    300
    Quote Originally Posted by WilDun View Post
    You know, I really don't think we have evolved much since those days (in the IC world) - there were so many very good ideas which were dismissed as being ridiculous!

    This is one of those ridiculous ideas

    https://patents.google.com/patent/US...mp+fuel+engine


  5. #365
    Join Date
    10th February 2005 - 20:25
    Bike
    1944 RE 1
    Location
    Auckland, New Zealand.
    Posts
    2,243
    Quote Originally Posted by ceci View Post
    ........ ridiculous ideas .......
    What amazes me is that even though they invented all those great engines, ........ they still hadn't even thought of Phillips Head screws or Allen screws/bolts!
    Strokers Galore!

  6. #366
    Join Date
    24th February 2013 - 08:12
    Bike
    1993, suzuki rgv250
    Location
    Sweden
    Posts
    92
    I find it interesting that Lennarth Zander, with an ongoing history as one of the leading powertrain engineers at Volvo Cars and Scania CV, found it worthwhile to consider the two-stroke as a range extender for BEV/HEV. And yes, he does have a passion for two strokes. Attached article from a presentation for ongoing projects 2019 at Chalmers University of Technology, Sweden.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	2S-REX-1.jpg 
Views:	111 
Size:	187.3 KB 
ID:	347446   Click image for larger version. 

Name:	2S-REX-2.jpg 
Views:	90 
Size:	146.0 KB 
ID:	347445  

  7. #367
    Join Date
    4th December 2011 - 22:52
    Bike
    Yamaha XJ750 1982
    Location
    South Africa
    Posts
    219
    Lennarth Zander also wrote a nice book " Internal Combustion Engine: Gasexchange and Boosting"

  8. #368
    Join Date
    4th December 2011 - 22:52
    Bike
    Yamaha XJ750 1982
    Location
    South Africa
    Posts
    219
    Quote Originally Posted by WilDun View Post
    What amazes me is that even though they invented all those great engines, ........ they still hadn't even thought of Phillips Head screws or Allen screws/bolts!
    NASA's attempt:

    https://www.techbriefs.com/component...machinery/3135

  9. #369
    Join Date
    4th September 2017 - 10:39
    Bike
    Daelim besbi 2008
    Location
    España
    Posts
    300
    Quote Originally Posted by Vannik View Post


    Covid and other health problems have given me time, too much, so much that I get bored.
    And this has made me discover that there is nothing new or improved.
    Example: https://journals.sagepub.com/doi/10....949_161_024_02

  10. #370
    Join Date
    20th April 2011 - 08:45
    Bike
    none
    Location
    Raalte, Netherlands
    Posts
    3,340
    Quote Originally Posted by ceci View Post
    Covid and other health problems have given me time, too much, so much that I get bored. And this has made me discover that there is nothing new or improved.
    Example: https://journals.sagepub.com/doi/10....949_161_024_02
    That would have been about fifteen years before Gordon Blair revealed a similar system at Queens University Belfast....

  11. #371
    Join Date
    28th August 2015 - 00:01
    Bike
    1975 Hodaka Wombat
    Location
    Eugene, Oregon, USA
    Posts
    302
    This is a paper on a system I could consider building. I'm sure it isn't as good as Blair's method, but I'm more interested in visualization to get a general idea of what's happening. Hopefully, 3D printing would make the transfers rough enough to avoid laminar flow.

    Lohring Miller

    Click image for larger version. 

Name:	Transfer Flow Visualization.pdf 
Views:	62 
Size:	309.5 KB 
ID:	347461

  12. #372
    Join Date
    4th December 2011 - 22:52
    Bike
    Yamaha XJ750 1982
    Location
    South Africa
    Posts
    219
    Quote Originally Posted by Frits Overmars View Post
    That would have been about fifteen years before Gordon Blair revealed a similar system at Queens University Belfast....
    Blair was quite taken aback when he discovered Sammons' idea predates his was not only identical to his but predates it by quite a bit. Once he discovered it he gave credit to Sammons. Sammons first published it in 1949 and Blair developed his in the early 80's, so more like it predates his by 30+years.

  13. #373
    Join Date
    4th September 2017 - 10:39
    Bike
    Daelim besbi 2008
    Location
    España
    Posts
    300
    Quote Originally Posted by Vannik View Post
    Blair was quite taken aback when he discovered Sammons' idea predates his was not only identical to his but predates it by quite a bit. Once he discovered it he gave credit to Sammons. Sammons first published it in 1949 and Blair developed his in the early 80's, so more like it predates his by 30+years.

    Result of this research work, is this patent

    http://patentimages.storage.googleap.../US2573989.pdf
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	sammons1949.jpg 
Views:	141 
Size:	133.2 KB 
ID:	347462  

  14. #374
    Join Date
    12th March 2010 - 16:56
    Bike
    TT500 F9 Kawasaki EFI
    Location
    Hamilton New Zealand
    Posts
    2,764
    gearbox is in and bottom crankshaft.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	20201023_091100.jpg 
Views:	116 
Size:	798.2 KB 
ID:	347553  

  15. #375
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    430
    Quote Originally Posted by Flettner View Post
    gearbox is in and bottom crankshaft.


    cheers, Daryl.

Thread Information

Users Browsing this Thread

There are currently 3 users browsing this thread. (0 members and 3 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •