Page 2125 of 2139 FirstFirst ... 11251625202520752115212321242125212621272135 ... LastLast
Results 31,861 to 31,875 of 32072

Thread: ESE's works engine tuner

  1. #31861
    Join Date
    28th August 2015 - 00:01
    Bike
    1975 Hodaka Wombat
    Location
    Eugene, Oregon, USA
    Posts
    113
    Quote Originally Posted by husaberg View Post
    Lohring i posted a while ago mirco fuel injection stuff a university student was selling Pico or something.
    https://www.popularmechanics.com/car...tors-15682450/
    https://www.fastcompany.com/3004342/...-fraction-cost
    http://spark.annarborusa.org/feature...4Feature2.aspx
    Very interesting, but can you actually buy a unit? Their web site is under construction. I'll see if their email works.

    Lohring Miller

  2. #31862
    Join Date
    7th September 2009 - 09:47
    Bike
    Yo momma
    Location
    Podunk USA
    Posts
    4,390
    Quote Originally Posted by F5 Dave View Post
    It's a win Rob. I've beat Dennis on my 50 he on a fast 100. There might have been reasons but I feel they aren't important.
    Did he loan you a crank seal???
    ..................

  3. #31863
    Join Date
    7th September 2009 - 09:47
    Bike
    Yo momma
    Location
    Podunk USA
    Posts
    4,390
    Quote Originally Posted by F5 Dave View Post
    So chainsaw fuel injection may be not a relevant model to follow for the racing motorbicycle.
    and I thought my Husky 460 Rancher was the business...
    https://www.youtube.com/watch?v=so2N2PAtzgs
    ..................

  4. #31864
    Join Date
    12th March 2010 - 16:56
    Bike
    TT500 F9 Kawasaki EFI
    Location
    Hamilton New Zealand
    Posts
    1,963
    Not a lot of feathering the throttle there.

  5. #31865
    Join Date
    25th March 2004 - 17:22
    Bike
    RZ496/Street Triple R/GasGas/ etc etc
    Location
    Wellington. . ok the hutt
    Posts
    16,709
    Quote Originally Posted by jasonu View Post
    Did he loan you a crank seal???
    Pretty sure I replaced that. Or bought you a beer.

    Or drank one in your honour. It's a fuzzy reality at best.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  6. #31866
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    205
    Quote Originally Posted by TZ350 View Post
    Because when you throttle off, the pipe resonance collapses and so does the airflow. Current 2S EFI systems don't cope well with dramatic changes in pipe suction.

    Currently there is no proven method I know of that can detect this change of airflow in a high performance single cylinder racing two stroke.
    Because when you throttle off, the airflow collapses and so does the pipe resonance.

    How about an unrestricted reed valve at the inlet, control the airflow (engine speed, rates of accel & decel) with metered fuel delivery and maintain pipe pressure & temp for instant response by throttling the chamber outlet. Forget about asking it what it really wants, instead, just tell it what you want it to do! ....

    Cheers, Daryl.

  7. #31867
    Join Date
    20th April 2011 - 08:45
    Bike
    none
    Location
    Raalte, Netherlands
    Posts
    2,725
    Quote Originally Posted by Pursang View Post
    How about an unrestricted reed valve at the inlet, control the airflow (engine speed, rates of accel & decel) with metered fuel delivery and maintain pipe pressure & temp for instant response by throttling the chamber outlet. Forget about asking it what it really wants, instead, just tell it what you want it to do!
    I think you just invented the Diesel Daryl.

  8. #31868
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    205
    Quote Originally Posted by Frits Overmars View Post
    I think you just invented the Diesel Daryl.
    The unrestricted inlet and the exhaust brake are Dieselly...
    The ability to out compression brake 4-strokes is a bonus, plus a great new 'noise' to frighten the horses.

    The rest is still Otto.
    There might be a couple of cycles of (potentially) exhaust contaminated or lean mixture on transition back to accelerate mode.
    The FI could perhaps inject a little extra fuel initially, to manage this. (Just like an accell pump does)
    A retarded spark or two and the rich mixture might quickly put some heat & pressure back into the pipe, to fire it up again.
    The stinger throttle should not be direct by cable to the twist grip. It will really need its own control circuit monitoring things like:
    Throttle position, RPM, pipe temp & pressure, brake activation & pressure , decell rate (G force) etc. (A fart by wire system).

    Cheers, Daryl.

  9. #31869
    Join Date
    28th August 2015 - 00:01
    Bike
    1975 Hodaka Wombat
    Location
    Eugene, Oregon, USA
    Posts
    113
    Exhaust throttles were once common in model boat race engines. The throttle was usually located at the beginning of the header. Sticking and leakage were problems. Recently stinger throttles were also tried. They seem to be equally effective without the header throttle problems. Users claimed that the throttle response was better than with conventional carbs. These engines run alcohol based high nitro (60+%) fuels so the exhaust temperatures are low. As far as I know they haven't been tried on gasoline engines.

    Lohring Miller

    Click image for larger version. 

Name:	Stinger Exhaust Throttle - Andy Brown.JPG 
Views:	79 
Size:	424.4 KB 
ID:	341886Click image for larger version. 

Name:	Nitro motors II 008.jpg 
Views:	78 
Size:	120.5 KB 
ID:	341885Click image for larger version. 

Name:	Stinger Exhaust Throttle - Charles Perdue.jpg 
Views:	79 
Size:	193.8 KB 
ID:	341887

  10. #31870
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    205
    Thank you for your interesting input Lohring.

    I'm pleased to know that i'm not just 'brain farting' into the wind.

    Cheers, Daryl

  11. #31871
    Join Date
    16th April 2018 - 08:17
    Bike
    RC51
    Location
    USA
    Posts
    19
    TZ350 - this is probably a totally dumb idea, but what about using a pressure signal from the intake or exhaust to control fuel flow by manipulating the fuel pressure regulator? The collapse of resonance would reduce intake vacuum and reduce pipe pressure. If you could feed that pressure event to the regulator, wouldn't it help add another dimension to the fuel mapping? Of course, these would be average pressures so some sort of buffering would be needed to apply the average pressure to the regulator. Although it wouldn't be a complete solution, it might help some problem areas of the EFI tuning.

  12. #31872
    Join Date
    18th May 2007 - 20:23
    Bike
    RG50 and 76 Suzuki GP125 Buckets
    Location
    Auckland
    Posts
    9,764
    Quote Originally Posted by flyincat View Post
    TZ350 - what about using a pressure signal from the intake or exhaust to control fuel flow by manipulating the fuel pressure regulator?
    That is not a bad idea.

    It turns out that the collapse of pipe resonance allows the intake, crankcase and average pipe pressure to all increase to near atmospheric (0.95 bar or so). When the pipe is resonating well everything is at a lower working pressure (0.8 bar or thereabouts). The two stroke inlet manifold situation is totally different to a four stroke. When the pipe is not resonating and sucking air through the motor atmospheric pressure flows back in via the exhaust stinger and any other hole it can find. Piston pumping on a high performance two stroke (or any 2S) is virtually non existent compared to a four stroke.


  13. #31873
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    205
    Quote Originally Posted by TZ350 View Post
    Piston pumping on a high performance two stroke (or any 2S) is virtually non existent compared to a four stroke.
    OK, I see that with regard to braking. 2S is just compressing and expanding 'gas' above the exhaust port.
    No matter what the actual pressure, the effect is pretty neutral.

    A compression release on a 2S is effective because the compression work is lost, not returned.

    In a 4S engine on overrun, the pressure is lost out the exhaust valve.
    Probably even more effective as a brake with an open throttle and the ignition killed.

    Cheers, Daryl

  14. #31874
    Join Date
    18th May 2007 - 20:23
    Bike
    RG50 and 76 Suzuki GP125 Buckets
    Location
    Auckland
    Posts
    9,764
    Click image for larger version. 

Name:	Crankcase Pressure Traces.png 
Views:	31 
Size:	370.2 KB 
ID:	341902

    My plan is to measure the difference between the highest and lowest pressure in the crankcase each cycle and use the difference between these readings as an indication of relative changes in airflow through the motor. The more air, the bigger the difference.

    Following pointers from other people, I have found that the pressure sensor transmits the pressure reading in discreet 1 ms steps, ie; every ms it transmits the current value for 1 ms. I thought it was going to be a continuous analog signal but nope, I was wrong about that. 1 ms steps it is, not sure but this might be quite a common approach.

    Click image for larger version. 

Name:	11580 RPM.jpg 
Views:	26 
Size:	739.5 KB 
ID:	341900

    Checking with a scope near maximum rpm I am able to see a distinct high and low pressure reading for each crank cycle, so good to go with my plan.

    Because the pressure transducer and TPS have relativly high output resistances I need to use an OP AMP voltage follower to supply enough current quickly enough to charge the capacitors in the analog input of the EFI's CPU for the CPU to read.

    The EFI CPU reads an analog signal by allowing the analog voltage to charge a capacitor up and the CPU then times how long it takes to discharge. These capacitors have very little forward resistance so the signal source also needs to have little forward resistance to be able to charge the capacitor up in the time available. TPS's and MAP sensors don't, they have relativly high forward resistances and low current so I will need something like an OP Amp to follow the sensors signal voltage and output a low resistance high current signal to the CPU.

    Click image for larger version. 

Name:	OpAmp Output Limitations.png 
Views:	39 
Size:	375.6 KB 
ID:	341901

    My first efforts with an Op Amp were a bust. It took me a while to find out that an OP Amp has limitations. It is unable to completely swing to the extremes of the supply voltage. So a 0 to 5 Volt power supply is not good enough for a 0 to 5 Volt analog output. To get a zero Volt signal out you need a negative supply rail to the OP Amp. I have been able to find some tricky little DC DC converters that take +5V and converts the output to -5V so now using the bikes 12Volt system I will be able to jack up a -5V to + 12V supply for the Op Amp and get a good 0V to 5V analog signal out. Hopefully get to bench test this over the week end.

    This is Buckets, you take a simple idea like EFI, leap in boots and all, find out how complicated it is to implement then learn a shit load along the way trying to make it work....... .... Love It.


  15. #31875
    Join Date
    28th August 2015 - 00:01
    Bike
    1975 Hodaka Wombat
    Location
    Eugene, Oregon, USA
    Posts
    113
    Quote Originally Posted by husaberg View Post
    Lohring i posted a while ago mirco fuel injection stuff a university student was selling Pico or something.
    https://www.popularmechanics.com/car...tors-15682450/
    https://www.fastcompany.com/3004342/...-fraction-cost
    http://spark.annarborusa.org/feature...4Feature2.aspx
    Website under construction, no phone, no reply to email; I think they are not in business. I've checked out several other small two stroke throttle body injection systems as well. So far, no luck. I suspect they don't offer enough advantage over carbs and are higher cost.

    The small IC engines are also in danger of being replaced with battery electric systems. That's pretty much happened in the under 15 cc model engine area and is creeping into even larger sizes as battery costs and weights go down. We'll see what happens with larger, low weight, high power applications.

    Lohring Miller

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
  •