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Thread: Proptype Beagle Bone Black EFI cape

  1. #16
    Fuel Injected! vilefly's Avatar
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    I think I can answer the coil monitoring question, assuming I have a clue as to what will be designed (which I don't).

    Not sure if it was intended to go Ion Sensing or not, so I will stick to conventional scope patterns that can be picked up on the primary side with a little work.

    scope pattern interpretation sample.png
    This is only a 1/3 the info you would find out. This is just an example.
    Hope this helps. Ion Sensing would give more data, for sure, but under 4k rpm I think.
    Last edited by vilefly; 09-13-2019 at 02:57 AM.

  2. #17
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    11Dec update

    Sorry for the long delay I have been pretty sick.
    Tonight I took my first test drive with the new fuel injection system and trans controller.
    Ran really well
    Raining so I had some serious tire spin 130mph just pulling away from light.
    Ran it over to the gas station and put some gas in recorded the trip back.
    Attached is the raw log from the trans controller.
    I haven't figured out the PCS 3-2 TCC PWM modulator stuff.
    This trans has a shift kit in it from an unknown source and unknown mod.
    So I do not know if I will even use the PWM stuff on this build.
    I have giant torque from the new motor and I Torque arm on the rear end so I don't think I mind the heavy shift feel.
    The ProtoType EFI controller is now stable and running well.
    The Auto tune function needs some work the EEPROM library from arduino does not have any error handling.
    Also write time for the library is really slow I may rewrite the Software library to get better speed from an external Fram or Mram NVRam chip.
    So currently I have the trans and EFI running on my own version of a Mega2560 controller
    The code for the trans will run on a leonardo Atmega 32U4 just fine.

    The code base shares nothing from the GM or Megasquirt methodology.
    Been trying to keep the Carburetor metaphor to make it easy for the every guy to understand.
    NO Volumetric efficiency tables, Not N alpha either.
    The metaphor works like this;
    The engine is an air pump you can roughly estimate the weight of the air in the cylinder using the Ideal gas laws.
    Didn't bother with the remolds numbers or flow dynamics "Turbulence" I really like using HUGE heads for any of my builds and less cam.
    The engines flow more air but usually stumble really badly with Carburetor like a tunnel ram on a small cid engine it will make a lot of power but good luck trying to drive it.
    I use 220 CC intake runners with .477-560 lift 260 duration 114 lobe centers 220 intake 192 exhaust heart shaped angle plug heads.
    So not much idle vacuum so when the throttle is opened manifold vacuum drops rapidly.
    Also you have to run a free flowing exhaust or the exhaust reversion from back pressure kills all the gain.
    This config makes an easy 400Hp Na and I have done a few boosted to mid 800 at flywheel on turbo you have to run rich and use waist spark to bring turbine up to speed faster also smaller trim than whats popular. I started turboing cars using diesel cartridges in the 1970s. As for super chargers Dyers and Lanthams were on Chrysler garbage trucks but you basically had to steal them to get one. I had a buddy Red Walker who built a Blown V6 made the cover of hotrod magazine in the early eighties or late 70s I managed to convince his dad to trade my work for a 671 back then.

    On my EFI I average the manifold vacuum and use it only to select a range so the part throttle MAP drops 30-40 % on tip in but it takes about 240ms to change out of the fuel range.
    The TPS is averaged 1 of 10 at 1.2ms between samples the TPS Delta Over Time is used as a direct multiplier for the enrichment pulse.
    So it acts like the jumbo Holley Q pump for tunnel rams.
    https://www.carid.com/holley/50cc-ac...mpn-20-11.html
    The lean bog on tunnel rams comes from no vacuum signal at the power valve port to draw the fuel over the bowl height you have to dump a crap load of fuel into the cylinders at tip in to equal out the increased amount of air weight in the same volume at higher pressure.

    So TBI EFi works much better to do this and I have had difficulties tuning this with both Cats, Megatune for OBD and Tuner Studio for MicroSquirts.
    On my EFI system the accel tune is accomplished with a hand held 5 button switch to use while driving.

    Since the current controller is a Atmega 2560 so I could use the free Arduino Code base I am using a very large single table MAP by CLT 42 x 39 cells this covers each of the plateaus of stability with regular air. Air density therefore weight is not exactly linear it is a compressible mixture and even at sea level there are stable ranges that air exists in. I remember that the physics books claim that curves are completely linear but then there is the whole additional field of fluid dynamics that deals with the nonlinearity.
    So according to CLT and Map a base fuel byte is selected this byte represents the weight of the air in the cylinder / the Air fuel ratio.
    This byte is multiplied by the JET Factor this number is based on the actual flow of the TBI on the engine.
    Going from the advertised flow rates of my GM TBI mine should have been 0.008 after some tuning mine is 0.05225 so the advertised 60lbshr is not correct mine is more like 20LbsHr Thats fine for this truck I rev limit at 6000 but will never run it above 4500. That gives me like 3.3Ms to squirt between firings. At idle I am currently running about 210 to 280 us. At start 900 to 1200 on a cold day.

    After the Jet factor I multiply a trim from a table stored in EEPROM one byte 0% to 250% of calculated fuel demand. The table is MAP times RPM and while the Auto tune was running I saw that it fattened up at about 2500RPM like I expected for the Dynamics of the High rise Intake.
    I am uncertain if the EEPROM library just writes too slow and collides with the next firing pulse or the EEPROM cll is bad and it faults.
    With the research I have done so far I understand that the default library erases first then writes even on update this is not necessary for a single byte write so I will have to change that.

    The algorithm for the calculations is pretty close to done I will at some point in the future port the code over to a free standing application to run on the BBB.
    On the BBB I can just run the calculation RealTime rather than use the spreadsheet results as a table.

    I will post a full package in the next couple of days.
    Attached Files Attached Files
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

  3. #18
    Fuel Injected!
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    Running New EFI System and 4L60E controller

    Here is the Package on my desktop that is running the truck now.
    I will post a revised as I gather the mods and finish documenting the build.
    TBI EFI running fine with GM TBI
    Trans controller mostly working
    Attached Files Attached Files
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

  4. #19
    Fuel Injected!
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    Quote Originally Posted by PeteS View Post
    No need to reinvent the wheel in this case as its already been done.
    Yep For a mazda Miata with a crank trigger using Tunerstudio it's A Nice Job started following them when they called it GOcart efi or something like that.
    However Although I am proficient with TunerStudio MegaTune and Cats tuner I really want to get away from the whole tables IDEA my intent is to design and build and actual calculating system, But for starters I needed to build something that would work with my favorite engine build. I have had limited success with Cats tuner using GM66ECU on LT1 but have had to compromise way too much to use tuner studio on different builds.

    I finished a Crossfire corvette MicroSquirt integration two years ago and it was pretty much miserable the outcome was good but the Microsquirt ala Tuner Studio works best with what it was designed for a crank triggered 4 cylinder.

    I have seen the huge push of conformity to a most popular set of parts for engine builds.
    I seem not to conform and Have built crazy huge power with cheaper less common parts over the years.

    Once I get my Mill set up again I intend to start building a LT1 using modified Gen1 SBC heads and either 4 tiny Turbos or 4 AiSan 30CID Screw Compressors.
    These are the little compressors with the AC compressor clutch pulleys.

    I also am thinking about fitting a Later model M122 blower to my STS cadillac.

    As far as the wheel invention like I said I am not really satisfied with whats available and have the skills to do this.
    The other thing is these available options are not really suitable for easy rapid adoption for a typical home garage mechanic.
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

  5. #20
    Fuel Injected!
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    Quote Originally Posted by NSFW View Post
    Sorry to hear about your health issues, that sounds like a tough burden to bear.
    Yep lived longer than anyone else I or my doctors are aware of.
    I currently have only 1/3 of one kidney I have to watch everything I do and avoid toxins like crazy.
    Still sick for days at a time. But 7.5 years beyond terminal

    Quote Originally Posted by NSFW View Post
    I wouldn't worry much about irrational numbers, since the 32-bit floating point system gives lots of precision. And if you really want more you can use 64-bit ("double precision") with a small performance penalty - but with something like the BBB, there's probably still going to be plenty of CPU power. The time periods between sparks or fuel injections are long enough to do a lot of math.
    Yep current math with TWO big tables and 4 sensors works out to about 500us on my BETA prototype.
    The issue with 32bit is that most of the floats are significant out nine or more points.
    The MOC921 and The Atmega series are significant out seven points.
    The Atmega has no hardware division so you have to invert and multiply and that is where the float precision is lacking.
    The cross table 3d map would best be calculated in a vector unit rather than iterative like current offerings.
    Nvidea and Motorola have Vector processors but cost prohibitive.
    EVERY thing else is iterative including all the bitcoin basics and high end graphics cards.
    Even the Xeon PHI that I have written much for is iterative while still in decent health I used to build extreme High Performance Computers.
    Not High Availability Clusters but unified backplane HPC last one I designed and built was in 2016 with 608 64bit processing cores and 96Tera Byte of bandwidth on QPI busses. It placed 375 million voice mail messages in 4 seconds for a political ad campaign.

    Quietly the BBB has a much maligned PowerVR vector processing core the popular boys and girls have chosen the favorite Mali core for its ability to playback Mp4,MSMP$ and MKV full screen. ALA PI series.

    I have used these BBB just for the vector unit for calculating 4 billion unique 2048 character pallandrom prime numbers to use as RSA keys.
    I made a small cluster using a modified version of the PAPERS protocol for task scheduling on the hardware,

    Quote Originally Posted by NSFW View Post
    One of the nice things about lookup tables is that they make it pretty easy to visualize what's going to happen in the engine. With RPM on one axis and air on another axis, you can immediately see what the spark timing will be, or what the AFR will be, and you can see how those values will change in response to changes in RPM or air. I'm intrigued by the idea of using math instead, but in order to get my head around that approach I'm sure I'd have to start by using that math to populate a table to look at. :)
    Yep thats conditioning I do the same thing I wrote into the prototype a couple of screen print routines so I could see the tables.
    ViEWTABLES lets you see the MAP VS Coolant table
    CT lets you see the crazy tables prints out Temp x MAP x RPM
    EEPROMDUMP lets you view the self tune and create the final trim lookup byte array.

    Quote Originally Posted by NSFW View Post
    If I'm reading you right, you're going to use the BBB to come up with a schedule of fuel and spark events, and then use a peripheral processor to trigger the injectors and coils according to that schedule?
    Right now yes I have been unable to find cheap openly available addressable 16bit timers the ATmega series so far seems to be working with hardware integration nearing complete. The metaphor is much different than Tuner Studio or MEgatune mainly because I always feel held back by less than optimal knowledge of the software suites. One pet issue I have is that the tables seem way too small for what I know other EFI use 12x12 16x16 or 8x8 for the table pitches my minimalist table is 1600 cells. I watched the address stream at idle making changes to about 30 cells this detail is not available on currently offered products. I came from the mechanical fuel injection world and not just repaired but designed and built mechanical fuel systems in the early days. All analog digital is an approximation of infinite variability.
    Specifically the PowerVR graphics processor of the Beagle and the A83T lets you calculate the actual vectors and curves like the reynolds numbers that make up the Volumetric efficiency curves that are approximated by the tables.



    Quote Originally Posted by NSFW View Post
    What information can you get about the combusion from monitoring the coil packs?
    This si great,
    In the early days upto recent no one had actually photographed a flame front expansion or ignition in a combustion chamber so there where many competing theories.
    I probably will screw up who owned what but the theories
    One I think Champion believed that ignition occurred when the spark plug shed minute particles of metal and the combustion began as a thermal process.
    Another was that the physical blue corona discharge actuall caused the ignition Mallory,MSD,Accel,GM,and many others.
    Another believed that it was the heat of the flash Ford,Autolyte etc.
    A guy named Christopher Jacobs believed that is was similar to lasing action that once the total energy level exceeded the latent heat of covalence that ignition began so if energy in the cylinder exceeded a certain point the shift on the collapse of the electron clouds around the atoms would cause the cascade and the resulting drop int covalent bonding to a lower latent heat giving off the energy present in the chemistry through combustion. HE was correct and proved it by fitting microwave transducers to an IROC camaro back some time ago once started you could run any fuel.

    New material science and faster cameras allowed true inspection if the process to take place in the 1990s

    When I first studied the process I was taught how to use a Sun Scope analyser circa 1968 or so.
    Had a very high resolution scope with a giant rear projection screen.

    Every material known to man has a diamagnetic threshold and a dielectric threshold.
    This its the break over voltage that is reached when looking at the scope dry air has a dielectric of 50K ohms per inch.
    Each fuel mixture has similar ratings old 113 octane at 14.7 to one at .o35 inches was 12KV <-- rich lean
    The rate of dissipation from the peak to the 70.7 percent of peak gives you the total volume of the dielectric <-- cylinder fill
    The bottom peak minus 70.7% gives you burn completion time <--MAP LOAD
    The ring at the bottom and the known coil impedance gives you a number proportional to ideal timing.

    So the coil is a device typically an autotransformer that the secondary condition is reflected into the primary so you need not measure the high voltage side just the primary the high voltage side will be proportional to the primary measurement.
    Automotive grade coil driver packs do every thing they can to isolate this and do a good job but all you need to get a precise low voltage scope trace is a .1 ohm resistor in primary series and a differential voltage follower.

    So in short from the spark coil primary we can more accurately measure in cylinder Mixture Timing and Load by measuring the exhaust temperature we can calculate the total oxygen in the combustion. This can allow only the throttle position exhaust temp and coil primary to be the complete sensor feed back for an OPEN dynamic closed loop system.
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

  6. #21
    Fuel Injected!
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    March 5 2020 Updates

    I have been running the last rev of Board and Software in my truck for a couple of months now.
    Three issues I know of
    Idle Control sucks < known the time for the idle motor to actually change the idle is too long addressed it differently in the next rev of hardware.
    Random Communication error -<<< big one occasionally the I2c gets interrupted by the ignition interrupt and either the trans controller crashes or the fuel crashes. Lots of fun when under hard accel it stuck in second and I hit the rev limit built into the pulse filter. Turning ignition off and back on resets the controllers in next rev of hardware I approached the whole coms thing differently. Using a single hardwired byte to convey O2 tracking for closed loop and analog distribution amplifiers to communicate Map TPS RPM and MPH between the modules. The Hardware Rev after the next I have moved all calculations off the timing controller so that only the injector pulse timer and the ignition pulse are being dealt with. On this next rev I am still calculating the RPM from interrupt period on the fuel pulse controller. It is not necessary to do so one rev three I am using a Frequency to voltage convertor to provide a RPM signal then calculation the air fill weight from Map, CLt and overlaying a Feed back Map based on RPM, Map and O2 feedback.
    Trans shifts way too conservative. <-- this is just a preference kind of thing, the trans I have in the truck had a "Shift Kit for Towing" installed I have no change in Line pressure when modulated and no change in Torque convertor feel when modulated and no change in 3-2 downshift so I am only guessing that they bypassed accumulators and line pressure regulation at the valve body plate like the old B&M shift kits plate for 700R4. However my code tends to upshift sooner than I really like but I guess that it saves gas. In next rev I intend to have a higher shift point. I also am incorporating a mode switch and flappy buttons function to the trans controller.
    Biggest change on next version -- direct calculation and no table for base fuel I worked out a pretty stable calculation that takes @470us and it is broken down into 8 separate parts so the base fuel updates every 2 rotations. This is actually faster than table lookups and eeprom reads. BTW atmegas have no division in the processor so all maths have to be iterated subtractions. However the hardfloat does seem to work so multipling a floating point does work pretty quick. So divisors are calculated and stored as const float at start up and used by multiplying.
    I will be posting REV 2 drawings and Code in a few days, I drive truck every day but am pretty sick and have long periods of non-function.
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

  7. #22
    Fuel Injected!
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    Fantastic!

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