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Thread: Proptype Beagle Bone Black EFI cape

  1. #1
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    Proptype Beagle Bone Black EFI cape

    This is a Fun project that I am working on.
    I have a 98 WS-6 that I am modifying next year.
    I am dissatisfied with current aftermarket offerings for ECU.
    So I decided to build one myself.
    I like the Beagleone platform and have made lots of other complex projects using them.
    The boards are serial and Cam coms
    input interface and output driver
    My intent is a sequential multi port, multi fuel, ECU with a in car Double DIN chassis to replace the old Bose system in my WS-6.
    Touch screen on the fly tuning and a nav entertainment system in one.

    IMG_1439.jpg
    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

  2. #2
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    how much cheaper it will be then Megasquirt witch combined with WB, tablet and Tunerstudio is ? Will it have boost controler, launch control, nitrous control, table switching etc ?

    bets regards

  3. #3
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    Much Cheaper
    I did a project with MS2 V3 module and needed trans control, multi pump fuel pump control, Ac control and Speedo
    So I would have require 3 additional MS2 V3 modules at @250 each not effective.
    ended up using a Teensy 3.6 with the MS2 V3 total PITA took four months to get the code working together.
    In the mean time I saw that the Gokart EFI guys used a Teensy 3.5 with a Arduino Mega adapter for one of their builds. Now called Speedduino cool have not tried one.
    What I ran into with the Microsquirt universe was the low output count and not much documentation on their BIN firmwares that I saw.

    The BeagleBone has a lot more RTC GPIO and if I am going to code Id rather do it on open hardware software.

    One main reason for me is that I was an analog Fuel Injection and Mechanical Fuel injection GURU of sorts back in the very early days of EFI made lots of badass turbo BMW, Mitsubishi, and Nissan using Jectronic Not L-Jetronic we had only exhaust temp for feed back no O2 Lambda sensors. I started with my relationship to GM when the DFI olds and Cadilacs first came out I believe it was @1980 or so. I repaired crap loads of ECU at our carb shop.

    Most of the integration at that time was still analog even though the product was called digital.
    Someone got the idea that a square wave meant digital.

    In the early days each stage of sensor input fed integrators and comparators the Air Flow sensor was a variable resistance mechanism.
    The TPS was not a continuously variable resistance but a stepped switch that the accell curve adjustment was made by different resistors. You could lengthen or shorten injector accell pulse integrator by adding resistors soldered to the PCB.
    JetronicTPS.jpg

    With the advent of micro controllers the idea of approximation tables became normal.
    The reason behind the use of 4-8 bit micros over discrete was that they where easier to mass produce and later change the tables for approximation.
    With analog systems the calculations where absolute and infinitely more accurate when properly tuned.
    In computer lingo the curves require the use of irrational numbers that binary math can not accurately handle the use of floats and longs still approximates to the byte width of the struct analog does not.
    So in the early days of controllers your word width might be 16bit but the processor was 4 bit.
    Because of this the look up table was much faster and the results more predictable.
    Today with 32bit and 64bit word widths we can more accurately calculate the true values.
    For instance Two values that can be correlated to provide more accurate combustion monitoring are the Spark discharge voltage / period and the exhaust pulse temp.
    This is much more accurate than O2 sensor readings.
    The variable frequency MAF and Flex Fuel sensors also provide better linearity than Speed Density "Map, TPS, O2"
    Most of the GM ECU are built with slower than 66Mhz processors a lot more tasks can be done with 1Ghz in the same time window.
    So if I have a V8 at 10,000 RPM it is producing 1334 instance per second giving you 750uS to calculate fuel and spark. Thats 750,000 clock cycles at 1GHz.

    I am really surprised that I have not seen a realtime ECU out there.
    Everyone seems to be using the tables method as far as I know.
    Makes for good industry support not so much for the shade tree or backyard hotrodder.
    I think that this is part of why people are still pulling EFI and putting carbs on.
    Here in florida the fuel is at least 10% alcohol and I have yet to see a carb that works correctly with it.

    So in my EFI the display will not be the FUEL Spark tables that the tuner guys love but a simpler interface that would make sense to a carb guy.
    Idle
    Warm up
    Front pump cam
    Vacuum secondary spring weight
    jet size
    Squirter size
    and the like
    Nice touch screen interface so you can put a "fatter jet" in while driving.
    When not tuning the screen will be a gauge cluster and like a NAV or entertainment system.

    And I have heard that Holley has a little screen that does something similar just not interested in paying such high prices for the name.

    So cost wise the first one is MUNDO labor intensive.
    But the modular design will allow you to use the cape for as little or as much as you want.
    In my first setup I am developing the cape with GPIO set up for my LSX motor in the WS6 so 16 injector control and 8 coils on the output board.
    For the Truck the output board will only have 2 injector channels and a single coil driver.
    The transmission board will be for a 4L60E
    For the Cadillac the input and GPIO board will have a micro controller to make sense of the crank sensors and Cam position as well as 8 injector and 8 coil drivers.
    The transmission board will be for a 4T80E and should be fine for 4L80E.

    SO on both my WS6 and the STS the dash is Cam bus driven so the serial board has this capacity.
    On the truck not needed just a ALDL for codes.


    I am probably open sourcing the whole project and if requested do build to order through Fritzing or similar, much of what I am planning to use is in the Arduino community already.
    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. #4
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    Oh man, I am going to follow this thread. Is this the place you will be updating your progress, or is there another forum or site I should also follow?

    I own a BeagleBoneBlack that I'm hoping to use with MachineKit https://www.machinekit.io/ for a CNC project I'm working on. MachineKit is a port of Linux CNC http://linuxcnc.org/

    Thank you in advance for starting a project like this.

  5. #5
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    Quote Originally Posted by DavidBraley View Post
    Oh man, I am going to follow this thread. Is this the place you will be updating your progress, or is there another forum or site I should also follow?

    I own a BeagleBoneBlack that I'm hoping to use with MachineKit https://www.machinekit.io/ for a CNC project I'm working on. MachineKit is a port of Linux CNC http://linuxcnc.org/

    Thank you in advance for starting a project like this.
    Sure man it's self interest not so much altruism I have a 1998 WS6 in the garage that I need to go through the motor on.
    I have been considering doing a LS376 complete set up but still not really happy with what I have seen out there.
    With my health effed my income has plummeted so I have the skill and the knowledge I am putting it to use.

    I have been fighting with the electronics on my 2002 STS for about 3 years now so it is another candidate for the controller.
    I also have a few LT1 engines in the garage that will need controllers.

    SO the order of conquest is the truck overhaul,
    Then STS heads are coming off to try and find a miss and the rusting grounds somewhere in the car.
    So as I clear out my backlog I will be building more for the aluminum LS1 340CI 340HP in my WS6.
    I got #628 of 628 cars made on the 1997 order so It has a single exhaust outlet and an aluminum block LS1 that all the part number say it's a 2002 LS2 corvette but it is stock factory.
    The car also has a TCI raptor and a full Spohn Tubular chassis from the factory.
    The car is 1.5 inches lower than production 1999 and 6" wider at the rear wheels than the 1999 production.
    2 cars delivered to south Florida in march of 1998 mine is one.

    While I still had my lab closed in December due to Kidney failure < sucks old war wounds.
    I had a Milltronics RH30 sold it to buy a couple of more years alive.
    I still have a Jet 7-48 lathe and a small mill.
    I am converting the mill to CNC as well.
    I have looked at the LinuxCNC I used the python macros to generate Code for my big mill.
    For my HF mill drill I just need two axis and a plunge not really three axis.
    So what controller I have chosen is the BPI-M3 because I have a few of them.
    I have 16 Beagles in the drawer as well but The M3 is so much faster.

    The actual stepper drives and DRO I am using GRBL on a Arduino Mega 2560 and Igaging Ezview DRO.
    The M3 will act as the Controller for the GRBL

    On mine I am using inkscape with a bunch of Macros to generate GCode from Colada files exported from Sketchup.
    For my needs I am drawing the stuff I want to make so work flow is unlike a Machine shop for simple stuff I can use the DRO and the Axis like power feeds.

    The beagles make great GPIO drivers and are pretty well suited for EFI.
    One wonky thing on the Beagles is the Power VR if you use a LCD display cape it works fine but through the hdmi it can only display video in a window.
    The M3 has the same issue.
    The Sunxi and armbian groups DO NOT like the powerVR graphics chip so display graphics are a bit processor intensive.
    Make sure that when you set up your axis drives you are realtime.

    On mine I am offloading the interrupts to the MEGA that way it will work more like a conventional old style CNC.
    Ie G-Code command wait complete next block
    On the beagles Interupts will stop motion feedback so display will "jump"
    You may want to use the beagle as the display driver and use serial UART to Arduino Nanos for each axis that way your motion and limits will not effect the display.
    I am also playing with using a serial to parallel shift register to control stepper drivers as a way to offload motion control.

    One of my guys built a large format 3D printer I still have, He intended to use linux CNC but got caught up in getting the Steppers interfaced.
    The base code works to exercise the axis but it does not conform to any of the linux CNC hardware examples.
    I did not have the time to integrate the difference.
    I seldom have need for 3d printed parts so it has been sitting for four years now.
    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. #6
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    Well, you understand this stuff better then I do. I try my best at the micro-controller and electronics projects I make, but I admit to relying on what others have figured out to succeed at it.

    I'm more of a handle cranker. I've been impersonating a machinist, welder and fabricator now for 45 years? My first job was in a machine shop when I was just starting high school. I have a very modest, but capable shop here at home.

    This EFI stuff is really interesting to me. You will find some very smart and helpful people here. They are even friendly! Which has not been my usual experience with some smart people (or people who think they know what they are doing)... I feel super lucky this place even exists.

    Please keep use up to date on your progress! There is a very cool project here going on right now that lets people read and write to the GM Gen 3 PCM's (like the 12200411).

    Take care sir!

  7. #7
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    No need to reinvent the wheel in this case as its already been done.

    https://speeduino.com/wiki/index.php/Overview

    You can't buy one that's already built but you can buy all the parts and PCB from the company and the prices are very fair IMO.

  8. #8
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    Early BETA of the ignition for my Truck
    Small Cap HEI freestanding EST and Knock
    Been sick and struggling to finish my Truck
    But I needed a EST controller to get out and about.
    Stock tune throwing 60 degrees at idle due to low vacumn and knock sensor going crazy with the exhaust note and roller rockers.
    Very mild slight lobe due to the Heads and Cam

    So runs nice and smooth Timing bypass disconnected runs crazy connected.
    Makes sense original motor was <8 to 1 so even on cranking GM has the timing advance way too high.
    Best manifold vacuum on my motor is around 15 degrees advanced.
    9.76 to 1 max mechanical advance old school would be around 37-38 degrees.
    Dwell angle about 5% at idle and less than 35% WOT

    The calculations are pretty simple and a Arduino Nano is fast enough to do upto 10K rpm.
    Like I said the New EFU will be Modular so the first Beta module is the EST and the circuit to meet the Code 42-43 OBDI tests.
    Screen Shot 2019-09-05 at 1.53.45 AM.jpg

    The schematic shows connections to both the Module and ECM pins
    If you want to use a GM 7 or 8 pin Module with a boosted or carbonated engine just do not connect the ECM side.
    The only really important connection for EFI 1995 and earlier is the PIN R signal.

    EST bypass disconnected my Module will use a preset advance firing the Coil somewhere around 10 degrees advanced.
    Once Bypass Goes High 5V the module fires the coil based on the EST signal both the coil dwell and the Timing are controlled off module.
    Dwell angle on after market coils is how you stretch the the spark duration the one I have is advertised at 225ms with stock dwell and 0.50 plug gap the duration is just a bit better than stock.
    There are a variety of GM 8 pin modules with various dwells with bypass disconnected.

    If someone else would like to make this into an MSD the spark can be interrupted at .293 x Spark duration.
    If you know your coils secondary inductance , primary inductance, primary resistance and the base ignition modules current limitation you can calculate how long it takes for the coil to charge and discharge as a spark.
    The spark can be shut off by grounding the negative of the primary while the spark is discharging the coils energy.
    If you shut the spark off when the coil gets to .707 of it's full charge then recharge the coil it will spark again when you open the ground.
    This will work fine with this EST as the ECM gets its signal from the module pin R.
    On my truck the TACH signal comes from the coil so MSD would trash my tach reading.

    Before the auto flame kicks in I am using the Nemonic MSD for Multiple Spark Discharge not the popular brand MSDtm.

    Stock Chevy truck modules switch from cranking to run at 450RPM.
    Coil dwell changes even if there is no EST it works out to about 3 degrees at idle so this is very week and will cause cols start and rough idle.
    Coil Dwell is preset for Stock GM external HEI coils.

    We used to have a couple of companies that made multiple point replacement plates for the pre HEI points style distributors VERY VERY few people who used them ever set them up correctly.
    Most old timers had a dwell meter and would set both sets of points to get the maximum dwell at idle.
    The correct way to set them was on the machine at 30 degrees at 3000 rpm.
    This is how we routinely got 8-9000 Rpm out of de-stroked small blocks and points ignition.

    Today most HEI coils saturate at about 5800 RPM the LT-1 GenII modules can push MSD tm StreetFire tm coils to about 8000 rpm
    It is the dwell that charges the coil
    In this application I do not need more than 5400 RPM so my dwell settings will drop out around 7000rpm with too week a spark.
    Some one better at coding may be able to play with the interrupt timing and get a faster EST signal out of this EST.

    In my code the settings section has the coil parameters and it calculates the dwell on start up. < change these for your setup.
    The code will also calculate the correct maximum advance for the compression ratio of the engine.
    You must scope the knock sensor and adjust your threshold on my trick the valvetrain and Headers are way above the stock ECM sensitivity.
    I have confirmed that the one wire knock sensor does have a variable signal output based on the acoustic amplitude of the vibration.
    The signal rides on a 2.5 DC bias and max 4V peek to peek only care about the compression part of the signal that is positive.
    On the next iteration I will be using a filter cap to average the spikes as a different way to do the thresholding.
    In my code after the plug fires it reads the sensor for a signal. So if I have ping it will pick up before the next firing.
    The knock signal threshold increases the count then reduces the timing.

    Vacuum advance is great but not really necessary and on low vacuum or boosted applications it can cause problems.
    I have seen that many tuners will map advance to vacuum you get a bit of power this way on mild engines.
    Old School I had a distributor machine and weight kits with springs very seldom did I use more than about 10 degrees of advance from manifold vacuum most often just locked out the vacuum advance completely.
    This EST controller reflects those Old ways.
    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

  9. #9
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    This is fantastic. Most of it is over my head, but I'm using it as an excuse to learn something!

    I truly hope you and your family are surviving the hurricane!

    David

  10. #10
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    Super cool project, I love it!

    I've been thinking for a long time that an Arduino Due might make a good base for a fully open source ECU (open source hardware as well as software) but the BeagleBone Black is probably a better choice. Tons of I/O and way-more-than-enough CPU and storage.

    The Speeduino being 4-channel fuel and 4-channel spark kinda kills it for me - it's great what they're doing, but it seems like they're just one hardware revision away from proper control of a V8. And I want my fuel injections timed with the valve events at idle. :)

    Personally I like the table-driven approach of typical ECU software (especially 2004+ Subaru stuff since it's all 32-bit floating-point) but if you come up with open-source designs for capes that handle interfacing with injectors, coils, sensors, etc, then I bet you'll find other people writing different kinds of software to control it all. Probably including me, eventually.

    Are you using Linux on the BBB, or does it boot straight into your ECU software?

  11. #11
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    Updates to the HEI Electronic Spark Timing circuit

    Code completely rewritten
    Auto adjust for Knock sensor added
    redefined digital IO routines
    reprogrammed the Timer registers
    Now running stable on the bench going in the truck later today.

    Using dynamic array now instead of realtime array loads t ram on startup.
    Auto bypass added for loss of signal etc.

    Added a .1uf cap to the Knock sensor and setup the processor ADC to free run to be sure and catch knock events.

    Screen Shot 2019-09-10 at 10.42.57 PM.jpg

    26 degrees advance at 1500 rpm

    IMG_2206.jpg


    @16 degrees at 750 rpm

    IMG_2208.jpg

    Breadboard EST Module
    IMG_2207.jpg

    My new Engine 5.7L Lt1 roller cam Roller Rockers RaceMaster 220cc 64cc CNC 202/160 Top engine kit DMI headers 3 inch single exhaust.
    52mm TBI salad bowl Racemaster universal 60KV coil NO EGR.
    IMG_2198.jpg


    My truck 95 suburban Lowered 6 inches Torque arm rear suspension.
    IMG_2199.jpg

    New code and Schematic Board layout attached
    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

  12. #12
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    Some other Build Photos
    Fresh Driveway overhaul
    IMG_1449.jpg

    Nice fit on these headers
    IMG_1452.jpg
    IMG_1453.jpg

    Same photo color adjusted so you can see the Torque arm
    When you drop suburbans by leaf restacking you run the risk of breaking the springs due to rear end windup.
    The trick is to mount a bracket to the rear of the housing and bolt on a F-Body torque arm just stops the wind up.
    IMG_1453 copy.jpgIMG_1453 copy.jpg

    Trick CHEAP starter I bought this for my Caprice originally 12 years ago. Still today it's like 40 usd when you go looking for a starter on a small block there was a gear reduction option for the 1995 Caprice POLICE 4.3L tiny motor it uses the same flywheel as all the roller cam block engines no shims needed. I have actually moved the truck using this starter without trashing it.It spins the 5.7L at 500rpm at start up really cool find. The housing is like 6 inches long the motor is 2.75 inch diameter so headers NO PROBLEM.
    IMG_1455.jpg
    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

  13. #13
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    Quote Originally Posted by NSFW View Post
    Super cool project, I love it!

    I've been thinking for a long time that an Arduino Due might make a good base for a fully open source ECU (open source hardware as well as software) but the BeagleBone Black is probably a better choice. Tons of I/O and way-more-than-enough CPU and storage.

    The Speeduino being 4-channel fuel and 4-channel spark kinda kills it for me - it's great what they're doing, but it seems like they're just one hardware revision away from proper control of a V8. And I want my fuel injections timed with the valve events at idle. :)

    Personally I like the table-driven approach of typical ECU software (especially 2004+ Subaru stuff since it's all 32-bit floating-point) but if you come up with open-source designs for capes that handle interfacing with injectors, coils, sensors, etc, then I bet you'll find other people writing different kinds of software to control it all. Probably including me, eventually.

    Are you using Linux on the BBB, or does it boot straight into your ECU software?
    On the BBB its linux I assemble my own distro packages for other projects so I will prob do the same here.
    Keeps rev control in house so stuff doesn't break from updates.
    I am liking the QT5 stuff I have played with although it is another learning curve.

    Had encephalitis in 2015 whole left hemisphere was infected so to keep my wits I compiled from source an entire Linux OS over the year.
    I still have issues but the coding keeps me busy while I am having problems.
    I am also in 2-3 stage kidney failure so if I exert myself to do something I pay for it for weeks of pain.

    The truck overhaul only took me 10 days to complete the mechanical but I have not completely recovered after 4 weeks.
    So I sit and wait for the lactic acid and other toxins to finally leave my body.
    No one who has not experienced it could understand it really really hurts not any one spot but the whole body.

    I am a very large guy before I got sick I weighed 260lbs with a 34 inch waist 60 inch chest.
    I lost 40% of my muscle 76 pounds of muscle.
    I have gained back about 50 since the beginning of this year.
    SO I go 250 with a 38 inch waist.

    The electronics and programing keep me level.

    As far as the look up tables I am not a fan I know the formulas and they are not that complex.
    I started in Fuel injection in the early 70s when Hilborn and Chris Victor still came out to help you at the track Dick Morroso Sr was just a guy with track on his farm.
    Gulstrand Mosler Garlits Iskedarin and many others where just guys at the track.

    We had a carb shop called E&D carburetor I was the D fuel injection was mechanical.
    All the same stuff you see in a table is pretty easy to do with hardware.
    The hardware is infinitely more accurate.

    The issue is that software can not do irrational numbers well and every calculation on a engine is an irrational one.
    Meaning there are no integers in the products of the calculations so you have to approximate to use tables.

    For example the quad calc ((-b ± sqrt(bČ - 4ac)) / 2a generates half of a parabolic curve you can find every torque and horsepower curve within an arc segment of this type of curve. IF bČ - 4ac results in a prime such as 1 2 3 5 7 11 the product of the SQRT will be irrational.

    The old analog mechanical and analog electronic systems have no problem calculating these curves real time not so much for binary digital.

    The look up tables come from very slow processing days and just have never been abandoned I think one reason is the guys I went to school with in the 1960s where already in their forties and fifties. I have only a cursory remembrance of programing analog state machines at Pen state in 1969 - 1972 but they where idle for nonlinear and irrational calculations.

    One of the small advantages of the use of tables is the predictive possibility of N-alpha way of tuning but almost all tuners including myself love closed loop and there is a delay in speed density making it reactive not predictive. You have to wait for the last cylinder or last cam sync pulse or the O2 or the thermocouple change that happens after the cylinder has fired.

    I have intended to use some tables like in the EST but load the variables at boot and generate them at startup.
    This lets you make changes and implement them at key cycle.
    For instance on sequential fuel injection your reactive update takes one full revolution to implement anyway.
    The fuel injector firing is best done twice per revolution pulse after the intake closes and again when it first opens.

    I also love waist spark on turbo motors at higher RPMs with a scavenging cam you can actually increase exhaust manifold pressure and boost. Done this recently.

    So instead of a MAP/TABLE metaphor I intend to allows fine adjustment of the variables that go into calculating the values.
    As an example I wrote a simple idle start up routine that sets the knock sensor threshold on the EST automatically.

    Setting up a Hilborn system I used something called a magnahelix to measure actual air flow and a barometric valve to measure air density the proportional fuel valve was linked using an adjustable lever ratio. The old mechanical corvette systems had a bellows that did the same thing the Mercedes jectronic pre lambda used a 4.75 inch diameter flow valve to measure the incoming air flow. Today MAF hot wire measure the rate at witch a known resistance heats and cools to calculate air flow. I made a electronic magnahelix using two MAP sensors and a a venturi tube that actually give better readings than a MAF.

    Another very cool thing I have been thinking of is using the reflected load on the individual coil paks as a way of getting faster feed back of combustion.
    I need to find some very fast ADC samplers something that can sample in the 25MHZ range. To get all the data there. My old analog scope needs some rare Tubes so I have not seen the old spark profile for a long time.

    On the arduino DUE IDK I recently bought one off DX and played a little with it for a tool I am making to read GPS and accelerometer data to calculate horse power drag and torque. I switched to a nano and an accelerometer for a dash mounted lateral G and Horse power gauge. The due is interesting but I had some issues with polling I think might be related to the IDE rather than the processor.
    On the beagle there are some short comings as it is a System on a chip and even though there is time slicing it is not realtime. As a work around I intend to use task specific processing in each of the modules like this EST I think my new rule is if you need to interrupt use a dedicated processor. On the LSX I may just use atmega8 processors for each coil and injector pair IDK yet I have to look at the Timer control on a few of the development boards to determine which I will use.
    I have used teh Teensy controllers lie the software end not so much on the hardware end. Very low current in my application I had to use driver FETS on all of the GPIO of the teensy the current listed is 250mA total that is extremely optimistic after 50 minutes of 40ma I burned one up the actual spec is more like 50uA per port of 8 pins not the voltage regulator rating of 250mA.
    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

  14. #14
    Fuel Injected!
    Join Date
    Jul 2019
    Location
    Orange, CA
    Posts
    54
    Very cool to see the Arduino platform used as an ESC. Since this is an LT1, you wouldn't happen to know the pinout of the ESC module on the LT1 PCM, would you? The 8-pin connector?

    Following along for updates as well, I love all the custom engine control engineering going on on this forum!

  15. #15
    Fuel Injected!
    Join Date
    Jan 2018
    Posts
    28
    Sorry to hear about your health issues, that sounds like a tough burden to bear.

    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.

    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. :)

    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?

    What information can you get about the combusion from monitoring the coil packs?

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