PrevPrev Go to previous topic
NextNext Go to next topic
Last Post 08 Mar 2015 11:19 AM by  Reanimotion
MSExtra Thread Summary
 10 Replies
Sort:
You are not authorized to post a reply.
Author Messages
Reanimotion
System Designer
Basic Member
Basic Member
Posts:125


--
08 Mar 2015 11:09 AM
    the following is an extract of the thread we created on MSExtra.com

    Wed Jul 09, 2014 4:41 am
    I've been running a microsquirt in the car for a couple of years now to drive the CANbus instruments and accessories transplanted during the original build.
    During the planning of the refresh I thought "Hey, why not EFI?"

    Well after some research, I then chickened out as the CIS system is working fine, but the silly side of me then thought "Hey, what about a digital WUR?"
    A few weeks of internet research later and it appears the small number of previous attempts by others have either had flaws in control or execution or failed to kick off.

    So with a mechanical design in hand and a Microsquirt in the vehicle, the logical conclusion of using the Megasquirt family for fine control to eliminate flaw #1 just seemed to make sense.

    Coding has begun and is looking good so far.

    PWM 0-100 on Inj 1 for K-Jet
    PWM 50-100 on Inj 1 / 49-0 on Inj 2 for KE-Jet
    **************************************************************************
    SpareADC for WUR CP > 5 Bar
    Barometric correction not required as system is naturally MAF in air plate
    Injector at constant duty with variable PWM closed-loop referenced to kPA/CP linear table and proportional adjustment referencing req_pw1 from VE/pw calcs in MS

    Mad? maybe <img src='http://www.frankencis.com/DesktopModules/ActiveForums/themes/_default/emoticons/smile.gif' align="absmiddle" border="0" class="afEmoticon" />
    Useful? probably.

    works? definitely!
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:10 AM
    Fri Jul 11, 2014 2:43 am

    for what it is CIS is quite a brilliant system and it seemed a shame to throw it away.

    Ok, base coding for K-Jetronic is done and running in closed loop with simulated inputs.
    Control Pressure targeting is rock solid and fast to respond so I think its ready for system tests
    INJ1() and INJ2() have been modified to switch between normal operation and PWM/Duty modes depending on the injType setting in the tune
    page4_data.InjType, 0 = port injection / throttle body
    1 = K-Jetronic/CIS
    2 = KE-Jetronic/DPR

    additional code has been added in parallel for PWM/Duty calculations based on the CP map in the first post above and some initial settings on the injector page

    I'll be running an in house custom made metering block with ~120hz pulse width modulation of a single fuel injector for pressure control
    This operates in closed loop with a 100psi digital pressure sensor and a target pressure varied by the MS final VE target.

    As K-Jet handles the mass air changes the VE tables can start flat at 100 and then essentially be operated as an interceptor by adjusting +/- the 100 base wherever needed.
    As the Bosch WUR (Warm Up Regulator, and an understatement on what it really does) references engine temp and manifold vac., The Warm up enrichment in MS could be replaced by or mixed with the control pressure base map, and the load axis of the MS VE table will replace the manifold vac function of the WUR. We also now gain the RPM axis and all the other MS tuning options.
    Accel enrichment etc. from MS is definitely now valid but must be considered in conjunction with the K-Jet feature of acceleration enrichment at the fuel distributor due to the air metering plate over-swing.
    Decel-Cut and Fuel-Cut on limiter has been coded for but is really a KE-Jet only facility
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:12 AM
    Fri Jul 11, 2014 6:19 pm
    I don't have a CIS-E system or DPR here at present so I'll be doing the CIS-E code last - volunteer test subjects most welcome
    From the specs I can find the DPR is 19ohms, and probably driven PWM with some form of series load in the bosch ecu, as without it duty at load would have to be around 5% or less to get down to the specified current.
    DPR 19 ohms pwm (at 100hz?) with an unconfirmed range of 0-140ma with normal operation between 10-35
    roughly rounded, 19ohms at 12v gives 600ma and at 13.8 gives 720ma so starting duty to get 40ma would be 40/720=0.055556 or around 5.5% duty
    an additional 160ohms in series should bring it to 33.5ma at 50% duty so the factory DPR operation range would need to be established to choose a suitable series load.
    The reverse polarity only seems to be for fuel cut so I'm guessing the planned INJ2 output and the H-Bridge setup could be ignored completely if deceleration/rev-limit fuel management was not a priority
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:13 AM
    Fri Jul 11, 2014 6:34 pm

    Actually - thinking about it further - I think the current limiting might be possible in code without too much fluffing round via dual frequencies on the Injection driver similar to the Peak/Hold setup.
    depending on the driver something like this should be possible.
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:13 AM
    Sat Jul 12, 2014 2:39 pm

    OK,
    Coded for closed loop PWM control with a VE to kPA target pressure at 0.1 kPa resolution and it seems to be running well on the bench.
    i'm still hunting through the MS2EXTRA mixture code and getting lost a bit with all the tmp1/tmp2 variables have I missed any obvious modifiers? or compounded any?
    Ive got Gamma / Fuel (Flex) / EGO and I think I'm still looking for a way to nicely do % accel enrichment although K/KE-Jet has a built in compensation via the MAF plate overswing on rapid airflow changes so it may not be necessary.
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:14 AM
    Sun Jul 13, 2014 12:28 pm

    K-Jet won't need accel enrichment but KE-Jet will so accell will have to be integrated as a % rather than the current additional time in ms
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:15 AM
    Sun Jul 13, 2014 3:09 pm

    My thoughts are, both systems overshoot but.
    K-Jetronic also has a drop in control pressure as vacuum drops lowering the force against the piston and therefore the plate and allowing a larger movement
    KE-Jetronic is constant pressure at the piston so the overswing would not change for load or temperature, the ecu then compensates.
    so with that in mind even if we don't need it, It would be sensible to bring it in to the calculation, just set accel enrichment to 0 as a baseline and tweak if needed.

    What I want to avoid is losing features from either CIS or MegaSquirt, unless one replaces the other or the concept is not valid e.g. MS Cranking settings for the K-Jet
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:15 AM
    Mon Jul 14, 2014 3:48 am

    Coding done for the MS2 and Microsquirt sans accel enrichment at the moment.
    DPR +- across INJ1&2 seems to be working fine as well. (no dual frequency current control yet i.e. pulsed highs within the main duty cycle)
    I've done the DPR code as a pure final VE from MS to PWM steps in the same 0.1 resolution, so
    - 100% VE equates to no drive on either channel,
    - over a hundred increases drive on INJ1 leaving INJ2 at 0,
    - less than 100 increases drive on INJ2 with INJ1 at 0
    This will then need a H-Bridge driver or patching to the stepper idle chip on MS2 if it can handle it
    K-Jetronic stays as closed loop control pressure targeting with VE to kPa translation

    So in theory we have K & KE Jetronic capability with MegaSquirt.
    It will be a couple of weeks before the prototype metering block can be run through CNC and we can run on to vehicle testing.

    MS3 might be overkill in this application but the process should translate.
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:16 AM
    Mon Jul 14, 2014 6:25 pm

    apparently functional but definitely "light fuse and stand well clear" version about to be real world tested
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:16 AM
    Wed Jul 16, 2014 1:34 am

    project updated

    should now form a decent basis for
    K-Jetronic with Digital WUR on INJ1
    K-Jetronic - Lambda with dual maps #1 for Digital WUR on INJ1 #2 for Frequency Valve on INJ2
    KE-Jetronic - control of DPR (INJ1 for forward/rich and INJ2 for reverse/lean via H-Bridge)
    Reanimotion
    System Designer
    Basic Member
    Basic Member
    Posts:125


    --
    08 Mar 2015 11:19 AM
    http://www.frankencis.com/wiki/Arti...S-Firmware

    CIS-E requires our hardware interface between the DPR/EHA and the MicroSquirt


    Sun Jan 11, 2015 4:13 pm

    The firmware is compiled for MicroSquirt, and has not been tested on an ordinary MS2
    so you may be best grabbing the source and recompiling
    similarly the INI file is uSquirt only and must be adjusted to match the MSII
    You are not authorized to post a reply.