12 L
        I woke up with an idea. No mass air flow sensor. No maximite
        required. Use a potentiometer that is geared to the throttle with a
        small cog belts. Put 5 volts on top of the pot.

        Or you can use a leaner pot with a slide throttle.

        5 volts wide open zero volts closed.

http://www.sdp-si.com/products/miniature-products/miniature-belts-and-pulleys-inch.php <http://www.sdp-si.com/products/miniature-products/miniature-belts-and-pulleys-inch.php>

         Then use my one chip $1 555  EFI.

        Super low cost super simple TLC 555 based electronic fuel injection.


        <http://www.rotaryeng.net/simple-cheap-555.html <http://www.rotaryeng.net/simple-cheap-555.html>


        You can use a low cost Harbor Freight Voltmeter to monitor the pot
        voltage..

        There is no system EFI or carb that is lower cost.

        Paul Lamar


        Paul,

        That is a throttle position sensor TPS

        Why not put a pot in the cockpit at the rotation pivot of the
        throttle lever?

        Kinder environment



        Joe Berki

        Paul,

        Jst  a thought about eliminating the MAF.

        Do we lose altitude compensation?

        Joe Berki

        Yes. But when you take off at a high altitude airport with a carb
        equipped engine you must adjust the mixture anyway.

        The mixture pot can increase or decrease the voltage applied to the
        pot connected to the throttle and then the  555 at any throttle
        setting.

        This is a quick, dirty and low cost  EFI way of getting your engine
        running. You fine tune it with the mixture control just like you do
        any carb equipped aircraft engine.

        Paul Lamar


       My Continental IO-360s have mechanical FIs that simply meter fuel
   into a common injection spyder based on throttle position. This fuel is
   then equally  divided (based on pressure) to individual fuel
   injector/vaporizers located in each intake manifold.  (GAMI injectors
   are tuned per cylinder).  Fuel flow is further moderated by the manual
   mixture control, which is used to lean for cruise, high altitude, and to
   shut down the engine.  Simple and reliable.

       It would seem that Paul’s 555 system triggering off of CAS (using
   RPM as a proxy for power and fuel requirements), moderated by a manual
   mixture control, might well be the simplest solution for our EFI?

       BTW, considering the space restraints, potential damage by a broken
   belt, and mounting considerations of front sensors, might it be more
   practical to mount Hall effect sensors on the redrive adapter plate and
   have a magnet strategically located on the flex plate instead?

       If we will be using Maximites to control the ignition, the current
   $56 color Maximites have an empty breadboard area that could also house
   the 555 EFI circuitry.

       Scott Gettings


        On the question of eliminating maf and  using map, you asked if
   you loose altitude compensation and the answer is you don't have too. I
   am not familiar with the maximite but I am sure it can be done just like
   a megasquirt we use a air temp sensor  and two map sensors one for
   barometric pressure and one for engine manifold pressure. So with having
   barometric pressure and air temp the computer calculates the density
   altitude and gives you altitude compensation. I am confident Paul could
   do the same with maximite, also the tps is really not needed for
   aircraft but I like to have it.


    On most after market ecu's the tps is just used like a accelerator
   pump on a carb and flood clear mode so if you give it full throttle
   while cranking it shuts off the injectors. Its nice to have tps but not
   necessary you can do map based acceleration so if it senses a rapid
   change in manifold pressure it gives it a extra squirt of fuel, but with
   aircraft we don't need rapid throttle response.  As much as i like the
   idea of using a mass air flow sensor there sensitive to moisture so you
   need a good air box to eliminate water ingestion in the rain and with
   everyone wanting to have control over the mixture with a pot or
   switching maps I think a maf is a waste of time and complexity unless
   you were going to do single lever control with different target egts or
   afr per power setting. That's just my thought, I am still considering
   using one myself.
   Thanks, Jacob Sturges

   Doesn't the MAP sensor take care of altitude changes?
   Murry Rozansky


Doesn't the MAP sensor take care of altitude changes?
Murry Rozansky

   Yes it will but from my experience I like air temp and a second map sensor for baro to maintain the targeted air fuel ratio better on your way to altitude then you don't need a mixture lever, with those you can tune it to do whatever you want it to do and reduce pilot work load.  I would still have a pot if needed and then make tunning changes on the ground, that's what I am doing with the megasquirt right now for the lycoming but i am hoping to tune it well enough so it hits what afr i want for what manifold pressure i want and i might still leave a lean/rich knob or just burn new map in the air with 2 pilots cause we have mechanical fuel injection and mags for back up during testing and maybe permanently. It sounds to me though that you just want to manually lean it and control your air fuel yourself which then just map sensor will do, but air temp is nice for cold start and specially if your turbocharged you can richen it up if the air temps get hot for safety too.
Thanks, Jacob Sturges



The Rotary Engine free News Letter. Powered by Linux. If you want off
the list PLEASE let me know and I will remove  you.  ACRE NL web
site. http://www.rotaryeng.net You Tube http://tinyurl.com/beqqxas
Copyright 1998-2017 All world wide rights reserved.