injector drivers

[John Dammeyer]

Hi Bruce,

OK.  I if I under stand this correctly,  my algorithm should:

a) Determine that TPS has changed.  The amount of change suggests the
degree of enrichment on the PW.  Start a timer,  user configurable
during engine tuning or perhaps also  based on delta TPS.

b) Start checking delta MAP and when it stops changing, (within some
guideline),  back off on enrichment.

This would suggest, for example,  if engine at 14.7:1 and throttle hit
hard,  that an initial change of PW to give 10:1 for a time interval.
Then,  reduce to 12.6:1 once MAP sensor shows a change.  Then,  as MAP
pressure reaches steady state back PW off until 14.7:1 is reached again.

I'm in a situation where I have a fluid load (propeller) on the engine
so at some point I will have WOT, maximum airflow at some RPM with
hopefully a Ve approaching 1.

Thanks,

John

-----Original Message-----
From: Bruce Plecan <nacelp at bright.net>
To: diy_efi at efi332.eng.ohio-state.edu
<diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, March 07, 1999 4:50 PM
Subject: Re: injector drivers


>
>-----Original Message-----
>From: John Dammeyer <johnd at autoartisans.com>
>To: diy_efi at efi332.eng.ohio-state.edu
<diy_efi at efi332.eng.ohio-state.edu>
>Date: Sunday, March 07, 1999 4:52 PM
>Subject: Re: injector drivers
>
>
>Delta TPS, and Delta MAP, both corrected by coolant temp., are common.
>Bruce
>
>>I'm building a ignition/injection system for a Honda 1595 CC engine.
So
>>far the CD ignition works great as do all the appropriate sensors like
>>the MAP/Air Temperature etc.  I'm wondering how to go about handling
the
>>Throttle Position Sensor.
>>
>>ie:  While the engine is in a steady state condition the combination
of
>>MAP and Barometric Pressure sensors along with RPM determine the
initial
>>injector pulse width.  The O2 sensor closes the loop.  Now if the
>>throttle is opened suddenly I know I need to increase the pulse width.
>>
>>I can:
>>
>>1)  just use a timer to increase the mixture to 10:1 for a
preprogrammed
>>time.  This simulates the accelerator pump on a carburated engine.
>>
>>2)  Increase the mixture to 10:1 until the ratio between MAP and
>>Barometer reach some set point.
>>
>>3) Do both.
>>
>>What I don't want happening is a too rich mixture once the throttle is
>>wide open and the engine is loaded at some RPM that no longer
increases.
>>
>>Would I be best to use the rate of change of the RPM as an indicator
to
>>back off on the Pulse Width?
>>
>>What do the commercial injection systems do?
>>
>>Comments?
>>
>>Thanks,
>>
>>John
>>
>
>