injector drivers Hey Carl S

[Bruce Plecan]

-----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 11:37 PM
Subject: Re: injector drivers

I, don't know what to tell ya about boats.  The load is so great all the
time.  Seems
to me a TB with vacuum secondaries would be the only way to go.  I did some
carb
work, many years ago and about went crazy trying to get the perfect
metering....
Maybe Carl could shed more light on this.
For boats might get by with MAP to RPM AE type table, best,
Bruce


>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
>>>
>>
>>
>