Another injector question

[Steve Ruse]

James, thanks a lot for your help!

>I went with MAF because I was under the impression a MAF system had a lot
more
>'play' in it than a speed/density system. That is, a MAF system is more
>adaptable to changes in your EFI hardware than a MAP system, the software
>tables of which are generated for a certain throttle size, engine
displacement,
>etc. only.
>
>Of course, a MAP system might be easier to implement and will probably give
you
>more reliable airflow data due, to the relatively long response time
inherent
>to MAFs.
>
>Our smallish (42mm dia.) low-flow (3-250 kg/hr) MAF sensors were donated to
us
>by Siemens Automobiltechnik in Germany. They like to sponsor teams like
ours
>and have their stickers gratuitously plastered all over our vehicles.


Heh heh, I need to make some calls......

>> Right now I am leaning towards (mostly) software control, via either a
>> 68 series Motorola processor or through a PC/parallel port.
>
>I'm using a Motorola 68HC812A4 microcontroller on a board with 128 kb of
>additional memory (which I need for the lookup tables). It's got over 40
>digital I/O ports and 8 A/D channels, which are enough to handle all of the
>sensors. There are inexpensive C compliers and freeware assemblers for this
>processor, so programming it is relatively easy. I'm driving the injector
with
>a National Semiconductor LM1949 injector driver.


Where can I find the C compilers etc. for the 812? I'm not our "software
guy", and all of my experience is with the 6811.

>Sensor-wise, I'm using a shaft-mounted optical encoder to measure rpm
(there
>are cheaper ways to do this, but we had an encoder sitting around) and some
>hall-effect sensors to determine crankshaft angle. Engine temp. is being
>measured with a thermocouple, and I've also got a throttle-position sensor
to
>measure throttle angle and rate of change.


That is what I am thinking too. Why not use an optical encoder to measure
the crank angle? We are going  to do some testing with an optical wheel on
an electric motor before too long, just to see what we can do with it. What
optical encoder are you using? Also, what are you using the TPS for?
Enrichment at higher throttle positions? I was thinking of using a "3D"
table with enrichment as a function of MAP for that.

Thanks!
Steve Ruse

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org