DIY_EFI Digest V4 #569

[Tom Parker]

DIY_EFI Digest <DIY_EFI-Digest-Owner at efi332.eng.ohio-state.edu> wrote:

sorry for mangling the quotes...

>> No, it does.  You have to have a very good accuracy (I think the minimum
>> is 6 "steps" per revolution) because otherwise the system will get
>> confused when the engine changes speed quickly.

>I did some calculations to check into what kind of errors you'd get on your
>speed under constant acceleration if you used a single pulse per revolution

>Speed [rpm]=> V1 =  60.0 / (T1 - T0)

<good stuff snipped>

>More pulses per revolution will increase accuracy but do all applications
>need it?  I think you could do it with a pulse every second revolution and
>have it run better then a carburetor.

>Will McGonegal

If you hook up to the coil, using a distributor to drive the ignition, then
you get 2 pulses per revolution on 4 cyclinders, 3 from 6 cycl and 4 from 8

I think you could easily do with only the distributor as a crank position
input, SO LONG AS YOU DO NOT CONTROL THE IGNITION SYSTEM from the computer. If
you want to do ignition timing, then those errors are going to hit you (well,
I have a qualitative feeling that they will matter).

--
Tom Parker - parkert at ihug.co.nz
           - http://www.geocities.com/MotorCity/Track/8381/