[Diy_efi] ignition timing variation

[huw scourfield]

Not if you want accurate transient timing, any averaging will kill this.
Best answer is to increse the No of teeth on the wheel. BTW I have long
since believed that at high rates of accelleration a given engine will
"tolerate"- or even require, much more advance than it would in steady
state. This might or might not have a bearing on your question, but
certainly the grater the speed of updates, the better.
    Huw
----- Original Message -----
From: "Stewart Prince" <sprince at csun.edu>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, July 30, 2002 8:57 PM
Subject: [Diy_efi] ignition timing variation


> Does anyone have any information on "acceptable" variation of ignition
> timing?  We're getting about +/- 2 degrees of jitter on our home-built
> EFI system (Formula SAE).  By my calcs, 100 microseconds of error
> corresponds to 1.8 degrees of rotation at 3000 rpm, and 7.2 at 12,000
> rpm (assume constant angular velocity). I believe the students are using
> the time between the last two teeth on an 8-tooth wheel (crank mounted)
> to calculate engine speed.  Is it possible that some sort of averaging
> scheme should be used to account for the speed variation due to
combustion?
>
> --
> STEWART PRINCE
>
> PROFESSOR, MECHANICAL ENGINEERING
>
> CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
>
>
>
>
>
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> Diy_efi mailing list
> Diy_efi at diy-efi.org
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