Old 486 Board for ECU??

[Axel Rietschin]

----- Original Message -----
From: "Axel Rietschin" <Axel_Rietschin at compuserve.com>
To: <diy_efi at diy-efi.org>
Sent: Monday, May 01, 2000 9:44 PM
Subject: Re: Old 486 Board for ECU??


>
> ----- Original Message -----
> From: "Mike from West Australia" <erazmus at wantree.com.au>
> To: <diy_efi at diy-efi.org>
> Sent: Tuesday, May 02, 2000 01:57
> Subject: Re: Old 486 Board for ECU??
>
>
> >
> > At 05:08 PM 1/5/2000 +0200, "Axel Rietschin"
> > <Axel_Rietschin at compuserve.com> wrote:
> >
> > Engine at 9000 rpm = 150 per second = dist 75 per second
> > For a CAS with 360 deg pulses/rev thats 75*360 = 27KHz
>
> This gives you a base resolution of 37 microseconds. *Far* too coarse to
run
> any engine at low speed. Forget driveability and low emissions :)

To emphasise the 'far too coarse' part, think that a system based on a crank
interrupt every two degree as 'master clock', as you suggest, will result in
a resolution as low as 333us per tick at 1000 rpm. This will probably result
in very poor idle, in addition to the poor emission and driveability issues
I've already mentionned.

Also, two degrees resolution for spark timing is also too coarse to allow
you to extract every bit of torque from a given engine.

:)

--Axel




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