[Diy_efi] Timing Calculations

[Astrona]

Injection is time-based, but shooting-angle is also important.
Ignition is angle-based, but dwell-period is also important.

If you have big enough injectors to avoid 100% duty cycle in every case,
you can just open the injector at desired angle and set the timer (no
degrees!) to shut it.

Should close the issue or redefine it.



----- Original Message ----- 
From: "Mark Higgins" <nospam at higginstribe.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, June 16, 2005 10:26 PM
Subject: Re: [Diy_efi] Timing Calculations


> Has anyone actually made their own EFI on this list, cuz this is kinda
> annoying.
>
> You are basing your idea of injector timing in sequential mode, that it
> is a single event, when it is more accurately defined as two events.
> One event opens the injector and one event closes the injector.  Both
> the open and close points of the injector need to be calculated, unlike
> in batch mode where you can just modulate the PWM and injection is not
> an event at all,
>
> The ignition event is simple, since it's an instantaneous event that
> only cares about it's own position.  The injector ON event doesn't care
> about it's position, it only cares about trying to accurately determine
> when to turn on so that the injector will be open for a set amount of
> time before it reaches the injector off position.  The injector off
> position cares about two things, it's position and whether the injector
> has been on for the specified amount of time.
>
> Because of the acceleration I have to deal with the on and off event
> coming closer together time wise, which will ultimately effect the
> amount of fuel.  So, the acceleration/deceleration problem will
> ultimately effect the amount of fuel , starving it on high acceleration,
> which, yes, I'm more worried about that than 1 or 2 degrees of ignition
> timing.  But, if I fix one, it will work towards fixing the other.  Yes,
> I know about the importance of ignition timing, can we get over that now?
>
> Mark Higgins
>
> Adam Wade wrote:
>
> >--- Mark Higgins <nospam at higginstribe.com> wrote:
> >
> >
> >
> >>Of course for batch fire it doesn't mean much since
> >>there's no individual injector timing.
> >>
> >>
> >
> >That was the whole point.  Batch fire vehicles run
> >just fine, and make excellent power; in fact, I doubt
> >you could tell me whether a vehicle was batch or
> >sequential fire, even looking at dyno data with
> >four-gas analysis.
> >
> >Injector timing makes very little difference once you
> >get very far above idle speed.
> >
> >
> >| 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr 550 (Daphne) |
> >| "It was like an emergency ward after a great catastrophe; it  |
> >|   didn't matter what race or class the victims belonged to.   |
> >|  They were all given the same miracle drug, which was coffee. |
> >|   The catastrophe in this case, of course, was that the sun   |
> >|     had come up again."                    -Kurt Vonnegut     |
> >| M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |
> >
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> >
> >
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