Add-on board 1 for DFH

Jared's unmaintained and never-used TA based "Defacto FreeEMS Hardware" design.
User avatar
Fred
Moderator
Posts: 15409
Joined: Tue Jan 15, 2008 2:31 pm
Location: Home sweet home!
Contact:

Re: Add-on board 1 for freeEMS_1.0 rev A

Post by Fred »

If you usually use 4 you will use 8. Your board should specifically not support staged injection at all. It's only used for extreme applications, and even then only a fraction of the time. Using a single extra is a filthy hack that I won't be writing code to support as it DOES lead to uneven fuel distribution and lean cylinders. This is supposed to be at least somewhat sophisticated ;-)

EDIT : This is the add on board thread :-) Yes, support 6, but beware that they will not be driven the same as the main 6 due to polarity configuration of those 6 channels.

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!
User avatar
jharvey
1N4001 - Signed up
Posts: 1607
Joined: Tue Jun 10, 2008 5:17 pm

Re: Add-on board 1 for freeEMS_1.0 rev A

Post by jharvey »

Great, that's what I wanted to hear, also glad to hear about the 6 not 1 thing. I'm thinking of using the existing board layout as a starting point for the first add-on board, but moving the IO around when it connects to the TA card. Before I start I'd like to get a better grasp of what can fit on this first add-on. Just poking around trying to connect hip bones to leg bones and such.
WTDeuce
QFP80 - Contributor
Posts: 40
Joined: Thu Sep 04, 2008 1:54 pm

Re: Add-on board 1 for freeEMS_1.0 rev A

Post by WTDeuce »

jharvey wrote:I'm wondering about the staged injectors. Are those intended to have one extra injector per cyl, or should there be one staged injector that covers them all.

My understanding of staged injection is that when at an idle, you need fine control over the fuel. However with an injector that can give you WOT fuel, you often loose that control fine control at idle. If you use one smaller injector for the fine control, and a second injector to bump up the fuel when running harder, you can keep the fine and power control.

What I'm not understanding is if there is one larger upstream injector that fuels all the cyls, or if it's a separate injector per cyl. Perhaps we plan to support both? I'm mostly curious for electrical reasons. Should we have one injector driver or 6 injector drivers?
Remember that true sequential injection eliminates many of those idle with big injector problems...
Post Reply