Thots cont'd

[John S Gwynne]

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Date: Thu,  5 May 94 17:42:55 CDT
From: Steve=Ravet%Prj=Eng%PCPD=Hou at bangate.compaq.com
Subject: re: Thots cont'd
To: twisto.eng.hou.compaq.com!wotan!coulomb.eng.ohio-state.edu!Diy_Efi-Owner
Cc: 

Mpalmer at ndigital.com (Mike Palmer) Wrote:

| >One thing I have noticed that has been missed so far is battery 
| voltage.  
| >You need to measure this to correct the pulse width sent to the 
| injector.  
| >Perhaps there are some new injector driver circuits out there 
| that do this?
| >
| >I have been using the MC 3334 form Motorola.  
| 
| Yep. It will be necessary also to scale battery volts into the
| fuel delivery. One way to establish a crude correction table 
| would be 
| to have an injector fire into a measuring crucible for a specified
| number of pulses at a constant fuel pressure and pulse-width. For
| various battery volts from 6.0 to 17.0, measure the quantity
| delivered and then apply a scale factor to the applied pulse width
| based on the battery voltage to achieve constant deliveries.

What voltage does an injector need to open?  If it is an electro-magnetic
device like a solenoid then voltage isn't really important, as long as
there is plenty of current.  If the voltage level is important, then it
would be simpler to use a regulator to keep the voltage constant at, say,
10 volts.  If battery voltage drops below that, the car isn't going to run
well anyway, regardless of what the injectors are doing.