[Diy_efi] 555 timer for injector driver

[Bobby Yates Emory]

Mark,

I get the drift that most engines are not precisely timing the moment that 
an injector is open. What they are trying to get right is the duty cycle - 
is it open 40% of the time or 45%?

If the relay takes an equal length of time to open or close the circuit, its 
delay would be irrelevant. If it is faster for one or the other, that will 
bias the timing, but should be something one can work around - but remember 
the timing is reversed, because you are using the relay to ground the 
injector.

Should allow Jeff to perform his experiment.

Bobby

On 7/6/05, mark krawczuk <krawczuk at dodo.com.au> wrote:
> 
> 
> 
> 
> HI , this is as far as i know....
> 
> you have power ( positive 12 volts) going in one side of injector, then u
> switch the earth side to make the injector open/close.
> u dont need a relay to drive the injector, use the 555 timer to
> switch/pulse a power transistor to switch the injector, cause the relay ,
> if used to switch a injector open for fuel use will take tooo long.
> 
> i am not sure if the 555 time can switch enough current by itself ????
> 
> even though, using a relay to operate injector should work,.
> 
> mark k
> 
> 
> ----- Original Message -----
> From: "jeff matthews" <maple69vt at hotmail.com>
> To: <diy_efi at diy-efi.org>
> Sent: Thursday, July 07, 2005 11:09 AM
> Subject: [Diy_efi] 555 timer for injector driver
> 
> 
> > Hi-
> > To keep my ??? simple, I built a 555 timer to work on a little
> > experiment, I have it energizing the solenoid on a 12v relay, why won't
> > it open and close my injector? (it's just a basic saturated 550cc). Is
> > there some secret to on making an injector operate?
> >
> > Like I stated, this is for an experiment, just thought I could handle
> > making an injector fire on the bench...
> >
> > Best regards,
> > JEFF
> >
> >
> > _______________________________________________
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> >
> >
> >
> 
> 
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-- 
Toward freedom,

Bobby Yates Emory
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