PWM injector driver

[Ludis Langens]

Brian Michalk wrote:
> 
> The Bosch books I have states that the injectors fire once per
> crank revolution, therefore twice per power stroke.
> 
> So my question is: do I really need a crank signal to synchronize
> TDC with my injector firing?

How often are you firing the injector(s) in relation to the engine's
induction events?  If you aren't synced to the crank, one engine cycle
may get n injections, the next cycle n+1 (or n-1) injections.  So,
what's the relation between n and n+1?  Can your application tolerate
this variation?

In a crank synced batch fired system, all the injectors fire at once. 
This means that some of them are not injecting at an optimal time.  The
OEMs have had good luck with this - so it mustn't be a problem.  The key
seems to be that all cylinders get the same amount of fuel.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/

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