[Diy_efi] Re: new EFI controller

[Marcell Gal]

Hi Bill, 

> Define inefficient. It is all a trade off to do with steering the flyback current.

Did you look at the circuit carefully?
( http://caffrey.dk/megasquirt/ schematic, last page, T3 )
To connect (the zener-emulator) to GND instead of 12V is
simply a mistake. It does not make the injector switch off faster.
The additional 12 V just heats the transistor more
instead of putting back the current to the supply for
some useful purpose. There's no tradeoff there. Bad in every
ways (heat,cooling,space,component selection, energy)
without any  positive effects
(the injector sees the same voltage, since you have to use
a higher voltage zener that way). It even worsens predictibility,
since switchoff will depend on supply voltage.
That's what I mean by inefficient. 

If you think of dissipating the injector current faster
(zener instead of a schottky or diode), that's really
a tradoff, that can be justified, (the MS discussion is about
this topic, right?) but I'm NOT talking about that
one this time. 

Marcell 

-- 
+36 70 2 654 789 

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