Re: Wasted spritz (was Wait one friggin' minute!)

[Ben Barkow <dr.ben@xxxxxxxxx>]

On 2006 Jun  21 , at 4:47 AM, oilheads-digest wrote:
> Most modern engines that use a coil per cylinder "waste a spark" on the
> exhaust stroke as a method to keep the plugs clean. Since the pressure 
> in
> the cylinder is low and the atmosphere is reducing, there is no 
> possible
> erosion or oxidation of the metallic parts. This is an old trick that 
> has
> again become popular as a way to improve emissions.
>
> No, the fuel injector is not firing during the exhaust stroke. With a
> carburetor, some fuel would start to flow during overlap at the TDC 
> when
> both valves are open, but with port injection, this is not necessary.
>

I think this year's ECU no longer wastes a spritz, but not earlier ones.

Spraying gas during the exhaust phase seems a really dim way to run an 
engine (comparable to the old "fountain" injection although that may 
make sense for multiple cylinder engines) and maybe that is why the 
respected Mr. Moss would be surprised. Barely pennies to have a second 
power transistor to drive the two injectors separately from the same 
fueling program.

Actually, I've suggested that the Techlusion people introduce this 
change because it can be easily handled in their 1031 or 259 boxes, I 
think. If they did it, it might save as much fuel as their excellent 
enrichment add-on sometimes adds.

Ben
Toronto

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