[Diy_efi] Peak cylinder pressure timing

[steve ravet]

Phil Lamovie wrote:
> Lets say we log lots of incremental values into a table;
> say pressure vs degrees crank.
> 
> The issue then becomes one of how to use the data acquired.

There's a thesis that's been posted before from a graduate student using
ion sensing to determine the peak pressure point, one of his
applications was to use that as feedback for ignition timing so that the
peak pressure was always at the "best" crank angle.  That wouldn't
require any fancy math, and would eliminate the "spark tables" current
used.

> If you can do fast samples with an FFT function the area under
> the curve (torque) becomes apparent.

Instant torque is cylinder pressure times piston area times the
"horizontal" component of the crank arm, right?  Average torque is the
integral of that, also no fancy math required.  I'm not sure what use
average torque would be other than display it for the user -- maybe
traction control?

--steve

-- 
Steve Ravet
steve.ravet at arm.com
ARM,Inc.
www.arm.com

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