Combustion Pressure Sensor - revisited

[M. Jones]

Just read on AVweb, an aviation oriented on-line magazine (www.avweb.com -- 
subscription required, but free) where GAMI (General Aviation Modifications, 
Inc.) has developed a system which allows them to monitor instantaneous 
combustion chamber pressure.  They drill a small hole in a spark plug and fit a 
"proprietary sensor" to accomplish this.  Beyond that description, they 
apparently ain't tellin.  The graphs presented in the article are pretty 
interesting.

All of this is extremely interesting to us aviation types, 'cause aviation 
recips are operated with FIXED timing, optimized for ONE condition -- full 
throttle, a set RPM, and rich mixture.

Anyway, for the article, go to www.avweb.com, chooses Columns and select 'That 
Misunderstood Mixture'  At some point, you'll be asked to subscribe (free). 
 The article (the last third or so, anyway) actually is a pretty interesting 
discussion of mixture and timing consequences, and includes a couple of 
combustion event graphs.

Mike Jones

Tom Butler wrote:

This thought has occurred to me as well.  A possible problems with this
approach might be drive line shocks propagating back to the crank shaft.
Perhaps the transients occur on a different time scale?  I'm sure an
algorithm could be cooked up to extract the required information, provided
the "noise" can be eliminated.
TomB

> -----Original Message-----
> From:	Tom Sharpe [SMTP:twsharpe at mtco.com]
> Sent:	Wednesday, June 16, 1999 12:45 AM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Re: Combustion Pressure Sensor - revisited
>
> Can measuring crankshaft acceleration per degree dewtermine the sweet spot
> and how close you are to it???  TomS
>
>