In cylinder pressure measurement

[Todd....!!]

Charles, it sounds as though you need to get some sorta input as to how
much torque is being produced by the engine.. One way could be to put
two sensors somewhere along the drive shaft or an axle shaft or
something that you could calulate the 'twist' of the shaft using the two
sensors timing differencs due to the varying load on the shaft that they
are located on...

i.e. if you know that a 2 inch solid shaft twists .1 inch with 100 ft
lbs of torque applied to it, then using the sensors' timing difference
of whatever the difference of time at a given rpm that the sensors'
measure a .1 difference in shaft twist would be calculating that the
engien is producing 100 ft lb.s of torque at that time....

Don't know if I explained that too well, hope ya get the point?

Good luck, sounds like your DEFINITELY on to something here!

Just don't lose sight of the issue that you're dealing with and what
you're trying to solve....

Sounds like you will, at least in part, produce a device that's at least
one step better than a knock sensor?...

LATER!

Todd....!!
http://www.c-com.net/~atc347/toddlnk.htm


Charles Brooks wrote:
> 
> Hhmm, OK. So I use a hall effect sensor on a toothed wheel and calculate acceration from the change in PRI as seen at the HE sensor. If I have a motor running at 5000RPM/60seconds=83.33RPS  and a DAQ with a 10KS/s sample rate I get 120 samples per revolution. Now, how would I compensate for engine loading? Acceleration would be higher in 1st gear than in 4th, it would also be higher going downhill than it would be going up. There's also internal friction to consider. Could probaby get around the
> 
> Charles Brooks
> 
> ---------- Original Message ----------------------------------
> From: Tom Sharpe <twsharpe at mtco.com>
> Reply-To: diy_efi at efi332.eng.ohio-state.edu
> Date: Wed, 12 May 1999 23:33:49 -0500
> 
> >Let's see... the piston measures combustion pressure... hooked to a rod...
> hooked to a crankshaft....If we could measure crankshaft acceleration 60 times a
> revolution, we could come up with some relative numbers... we need a toothed
> wheel and sensor and ????... Sharpe