At 07:20 AM 8/18/00 -0700, you wrote:
>[...]
> |
> --operating point (somewhere near stoichiometric efficiency)
>(I may have the voltage range wrong, it has been a while since I've used
>these things)
(The ones I have seen are 0-1v, but the principle is the same.)
>I know they've done some work to make this look more like an S-curve, so
>that closed loop analysis can be more useful, but I remember reading that it
>didn't help too much, and the new sensors were really expensive (like
>$500?). I couldn't find any data on it though.
Yep, there are wide band sensors available for things like dyno tuning,
and also there are some aftermarket EFI systems that use them to dial in an
EXACT A/F ratio. Its pretty cool, you can just tell the computer "give me
a 12:1 ratio", and it does. Closed loop at WOT; great stuff! :-) That
also can eliminate the need for dyno tuning. You can tell the computer to
shoot for a particular A/F ratio, then drive the car, and use the data
generated by the computer (as it makes adjustments to keep that ratio) to
populate the open loop lookup tables. It won't be 100% dialed in, but
it'll certainly be more than driveable. Some EFI systems require an hour
or two of dyno tuning before you can even drive the vehicle.
You're right, the wide band sensors are very expensive. ($500-$1000,
and some are even more I'm sure) However, one of the Honda V-TEC engines
(1995 I think?) was a "lean burn" engine that they used one of these
sensors in. Since its a mass produced item, you can supposedly pick them
up for $130 or so. I've seen a picture of that particular sensor, and it
looks like the same one that's used in the SpeedPro EFI system.
-Jon-
.--- Jon Steiger ---- jon@dakota-truck.net or stei0302@cs.fredonia.edu ---.
| Affiliations: AOPA, DoD, EAA, NMA, NRA, SPA, USUA; Rec & UL Pilot - SEL |
| '92 Ram 150 4x4 V8, '96 Dakota V8, '96 Intruder 1400, '96 FireFly 447 |
`------------------------------ http://www.cs.fredonia.edu/~stei0302/ ----'
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