Lee,
I've thought about doing something similar but I was planning to just gut
the metering control unit and replace it with a servo, MAP sensor, and
computer (and O2 sensor later). If you're going to modify the thing anyway
why bother keeping the whole spring & datum track arrangement?
Another approach- hook a servo up to the calibration screws and just
'calibrate' the metering unit in real time. Do you have the Lucas 'red
book' which has the PI calibration documentation?
Cheers,
-Erik (74 TR-6 PI)
At 02:37 PM 3/27/2001 -0700, Janssen, Lee K wrote:
>As usual I have not correctly stated my problem. The following Q & A should
>clarify my problem.
>
> > What are you trying to do with the addition vacuum?
>
>Well... The PI system sets the mixture based on the manifold vacuum. At best
>the system is only approximate since it is an open loop controller. Since I
>have exhaust gas oxygen sensors I was going to build a circuit that adjusts
>the vacuum in the metering unit so that the fuel to air mixture is correct.
>The circuit consists of a solenoid vacuum valve that is driven at a fixed
>frequency where the duty cycle is adjusted to provide the correct vacuum to
>the metering unit. Mechanically the metering system will be set rich and
>electronically I will lean it out to the correct mixture. Another option is
>to provide pressure to the back side of the vacuum diaphragm, however, this
>may interfere with the normal operation of the metering unit and will only
>be used as a last resort.
>
>Yes this does sound like a lot of work for a little bit of gain, however,
>there are much bigger plans IF I demonstrate that this will work ;)
>
>Thanks to all who responded (and more thanks to those who don't flame me)
>Lee Janssen
--
Erik Quackenbush, V.P. Operations, Midwest Filter Corporation
1-847-680-0566 fax: 1-847-680-0832 http://www.midwestfilter.com
///
/// triumphs@autox.team.net mailing list
///
|