Auto-LPG Conversion Thread

[dencio1976]

Dencio! I think I figured it out. You're right, the plate is inserted below the carb's throttle plate and the manifold. The plate seems to introduce outside air into the A/F mixture after the carb through a port that allows atmospheric air to be sucked by the vacuum in the manifold. That in effect leans out the mixture from your fuel jet settings!

Now, the stepper motor operates an air valve that controls the amount of "manifold leak" introduced to the A/F mixture from the carb. It is activated by electric pulses from the O2 sensor (I think +/-8V) so that the opening of the valve to and from atmosphere to depressed vacuum is controlled in maybe 16 increments.

Probably the carb mixture is initially set rich, and the O2 sensor then begins to lean out the mixture in increments by introducing pure air into the mix below the throttle plate. The stepper valve essentially introduces an "leaning out" of the mix until stoich is reached, then backs off when throttle is further depressed or is shut down.

The question to ask is: can I use this to lean out my autogas mix if I could introduce the gas mix in rich condition and have the stepper lean out the mix until I achieved stoich? Same principle right? steve

yup i had this in mind. only im curious how the O2 sensors really work. got any finds on what O2 sensors do in your exhaust manifold?

Except perhaps, for the fact that petrol stoich is different from gas stoich! Therefore, is it possible to re-map the ECU to work on a different stoich value? If it could, this device would be a useful (and readily available) solution to closing the feedback loop, increasing economy, output power, and cleaning up the tailpipe of autogas cars!

What do you think?

steve

an alternative: with the stock ecu at gasoline stoich value, (1 less than the value for LPG), it would be rich a/f. mods would be necessary. a technology that one(like me) cannot easily reach(for DIY). it'd be something if you could reprog the ECU.

i just came up with the fuel variation idea for LPG. since your LPG kit comes with solenoids, opening can be varied with however a constant air opening. (a much simpler setup i think). with the O2 sensor at the exhaust manifold, a gauge of somesort (a simpler one like a/f gauge for example)would act as the trigger input for the solenoid variation opening. voila.. instant closed loop! (if only it was that simple)

oh and i would also consider water temp variation as well. it's impt for the temp stabilization of the lpg. too hot meant not good for intake. cool meant something in equivalent for cold air intake. (just a little more and i think we've come up with a great idea)