water4gas O2 sensor

[raburgeson]

EFIE seems a bit over engineered to me. I need to add 0 to 550 millivolts to the oxygen signal. What's wrong with this thinking. A voltage divider, a Darlington, an inverter, and a summing amplifier. In that order wouldn't I be able to add a pot adjusted 0 to 550 millivolts? EFIE boards cost $60 and the parts list (build it yourself costs $72), my way $20. I goof now and then on my way logic so, I ask do you see anything wrong with it.

[raburgeson]

Found a non-inverting summing amp that will hold 1% tolerance with a DC signal, I won't need an inverter.

Guys if you don't isolate the ground on the ramping signal it's possible the device might not work at all, it depends on the computer design. Input impedance and a few other factors go into it. It's all CMOS technology sure but, there are many designs out there. Instead of trying to hit a perfect regulated input it may be far better to just adjust an output that definitely leans the mixture. If it pings or there is a power loss then you've added to much signal. The summing amp isolates both grounds for you.

The amperage from my voltage divider is to low, that's why I need to add a Darlington. I always go for the clean look of a couple of chips over soldiering up a whole bunch of crap. They put a summing amp capability in a chip I'm sure going to take advantage of it. What I have been combing the books for now is a chip that has the summing amp and the Darlington on the same chip. I'd like a chance to make it cleaner yet and make it single socket clean.

Over 45 mph my mileage drops quickly, my beast of burden is under powered. If I adjust it for city driving I'm set, I'm going to need that little bit richer mixture for highway anyway. 35 to 45 were I get the best mileage I never get to use. 35 in town is tops and the traffic on the highway would cream your back bumper if you tried to go 45. For the couple of minutes I could realize a better mixture it's not worth going through all that crap to add a special signal for that extra lean condition at that particular speed that may or may not work. That it's definitely leaner at my best mileage speed is enough.