I too have started learning the Arduino, so far l have been able to write a code that turns a LED on and off lm a genius am l not?
But seriously, l have been thinking about this stuff for a while now. Lots of problems if you want to make it right.
Per instance, there may come a time when you want to run rich. Like in heating up the gasifier after a long idle. But then again, since o2 se.sor only takes combustable gases to acount, maybe it wuld self richen when weak gas comes in? God knows…
I dont think there is any other good way but to phisicaly measure your gas somehow, with a O2 sensor after combustion or with some exotic sensors before the engine. In the last case, you can probably add a few zeros to the cost…
Problem is that a wideband O2 sensor has a linear voltage output/fuel ratio graph, while the narrow band has it all messed up, bell shape.
So, the controller can also not be linear if we use a cheaper narrow band sensor.
But the good news is woodgas realy doesent give a damn for exact a/f ratio. If its in the ballpark its gonna run ok. Its when different conditions throw it off ballance severely that problems occur… but we got the automixer to fix things back to the ballpark area. That, lm sure is much easyer to achive, and also with a narrowband.
I have spent hours looking on the voltage display from my narrowband sensors (l never owned a wideband) while driving, l got an idea how this works, but l cant remember exact voltages… l never set the a/f ratio based on o2 sensor, rather l set it by feel and monitor whats happening with the sensor…
basicly, l ran the seting on the rich side, to compensate for sudden lean pockets of gas when taking off etc. But idealy, woodgas likes it lean, so l traded some power and efficiancy for comfort. This l wuld like to fix with the automixer.
Im thinking, culd it be possible to make this controller to work in steps? Like l sayd, woodgas isnt a picky thing… Basicly, instead of having one air valve governed by the Arduino, culd it be possible to just have a couple of small valves to just throw in a bit more or less air, to fine tune the ratio but the main seting wuld still remain manual. Maybee just two wuld be enaugh, one for richening and one for leaning.
Main advantige here might be that l can not imagine a cold start with just a o2 sensor automixer. The sensor is cold, gas isnt constant… so a mean of manual override sistem is a must and since we alredy have it installed, why not just build on it with the arduino?