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Debate y preguntas relacionadas con el curso Fundamentos de la puesta a punto de la inyección electrónica de combustible (EFI).
= Hilos resueltos
Is the AFR the same on all pump gas, like 87 91 93??
Yes, their Stoichiometric AFR is the same (around 14.7 or Lambda 1.0) because they are all standard pump gas. However, under WOT (Wide Open Throttle), 87 needs a richer target to prevent knocking compared to 93
Keep in mind the ethanol content, at least in EU there is a 5% ethanol in pump unleaded. So stoich is around 14.5
This is all a great lesson in why lambda is preferred over AFR when discussing mixture.
Lambda is is based on the actual oxygen content measured by your O2/lambda/wideband sensor (whatever you prefer to call it). AFR is derived from that based on an assumed stoichiometric ratio of the fuel you are using. Fact is that, unless you are measuring your fuel every time you fill up, you don't know the stoichiometric ratio of your fuel - It's just an estimate. Lambda is always lambda regardless of what fuel you are using, unless you get into highly oxygenated exotic fuels like nitromethane.
That being said, the stoich ratio of all pump gasolines are more or less very similar, regardless of the grade. Ethanol content has much more of an effect.
This is why your consumption increases on your stock street car when your local gas switches to summer blends or your government mandates a switch from E10 to E15 to cover for the wartime increases in fuel costs - these fuels have a lower stoich ratio, the oxygen sensor sees that in what it measures, and the ecu trims the fuel up to cover this change.
Do yourself a favor, break up with AFR and start thinking in lambda. I promise it will make life easier in the long run.
