Once in a while I get annoyed when I don't know something when everyone else does, or so it seems. Anyone wondering what the hell people are talking about when referring to a "lambda"? It sounds like an animal if you read it too fast.
I don't see why calling it an O2 sensor is so much harder?! If it's an oxygen sensor, why not call it that? Sounds like one of those words people use to make them sound like they know more about something (especially with unnecessary abbreviations) or try to confuse other people who aren't as seemingly "savvy" as others.
Maybe so. Still. "O2 or Oxygen" following the word "sensor" is if not easier to type as "lambda" and makes more sense. But here's an explanation behind the whole word. Especially for those of you who know what it is but don't know why it's even said that way. (Kind of like in hockey when people say the Habs).
A lambda sensor is the same thing as an oxygen sensor. In the USA, they are commonly called oxygen sensors, while most of the world calls them lambda sensors.
SO WHY DO THEY CALL THEM LAMBDA SENSORS?
We were hoping you'd ask. As near as we can figure it is a 2 fold answer. The Greek letter lambda equals 1. The purpose of the lambda sensor is to help maintain the fuel ratio at 1 part fuel to 14.7 parts air. Therefore the lambda sensor reports if the fuel is at "1" or "lambda".
As a second explanation it was offered us that when viewed on a scope, the wave pattern produced by the original oxygen sensors resembled the Greek letter lambda. Therefore they were called a "lambda" sensor. (From what we have seen, lots of oscilloscope wave patterns resemble the Greek letter lambda, so we're suspicious of this 2nd explanation).
You have our permission to propagate whichever of these two explanations you like, just don’t quote us on either.
Sources:
Sparkplugs.com - Spark Plug 411
Lambda sensors / exhaust oxygen sensors
Hope this helps at least one other person out there.
And sorry for those of you who read this and are pissed off for wasting your time because you already knew it.