Lambda?

[Ev0cRaZy]

I just installed a Zeitronix wideband and was wondering what Lambda means? o2 or what?

[FastEvoFL]

Lambda just means stoich for the fuel mixture.

gasoline stoich AFR = 14.7
Lambda = 1.0

AFR = 11.76
Lambda = 0.8

Lambda is basically just the multiplier to the AFR. From what I've read is we all use AFR to measure mixture but people in other countries like to use lambda. Some rather use lambda while others like to use AFRs. Hopefully you can actually change what the your unit displays(either lambda or AFR.)

check this thread

Tuning with AFR or Lambda?

[donour]

For fuel metering, lambda is defined as AFR/stoichiometric. So if you are, for example, reading an 11:1 afr on gasoline then

lambda = 11 / 14.7 =7.55

Notice that lambda has no units. Many 02 sensors, such as the bosch unit used in a lot of widebands, actually measure lambda, not AFR. To get back to AFR, you multiply by the stoichiometric ratio.

d

[donour]

Originally Posted by FastEvoFL

L From what I've read is we all use AFR to measure mixture but people in other countries like to use lambda. Some rather use lambda while others like to use AFRs. Hopefully you can actually change what the your unit displays(either lambda or AFR.)

Well, not so much. Most folks would probably agree that lambda is more natural way of thinking about air/fuel ratios -- especially when tuning for a variety of fuels. It's like radians and degrees. Centuries of mathematics has told us that radians provide a far more elegant description of angle, but everybody (myself included) uses degrees for back of the envelope calcuations.

d

[FastEvoFL]

Good point.

Just some numbers make more sense.

PSI makes way more sense then atmospheres or bar but yet people still refer to them. Heck at work we use inches in water gauge which makes no sense!

[donour]

Originally Posted by FastEvoFL

Good point.

Just some numbers make more sense.

PSI makes way more sense then atmospheres or bar but yet people still refer to them. Heck at work we use inches in water gauge which makes no sense!

You're just describing the SI units phenomenon. They seem strange if you don't use them much and have no feel for them in your gut. If you stand back and look at it, bar actually makes a lot more sense than pounds per square inch. The numbers would come out a lot nicer. Why not use Newtons / square meters , but you're right. Because we deal with pounds and inches every day, PSI makes more sense to a lot of people.

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