The air-fuel ratio, or lambda number (λ)
determines the mass ratio of air and fuel in the combustion chamber
, as it relates to the stoichiometric air-fuel ratio. When λ=1, ideally balanced combustion conditions result in neither oxygen starvation nor excess.
What is lambda AFR?
Air–fuel equivalence ratio, λ (lambda), is the
ratio of actual AFR to stoichiometry for a given mixture
. λ = 1.0 is at stoichiometry, rich mixtures λ < 1.0, and lean mixtures λ > 1.0.
How do you read a lambda air/fuel ratio?
Another way to look at air/fuel mixture is lambda value. It is represented by the Greek symbol “λ.”
Lambda equals AFR divided by stoich
. When measuring air/fuel mixture using lambda, stoich will always equal one (1) for any fuel.
What is lambda in automotive?
The Greek letter lambda stands for the
so-called “air ratio”
. Only when lambda = 1 can the catalyser optimally fulfill its task of cleaning the exhaust gas. The lambda control forms a closed control loop in which the lambda sensor, working as a measuring sensor in the exhaust flow, measures its composition.
What should lambda readings be?
Checking your lambda sensor with a multimeter
When you start your engine, a reading
between 0.4–0.6V
should appear. Once the engine is up to temperature, the reading should alternate between 0.1–0.9V. The ideal engine speed for the best measurements should be at 2,500rpm.
Is it better to run lean or rich?
TLDR –
running just a little lean
could improve fuel economy and give extra power. However, run too lean and you risk engine failure because the engine runs too hot. Whereas running rich can waste fuel and increase pollution but will not damage the engine.
What is a good AFR?
Best performance for most vehicles is in the
12.5 to 13 AFR range
. Going too rich will have the opposite affect and decrease your performance. Getting up to cruising speed or getting ready to pass someone, you usually are looking for the performance to get up and go. … Best performance for most vehicles is around 12 AFR.
What is a rich air/fuel ratio?
An A/F ratio that contains less air and more fuel than the stoichiometric ratio is called a RICH fuel mixture. A rich mixture would be
one with a ratio less than 14.7:1 for gasoline
. A LEAN A/F mixture typically burns HOTTER and uses less fuel per mile driven, which improves fuel economy.
What is a bad air-fuel ratio?
If the ratio is too rich or too lean, the engine will not burn optimally burn the air-fuel mixture which can cause performance issues or use up too much fuel. The ideal air-fuel ratio that burns all fuel without excess air is
14.7:1
. This is referred to as the “stoichiometric” mixture.
What should air-fuel ratio be at WOT?
The best place for wide-open throttle (WOT) air/fuel testing is at the dragstrip. Short of that, you can do Second-gear bursts of 2 to 3 seconds each and have a passenger watch the meter. For your initial work, you should shoot for WOT air/fuel ratios between
2.5:1 to 13.0:1
.
What is Lambda used for?
In mathematics and computer programming, the Lambda symbol is used to
introduce “anonymous functions
.” Lambda notation distinguishes between variables used as mathematical arguments and variables that stand for predefined values.
How do you read Lambda values?
These lean (higher) and rich (lower) values are calculated for the Lambda scale
by dividing the observed A/F ratio with that particular fuel’s stoich
. For example: a 12.8:1 observed reading with gasoline is divided by 14.7 to produce a 0.87 Lambda reading.
What is Lambda in tuning?
Lambda tuning is
a form of internal model control (IMC)
that endows a proportional-integral (PI) controller with the ability to generate smooth, non-oscillatory control efforts when responding to changes in the setpoint.
What causes a high lambda reading?
The lambda reading on a gas tester is, to repeat, an indication of the air to fuel ratio, too high a lambda reading
relates to too much oxygen
. Too low a reading relates to too much fuel. … If the voltage is higher than this, i.e. 0.8 – 1.2 volts then there will be a rich running or excess fuel fault.
What is lambda reading?
Lambda represents
the ratio of the amount of oxygen actually present in a combustion chamber compared
to the amount that should have been present in order to obtain “perfect” combustion. … Thus a lean air/fuel ratio of, say, 16:1 would translate to a lambda value of 1.088. (To calculate, divide 16 by 14.7.)
Can you drive with a faulty lambda sensor?
Yes
, you can drive with a bad oxygen sensor if you can still start your engine and feel little difficulty driving. But don’t leave it alone for over a couple of days, as it might cause safety problems and lead to the malfunction of other parts of your vehicle.
