f. Lambda adjustment

f. Lambda adjustment

The control of the mixture strength is ensured by the Lambda sensor which measures the residual oxygen content in the exhaust gases.

Since below 300° C, the ceramic material is not activated, the Lambda sensor is electrically heated by means of a resistance (fitted inside) which is always supplied by a positive controlled by the ignition and is protected by a 10 A fuse.

With temperatures in excess of 300° C, the ceramic material becomes a conductor of oxygen ions consequently if the quantity of oxygen present at the two sides of the sensor differs a variation in voltage is created between the two poles.

The Lambda sensor causes the voltage variation signal to reach the control unit via terminals 9 and 10. The Lambda sensor measurements concerning the composition of the exhaust gases allow the electronic control unit to make constant corrections in real time to the mixture strength (weakening/enrichment) to keep it constantly oscillating around the stoichiometric value.

In the following conditions:

• starting,
• heavy load,
• deceleration (cut-off),

the Lambda sensor is disabled.