628813 - Operation
LAMBDA SENSORS
These are planar type and located upstream and downstream of the catalytic converter.The upstream sensor determines mixture control, known as the first loop.The control unit controls and manages injection so that the air/fuel ratio is always sufficiently close to a stoichiometric level to maximise catalytic converter efficiency. The mixture is enriched to ensure maximum performance under conditions of full power and high use.The downstream sensor diagnoses the conversion efficiency of the converter/s.Then:- lambda = 1 ideal mixture.
- lambda %gt; 1 lean mixture.
- lambda %lt; 1 enriched mixture.



- Power supply: 12V
- Internal resistance: 0.5 %divide; 1 kOhm.
CATALYTIC CONVERTER
The three-way catalytic converter makes it possible to keep down the levels of the three pollutant gases in the exhaust gases at the same time:- unburnt hydrocarbons (HC);
- carbon monoxide (CO);
- nitrogen oxides (NOx).
- oxidation of CO and HC to carbon dioxide (CO2) and water (H2O);
- reduction of Nox to nitrogen (N2).
![]() | The nobile metals in the catalytic converter suffer chemical attack if lead is present, partly due to the high temperature inside the converter. For this reason, the use of leaded fuel should be be avoided, otherwise the converter will be rapidly and irreversibly put out of service. Never use leaded fuel, even for a short time in an emergency. |
